Statement of Changes in Beneficial Ownership (4)

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. 20549
STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES
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Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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 __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below)
(Last) (First) (Middle) C/O MPM CAPITAL, 450 KENDALL STREET	3. Date of Earliest Transaction (MM/DD/YYYY) 11/17/2021
(Street) CAMBRIDGE, MA 02142 (City) (State) (Zip)	4. If Amendment, Date Original Filed (MM/DD/YYYY)	6. Individual or Joint/Group Filing (Check Applicable Line) ___ Form filed by One Reporting Person _ X _ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. Code (Instr. 8)		4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	11/17/2021		J⁽¹⁾		15671 ⁽²⁾	D	$0.00	3119320	I	See Footnote ⁽³⁾
Common Stock	11/22/2021		S⁽⁴⁾		9307 ⁽⁵⁾	D	$37.16 ⁽⁶⁾	3110013	I	See Footnote ⁽⁷⁾
Common Stock	11/22/2021		S⁽⁴⁾		11807 ⁽⁸⁾	D	$37.81 ⁽⁹⁾	3098206	I	See Footnote ⁽¹⁰⁾
Common Stock	11/23/2021		S⁽⁴⁾		19645 ⁽¹¹⁾	D	$36.21 ⁽¹²⁾	3078561	I	See Footnote ⁽¹³⁾
Common Stock	11/23/2021		S⁽⁴⁾		359 ⁽¹⁴⁾	D	$36.50 ⁽¹⁵⁾	3078202	I	See Footnote ⁽¹⁶⁾
Common Stock	11/24/2021		S⁽⁴⁾		4868 ⁽¹⁷⁾	D	$35.20 ⁽¹⁸⁾	3073334	I	See Footnote ⁽¹⁹⁾
Common Stock	11/24/2021		S⁽⁴⁾		18343 ⁽²⁰⁾	D	$36.05 ⁽²¹⁾	3054991	I	See Footnote ⁽²²⁾
Common Stock	11/24/2021		S⁽⁴⁾		13126 ⁽²³⁾	D	$37.02 ⁽²⁴⁾	3041865	I	See Footnote ⁽²⁵⁾

*Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)*
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)			11. Nature of Indirect Beneficial Ownership (Instr. 4)

