X0202 SCHEDULE 13G 0001017645 XXXXXXXX LIVE Common Stock, no par value per share 09/08/2026 0001755237 Korsana Biosciences, Inc. 23255M303 203 CRESCENT STREET, BLDGS. #3/3A/4 SUITE 503 WALTHAM MA 02453 Rule 13d-1(d) GENERAL ATLANTIC, L.P. b DE 0.00 3201131.00 3201131.00 0.00 3201131.00 N 6.8 PN General Atlantic Partners 100, L.P. b DE 0.00 3201131.00 3201131.00 0.00 3201131.00 N 6.8 PN GAP Coinvestments III, LLC b DE 0.00 3201131.00 3201131.00 0.00 3201131.00 N 6.8 OO GAP Coinvestments IV, LLC b DE 0.00 3201131.00 3201131.00 0.00 3201131.00 N 6.8 OO GAP Coinvestments V, LLC b DE 0.00 3201131.00 3201131.00 0.00 3201131.00 N 6.8 OO GAP Coinvestments CDA, L.P. b DE 0.00 3201131.00 3201131.00 0.00 3201131.00 N 6.8 PN GAP Coinvestments PE Holdco, L.P. b DE 0.00 3201131.00 3201131.00 0.00 3201131.00 N 6.8 PN GAP Coinvestments PE Holdco GP, L.P. b DE 0.00 3201131.00 3201131.00 0.00 3201131.00 N 6.8 PN GAP Holdings GP, LLC b DE 0.00 3201131.00 3201131.00 0.00 3201131.00 N 6.8 OO General Atlantic (SPV) GP, LLC b DE 0.00 3201131.00 3201131.00 0.00 3201131.00 N 6.8 OO General Atlantic GenPar (Bermuda), L.P. b D0 0.00 3201131.00 3201131.00 0.00 3201131.00 N 6.8 PN General Atlantic GenPar, L.P. b DE 0.00 3201131.00 3201131.00 0.00 3201131.00 N 6.8 PN General Atlantic (KB), L.P. b DE 0.00 3201131.00 3201131.00 0.00 3201131.00 N 6.8 PN GAP (Bermuda) L.P. b D0 0.00 3201131.00 3201131.00 0.00 3201131.00 N 6.8 PN General Atlantic (Lux) S.a r.l. b N4 0.00 3201131.00 3201131.00 0.00 3201131.00 N 6.8 CO General Atlantic GenPar (Lux) SCSp b N4 0.00 3201131.00 3201131.00 0.00 3201131.00 N 6.8 PN General Atlantic Partners (Lux) SCSp b N4 0.00 3201131.00 3201131.00 0.00 3201131.00 N 6.8 PN Korsana Biosciences, Inc. 203 CRESCENT STREET, BLDGS. #3/3A/4, SUITE 503, WALTHAM, MA 02453 This Statement is being filed on behalf of each of the following persons (collectively, the "Reporting Persons"): (i) General Atlantic, L.P. ("GA LP"); (ii) General Atlantic Partners 100, L.P. ("GAP 100"); (iii) GAP Coinvestments III, LLC ("GAPCO III"); (iv) GAP Coinvestments IV, LLC ("GAPCO IV"); (v) GAP Coinvestments V, LLC ("GAPCO V"); (vi) GAP Coinvestments CDA, L.P. ("GAPCO CDA"); (vii) GAP Coinvestments PE Holdco, L.P. ("GAP PE Holdco"); (viii) GAP Coinvestments PE Holdco GP, L.P. ("GAP PE Holdco GP"); (ix) GAP Holdings GP, LLC ("GAP Holdings GP"); (x) General Atlantic (SPV) GP, LLC ("GA SPV"); (xi) General Atlantic GenPar (Bermuda), L.P. ("GenPar Bermuda"); (xii) General Atlantic GenPar, L.P. ("GA GenPar"); (xiii) General Atlantic (KB), L.P. ("GA KB"); (xiv) GAP (Bermuda) L.P. ("GAP Bermuda"); (xv) General Atlantic (Lux) S.a r.l. ("GA Lux"); (xvi) General Atlantic GenPar (Lux) SCSp ("GA GenPar Lux"); and (xvii) General Atlantic Partners (Lux) SCSp ("GAP Lux"). The address of GA LP, GAP 100, GAPCO III, GAPCO IV, GAPCO V, GAPCO CDA, GAP PE Holdco, GAP PE Holdco GP, GAP Holdings GP, GA GenPar, GA SPV and GA KB is c/o General Atlantic Service Company, L.P., 55 East 52nd Street, 33rd Floor, New York, NY 10055. The address of GenPar Bermuda and GAP Bermuda is Clarendon House, 2 Church Street, Hamilton HM 11, Bermuda. The address of GA Lux, GA GenPar Lux and GAP Lux is 412F Route d'Esch, L-1471 Luxembourg. See Row (4) of each Reporting Person's cover page. Y As of September 8, 2026, the Reporting Persons owned the following number of shares of Common Stock, no par value per share (the "common stock"), of Korsana Biosciences, Inc. (the "Company"): (i) GA LP owned of record