Proxy Statement - Form DEF 14A

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

Filed by the Registrant ⌧Filed by a Party other than the Registrant ☐

Check the appropriate box:

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BLUEPRINT MEDICINES CORPORATION

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if Other Than the Registrant)

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Payment of Filing Fee (Check all boxes that apply):

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Dear Stockholders,

We had a tremendous year in 2023, achieving our 2023 corporate milestones across discovery, development, and commercial. We received U.S. and European regulatory approval for AYVAKIT^®/AYVAKYT^® (avapritinib) in indolent systemic mastocytosis, or indolent SM, and subsequently launched in both geographies; we nominated our development candidate BLU-808, an oral, potent, selective wild-type KIT inhibitor, for mast cell diseases; we advanced multiple early-stage clinical programs to inform a pipeline prioritization for 2024; and we did this all with financial discipline. Our strong execution has demonstrated that we can realize the harmony between our mission of bringing new, innovative medicines to patients while also building a strong and thriving business to create substantial value for our stockholders.

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As we enter 2024, AYVAKIT continues to be the foundation of our expanding business, with our early launch momentum putting AYVAKIT firmly on the path to achieve its potential as a greater than $2 billion product. With AYVAKIT's continued success, our growing revenue is enabling us to invest in compelling opportunities within our pipeline to drive longer-term growth as we strive to deliver additional transformational medicines in the future.

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To achieve our goals this year, we are focusing on three key aspects of our business:

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Our first area of focus is to continue the successful launch of AYVAKIT as the first and only approved treatment for indolent SM in the United States and Europe. Indolent SM is a debilitating, lifelong disease that requires chronic treatment to control burdensome symptoms that can severely impact a person's ability to work, take care of their family, and live a full life. AYVAKIT provides durable and clinically meaningful improvement across a broad range of symptoms with a well-tolerated, once-daily pill available in a range of doses to meet the medical needs across a spectrum of indolent SM and advanced SM patients. Indolent SM represents a sizeable, rare disease population of approximately 70,000 prevalent patients in the United States and Europe alone, roughly 15 times larger than the advanced SM population (for which AYVAKIT is also approved).

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In 2023, catalyzed by the first few months of launch, we delivered results in both our ability to reach patients and drive revenue, generating AYVAKIT net product revenues of $204.2 million for fiscal year 2023, up 84% from fiscal year 2022. At peak, AYVAKIT represents a greater than $2 billion potential market opportunity, and AYVAKIT's early launch trajectory toward this goal is on par with other successful rare disease medicines.

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Our second area of focus is to advance our portfolio of innovative, investigational medicines by scaling our SM leadership position to target additional allergic-inflammatory diseases where mast cells play a central role and advancing development of innovative therapies targeting cyclin dependent kinases in solid tumors. Our prioritized investments in these focused areas allow us to address areas of high medical needs in large patient populations where we can also leverage our expertise and infrastructure.

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A core component of our growth strategy is to build on our leadership position in SM by expanding to other diseases where mast cells play a core role in disease biology. We are uniquely positioned to build a franchise in mast cell-mediated diseases because of our scientific leadership and proprietary insights into mast cell and KIT biology, and our clinical and commercial capability and infrastructure. AYVAKIT and elenestinib, our next-generation candidate in development for SM, allow us to comprehensively address mast cell diseases driven by mutated KIT. Building on our success in SM, we are expanding into additional mast cell diseases representing much larger opportunities, beginning with chronic urticaria, where inhibition of wild-type KIT with BLU-808 represents a compelling therapeutic approach to impact fundamental disease biology. We believe the BLU-808 program can move quickly, building on the established proof-of-concept for KIT inhibition in these diseases and our track record of clinical execution and commercial success.

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We are also making strides in developing treatments for breast cancer and other solid tumors, by advancing the development of our CDK franchise anchored by the CDK2 inhibitor BLU-222, which has the potential to serve as the backbone of front-line combination therapy in breast cancer. Given the large market potential for BLU-222, we are seeking to collaborate with a partner who has a shared view of the importance of this target and in the compelling profile of BLU-222 as a potential best- and first-in-class CDK2 inhibitor. The BLU-222 program is an important near-term value driver for us, with key emerging clinical data expected this year and into early 2025. Beyond BLU-222, we have multiple early research efforts ongoing with potential to expand our CDK franchise, including BLU-956, a next-generation CDK2 kinase inhibitor, as well as targeted protein degradation efforts aimed at CDK2 and other undisclosed targets. This franchise approach, leveraging both our kinase inhibitor and targeted

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protein degradation platforms, uniquely positions our company to drive comprehensive innovation in targeting cyclin dependent kinases and has the potential to generate significant long-term value.

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Our third area of focus is to maintain a strong and durable financial position with cash management continuing to be a priority focus area for us in 2024. We anticipate that the combination of our strong revenue ramp and disciplined approach to our operating expenses will result in a continued decrease in cash burn throughout 2024, providing us with a clear pathway to potential profitability. The real value is what we can achieve over the long-term. As we grow AYVAKIT revenue throughout this year, we will still be just scratching the surface of the SM opportunity. We are confident that our early launch trajectory positions us squarely on the path to building a greater than $2 billion potential market opportunity with AYVAKIT in SM, as we continue to reach the thousands of patients who could potentially benefit from treatment with AYVAKIT this year and beyond.

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We know that our people are driving the success of our business, and we are committed to providing tools and fostering culture to drive high performance. We were named a "2024 Top Workplace USA" by USA Today for the third year running, and also recognized by Fast Company as one of the 10 most innovative companies in medicines and therapeutics in 2024. These recognitions span both the incredible impact we are having on patients globally as well as the impact our unique culture has on our "Blue Crew" team members and their ability to do their best work. We were also named as one of the "Top 100 Women-Led Businesses in Massachusetts" in 2023 by The Women's Edge, reflecting our commitment to diversity and championing strong corporate values. More importantly, our team members tell us directly how they feel about working at our company: In early 2024, 97% of our global workforce participated in our annual Engagement and Enablement survey, with 94% of our employees reporting that they were proud to work at Blueprint Medicines and 94% understanding how their role contributes to our goals.

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Today, we are well positioned to drive compelling near-term growth and invest in future innovation while maintaining financial discipline and enhancing stockholder value. I am confident that we have the right people, portfolio, and capabilities in place to achieve our goals in 2024 and realize our mission of changing the outcomes and extending the lives of patients while building a strong and thriving business for the long-term.

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On behalf of our board of directors, team members, patients and healthcare partners, thank you for your continued support and investment in Blueprint Medicines.

Sincerely,

Kate Haviland
President, Chief Executive Officer, and Director
On Behalf of the Board of Directors

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Cambridge, Massachusetts
April 25, 2024

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Dear Stockholders

You are cordially invited to attend the 2024 annual meeting of stockholders of Blueprint Medicines Corporation to be held on Wednesday, June 12, 2024, at 3:00 p.m., Eastern Daylight Time, virtually via live webcast at http://www.virtualshareholdermeeting.com/BPMC2024, where you will be able to vote electronically and submit questions. You will need the 16-digit control number included with these proxy materials to attend the annual meeting. At the annual meeting, stockholders will consider and vote on the following matters:

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In addition to the foregoing items of business, stockholders will be asked to consider and vote on any other business that may properly come before the annual meeting or any adjournment or postponement thereof.

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The foregoing items of business are more fully described in the proxy statement accompanying this notice.

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Stockholders of record at the close of business on April 12, 2024 will be entitled to notice of and to vote at the annual meeting or any adjournment or postponement thereof. We encourage you to access the annual meeting before it begins. Online check-in to access the meeting will start shortly before the meeting on June 12, 2024. If you attend the annual meeting at http://www.virtualshareholdermeeting.com/BPMC2024, you may vote electronically during the meeting even if you have previously returned a proxy. Stockholders will also have the opportunity to submit questions during the annual meeting through http://www.virtualshareholdermeeting.com/BPMC2024. A technical support telephone number will be posted on the log-in page that you can call if you encounter any difficulties accessing the virtual meeting during the check-in or during the meeting.

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We have elected to provide access to our proxy materials over the Internet under the Securities and Exchange Commission's "notice and access" rules. We believe that providing our proxy materials over the Internet expedites stockholders' receipt of proxy materials, lowers costs and reduces the environmental impact of our annual meeting.

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We encourage all stockholders to attend the annual meeting online. However, whether or not you plan to attend the annual meeting, we encourage you to read this proxy statement and submit your proxy or voting instructions as soon as possible. Please review the instructions on each of your voting options described in the proxy statement.

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Thank youfor your ongoing support and continued interest in Blueprint Medicines Corporation.

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By Order of the Board of Directors,

Tracey L. McCain, Esq.
Chief Legal and Compliance Officer

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Cambridge, Massachusetts
April 25, 2024

Important Notice Regarding Internet Availability of Proxy Materials

We are furnishing proxy materials to our stockholders primarily via the Internet. On April 25, 2024, we mailed to our stockholders a Notice of Internet Availability, or Notice, containing instructions on how to access our proxy materials, including this proxy statement and our 2023 annual report to stockholders. The Notice also instructs you on how to submit your proxy or voting instructions through the Internet or to request a paper copy of our proxy materials, including a proxy card or voting instruction form that includes instructions on how to submit your proxy or voting instructions by mail or telephone. Other stockholders, in accordance with their prior requests, have received e-mail access to our proxy materials and instructions to submit their vote via the Internet, or have been mailed paper copies of our proxy materials and a proxy card or voting instruction form.

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A copy of this proxy statement and our 2023 annual report to stockholders are available at www.proxyvote.com.

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Internet distribution of our proxy materials is designed to expedite receipt by stockholders, lower the cost of the annual meeting, and conserve natural resources. However, if you would prefer to receive printed proxy materials, please follow the instructions included in the Notice. If you have previously elected to receive our proxy materials electronically, you will continue to receive these materials via e-mail unless you elect otherwise.

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2023 marked a new era of accelerating growth at Blueprint Medicines. We launched AYVAKIT/AYVAKYT in the U.S. and Europe in indolent SM, growing our product revenue by 84% and putting us on the path to achieve a potential blockbuster opportunity of greater than $2 billion; we advanced and prioritized investments across our development and discovery portfolio; and we did all of this efficiently-decreasing our year-over-year costs and operating expenses. Our execution gives us strong momentum to drive additional success in 2024.

Figure is provided as a graphical representation and is not intended as financial guidance.

WE ARE CAPTURING A BLOCKBUSTER OPPORTUNITY WITH AYVAKIT IN SYSTEMIC MASTOCYTOSIS

In 2023, we received U.S. Food and Drug Administration, or FDA, and European Medicines Agency approval to market AYVAKIT/AYVAKIT as the first and only approved therapy for adults with indolent SM. Indolent SM represents a rare disease market of approximately 70,000 prevalent patients with high medical need in the United States and Europe. Supported by early launch momentum, we see significant headroom for strong and steady long-term revenue growth by treating more patients, continuing to grow the market, and expanding to new geographies, with AYVAKIT serving as the foundational driver of topline revenue growth for the company into the next decade. For example, we have seen approximately 280% growth over the last five years in diagnosed patients observable in claims data, who are being managed by an accessible prescriber base.

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AYVAKIT's compelling efficacy and safety profile, coupled with the chronic nature of indolent SM, mean that both new patient starts and the cumulative effect of patients staying on therapy for longer durations are important drivers of revenue this year and beyond.

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(1) Blueprint Medicines data on file, based upon visibility of unique patients in US claims data. (2) Cohen et al 2014.