Explanation of Responses:
(1)	Represents a pro rata in-kind distribution from MPM BioVentures 2014(B), L.P. ("BV 2014(B)") and MPM BioVentures 2018(B), L.P. ("BV 2018(B)") to its respectve limited partners for no consideration.
(2)	The shares were distributed as follows: 10,424 by BV 2014(B) and 5,247 by BV 2018(B).
(3)	The shares are held as follows: 1,771,303 by MPM BioVentures 2014, L.P. ("BV 2014"), 97,289 by BV2014(B), 60,967 by MPM Asset Management Investors BV2014 LLC ("AM BV2014"), 1,118,717 by MPM BioVentures 2018, L.P. ("BV 2018"), 48,966 by BV 2018(B) and 22,078 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. 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.
(4)	Transaction effected pursuant to a plan established pursuant to Rule 10b5-1.
(5)	The shares were sold as follows: 5,545 by BV 2014, 191 by AM BV2014, 3,502 by BV 2018 and 69 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 $36.58 to $37.555 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: 1,765,758 by BV 2014, 97,289 by, 60,776 by AM BV2014, 1,115,215 by BV 2018, 48,966 by BV 2018(B) and 22,009 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: 7,034 by BV 2014, 242 by AM BV2014, 4,443 by BV 2018 and 88 by AM BV2018.
(9)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $37.58 to $38.16 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.
(10)	The shares are held as follows: 1,758,724 by BV 2014, 97,289 by BV 2014(B), 60,534 by AM BV2014, 1,110,772 by BV 2018, 48,966 by BV 2018(B) and 21,921 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.
(11)	The shares were sold as follows: 11,704 by BV 2014, 403 by AM BV2014, 7,392 by BV 2018 and 146 by AM BV2018.
(12)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $35.46 to $36.45 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.
(13)	The shares are held as follows: 1,747,020 by BV 2014, 97,289 by BV 2014(B), 60,131 by AM BV2014, 1,103,380 by BV 2018, 48,966 by BV 2018(B) and 21,775 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.
(14)	The shares were sold as follows: 214 by BV 2014, 7 by AM BV2014, 135 by BV 2018 and 3 by AM BV2018.
(15)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $36.48 to $36.52 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.
(16)	The shares are held as follows: 1,746,806 by BV 2014, 97,289 by BV 2014(B), 60,124 by AM BV2014, 1,103,245 by BV 2018, 48,966 by BV 2018(B) and 21,772 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.
(17)	The shares were sold as follows: 2,900 by BV 2014, 100 by AM BV2014, 1,832 by BV 2018 and 36 by AM BV2018.
(18)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $34.82 to $35.78 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.
(19)	The shares are held as follows: 1,743,906 by BV 2014, 97,289 by BV 2014(B), 60,024 by AM BV2014, 1,101,413 by BV 2018, 48,966 by BV 2018(B) and 21,736 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.
(20)	The shares were sold as follows: 10,929 by BV 2014, 376 by AM BV2014, 6,902 by BV 2018 and 136 by AM BV2018.
(21)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $35.83 to $36.81 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.
(22)	The shares are held as follows: 1,732,977 by BV 2014, 97,289 by BV 2014(B), 59,648 by AM BV2014, 1,094,511 by BV 2018, 48,966 by BV 2018(B) and 21,600 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.
(23)	The shares were sold as follows: 7,820 by BV 2014, 269 by AM BV2014, 4,939 by BV 2018 and 98 by AM BV2018.
(24)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $36.85 to $37.27 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.
(25)	The shares are held as follows: 1,725,157 by BV 2014, 97,289 by BV 2014(B), 59,379 by AM BV2014, 1,089,572 by BV 2018, 48,966 by BV 2018(B) and 21,502 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.

Remarks:
See Form 4 for MPM BioVentures 2018, L.P for additional members of this joint filing.

Reporting Owners
Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
MPM BioVentures 2014, L.P. C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE, MA 02142		X
EVNIN LUKE C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE, MA 02142		X
Foley Todd C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE, MA 02142		X
MPM BioVentures 2014 (B), L.P. C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE, MA 02142		X
MPM Asset Management Investors BV2014 LLC C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE, MA 02142		X
MPM BioVentures 2014 LLC C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE, MA 02142		X
MPM BioVentures 2014 GP LLC C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE, MA 02142		X
MPM BIOVENTURES 2018 (B), L.P. C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE, MA 02142		X
MPM ASSET MANAGEMENT INVESTORS BV2018 LLC C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE, MA 02142		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.		11/24/2021
^**Signature of Reporting Person		Date
/s/ Luke Evnin		11/24/2021
^**Signature of Reporting Person		Date
/s/ Todd Foley		11/24/2021
^**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.		11/24/2021
^**Signature of Reporting Person		Date
/s/ Ansbert Gadicke, managing director of MPM BioVentures 2014 LLC, the manager of MPM Asset Management Investors BV2014 LLC		11/24/2021
^**Signature of Reporting Person		Date
/s/ Ansbert Gadicke, managing director of MPM BioVentures 2014 LLC		11/24/2021
^**Signature of Reporting Person		Date
/s/ Ansbert Gadicke, managing director of MPM BioVentures 2014 LLC, the managing member of MPM BioVentures 2014 GP LLC		11/24/2021
^**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.		11/24/2021
^**Signature of Reporting Person		Date
/s/ Ansbert Gadicke, managing director of MPM BioVentures 2018 LLC, the manager of MPM Asset Management Investors BV2018 LLC		11/24/2021
^**Signature of Reporting Person		Date