NEW YORK, December 30, 2025, 01:49 ET — Market closed
- Shares of SELLAS Life Sciences Group closed up 16.7% on Monday at $3.35 after a late-stage AML trial update.
- The company said 72 of the 80 required “events” (deaths) had occurred as of Dec. 26, keeping the study short of its final analysis trigger.
- Focus now turns to the timing of the 80th event and the eventual unblinding of overall survival results.
SELLAS Life Sciences Group Inc (SLS) shares jumped 16.7% on Monday to close at $3.35 after the company updated investors on the timing of a late-stage acute myeloid leukemia (AML) trial. The stock traded between $2.60 and $3.44 and logged about 22.4 million shares, according to StockAnalysis data.
The update matters because REGAL is the company’s main near-term catalyst, and the market is trying to pin down when the final dataset will be ready. In biotech, a change in timing can move shares even when there is no new efficacy data.
In a release issued at 8:35 a.m. ET on Monday, SELLAS said its contract research organization counted 72 events — deaths in an “overall survival” study, a measure of how long patients live — in its Phase 3 REGAL trial (NCT04229979) as of Dec. 26. SELLAS had expected to reach 80 events before year-end, the milestone that triggers the final analysis, but said it remains blinded to outcomes and did not conduct an outcomes analysis as part of the one-time check. Chief Executive Angelos Stergiou said “every passing month may increase the probability of a successful study.” Sellas Life Sciences
An event-driven trial does not lock in an end date; it waits until a preset number of outcomes occurs before comparing the treatment groups. “Blinded” means the company does not know which group is doing better until the trial is unsealed.
REGAL is testing galinpepimut-S, or GPS, as a maintenance therapy — treatment aimed at keeping cancer from returning after a remission — in AML patients in a second complete remission. The trial’s primary endpoint is overall survival, the company said.
SELLAS said the study involves patients who are unable to undergo a transplant, a common intensification step in AML that is not feasible for all patients. Dr. Yair Levy of Texas Oncology Baylor University Medical Center, a member of the REGAL steering committee, said treatment in that setting typically uses hypomethylating agents and/or a BCL-2 inhibitor, with expected median overall survival of around eight months.
Investors often read a slower event count as a hint that patients are living longer, but the signal is not clean. Because the tally is pooled and the company is blinded, the update does not show whether GPS is outperforming the control arm.
That leaves traders with a binary setup: a delayed event trigger extends uncertainty, while also keeping attention on the eventual unblinding and final analysis. The sharp move on Monday underscored how sensitive small-cap biotech stocks can be to trial-timing headlines.
Before the next session, attention stays on the countdown to the 80th event, which would open the door to unblinding and a final comparison of overall survival. Until that milestone is reached, trading is likely to hinge more on risk appetite than on new clinical data.
Market calendars are also in focus. MarketBeat lists an estimated next earnings date of March 19, 2026 — before the market opens — and notes SELLAS has not confirmed the timing.
