# EDGAR Filing Document

**Accession Number:** 0001802528
**File Stem:** 0001104659-25-097923
**Filing Date:** 2025-10
**Character Count:** 27109
**Document Hash:** 0b926bc8a8194c2c63568716321a9086
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-25-097923.hdr.sgml**: 20251008

**ACCESSION NUMBER**: 0001104659-25-097923

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

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20251008

**DATE AS OF CHANGE**: 20251008

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Jade Biosciences, Inc.
- **CENTRAL INDEX KEY:** 0001798749
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 831377888
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-92668
- **FILM NUMBER:** 251382478

**BUSINESS ADDRESS:**
- **STREET 1:** 221 CRESCENT ST.
- **STREET 2:** BUILDING 23, SUITE 105
- **CITY:** WALTHAM
- **STATE:** MA
- **ZIP:** 02453
- **BUSINESS PHONE:** (781) 312-3013

**MAIL ADDRESS:**
- **STREET 1:** 221 CRESCENT ST.
- **STREET 2:** BUILDING 23, SUITE 105
- **CITY:** WALTHAM
- **STATE:** MA
- **ZIP:** 02453

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Aerovate Therapeutics, Inc.
- **DATE OF NAME CHANGE:** 20200103
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Fairmount Funds Management LLC
- **CENTRAL INDEX KEY:** 0001802528

**ORGANIZATION NAME:**
- **EIN:** 364841215
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

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

**BUSINESS ADDRESS:**
- **STREET 1:** 200 BARR HARBOR DRIVE
- **STREET 2:** SUITE 400
- **CITY:** WEST CONSHOHOCKEN
- **STATE:** PA
- **ZIP:** 19428
- **BUSINESS PHONE:** 267-262-5300

**MAIL ADDRESS:**
- **STREET 1:** 200 BARR HARBOR DRIVE
- **STREET 2:** SUITE 400
- **CITY:** WEST CONSHOHOCKEN
- **STATE:** PA
- **ZIP:** 19428

## Exhibit 99.1

**EXHIBIT 99.1**

**JOINT FILING AGREEMENT**

In accordance with Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended, the undersigned agree to the joint filing on behalf of each of them of a Statement on Schedule 13D (including any and all amendments thereto) with respect to the Common Stock, $0.0001 par value per share, of Jade Biosciences, Inc. and further agree that this Joint Filing Agreement shall be included as an exhibit to such joint filing.

The undersigned further agree that each party hereto is responsible for the timely filing of such Statement on Schedule 13D and any amendments thereto, and for the accuracy and completeness of the information concerning such party contained therein; provided, however, that no party is responsible for the accuracy or completeness of the information concerning any other party, unless such party knows or has reason to believe that such information is inaccurate.

This Joint Filing Agreement may be signed in counterparts with the same effect as if the signature on each counterpart were upon the same instrument.

Date: October 8, 2025

---

| | | |
|:---|:---|:---|
| **FAIRMOUNT FUNDS MANAGEMENT LLC** | **FAIRMOUNT FUNDS MANAGEMENT LLC** | **FAIRMOUNT FUNDS MANAGEMENT LLC** |
| By: | /s/ Peter Harwin | /s/ Tomas Kiselak |
|  | Peter Harwin | Tomas Kiselak |
|  | Managing Member | Managing Member |
| **FAIRMOUNT HEALTHCARE FUND II L.P.** | **FAIRMOUNT HEALTHCARE FUND II L.P.** | **FAIRMOUNT HEALTHCARE FUND II L.P.** |
| By: | /s/ Peter Harwin | /s/ Tomas Kiselak |
|  | Peter Harwin | Tomas Kiselak |
|  | Managing Member | Managing Member |

---

---

| | | |
|:---|:---|:---|
| **FAIRMOUNT HEALTHCARE CO-INVEST IV L.P.** | **FAIRMOUNT HEALTHCARE CO-INVEST IV L.P.** | **FAIRMOUNT HEALTHCARE CO-INVEST IV L.P.** |
| By: | /s/ Peter Harwin | /s/ Tomas Kiselak |
|  | Peter Harwin | Tomas Kiselak |
|  | Managing Member | Managing Member |

---

---

| |
|:---|
| /s/ Peter Harwin |
| Peter Harwin |
| /s/ Tomas Kiselak |
| Tomas Kiselak |

