This is a multicenter open-label, randomized, non-comparative, parallel cohort pivotal study of treatment with envafolimab (cohort A and C) or envafolimab combined with ipilimumab (cohort B and D) in patients with locally advanced, unresectable or metastatic UPS/MFS who have progressed on one or two lines of chemotherapy. Patients were previously assigned at random into one of two cohorts: cohort A of 80 patients who received single agent envafolimab (300 mg every 3 weeks by subcutaneous (SC) injection) or cohort B of 80 patients who received envafolimab (300 mg every 3 weeks by SC injection) in combination with ipilimumab (1 mg/kg every 3 weeks intravenously for four doses). Following amendment #3, patients will be assigned at random into one of two cohorts: cohort C of 80 patients who will receive single agent envafolimab (600 mg every 3 weeks by subcutaneous (SC) injection) or cohort D of 80 patients who will receive envafolimab 600 mg every 3 weeks by SC injection) in combination with ipilimumab (1 mg/kg every 3 weeks intravenously for four doses). Following amendment #4, enrollment into cohort D was terminated and no further interim analyses will be conducted on this cohort.