WE ARE INVESTING IN SUSTAINABLE INNOVATION, AND FOCUSING OUR INVESTMENT TO DRIVE LONG-TERM GROWTH

Our research and development strategy focuses on designing and developing life-changing medicines in two core, strategic areas of allergy/inflammation and hematology/oncology. We pursue discovery, development, and commercialization of therapies that potently and selectively target known drivers of disease, with focused investment in therapeutic areas to build portfolio scale in areas where we can leverage our core expertise and business infrastructure.

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We have a pipeline of research and development programs that range from early science to advanced clinical trials in mast cell-mediated diseases, including SM and chronic urticaria, breast cancer, and other solid tumors vulnerable to CDK2 inhibition.

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A primary area of focus for us this year is to advance our portfolio of approved and investigational programs targeting mast-cell mediated diseases. We are uniquely positioned to drive novel science in this space, because of our scientific leadership in targeting KIT and our unique insights into mast cell biology, an important area of science that has been historically underappreciated. With AYVAKIT and elenestinib we are comprehensively covering mast

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cell diseases driven by mutated KIT, and this year we are expanding into much larger opportunities driven by wild-type KIT with BLU-808. We are particularly excited about the potential for BLU-808 to address the fundamental biology in a number of large diseases with significant medical need, starting with chronic urticaria. We believe this program will move quickly, building on our track record of successfully translating our discovery expertise in targeting KIT into clinical impact and now commercial success.

Figure is provided as a graphical representation and is not intended as financial guidance.

As we focus our investment and resource allocation to exciting research and development programs, where we have the opportunity to address high medical needs in large patient populations, and where we have existing expertise and infrastructure, we are ensuring that we maintain a strong and durable financial position. We anticipate that the combination of our strong revenue ramp and disciplined operating expenses may result in a continued decrease in cash burn in 2024, providing us with a clear pathway to potential profitability.

WE ARE PURPOSEFULLY EVOLVING OUR CORPORATE GOVERNANCE AS WE CONTINUE TO GROW

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WE CONTINUE TO DRIVE OUR ENVIRONMENTAL, SOCIAL AND GOVERNANCE INITIATIVES FORWARD

We are committed to an ESG strategy that prioritizes efforts in areas most closely aligned with our business. In 2023, we conducted a materiality assessment to evaluate perspectives from internal and external stakeholders around key ESG topics. Aligned with the results of this assessment, we focus our disclosures around three key pillars.

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Commitment to patients: Delivering medicines to patients is our core business purpose, and we do this in a way that builds trust with the patient and healthcare provider communities. Our access programs enable patients to fill their prescriptions rapidly, with many paying as little as zero dollars out of pocket, and for patients unable to pay, we provide free drug, which totaled approximately $60 million in the United States in 2023. We strive to protect patient privacy by safeguarding clinical and commercial data across the organization.

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Attracting, engaging and retaining our employees: We know our employees are central to the strength of our business, and we work hard to ensure they have the support they need to excel. We are intentional in how we build and nurture our culture, and cultivate a workplace that values well-being, continuous learning, and talent development. We aspire to become a biotech leader in practicing equity, sustaining diversity, strengthening inclusion, and emphasizing ongoing learning and meaningful initiatives to elevate employees from marginalized communities and enhance employees' sense of belonging.

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Responsible business practices: We protect the company by planning ahead where possible and preparing for the unknown. In 2023, we updated cybersecurity initiatives and training to guard against cyber-attacks and safeguard our employee, patient and customer data. We also recognize that climate change presents risk to the organization and are in the process of evaluating methods and means to quantify and report our greenhouse gas emissions in accordance with the recently adopted Securities and Exchange Commission, or SEC, regulations and the other state and federal regulations, as applicable.

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This proxy statement and the enclosed proxy card are being furnished in connection with the solicitation of proxies by the board of directors of Blueprint Medicines Corporation for use at the annual meeting of stockholders to be held online on Wednesday, June 12, 2024, at 3:00 p.m., Eastern Daylight Time, and at any adjournment or postponement thereof. The annual meeting will be held entirely online this year at http://www.virtualshareholdermeeting.com/BPMC2024. We encourage all stockholders to attend the annual meeting online. However, whether or not you plan to attend the annual meeting, we encourage you to read this proxy statement and submit your proxy or voting instructions as soon as possible. Additional details regarding attending the virtual annual meeting and voting at the meeting are provided below in section entitled "Frequently Asked Questions Regarding the Annual Meeting and Voting."

Unless otherwise stated, all references to "us," "our," "Blueprint," "Blueprint Medicines," "we," the "company" and similar designations refer to Blueprint Medicines Corporation and its consolidated subsidiaries. References to our website are inactive textual references only, and the contents of our website are not incorporated by reference into this proxy statement.

This proxy statement summarizes information about the proposals to be considered at the meeting and other information you may find useful in determining how to vote. The proxy card is the means by which you actually authorize another person to vote your shares in accordance with your instructions. We are making this proxy statement, the related proxy card and our 2023 annual report to stockholders available to stockholders for the first time on or about April 25, 2024.

A copy of our Annual Report on Form 10-K for the fiscal year ended December 31, 2023, as filed with the SEC, except for exhibits, will be furnished without charge to any stockholder upon written or oral request to Blueprint Medicines Corporation, 45 Sidney Street, Cambridge, Massachusetts 02139 or by calling 1-800-579-1639, by emailing [email protected] or by submitting a request over the Internet at www.proxyvote.com. This proxy statement and our Annual Report on Form 10-K for the fiscal year ended December 31, 2023 are also available on the SEC's website at www.sec.gov and the "Investors & Media-SEC Filings" section of our website, which is located at http://ir.blueprintmedicines.com.

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Our board of directors is divided into three classes, with one class of our directors standing for election each year. Directors in each class are elected at the annual meeting of stockholders held in the year in which the term for their class expires and hold office for a three-year term and until their resignation or removal or their successors are duly elected and qualified. In accordance with our certificate of incorporation and bylaws, our directors may fill existing vacancies on the board of directors.

The term of office of our Class III directors, Daniella Beckman, Habib Dable, and Lynn Seely, will expire at the 2024 annual meeting of stockholders. The nominees for Class III directors for election at the 2024 annual meeting of stockholders are Ms. Beckman, Mr. Dable and Dr. Seely. If any of Ms. Beckman, Mr. Dable and Dr. Seely are elected at the 2024 annual meeting of stockholders, such individual will be elected to serve for a three-year term that will expire at our 2027 annual meeting of stockholders and until such individual's successor is elected and qualified.

If no contrary indication is made, proxies in the accompanying form will be voted for Ms. Beckman, Mr. Dable and Dr. Seely or, in the event that any of Ms. Beckman, Mr. Dable and Dr. Seely is not a candidate or is unable to serve as a director at the time of the election (which is not currently expected), for any nominee who is designated by our board of directors to fill the vacancy.

VOTE REQUIRED AND Recommendation of the Board of Directors

The three nominees receiving the highest number of affirmative votes of the shares present in person or represented by proxy at the 2024 annual meeting of stockholders and entitled to vote on the election of directors will be elected to the board of directors. If a nominee receives a greater number of votes "withheld" than votes "for" such election, the nominee is required to promptly tender their resignation to the board of directors in accordance with our director resignation policy, as described in our corporate governance guidelines. The nominating and corporate governance committee will consider all factors it deems relevant in determining whether to recommend to the board of directors to accept any resignation offer. The board of directors will act on the nominating and corporate governance committee's recommendation within 90 days following certification of the election results. In deciding whether to accept the resignation offer, the board of directors will evaluate the factors considered by the nominating and governance committee and any additional information and factors that the board of directors believes to be relevant. The company will promptly publicly disclose the board of directors' decision in a periodic or current report filed with the SEC.

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Votes withheld from any director are counted for purposes of determining the presence or absence of a quorum, but have no other legal effect under Delaware law. Broker non-votes will have no effect on the outcome of this proposal.

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Information Regarding Directors

Set forth below are the names and certain information for each member of our board of directors, including the nominees for election as Class III directors, as of March 31, 2024. The information presented includes each director's and nominee's principal occupation and business experience for the past five years, and the names of other public companies of which the individual has served as a director during the past five years. The information presented below regarding the specific experience, qualifications, attributes and skills of each director and nominee led our board of directors to conclude that the individual should serve as a director. In addition, we believe that all of our directors and nominees possess the attributes or characteristics that the nominating and corporate governance committee expects of each director, which are described under the section titled "-Director Nomination Process."

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There are no family relationships among any of our directors or executive officers.

(1) Member of the audit committee. (2) Member of the compensation committee. (3) Member of the nominating and corporate governance committee.

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CLASS III DIRECTORS
TERM EXPIRING AT THE 2024 ANNUAL MEETING OF STOCKHOLDERS

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CLASS I DIRECTORS
TERM EXPIRING AT THE 2025 ANNUAL MEETING OF STOCKHOLDERS

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CLASS II DIRECTOR NOMINEES

TERM EXPIRING AT THE 2026 ANNUAL MEETING OF STOCKHOLDERS

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Corporate Governance

Our board of directors believes that good corporate governance is important to ensure that our company is managed for the long-term benefit of stockholders. This section describes key corporate governance guidelines and practices that our board of directors has adopted.

CORPORATE GOVERNANCE HIGHLIGHTS

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CORPORATE GOVERNANCE STRENGTHS

We are committed to exercising good corporate governance practices. We believe that good governance promotes the long-term interests of our stockholders and strengthens the accountability of our board of directors and management. Our corporate governance practices are primarily designed to:

* This figure is based on the Nasdaq Listing Rules for director independence.

CORPORATE GOVERNANCE MATERIALS

Complete copies of our corporate governance guidelines, committee charters and code of conduct are available on the "Investors & Media - Corporate Governance" section of our website, which is located at http://ir.blueprintmedicines.com. Alternatively, you can request a copy of any of these documents by contacting us at Blueprint Medicines Corporation, 45 Sidney Street, Cambridge, Massachusetts 02139, Attn: Investor Relations, telephone: (617) 374-7580, e-mail: [email protected].

CODE OF BUSINESS CONDUCT AND ETHICS AND CORPORATE GOVERNANCE GUIDELINES

Our board of directors has adopted a written code of business conduct and ethics that applies to our directors, officers and employees, including our principal executive officer, principal financial officer, principal accounting officer or controller, and persons performing similar functions. A copy of our code of business conduct and ethics is available on the "Investors & Media - Corporate Governance" section of our website, which is located at http://ir.blueprintmedicines.com. We intend to disclose on our website any amendments to, or waivers from, our code of business conduct and ethics that are required to be disclosed pursuant to the disclosure requirements of Item 5.05 of Form 8-K.

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Our board of directors has also adopted corporate governance guidelines to assist in the exercise of its duties and responsibilities and to serve the best interests of our company and our stockholders, which we periodically review and update, with the most recent update occurring in 2024. A copy of our corporate governance guidelines is available on the "Investors & Media - Corporate Governance" section of our website, which is located at http://ir.blueprintmedicines.com.

DIRECTOR RESIGNATION POLICY

In 2024, we implemented a director resignation policy, which is set forth in our corporate governance guidelines, a copy of which is available on the "Investors & Media - Corporate Governance" section of our website. The policy establishes that any director nominee who receives a greater number of "withhold" votes than "for" votes in an uncontested election of directors is required to tender their resignation promptly following the certification of the election results. Abstentions and broker non-votes, if any, are not counted as either a "withhold" or "for" vote.

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The nominating and corporate governance committee will promptly consider whether to accept or reject the resignation offer, or whether other action should be taken, and make a recommendation to the board of directors. The board of directors will act on the recommendation of the nominating and corporate governance committee no later than 90 days following the certification of the election results. In deciding whether to accept the resignation offer, the board of directors will evaluate the factors considered by the nominating and corporate governance committee and any additional information and factors that the board of directors believes to be relevant. Any director who tenders a resignation offer pursuant to the director resignation policy will not participate in the proceedings of either the nominating and corporate governance committee or the board of directors with respect to their own resignation offer. However, the director will remain active and engaged in all other activities of the board of directors, deliberations and decisions of the board of directors and its committees during the evaluation process conducted by the nominating and corporate governance committee and board of directors.