---

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

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**(Amendment No. 1)**

**Jade Biosciences, Inc.**

*(Name of Issuer)*

**Common Stock, $0.0001 par value**

*(Title of Class of Securities)*

**008064206**

*(CUSIP Number)*

**Ms. Erin O'Connor**<br>Fairmount Funds Management LLC<br>200 Barr Harbor Drive, Suite 400<br>West Conshohocken PA 19428<br>(267) 262-5300

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

**10/06/2025**

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

| **CUSIP No.** | **008064206** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Fairmount Funds Management LLC** | Name of reporting person<br>**Fairmount Funds Management LLC** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (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>**10353875.00** |
| 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>**10353875.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**10353875.00** | Aggregate amount beneficially owned by each reporting person<br>**10353875.00** | |
| 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>**19.99%** | Percent of class represented by amount in Row (11)<br>**19.99%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IA** | Type of Reporting Person (See Instructions)<br>**IA** | |

---

**Comment for Reporting Person:** The securities (a) include (i) 1,897,677 shares of common stock, $0.0001 par value per share (the "Common Stock"), 46,381 shares of Common Stock issuable upon the exercise of Pre-Funded Warrants and 5,754,000 shares of Common Stock issuable upon conversion of 5,754 shares of Series A non-voting convertible preferred stock, par value $0.0001 per share (the "Series A Preferred Stock"), directly held by Fairmount Healthcare Fund II L.P., a Delaware limited partnership ("Fund II"), and (ii) 2,655,817 shares of Common Stock directly held by Fairmount Healthcare Co-Invest IV L.P., a Delaware limited partnership ("Co-Invest"), and (b) exclude (i) 5,743,825 shares of Common Stock issuable upon exercise of Pre-Funded Warrants and (ii) 6,868,000 shares of Common Stock issuable upon conversion of 6,868 shares of Series A Preferred Stock, in each case directly held by Fund II, as the exercise of the Pre-Funded Warrants is subject to a beneficial ownership limitation of 9.99% of the outstanding Common Stock and the conversion of the Series A Preferred Stock is subject to a beneficial ownership limitation of 19.99%. At such time as Fairmount Funds Management LLC, a Delaware limited liability company and Securities and Exchange Commission registered investment adviser under the Investment Advisers Act of 1940 ("Fairmount"), and its affiliates beneficially own 9.0% or less of the Common Stock, the beneficial ownership limitation with respect to the Series A Preferred Stock will automatically reduce to 9.99%.

Row 13 is based on 51,795,275 shares of Common Stock outstanding as of October 8, 2025, consisting of (i) 32,626,730 shares of Common Stock outstanding as of August 8, 2025, as reported in the Company's most recent Quarterly Report on Form 10-Q, (ii) a total of 13,368,164 shares of Common Stock issued in the Company's private placement on October 6, 2025, as reported in the Company's Current Report on Form 8-K filed on October 7, 2025, (iii) the 46,381 shares of Common Stock underlying the Pre-Funded Warrants, and (iv) the 5,754,000 shares of Common Stock underlying the 5,754 shares of Series A Preferred Stock owned by the Reporting Persons, subject to the respective beneficial ownership limitations.

| **CUSIP No.** | **008064206** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Fairmount Healthcare Fund II L.P.** | Name of reporting person<br>**Fairmount Healthcare Fund II L.P.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (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>**7698058.00** |
| 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>**7698058.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**7698058.00** | Aggregate amount beneficially owned by each reporting person<br>**7698058.00** | |
| 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>**14.86%** | Percent of class represented by amount in Row (11)<br>**14.86%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

**Comment for Reporting Person:** The securities (a) include 1,897,677 shares of Common Stock, 46,381 shares of Common Stock issuable upon the exercise of Pre-Funded Warrants, and 5,754,000 shares of Common Stock issuable upon conversion of 5,754 shares of Series A Preferred Stock held directly by Fund II and (b) exclude 5,743,825 shares of Common Stock issuable upon exercise of Pre-Funded Warrants and 6,868,000 shares of Common Stock issuable upon conversion of 6,868 shares of Series A Preferred Stock, as the exercise of the Pre-Funded Warrants is subject to a beneficial ownership limitation of 9.99% of the outstanding Common Stock and the conversion of the Series A Preferred Stock is subject to a beneficial ownership limitation of 19.99%. At such time as Fairmount and its affiliates beneficially own 9.0% or less of the Common Stock, the beneficial ownership limitation with respect to the Series A Preferred Stock will automatically reduce to 9.99%.

