A phase 1 dose-escalation study of intraperitoneal cisplatin, intravenous/intraperitoneal paclitaxel, bevacizumab, and olaparib for newly diagnosed ovarian cancer

Abstract

Objective: We assessed the safety and maximum tolerated dose (MTD) of the poly ADP-ribose polymerase (PARP) inhibitor olaparib with intravenous (IV)/intraperitoneal (IP) cisplatin/paclitaxel and IV bevacizumab, followed by olaparib and bevacizumab maintenance, in patients with newly diagnosed ovarian cancer who had undergone primary debulking surgery.

Methods: Treatment included: (Cycles 1-6) Day 1, IV paclitaxel 135 mg/m²/3 h + (from Cycle 2 onward) bevacizumab 15 mg/kg; Day 2, IP cisplatin 75 mg/m²; Days 2-8, olaparib (50/100/200 mg BID); Day 8, IP paclitaxel 60 mg/m² of a 21-day cycle. Maintenance (Cycles 7-22) included: olaparib 300 mg BID and bevacizumab 15 mg/kg Day 1. The primary endpoint was MTD of olaparib, chemotherapy, and bevacizumab.

Results: Seventeen women were treated (Cohort 1 [50 mg olaparib], 8 patients; Cohort 2 [100 mg], 3 patients; and Cohort 3 [200 mg], 6 patients). Median age was 57 years (47-73); 94% had stage III disease; 29% had a germline BRCA mutation. Two of 6 patients in Cohort 3 experienced a dose-limiting toxicity (DLT). Grade 3/4 toxicities included: neutropenia (56%), lymphopenia (31%), anemia (25%), and fatigue (19%). Most patients started (88%, 81%) and completed (75%, 50%) maintenance olaparib and bevacizumab, respectively; 36% of patients on olaparib maintenance required a dose reduction. Median PFS was 33 months (26.2-NA).

Conclusions: The MTD of intermittently dosed olaparib with concurrent IV/IP cisplatin/paclitaxel and bevacizumab is 100 mg BID. Non-hematologic toxicities were predominantly low grade. One-third of patients on olaparib maintenance required dose reduction.

Keywords: Bevacizumab; Maintenance therapy; Olaparib; Ovarian cancer; PARP inhibitors; Phase 1.