Maintenance olaparib therapy improved overall survival (OS) versus placebo in a phase 3 study of patients with platinum-sensitive, relapsed ovarian cancer, according to final analysis and 5-year follow-up data for the SOLO2 trial that were presented at the virtual 2020 ASCO Annual Meeting.

“The PARP inhibitor olaparib is approved in numerous countries as maintenance therapy for patients with platinum-sensitive relapsed ovarian cancer regardless of BRCA mutation status and for patients with BRCA-mutated newly diagnosed ovarian cancer,” explained Andres Poveda, MD, Initia Oncology, Valencia, Spain, during his presentation.

Patients with platinum-sensitive relapsed, ovarian cancer and BRCA mutation who had received ≥2 lines of previous chemotherapy were randomized to receive maintenance olaparib therapy 300mg twice daily (n = 196) or placebo (n = 99).

The primary analysis showed that maintenance olaparib yielded a clinically significant improvement in progression-free survival compared with placebo, as well as acceptable tolerability.

The median follow-up, as of final data cutoff (February 2020), was 65 months, and OS was a secondary endpoint.

In the final analysis, a long-term treatment benefit was seen with olaparib versus placebo. At 5 years, 42.1% of patients in the olaparib arm were alive versus 33.2% in the placebo arm. Furthermore, 28.3% of patients in the olaparib arm were alive and had not received additional treatment compared with 12.8% in the placebo arm; in addition, 38.4% of patients in the placebo arm crossed over to receiving a PARP inhibitor.

The median OS was 51.7 months with olaparib versus 38.8 months with placebo, and, according to Dr Poveda, despite the long duration of treatment, only 18% of patients discontinued therapy due to adverse events.

“In the final analysis of SOLO2, maintenance olaparib provided an unprecedented improvement of 12.9 months in median OS [versus] placebo. This is the first study with olaparib tablets, and the first since Study 19, to provide long-term follow-up and final OS data in patients with platinum-sensitive relapsed ovarian cancer and a BRCA mutation,” the investigators concluded. —Kaitlyn Manasterski

Poveda A, Floquet A, Ledermann JA, et al. Final overall survival (OS) results from SOLO2/ENGOT-ov21: A phase III trial assessing maintenance olaparib in patients (pts) with platinum-sensitive, relapsed ovarian cancer and a BRCA mutation. Presented at: the 2020 ASCO Annual Meeting; May 29-31, 2020. Abstract 6002.