Statement of Changes in Beneficial Ownership (Form 4)

Ownership Submission

FORM 4 Check this box if no longer subject to Section 16, Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * MPM BioVentures 2014, L.P. 2. Issuer Name and Ticker or Trading Symbol iTeos Therapeutics, Inc. [ITOS] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O MPM CAPITAL , 450 KENDALL STREET 3. Date of Earliest Transaction (Month/Day/Year) (Street) CAMBRIDGE MA 02142 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Join/Group Filing(Check Applicable Line) ___ Form filed by One Reporting Person _X_ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code 4. Securities Acquired (A) or Disposed of (D) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) 6. Ownership Form: Direct (D) or Indirect (I) 7. Nature of Indirect Beneficial Ownership Code V Amount (A) or (D) Price

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivate Security	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code	5. Number of Derivative Securities Acquired (A) or Disposed of (D)	6. Date Exercisable and Expiration Date	7. Title and Amount of Securities Underlying Derivative Security	8. Price of Derivative Security	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s)	10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)	11. Nature of Indirect Beneficial Ownership
Code	V	(A)	(D)	Date Exercisable	Expriation Date	Title	Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address	Relationships
Director	10% Owner	Officer	Other
MPM BioVentures 2014, L.P. C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE, MA02142		X
EVNIN LUKE C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE, MA02142		X
Foley Todd C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE, MA02142		X
MPM BioVentures 2014 (B), L.P. C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE, MA02142		X
MPM Asset Management Investors BV2014 LLC C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE, MA02142		X
MPM BioVentures 2014 LLC C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE, MA02142		X
MPM BioVentures 2014 GP LLC C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE, MA02142		X
MPM BIOVENTURES 2018 (B), L.P. C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE, MA02142		X
MPM ASSET MANAGEMENT INVESTORS BV2018 LLC C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE, MA02142		X

Signatures

/s/ Ansbert Gadicke, managing director of MPM BioVentures 2014 LLC, the managing member of MPM BioVentures 2014 GP LLC, the general partner of MPM BioVentures 2014, L.P.	2021-12-07
**Signature of Reporting Person	Date
/s/ Luke Evnin	2021-12-07
**Signature of Reporting Person	Date
/s/ Todd Foley	2021-12-07
**Signature of Reporting Person	Date
/s/ Ansbert Gadicke, managing director of MPM BioVentures 2014 LLC, the managing member of MPM BioVentures 2014 GP LLC, the general partner of MPM BioVentures 2014 (B), L.P.	2021-12-07
**Signature of Reporting Person	Date
/s/ Ansbert Gadicke, managing director of MPM BioVentures 2014 LLC, the manager of MPM Asset Management Investors BV2014 LLC	2021-12-07
**Signature of Reporting Person	Date
/s/ Ansbert Gadicke, managing director of MPM BioVentures 2014 LLC	2021-12-07
**Signature of Reporting Person	Date
/s/ Ansbert Gadicke, managing director of MPM BioVentures 2014 LLC, the managing member of MPM BioVentures 2014 GP LLC	2021-12-07
**Signature of Reporting Person	Date
/s/ Ansbert Gadicke, managing director of MPM BioVentures 2018 LLC, the managing member of MPM BioVentures 2018 GP LLC, the general partner of MPM BioVentures 2018 (B), L.P.	2021-12-07
**Signature of Reporting Person	Date
/s/ Ansbert Gadicke, managing director of MPM BioVentures 2018 LLC, the manager of MPM Asset Management Investors BV2018 LLC	2021-12-07
**Signature of Reporting Person	Date

Explanation of Responses:

