Background: PARP inhibitors and anti-angiogenics are clinically active in recurrent ovarian cancer (OvCa). Preclinical studies suggest these agents can synergize, and a phase 1 study showed that the combination of cediranib (ced) and olaparib (olap) is well-tolerated. We therefore compared the activity of olap alone (Olap) to combined ced and olap (Ced/Olap) in treatment of recurrent platinum-sensitive (plat-sens) high-grade serous (HGS) or BRCA-related OvCa (NCT 01116648). Methods: Patients (pts) across 9 centers were randomized 1:1 in this Ph 2 open label study to Olap (olap 400 mg capsules BID) or Ced/Olap (olap 200 mg capsules BID; ced 30 mg daily), stratified by BRCA status and prior anti-angiogenic therapy. Eligibility included pts with recurrent plat-sens HGS or BRCA-related OvCa. Pts had measurable disease by RECIST 1.1, PS 0 or 1, and the ability to take POs. No prior anti-angiogenics in the recurrent setting or prior PARP inhibitor was allowed. Progression-free survival (PFS) was defined as time from randomization to radiographic progression or death. With a target N=90 pts, the study was powered to detect a hazard ratio (HR) of 1.75 (median PFS 6 vs 10.5 mo). Results: Pts were enrolled from Oct 2011 to Jun 2013: 46 to Olap, 44 to Ced/Olap. 48 pts were known BRCA carriers (25 Olap; 23 Ced/Olap). At a planned interim analysis the DSMB recommended release of data. As of Jan 7, 2014, 41 pts had a PFS event. Median PFS was 9.0 mos for Olap and 17.7 mos for Ced/Olap (HR 2.9, 95% CI 1.5-5.6, p = 0.001). There were 2 complete responses (CR) and 21 partial responses (PR) in pts on Olap (56% objective response rate, ORR) and 3 CRs and 33 PRs in pts on Ced/Olap (84% ORR, p = 0.008). The overall rate of Gr3/4 toxicity was higher for pts on Ced/Olap (70%) than on Olap (7%). Differentially occurring toxicities included fatigue (27% Ced/Olap vs 7% Olap), diarrhea (23% vs 0%), and hypertension (39% vs 0%). Updated efficacy and exploratory subgroup analyses will be presented. Conclusions: Combined Ced/Olap significantly extended PFS and ORR compared to Olap in plat-sens OvCa. Further studies of this oral combination in plat-sens OvCa are warranted. Clinical trial information: NCT01116648.