Monte Rosa Therapeutics Terminates ATM Prospectus After Selling 2.96M Shares For $24.2M In Net Proceeds

Effective January 7, 2026, Monte Rosa Therapeutics, Inc. (the "Company") terminated the sales agreement prospectus (the "ATM Prospectus") filed with the Company's registration statement on Form S-3 (File No. 333-285942) (the "Registration Statement") and related to the shares of the Company's common stock, par value $0.0001 per share ("Common Stock"), issuable pursuant to the Open Market Sale Agreement, dated July 1, 2022, by and among the Company and Jefferies LLC, as amended by Amendment No. 1 to the Open Market Sale Agreement, dated March 20, 2025, by and among the Company and Jefferies LLC (collectively, the "Sales Agreement"). As a result, the Company will not make any sales of Common Stock pursuant to the Sales Agreement, unless and until a new prospectus, prospectus supplement or a new registration statement is filed. Other than the termination of the ATM Prospectus, the Sales Agreement remains in full force and effect. As of January 7, 2026, the Company has issued and sold 2,955,082 of shares of Common Stock under the Sales Agreement, for aggregate net proceeds of $24.2 million.