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We will promptly publicly disclose the board of directors' decision and, if applicable, the reasons for rejecting the tendered resignation in a periodic or current report filed with the SEC.

RISK OVERSIGHT

Our board of directors oversees the management of risks inherent in the operation of our business and the implementation of our business strategies. Our board of directors performs this oversight role by using several different levels of review. In connection with reviews of the operations and corporate functions of our company, our board of directors addresses the primary risks associated with those operations and corporate functions. In addition, our board of directors reviews the risks associated with our company's business strategies periodically throughout the year as part of its consideration of undertaking any such business strategies.

Each committee of our board of directors also oversees the management of our company risk that falls under the committee's particular purview and within its areas of responsibility. In performing this function, each committee has full access to management, as well as the ability to engage advisors. Our audit committee oversees our policies and programs related to our financial and accounting systems, accounting policies and investment strategies, internal audit function, investment strategies and cybersecurity. The audit committee also is responsible for addressing risks arising from related party transactions, if any. In connection with its risk management role, our audit committee meets privately with representatives from our independent registered public accounting firm and certain members of our executive team, as and when needed. The audit committee oversees the operation of our risk management program, including the identification of the primary risks associated with our business and periodic updates to such risks, and reports to our board of directors regarding these activities. Our compensation committee oversees risks associated with our compensation policies and practices to help ensure that such policies and practices do not incentivize or encourage excessive risk-taking. In early 2023, our board of directors engaged the compensation committee to assist in its oversight of human capital management, including recruiting, retention, career development, and equity, diversity and inclusion, or ED&I. Our nominating and corporate governance committee oversees risks related to our governance structure and succession planning, and our environmental, social and governance risk and reporting.

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BOARD DETERMINATION OF INDEPENDENCE

Our board of directors annually undertakes a review of the composition of our board of directors and its committees and the independence of each director. Based upon information requested from and provided by each director concerning their background, employment and affiliations, including family relationships, our board of directors has determined that each of our directors, with the exception of Jeffrey W. Albers and Kathryn Haviland, is an "independent director" as defined under Rule 5605(a)(2) of the Nasdaq Listing Rules. Mr. Albers is not an independent director under Rule 5605(a)(2) because he was employed as our president and chief executive officer through April 3, 2022 and as our executive chairman through December 31, 2022, and was engaged as a consultant to the company until December 31, 2023. Ms. Haviland is not an independent director under Rule 505(a)(2) because she is currently employed as our president and chief executive officer and was previously employed as our chief operating officer from January 2019 through April 2022, and as our chief business officer from January 2016 to January 2019. Our board of directors also determined that each of: Daniella Beckman, Lonnel Coats and Mark Goldberg, who comprise our audit committee; Lynn Seely, Habib Dable and Mark Goldberg, who comprise our compensation committee; and Lonnel Coats, Habib Dable and Lynn Seely, who comprise our nominating and corporate governance committee, satisfies the independence standards for such committees established by the SEC and the Nasdaq Listing Rules, as applicable, including in the case of all members of the audit committee, the independence requirements contemplated by Rule 10A-3 under the Securities Exchange Act of 1934, or the Exchange Act, and in the case of all members of the compensation committee, the independence requirements contemplated by Rule 10C-1 under the Exchange Act. In making such determinations, our board of directors considered the relationships that each such non-employee director has with our company and all other facts and circumstances our board of directors deemed relevant in determining independence, including the beneficial ownership of our capital stock by each non-employee director.

DIRECTOR NOMINATION PROCESS

The process followed by our nominating and corporate governance committee of our board of directors to identify and evaluate director candidates includes requests to board members and others for recommendations, meetings from time to time to evaluate biographical information and background material relating to potential candidates and interviews of selected candidates by members of the nominating and corporate governance committee and our board of directors.

CRITERIA, QUALIFICATIONS, EXPERIENCE AND DIVERSITY

In considering whether to recommend to our board of directors any candidate for inclusion in our board of directors' slate of recommended director nominees, including candidates recommended by stockholders, the nominating and corporate governance committee applies the criteria set forth in our corporate governance guidelines. These criteria include the candidate's experience at a strategic or policymaking level in a business, government, non-profit or academic organization of high standing, accomplishments in the candidate's respective field, the candidate's reputation for high ethical and moral standards, the candidate's time and ability to devote to the affairs of the company, and to the extent applicable, the candidates history of actively contributing to any boards of directors on which the candidate previously served.

The director biographies on pages 4-13 of this proxy statement provide details regarding each nominee's experience, qualifications, attributes and skills that led our nominating and corporate governance committee and our board of directors to conclude such individual should continue to serve as a director. Our nominating and corporate governance committee and our board of directors believe that each of the nominees has the individual attributes and characteristics required of each of our directors, and the nominees collectively possess the skill sets and specific experience desired of our board of directors as a whole.

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The following table and pie charts provide information regarding our board of directors:

* Ms. Beckman and Mr. Coats are our designated audit committee financial experts, pursuant to SEC rules and regulations.

** The Blueprint board leadership designation includes Chairperson of the Board, Lead Independent Director and/or Chair of a board committee.

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BOARD DIVERSITY

Our nominating and corporate governance committee and our board of directors are committed to equity, diversity and inclusion. We believe that our board of directors, taken as a whole, should embody a diverse set of skills, experiences and backgrounds. While our nominating and corporate governance committee does not assign any particular weighting of diversity or any other characteristic, the committee and our board of directors consider diversity, including with respect to gender, race and national origin, in evaluating nominees and directors. Our nominating and corporate governance committee's and our board of directors' priority in selecting board members is identification of individuals who will further the interests of our stockholders.

The table below provides certain highlights relating to the composition and diversity of our board of directors. Each of the categories listed in the below table has the meaning ascribed to it in Nasdaq Listing Rule 5605(f).

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STOCKHOLDER NOMINATIONS

Stockholders may recommend individuals to our nominating and corporate governance committee for consideration as potential director candidates by submitting their names, together with appropriate biographical information and background materials and a statement as to the amount of our beneficially owned common stock held by the stockholder or group of stockholders making the recommendation as of the date such recommendation is made, to Blueprint Medicines Corporation, Attention: Nominating and Corporate Governance Committee, 45 Sidney Street, Cambridge, Massachusetts 02139. Assuming that appropriate biographical and background material has been provided on a timely basis, the nominating and corporate governance committee will evaluate stockholder-recommended candidates by following substantially the same process, and applying substantially the same criteria, as it follows for candidates submitted by others. If the board of directors determines to nominate a stockholder-recommended candidate and recommends their election, then their name will be included in our proxy card for the next annual meeting.

Our amended and restated bylaws, or bylaws, also provide for proxy access that allows qualifying stockholders to directly nominate director candidates for consideration at an annual meeting of stockholders and have such candidate be included in our proxy materials for the applicable annual meeting. The key elements of our proxy access bylaw provisions are as follows:

The above table is only a summary of our proxy access provisions in our bylaws and is qualified in its entirety by our bylaws. A stockholder who wishes to nominate a proxy access nominee to be considered for election as a director at the 2024 annual meeting of stockholders must follow the procedures set forth in our bylaws as well as under "Stockholder Proposals."

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BOARD LEADERSHIP STRUCTURE

Under our corporate governance guidelines, the positions of chairperson of our board of directors and of chief executive officer may, but need not be, the same person. Additionally, our corporate governance guidelines provide that if the chairperson of the board of directors is not an independent director, then the independent directors may elect one independent director to serve as the lead independent director.

Jeffrey W. Albers has served as a director since 2014 and as the chairperson of our board of directors since June 2021. Mr. Albers possesses detailed and first-hand knowledge of the issues, opportunities, and challenges facing our business, making him well-suited to preside over meetings of, and oversee, our board of directors. Because Mr. Albers was employed by us in his role as president and chief executive officer through April 3, 2022, continued to be employed by us in his role as executive chairman through December 31, 2022, and was engaged as a consultant to the company until December 31, 2023, our board of directors does not currently consider him to be "independent" in his role as chairperson of the board of directors. Accordingly, in June 2021, our board of directors designated Lynn Seely as our lead independent director. Dr. Seely's service as lead independent director provides an effective independent voice in our leadership structure, encouraging objective oversight of management's performance and enhancing the effectiveness of the board of directors as a whole. As lead independent director, Dr. Seely presides over meetings of our independent directors, serves as a liaison between our chairperson and the independent directors and performs such additional duties as our board of directors may otherwise determine and delegate.

Our board of directors has three standing committees that currently consist of, and are chaired by, independent directors. Our board of directors delegates substantial responsibilities to the committees, which then report their activities and actions back to the full board of directors. We believe that the independent committees of our board of directors and their chairpersons promote effective independent governance. Meanwhile, the extensive company-specific experience and expertise of Mr. Albers and Ms. Haviland, together with the outside experience, oversight and expertise of our independent directors, allows for differing perspectives and roles regarding strategy development that benefit our stockholders.

We believe that our current leadership structure provides effective independent director oversight of management, while allowing our board to benefit from Mr. Albers' and Ms. Haviland's experience and leadership in our business, enabling Mr. Albers and Ms. Haviland to act as key links between our board of directors and other members of management and enhancing our ability to communicate our strategy clearly and consistently to our investors, employees and partners. We and our board of directors continue to review the leadership structure of the board on a regular basis.

BOARD OF DIRECTOR MEETINGS AND ATTENDANCE

Our board of directors held seven meetings and acted by unanimous written consent twice during the year ended December 31, 2023. During the year ended December 31, 2023, 80% of our directors then in office attended 100% of the aggregate number of meetings of our board of directors; all other directors then in office attended over 85% of the aggregate number of meetings of our board of directors; and each of our directors attended 100% of the number of meetings held by all committees of the board of directors on which such director then served.

Although we do not have a formal policy regarding attendance by members of our board of directors at our annual meeting of stockholders, we encourage all of our directors to attend. All members of our board of directors who were then directors attended our 2023 annual meeting of stockholders.

COMMITTEES OF THE BOARD OF DIRECTORS

We have established an audit committee, a compensation committee, and a nominating and corporate governance committee. Each of these committees operates under a charter that has been approved by our board of directors. A copy of each committee's charter can be found under the "Investors & Media - Corporate Governance" section of our website, which is located at http://ir.blueprintmedicines.com.

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AUDIT COMMITTEE

Our audit committee's responsibilities include:

The current members of our audit committee are Daniella Beckman, Lonnel Coats and Mark Goldberg. Ms. Beckman serves as chair of the audit committee. Our board of directors has determined that each of Ms. Beckman and Mr. Coats qualifies as an audit committee financial expert within the meaning of applicable SEC rules. The audit committee held six meetings during the year ended December 31, 2023, and each meeting was attended by all of the members of our audit committee.

COMPENSATION COMMITTEE

Our compensation committee's responsibilities include:

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The current members of our compensation committee are Lynn Seely, Habib Dable and Mark Goldberg. Dr. Seely serves as chair of the compensation committee. The compensation committee held nine meetings and acted by unanimous written consent 17 times (including 12 written consents approving monthly inducement grants to new hires as required by the inducement grant exception) during the year ended December 31, 2023. Each meeting was attended by all the compensation committee members.

The compensation committee may delegate its authority to our chief executive officer to grant certain equity awards to certain individuals, and our compensation committee has delegated such authority to Ms. Haviland with respect to certain equity awards. For more information, please see "Compensation Discussion and Analysis-Overview of Executive Compensation Process."

