SELLAS Life Sciences Group Inc. (SLS) shares rallied Monday after shaking off early premarket weakness, climbing as investors digested a clinical trial update that suggests things might be going better than planned.
The Trial Update
The biotech company provided fresh details on its Phase 3 REGAL trial, which is evaluating GPS as a maintenance treatment for acute myeloid leukemia patients who've reached a second complete remission. According to SELLAS, the contract research organization running the study reported 72 events had occurred as of December 26, 2025.
Here's where it gets interesting: The trial measures overall survival, and the final analysis kicks off once 80 events—that is, patient deaths—have been recorded per the statistical plan. Back in August, the company expected to hit that 80-event milestone before year-end, based on recommendations from the Independent Data Monitoring Committee to continue the trial unchanged.
Why the Delay Might Be Good News
The fact that the 80th event hasn't happened yet could actually be encouraging. Longer survival times mean patients are living beyond initial projections, which could boost the odds of demonstrating a meaningful treatment benefit.
"We appreciate the continued dedication of the patients, families, and investigators participating in the pivotal Phase 3 REGAL trial where survival times, fortunately for patients and caregivers, appear longer than expected," said Angelos Stergiou, president and CEO of SELLAS. "While the 80th event has not yet occurred, and we remain fully blinded, every passing month may increase the probability of a successful study as highlighted by key opinion leaders in our recent R&D event."
Dr. Yair Levy, director of Hematologic Malignancies Research at Texas Oncology Baylor University Medical Center and a REGAL Steering Committee member, added: "We hope to see an extended survival benefit, with a tolerable safety profile, as observed in previous GPS studies."
Stock Performance
SELLAS shares were up 16.72% at $3.35 at the time of publication Monday, hitting a new 52-week high.
