Sellas Life Sciences reports data from Phase 1 study of galinpepimut-S

SELLAS Life Sciences announced topline clinical data from a Phase 1 investigator-sponsored clinical trial of its lead clinical candidate, galinpepimut-S, combined with the checkpoint inhibitor nivolumab in patients with malignant pleural mesothelioma who were either refractory to or relapsed after at least one line of the standard of care therapy. Nine of the ten patients enrolled received at least three doses of GPS, with the third GPS dose given in combination with nivolumab. All enrolled patients had either received and progressed with or were refractory to frontline pemetrexed-based chemotherapy. Additional immune response data from all ten patients is expected by Q4 2023. The study details are as follows: 70.3 weeks median overall survival in patients who received the combination therapy and 54.1 weeks for all ten patients. Median overall survival for patients who entered the study as Stage IV patients was 62.3 weeks. OS was calculated as the time from cessation of the most recent previous therapy until confirmed death or most recent data update for patients who are still alive; 11.9 weeks median progression-free survival for all patients; 30% disease control rate with three patients achieving stable disease per RECIST criteria with the tumor volume decrease of up to 17%; As expected in this high-risk advanced cancer population, all patients experienced adverse events, unrelated and related. Seven out of ten patients had treatment related toxicities and six had nivolumab related toxicities. Grade 3 and higher toxicities were observed in three patients. None of the G3 and higher toxicities were related to GPS. GPS related toxicities were observed in three patients, all were Grade 1 and included G1 skin induration at the site of injection/injection site reaction and/or fatigue in two patients and G1 dizziness and non-cardiac chest pain, each in one patient. Of the ten evaluable patients, eight were male and two were female, with a median age of 69 years; All patients had MPM epithelioid and/or sarcomatoid variant, a tumor which universally expresses Wilms Tumor 1.