A combination of ipilimumab and the granulocyte-macrophage colonystimulating factor-transduced allogeneic prostate cancer cells vaccine (GVAX) was feasible and tolerable in an openlabel phase 1 study in men with metastatic castration-resistant prostate cancer (van den Eertwegh AJM, et al. Lancet Oncol. 2012;13:509-517). Based on the toxicity profile and clinical activity, the authors recommended further clinical evaluation of ipilimumab and tumor vaccines in combination.
After a GVAX intradermal priming dose, patients received additional doses every 2 weeks for 24 weeks, for a total of 13 injections. They received intravenous infusions of ipilimumab 0.3, 1.0, 3.0, or 5.0 mg/kg every 4 weeks, for a total of 6 infusions, each administered on the same day as a vaccination. The primary end point was the safety of GVAX. No severe immune-related adverse events (AEs) were reported with the lowest 2 doses. The most common AEs were injection-site reactions, fatigue, and pyrexia.
Clinical activity included durable prostate-specific antigen responses, bone scan improvements, and tumor regression.
