# EDGAR Filing Document

**Accession Number:** 0001802528
**File Stem:** 0001104659-25-102608
**Filing Date:** 2025-10
**Character Count:** 13860
**Document Hash:** 85060bf251d9542869f39e7de07c9ff2
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-25-102608.hdr.sgml**: 20251027

**ACCESSION NUMBER**: 0001104659-25-102608

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

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20251027

**DATE AS OF CHANGE**: 20251027

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Viridian Therapeutics, Inc.\DE
- **CENTRAL INDEX KEY:** 0001590750
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 471187261
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-88625
- **FILM NUMBER:** 251420282

**BUSINESS ADDRESS:**
- **STREET 1:** 221 CRESCENT STREET
- **STREET 2:** SUITE 103A
- **CITY:** WALTHAM
- **STATE:** MA
- **ZIP:** 02453
- **BUSINESS PHONE:** 617.272.4600

**MAIL ADDRESS:**
- **STREET 1:** 221 CRESCENT STREET
- **STREET 2:** SUITE 103A
- **CITY:** WALTHAM
- **STATE:** MA
- **ZIP:** 02453

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** MIRAGEN THERAPEUTICS, INC.
- **DATE OF NAME CHANGE:** 20170213

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** MIRAGEN THERAPEUTICS, INC.
- **DATE OF NAME CHANGE:** 20170213

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** SIGNAL GENETICS, INC.
- **DATE OF NAME CHANGE:** 20140710
**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, $0.01 par value per share, of Viridian Therapeutics, 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 27, 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 GP LLC** | **FAIRMOUNT HEALTHCARE FUND II GP LLC** | **FAIRMOUNT HEALTHCARE FUND II GP LLC** |
| By: | /s/ Peter Harwin | /s/ Tomas Kiselak |
|  | Peter Harwin | Tomas Kiselak |
|  | Managing Member | Managing Member |

---

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

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**(Amendment No. 7)**

**Viridian Therapeutics, Inc.\DE**

*(Name of Issuer)*

**Common Stock, $0.01 par value**

*(Title of Class of Securities)*

**92790C104**

*(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)*

**10/23/2025**

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

| **CUSIP No.** | **92790C104** |

---

| | | | |
|:--|:--|:--|:--|
| 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>**16025330.00** |
| 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>**16025330.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**16025330.00** | Aggregate amount beneficially owned by each reporting person<br>**16025330.00** | |
| 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>**15.14%** | Percent of class represented by amount in Row (11)<br>**15.14%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IA** | Type of Reporting Person (See Instructions)<br>**IA** | |

---

**Comment for Reporting Person:** The securities include (i) 3,914,458 shares of common stock, $0.01 par value per share (the "Common Stock") and (ii) an aggregate of 12,110,872 shares of Common Stock issuable upon conversion of 133,191 shares of Series A Non-Voting Convertible Preferred Stock, par value $0.01 per share (the "Series A Preferred Stock") and 48,463 shares of Series B Non-Voting Convertible Preferred Stock, par value $0.01 per share (the "Series B Preferred Stock"), the conversion of each of which is subject to a beneficial ownership limitation of 19.99% of the outstanding Common Stock.

Row 13 is based on 105,830,130 shares of Common Stock outstanding as of October 23, 2025, consisting of (i) 93,719,258 shares of Common Stock outstanding as of October 21, 2025, as reported in the Company's final prospectus supplement filed pursuant to Rule 424(b)(5) dated October 21, 2025 (ii) an aggregate of 12,110,872 shares of Common Stock issuable upon conversion of 133,191 shares of Series A Preferred Stock and 48,463 shares of Series B Preferred Stock.

| **CUSIP No.** | **92790C104** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Fairmount Healthcare Fund II GP LLC** | Name of reporting person<br>**Fairmount Healthcare Fund II GP 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>**16025330.00** |
| 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>**16025330.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**16025330.00** | Aggregate amount beneficially owned by each reporting person<br>**16025330.00** | |
| 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>**15.14%** | Percent of class represented by amount in Row (11)<br>**15.14%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

**Comment for Reporting Person:** The securities include (i) 3,914,458 shares of Common Stock and (ii) an aggregate of 12,110,872 shares of Common Stock issuable upon conversion of 133,191 shares of Series A Preferred Stock and 48,463 shares of Series B Preferred Stock, the conversion of each of which is subject to a beneficial ownership limitation of 19.99% of the outstanding Common Stock.

Row 13 is based on 105,830,130 shares of Common Stock outstanding as of October 23, 2025, consisting of (i) 93,719,258 shares of Common Stock outstanding as of October 21, 2025, as reported in the Company's final prospectus supplement filed pursuant to Rule 424(b)(5) dated October 21, 2025 (ii) an aggregate of 12,110,872 shares of Common Stock issuable upon conversion of 133,191 shares of Series A Preferred Stock and 48,463 shares of Series B Preferred Stock.

**Item 1. Security and Issuer**

**(a) Title of Class of Securities:**
Common Stock, $0.01 par value

**(b) Name of Issuer:**
Viridian Therapeutics, Inc.\DE

**(c) Address of Issuer's Principal Executive Offices:**
221 Crescent Street, Suite 103A, Waltham, MA, 02453

This Amendment No. 7 amends and supplements the statement on Schedule 13D originally filed with the Securities and Exchange Commission on January 5, 2021, Amendment No. 1 filed on September 23, 2021, Amendment No. 2 filed on August 19, 2022, Amendment No. 3 filed on November 3, 2023, Amendment No. 4 filed on January 24, 2024, Amendment No. 5 filed on April 1, 2024, and Amendment No. 6 filed on September 17, 2024 (as amended, the "Statement" or the "Schedule 13D") by the Reporting Persons with respect to the common stock, $0.01 par value ("Common Stock"), of Viridian Therapeutics, Inc. (the "Company"). Unless otherwise defined herein, capitalized terms used in this Amendment No. 7 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 is hereby amended and supplemented as follows:

Fund II purchased the shares of Common Stock referenced in Item 3 for investment purposes.

**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. 7 is incorporated by reference herein.

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

**(c)**
On October 23, 2025, Fund II purchased in the Offering a total of 454,545 shares of Common Stock of the Company at a purchase price of $22 per share for an aggregate purchase price of $9,999,990.00.

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

Lock-Up Agreement

In connection with the Company's underwritten public offering of common stock that closed on October 23, 2025, the Fund II entered into a customary lock-up letter agreement (the "Lock-Up Agreement") with Jefferies LLC, Leerink Partners LLC, Evercore Group L.L.C. and Stifel, Nicolaus & Company Incorporated as the representatives of the underwriters (the "Representatives") to an underwriting agreement with the Company. Pursuant to the Lock-Up Agreement, Fund II agreed to refrain from selling shares of the Company's securities without the consent of Jefferies LLC and Leerink Partners LLC, and other customary lock-up conditions, for a period of 60 days from the date of the Company's final prospectus supplement related to the offering.

The foregoing description of the Lock-Up Agreement does not purport to be complete and is qualified in its entirety by reference to the form of the Lock-Up Agreement, which is filed as Exhibit 99.2 to this Schedule 13D and 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:** 10/27/2025

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 GP LLC

**Signature:** /s/ Peter Harwin

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

**Date:** 10/27/2025