no shares of common stock or 0.0% of the issued and outstanding shares of common stock. (ii) GAP 100 owned of record no shares of common stock or 0.0% of the issued and outstanding shares of common stock. (iii) GAPCO III owned of record no shares of common stock or 0.0% of the issued and outstanding shares of common stock. (iv) GAPCO IV owned of record no shares of common stock or 0.0% of the issued and outstanding shares of common stock. (v) GAPCO V owned of record no shares of common stock or 0.0% of the issued and outstanding shares of common stock. (vi) GAPCO CDA owned of record no shares of common stock or 0.0% of the issued and outstanding shares of common stock. (vii) GAP PE Holdco owned of record no shares of common stock or 0.0% of the issued and outstanding shares of common stock. (viii) GAP PE Holdco GP owned of record no shares of common stock or 0.0% of the issued and outstanding shares of common stock. (ix) GAP Holdings GP owned of record no shares of common stock or 0.0% of the issued and outstanding shares of common stock. (x) GA SPV owned of record no shares of common stock or 0.0% of the issued and outstanding shares of common stock. (xi) GenPar Bermuda owned of record no shares of common stock or 0.0% of the issued and outstanding shares of common stock. (xii) GA GenPar owned of record no shares of common stock or 0.0% of the issued and outstanding shares of common stock. (xiii) GA KB owned of record 1,366,242 shares of common stock and a pre-funded warrant (the "Pre-Funded Warrant") to purchase 1,834,889 shares of common stock, or 6.8% of the issued and outstanding shares of common stock. (xiv) GAP Bermuda owned of record no shares of common stock or 0.0% of the issued and outstanding shares of common stock. (xv) GA Lux owned of record no shares of common stock or 0.0% of the issued and outstanding shares of common stock. (xvi) GA GenPar Lux owned of record no shares of common stock or 0.0% of the issued and outstanding shares of common stock. (xvii) GAP Lux owned of record no shares of common stock or 0.0% of the issued and outstanding shares of common stock. The limited partners of GA KB that share beneficial ownership of the shares of common stock held by GA KB are the following General Atlantic investment funds: GAP 100, GAP Lux, GAPCO III, GAPCO IV, GAPCO V, GAPCO CDA and GAP PE Holdco. The general partner of GA KB is GA SPV. The general partner of GAP 100 is GA GenPar. The general partner of GAP Lux is GA GenPar Lux, and the general partner of GA GenPar Lux is GA Lux. The sole shareholder of GA Lux is GenPar Bermuda. GA LP, which is controlled by the Partnership Committee of GASC MGP, LLC (the "Partnership Committee"), is the managing member of GAPCO III, GAPCO IV and GAPCO V, the general partner of GAPCO CDA and GA GenPar, and is the sole member of GA SPV. GAP Bermuda, which is also controlled by the Partnership Committee, is the general partner of GenPar Bermuda. GAP Holdings GP, which is also controlled by the Partnership Committee, is the general partner of GAP PE Holdco GP, which is the general partner of GAP PE Holdco. By virtue of the foregoing, the Reporting Persons may be deemed to share voting power and the power to direct the disposition of the shares that each owns of record. As of the date hereof, there are six members of the Partnership Committee. Each of the members of the Partnership Committee disclaims ownership of the shares of common stock reported herein except to the extent