Row 13 is based on 51,795,275 shares of Common Stock outstanding as of October 8, 2025, consisting of (i) 32,626,730 shares of Common Stock outstanding as of August 8, 2025, as reported in the Company's most recent Quarterly Report on Form 10-Q, (ii) a total of 13,368,164 shares of Common Stock issued in the Company's private placement on October 6, 2025, as reported in the Company's Current Report on Form 8-K filed on October 7, 2025, (iii) the 46,381 shares of Common Stock underlying the Pre-Funded Warrants, and (iv) the 5,754,000 shares of Common Stock underlying the 5,754 shares of Series A Preferred Stock owned by Fund II, subject to the respective beneficial ownership limitations.

| **CUSIP No.** | **008064206** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Fairmount Healthcare Co-Invest IV L.P.** | Name of reporting person<br>**Fairmount Healthcare Co-Invest IV L.P.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (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>**2655817.00** |
| 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>**2655817.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**2655817.00** | Aggregate amount beneficially owned by each reporting person<br>**2655817.00** | |
| 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>**5.77%** | Percent of class represented by amount in Row (11)<br>**5.77%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

**Comment for Reporting Person:** The securities include 2,655,817 shares of Common Stock held directly by Co-Invest.

Row 13 is based on 45,994,894 shares of Common Stock outstanding as of October 8, 2025, consisting of (i) 32,626,730 shares of Common Stock outstanding as of August 8, 2025, as reported in the Company's most recent Quarterly Report on Form 10-Q, and (ii) a total of 13,368,164 shares of Common Stock issued in the Company's private placement on October 6, 2025, as reported in the Company's Current Report on Form 8-K filed on October 7, 2025.

| **CUSIP No.** | **008064206** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Peter Evan Harwin** | Name of reporting person<br>**Peter Evan Harwin** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (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>**X1** | Citizenship or place of organization<br>**X1** | |
| 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>**10353875.00** |
| 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>**10353875.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**10353875.00** | Aggregate amount beneficially owned by each reporting person<br>**10353875.00** | |
| 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>**19.99%** | Percent of class represented by amount in Row (11)<br>**19.99%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

**Comment for Reporting Person:** The information in the "Comments" to the cover page for Fairmount Funds Management LLC above is hereby incorporated by reference.

| **CUSIP No.** | **008064206** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Tomas Kiselak** | Name of reporting person<br>**Tomas Kiselak** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (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>**2B** | Citizenship or place of organization<br>**2B** | |
| 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>**10353875.00** |
| 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>**10353875.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**10353875.00** | Aggregate amount beneficially owned by each reporting person<br>**10353875.00** | |
| 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>**19.99%** | Percent of class represented by amount in Row (11)<br>**19.99%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

**Comment for Reporting Person:** The information in the "Comments" to the cover page for Fairmount Funds Management LLC above is hereby incorporated by reference.

**Item 1. Security and Issuer**

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

**(b) Name of Issuer:**
Jade Biosciences, Inc.

**(c) Address of Issuer's Principal Executive Offices:**
221 Crescent Street, Building 23, Suite 105, Waltham, MA, 02453

This Amendment No. 1 amends and supplements the statement on Schedule 13D originally filed withthe Securities and Exchange Commission (the "SEC") on May 1, 2025 (as amended, the "Statement" or the "Schedule 13D") by the Reporting Persons with respect to the Common Stock of the Company. 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:

Subscription Agreement

On October 6, 2025, the Company entered into a securities purchase agreement (the "Subscription Agreement") for a private investment in public equity ("PIPE") with certain institutional and accredited investors, including Fund II. The PIPE closed on October 8, 2025. Pursuant to the terms of the Subscription Agreement, Fund II purchased a total of 1,333,126 shares of Common Stock at a purchase price of $9.14 per share and Pre-Funded Warrants to purchase 855,047 shares of Common Stock at a purchase price of $9.1399 per Pre-Funded Warrant, which represents the per share purchase price of the shares of Common Stock less the $0.0001 per share exercise price for each Pre-Funded Warrant.

The foregoing description of the Subscription Agreement does not purport to be complete and is qualified in its entirety by reference to the form of the Subscription Agreement, which is filed as Exhibit 99.2 to this Schedule 13D and incorporated herein by reference.

Pre-Funded Warrants

The Pre-Funded Warrants purchased by Fund II in the PIPE will be exercisable at any time after the date of issuance. A holder of Pre-Funded Warrants may not exercise the warrant if the holder, together with its affiliates, would beneficially own more than 9.99%, as applicable, of the number of shares of Common Stock outstanding immediately after giving effect to such exercise. A holder of Pre-Funded Warrants may increase or decrease this percentage to a percentage not in excess of 19.99% by providing at least 61 days' prior notice to the Company.

