# EDGAR Filing Document

**Accession Number:** 0001708269
**File Stem:** 0001708269-25-000004
**Filing Date:** 2025-10
**Character Count:** 23576
**Document Hash:** 67a5b9a577c97fd573bbb004c595ee88
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001708269-25-000004.hdr.sgml**: 20251020

**ACCESSION NUMBER**: 0001708269-25-000004

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

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20251020

**DATE AS OF CHANGE**: 20251020

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Sionna Therapeutics, Inc.
- **CENTRAL INDEX KEY:** 0002036042
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **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:** 005-94871
- **FILM NUMBER:** 251405258

**BUSINESS ADDRESS:**
- **STREET 1:** 21 HICKORY DRIVE, SUITE 500
- **CITY:** WALTHAM
- **STATE:** MA
- **ZIP:** 02451
- **BUSINESS PHONE:** 617-819-2020

**MAIL ADDRESS:**
- **STREET 1:** 21 HICKORY DRIVE, SUITE 500
- **CITY:** WALTHAM
- **STATE:** MA
- **ZIP:** 02451
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Atlas Venture Fund XI, L.P.
- **CENTRAL INDEX KEY:** 0001708269

**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: October 20, 2025

---

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

**SIONNA THERAPEUTICS, INC.**

*(Name of Issuer)*

**Common Stock**

*(Title of Class of Securities)*

**829401108**

*(CUSIP Number)*

**Ommer Chohan, CFO**<br>Atlas Venture<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)*

**10/16/2025**

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

| **CUSIP No.** | **829401108** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Atlas Venture Fund XI, L.P.** | Name of reporting person<br>**Atlas Venture Fund XI, 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>**2382495.00** |
| 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>**2382495.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**2382495.00** | Aggregate amount beneficially owned by each reporting person<br>**2382495.00** | |
| 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>**5.4%** | Percent of class represented by amount in Row (11)<br>**5.4%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

| **CUSIP No.** | **829401108** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Atlas Venture Associates XI, L.P.** | Name of reporting person<br>**Atlas Venture Associates XI, 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>**2382495.00** |
| 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>**2382495.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**2382495.00** | Aggregate amount beneficially owned by each reporting person<br>**2382495.00** | |
| 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>**5.4%** | Percent of class represented by amount in Row (11)<br>**5.4%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

| **CUSIP No.** | **829401108** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Atlas Venture Associates XI, LLC** | Name of reporting person<br>**Atlas Venture Associates XI, 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>**2382495.00** |
| 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>**2382495.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**2382495.00** | Aggregate amount beneficially owned by each reporting person<br>**2382495.00** | |
| 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>**5.4%** | Percent of class represented by amount in Row (11)<br>**5.4%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**OO** | Type of Reporting Person (See Instructions)<br>**OO** | |

---

| **CUSIP No.** | **829401108** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Atlas Venture Opportunity Fund II, L.P.** | Name of reporting person<br>**Atlas Venture Opportunity Fund II, 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>**701985.00** |
| 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>**701985.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**701985.00** | Aggregate amount beneficially owned by each reporting person<br>**701985.00** | |
| 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>**1.6%** | Percent of class represented by amount in Row (11)<br>**1.6%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

| **CUSIP No.** | **829401108** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Atlas Venture Associates Opportunity II, LP** | Name of reporting person<br>**Atlas Venture Associates Opportunity II, LP** | |
| 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>**701985.00** |
| 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>**701985.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**701985.00** | Aggregate amount beneficially owned by each reporting person<br>**701985.00** | |
| 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>**1.6%** | Percent of class represented by amount in Row (11)<br>**1.6%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

| **CUSIP No.** | **829401108** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Atlas Venture Associates Opportunity II, LLC** | Name of reporting person<br>**Atlas Venture Associates Opportunity II, 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>**701985.00** |
| 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>**701985.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**701985.00** | Aggregate amount beneficially owned by each reporting person<br>**701985.00** | |
| 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>**1.6%** | Percent of class represented by amount in Row (11)<br>**1.6%** | |
| 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

**(b) Name of Issuer:**
SIONNA THERAPEUTICS, INC.

**(c) Address of Issuer's Principal Executive Offices:**
21 Hickory Drive, Suite 500, Waltham, MA, 02451

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 February 18, 2025, (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 5. Interest in Securities of the Issuer**

**(a)**
As of the date hereof, Atlas XI is the record owner of 2,382,495 shares of Common Stock. AVA XI LP is the general partner of Atlas XI and AVA XI LLC is the general partner of AVA XI LP. Each of Atlas XI, AVA XI LP and AVA XI LLC has shared voting and dispositive power over the shares held by Atlas XI. As such, each of Atlas XI, AVA XI LP and AVA XI LLC may be deemed to beneficially own the shares held by Atlas XI.

As of the date hereof, AVOF II is the record owner of 701,985 shares of Common Stock. AVAO II LP is the general partner of AVOF II and AVAO II LLC is the general partner of AVAO II LP. Each of AVOF II, AVAO II LP and AVAO II LLC has shared voting and dispositive power over the shares held by AVOF II. As such, each of AVOF II, AVAO II LP and AVAO II LLC may be deemed to beneficially own the shares held by AVOF II.

