SELLAS Announces First Patient Dosed in Phase Ib/II Trial of SLS009 (GFH009) in Relapsed/Refractory Peripheral T-cell Lymphomas

NEW YORK, Oct. 11, 2023 (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 its partner GenFleet Therapeutics (Shanghai), Inc. has dosed the first patient in a Phase Ib/II trial evaluating SLS009 (GFH009) in relapsed/refractory Peripheral T-cell Lymphomas (PTCL). The open-label, single-arm trial will enroll up to 95 patients to evaluate safety and efficacy and, based on the results, may serve as a registrational study. This initial PTCL study is fully funded by GenFleet and is being conducted in China.

“SLS009 is a novel and highly selective CDK9 inhibitor which, to date, has shown tremendous therapeutic promise across multiple blood cancers,” said Angelos Stergiou, MD, ScD h.c., President and Chief Executive Officer of SELLAS. “We are pleased with the initiation of the Phase Ib/II trial of SLS009 in the underserved PTCL patient population. Collaborating with GenFleet amplifies the potential of our highly selective CDK9 inhibitor in multiple indications and reflects our joint commitment to delivering this groundbreaking treatment to cancer patients globally. While our primary efforts are focused on acute myeloid leukemia (AML) in the United States, we remain fully supportive and deeply involved in the PTCL study and will make further development decisions for this indication as we obtain initial data for this Phase Ib/II study from our partner.”

SLS009 demonstrated favorable safety/tolerability and promising clinical efficacy in the recently completed dose-escalation portion of the Phase I trial in relapsed/refractory hematological malignancies. Complete or partial responses were observed in AML and lymphoma patients among which four PTCL patients (36.4%) achieved clinical responses.

In March 2022, SELLAS and GenFleet Therapeutics (Shanghai), Inc. entered into an exclusive license agreement that grants rights to SELLAS for the development and commercialization of SLS009 (GFH009), a highly selective small molecule CDK9 inhibitor, across all therapeutic and diagnostic uses worldwide outside of Greater China (mainland China, Hong Kong, Macau, and Taiwan).

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 (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 SLS009 clinical development program, including clinical data of SLS009 and plans for further development of SLS009. 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