The foregoing description of the Pre-Funded Warrants does not purport to be complete and is qualified in its entirety by reference to the form of Pre-Funded Warrant, which is filed as Exhibit 99.3 to this Schedule 13D and incorporated herein by reference

Registration Rights Agreement

In connection with the PIPE, the Company and investors participating in the PIPE, including Fund II, entered into a registration rights agreement (the "Registration Rights Agreement"), which provides that the Company will register the resale of the shares of Common Stock and the shares of Common Stock underlying the Pre-Funded Warrants sold in the PIPE. Common Shares and Warrant Shares.  The Company is required to prepare and file a registration statement with the Securities and Exchange Commission no later than the earlier of (a) 45 days following the closing of the PIPE and (b) the business day following the date on which the Company files its Quarterly Report on Form 10-Q for the quarter ended September 30, 2025, and to use its reasonable best efforts to have the registration statement declared effective 75 days thereafter, subject to certain exceptions and specified penalties if timely effectiveness is not achieved. The Registration Rights Agreement also provides that the Company is required to pay certain expenses relating to such registrations and indemnify the applicable securityholders against certain liabilities.

The foregoing summary of the Registration Rights Agreement does not purport to be complete and is qualified in its entirety by reference to the form of Registration Rights Agreement, which is filed as Exhibit 99.4 to this Schedule 13D.

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

**(a)**
The information in rows 11 and 13 of each of the cover pages (including the explanatory note in the "Comments") of this Amendment No. 1 is incorporated by reference herein.

**(b)**
The information in rows 7 through 10 of each of the cover pages of this Amendment No. 1 is incorporated by reference herein.

The Reporting Persons' securities (a) include (i) 1,897,677 shares of Common Stock, 46,381 shares of Common Stock issuable upon the exercise of Pre-Funded Warrants and 5,754,000 shares of Common Stock issuable upon conversion of 5,754 shares of Series A Preferred Stock, directly held by Fund II, and (ii) 2,655,817 shares of Common Stock directly held by Co-Invest, and (b) exclude (i) 5,743,825 shares of Common Stock issuable upon exercise of Pre-Funded Warrants and (ii) 6,868,000 shares of Common Stock issuable upon conversion of 6,868 shares of Series A Preferred Stock, in each case directly held by Fund II. The exercise of the Pre-Funded Warrants is subject to a beneficial ownership limitation of 9.99% of the outstanding Common Stock and the conversion of the Series A Preferred Stock is subject to a beneficial ownership limitation of 19.99%. The securities exclude shares of Common Stock issuable upon exercise of Pre-Funded Warrants and conversion of shares of Series A Preferred Stock in excess of such beneficial ownership limitations. At such time as Fairmount and its affiliates beneficially own 9.0% or less of the Common Stock, the beneficial ownership limitation with respect to the Series A Preferred Stock will automatically reduce to 9.99%.

**(c)**
On October 6, 2025, Fund II purchased a total of (i) 1,333,126 shares of Common Stock at a price of $9.14 per share and (ii) Pre-Funded Warrants to purchase 855,047 shares of Common Stock at a purchase price of $9.1399 per Pre-Funded Warrant, which represents the per share purchase price of the shares of Common Stock less the $0.0001 per share exercise price for each Pre-Funded Warrant, in the PIPE for an aggregate purchase price of $19,999,815.72.

**Item 6. Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer.**

The information set forth in Item 4 of this Amendment No. 1 is incorporated herein by reference.

### 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:** Fairmount Funds Management LLC

**Signature:** /s/ Peter Harwin

**Name/Title:** Peter Harwin, Managing Member

**Date:** 10/08/2025

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:** Fairmount Healthcare Fund II L.P.

**Signature:** /s/ Peter Harwin

**Name/Title:** Peter Harwin, Managing Member

**Date:** 10/08/2025

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:** Fairmount Healthcare Co-Invest IV L.P.

**Signature:** /s/ Peter Harwin

**Name/Title:** Peter Harwin, Managing Member

**Date:** 10/08/2025

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:** Peter Evan Harwin

**Signature:** /s/ Peter Harwin

**Name/Title:** Peter Harwin

**Date:** 10/08/2025

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:** Tomas Kiselak

**Signature:** /s/ Tomas Kiselak

**Name/Title:** Tomas Kiselak

**Date:** 10/08/2025