(*)	If the form is filed by more than one reporting person, see Instruction 5(b)(v).
(**)	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Transaction effected pursuant to a plan established pursuant to Rule 10b5-1.
(2)	The shares were sold as follows: 10,467 by MPM BioVentures 2014, L.P. ("BV 2014"), 359 by MPM Asset Management Investors BV2014 LLC ("AM BV2014"), 6,612 by MPM BioVentures 2018, L.P. ("BV 2018") and 131 by MPM Asset Management Investors BV2018 LLC ("AM BV2018"). MPM BioVentures 2014 GP LLC and MPM BioVentures 2014 LLC ("BV 2014 LLC") are the direct and indirect general partners of BV 2014 and BV 2014(B). BV 2014 LLC is the manager of AM BV2014. MPM BioVentures 2018 GP LLC and MPM BioVentures 2018 LLC ("BV 2018 LLC") are the direct and indirect general partners of BV 2018 and BV 2018(B). BV 2018 LLC is the manager of AM BV2018. Messrs. Evnin and Foley are managing directors of BV 2014 LLC and BV 2018 LLC.
(3)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $34.15 to $35.135 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.
(4)	The shares are held as follows: 1,651,193 by BV 2014, 97,289 by, 56,834 by AM BV2014, 1,042,857 by BV 2018, 48,966 by BV 2018(B) and 20,593 by AM BV2018. Each of the Reporting Persons disclaims beneficial ownership of the securities herein except to the extent of his or its respective pecuniary interest therein, if any.
(5)	The shares were sold as follows: 1,441 by BV 2014, 50 by AM BV2014, 910 by BV 2018 and 18 by AM BV2018.
(6)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $35.15 to $36.06 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.
(7)	The shares are held as follows: 1,649,752 by BV 2014, 97,289 by BV 2014(B), 56,784 by AM BV2014, 1,041,947 by BV 2018, 48,966 by BV 2018(B) and 20,575 by AM BV2018. Each of the Reporting Persons disclaims beneficial ownership of the securities herein except to the extent of his or its respective pecuniary interest therein, if any.
(8)	The shares were sold as follows: 107 by BV 2014, 4 by AM BV2014, 67 by BV 2018 and 1 by AM BV2018.
(9)	The shares are held as follows: 1,649,645 by BV 2014, 97,289 by BV 2014(B), 56,780 by AM BV2014, 1,041,880 by BV 2018, 48,966 by BV 2018(B) and 20,574 by AM BV2018. Each of the Reporting Persons disclaims beneficial ownership of the securities herein except to the extent of his or its respective pecuniary interest therein, if any.
(10)	The shares were sold as follows: 5,046 by BV 2014, 173 by AM BV2014, 3,187 by BV 2018 and 63 by AM BV2018.
(11)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $31.98 to $32.975 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.
(12)	The shares are held as follows: 1,644,599 by BV 2014, 97,289 by BV 2014(B), 56,607 by AM BV2014, 1,038,693 by BV 2018, 48,966 by BV 2018(B) and 20,511 by AM BV2018. Each of the Reporting Persons disclaims beneficial ownership of the securities herein except to the extent of his or its respective pecuniary interest therein, if any.
(13)	The shares were sold as follows: 698 by BV 2014, 24 by AM BV2014, 441 by BV 2018 and 8 by AM BV2018.
(14)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $32.99 to $33.98 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.
(15)	The shares are held as follows: 1,643,901 by BV 2014, 97,289 by BV 2014(B), 56,583 by AM BV2014, 1,038,252 by BV 2018, 48,966 by BV 2018(B) and 20,503 by AM BV2018. Each of the Reporting Persons disclaims beneficial ownership of the securities herein except to the extent of his or its respective pecuniary interest therein, if any.
(16)	The shares were sold as follows: 303 by BV 2014, 10 by AM BV2014, 191 by BV 2018 and 4 by AM BV2018.
(17)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $34.00 to $34.125 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.
(18)	The shares are held as follows: 1,643,598 by BV 2014, 97,289 by BV 2014(B), 56,573 by AM BV2014, 1,038,061 by BV 2018, 48,966 by BV 2018(B) and 20,499 by AM BV2018. Each of the Reporting Persons disclaims beneficial ownership of the securities herein except to the extent of his or its respective pecuniary interest therein, if any.
(19)	The shares were sold as follows: 35 by BV 2014, 2 by AM BV2014, 22 by BV 2018 and 1 by AM BV2018.
(20)	The shares are held as follows: 1,643,563 by BV 2014, 97,289 by BV 2014(B), 56,571 by AM BV2014, 1,038,039 by BV 2018, 48,966 by BV 2018(B) and 20,498 by AM BV2018. Each of the Reporting Persons disclaims beneficial ownership of the securities herein except to the extent of his or its respective pecuniary interest therein, if any.
(21)	The shares were sold as follows: 10,701 by BV 2014, 368 by AM BV2014, 6,759 by BV 2018 and 134 by AM BV2018.
(22)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $32.84 to $33.75 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.
(23)	The shares are held as follows: 1,632,862 by BV 2014, 97,289 by BV 2014(B), 56,203 by AM BV2014, 1,031,280 by BV 2018, 48,966 by BV 2018(B) and 20,364 by AM BV2018. Each of the Reporting Persons disclaims beneficial ownership of the securities herein except to the extent of his or its respective pecuniary interest therein, if any.
(24)	The shares were sold as follows: 890 by BV 2014, 31 by AM BV2014, 562 by BV 2018 and 11 by AM BV2018.
(25)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $33.875 to $34.25 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.
(26)	The shares are held as follows: 1,631,972 by BV 2014, 97,289 by BV 2014(B), 56,172 by AM BV2014, 1,030,718 by BV 2018, 48,966 by BV 2018(B) and 20,353 by AM BV2018. Each of the Reporting Persons disclaims beneficial ownership of the securities herein except to the extent of his or its respective pecuniary interest therein, if any.

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