Overall survival and updated progression-free survival outcomes in a randomized phase II study of combination cediranib and olaparib versus olaparib in relapsed platinum-sensitive ovarian cancer

Background: Olaparib is a poly(ADP-ribose) polymerase inhibitor and cediranib is an oral anti-angiogenic. In the primary analysis of this phase II study, combination cediranib/olaparib improved progression-free survival (PFS) compared with olaparib alone in relapsed platinum-sensitive ovarian cancer. This updated analysis was conducted to characterize overall survival (OS) and update PFS outcomes. Patients and methods: Ninety patients were enrolled to this randomized, open-label, phase II study between October 2011 and June 2013 across nine United States-based academic centers. Data cut-off was 21 December 2016, with a median follow-up of 46 months. Participants had relapsed platinum-sensitive ovarian cancer of high-grade serous or endometrioid histology or had a deleterious germline BRCA1/2 mutation (gBRCAm). Participants were randomized to receive olaparib capsules 400 mg twice daily or cediranib 30 mg daily and olaparib capsules 200 mg twice daily until disease progression. Results: In this updated analysis, median PFS remained significantly longer with cediranib/olaparib compared with olaparib alone (16.5 versus 8.2 months, hazard ratio 0.50; P = 0.007). Subset analyses within stratum defined by BRCA status demonstrated statistically significant improvement in PFS (23.7 versus 5.7 months, P = 0.002) and OS (37.8 versus 23.0 months, P = 0.047) in gBRCA wild-type/unknown patients, although OS was not statistically different in the overall study population (44.2 versus 33.3 months, hazard ratio 0.64; P = 0.11). PFS and OS appeared similar between the two arms in gBRCAm patients. The most common CTCAE grade 3/4 adverse events with cediranib/olaparib remained fatigue, diarrhea, and hypertension. Conclusions: Combination cediranib/olaparib significantly extends PFS compared with olaparib alone in relapsed platinum-sensitive ovarian cancer. Subset analyses suggest this margin of benefit is driven by PFS prolongation in patients without gBRCAm. OS was also significantly increased by the cediranib/olaparib combination in this subset of patients. Additional studies of this combination are ongoing and should incorporate analyses based upon BRCA status.