SELLAS Life Sciences Group, Inc.

We are a late-stage clinical biopharmaceutical company focused on developing new treatments for various cancer types. Our main product candidates are galinpepimut-S (GPS) and SLS009 (tambiciclib). GPS is a peptide immunotherapy targeting the Wilms tumor 1 (WT1) antigen, licensed from Memorial Sloan Kettering Cancer Center. The WT1 protein is found in 20 or more cancer types. GPS is designed to work as a standalone treatment or in combination with other immunotherapies for blood cancers and solid tumors. We are conducting an open-label, randomized Phase 3 clinical trial, called the REGAL study, for GPS as a monotherapy. This study involves patients with acute myeloid leukemia (AML) in the maintenance setting after achieving second complete remission (CR2) following second-line antileukemic therapy. Patients are randomly assigned to receive either GPS or best available treatment (BAT). The REGAL study's primary goal is to measure overall survival (OS). We planned to enroll approximately 125 to 140 patients across about 95 clinical sites in North America, Europe, and Asia. An interim analysis for safety, efficacy, and futility was planned after 60 events (deaths). Enrollment for the study was completed in March 2024. In December 2024, the pre-specified threshold of 60 events (deaths) was reached, initiating the interim analysis by the Independent Data Monitoring Committee (IDMC). In January 2025, the IDMC completed its interim analysis and recommended that the study continue without changes. Our second product candidate, SLS009 (tambiciclib), is a highly selective small molecule cyclin-dependent kinase 9 (CDK9) inhibitor.