**(b)**
Each of the Fund XI Reporting Persons and Opportunity Fund II Reporting Persons may be deemed to beneficially own 5.4% and 1.6%, respectively, of the Issuer's outstanding Common Stock, which percentages are calculated based upon 44,139,823 outstanding shares of Common Stock of the Issuer, as reported in the Issuer's Quarterly Report on Form 10-Q, filed with the Securities and Exchange Commission on August 11, 2025.

Collectively, the Reporting Persons beneficially own an aggregate of 3,084,480 shares of Common Stock, which represents 7.0% of the Issuer's outstanding Common Stock. The Fund XI Reporting Persons and the Opportunity Fund II Reporting Persons are under common control and as a result, the Reporting Persons may be deemed to be members of a group. However, the Reporting Persons disclaim such group membership, and this Schedule 13D shall not be deemed an admission that the Reporting Persons are members of a group for purposes of Section 13 or for any other purposes.

**(c)**
(c)	Except as set forth below, none of the Reporting Persons has effected any transactions with respect to the securities of the Issuer in the past sixty days:

Date                 Seller      No. Shares     Price Range	     Weighted Average Price Per Share
9/29/2025	Atlas XI 	54,637	      $29.95 to $30.41	$30.09
9/29/2025	AVOF II	11,468	      $29.95 to $30.41	$30.09
9/30/2025	Fund XI	10,239	      $29.95 to $30.20	$30.06
9/30/2025	AVOF II	2,149	      $29.95 to $30.20	$30.06
10/1/2025	Atlas XI	165	              $29.95	                $29.95
10/1/2025	AVOF II	35	              $29.95	                $29.95
10/3/2025	Atlas XI	31,198	      $29.95 to $30.11	$30.00
10/3/2025	AVOF II	6,548	      $29.95 to $30.11	$30.00
10/6/2025	Atlas XI	9,753	      $29.95 to $30.00	$29.95
10/6/2025	AVOF II	2,047	      $29.95 to $30.00	$29.95
10/10/2025	Atlas XI   16,727	      $29.95 to $30.11	$29.98
10/10/2025	AVOF II	3,511	      $29.95 to $30.11	$29.98
10/13/2025	Atlas XI	44,048	      $29.95 to $30.93	$30.32
10/13/2025	Atlas XI	4,082	      $31.03               	$31.03
10/13/2025	AVOF II	9,245	      $29.95 to $30.93	$30.32
10/13/2025	AVOF II	857	              $31.03               	$31.03
10/14/2025	Atlas XI	501	              $29.95	                $29.95
10/14/2025	AVOF II	105	              $29.95               	$29.95
10/15/2025	Atlas XI	65,726	      $29.95 to $30.94	$30.37
10/15/2025	Atlas XI	30,032	      $30.95 to $31.30	$31.12
10/15/2025	AVOF II	13,795	      $29.95 to $30.94	$30.37
10/15/2025	AVOF II	6,303	      $30.95 to $31.30	$31.12
10/16/2025	Atlas XI	8,596	      $30.14 to $30.74	$30.15
10/16/2025	Atlas XI	45,117	      $31.21 to $32.205	$31.69
10/16/2025	Atlas XI	73,296	      $32.21 to $33.205	$32.84
10/16/2025	Atlas XI	12,888	      $33.21 to $33.86	$33.38
10/16/2025	AVOF II	1,804	      $30.14 to $30.74	$30.15
10/16/2025	AVOF II	9,470	      $31.21 to $32.205	$31.69
10/16/2025	AVOF II	15,384	      $32.21 to $33.205	$32.84
10/16/2025	AVOF II	2,705	      $33.21 to $33.86	$33.38
10/17/2025	Atlas XI	28,821	      $31.325 to $32.32	$32.10
10/17/2025	Atlas XI	21,451	      $32.335 to $33.25	$32.71
10/17/2025	Atlas XI	248	              $33.47 to $33.475	$33.47
10/17/2025	AVOF II	6,049	      $31.325 to $32.32	$32.10
10/17/2025	AVOF II	4,503	      $32.335 to $33.25	$32.71
10/17/2025	AVOF II	52	              $33.47 to $33.475	$33.47
10/20/2025	Atlas XI	20,485	      $31.06 to $32.05	$31.79
10/20/2025	Atlas XI	25,788	      $32.06 to $32.59	$32.33
10/20/2025	AVOF II	4,300	      $31.06 to $32.05	$31.79
10/20/2025	AVOF II	5,412	      $32.06 to $32.59	$32.33

### 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 XI, L.P.

**Signature:** /s/ Ommer Chohan

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

**Date:** 10/20/2025

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 XI, L.P.

**Signature:** /s/ Ommer Chohan

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

**Date:** 10/20/2025

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 XI, LLC

**Signature:** /s/ Ommer Chohan

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

**Date:** 10/20/2025

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 II, L.P.

**Signature:** /s/ Ommer Chohan

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

**Date:** 10/20/2025

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 II, LP

**Signature:** /s/ Ommer Chohan

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

**Date:** 10/20/2025

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 II, LLC

**Signature:** /s/ Ommer Chohan

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

**Date:** 10/20/2025