Common Stock

CAMP4 THERAPEUTICS CORPORATION

One Kendall Square, Cambridge, MA, 02139

This Schedule 13D/A is filed by 5AM Ventures VI, L.P. ("Ventures VI"), 5AM Partners VI, LLC ("Partners VI"), 5AM Ventures VII, L.P. ("Ventures VII"), 5AM Partners VII, LLC ("Partners VII"), 5AM Opportunities II, L.P. ("Opportunities II"), 5AM Opportunities II (GP), LLC ("Opportunities II GP"), Andrew J. Schwab ("Schwab") and Dr. Kush Parmar ("Parmar"). The foregoing entities and individuals are collectively referred to herein as the "Reporting Persons." The agreement among the Reporting Persons to file this Schedule 13D/A jointly in accordance with Rule 13d-1(k) of the Act is attached hereto as Exhibit 99.1.

The principal business office of the Reporting Persons is 4 Embarcadero Center, Suite 3110, San Francisco, CA 94111.

The principal business of the Reporting Persons is venture capital investments. Each of the individuals serves as a managing member of each of Partners VI, which is the general partner of Ventures VI, Partners VII, which is the general partner of Ventures VII, and Opportunities II GP, which is the general partner of Opportunities II.

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 Ventures VI, Partners VI, Ventures VII, Partners VII, Opportunities II and Opportunities II GP are organized in the state of Delaware and each of the individuals is a citizen of the United States.

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 of the Issuer and percentage of the shares of common stock of the Issuer beneficially owned by such Reporting Person and are incorporated herein by reference. The percentage set forth in each row 13 is based upon 62,753,200 shares of common stock outstanding as of August 12, 2026, as reported in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 13, 2026, and giving effect to Pre-Funded Warrants and stock options, to the extent exercisable within 60 days hereof, as applicable, as referenced herein. Parmar's and Schwab's beneficial ownership percentages are 9.98% and 9.99%, respectively. Due to field limitations of the EDGAR filing system, the percentages listed in Row 13 of each of the cover pages for Parmar and Schwab have been rounded down to 9.9%. The Reporting Persons' ownership of the Issuer's securities consists of (i) 2,033,270 shares of common stock directly held by Ventures VI; (ii) 2,941,176 shares of common stock and Pre-Funded Warrants exercisable for up to 3,179,558 shares of common stock directly held by Ventures VII; (iii) 302,770 shares of common stock directly held by Opportunities II; and (iv) 9,000 vested stock options (right to buy) held by Schwab. The Pre-Funded Warrants contain a provision (the "Beneficial Ownership Blocker"), which precludes the exercise of the Pre-Funded Warrants to the extent that, following exercise, Ventures VII, together with its affiliates and other attribution parties, would own more than 9.99% of the common stock outstanding. Ventures VII is currently prohibited from exercising the Pre-Funded Warrants to the extent that such exercise would result in the Reporting Persons' beneficial ownership of more than 6,379,125 shares of common stock. Partners VI is the sole general partner of Ventures VI, Partners VII is the sole general partner of Ventures VII and Opportunities II GP is the sole general partner of Opportunities II. Schwab and Parmar are managing members of Partners VI, Partners VII and Opportunities II GP and share voting and dispositive power over, and may be deemed to beneficially own, the shares held by Ventures VI, Ventures VII and Opportunities II.

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.

Except as set forth below, none of the Reporting Persons has effected any transactions with respect to the securities of the Issuer since the most recent amendment to the Statement. Weighted Low High Reporting Transaction No. of Average Price Price Transaction Person Date Shares Price ($) ($) ($) Open Market Sale Ventures VI 08/19/2026 45,147 4.76 4.75 5.00 Open Market Sale Ventures VI 08/20/2026 114,700 4.54 4.50 4.91 Open Market Sale Ventures VI 08/21/2026 32,018 4.50 4.50 4.53 Open Market Sale Ventures VI 08/24/2026 10 4.50 4.50 4.50 Block Sale Ventures VI 08/27/2026 400,000 4.04 n/a n/a

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.