CDK9

- Update on the Phase 3 REGAL Clinical Trial of GPS in Acute Myeloid Leukemia (AML) - - Update on the Phase 2a Clinical Trial of SLS009 in relapsed/refractory AML, including topline data - NEW YORK, March 19, 2024 (GLOBE NEWSWIRE) -- SELLAS Life Sciences Group, Inc. (NASDAQ: SLS) (“SELLAS’’ or the “Company”), a late-stage clinical biopharmaceutical company focused on the development of novel therapies for a broad range of cancer indications, today announced that it will host a corporate update call on March 26, 2024, at 8:15 am ET. Angelos Stergiou, MD, ScD h.c., President and CEO of SELLAS will provide an update on the Phase 3 REGAL study of galinpepimut-S (GPS) in AML, as well as the topline data for the 45mg cohort and preliminary data for the 60mg cohort from the Phase 2a study of SLS009 in relapsed/refractory AML. Corporate update call details are as follows: Date: Tuesday, March 26, 2024 Time: 8:15 a.m. Eastern Time Dial-in (U.S.): 1-877-423-9813 International Dial-in: 1-201-689-8573 Webcast: SELLAS Update Call About SELLAS Life Sciences Group, Inc. SELLAS is a late-stage clinical biopharmaceutical company focused on the development of novel therapeutics for a broad range of cancer indications. SELLAS’ lead product candidate, galinpepimut-S (GPS), is licensed from Memorial Sloan Kettering Cancer Center and targets the WT1 protein, which is present in an array of tumor types. GPS has potential as a monotherapy and combination with other therapies to address a broad spectrum of hematologic malignancies and solid tumor indications. The Company is also developing SLS009 , a small molecule, highly selective CDK9 inhibitor, which is licensed from GenFleet Therapeutics (Shanghai), Inc., for all therapeutic and diagnostic uses in the world outside of Greater China. For more information on SELLAS, please visit . Forward-Looking Statements This press release contains forward-looking statements. All statements other than statements of historical facts are “forward-looking statements,” including those relating to future events. In some cases, forward-looking statements can be identified by terminology such as “plan,” “expect,” “anticipate,” “may,” “might,” “will,” “should,” “project,” “believe,” “estimate,” “predict,” “potential,” “intend,” or “continue” and other words or terms of similar meaning. These statements include, without limitation, statements related to the SLS009 clinical development program, including data therefrom, and the timing for release of additional data. These forward-looking statements are based on current plans, objectives, estimates, expectations and intentions, and inherently involve significant risks and uncertainties. Actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties, which include, without limitation, risks and uncertainties with oncology product development and clinical success thereof, the uncertainty of regulatory approval, and other risks and uncertainties affecting SELLAS and its development programs as set forth under the caption “Risk Factors” in SELLAS’ Annual Report on Form 10-K filed on March 16, 2023 and in its other SEC filings. Other risks and uncertainties of which SELLAS is not currently aware may also affect SELLAS’ forward-looking statements and may cause actual results and the timing of events to differ materially from those anticipated. The forward-looking statements herein are made only as of the date hereof. SELLAS undertakes no obligation to update or supplement any forward-looking statements to reflect actual results, new information, future events, changes in its expectations or other circumstances that exist after the date as of which the forward-looking statements were made. Investor Contact Bruce Mackle Managing Director LifeSci Advisors, LLC SELLAS@lifesciadvisors.com

NEW YORK, March 15, 2024 (GLOBE NEWSWIRE) -- SELLAS Life Sciences Group, Inc. (NASDAQ: SLS) (“SELLAS’’ or the “Company”), a late-stage clinical biopharmaceutical company focused on the development of novel therapies for a broad range of cancer indications, today announced that it has entered into definitive agreements with two existing institutional investors for the purchase and sale of 13,029,316 shares of its common stock (or common stock equivalents in lieu thereof) in a registered direct offering and warrants to purchase up to an aggregate of 13,029,316 shares of common stock in a concurrent private placement (together with the registered direct offering, the "Offering") at a combined purchase price of $1.535 per share and accompanying warrant, priced at-the-market under Nasdaq rules. The warrants will have an exercise price of $1.41 per share, will be immediately exercisable upon issuance and will expire 5.5 years from issuance. The closing of the Offering is expected to occur on or about March 19, 