A phase 2, single-arm study of an autologous dendritic cell treatment against mucin 1 in patients with advanced epithelial ovarian cancer

BACKGROUND Mucin 1 antigen, highly expressed by epithelial ovarian cancer (EOC), is a potential target for immunotherapy. A previous successful phase 1 trial was conducted in patients with adenocarcinoma who were injected with Cvac, autologous monocyte-derived dendritic cells (DCs) incubated with mannosylated mucin 1 protein (M-FP). The present study was a phase 2 trial of Cvac in patients with advanced EOC. METHODS Eligible patients had EOC with progressive disease, defined as an increase in CA125 of ≥ 25% in 1 month. The primary endpoint was CA125 response or stabilization. Peripheral blood mononuclear cells were collected by leukapheresis and cultured to generate DCs. The DC were incubated with M-FP, and after washing were prepared for injection into the patient intradermally every 4 weeks for 3 doses, then every 10 weeks for up to 12 months. RESULTS All 28 patients recruited were evaluable for safety and 26 for efficacy. All had undergone surgery and platinum-based chemotherapy, and 57% of patients received ≥ 3 chemotherapy regimens. There were no Grade 3 or 4 toxicities considered related to Cvac. Four patients showed CA125 response or stabilization (2 patients with major responses, 1 minor response, 1 stabilization) of median duration 10.3 months (5.3-16.3 months). An additional patient had > 25% CA125 reduction (not confirmed). CONCLUSIONS Cvac immunotherapy was well tolerated. Clinical activity in EOC was evident based on decline or stabilization of CA125 in some patients, supporting ongoing development of Cvac in ovarian carcinoma and planning of additional trials of patients in remission is currently underway.