NOMINATING AND CORPORATE GOVERNANCE COMMITTEE

Our nominating and corporate governance committee's responsibilities include:

The current members of our nominating and corporate governance committee are Lonnel Coats, Habib Dable and Lynn Seely. Mr. Coats serves as chair of the nominating and corporate governance committee. The nominating and corporate governance committee held five meetings and acted by unanimous written consent twice during the year

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ended December 31, 2023. Each meeting was attended by all the members of the nominating and corporate governance committee.

COMMUNICATING WITH THE BOARD OF DIRECTORS

Our board of directors will give appropriate attention to written communications that are submitted by stockholders or other interested parties and will respond if and as appropriate. The chairperson of the board of directors is primarily responsible for monitoring communications from stockholders and other interested parties and for providing copies or summaries to the other directors as the chairperson considers appropriate.

Stockholders who wish to send communications on any topic to our board of directors (or any individual director) should address such communications to Blueprint Medicines Corporation, Attention: Board of Directors, 45 Sidney Street, Cambridge, Massachusetts 02139. Upon receipt of such communications, the correspondence will be directed to the appropriate person, including individual directors. A copy of any such written communication may also be forwarded to the company's legal counsel and a copy of such communication may be retained for a reasonable period of time. You may submit your concern anonymously or confidentially.

The audit committee oversees the procedures for the receipt, retention, and treatment of complaints received by the company regarding accounting, internal accounting controls or auditing matters, and the confidential, anonymous submission in the United States, and elsewhere as permitted by law, by employees of concerns regarding questionable accounting or auditing matters. The company has also established a toll-free telephone number, the "BlueCares" hotline, for the reporting of such activity, which is (844) 857-5642 or you can visit Blueprintmedicines.ethicspoint.com to submit any questions or concerns.

BOARD RESPONSE TO STOCKHOLDER FEEDBACK

At our 2023 annual meeting of stockholders, Alexis Borisy received less than 50% of the votes cast. Based on stockholder outreach following the 2023 annual meeting, the feedback we received regarding Mr. Borisy was not related to his experience or other qualifications; rather, it was specifically related to over-boarding concerns. In April 2023, shortly before our over-boarding policy became effective, Mr. Borisy committed to reducing his service on other public company boards to be in compliance with our over-boarding policy by the record date for our 2024 annual meeting of stockholders. In 2023, Mr. Borisy's service on the board of directors of EQRx, Inc. ended when EQRx was acquired by Revolution Medicines. In addition, Mr. Borisy did not stand for reelection to the board of directors of OPKO Health, Inc. at their 2024 annual meeting of stockholders. As a result, Mr. Borisy met his commitment to be in compliance with our over-boarding policy in a timely manner. BecauseMr. Borisy has addressed these specific stockholder concerns and has continuously and consistently devoted the time and attention necessary to fulfill his responsibilities as a director, he continues to serve as a valued and active member of our board of directors. In 2023, Mr. Borisy attended 100% of the meetings of our board of directors. In addition, Mr. Borisy consistently makes himself available to our executive team and other company leaders outside of meetings. Further, Mr. Borisy brings unique and valuable experience and insights through his more than 25 years of experience with founding, financing and leading more than fifteen life sciences companies - including ten Nasdaq-listed companies - and serves a critical role in the continuing evolution of our company and strategic vision.

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The following provides more detail on the various topics discussed and our responsive actions:

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Director Compensation

Our board of directors has adopted a non-employee director compensation policy, which is designed to provide a total compensation package that enables us to attract and retain, on a long-term basis, high caliber non-employee directors. Under our non-employee director compensation policy, our non-employee directors were compensated as follows in 2023, which amounts remain unchanged from the prior year policy amounts:

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The stock options granted to our non-employee directors will have an exercise price equal to the closing price of our common stock as reported on the Nasdaq Global Select Market on the date of grant and will expire ten years after the date of grant. The initial stock options granted to new non-employee directors will vest in equal monthly installments over a three-year period following the grant date. The initial restricted stock units, or RSUs, granted to new non-employee directors will vest in equal annual installments over a three-year period beginning on the one-year anniversary of the grant date. The annual stock options and the annual RSUs granted to our non-employee directors will vest in full upon the earlier of the first anniversary of the date of grant or the date of the following annual meeting of stockholders. Any initial and annual equity awards granted to each of our non-employee directors will automatically accelerate and become fully vested and exercisable upon the non-employee director's termination due to death or disability or upon a sale event (as defined in the 2015 Plan or, if approved during our 2024 annual meeting of stockholders, the 2024 Plan). In addition, each non-employee director has the right to elect to receive all or a portion of their annual cash compensation under the non-employee director compensation policy in the form of stock options to purchase our common stock. Any such election must be made before the start of our fiscal year and any such stock options will vest quarterly over a one-year period. Except as mentioned above, vesting of all stock options and RSUs is subject to the non-employee director's continued service on the board of directors or subject to continued service as a consultant, director or employee of the company or any of its affiliates, as applicable.

All cash fees will be paid quarterly, in arrears, or upon the earlier resignation or removal of the non-employee director. The amount of each payment will be prorated for any portion of a quarter that a non-employee director is not serving on our board of directors, based on the number of calendar days served by such non-employee director.

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Each non-employee director is also entitled to reimbursement for reasonable travel and other expenses incurred in connection with attending meetings of the board of directors and any committee on which the director serves.

In December 2020, our board of directors adopted stock ownership guidelines designed to ensure that our directors and senior executive officers are focused on both short- and long-term objectives and to better align their interests with other stockholders. In April 2023, we amended and restated our stock ownership guidelines, eliminating shares underlying vested and unexercised "in-the-money" stock option awards from the calculation of requisite stock ownership levels for the covered parties. All of our directors remained in compliance following the amendment. See "Other Compensation Policies and Practices - Stock Ownership Guidelines" for more information.

The following table sets forth a summary of the compensation for our non-employee directors during 2023.

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Pursuant to the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010, or the Dodd Frank Act, and Section 14A of the Exchange Act, at least once every six calendar years, our stockholders are entitled to vote on whether a non-binding advisory vote on the compensation of our named executive officers, commonly known as a "say-on-frequency" vote, should occur every year, every two years or every three years. At the 2018 annual meeting of stockholders, our board of directors, valuing good corporate governance and a regular dialogue on executive compensation, recommended that the stockholders approve a non-binding advisory vote on the frequency of future say-on-pay votes on an annual basis.

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Approximately 94% of the stockholder votes cast at the 2018 annual meeting of stockholders were for the company's recommendation, and in response the company has since held an annual say-on-pay vote. At the 2024 annual meeting of stockholders, stockholders will once again be invited to specify one of the following options for this say-on-frequency proposal, as indicated on the proxy card: one year, two years, three years or abstain from voting. Stockholders are not voting to approve or disapprove the recommendation of the board of directors.

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VOTE REQUIRED AND RECOMMENDATION OF THE BOARD OF DIRECTORS

The frequency option that receives the majority of the votes cast on the matter will be considered the frequency preferred by the stockholders. The advisory vote on the frequency of future advisory votes on named executive officer compensation is non-binding on the company and / or the board of directors. Although non-binding, our board of directors will consider the voting results when making future decisions regarding frequency of advisory votes on executive compensation. Abstentions and broker non-votes will have no effect on the outcome of this proposal.

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We are providing our stockholders the opportunity to vote to approve, on an advisory non-binding basis, the compensation of our named executive officers as disclosed in this proxy statement in accordance with the SEC's rules. This proposal, which is commonly referred to as "say-on-pay," is required by the Dodd-Frank Act, which added Section 14A to the Exchange Act. Our executive compensation program is designed to reward value creation for stockholders and to attract, motivate, and retain a highly skilled team of executive officers, who are critical to our success. Under this program, our named executive officers are rewarded for the achievement of our short- and long-term strategic and financial goals, which we believe serves to enhance short- and long-term value creation for our stockholders.

The section of this proxy statement titled "Executive Compensation" beginning on page 34, including "Compensation Discussion and Analysis," describes in detail our executive compensation program and the decisions made by our compensation committee with regard to such program. As we describe in greater detail in the "Compensation Discussion and Analysis" section, we generally strive to provide our named executive officers with a mix of short-term and long-term performance-based incentives to encourage consistently strong performance, and our board of directors believes that this link between compensation and the achievement of our near- and long-term business goals has helped drive our performance over time. Atthe same time, we believe our program does not encourage excessive risk-taking by management.

Our board of directors is asking stockholders to approve the following resolution:

RESOLVED, that the stockholders of Blueprint Medicines Corporation approve, on a non-binding advisory basis, compensation paid to the company's named executive officers, as disclosed pursuant to Item 402 of Regulation S-K, including the "Compensation Discussion and Analysis," the compensation tables and narrative discussion included therein.

You are being asked to approve on a non-binding advisory basis, the compensation paid to our named executive officers as set forth in the Compensation Discussion and Analysis, Summary Compensation Table and related notes and narrative set forth in this proxy statement. This vote is not intended to address any specific compensation item, but rather the overall compensation paid to our named executive officers and the philosophy, policies and practices described herein.

Vote Required and RECOMMENDATION OF THE BOARD OF DIRECTORS

Approval of this resolution requires the affirmative vote of a majority of the votes cast on this proposal. As a non-binding advisory vote, the outcome of the vote on this proposal is non-binding and does not overrule any decision by the company or the board of directors (or any committee thereof), create or imply any change to the fiduciary duties of the company or the board of directors (or any committee thereof), or create or imply any additional fiduciary duties for the company or the board of directors (or any committee thereof). However, our compensation committee and board of directors value the opinions expressed by our stockholders in their vote on this proposal and intend to consider carefully the outcome of the vote when making future compensation decisions for named executive officers. Abstentions and broker non-votes will have no effect on the outcome of this proposal.

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Executive Officers

Certain information regarding our executive officers who are not also directors, as of March 31, 2024, is set forth below.

Percy H. Carter, M.B.A., Ph.D. has served as our chief scientific officer since May 2021. Dr. Carter previously served as chief scientific officer at FibroGen, Inc. from September 2020 to May 2021. From June 2019 to September 2020, he served as global head of discovery sciences at Janssen Pharmaceuticals, Inc., a division of Johnson & Johnson, where he led more than 700 employees comprising several key research and discovery functions and drove the synthetic discovery strategy in collaboration with partners across various therapeutic areas. From August 2001 to May 2019, Dr. Carter held roles of increasing responsibility in drug discovery, covering all therapeutic areas, drug platforms and stages of discovery at Bristol-Myers Squibb Company, or BMS. This included serving as senior vice president and head of discovery between November 2018 and May 2019, and head of discovery chemistry & molecular technologies from October 2016 to November 2018. Prior to his experience at BMS, he was senior research scientist in chemical and physical sciences at DuPont Pharmaceuticals Company, until it was acquired by BMS in 2001. Dr. Carter is an inventor or co-inventor on 28 U.S. patents and has authored or co-authored more than 80 peer-reviewed publications. Dr. Carter has served as a member of the board of directors of HiFiBio Therapeutics since 2022 and currently serves as an independent director. Dr. Carter received an A.B. in Chemistry from Dartmouth College and a Ph.D. in Organic Chemistry from Harvard University. In addition, he received an M.B.A. from Massachusetts Institute of Technology.

Debra Durso-Bumpus has served as our chief people officer since February 2020. She has been with us since April 2015 as a member of the executive team and previously served as our senior vice president, human resources. Bringing nearly 20 years of experience focused on providing strategic direction to companies on people matters, managing rapid growth and creating and maintaining high performance cultures, Ms. Durso-Bumpus has operated in a number of leadership positions. Prior to joining Blueprint Medicines, she served as the interim head of human resources at Cubist Pharmaceuticals, Inc. or Cubist, where she was appointed to lead the post-merger human resources integration following the acquisition of Cubist by Merck & Co. Between April 2009 and the acquisition, Ms. Durso-Bumpus served as the global senior director for talent management and organizational development at Cubist, where she was primarily responsible for building talent and leadership strength and depth while managing change on a global scale to create a cohesive and highly differentiated culture. Prior to Cubist, she served as the North American manager of talent acquisition and workforce planning at Holcim, Inc., in Waltham, MA. Ms. Durso-Bumpus serves as a member of the board of directors for the Massachusetts Biotechnology Education Foundation, a nonprofit organization committed to supporting science and biotechnology education in Massachusetts through school programs, workforce training and lifelong learning. Ms. Durso-Bumpus received a B.S. in business management from Bentley University.

