# EDGAR Filing Document

**Accession Number:** 0001622229
**File Stem:** 0001193805-25-001001
**Filing Date:** 2025-7
**Character Count:** 15002
**Document Hash:** 4c4cb5032c1f89d96853417ab0f59a63
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193805-25-001001.hdr.sgml**: 20250711

**ACCESSION NUMBER**: 0001193805-25-001001

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13G

**PUBLIC DOCUMENT COUNT**: 3

**FILED AS OF DATE**: 20250711

**DATE AS OF CHANGE**: 20250711

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Cogent Biosciences, Inc.
- **CENTRAL INDEX KEY:** 0001622229
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 465308248
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13G
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-90431
- **FILM NUMBER:** 251117560

**BUSINESS ADDRESS:**
- **STREET 1:** 275 WYMAN STREET
- **STREET 2:** 3RD FLOOR
- **CITY:** WALTHAM
- **STATE:** MA
- **ZIP:** 02451
- **BUSINESS PHONE:** 617-945-5576

**MAIL ADDRESS:**
- **STREET 1:** 275 WYMAN STREET
- **STREET 2:** 3RD FLOOR
- **CITY:** WALTHAM
- **STATE:** MA
- **ZIP:** 02451

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Unum Therapeutics Inc.
- **DATE OF NAME CHANGE:** 20180402

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Unum Therapeutics, Inc.
- **DATE OF NAME CHANGE:** 20141014
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Flynn James E
- **CENTRAL INDEX KEY:** 0001352546

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13G

**MAIL ADDRESS:**
- **STREET 1:** 780 THIRD AVENUE
- **STREET 2:** 37TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10017

## Ex-99.A

Exhibit A

Joint Filing Agreement

The undersigned agree that this Schedule 13G, and all amendments thereto, relating to the Common Stock of Cogent Biosciences, Inc. shall be filed on behalf of the undersigned.

DEERFIELD MGMT, L.P.

By: J.E. Flynn Capital, LLC, General Partner

By: <u>Jonathan Isler</u>

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Jonathan Isler, Attorney-In-Fact

DEERFIELD MANAGEMENT COMPANY, L.P.

By: Deerfield UGP, LLC, General Partner

By: <u>Jonathan Isler</u>

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Jonathan Isler, Attorney-In-Fact

DEERFIELD PARTNERS, L.P.

By: Deerfield Mgmt, L.P., General Partner

By: J.E. Flynn Capital, LLC, General Partner

By: <u>Jonathan Isler</u>

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Jonathan Isler, Attorney-In-Fact

JAMES E. FLYNN

<u>/s/ Jonathan Isler</u>

Jonathan Isler, Attorney-In-Fact

## Ex-99.B

Exhibit B

Due to the relationships between them, the reporting persons hereunder may be deemed to constitute a "group" with one another for purposes of Section 13(d)(3) of the Securities Exchange Act of 1934.

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## SCHEDULE 13G

### Under the Securities Exchange Act of 1934

**Issuer:** Cogent Biosciences, Inc.

**Title of Class of Securities:** Common Stock

**CUSIP Number:** 19240Q201

**Date of Event Which Requires Filing of this Statement:** 07/07/2025

**Check the appropriate box to designate the rule pursuant to which this Schedule is filed:**

- [ ] Rule 13d-1(b)

- [x] Rule 13d-1(c)

- [ ] Rule 13d-1(d)

---

| 1. | Names of Reporting Persons<br>Deerfield Mgmt, L.P. | Names of Reporting Persons<br>Deerfield Mgmt, L.P. |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>DE | Citizenship or Place of Organization<br>DE |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>9053118.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>9053118.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>0.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>9053118.00 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>9053118.00 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>6.49% | Percent of Class Represented by Amount in Row (9)<br>6.49% |
| 12. | Type of Reporting Person (See Instructions)<br>PN | Type of Reporting Person (See Instructions)<br>PN |

**Comment for Type of Reporting Person:** Comprised of shares of common stock held by Deerfield Partners, L.P., of which Deerfield Mgmt, L.P. is the general partner.

---

| 1. | Names of Reporting Persons<br>Deerfield Management Company, L.P. | Names of Reporting Persons<br>Deerfield Management Company, L.P. |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>DE | Citizenship or Place of Organization<br>DE |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>9053118.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>9053118.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>0.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>9053118.00 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>9053118.00 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>6.49% | Percent of Class Represented by Amount in Row (9)<br>6.49% |
| 12. | Type of Reporting Person (See Instructions)<br>PN | Type of Reporting Person (See Instructions)<br>PN |

**Comment for Type of Reporting Person:** Comprised of shares of common stock held by Deerfield Partners, L.P. of which Deerfield Management Company, L.P. is the investment advisor.