2024, subject to the satisfaction of customary closing conditions. The gross proceeds from the Offering are expected to be approximately $20 million, before deducting placement agent fees and other estimated offering expenses. The Company intends to use the net proceeds from the Offering for research and development activities, working capital and general corporate purposes. A.G.P./Alliance Global Partners is acting as sole placement agent for the Offering. The registered direct offering of the shares of common stock (or common stock equivalents in lieu thereof) is being made pursuant to an effective shelf registration statement on Form S-3 (File No. 333-255318) previously filed with the U.S. Securities and Exchange Commission (the “SEC”). A prospectus supplement describing the terms of the proposed Offering will be filed with the SEC and will be available on the SEC’s website located at http://www.sec.gov. Electronic copies of the prospectus supplement may be obtained, when available, from A.G.P./Alliance Global Partners, 590 Madison Avenue, 28th Floor, New York, NY 10022, or by telephone at (212) 624-2060, or by email at prospectus@allianceg.com. The private placement of the warrants will be made in reliance on an exemption from registration under Section 4(a)(2) of the Securities Act and/or Regulation D thereunder. Accordingly, the securities issued in the concurrent private placement may not be offered or sold in the United States except pursuant to an effective registration statement or an applicable exemption from the registration requirements of the Securities Act and such applicable state securities laws. This press release shall not constitute an offer to sell or a solicitation of an offer to buy these securities, nor shall there be any sale of these securities in any state or other jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or other jurisdiction. About SELLAS Life Sciences Group, Inc. SELLAS is a late-stage clinical biopharmaceutical company focused on the development of novel therapeutics for a broad range of cancer indications. SELLAS’ lead product candidate, GPS, is licensed from Memorial Sloan Kettering Cancer Center and targets the WT1 protein, which is present in an array of tumor types. GPS has potential as a monotherapy and combination with other therapies to address a broad spectrum of hematologic malignancies and solid tumor indications. The Company is also developing SLS009 (formerly GFH009), a small molecule, highly selective CDK9 inhibitor, which is licensed from GenFleet Therapeutics (Shanghai), Inc., for all therapeutic and diagnostic uses in the world outside of Greater China. For more information on SELLAS, please visit www.sellaslifesciences.com. Forward Looking Statements This press release contains forward-looking statements. All statements other than statements of historical facts are “forward-looking statements,” including those relating to future events. In some cases, forward-looking statements can be identified by terminology such as “plan,” “expect,” “anticipate,” “may,” “might,” “will,” “should,” “project,” “believe,” “estimate,” “predict,” “potential,” “intend,” or “continue” and other words or terms of similar meaning. These statements include, without limitation, statements related to our ability to close the offering and the gross proceeds from the offering. These forward-looking statements are based on current plans, objectives, estimates, expectations and intentions, and inherently involve significant risks and uncertainties. Actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties, which include, without limitation, risks and uncertainties set forth under the caption “Risk Factors” in SELLAS’ Annual Report on Form 10-K filed on March 16, 2023 and in its other SEC filings. Other risks and uncertainties of which SELLAS is not currently aware may also affect SELLAS’ forward-looking statements and may cause actual results and the timing of events to differ materially from those anticipated. The forward-looking statements herein are made only as of the date hereof. SELLAS undertakes no obligation to update or supplement any forward-looking statements to reflect actual results, new information, future events, changes in its expectations or other circumstances that exist after the date as of which the forward-looking statements were made. Investor Contact Bruce Mackle Managing Director LifeSci Advisors, LLC SELLAS@lifesciadvisors.com