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Becker Hewes, M.D. has served as chief medical officer since January 2021. Dr. Hewes previously served as our senior vice president of clinical development from May 2020 to January 2021. Prior to joining us, he served as chief medical officer of Repertoire Immune Medicines, Inc. from February 2017 to May 2020, where he built their multidisciplinary clinical and biomarker team and advanced its immuno-oncology programs into clinical development. From June 2013 to February 2017, Dr. Hewes served as executive director of translational clinical oncology at the Novartis Institutes for BioMedical Research, or Novartis, where he led clinical development and translational medicine efforts for multiple early-stage oncology programs through clinical proof-of-concept, including Kisqali® (ribociclib), a targeted therapy approved to treat breast cancer, and other programs combining novel therapies. Prior to joining Novartis, he held roles of increasing responsibility related to clinical development in oncology and hematology within AstraZeneca PLC, Genzyme Corporation (which was later acquired by Sanofi S.A.) and Wyeth Pharmaceuticals Inc., including leading registration programs for Bosulif^® (bosutinib) and Torisel^® (temsirolimus) for chronic myelogenous leukemia and mantle cell lymphoma, respectively. Before joining industry, he conducted immuno-oncology research at the Emory Vaccine Center while treating patients as a pediatric oncologist at Children's Healthcare of Atlanta. Dr. Hewes holds an M.D. from the Georgetown University of Medicine and a B.S. from Vanderbilt University.

Ariel Hurley has served as our senior vice president, finance and principal accounting officer since January 2023. Ms. Hurley previously served as our vice president, finance, and controller and principal accounting officer from March 2019 to December 2022, as our senior director, controller from January 2016 to February 2019 and as our director, controller from September 2014 to December 2015. Prior to joining us, from December 2005 to September 2014, Ms. Hurley served in various accounting and finance roles at Millennium Pharmaceuticals, Inc. (now a wholly-owned subsidiary of Takeda Pharmaceutical Company Limited). Ms. Hurley began her career at Deloitte & Touche, LLP and earned her certified public accountant license in Massachusetts. Ms. Hurley received a B.S. in accounting from Providence College.

Michael Landsittel, M.B.A. has served as our chief financial officer since January 2019. Mr. Landsittel previously served as our vice president, finance from February 2016 to January 2019 and as our senior director, finance from September 2014 to February 2016. Prior to joining us, Mr. Landsittel served as senior director of finance at Algeta ASA, from October 2012 to July 2014, where he led the U.S. organization's finance and operations efforts, which ultimately supported the successful launch of the prostate cancer drug XOFIGO® (radium Ra 223 dichloride). Before joining Algeta ASA, from March 2012 to October 2012, he was the director of financial planning at Infinity Pharmaceuticals, Inc., or Infinity, where he was responsible for budgeting and forecasting, including support of Infinity's long-range planning and capital markets activities. Prior to Infinity, from August 2002 to March 2012, Mr. Landsittel held multiple business development and strategic planning roles of increasing responsibility at Genzyme Corporation (which was later acquired Sanofi S.A.). Mr. Landsittel began his career at Arthur Andersen LLP, and is a registered certified public accountant in Illinois. Mr. Landsittel received a B.B.A from the University of Michigan and an M.B.A. from the Tuck School of Business at Dartmouth College.

Philina Lee, Ph.D. has served as our chief commercial officer since April 2022. Dr. Lee previously served as our senior vice president, head of portfolio strategy and program management from January 2021 to April 2022, where she was responsible for providing strategic and operational leadership across the company's portfolio, our vice president, marketing and precision medicine from August 2019 to December 2020, our vice president, commercial strategy and operations from July 2017 to August 2019 and as our senior director, new product strategy and development from August 2014 to June 2017. During her tenure, Dr. Lee has been instrumental in building the company's portfolio from research-stage onwards, laying the groundwork for the commercial strategy that is driving the successful launches of AYVAKIT® (avapritinib) and GAVRETO® (pralsetinib). Previously, Dr. Lee held product strategy and marketing roles of increasing responsibility at Algeta ASA, Sanofi S.A. and Genzyme Corporation (which was later acquired by Sanofi S.A.). Dr. Lee has served on the board of Fusion Pharmaceuticals since February 2021 and currently serves as a member of their nominating and corporate governance and the research and development committees. Dr. Lee earned a B.S. in biochemistry from the University of Alberta, and a Ph.D. in cell biology from the Massachusetts Institute of Technology.

Tracey L. McCain, Esq. has served as our executive vice president and chief legal officer since September 2016 and as our chief compliance officer since June 2017. Prior to joining us, from January 2016 to September 2016, Ms. McCain served as senior vice president and head of legal of Sanofi Genzyme, a global business unit of Sanofi S.A., or Sanofi, Ms. McCain held roles of increasing responsibility after joining Genzyme Corporation in May 1997,

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including becoming its general counsel after Genzyme Corporation was acquired by Sanofi in 2011. In her capacity as senior vice president and general counsel of Genzyme Corporation from May 2011 to December 2015, she oversaw all aspects of its legal department in the United States and Europe, including general corporate, commercial and intellectual property matters, and support of business development initiatives. Prior to Genzyme's acquisition, Ms. McCain was also responsible for managing the securities and employment law teams and support of non-patent litigation. Before joining Genzyme, Ms. McCain was an associate at the law firm Palmer & Dodge LLP. Ms. McCain has served as a member of the board of directors of Kiniksa Pharmaceuticals, Ltd. since February 2018 and currently serves on its audit committee. She also served as a member of the board of directors of ImmunoGen, Inc. and sat on its audit committee from November 2021 to February 2024 when ImmunoGen, Inc. was acquired by AbbVie, Inc. She also serves on the board of trustees of the Dana Farber Cancer Institute. Ms. McCain holds a B.A. from the University of Pennsylvania with a major in political science and a J.D. from Columbia University School of Law.

Christopher K. Murray, Ph.D. has served as our executive vice president and chief technical operations and quality officer since January 2023. Dr. Murray previously served as our senior vice president, technical operations from October 2017 to December 2022 with responsibility for overseeing all aspects of Chemistry, Manufacturing and Controls, or CMC, for the company's global commercial products and other compounds, as well as CMC management from early preclinical development to commercial launch and distribution. Prior to joining us, from January 2014 to May 2017, Dr. Murray served as vice president, technical operations at ARIAD Pharmaceuticals, Inc., or ARIAD. In this role, Dr. Murray oversaw all aspects of commercial and clinical manufacturing, supply chain and logistics, process development, quality control and analytical chemistry for ARIAD's approved products and product candidates, including ICLUSIG® (ponatinib) and ALUNBRIG® (brigatinib). From 2004 to December 2013, Dr. Murray held multiple roles of increasing responsibility at ARIAD related to process development, manufacturing and clinical supply. Prior to joining ARIAD, Dr. Murray served in various positions with Allos Therapeutics, Inc. and Hauser Inc. related to clinical and commercial manufacturing and supply of active pharmaceutical ingredients. Dr. Murray is an inventor or co-inventor on more than 25 U.S. patents. Dr. Murray holds a B.S. from Hope College with a major in chemistry and a Ph.D. in organic chemistry from the University of Chicago.

Fouad Namouni, M.D. has served as our president, research and development, since September 2020. Prior to joining us, Dr. Namouni served in leadership roles at Bristol Myers Squibb Company since 1999, including as the global development lead for the its practice-changing cancer immunotherapy franchise. Most recently, he served as senior vice president and head of oncology development from August 2016 to April 2020 with the responsibility for driving product development plans from early-stage clinical development through commercialization across a portfolio of nearly 30 drug candidates. Previously, Dr. Namouni served as head of global medical affairs overseeing 1,700 employees worldwide from September 2015 to September 2017 and head of development for OPDIVO® (nivolumab) and YERVOY® (ipilimumab), immunotherapy medications used in the treatment of cancer, from January 2011 to September 2015. Dr. Namouni brings more than 20 years of oncology and cancer immunotherapy drug development expertise, as well as clinical experience as a pediatric oncologist. He holds an M.D. from the University of Annaba Medical School in Algeria and a Pediatrics degree from Université Rene Descartes in Paris, France. Additionally, Dr. Namouni received a Pediatric Oncology and Hematology degree and an M.S. in clinical and experimental pharmacology from Université Paris-Sud in France.

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Christina Rossi, M.B.A. has served as our chief operating officer since April 2022. She previously served as our chief commercial officer from October 2018 to April 2022 and has overseen the commercial launches of AYVAKIT® (avapritinib) and GAVRETO® (pralsetinib) across multiple indications and geographies, including the creation of commercial infrastructure and successful market access efforts in the U.S. and Europe. Prior to joining us, from January 2016 to October 2018, Ms. Rossi served as the Multiple Sclerosis business unit head, North America, at Sanofi Genzyme, a global business unit of Sanofi S.A. In this role, she was responsible for all aspects of the financial performance of Sanofi Genzyme's multiple sclerosis franchise and increased market share for existing products, led the launch of new therapies and optimized operations to accelerate patient access. Previously, Ms. Rossi served as vice president, Multiple Sclerosis Sales at Sanofi Genzyme from May 2014 to December 2015 and vice president, Multiple Sclerosis Patient and Provider Services at Sanofi Genzyme from June 2012 to May 2014. Prior to joining Sanofi Genzyme, Ms. Rossi served in various roles at Biogen, Inc., or Biogen, including head, commercial strategy for Eidetica Biopharma GmbH, Biogen's biosimilar-focused venture, and U.S. brand leader for TYSABRI® (natalizumab). In addition, Ms. Rossi consulted in the healthcare practice at the Boston Consulting Group. Ms. Rossi has served as a member of the board of directors of Xilio Therapeutics, Inc. since April 2021 and currently serves as a member of its audit committee and as chair of its compensation committee. Ms. Rossi holds a B.S. in biology, cum laude, from Duke University and an M.B.A. from Harvard Business School.

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Executive Compensation

COMPENSATION DISCUSSION AND ANALYSIS

Our compensation committee is responsible for reviewing and approving the compensation of our named executive officers, including base salary, cash and equity incentive compensation levels, severance arrangements, change-in-control benefits and other forms of executive compensation. This committee is also responsible for evaluating our company's performance against its goals and making related recommendations to our board of directors, assessing the performance of our named executive officers, and ensuring our compensation program is aligned with the objectives described below and competitive with those of other companies in our industry that vie for talent with us. This section discusses the principles underlying our compensation committee's policies and decisions with respect to the compensation of our named executive officers.

For 2023, our named executive officers were as follows:

EXECUTIVE SUMMARY

We are a fully integrated, commercial-stage, global biopharmaceutical company that invents life-changing medicines in two core, strategic areas of allergy/inflammation and oncology/hematology. We pursue discovery, development, and commercialization of therapies that potently and selectively target known drivers of disease, with focused investment in therapeutic areas where we can leverage our core expertise and business infrastructure to bring scale to our science. We are bringing AYVAKIT®/AYVAKYT® (avapritinib) to people living with SM in the United States and Europe. Additionally, we have a pipeline of research and development programs that range from early science to advanced clinical trials in mast cell-mediated diseases, including SM and chronic urticaria, breast cancer, and other solid tumors vulnerable to CDK2 inhibition.

