SCHEDULE 13G/A 0001104659-25-070820 0001423994 XXXXXXXX LIVE 1 Common stock, par value $0.001 per share 09/30/2025 0001808865 iTeos Therapeutics, Inc. 46565G104 321 Arsenal Street Bldg. 312, Floor 3, Suite 301 Watertown MA 02472 Rule 13d-1(c) Ridgeback Capital Investments L.P. DE 0.00 0.00 0.00 0.00 0.00 N 0.00 OO The percentages used herein are calculated based upon 44,205,398 shares of common stock outstanding as of August 1, 2025, as reported by the Company in its Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025. Ridgeback Capital Investments LLC DE 0.00 0.00 0.00 0.00 0.00 N 0.00 OO The percentages used herein are calculated based upon 44,205,398 shares of common stock outstanding as of August 1, 2025, as reported by the Company in its Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025. Ridgeback Capital Management LLC DE 0.00 0.00 0.00 0.00 0.00 N 0.0 OO The percentages used herein are calculated based upon 44,205,398 shares of common stock outstanding as of August 1, 2025, as reported by the Company in its Quarterly Report on Form 10-Q filed with the SEC on August 6, 2025. iTeos Therapeutics, Inc. 321 Arsenal Street Bldg. 312, Floor 3, Suite 301 Watertown, MA, 02472 This statement is filed on behalf of the following persons with respect to shares of common stock of the Company acquired by them (the "Shares"): (i) Ridgeback Capital Investments L.P., Delaware limited partnership ("RCILP"), with respect to Shares beneficially owned by it; (ii) Ridgeback Capital Investments LLC, a Delaware limited liability company ("RCI"), with respect to Shares beneficially owned by it; and (iii) Ridgeback Capital Management LLC, a Delaware limited liability company ("RCM"), with respect to Shares beneficially owned by it. The foregoing persons are hereinafter referred to collectively as the "Reporting Persons." Any disclosures herein with respect to persons other than the Reporting Persons are made on information and belief after making inquiry to the appropriate party. RCM and RCI do not own any Shares directly. RCI is the general partner of RCILP. Pursuant to an investment management agreement, RCM maintains investment and voting power with respect to the securities held or controlled by RCI. Wayne Holman, an individual, controls RCM. By reason of the provisions of Rule 13d-3 of the Securities Exchange Act of 1934, as amended, RCM and RCI may be deemed to own beneficially all of the Shares (constituting approximately 5.1% of the shares outstanding). Each of RCM and RCI disclaim beneficial ownership of any of the securities covered by this statement, except to the extent of any pecuniary interest therein. 30 Star Island Drive, Miami, FL, 33139 RCILP is a Delaware limited partnership. RCI is a Delaware limited liability company. RCM is a Delaware limited liability company. Y Ridgeback Capital Investments L.P.: -0- Ridgeback Capital Investments LLC: -0- Ridgeback Capital Management LLC: -0- Ridgeback Capital Investments L.P.: 0.0% Ridgeback Capital Investments LLC: 0.0% Ridgeback Capital Management LLC: 0.0% Ridgeback Capital Investments L.P.: -0- Ridgeback Capital Investments LLC: -0- Ridgeback Capital Management LLC: -0- Ridgeback Capital Investments L.P.: -0- Ridgeback Capital Investments LLC: -0- Ridgeback Capital Management LLC: -0- Ridgeback Capital Investments L.P.: -0- Ridgeback Capital Investments LLC: -0- Ridgeback Capital Management LLC: -0- Ridgeback Capital Investments L.P.: -0- Ridgeback Capital Investments LLC: -0- Ridgeback Capital Management LLC: -0- N Y Y Y Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. Exhibit Number 99.1 - Joint Filing Agreement - previously filed Ridgeback Capital Investments L.P. /s/ Nicole Venezia 11/14/2025 Ridgeback Capital Investments LLC /s/ Nicole Venezia 11/14/2025 Ridgeback Capital Management LLC /s/ Nicole Venezia 11/14/2025