NEW YORK, March 08, 2024 (GLOBE NEWSWIRE) -- SELLAS Life Sciences Group, Inc. (NASDAQ: SLS) (“SELLAS’’ or the “Company”), a late-stage clinical biopharmaceutical company focused on the development of novel therapies for a broad range of cancer indications, today announced that it has streamlined its executive leadership to further focus on advancing the Company’s clinical programs while optimizing resource allocation. As part of this effort, Senior Vice President, Chief Commercial Officer, Robert Francomano and Executive Vice President, General Counsel and Corporate Secretary, Barbara Wood, will be departing the Company. “As part of our efforts to rapidly advance our clinical pipeline, we continue to streamline our operations to effectively and efficiently deliver on our key business objectives,” said Angelos Stergiou, MD, ScD h.c., President and Chief Executive Officer of SELLAS. “As I mentioned on the January shareholder call, our focus remains on shareholder value through the development of our assets and tight financial stewardship and exploration of commercial partnerships with the assistance of Stifel Financial Corp. I am confident that SELLAS has the right leadership in place to drive forward all of our clinical programs and I look forward to upcoming interim analysis of the Phase 3 REGAL trial of GPS in AML and reporting topline data from our Phase 2a SLS009 r/r AML trial this quarter and additional data in the second quarter, and topline data from the Phase 1b/2 study of SLS009 in PTCL in the second quarter. Additionally, we made significant strides in commercial market access, pricing strategies, and reimbursement initiatives positioning SELLAS for continued success in the Phase 3 REGAL trial of GPS and its potential as a new treatment for AML patients.” Dr. Stergiou continued: “I would like to thank Robert and Barbara for their leadership, dedication, and unwavering contributions to help bring SELLAS to this point of development. I wish them the very best in their future endeavors.” In line with the Company’s commitment to maintaining operational excellence, SELLAS is engaging the expertise of a seasoned commercial consultant with a proven track record of success, including launching Venetoclax. Stacy Yeung, recently promoted to Vice President, Associate General Counsel, and Head of Compliance, with 20 years of relevant experience will lead the Company’s legal and compliance functions. About SELLAS Life Sciences Group, Inc. SELLAS is a late-stage clinical biopharmaceutical company focused on the development of novel therapeutics for a broad range of cancer indications. SELLAS’ lead product candidate, GPS, is licensed from Memorial Sloan Kettering Cancer Center and targets the WT1 protein, which is present in an array of tumor types. GPS has potential as a monotherapy and combination with other therapies to address a broad spectrum of hematologic malignancies and solid tumor indications. The Company is also developing SLS009 (formerly GFH009), a small molecule, highly selective CDK9 inhibitor, which is licensed from GenFleet Therapeutics (Shanghai), Inc., for all therapeutic and diagnostic uses in the world outside of Greater China. For more information on SELLAS, please visit www.sellaslifesciences.com. Forward-Looking Statements This press release contains forward-looking statements. All statements other than statements of historical facts are “forward-looking statements,” including those relating to future events. In some cases, forward-looking statements can be identified by terminology such as “plan,” “expect,” “anticipate,” “may,” “might,” “will,” “should,” “project,” “believe,” “estimate,” “predict,” “potential,” “intend,” or “continue” and other words or terms of similar meaning. These statements include, without limitation, statements related to the GPS clinical development program and the timing for achievement of milestones. These forward-looking statements are based on current plans, objectives, estimates, expectations and intentions, and inherently involve significant risks and uncertainties. Actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties, which include, without limitation, risks and uncertainties with oncology product development and clinical success thereof, the uncertainty of regulatory approval, and other risks and uncertainties affecting SELLAS and its development programs as set forth under the caption “Risk Factors” in SELLAS’ Annual Report on Form 10-K filed on March 16, 2023 and in its other SEC filings. Other risks and uncertainties of which SELLAS is not currently aware may also affect SELLAS’ forward-looking statements and may cause actual results and the timing of events to differ materially from those anticipated. The forward-looking statements herein are made only as of the date hereof. SELLAS undertakes no obligation to update or supplement any forward-looking statements to reflect actual results, new information, future events, changes in its expectations or other circumstances that exist after the date as of which the forward-looking statements were made. Investor Contact Bruce Mackle Managing Director LifeSci Advisors, LLC SELLAS@lifesciadvisors.com