Since 2011, we have advanced a drug discovery approach that combines evolving biological insights with our proprietary research platform and drug design capabilities, which currently includes kinase inhibition and targeted protein degradation. We aim to rapidly and reproducibly translate science into a durable clinical benefit for broad populations of patients with significant medical needs, including patients with mast cell-mediated diseases, breast cancer and other solid tumors. Our focused business model integrates our research engine with robust clinical development and commercial capabilities in allergy/inflammation and solid tumors to create a sustainable cycle of innovation.

In 2023, we made substantial progress toward our vision to bring life-changing medicines to as many patients with allergy and inflammation, cancer and hematologic disorders as possible. We achieved a number of significant milestones in 2023, including the following, toward our corporate goals described below in this Compensation Discussion and Analysis section.

Enable a long-term positive impact for patients globally through the efficient, sustainable, and compliant execution of our business

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Thoughtfully and urgently discover and develop transformative medicines that benefit broad patient populations with unmet need

Sustain and reinforce our differentiated culture to attract and retain diverse and highly capable talent; and promote our leadership in precision medicine to expand our external engagements

COMPENSATION ELEMENTS

Our compensation committee seeks to ensure that our compensation program is aligned with the interests of our stockholders and our business goals and that the total compensation paid to each of our named executive officers is fair, reasonable and competitive. As described in more detail below, key elements of our compensation program include the following:

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In addition to our direct compensation elements, the following features of our compensation program are designed to align with stockholder interests and market best practices while being able to achieve our stated objectives and philosophy and support our ambitious business goals:

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COMPENSATION OBJECTIVES AND PHILOSOPHY

Our compensation committee believes that the most effective compensation program is one that rewards value creation for stockholders and progress towards achieving our mission of delivering life-changing medicines to address unmet medical needs of our patients and that promotes company performance. The objectives of our compensation program are to:

To achieve its objectives, our compensation committee evaluates our executive compensation program with the goal of setting total compensation at levels that align with our total rewards strategy, size and company life stage. Specifically, below are the key elements targeted by our compensation committee for our 2023 executive compensation programs:

Base salary

As discussed below, in seeking to ensure that base salaries reflect each executive's experience, performance and responsibility, our compensation committee applies judgment in establishing targeted pay levels, taking into account not only competitive market data, but also factors such as organizational and individual performance, scope of responsibility, critical needs and skill sets, leadership and succession planning. The committee believes the current base salaries for our named executive officers are competitive with the base salaries of other companies in our industry and region that compete with us for executive talent.

Annual performance-based cash incentive compensation

Our compensation program links a substantial portion of our named executive officers' annual compensation to the achievement of pre-determined corporate and individual performance goals as part of the annual executive bonus plan adopted by our board of directors, or the executive bonus plan. Those goals include: scientific, business, organizational and operational goals such as our commercialization activities; progress in our clinical trials and research programs; key research and development achievements; maintaining the strong financial health of the company, including implementation of appropriate financing strategies; maintaining and establishing key strategic relationships; sustaining and reinforcing our differentiated culture through retention of high-performing talent, and progressing our ED&I goals and practices; and achievement of desired financial metrics. Our compensation committee uses competitive compensation data from annual total compensation of peer companies generally to help make decisions on annual performance-based cash incentive compensation, and imposed caps on executive bonus plan payouts at 150% of the target payout level.

Equity incentive compensation

We provide a significant portion of our executive compensation in the form of stock options and RSUs that vest over time contingent upon continued service, which we believe helps to retain our executives and aligns their interests with those of our stockholders by allowing them to participate in the longer-term success of our company as reflected in the appreciation of our stock price. Additionally, in 2023 we also introduced PSUs for the executive officers serving on our executive team, which require both continued service and performance of our relative total stockholder return in order to vest, balancing both retention and further strengthened alignment with company performance and stockholder interests. When determining equity incentive compensation for our named executive officers, our compensation committee considers a host of factors in comparison to our peer group, including the following: annual long-term incentive target values, annual equity awards expressed as a percent of total shares outstanding, total annual and cumulative dilution, the retentive value of outstanding awards and total equity ownership, and the equity compensation practices and vehicles of other companies in our industry that compete with us for talent. Given the dynamic biopharmaceutical market, our compensation committee does not overemphasize any one of these perspectives. Rather, they take a holistic view, further considering the factors enumerated above, the achievement of our corporate goals and the impact on total stockholder return, when determining actual award levels for each of the named executive officers.

We believe that targeting and delivering overall compensation in this manner, including the strong emphasis on pay-for-performance and at-risk pay, are necessary and appropriate in order to attract and retain the quality of

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talent we need to successfully grow our business, achieve our goals, sustain strong performance, and seek to ensure that compensation levels are competitive with other companies against which we compete for talent. In addition, we believe this approach to overall compensation creates a strong alignment with stockholder value and encourages long-term value creation. However, any individual employee's compensation may vary from the targeted pay framework, based on the unique responsibilities and requirements of the position, experience and other qualifications, internal parity relative to similar positions within the company, and individual or company performance relative to performance goals and our peer group to ensure appropriate pay-for-performance alignment. While we do not have a formal or informal policy for allocating between long-term and short-term compensation, between cash and non-cash compensation or among different forms of non-cash compensation, we generally strive to provide our named executive officers with a balance of short-term and long-term incentives to encourage consistently strong performance to help contribute sustained value over time.

For 2023, 88% of our chief executive officer's and 75% of our other named executive officers' target compensation was performance-based through their pre-determined annual performance goals (through our corporate performance goals for our chief executive officer and corporate and individual performance goals for our named executive officers) tied to our executive bonus plan and long-term equity awards to incentivize performance to drive stock appreciation and, therefore, at-risk pay:

* Based on 2023 annualized salary, bonus opportunity at target for 2023 performance, and grant date fair value of long-term equity incentive awards granted in 2023, all of which is averaged for our named executive officers other than our chief executive officer. Please note that the above excludes all other unspecified forms of compensation and therefore does not agree to the Summary Compensation Table.

ANNUAL SAY-ON-PAY VOTE ON EXECUTIVE COMPENSATION

The compensation committee considered the results of the non-binding stockholder advisory votes on the compensation of our named executive officers conducted at our 2023 annual meeting of stockholders, commonly referred to as a "say-on-pay" vote. As reported in our current report on Form 8-K, filed with the SEC on June 27, 2023, approximately 98% of the votes cast on the proposal expressed support for the compensation program offered to our named executive officers as disclosed in last year's proxy statement. The compensation committee appreciates this support and believes it indicates that our stockholders are supportive of our current executive compensation structure and policies. As such, the compensation committee made no changes to our 2023 executive compensation program as a result of the say-on-pay vote.

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Further, our board of directors has elected to conduct the non-binding advisory say-on-pay vote annually, thereby giving our stockholders the opportunity to provide feedback on the compensation of our named executive officers each year. We will be conducting our annual say-on-pay vote as described in Proposal 3 of this proxy statement at our 2024 annual meeting of stockholders. Our board of directors and our compensation committee will consider the outcome of the say-on-pay vote, as well as feedback received throughout the year, when making compensation decisions for our named executive officers in the future.

OVERVIEW OF EXECUTIVE COMPENSATION PROCESS

ROLE OF THE COMPENSATION COMMITTEE

The compensation committee works closely with Aon's Human Capital Solutions practice, a division of Aon plc, or Aon (formerly known as Radford), throughout the year to develop our executive compensation program and to align pay with performance, stockholder interests, and pay at our peer companies. Annualized base salaries and annual performance-based cash incentives and equity incentive awards for all employees are generally determined in the first quarter of the year based on company and individual performance in the prior year, as well as other factors, including compensation trends in the biopharmaceutical industry and among our benchmark peers.

Our compensation committee has delegated authority to our chief executive officer to make equity awards under our 2015 Plan to employees of the company or any of its affiliates in connection with hiring, promotions, employee recognition or exceptional performance, in each case, subject to certain limitations. In particular, our chief executive officer is not authorized to grant equity awards to: (i) an employee who is a senior vice president (or above) or a direct report to the chief executive officer; (ii) an employee who is an officer or director of the company or its subsidiaries and is subject to Section 16 of the Exchange Act; (iii) an employee who is at the time of grant, or who is anticipated to become during the term of the applicable equity award, a "covered employee," as defined in Section 162(m)(3) of the Internal Revenue Code of 1986, as amended, or the Internal Revenue Code; (iv) the chief executive officer; or (v) any other person whom our board of directors or compensation committee, respectively, may from time to time designate in writing as not being eligible to receive equity awards under the authority delegated to the chief executive officer. In addition, the number of shares underlying any equity awards granted by our chief executive officer must be within the range specified by our compensation committee for these awards, and the aggregate number of shares underlying equity awards that our chief executive officer may grant in any one calendar year or to any person in any one calendar year must be within specified limits established by our compensation committee. The exercise price of stock options must be equal to the closing price of our common stock on the Nasdaq Global Select Market on the date of grant, and all equity awards must have vesting terms consistent with those approved by our compensation committee. In addition, our chief executive officer is required to maintain a list of equity awards granted pursuant to such delegated authority and periodically report to our compensation committee regarding such awards.

With respect to any equity awards granted by our chief executive officer to new hires, our chief executive officer approves the awards in connection with such hires and, provides that the awards are generally to be granted to the

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new hires on the first day of the first or second calendar month following the date of such new hires' first date of employment, depending upon where that start date falls within the month. With respect to any equity awards granted by our chief executive officer to employees in connection with mid-year promotions, our chief executive officer approves the awards in connection with such promotions and provides that the awards are to be granted on July 1 of the applicable year.

Notwithstanding the delegation of authority to our chief executive officer to grant certain equity awards in connection with certain new hires and mid-year promotions, our compensation committee approves all equity awards that are a) granted under our 2020 Inducement Plan, as amended, or the 2020 Plan or 2015 Plan and b) in connection with annual promotions as part of our annual compensation review process.

ROLE OF MANAGEMENT

Our chief executive officer makes performance and compensation recommendations to our compensation committee for our other named executive officers and certain members of our executive team. Our chief executive officer's performance is evaluated and approved directly by the compensation committee, considering input from our board of directors. Evaluations of each of our named executive officers and other members of our executive team are based on our overall corporate performance against the annual goals approved by the board of directors at the beginning of each year and, in the case of executive officers other than our chief executive officer, the achievement of individual goals, as discussed in more detail below. The evaluation of our chief executive officer is based solely on our corporate performance goals, in recognition of her overall responsibility for our corporate performance and to incentivize the chief executive officer to drive the execution of our strategic plans and achievement of our corporate goals.

ROLE OF THE COMPENSATION CONSULTANT

The compensation committee has the sole authority to retain, at our expense, one or more third-party compensation consultants to assist it in performing its responsibilities. The compensation committee may terminate the services of the consultant if the compensation committee deems it appropriate. In 2023, the compensation committee utilized the services of Aon to assist it in fulfilling its responsibilities. Aon was retained exclusively by the compensation committee and has not been retained by management to perform any work for the company other than projects performed at the direction of the compensation committee. Aon provides analysis and recommendations regarding:

In addition, we subscribe to Aon's various global annual and specialized life sciences and general industry compensation surveys on an ongoing basis. Aon advises the compensation committee on all of the principal aspects of executive compensation, including executive new hire compensation arrangements. Upon request, Aon consultants attend meetings of the compensation committee, including executive sessions in which executive compensation issues are discussed. Aon reports to the compensation committee and not to management, although it meets with management for purposes of gathering information for its analyses and recommendations. The compensation committee annually evaluates its engagement of compensation consultants, and selected Aon to advise with respect to compensation matters based on Aon's industry experience and reputation, which our compensation committee concluded continues to give Aon useful context and knowledge to advise it. The compensation committee has assessed the independence of Aon pursuant to SEC and Nasdaq Listing Rules and concluded that no conflict of interest exists that would prevent Aon from independently advising the compensation committee.

