X0202 SCHEDULE 13D/A 0001193125-23-180612 0001802528 XXXXXXXX LIVE 7 Common Stock, $0.0001 par value 06/23/2026 false 0001636282 00773J202 SPYRE THERAPEUTICS, INC.

221 Crescent Street Building 23, Suite 105 Waltham MA 02453

Ms. Erin O'Connor (267) 262-5300 Fairmount Funds Management LLC 200 Barr Harbor Drive, Suite 400 West Conshohocken PA 19428 0001802528 N Fairmount Funds Management LLC a AF N DE 0.00 8835440.00 0.00 8835440.00 8835440.00 N 9.15 IA The securities represent 8,835,440 shares of common stock, $0.0001 par value per share (the "Common Stock") issuable upon conversion of 220,886 shares of Series A Preferred Stock, par value $0.0001 per share (the "Series A Preferred Stock"), held directly by Fairmount Healthcare Fund II L.P. ("Fund II"). The securities exclude shares of Common Stock issuable upon conversion of shares of Series A Preferred Stock held directly by Fund II in excess of the beneficial ownership limitation of 9.99%. Row 13 is based on 96,572,019 shares of Common Stock outstanding as of June 23, 2026, consisting of (i) 86,841,253 shares of Common Stock outstanding as of April 28, 2026, as reported in the Company's Form 10-Q filed on May 5, 2026, (ii) 666,680 shares of Common Stock issued upon the June 23, 2026 conversion by Fund II of 16,667 shares of the Series B Preferred Stock, par value $0.0001 per share (the "Series B Preferred Stock") (iii) 228,646 shares underlying options that are currently exercisable or will be exercisable within 60 days of the date of this filing by the Reporting Persons and (iv) 8,835,440 shares of Common Stock underlying the 220,886 shares of Series A Preferred Stock owned by Fund II, applying the beneficial ownership limitation. 0001769651 N Fairmount Healthcare Fund II L.P. a AF N DE 0.00 8835440.00 0.00 8835440.00 8835440.00 N 9.15 PN The securities represent 8,835,440 shares of Common Stock issuable upon conversion of 220,886 shares of Series A Preferred Stock held directly by Fund II. The securities exclude shares of Common Stock issuable upon conversion of shares of Series A Preferred Stock held directly by Fund II in excess of the beneficial ownership limitation of 9.99%. Row 13 is based on 96,572,019 shares of Common Stock outstanding as of June 23, 2026, consisting of (i) 86,841,253 shares of Common Stock outstanding as of April 28, 2026, as reported in the Company's Form 10-Q filed on May 5, 2026, (ii) 666,680 shares of Common Stock issued upon the June 23, 2026 conversion by Fund II of 16,667 shares of the Series B Preferred Stock (iii) 228,646 shares underlying options that are currently exercisable or will be exercisable within 60 days of the date of this filing by the Reporting Persons and (iv) 8,835,440 shares of Common Stock underlying the 220,886 shares of Series A Preferred Stock owned by Fund II, applying the beneficial ownership limitation. 0001663607 N Peter Evan Harwin a AF N X1 520361.00 9146840.00 520361.00 9146840.00 9667201.00 N 9.99 IN The securities include (a) 406,038 shares of Common Stock held directly by Mr. Harwin, (b) 114,323 shares of Common Stock issuable upon the exercise of options that are currently exercisable or will be exercisable within 60 days of the date of this filing held directly by Mr. Harwin*, and (c) Fund II's direct holdings of 9,146,840 shares of Common Stock issuable upon conversion of 228,671 shares of Series A Preferred Stock held directly by Fund II. The securities exclude shares of Common Stock issuable upon conversion of shares of Series A Preferred Stock held directly by Fund II in excess of the beneficial ownership limitation of 9.99%. Row 13 is based on 96,769,096 shares of Common Stock outstanding as of June 23, 2026, consisting of (i) 86,841,253 shares of Common Stock outstanding as of April 28, 2026, as reported in the Company's Form 10-Q filed on May 5, 2026, (ii) 666,680 shares of Common Stock issued upon the June 23, 2026 conversion by Fund II of 16,667 shares of the Series B Preferred Stock, (iii) 114,323 shares of Common Stock underlying options that are currently exercisable or will be exercisable within 60 days of the date of this filing by Mr. Harwin and (iii) 9,146,840 shares of Common Stock underlying the 228,671 shares of Series A Preferred Stock owned by Fund II, applying the beneficial ownership limitation. * Under Mr. Harwin's arrangement with Fairmount, Mr. Harwin holds the options for one or more investment vehicles managed by Fairmount (each, a "Fairmount Fund"). Mr. Harwin is obligated to turn over to Fairmount any net cash or stock received from the option for the benefit of such Fairmount Fund. Mr. Harwin therefore disclaims beneficial ownership of the option and underlying common stock. 