# EDGAR Filing Document

**Accession Number:** 0001812049
**File Stem:** 0001415889-25-021288
**Filing Date:** 2025-8
**Character Count:** 20761
**Document Hash:** fdaace6c4f5e488c555fe65c78236a1d
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001415889-25-021288.hdr.sgml**: 20250807

**ACCESSION NUMBER**: 0001415889-25-021288

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13D/A

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20250807

**DATE AS OF CHANGE**: 20250807

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Vigil Neuroscience, Inc.
- **CENTRAL INDEX KEY:** 0001827087
- **STANDARD INDUSTRIAL CLASSIFICATION:** BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-93233
- **FILM NUMBER:** 251195292

**BUSINESS ADDRESS:**
- **STREET 1:** 100 FORGE ROAD
- **STREET 2:** SUITE 700
- **CITY:** WATERTOWN
- **STATE:** MA
- **ZIP:** 02472
- **BUSINESS PHONE:** 857-254-4445

**MAIL ADDRESS:**
- **STREET 1:** 100 FORGE ROAD
- **STREET 2:** SUITE 700
- **CITY:** WATERTOWN
- **STATE:** MA
- **ZIP:** 02472
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Atlas Venture Fund XII, L.P.
- **CENTRAL INDEX KEY:** 0001812049

**ORGANIZATION NAME:**
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A

**BUSINESS ADDRESS:**
- **STREET 1:** 400 TECHNOLOGY SQUARE
- **STREET 2:** 10TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139
- **BUSINESS PHONE:** 857-201-2700

**MAIL ADDRESS:**
- **STREET 1:** 400 TECHNOLOGY SQUARE
- **STREET 2:** 10TH FLOOR
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02139

## Exhibit 99.1

**Exhibit 99.1**

JOINT FILING AGREEMENT

Pursuant to Rule 13d-1(k)(1) promulgated pursuant to the Securities Exchange Act of 1934, as amended, the undersigned agree that the attached Schedule 13D is being filed on behalf of each of the undersigned.

Date: August 7, 2025

---

| | |
|:---|:---|
| **Atlas Venture Fund XII, L.P.** | **Atlas Venture Fund XII, L.P.** |
| By:  | Atlas Venture Associates XII, L.P., its general partner |
| By: | Atlas Venture Associates XII, LLC, its general partner |
| By: <u>/s/ Ommer Chohan</u> | By: <u>/s/ Ommer Chohan</u> |
| Name:  | Ommer Chohan |
| Title: | Chief Financial Officer |
| **Atlas Venture Associates XII, L.P.** | **Atlas Venture Associates XII, L.P.** |
| By: | Atlas Venture Associates XII, LLC, its general partner |
| By: <u>/s/ Ommer Chohan</u> | By: <u>/s/ Ommer Chohan</u> |
| Name:  | Ommer Chohan |
| Title: | Chief Financial Officer |
| **Atlas Venture Associates XII, LLC** | **Atlas Venture Associates XII, LLC** |
| By: <u>/s/ Ommer Chohan</u> | By: <u>/s/ Ommer Chohan</u> |
| Name:  | Ommer Chohan |
| Title: | Chief Financial Officer |
| **Atlas Venture Opportunity Fund I, L.P.** | **Atlas Venture Opportunity Fund I, L.P.** |
| By:  | Atlas Venture Associates Opportunity I, L.P., its general partner |
| By: | Atlas Venture Associates Opportunity I, LLC, its general partner |
| By: <u>/s/ Ommer Chohan</u> | By: <u>/s/ Ommer Chohan</u> |
| Name:  | Ommer Chohan |
| Title: | Chief Financial Officer |
| **Atlas Venture Associates Opportunity I, L.P.** | **Atlas Venture Associates Opportunity I, L.P.** |
| By: | Atlas Venture Associates Opportunity I, LLC, its general partner |
| By: <u>/s/ Ommer Chohan</u> | By: <u>/s/ Ommer Chohan</u> |
| Name:  | Ommer Chohan |
| Title: | Chief Financial Officer |
| **Atlas Venture Associates Opportunity I, LLC** | **Atlas Venture Associates Opportunity I, LLC** |
| By: <u>/s/ Ommer Chohan</u> | By: <u>/s/ Ommer Chohan</u> |
| Name:  | Ommer Chohan |
| Title: | Chief Financial Officer |

---

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

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**(Amendment No. 1)**

**VIGIL NEUROSCIENCE, INC.**

*(Name of Issuer)*

**Common Stock, $0.0001 par value per share**

*(Title of Class of Securities)*

**92673K108**

*(CUSIP Number)*

**Ommer Chohan, CFO**<br>300 Technology Square, 8th Floor<br>Cambridge MA 02139<br>(857) 201-2700

*(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)*

**08/05/2025**

*(Date of Event Which Requires Filing of this Statement)*

| **CUSIP No.** | **92673K108** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Atlas Venture Fund XII, L.P.** | Name of reporting person<br>**Atlas Venture Fund XII, L.P.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**0.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**0.00** | Aggregate amount beneficially owned by each reporting person<br>**0.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**0.0%** | Percent of class represented by amount in Row (11)<br>**0.0%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

| **CUSIP No.** | **92673K108** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Atlas Venture Associates XII, L.P.** | Name of reporting person<br>**Atlas Venture Associates XII, L.P.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**AF** | Source of funds (See Instructions)<br>**AF** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**0.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**0.00** | Aggregate amount beneficially owned by each reporting person<br>**0.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**0.0%** | Percent of class represented by amount in Row (11)<br>**0.0%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

| **CUSIP No.** | **92673K108** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Atlas Venture Associates XII, LLC** | Name of reporting person<br>**Atlas Venture Associates XII, LLC** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**AF** | Source of funds (See Instructions)<br>**AF** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**0.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**0.00** | Aggregate amount beneficially owned by each reporting person<br>**0.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**0.0%** | Percent of class represented by amount in Row (11)<br>**0.0%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**OO** | Type of Reporting Person (See Instructions)<br>**OO** | |