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DEFINING AND COMPARING COMPENSATION TO MARKET BENCHMARKS

In evaluating the total compensation of our named executive officers, our compensation committee, using information provided by Aon, establishes a peer group of publicly traded companies in the biopharmaceutical and biotechnology industries that is selected based on a balance of the following criteria, of public companies:

Based on these criteria, our peer group for 2023 compensation setting, referred to as our 2023 peer group, as approved by our compensation committee, comprised the following 17 companies:

* Addition to 2023 peer group from the 2022 peer group; removed Acceleron Pharmaceuticals Inc. (following its November 2021 acquisition), Biohaven Pharmaceutical Holding Company Ltd., Nektar Therapeutics, and Sage Therapeutics, Inc.

The compensation committee believes the compensation practices of our 2023 peer group provide us with appropriate benchmarks for evaluating the compensation of our named executive officers. Such information provides useful context as well as a solid reference point for making decisions. Notwithstanding the similarities of our 2023 peer group to our company, due to the nature of our business, we compete for executive talent with many companies that are larger and more established than we are or that possess greater resources than we do, as well as with prestigious academic and non-profit institutions. Other considerations, including market factors, the experience level of the executive and the executive's performance against established corporate goals and individual objectives, may require that our compensation committee vary from its compensation practices or general compensation philosophy under certain circumstances. We believe that the compensation practices of our 2023 peer group provided us with appropriate benchmarks for evaluating the compensation of our named executive officers for 2023.

For purposes of compensation for 2024, our compensation committee, with the advice of Aon, examined our 2023 peer group in light of our continued growth throughout 2023, with reference to market capitalization, therapeutic area, stage of development, number of employees and other key business metrics, as well as whether the companies in our 2023 peer group suffered any clinical setbacks or experienced reduced growth. Based on these considerations, our compensation committee added the following two companies to our 2024 peer group - Deciphera Pharmaceuticals, Inc. and PTC Therapeutics, Inc. - and removed the following two companies that had been included in our 2023 peer group - Alnylam Pharmaceuticals, Inc. and United Therapeutics Corporation.

EXECUTIVE COMPENSATION ELEMENTS

As previously discussed above, the primary elements of our executive compensation program are base salary, annual performance-based cash incentives and equity incentive awards. Our compensation committee uses sound judgment to allocate long-term and short-term compensation for our named executive officers, in alignment with our pay-for-performance philosophy and the long-term interests of stockholders. After reviewing information provided

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by our compensation consultant and other relevant data, our compensation committee exercises its judgment to determine what it believes to be the appropriate level and mix of the various compensation components. We generally strive to provide our named executive officers with a balance of short-term and long-term incentives to encourage consistently strong performance. For more information, please see "Executive Compensation-Compensation Objectives and Philosophy."

In addition, we provide our executives with benefits that are available to all employees, including medical, vision and dental insurance; life and disability insurance; medical and dependent care flexible spending accounts; a 401(k) plan; and an opportunity to invest in our company pursuant to our 2015 Employee Stock Purchase Plan, or 2015 ESPP. We offer our executives severance benefits upon an involuntary or constructive termination, as we believe such post-employment compensation protections are appropriate in light of similar benefits available to executive officers at companies in our peer group. We also offer our executives additional severance benefits in connection with involuntary or constructive terminations after a change-in-control. We believe that reasonable and competitive change-in-control payments and benefits are an important part of an executive compensation program to attract and retain senior executives. We also believe such payments and benefits are in the best interests of our stockholders because they incentivize senior executives to continue to strive to achieve stockholder value in connection with change-in-control situations, particularly where the possibility of a change-in-control and the related uncertainty may lead to the departure or distraction of senior executives to the detriment of our company and our stockholders.

BASE SALARY

We use base salaries to recognize the experience, skills, knowledge and responsibilities required of all our employees, including our named executive officers. None of our named executive officers is currently party to an employment agreement or other agreement or arrangement that provides for automatic or scheduled increases in base salary. However, on an annual basis, our compensation committee reviews and evaluates, with input from our chief executive officer, the need for adjustment of the base salaries of our executive officers (other than our chief executive officer), and our compensation committee reviews and evaluates, without input from our chief executive officer, the need for adjustment of the base salary of our chief executive officer, in each case, based on among other things, changes and expected changes in the scope of an executive officer's responsibilities, including promotions, the individual contributions made by and performance of the executive officer during the prior year, the unique skills and experience of the executive officer, our overall growth and development as a company and general salary or other market trends in our industry.

In February 2023, our compensation committee approved salary increases for each of our named executive officers, effective January 2023, based on a review of market data provided by Aon, the compensation levels of our named executive officers, the company's performance against our 2022 corporate performance goals and, in the case of executive officers other than our chief executive officer, each executive officer's achievement of individual goals. The table below sets forth the adjustments to annualized base salary, in dollars and as a percentage, for each of our named executive officers:

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ANNUAL PERFORMANCE-BASED CASH INCENTIVES

Our board of directors has adopted the executive bonus plan, which provides for cash bonus payments to eligible executives based upon the annual attainment of performance targets established by the compensation committee for each executive during the first quarter of the applicable fiscal year. The payment targets are related to individual performance measures or objectives (other than for our chief executive officer), which we refer to as individual performance goals, and corporate financial and operational measures or objectives, which we refer to as corporate

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performance goals. Target award split between company and individual achievement for both the chief executive officer and our named executive officers is as follows:

We believe this executive bonus plan provides incentive that motivates and rewards achievement of performance goals that directly correlates to serving our mission to deliver for our patients and further our company objectives for the short- and long-term, which we believe will lead to the enhancement of stockholder value, consistent with our compensation philosophy.

Each executive officer participating in the executive bonus plan is assigned a target award opportunity for the performance period. Subject to the rights contained in any agreement between the executive officer and the company, an executive officer must remain employed by the company through the bonus payment date to be eligible to receive a bonus. The executive bonus plan also permits the compensation committee to approve additional bonuses to executive officers in its sole discretion, but the compensation committee did not approve any such additional bonuses in 2023. Each of our named executive officers is eligible to participate in the executive bonus plan. Our compensation committee caps annual cash incentive program payouts in any given year at 150% of the target payout level.

CORPORATE PERFORMANCE

Below is the list of the company's 2023 corporate performance goals and relative weighting assigned to each goal, which were approved by our board of directors and considered by our executive leadership team and compensation committee in their respective assessment of the company's achievement of corporate performance goals for 2023:

Enable a long-term positive impact for patients globally through the efficient, sustainable, and compliant execution of our business [relative weighting: 50%]

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Thoughtfully and urgently discover and develop transformative medicines that benefit broad patient populations with unmet need [relative weighting: 30%]

Sustain and reinforce our differentiated culture to attract and retain diverse and highly capable talent; and promote our leadership in precision medicine to expand our external engagements [relative weighting: 20%]

* These corporate performance goals include highly sensitive competitive data, including pre-clinical, clinical, regulatory and financial targets. We do not disclose these specific portions of our goals because we believe that such disclosure would result in competitive harm to us. We purposely set these goals at challenging levels. Revealing certain elements of these goals could potentially reveal insights about our pre-clinical, clinical, regulatory and strategic plans or objectives that our competitors or potential collaborators could use against us.

Based on the recommendation of our compensation committee (including the overachievement on some goals balanced against the underachievement of others), our board determined that our company achieved the 2023 corporate performance goals at 115%, as set forth in the table below.

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The individual objectives assigned in 2023 to our named executive officers other than our chief executive officer were as follows:

Michael Landsittel, M.B.A.

Mr. Landsittel was assigned objectives related to (1) expanding corporate presence and influence, both externally and internally, including strengthening external relationships with our sell-side analysts and embracing initiatives to further expand accessibility and influence inside the company and (2) ensuring the continued evolution of the finance, information systems & facilities functional capabilities and processes to meet the needs of the company as we continue to expand globally. For 2023, the compensation committee determined that Mr. Landsittel achieved 115% of his individual objectives.

Fouad Namouni, M.D.

Dr. Namouni was assigned objectives related to (1) enabling the research and development organization to support the avapritinib go-to-market execution and drive pipeline progress, and (2) increasing in-person engagement with major stockholders and potential new ones. For 2023 the compensation committee determined that Dr. Namouni achieved 118% of his individual objectives.

Christina Rossi, M.B.A.

Ms. Rossi was assigned objectives related to (1) delivering a strong indolent SM launch and cross-functional execution, enabling the company to meet or exceed 2023 revenue targets and broadening focus towards other corporate priorities, and (2) fostering a differentiated company culture, including increased engagement and

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motivation around company mission, vision and strategy. For 2023, the compensation committee determined that Ms. Rossi achieved 121% of her individual objectives.

Percy H. Carter, M.B.A., Ph.D.

Dr. Carter was assigned objectives related to (1) advancing the pipeline and platform and (2) continuing to increase internal and external engagement, including with scientific leadership and the investment community. For 2023 the compensation committee determined that Dr. Carter achieved 115% of his individual objectives.

Based on company and individual performance in 2023, the compensation committee approved the following cash incentive payments under the executive bonus plan for each of our named executive officers:

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EQUITY INCENTIVE AWARDS

We believe that equity grants provide our executives with a strong and direct connection to our long-term performance, create an ownership and performance culture and help to align the interests of our executives and our stockholders. In addition, we believe that equity grants with a time-based vesting feature promote executive retention and ultimately business continuity because this feature incentivizes our executive officers to remain in our employment during the vesting period. Accordingly, our compensation committee and board of directors periodically review the equity incentive compensation of our named executive officers and from time to time may grant equity incentive awards to them in the form of stock options, RSUs and PSUs.

Stock Options and RSUs

Equity compensation represents the largest at-risk component of our named executive officers' compensation arrangements. We believe it is appropriate to align the interests of our executives with those of our stockholders to achieve and sustain long-term stock price growth. For employees at or above the vice president level, including our executive officers, our compensation committee granted a combination of stock options and RSUs in connection with their annual equity awards at a fixed ratio. The compensation committee structured the mix of equity vehicles and the relative weight assigned to each type of award to motivate performance and drive stock price appreciation over the long-term through stock options, which deliver value only if the stock price increases, and to ensure some amount of value delivery through the RSUs, which are complementary because they have upside potential but deliver some value even if the stock price does not increase, while also reinforcing an ownership culture and commitment to our long-term success. We also expect to generally grant stock options and RSUs to executive officers in the form of initial grants upon new hire and on an annual basis in subsequent years. None of our named executive officers is currently party to an employment agreement that provides for an automatic equity award.

Any initial equity awards granted to executive officers in connection with the commencement of their employment, or new hire awards, are generally granted on the first day of the first or second calendar month following the date of such new hires' start date of regular employment depending upon the timing of such start date, and any annual equity awards granted to executive officers, or annual awards, are generally granted in the first quarter of the year following the applicable performance period. All stock options granted to our executive officers will: have an exercise price equal to the closing price of our common stock as reported on the Nasdaq Global Select Market on the date of grant; have time-based vesting; and expire ten years after the date of grant. New hire stock option awards vest as to 25% of the shares underlying the option on the first anniversary of the grant date and as to an additional 1/48th of the shares underlying the option monthly thereafter. Annual stock option awards vest monthly as to 1/48th of the shares underlying the option over four years, beginning on the one-month anniversary of the grant date. Upon a termination of employment (except due to death or disability), vesting for stock options granted to executive officers will generally cease and exercise rights will cease three months thereafter. Each RSU granted to our executive officers with time-based vesting will entitle the executive officer to one share of our common stock if and when the RSU vests. New hire RSU awards and any annual RSU awards vest as to 25% of the shares underlying the RSU award on the first anniversary of the grant date and as to an additional 25% of the shares

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underlying the RSU award annually thereafter. Except as described above, vesting for all stock options and RSUs is subject to the executive officer's continued employment or continued service as an employee, consultant or director with the company or any of its affiliates, as applicable, and will cease upon termination of employment or service relationship, as applicable (except due to death or disability). In specified termination and change-in-control circumstances, equity awards held by our named executive officers are subject to accelerated vesting. See "-Employment, Severance and Change-in-Control Arrangements" below for further information.

