Sec Form 4 Filing - Venrock Associates VII, L.P. @ Cyteir Therapeutics, Inc. - 2021-06-22

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 Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Venrock Associates VII, L.P. 2. Issuer Name and Ticker or Trading Symbol Cyteir Therapeutics, Inc. [ CYT] 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 VENROCK, 3340 HILLVIEW AVENUE 3. Date of Earliest Transaction (MM/DD/YY) 06/22/2021 (Street) PALO ALTO, CA94304 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/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 (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction 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) Code V Amount (A) or (D) Price Common Stock 06/22/2021 C 3,259,025 A 3,259,025 I By Funds ( 2 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Series B Convertible Preferred Stock ( 1 ) 06/22/2021 C 10,000,000 ( 1 ) ( 1 ) Common Stock 2,933,583 ( 1 ) 0 D Series C Convertible Preferred Stock ( 1 ) 06/22/2021 C 1,109,368 ( 1 ) ( 1 ) Common Stock 325,442 ( 1 ) 0 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Venrock Associates VII, L.P. C/O VENROCK 3340 HILLVIEW AVENUE PALO ALTO, CA94304 X Venrock Partners VII, L.P. C/O VENROCK 3340 HILLVIEW AVENUE PALO ALTO, CA94304 X Venrock Management VII, LLC C/O VENROCK 3340 HILLVIEW AVENUE PALO ALTO, CA94304 X Signatures /s/ David L. Stepp, Authorized Signatory 06/23/2021 Signature of Reporting Person Date David L. Stepp, Authorized Signatory 06/23/2021 Signature of Reporting Person Date David L. Stepp, Authorized Signatory 06/23/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Each share of Series B Convertible Preferred Stock and Series C Convertible Preferred Stock converted into shares of Common Stock at a ratio of 1:3.4088 upon completion of the Issuer's initial public offering. The shares have no expiration date. ( 2 )Consists of 3,009,710 shares of Common Stock held by Venrock Associates VII, L.P. ("VA VII") and 249,315 shares of Common Stock held by Venrock Partners VII, L.P. ("VP VII"). Venrock Management VII, LLC ("VM VII") is the sole general partner of VA VII and VP VII and may be deemed to beneficially own these shares and expressly disclaims beneficial ownership over all shares held by VA VII and VP VII except to the extent of its indirect pecuniary interest therein.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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