SELLAS Life Sciences Group announced that the Independent Data Monitoring Committee (IDMC) has issued a positive recommendation to continue the Phase 3 REGAL trial of galinpepimut-S (GPS) in acute myeloid leukemia without modification. The IDMC concluded that the risk-benefit profile of GPS supports continued evaluation under the current study protocol, with no safety concerns identified and efficacy data consistent with expectations for continued trial conduct.
Trial Design and Patient Population
The Phase 3 REGAL trial (NCT04229979) is a randomized registrational clinical trial evaluating GPS in AML patients who have achieved complete remission following second-line salvage therapy (CR2 patients). The study completed enrollment in April 2024, with a total of 126 patients randomized. Study sites in the U.S. and Europe accounted for approximately 75% of patients enrolled, with U.S.-based sites representing the highest enrolling country.
The primary endpoint of the survival-driven study is overall survival. The next and final analysis will be triggered once 80 events (deaths) have occurred, which has not yet been reached as of the time of this IDMC review. The final analysis is anticipated by year-end upon occurrence of these 80 events.
IDMC Oversight and Evaluation
The IDMC consists of an independent group of medical, scientific, and biostatistics experts responsible for reviewing and evaluating patient safety and efficacy data for REGAL. The committee monitors quality and overall conduct to ensure the validity, scientific and clinical merits of the study. The IDMC charter provides for periodic reviews of safety, efficacy, and futility in addition to the interim and final analyses.
Therapeutic Target and Mechanism
GPS is licensed from Memorial Sloan Kettering Cancer Center and targets the WT1 protein, which is present in an array of tumor types. The therapy has potential as both a monotherapy and in combination with other therapies to address a broad spectrum of hematologic malignancies and solid tumor indications.
Company Pipeline
SELLAS is also developing SLS009 (tambiciclib), described as potentially the first and best-in-class differentiated small molecule CDK9 inhibitor with reduced toxicity and increased potency compared to other CDK9 inhibitors. Data suggests that SLS009 demonstrated a high response rate in AML patients with unfavorable prognostic factors including ASXL1 mutation, commonly associated with poor prognosis in various myeloid diseases.