---

| **CUSIP No.** | **92673K108** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Atlas Venture Opportunity Fund I, L.P.** | Name of reporting person<br>**Atlas Venture Opportunity Fund I, L.P.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**0.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**0.00** | Aggregate amount beneficially owned by each reporting person<br>**0.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**0.0%** | Percent of class represented by amount in Row (11)<br>**0.0%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

| **CUSIP No.** | **92673K108** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Atlas Venture Associates Opportunity I, L.P.** | Name of reporting person<br>**Atlas Venture Associates Opportunity I, L.P.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**AF** | Source of funds (See Instructions)<br>**AF** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**0.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**0.00** | Aggregate amount beneficially owned by each reporting person<br>**0.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**0.0%** | Percent of class represented by amount in Row (11)<br>**0.0%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

| **CUSIP No.** | **92673K108** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Atlas Venture Associates Opportunity I, LLC** | Name of reporting person<br>**Atlas Venture Associates Opportunity I, LLC** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**AF** | Source of funds (See Instructions)<br>**AF** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**0.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**0.00** | Aggregate amount beneficially owned by each reporting person<br>**0.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**0.0%** | Percent of class represented by amount in Row (11)<br>**0.0%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**OO** | Type of Reporting Person (See Instructions)<br>**OO** | |

---

**Item 1. Security and Issuer**

**(a) Title of Class of Securities:**
Common Stock, $0.0001 par value per share

**(b) Name of Issuer:**
VIGIL NEUROSCIENCE, INC.

**(c) Address of Issuer's Principal Executive Offices:**
100 Forge Road, Suite 700, Watertown, MA, 02472

Item 1 of the Statement is amended and supplemented as follows:

This Amendment No. 1 (this "Amendment No. 1" or this "Schedule 13D/A") amends and supplements the statement on Schedule 13D originally filed with the Securities and Exchange Commission (the "SEC") on January 21, 2022 (as amended, the "Statement") by the Reporting Persons. Unless otherwise defined herein, capitalized terms used in this Amendment No. 1 shall have the meanings ascribed to them in the Statement. Unless amended or supplemented below, the information in the Statement remains unchanged.

**Item 4. Purpose of Transaction**

Item 4 of the Statement is hereby amended and supplemented as follows:

On May 21, 2025, the Issuer entered into an Agreement and Plan of Merger (the "Merger Agreement") with Sanofi, a French societe anonyme ("Parent" or "Sanofi"), and Vesper Acquisition Sub Inc., a Delaware corporation and a wholly-owned subsidiary of Parent ("Merger Sub"), pursuant to which, Merger Sub would merge with and into the Issuer (the "Merger"), with the Issuer surviving the merger as a wholly-owned subsidiary of Parent.

On August 4, 2025, at a special meeting of stockholders of the Issuer, the Issuer's stockholders voted to adopt the Merger Agreement.

On August 5, 2025, the Merger closed and each share of the Issuer's Common Stock issued and outstanding, including all of the shares of Common Stock owned by the Reporting Persons, was converted into the right to receive (i) $8.00 per share of Common Stock in cash, without interest plus (ii) one contingent value right, representing the right to receive $2.00 payable in cash, conditioned upon satisfaction of a certain clinical milestone.

**Item 5. Interest in Securities of the Issuer**

**(a)**
As of the date hereof, the Reporting Persons no longer beneficially owns any securities of the Issuer or any percentage of the Issuer's outstanding Common Stock.

**(b)**
As of the date hereof, the Reporting Persons no longer beneficially owns any securities of the Issuer.

**(c)**
Except as descried herein, none of the Reporting Persons have purchased or sold any shares of Common Stock during the past 60 days.

### 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.

**Reporting Person:** Atlas Venture Fund XII, L.P.

**Signature:** /s/ Ommer Chohan

**Name/Title:** By: Atlas Venture Associates XII, L.P., its general partner, By: Atlas Venture Associates XII, LLC, its general partner, By: Ommer Chohan, its CFO

**Date:** 08/07/2025

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.

**Reporting Person:** Atlas Venture Associates XII, L.P.

**Signature:** /s/ Ommer Chohan

**Name/Title:** By: Atlas Venture Associates XII, LLC, its general partner, By: Ommer Chohan, its CFO

**Date:** 08/07/2025

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.

**Reporting Person:** Atlas Venture Associates XII, LLC

**Signature:** /s/ Ommer Chohan

**Name/Title:** Ommer Chohan, CFO

**Date:** 08/07/2025

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.

**Reporting Person:** Atlas Venture Opportunity Fund I, L.P.

**Signature:** /s/ Ommer Chohan

**Name/Title:** By: Atlas Venture Associates Opportunity I L.P., its GP, By: Atlas Venture Associates Opportunity I LLC, its GP, By: Ommer Chohan, its CFO

**Date:** 08/07/2025

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.

**Reporting Person:** Atlas Venture Associates Opportunity I, L.P.

**Signature:** /s/ Ommer Chohan

**Name/Title:** By: Atlas Venture Associates Opportunity I LLC, its GP, By: Ommer Chohan, its CFO

**Date:** 08/07/2025

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.

**Reporting Person:** Atlas Venture Associates Opportunity I, LLC

**Signature:** /s/ Ommer Chohan

**Name/Title:** Ommer Chohan, CFO

**Date:** 08/07/2025