Phase I study of olaparib in combination with carboplatin and/or paclitaxel in patients with advanced solid tumors.

Abstract

2579 Background: This three-center phase I study evaluated the PARP1/2 inhibitor olaparib (O) in combination with carboplatin (C), paclitaxel (Pa) or both (CPa) in patients (pts) with advanced solid tumors refractory to standard therapies (NCT00516724). Methods: This ongoing study consists of multiple parts (P) in which escalating doses of O capsule and tablet formulations were studied. Capsule formulation data are presented; continuous O with C (P1; 21 day cycle), CPa (P2a; 21 day cycle) and weekly Pa (P2b; 28 day cycle) or intermittent O with CPa (P3; 21 day cycle). Primary and secondary objectives were safety/tolerability and antitumor activity (RECIST), respectively. Results: This analysis (non validated data) included 87 enrolled pts (P1 [n=25] P2a [n=20] P2b [n=12] and P3 [n=30]). Most common tumor types were breast (26%), melanoma (10%) and ovarian (7%). 12 pts had known gBRCA1/2 mutations. A tolerable continuous dosing schedule of O with CPa was not determined. Most common AEs (all grades) were myelosuppression (71%) notably neutropenia (54%) and thrombocytopenia (26%), and fatigue (77%). Excessive treatment cycle delays due to hematologic toxicity occurred with continuous O combined with standard doses of C or CPa. Two doses were identified as tolerable: continuous O 100 mg bd with weekly Pa 80 mg/m2 and intermittent O 200 mg bd (d1–10) with CPa AUC4/175 mg/m2 q 3 weeks. 14/87 pts (16%) had an objective response (complete response [CR] 5%; partial response [PR] 11%); 28% had stable disease for ≥4 months. Activity appeared greater in pts with BRCA1/2 mutations (CR 17%; PR 33%). Conclusions: Continuous O in combination with CPa exacerbated hematologic toxicities leading to schedule delays. Tolerability improved with intermittent O. Antitumor activity was highest in pts with a BRCA1/2 mutation. This study identified two tolerable O capsule treatment schedules for further development. Clinical trial information: NCT00516724. [Table: see text]