(RTTNews) - SELLAS Life Sciences Group Inc. (SLS) reported that survival in its pivotal Phase 3 REGAL trial is extending longer than anticipated, delaying the occurrence of the 80th event required to trigger the final overall survival analysis.
The REGAL study is evaluating Galinpepimut-S (GPS) as a maintenance therapy for patients with acute myeloid leukemia (AML) who have achieved a second complete remission (CR2). As of December 26, 2025, the company's contract research organization informed SELLAS that 72 events had occurred ¬-short of the 80 deaths needed for the final analysis under the statistical plan. SELLAS remains fully blinded to efficacy and survival outcomes.
Patients enrolled in REGAL are those unable to undergo transplant after achieving CR2, a group typically treated with hypomethylating agents and/or BCL-2 inhibitors. Median overall survival in this setting is generally around eight months, underscoring the significant unmet need.
GPS, a WT1-targeting immunotherapeutic licensed from Memorial Sloan Kettering, is being studied for its potential to extend survival in this difficult-to-treat population.
The Independent Data Monitoring Committee (DMC) previously recommended in August 2025 that the trial continue without modification. Because the REGAL trial is event-driven, SELLAS will announce when the 80th event occurs, after which the study will be unblinded, and final analyses will begin.
SELLAS noted that no interim efficacy analyses have been conducted and no statistical penalties have been incurred. The company added that longer-than-expected survival may increase the probability of a positive outcome, as highlighted by key opinion leaders during its recent R&D event.
Beyond GPS, SELLAS continues to advance SLS009 (tambiciclib), a highly selective CDK9 inhibitor now in a Phase 2a trial for relapsed or refractory AML in patients who failed or stopped responding to venetoclax-based therapy. The program follows a completed Phase 1 study in hematologic malignancies, with an additional monotherapy study ongoing in relapsed or refractory peripheral T-cell lymphoma.
SLS has traded between $0.85 and $3.43 over the past year. The stock closed yesterday's trading at $3.35, up 16.72%.
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