Study on MK-3475 Plus Chemotherapy Versus Chemotherapy Alone in Recurrent, Platinum-resistant Ovarian Cancer

This is a multicenter, randomized, open-label trial, designed to assess the therapeutic efficacy and toxicity of the combination chemotherapy with pembrolizumab in recurrent, platinum resistant OC patients. The main objective is to test whether the therapeutic intervention benefits the patients evaluating the increase in overall survival with respect to chemotherapy alone. Eligible patients will be randomized 1:1 to receive: ARM A: Pegylated Liposomal Doxorubicin 40 mg/mq iv q 28 Weekly Paclitaxel 80 mg/mq d 1,8,15 q 28 Gemcitabine 1000 mg/mq d 1,8 q 21 At physician' discretion or ARM B: Pegylated Liposomal Doxorubicin 40 mg/mq iv q 28 Weekly Paclitaxel 80 mg/mq d 1,8,15 q 28 Gemcitabine 1000 mg/mq d 1,8 q 21 plus Pembrolizumab 200 mg d1 q 21 iv infusion in 30 minutes In both arms patients will receive treatments until disease progression, unacceptable toxicity of patient's refusal. Patients will receive at least 6 to 8 cycles of chemotherapy at physician's discretion. In the experimental arm patients who stop chemotherapy for toxicity reasons and whose disease is at least in stabilization, may continue treatment with Pembrolizumab as single agent. Patients will be stratified according to the number of previous chemotherapy lines (1 vs \>1) and measurable/evaluable disease.