Amendment: SEC Form SCHEDULE 13D/A filed by Scholar Rock Holding Corporation

The address of the principal business office of each of the Reporting Persons is 628 Middlefield Road, Palo Alto, CA 94301.

The principal business of the Reporting Persons is venture capital investments. Dr. Akkaraju serves as the Managing Member of each of Samsara GP, which is the general partner of Samsara LP, and Samsara Opportunity GP, which is the general partner of Samsara Opportunity Fund.

During the last five years, none of the Reporting Persons has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors).

During the last five years, none of the Reporting Persons was a party to a civil proceeding of a judicial of administrative body of competent jurisdiction or were subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

Each of Samsara LP, Samsara GP, Samsara Opportunity Fund and Samsara Opportunity GP was organized in the state of Delaware and Dr. Akkaraju is a citizen of the United States.

Item 3 of the Statement is hereby amended and supplemented as follows: On October 3, 2025, Samsara Opportunity Fund purchased 276,578 shares of common stock from Samsara LP in a private sale for $37.44 per share, or an aggregate purchase price of $10,355,080.32. These shares represented shares held by Samsara LP for the exclusive benefit of limited partners who had redeemed their respective interests in Samsara LP and in which neither Samsara GP nor Dr. Akkaraju had any economic interest. These purchases were for cash and were funded by capital contributions from the general and limited partners of Samsara Opportunity Fund. On October 3, 2025, Samsara Opportunity Fund purchased the following shares in open market transactions: - 11,011 shares at prices ranging from $35.14 to $36.13 per share (a weighted-average price of $35.61 per share); - 56,703 shares at prices ranging from $36.14 to $37.1391 per share (a weighted-average price of $36.74 per share); and - 43,122 shares at prices ranging from $37.14 to $37.6227 per share (a weighted-average price of $37.32 per share). On October 6, 2025, Samsara Opportunity Fund purchased the following shares in open market transactions: - 18,414 shares at prices ranging from $37.23 to $38.2276 per share (a weighted-average price of $37.89 per share); - 80,863 shares at prices ranging from $38.23 to $39.2298 per share (a weighted-average price of $38.68 per share); and - 13,748 shares at prices ranging from $39.23 to $39.84 per share (a weighted-average price of $39.52 per share). These open market purchases were for cash and were funded by capital contributions from the general and limited partners of Samsara Opportunity Fund and a short-term working capital loan in the amount of $608,000 from Samsara BioCapital LLC.

Rows 11 and 13 of each Reporting Person's cover page to this Schedule 13D/A set forth the aggregate number of shares of common stock and percentages of the shares of common stock beneficially owned by such Reporting Person and are incorporated by reference. The percentage set forth in each row 13 is based upon the sum of (i) 96,127,265 shares of common stock outstanding as of August 1, 2025, as reported in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025; (ii) 1,064,804 shares of common stock issuable upon the exercise of RD Warrants; and (iii) with respect to Dr. Akkaraju, 110,000 shares of common stock issuable upon the exercise of stock options within 60 days. The Reporting Persons' beneficial ownership of the Issuer's securities consists of (i) 5,302,810 shares of common stock directly held by Samsara LP; (ii) RD Warrants immediately exercisable for up to 1,064,804 shares of common stock directly held by Samsara LP; (iii) 500,439 shares of common stock directly held by Samsara Opportunity Fund; (iv) 13,500 shares of common stock held by Dr. Akkaraju; and (v) 110,000 vested stock options (right to buy) held by Dr. Akkaraju. Samsara GP is the sole general partner of Samsara LP and Dr. Akkaraju is the managing member of Samsara GP. Each of Samsara GP and Dr. Akkaraju possesses power to direct the voting and disposition of the securities held by Samsara LP. Samsara Opportunity GP is the sole general partner of Samsara Opportunity Fund and Dr. Akkaraju is the managing member of Samsara Opportunity GP. Each of Samsara Opportunity GP and Dr. Akkaraju possesses power to direct the voting and disposition of the securities held by Samsara Opportunity Fund.

Rows 7 through 10 of each Reporting Person's cover page to this Schedule 13D/A set forth the number of shares of common stock as to which such Reporting Person has the sole or shared power to vote or direct the vote and sole or shared power to dispose or to direct the disposition and are incorporated by reference.

On October 3, Samsara LP also sold 33,508 shares in an open market transaction. These shares were held by Samsara for the exclusive benefit of limited partners who had redeemed their respective interests in Samsara LP and in which neither Samsara GP nor Dr. Akkaraju had any economic interest. Except as set forth in the preceding sentence and elsewhere herein, none of the Reporting Persons has effected any transactions with respect to the securities of the Issuer during the past sixty days.

No other person is known to have the right to receive or the power to direct the receipt of dividends from, or any proceeds from the sale of, the securities beneficially owned by any of the Reporting Persons.

Not applicable.

Exhibit 99.1 Joint Filing Agreement