---

| 1. | Names of Reporting Persons<br>Deerfield Partners, L.P. | Names of Reporting Persons<br>Deerfield Partners, L.P. |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>DE | Citizenship or Place of Organization<br>DE |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>9053118.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>9053118.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>0.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>9053118.00 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>9053118.00 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>6.49% | Percent of Class Represented by Amount in Row (9)<br>6.49% |
| 12. | Type of Reporting Person (See Instructions)<br>PN | Type of Reporting Person (See Instructions)<br>PN |

---

| 1. | Names of Reporting Persons<br>James E. Flynn | Names of Reporting Persons<br>James E. Flynn |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>X1 | Citizenship or Place of Organization<br>X1 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>9053118.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>9053118.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>0.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>9053118.00 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>9053118.00 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>6.49% | Percent of Class Represented by Amount in Row (9)<br>6.49% |
| 12. | Type of Reporting Person (See Instructions)<br>IN | Type of Reporting Person (See Instructions)<br>IN |

**Comment for Type of Reporting Person:** Comprised of shares of common stock held by Deerfield Partners, L.P.

---

**Item 1(a). Name of Issuer:**
Cogent Biosciences, Inc.

**Item 1(b). Address of Issuer's Principal Executive Offices:**
275 Wyman Street, 3rd Floor, Waltham, Massachusetts 02451

**Item 2(a). Name of Person Filing:**
James E. Flynn, Deerfield Mgmt, L.P., Deerfield Management Company, L.P. and Deerfield Partners, L.P.

**Item 2(b). Address of Principal Business Office:**
James E. Flynn, Deerfield Mgmt, L.P., Deerfield Management Company, L.P. and Deerfield Partners, L.P., 345 Park Avenue South, 12th Floor, New York, NY 10010

**Item 2(c). Citizenship:**
Deerfield Mgmt, L.P., Deerfield Management Company, L.P. and Deerfield Partners, L.P. - Delaware limited partnerships;

James E. Flynn - United States citizen

**Item 2(d). Title of Class of Securities:**
Common Stock

**Item 2(e). CUSIP Number:**
19240Q201

**Item 3. If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:**

(a) [ ] Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o).

(b) [ ] Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c).

(c) [ ] Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c).

(d) [ ] Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8).

(e) [ ] An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);

(f) [ ] An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);

(g) [ ] A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);

(h) [ ] A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);

(i) [ ] A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);

(j) [ ] A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), if filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:

(k) [ ] Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).

**Item 4. Ownership:**

**(a) Amount beneficially owned:**

Deerfield Mgmt, L.P. - 9,053,118 shares
Deerfield Management Company, L.P. - 9,053,118 shares
Deerfield Partners, L.P. - 9,053,118 shares
James E. Flynn - 9,053,118 shares

**(b) Percent of class:**

Deerfield Mgmt, L.P. - 6.49%
Deerfield Management Company, L.P. - 6.49%
Deerfield Partners, L.P. - 6.49%
James E. Flynn - 6.49%

**(c) Number of shares as to which the person has:**

**(i) Sole power to vote or to direct the vote:**

All Reporting Persons - 0

**(ii) Shared power to vote or to direct the vote:**

Deerfield Mgmt, L.P. - 9,053,118
Deerfield Management Company, L.P. - 9,053,118
Deerfield Partners, L.P. - 9,053,118
James E. Flynn - 9,053,118

**(iii) Sole power to dispose or to direct the disposition of:**

All Reporting Persons - 0

**(iv) Shared power to dispose or to direct the disposition of:**

Deerfield Mgmt, L.P. - 9,053,118
Deerfield Management Company, L.P. - 9,053,118
Deerfield Partners, L.P. - 9,053,118
James E. Flynn - 9,053,118

**Item 5. Ownership of Five Percent or Less of a Class.**

[x] If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following.

**Item 6. Ownership of More than 5 Percent on Behalf of Another Person.**

Not Applicable

**Item 7. Identification and Classification of the Subsidiary**

Not Applicable

**Item 8. Identification and Classification of Members of the Group**

See Exhibit B

**Item 9. Notice of Dissolution of Group**

Not Applicable

**Item 10. Certification:**

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.

### SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Deerfield Mgmt, L.P.**

**Date:** 07/11/2025

**By:** /s/ Jonathan Isler

**Name & Title:** Jonathan Isler, Attorney-In-Fact

**Deerfield Management Company, L.P.**

**Date:** 07/11/2025

**By:** /s/ Jonathan Isler

**Name & Title:** Jonathan Isler, Attorney-In-Fact

**Deerfield Partners, L.P.**

**Date:** 07/11/2025

**By:** /s/ Jonathan Isler

**Name & Title:** Jonathan Isler, Attorney-In-Fact

**James E. Flynn**

**Date:** 07/11/2025

**By:** /s/ Jonathan Isler

**Name & Title:** Jonathan Isler, Attorney-In-Fact