X0202 SCHEDULE 13G 0001839209 XXXXXXXX LIVE Ordinary Shares, nominal value DKK 1 per share 09/28/2026 0001434265 GENMAB A/S 372303206 TOLDBODGADE 33 1253 COPENHAGEN K G7 00000 Rule 13d-1(c) Darwin Global Management, Ltd. Y9 0.00 3668310.00 0.00 3668310.00 3668310.00 N 5.9 IA OO Consists of (i) 1,825,006 Ordinary Shares and (ii) 18,433,047 ADSs representing 1,843,304 Ordinary Shares. Dr. Abhishek Trehan X0 0.00 3668310.00 0.00 3668310.00 3668310.00 N 5.9 IN Consists of (i) 1,825,006 Ordinary Shares and (ii) 18,433,047 ADSs representing 1,843,304 Ordinary Shares. Darwin Global Master Fund, Ltd. E9 0.00 3569746.00 0.00 3569746.00 3569746.00 N 5.7 OO Consists of (i) 1,775,809 Ordinary Shares and (ii) 17,939,370 ADSs representing 1,793,937 Ordinary Shares. GENMAB A/S Carl Jacobsens Vej 30, 2500 Valby, Denmark This statement is filed by: (i) Darwin Global Management, Ltd., a limited company incorporated under the laws of Jersey ("Darwin Global"), with respect to the ordinary shares, nominal value DKK 1 per share ("Ordinary Shares"), of Genmab A/S, a public limited liability company incorporated under the laws of Denmark (the "Company"), directly held by, and represented by the American Depositary Shares ("ADSs") of the Company directly held by, (a) Master Fund (as defined below), to which Darwin Global serves as investment manager, and (b) segregated accounts (the "Segregated Accounts") for which Darwin Global serves as an appointed sub-investment advisor; (ii) Dr. Abhishek Trehan ("Dr. Trehan"), the Chief Investment Officer and the controlling person of Darwin Global, with respect to the Ordinary Shares directly held by, and represented by ADSs directly held by, each of Master Fund and the Segregated Accounts; and (iii) Darwin Global Master Fund Ltd. ("Master Fund"), a Cayman Islands exempted company, with respect to the Ordinary Shares directly held by, and represented by ADSs directly held by, it. The foregoing persons are hereinafter sometimes each referred to as a "Reporting Person" and collectively referred to as the "Reporting Persons." The filing of this statement should not be construed as an admission that any Reporting Person is, for purposes of Section 13 of the Securities Exchange Act of 1934, the beneficial owner of the securities reported herein. There is no CUSIP assigned to the Ordinary Shares. The CUSIP number 372303206 has been assigned to the ADSs, which are quoted on The Nasdaq Stock Market LLC under the symbol "GMAB". Each ADS represents ownership of one tenth of one Ordinary Share. The address of the business office of each of the Reporting Persons is Whiteley Chambers, Don Street, St. Helier, Jersey JE2 4TR. Darwin Global is a Jersey limited company. Dr. Trehan is a British citizen. Master Fund is a Cayman Islands exempted company. Y The information required by Item 4(a) is set forth in Row 9 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The percentage set forth in this Schedule 13G is calculated based upon an aggregate of 62,405,855 Ordinary Shares, reported to be outstanding in Exhibit 99.1 to the Form 6-K filed with the SEC on September 9, 2026. 5.9% The information required by Item 4(c)(i) is set forth in Row 5 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The information required by Item 4(c)(ii) is set forth in Row 6 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The information required by Item 4(c)(iii) is set forth in Row 7 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The information required by Item 4(c)(iv) is set forth in Row 8 of the cover page for each of the Reporting Persons and is incorporated herein by reference. Y N See Item 2(a). 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 99: Joint Filing Agreement Darwin Global Management, Ltd. /s/ John Legge 10/05/2026 Dr. Abhishek Trehan /s/ Dr. Abhishek Trehan 10/05/2026 Darwin Global Master Fund, Ltd. /s/ John Legge 10/05/2026