SCHEDULE 13G/A 0001193125-25-282690 0001491072 XXXXXXXX LIVE 1 Common Stock, par value $0.0001 per share 12/31/2025 0001390478 SELLAS Life Sciences Group, Inc. 81642T209 7 TIMES SQUARE, SUITE 2503 NEW YORK NY 10036 Rule 13d-1(b) Anson Funds Management LP TX 0 7481178 0 7481178 7481178 N 4.9 IA PN Anson Management GP LLC TX 0 7481178 0 7481178 7481178 N 4.9 HC OO Tony Moore X1 0 7481178 0 7481178 7481178 N 4.9 HC IN Anson Advisors Inc. Z4 0 7481178 0 7481178 7481178 N 4.9 FI CO Amin Nathoo Z4 0 7481178 0 7481178 7481178 N 4.9 HC IN Moez Kassam Z4 0 7481178 0 7481178 7481178 N 4.9 HC IN SELLAS Life Sciences Group, Inc. 7 TIMES SQUARE SUITE 2503 NEW YORK NY 10036 Anson Funds Management LP, Anson Management GP LLC, Mr. Tony Moore, Anson Advisors Inc., Mr. Amin Nathoo and Mr. Moez Kassam For Anson Funds Management LP, Anson Management GP LLC and Mr. Moore: 16000 Dallas Parkway, Suite 800 Dallas, Texas 75248 For Anson Advisors Inc., Mr. Nathoo and Mr. Kassam: 181 Bay Street, Suite 4200 Toronto, ON M5J 2T3 Anson Funds Management LP is a limited partnership organized under the laws of the State of Texas. Anson Management GP LLC is a limited liability company organized under the laws of the State of Texas. Mr. Moore is a United States citizen. Anson Advisors Inc. is a corporation organized under the laws of Ontario, Canada. Mr. Nathoo and Mr. Kassam are each Canadian citizens. N FI IA HC Canadian Investment Advisor This Amendment No. 1 (this "Amendment") to the Schedule 13G (the "Schedule 13G") is being filed on behalf of Anson Funds Management LP (d/b/a Anson Funds), a Texas limited partnership, Anson Management GP LLC, a Texas limited liability company, Mr. Tony Moore, the principal of Anson Funds Management LP and Anson Management GP LLC, Anson Advisors Inc., an Ontario, Canada corporation, Mr. Amin Nathoo, a director of Anson Advisors Inc., and Mr. Moez Kassam, a director of Anson Advisors Inc., relating to Class A Common Stock, $0.0001 par value (the "Common Stock"), of Sellas Life Sciences Group, Inc., a Delaware corporation (the "Issuer"). This Schedule 13G relates to the Common Stock of the Issuer purchased by one or more private funds to which Anson Funds Management LP and Anson Advisors Inc. serve as co-investment advisors (collectively, the "Funds"). Anson Funds Management LP and Anson Advisors Inc. serve as co-investment advisors to the Funds and may direct the vote and disposition of the 7,481,178 shares of Common Stock held by the Funds. As the general partner of Anson Funds Management LP, Anson Management GP LLC may direct the vote and disposition of the 7,481,178 shares of Common Stock held by the Funds. As the principal of Anson Fund Management LP and Anson Management GP LLC, Mr. Moore may direct the vote and disposition of the 7,481,178 shares of Common Stock held by the Funds. As directors of Anson Advisors Inc., Mr. Nathoo and Mr. Kassam may each direct the vote and disposition of the 7,481,178 shares of Common Stock held by the Funds. Anson Funds Management LP, Anson Management GP LLC, Mr. Moore, Anson Advisors Inc., Mr. Nathoo and Mr. Kassam are the beneficial owners of 4.9% of the outstanding Ordinary Shares, which includes Common Stock underlying outstanding warrants (each, a "Warrant," and collectively, the "Warrants") held by Anson Funds Management LP, Anson Management GP LLC, Mr. Moore, Anson Advisors Inc., Mr. Nathoo and Mr. Kassam. Each Warrant includes a beneficial ownership limitation. The Warrants may not be exercised to the extent the Reporting Persons would, in the case of some of the Warrants, beneficially own more than 4.99% of the outstanding Common Stock. The beneficial ownership set forth herein takes into account the foregoing limitation. This percentage is determined by dividing 7,481,178 by 149,923,417, which is the sum of: (i) 142,442,239 Common Stock issued and outstanding, as reported in the Issuer's Quarterly 10-Q filed with the Securities and Exchange Commission (the "SEC") on November 12, 2025; and (ii) 7,481,178 the number of Common Stock receivable by the Fund upon exercise of the Warrants. See Section 4(a) See Section 4(a) See Section 4(a) See Section 4(a) N Y Y N See Section 4(a) Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and 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. By signing below I certify that, to the best of my knowledge and belief, the foreign regulatory scheme applicable to Anson Advisors Inc. is substantially comparable to the regulatory scheme applicable to the functionally equivalent U.S. institution(s). I also undertake to furnish to the Commission staff, upon request, information that would otherwise be disclosed in a Schedule 13D. Anson Funds Management LP /s/ Tony Moore 02/17/2026 Anson Management GP LLC /s/ Tony Moore 02/17/2026 Tony Moore /s/ Tony Moore 02/17/2026 Anson Advisors Inc. /s/ Amin Nathoo 02/17/2026 /s/ Moez Kassam 02/17/2026 Amin Nathoo /s/ Amin Nathoo 02/17/2026 Moez Kassam /s/ Moez Kassam 02/17/2026