SELLAS informed of an update of its Phase 3 REGAL trial

Announcement

SELLAS Life Sciences Group, Inc., a leading late-stage clinical biopharmaceutical company focused on the establishment of novel therapies for a wide range of cancer indications have an update to announce for its ongoing Phase 3 REGAL trial. The trial assessed GPS as a capable maintenance therapy in patients suffering from AML after the second complete remission (CR2). As per the Independent Data Monitoring Committee (IDMC) advice in August 2025, the Phase 3 REGAL trial has a certain consistency without modification.

Following this, it was predicted that the 80th death event would provoke the final analysis that might come into force before year-end. The REGAL trial is a promising overall survival study, and according to a statistical analysis plan, the final evaluation will be prompt after the 80 events (death) takes place. This

SELLAS take on the study, recommendation and events

The company’s contract research organisation managing team made the company aware of the REGAL trial event number, which has reached 72 on 26th December 2025. SELLAS stayed unfolded to all the survival and efficacy data outcomes. Alongside, no statistical penalty was pursued, and no outcome analyses were conducted.

As this one-time update on the estimated number of events does not affect future statistical evaluation due to the final analysis. The final analysis is event-based, and the timeframe of studies with overall survival (OS) as an endpoint can be differentiated. Furthermore, the company will inform about the 80th event when occurred.

MD, ScD, h.c., Chief Executive Officer and President of SELLAS, Angelos Stergiou, said, “We value the consistent dedication of the families, investigators and patients' involvement in the vital Phase 3 REGAL trial. As the survival time for the caregivers and patients were extended than expected. Though the 80th event hasn’t yet taken place, and so we are blinded, as each month may elevate the portability of a progressive study, as spotlighted by the main opinion leaders associated with our latest R&D event.”

“The definitive data will follow the analyses and unblinding of the study results. We stay steadfast and consistent in our commitment to modernise the groundbreaking therapies like GPS. The GPS that holds the potential to meaningfully improve the quality of life of the patients with AML.” The Director of Hematologic Malignancies Research at Texas Oncology, Baylor University Medical Center and a member of the REGAL Steering Committee, Dr Yair Levy, also expressed its view towards the initiative to assess GPS as a novel therapeutic idea in an AML group.