that he has a pecuniary interest therein. The name, the address and the citizenship of each of the members of the Partnership Committee as of the date hereof is attached hereto as Schedule A and is hereby incorporated by reference. Amount Beneficially Owned: By virtue of the relationship described above, each of the Reporting Persons may be deemed to beneficially own the shares of common stock indicated on row (9) on such Reporting Person's cover page included herein. The percentages used herein are calculated based upon an aggregate of 47,376,314 shares of common stock, consisting of (i) 45,541,425 shares of common stock reported by the Company to be issued and outstanding as of September 8, 2026 reflected in the Company's Current Report on Form 8-K filed with the U.S. Securities and Exchange Commission on September 11, 2026 and (ii) 1,834,889 shares of common stock issuable upon exercise of the Pre-Funded Warrant. The Reporting Persons' ability to exercise the Pre-Funded Warrant is subject to a blocker provision that will prohibit the Reporting Persons from exercising the Pre-Funded Warrant if such exercise would result in any of the Reporting Persons beneficially owning more than 9.99% of the outstanding shares of common stock at any time, determined in accordance with rules promulgated under the Securities Exchange Act of 1934, as amended. Each of the Reporting Persons may be deemed to have the sole power to direct the voting of the shares of common stock indicated on Row (5) of each such Reporting Person's cover page included herein. Each of the Reporting Persons may be deemed to share the power to direct the voting of the shares of common stock indicated on Row (6) of each such Reporting Person's cover page included herein. Each of the Reporting Persons may be deemed to have the sole power to direct the dispositions of the shares of common stock indicated on Row (7) of each such Reporting Person's cover page included herein. Each of the Reporting Persons may be deemed to share the power to direct the dispositions of the shares of common stock indicated on Row (8) of each such Reporting Person's cover page included herein. Y Y Y N See Item 2, which states the identity of the members of the group filing this Schedule 13G. Y Y Exhibit 1 - Joint Filing Agreement as required by Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended. GENERAL ATLANTIC, L.P. /s/ Michael Gosk 09/18/2026 General Atlantic Partners 100, L.P. /s/ Michael Gosk 09/18/2026 GAP Coinvestments III, LLC /s/ Michael Gosk 09/18/2026 GAP Coinvestments IV, LLC /s/ Michael Gosk 09/18/2026 GAP Coinvestments V, LLC /s/ Michael Gosk 09/18/2026 GAP Coinvestments CDA, L.P. /s/ Michael Gosk 09/18/2026 GAP Coinvestments PE Holdco, L.P. /s/ Michael Gosk 09/18/2026 GAP Coinvestments PE Holdco GP, L.P. /s/ Michael Gosk 09/18/2026 GAP Holdings GP, LLC /s/ Michael Gosk 09/18/2026 General Atlantic (SPV) GP, LLC /s/ Michael Gosk 09/18/2026 General Atlantic GenPar (Bermuda), L.P. /s/ Michael Gosk 09/18/2026 General Atlantic GenPar, L.P. /s/ Michael Gosk 09/18/2026 General Atlantic (KB), L.P. /s/ Michael Gosk 09/18/2026 GAP (Bermuda) L.P. /s/ Michael Gosk 09/18/2026 General Atlantic (Lux) S.a r.l. /s/ Ingrid van der Hoorn 09/18/2026 /s/ William Blackwell 09/18/2026 General Atlantic GenPar (Lux) SCSp /s/ Ingrid van der Hoorn 09/18/2026 /s/ William Blackwell 09/18/2026 General Atlantic Partners (Lux) SCSp /s/ Ingrid van der Hoorn 09/18/2026 /s/ William Blackwell 09/18/2026