0001830177 N Tomas Kiselak a AF N 2B 520361.00 9146840.00 520361.00 9146840.00 9667201.00 N 9.99 IN The securities include (a) 406,038 shares of Common Stock held directly by Mr. Kiselak, (b) 114,323 shares of Common Stock issuable upon the exercise of options that are currently exercisable or will be exercisable within 60 days of the date of this filing held directly by Mr. Kiselak*, and (c) Fund II's direct holdings of 9,146,840 shares of Common Stock issuable upon conversion of 228,671 shares of Series A Preferred Stock held directly by Fund II. The securities exclude shares of Common Stock issuable upon conversion of shares of Series A Preferred Stock held directly by Fund II in excess of the beneficial ownership limitation of 9.99%. Row 13 is based on 96,769,096 shares of Common Stock outstanding as of June 23, 2026, consisting of (i) 86,841,253 shares of Common Stock outstanding as of April 28, 2026, as reported in the Company's Form 10-Q filed on May 5, 2026, (ii) 666,680 shares of Common Stock issued upon the June 23, 2026 conversion by Fund II of 16,667 shares of the Series B Preferred Stock, (iii) 114,323 shares of Common Stock underlying options that are currently exercisable or will be exercisable within 60 days of the date of this filing by Mr. Harwin and (iii) 9,146,840 shares of Common Stock underlying the 228,671 shares of Series A Preferred Stock owned by Fund II, applying the beneficial ownership limitation. * Under Mr. Kiselak's arrangement with Fairmount, Mr. Kiselak holds the options for one or more investment vehicles managed by Fairmount (each, a "Fairmount Fund"). Mr. Kiselak is obligated to turn over to Fairmount any net cash or stock received from the option for the benefit of such Fairmount Fund. Mr. Kiselak therefore disclaims beneficial ownership of the option and underlying common stock. Common Stock, $0.0001 par value SPYRE THERAPEUTICS, INC. 221 Crescent Street Building 23, Suite 105 Waltham MA 02453 This Amendment No. 7 amends and supplements the statement on Schedule 13D originally filed with the Securities and Exchange Commission (the "SEC") on June 30, 2023, Amendment No. 1 filed on November 29, 2023, Amendment No. 2 filed on December 11, 2023, Amendment No. 3 filed on December 29, 2023, Amendment No. 4 filed on April 25, 2024, Amendment No. 5 filed on October 17, 2025, and Amendment No. 6 filed on April 20, 2026 (as amended, the "Statement" or the "Schedule 13D") by the Reporting Persons with respect to the Common Stock of the Company. Unless otherwise defined herein, capitalized terms used in this Amendment No. 7 shall have the meanings ascribed to them in the Statement. Unless amended or supplemented below, the information in the Statement remains unchanged. Item 3 of the Schedule 13D is hereby amended and supplemented as follows: On June 23, 2026, Fund II delivered to the Company a notice of conversion pursuant to Section 6.2 of the Certificate of Designation of Preferences, Rights and Limitations of Series B Non-Voting Convertible Preferred Stock (the "Certificate of Designation") to convert 16,667 shares of Series B Preferred Stock into 666,680 shares of Common Stock, in accordance with the terms of the Certificate of Designation. The conversion was effected for no cash consideration pursuant to the Certificate of Designation. Item 4 of the Schedule 13D is hereby amended and supplemented as follows: Resignation of Peter Harwin On May 27, 2026, Peter Harwin resigned from the Board of Directors of the Company. Mr. Harwin's resignation was not the result of any disagreement with the Company on any matter relating to the Company's operations, policies or practices. The information in rows 11 and 13 of each of the cover pages (including the explanatory note in the "Comments") of this Amendment No. 7 is incorporated by reference herein. Together, the Reporting Persons' securities include (i) 8,581,440 shares of Common Stock issuable upon conversion of 214,536 shares of Series A Preferred Stock subject to the 9.99% beneficial ownership limitation applied to all of the securities owned by the Reporting Persons and (ii) 228,646 shares of Common Stock issuable upon the exercise of options held by the Reporting Persons that are currently exercisable or will be exercisable within 60 days of the date of this filing. The securities exclude 5,260,360 shares of Common Stock issuable upon conversion of 131,509 shares of Series A Preferred Stock held directly by Fund II in excess of the beneficial ownership limitation of 9.99%. The information in rows 7 through 10 of each of the cover pages of this Amendment No. 7 is incorporated by reference herein. Item 5(c) of the Schedule 13D is hereby supplemented as follows: On June 23, 2026, Fund II sold in a block trade a total of 4,684,781 shares of Common Stock at a price of $85.31 per share. 99.1 Joint Filing Agreement 99.1 (incorporated by reference to Exhibit 99.1 of the Reporting Persons' Schedule 13D filed with the SEC on October 17, 2025). Fairmount Funds Management LLC /s/ Peter Harwin 06/23/2026 /s/ Tomas Kiselak 06/23/2026 Fairmount Healthcare Fund II L.P. /s/ Peter Harwin 06/23/2026 /s/ Tomas Kiselak 06/23/2026 Peter Evan Harwin /s/ Peter Harwin 06/23/2026 Tomas Kiselak /s/ Tomas Kiselak 06/23/2026