SCHEDULE 13D/A 0001214659-25-009148 0001232621 XXXXXXXX LIVE 2 Common Stock, par value $0.001 per share 08/29/2025 false 0001808865 46565G104 ITeos Therapeutics, Inc.

321 Arsenal Street Bldg 312, Floor 3, Suite 301 Watertown MA 02472

Kevin Tang 858-200-3830 4747 Executive Drive Suite 210 San Diego CA 92121 0001232621 N TANG CAPITAL MANAGEMENT, LLC WC N DE 0.00 10000.00 0.00 10000.00 10000.00 N 100 OO 0001178579 N KEVIN TANG WC N X1 0.00 10000.00 0.00 10000.00 10000.00 N 100 IN 0001191935 N TANG CAPITAL PARTNERS, LP WC N DE 0.00 10000.00 0.00 10000.00 10000.00 N 100 PN 0002064011 N TANG CAPITAL PARTNERS INTERNATIONAL, LP WC N DE 0.00 0.00 0.00 0.00 0.00 N 0 PN 0002036763 N TANG CAPITAL PARTNERS III, INC WC N NV 0.00 0.00 0.00 0.00 0.00 N 0 CO 0002036770 N TANG CAPITAL PARTNERS IV, INC WC N NV 0.00 0.00 0.00 0.00 0.00 N 0 CO 0001970065 N CONCENTRA BIOSCIENCES, LLC AF N DE 0.00 10000.00 0.00 10000.00 10000.00 N 100 OO Y CONCENTRA MERGER SUB VIII, INC AF N DE 0.00 0.00 0.00 0.00 0.00 N 0 CO Common Stock, par value $0.001 per share ITeos Therapeutics, Inc. 321 Arsenal Street Bldg 312, Floor 3, Suite 301 Watertown MA 02472 This Schedule 13D/A (this "Statement") amends the Schedule 13D (the "Original Schedule 13D") filed on June 12, 2025, as amended on July 22, 2025. Items 4, 5 and 7 of the Statement are hereby amended and supplemented to the extent hereinafter expressly set forth. Except as amended hereby, the original disclosure set forth in the Statement shall remain unchanged. All capitalized terms used and not expressly defined herein have the respective meanings ascribed to such terms in the Original Schedule 13D. Item 4 of the Schedule 13D is amended by adding the following: Closing of the Merger: As previously disclosed, each of Concentra, the Issuer and Merger Sub entered into the Merger Agreement, which provides for an Offer by Merger Sub for all of the Issuer's Common Stock. The Offer commenced on August 1, 2025. On August 29, 2025, the Offer expired and Merger Sub accepted for purchase a total of 32,226,407 shares tendered and not withdrawn, representing approximately 72.17% of the total shares of the Issuer issued and outstanding. Following the expiration of the Offer, Merger Sub merged with and into the Issuer on August 29, 2025, pursuant to Section 251(h) of the Delaware General Corporation Law, and, among other things, each share of common stock of Merger Sub issued and outstanding immediately before the Effective Time automatically converted into the right to receive the Offer Price, with the Issuer surviving as a wholly owned subsidiary of Concentra. The information previously provided in response to Item 5 is hereby amended and restated by replacing the text thereof in its entirety with the following: The information set forth in the cover pages of this Schedule 13D is hereby incorporated by reference into this Item 5. As of the date hereof the Reporting Persons beneficially own an aggregate of 10,000 shares of the Issuer's Common Stock, representing 100% of the outstanding shares. See item 5(a) above. Except as described in this Amendment No. 2, there have been no transactions in the Issuer's Common Stock during the past 60 days by the Reporting Persons. No person other than a Reporting Person has the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, Common Stock beneficially owned by the Reporting Persons. Not applicable. Exhibit 1: Joint Filing Agreement by and among the Reporting Persons (filed as Exhibit 1 of the 13D filed on June 12, 2025 by the Reporting Persons with respect to the Common Stock of the Issuer). Exhibit 2: Schedule A: Transactions during the past 60 days (filed as Exhibit 2 of the 13D filed on June 12, 2025 by the Reporting Persons with respect to the Common Stock of the Issuer). Exhibit 3: Agreement and Plan of Merger, dated as of July 18, 2025, by and among iTeos Therapeutics, Inc., Concentra Biosciences, LLC, and Concentra Merger Sub VIII, Inc. (filed as Exhibit 2.1 of the Issuer's Current Report filed on Form 8-K on July 21, 2025). Exhibit 4: Schedule TO (filed by Concentra on August 1, 2025). Exhibit 5: Offer to Purchase, dated August 1, 2025 (filed as Exhibit (a)(1)(A) to the Schedule TO filed by Concentra on August 1, 2025). Exhibit 6: Form of Letter of Transmittal (filed as Exhibit (a)(1)(B) to the Schedule TO filed by Concentra on August 1, 2025). Exhibit 7: Form of Letter to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees (filed as Exhibit (a)(1)(C) to the Schedule TO filed by Concentra on August 1, 2025). Exhibit 8: Form of Letter to Clients for Use by Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees (filed as Exhibit (a)(1)(D) to the Schedule TO filed by Concentra on August 1, 2025). Exhibit 9: Confidentiality Agreement, dated June 10, 2025, between iTeos and TCM (filed as Exhibit (d)(2) to the Schedule TO filed by Concentra on August 1, 2025). Exhibit 10: Limited Guaranty, dated July 18, 2025 (filed as Exhibit (d)(3) to the Schedule TO filed by Concentra on August 1, 2025). Exhibit 11: Joint Filing Agreement, dated September 3, 2025, by and among the Reporting Persons. TANG CAPITAL MANAGEMENT, LLC /s/ Kevin Tang 09/03/2025 KEVIN TANG /s/ Kevin Tang 09/03/2025 TANG CAPITAL PARTNERS, LP /s/ Kevin Tang 09/03/2025 TANG CAPITAL PARTNERS INTERNATIONAL, LP /s/ Kevin Tang 09/03/2025 TANG CAPITAL PARTNERS III, INC /s/ Kevin Tang 09/03/2025 TANG CAPITAL PARTNERS IV, INC /s/ Kevin Tang 09/03/2025 CONCENTRA BIOSCIENCES, LLC /s/ Kevin Tang 09/03/2025 CONCENTRA MERGER SUB VIII, INC /s/ Kevin Tang 09/03/2025