Performance-Based Restricted Stock Unit Program

Beginning in 2023, we introduced a PSU program for the members of our executive team, including our chief executive officer and other named executive officers. We adopted our PSU program to offer a new equity vehicle to help further align our executive officers' interests with those of our stockholders, encourage long-term performance, and create an additional retention tool and incentive for our named executive officers. Consistent with our pay-for-performance philosophy, the number of awardable PSUs can increase or decrease depending on the company's performance, and ranges from 0% - 200% of the PSU target. Therefore, there is no guarantee that PSUs will vest, reinforcing the significant performance-based nature of these awards.

The PSUs granted to our named executive officers in 2023 have a performance cycle of three calendar years and may be awarded contingent upon the performance of the company's relative total stockholder return, or rTSR, measured against the companies comprising the Standard & Poor's Biotech Industry Select Index, or the S&P Biotech Index, as of the first day of the performance cycle and that remain publicly traded for the duration of that cycle. For purposes of these PSU awards, the company rTSR is based on the total percentage return per share based on a 20-trading day average stock price beginning on the first trading day of the performance cycle and a 20-trading day average stock price ending on the last day of the performance cycle. The actual number of PSUs that can be earned is based on the company's rTSR performance as compared against the companies in the S&P Biotech Index as follows (with the percentage determined by linear interpolation for performance between the 25th and 100th percentiles):

If the company's rTSR is negative over the performance period, the payout will not exceed 100% of the target number even if the percentile rank exceeds the 50th percentile as compared to the S&P Biotech Index companies.

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Following the close of the three-year performance cycle, the board of directors or the compensation committee will determine and certify the number of PSUs that are awardable to each participating executive officer based on the above chart, known as the administrator determination. Awardable PSUs will vest on the third anniversary of the grant date contingent on the executive officer's continued service relationship through such date, or the grant vesting date. The three-year performance cycle and vesting period serve as additional retention tools and incentives for long-term sustained stock price performance to support long-term alignment with our stockholders.

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In the event the executive officer's service relationship ends due to death or disability prior to the administrator determination, the PSU award shall immediately vest and become payable in the amount of the target award; if such termination occurs after the administrator determination, the grant will vest and become payable in the amount of the previously certified awardable PSUs. If a sale event of the company (as defined in the PSU award agreement) occurs prior to the administrator determination, the board of directors or compensation committee will determine the number of awardable PSUs to be the higher of the target or actual award, multiplied by the payout percentage in the above chart based on the company's rTSR over a shortened performance cycle ending on the sale event date and using the sale price. However, such awardable PSUs will not vest until the grant vesting date, contingent on the executive officer's continued service relationship. If the executive officer's service relationship terminates without cause or for good reason (as such terms are defined in the PSU award agreement) within one year after a change in control event and prior to the grant vesting date, the outstanding awardable PSUs will immediately vest and become payable provided the executive officer signs a separation agreement with a release of claims that becomes effective and enforceable.

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Equity Awards to Executive Officers

In determining the size of the equity awards to our named executive officers, our compensation committee, with assistance from Aon, considers our company performance, individual performance, the potential for enhancing the creation of value for our stockholders, the company's broader organizational equity needs and overall dilution, as well as industry and peer group benchmark data. We evaluate our equity award program on an annual basis to ensure that it appropriately links to our long-term performance by aligning the interests of our executives and our stockholders, remains competitive with industry and peer benchmarks and is consistent with our overall equity needs and dilution levels.

In February 2023, our compensation committee granted stock options, RSUs and PSUs to our named executive officers in the amounts set forth in the table below.

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Health and Welfare Benefits

Our named executive officers are eligible to participate in all of our employee benefit plans, including our medical, dental, vision, life and disability insurance plans and commuting benefits plan, in each case, on the same basis as other employees.

401(k) Plan

We maintain a 401(k) plan that is intended to qualify under Section 401(k) of the Internal Revenue Code. In general, all of our employees, including our named executive officers, are eligible to participate in the 401(k) plan. Under the 401(k) plan, employees may elect to defer their current compensation up to the statutorily prescribed annual limit. We currently match 100% of the first 2%, and 50% of the next 4% of compensation contributed by an employee to the plan. Matching contributions are 100% vested immediately. Matching contributions made for each of our named executive officers in 2023 are included in the "2023 Summary Compensation Table" below.

Employee Stock Purchase Plan

Pursuant to our 2015 ESPP, employees, including our named executive officers, have an opportunity to purchase our common stock at a discount on a tax-qualified basis through payroll deductions. Our 2015 ESPP is designed to qualify as an "employee stock purchase plan" under Section 423 of the Internal Revenue Code. The purpose of our 2015 ESPP is to encourage our employees, including our named executive officers, to become our stockholders and better align their interests with those of our other stockholders.

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Perquisites

We do not provide perquisites or personal benefits to our named executive officers other than in connection with travel reimbursement and relocation assistance for new hires on a limited basis.

No Tax Gross-ups

We do not provide for any tax gross-up payments to our named executive officers other than in connection with the tax protection of certain relocation expenses.

OTHER COMPENSATION POLICIES AND PRACTICES

Clawback Policy

In 2023, we updated our clawback policy for the recoupment of incentive compensation paid after the policy's effective date to our current and former executive officers, whom we refer to as covered persons. The policy provides that if we are required to prepare a financial restatement, we are entitled to recover reasonably promptly all erroneously awarded compensation received by such covered person after the policy's effective date and during the three completed fiscal years immediately preceding the restatement date. For purposes of this policy, erroneously awarded compensation means incentive compensation, as defined in the policy, received by a covered

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person in excess of the amount that otherwise would have been received had the compensation been determined based on restated amounts in the financial restatement, without regard to any taxes paid. Our 2019 clawback policy remains in effect with respect to incentive compensation received prior to the effective date of our updated policy.

Stock Ownership Guidelines

In December 2020, our board of directors adopted stock ownership guidelines designed to ensure that our directors and executive officers are focused on both short- and long-term objectives and to better align their interests with other stockholders.

The guidelines provide that each of our chief executive officer and other named executive officers should achieve the ownership level associated with their position within five years from the date of the appointment as the chief executive officer or designation as a named executive officer, as the case may be. Each non-employee director is required to achieve the ownership level required for non-employee directors within five years from the date of their initial election to our board. The guidelines are determined in comparison to base salary as follows.

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When determining stock ownership levels, for 2022 we included shares beneficially owned, shares underlying restricted stock and RSUs (whether or not vested) and shares underlying "in-the-money" vested stock option awards. In April 2023, we amended and restated our stock ownership guidelines, eliminating shares underlying vested and unexercised "in-the-money" stock option awards from the calculation of requisite stock ownership levels for the covered parties. Unvested and unearned PSUs were also excluded from the calculation of such requisite stock ownership levels. As of December 31, 2023, our chief executive officer and other named executive officers and our non-employee directors had each satisfied the requirements of our stock ownership guidelines in effect as of that date (taking into account the April 2023 amendment and restatement of our stock ownership guidelines).

Insider Trading Policy

In 2024, the board of directors approved an amended and restated insider trading policy which can be found as Exhibit 19.1 of our Annual Report on Form 10-K for the fiscal year ended December 31, 2023. The policy expressly prohibits purchasing or selling any company securities (including, without limitation, a gift, loan, pledge or hedge, contribution to a trust, or any other sale or transfer, regardless of how the securities are held), while aware of material, non-public information concerning the company. The policy also includes pre-clearance procedures for our directors and certain employees, and disallows transactions designed to hedge or offset any decrease in the market value of the company's common stock.

Anti-Hedging and Pledging Policy

Our insider trading policy expressly prohibits all of our directors and employees, including our named executive officers, from engaging in speculative transactions in company common stock, including buying our securities on margin, borrowing against our securities held in a margin account, engaging in short sales of our securities, buying or selling derivatives on our securities or any other hedging transactions. Our insider trading policy prohibits all of our directors and employees, including our named executive officers, from pledging our securities as collateral for a loan.

TAX AND ACCOUNTING CONSIDERATIONS

We account for equity compensation paid to our employees under the rules of the Financial Accounting Standards Board Accounting Standards Codification Topic 718, or FASB ASC Topic 718, which rules require us to estimate and record an expense over the service period of any such award. Accounting rules also require us to record cash compensation as an expense at the time the obligation is accrued. To date, these accounting requirements have not impacted our executive compensation programs and practices.

Prior to January 1, 2018, when the Tax Cuts and Jobs Act of 2017, or the Tax Act, became effective, Section 162(m) of the Internal Revenue Code, or Section 162(m), generally limited to $1 million the deduction that a public company could claim in any tax year with respect to compensation paid to each of its chief executive officer and three other named executive officers whose compensation was required to be disclosed in the proxy statement

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(other than the chief financial officer), unless such compensation was performance-based as determined under the Section 162(m) regulations. Under the Tax Act, the performance-based compensation exception has been repealed, subject to certain transition rules. In addition, the deduction limitation now applies to anyone serving as the chief executive officer, the chief financial officer, and the top three other most highly compensated officers, and once an executive becomes a "covered employee" under Section 162(m), the individual will remain a "covered employee" forever (even after leaving the company, including after death). The new rules generally apply to taxable years beginning after December 31, 2017 but do not apply to compensation paid pursuant to a written binding contract in effect on November 2, 2017 that is not modified in any material respect after that date. As a result, for fiscal years beginning after December 31, 2017, all compensation in excess of $1 million paid to the specified executives will not be deductible, subject to the transition relief. On March 11, 2021, The American Rescue Plan Act of 2021, or ARPA, was signed into law to assist in the economic and health recovery brought on by the COVID-19 pandemic. Beginning on or after December 31, 2026, the ARPA expands the applicability of Section 162(m) to also include the next five highest paid corporate officers so that the total number of covered employees subject to the $1 million deduction limitation will be at least 10. In designing our executive compensation program and determining the compensation of our executive officers, including our named executive officers, our compensation committee considers a variety of factors, including the potential impact of the Section 162(m) deduction limit. However, to maintain flexibility to compensate our executive officers in a manner designed to promote our short-term and long-term corporate goals, our compensation committee has not adopted a policy that all compensation must be deductible. Our compensation committee believes that our stockholders' interests are best served if its discretion and flexibility in awarding compensation is not restricted, even though some compensation awards may result in non-deductible compensation expense.

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Report of the Compensation Committee of the Board of Directors

The compensation committee has reviewed and discussed the Compensation Discussion and Analysis required by Item 402(b) of Regulation S-K with our management. Based on this review and discussion, the compensation committee recommended to our board of directors that the Compensation Discussion and Analysis be included in this proxy statement.

This report of the compensation committee is not "soliciting material," shall not be deemed "filed" with the SEC and shall not be incorporated by reference by any general statement incorporating by reference this proxy statement into any filing under the Exchange Act, whether made before or after the date hereof and irrespective of any general incorporation language in any such filing, except to the extent that we specifically incorporate this information by reference, and shall not otherwise be deemed filed under such acts.

By the compensation committee of the board of directors of Blueprint Medicines Corporation.

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2023 SUMMARY COMPENSATION TABLE

The following table sets forth information regarding total compensation, for service rendered in all capacities, earned by or paid to each of our named executive officers during the years indicated.