Positive Signals Mount as SELLAS GPS Trial Shows Stronger-Than-Expected Patient Survival Outcomes

SELLAS Life Sciences (SLS) is making waves in the biotech space with its ongoing Phase 3 REGAL trial examining Galinpepimut-S (GPS) for acute myeloid leukemia (AML) patients. The continued progress in the trial reveals an encouraging development: patients are living longer than initially projected, which is pushing back the timeline for reaching the 80 death events needed to complete the final survival analysis.

Trial Progress Indicates Extended Lifespans

As of late December 2025, SELLAS had recorded 72 of the required 80 events, signaling that enrolled patients are experiencing extended survival periods. This delay, while extending the trial timeline, carries significant clinical implications. The REGAL study targets AML patients who have achieved a second complete remission but cannot undergo transplantation—a population typically facing a median overall survival of around eight months with standard hypomethylating agents or BCL-2 inhibitors.

Why Longer Survival Matters for Drug Development

When a therapy keeps patients alive longer than historical benchmarks, it fundamentally changes the risk-benefit calculation. The Independent Data Monitoring Committee endorsed trial continuation in August 2025 without modifications, suggesting confidence in the approach. Industry experts have noted that extended survival outcomes like these often correlate with positive efficacy results—a dynamic that could bolster GPS’s chances of demonstrating meaningful clinical benefit.

GPS itself represents a novel immunotherapy mechanism: it targets WT1 (Wilms tumor antigen), licensed from Memorial Sloan Kettering, to potentially activate immune responses against leukemia cells in this difficult-to-treat population.

Broader Pipeline Advancement

Beyond GPS, SELLAS continues building its hematologic oncology portfolio. The company is advancing SLS009 (tambiciclib), a selective CDK9 inhibitor currently in Phase 2a trials for relapsed or refractory AML in patients who failed venetoclax-based therapy. Additional studies are exploring the compound in peripheral T-cell lymphoma, expanding the potential market opportunity.

Market Perspective

SLS stock has ranged from $0.85 to $3.43 over the past twelve months, with shares closing at $3.35 yesterday—up 16.72%. The market appears to be pricing in optimism around the continued clinical progress, though investors remain focused on the actual 80th event announcement and subsequent trial unblinding.

The company remains fully blinded to efficacy data, maintaining trial integrity until the final analysis begins post-unblinding. With no interim analyses conducted and no statistical penalties incurred, all eyes now turn toward the eventual readout.