SELLAS Life Sciences Announces Positive Recommendation of Independent Data Monitoring Committee Following Completion of Enrollment in REGAL Phase 3 Study

– Based on the Efficacy and Safety Data Assessed, the Independent Data Monitoring Committee (IDMC) Recommends Continuation of Phase 3 REGAL Trial Patients Treatment and Follow-Up Without Any Modifications –

– IDMC Will Convene Again Ahead of Scheduled IDMC Charter Meeting –

– Next Efficacy and Safety Assessment of All REGAL Patients (n=127) in June 2024 –

NEW YORK, April 29, 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 a positive review of the ongoing Phase 3 REGAL clinical trial of galinpepimut-S (GPS) in acute myeloid leukemia (AML) by the Independent Data Monitoring Committee (IDMC). The IDMC conducted a prespecified risk-benefit assessment of unblinded data from the study and has recommended that the trial continue without modifications, and scheduled its next meeting in June 2024, earlier than prescribed in the IDMC charter schedule to review the most up-to-date information regarding the number of events (deaths) required for triggering prespecified interim analysis.

“We thank the IDMC members for the work and their guidance to continue the Phase 3 REGAL trial patients’ treatment without any modifications,” said Angelos Stergiou, MD, ScD hc, President and Chief Executive Officer of SELLAS. “This recommendation was made based on the assessment of efficacy and safety of the accumulated data. We are pleased with the recently concluded enrollment for the study in the US, Europe, and Asia, per the predetermined statistical analysis plan, and we look forward to the interim analysis potentially later this quarter. If approved, GPS would be a promising new treatment in this severely underserved indication.”

“As reported in March 2024, the REGAL Study Steering Committee reviewed the blinded study data with 66 patients discontinuing the treatment. In the trial, patients are recorded as having stopped the study treatment in cases of death for any reason, relapse, intolerable toxicity, or treatment completion. Regarding the GPS arm, we are pleased to report that we have not observed any intolerable toxicities in any patient population across all our clinical studies thus far, although toxicities are commonly observed with therapies used in the control arm. The IDMC also confirmed no safety issues in their recent review. Therefore, patients off treatment likely either relapsed or passed away, but as the study sponsor, we lack information on the actual number of events (60 events are required for interim analysis). This lies within the purview of the IDMC, which will now meet again in June and will review both efficacy and safety data from all enrolled REGAL patients (n=127) with a data cut-off date of around the end of May. At this point I would like to thank again all our global investigators who enrolled high numbers of patients with the top three enrolling countries, the US, Greece, and India, leading the way as a testament to the broad appeal of GPS.”