# EDGAR Filing Document

**Accession Number:** 0001202769
**File Stem:** 0001193125-25-280813
**Filing Date:** 2025-11
**Character Count:** 10817
**Document Hash:** 5df5ae0de71c16afeabaa9e9f9348e06
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-25-280813.hdr.sgml**: 20251113

**ACCESSION NUMBER**: 0001193125-25-280813

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20251113

**FILED AS OF DATE**: 20251113

**DATE AS OF CHANGE**: 20251113

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** BERNS PAUL L
- **CENTRAL INDEX KEY:** 0001202769

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-42489
- **FILM NUMBER:** 251480727

**MAIL ADDRESS:**
- **STREET 1:** C/O NEUMORA THERAPEUTICS, INC.
- **STREET 2:** 260 ARSENAL PLACE, SUITE 1
- **CITY:** WATERTOWN
- **STATE:** MA
- **ZIP:** 02472
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Metsera, Inc.
- **CENTRAL INDEX KEY:** 0002040807
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 3 WORLD TRADE CENTER
- **STREET 2:** 175 GREENWICH STREET
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10007
- **BUSINESS PHONE:** (212) 784-6595

**MAIL ADDRESS:**
- **STREET 1:** 3 WORLD TRADE CENTER
- **STREET 2:** 175 GREENWICH STREET
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10007

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

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

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

[ ] Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>BERNS PAUL L<br><sub>(Last) (First) (Middle)</sub><br>C/O METSERA, INC. 3 WORLD TRADE<br>CENTER 175 GREENWICH STREET<br><sub>(Street)</sub><br>NEW YORK, NY 10007<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2025-11-13 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [ ] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>Metsera, Inc. [ MTSR ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[X] Form filed by One Reporting Person<br>[ ] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| Common Stock | 2025-11-13 |  | D<sup>(1)(2)</sup> |  | 4031 | D | <sup>(1)(2)(5)</sup> | 0 | D |  |
| Common Stock | 2025-11-13 |  | D<sup>(1)(2)</sup> |  | 7523682 | D | <sup>(1)(2)</sup> | 0 | I | See footnote<sup>(8)</sup> |
| Common Stock | 2025-11-13 |  | D<sup>(1)(2)</sup> |  | 8313680 | D | <sup>(1)(2)</sup> | 0 | I | See footnote<sup>(8)</sup> |
| Common Stock | 2025-11-13 |  | D<sup>(1)(2)</sup> |  | 957559 | D | <sup>(1)(2)</sup> | 0 | D |  |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| Restricted Stock Unit | $0 | 2025-11-13 |  | A |  | 4031 |  | <sup>(5)</sup> | <sup>(5)</sup> | Common Stock | 4031 | <sup>(5)</sup> | 4031 | D |  |
| Stock Option (right to buy)<sup>(3)(4)</sup> | $29.25 | 2025-11-13 |  | D |  |  | 24188 | <sup>(6)</sup> | 2035-05-19 | Common Stock | 24188 | <sup>(3)(4)</sup> | 0 | D |  |
| Stock Option (right to buy)<sup>(3)(4)</sup> | $8.18 | 2025-11-13 |  | D |  |  | 223430 | <sup>(7)</sup> | 2034-11-11 | Common Stock | 223430 | <sup>(3)(4)</sup> | 0 | D |  |

---

### Footnotes:

(1) Pursuant to the Agreement and Plan of Merger dated September 21, 2025, as amended on November 7, 2025 (the "Merger Agreement"), by and among Metsera, Inc. (the "Company"), Pfizer Inc., a Delaware corporation ("Parent"), and Mayfair Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of the Parent (the "Merger Sub"), the Merger Sub merged with and into the Company, with the Company continuing as the surviving corporation and a wholly owned subsidiary of the Parent (the "Merger").  At the Effective Time of the Merger (as defined in the Merger Agreement), each issued and outstanding share of common stock, par value $01 per share of the Company (the "Common Stock") was converted automatically into the right to receive (i) cash in an amount equal to $65.60 per share without interest (the "Closing Amount"), net of all applicable withholding taxes, plus

(2) (Continued from footnote 1) (ii) one contractual contingent value right representing the right to receive contingent payments (a "CVR") in cash, without interest, upon the achievement of certain specified milestones, in accordance with the terms and conditions of the contingent value rights agreement entered into by the Parent and Equiniti Trust Company, LLC, dated November 13, 2025 (collectively, the "Merger Consideration").

(3) Pursuant to the Merger Agreement, each outstanding and unexercised option immediately prior to the Effective Time, whether vested or unvested, was cancelled in exchange for the right to receive (x) an amount in cash equal to the product of (i) the excess, if any, of the Closing Amount minus the exercise price of such option, multiplied by (ii) the number of shares of Common Stock subject to such option immediately prior to the Effective Time, net of all applicable withholding taxes, and (y) one CVR for each share of the Common Stock subject to such stock option immediately prior to the Effective Time.  In the case of any unvested stock options, the cash payment and the CVRs are subject to the same vesting schedule terms as were applicable to the stock options,

(4) (Continued from footnote 3) except that all such payments will become vested upon the first anniversary of the closing of the Merger, subject to the holder's continued service with the Parent or its subsidiaries through the first anniversary of the Merger.

(5) On November 12, 2025, the Reporting Person was granted restricted stock units ("RSUs") under the Company's 2025 Incentive Award Plan in a transaction exempt under Rule 16b-3. Each RSU represents a contingent right to receive one share of Common Stock.  The RSUs vest in 36 substantially equal monthly installments from November 12, 2025.  Pursuant to the Merger Agreement, all RSUs were cancelled and converted into the right to receive (x) an amount of cash equal to the Closing Amount multiplied by the number of shares of Common Stock subject to such RSU immediately prior to the Effective Time, net of all applicable withholding taxes, and (y) a number of CVRs equal to the under of the shares of Common Stock underlying the RSU.  There is no vesting applicable to the cash payment and the CVRs.

(6) This option provided for vesting in 12 substantially equal monthly installments from May 20, 2025.

(7) This option provided for vesting in 36 substantially equal monthly installments from November 12, 2024.

(8) Represents shares of Common Stock held directly by ARCH Venture Fund XIII, L.P.("ARCH Venture Fund XIII"). ARCH Venture Partners XIII, L.P. ("AVP XIII LP"), as the sole general partner of ARCH Venture Fund XIII, may be deemed to beneficially own the shares held by ARCH Venture Fund XIII. ARCH Venture Partners XIII, LLC ("AVP XIII LLC"), as the sole general partner of AVP XIII LP, may be deemed to beneficially own the shares held by ARCH Venture Fund XIII. AVP XIII LP and AVP XIII LLC disclaim beneficial ownership except to the extent of any pecuniary interest therein. As members of the investment committee of AVP XIII LLC, each of Paul L. Berns, Kristina M. Burow, Keith Crandell, Steven Gillis and Robert Nelsen (the "AVP XIII Committee Members") may also be deemed to share the power to direct the disposition and vote of the ARCH Venture Fund XIII shares. Each AVP XIII Committee Member disclaims beneficial ownership except to the extent of any pecuniary interest therein.

**Signature:** /s/ Matthew Lang, Attorney-in-Fact for Paul L. Berns  
**Date:** 2025-11-13

### Remarks:

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).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

**Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.**