Interim analysis from a phase II study of olaparib maintenance with pembrolizumab and bevacizumab in BRCA non-mutated patients with platinum-sensitive recurrent ovarian cancer: APGOT-ov4/ OPEB-01.

Abstract

e17579 Background: The optimal treatment of BRCA wild-type patients with platinum-sensitive recurrent (PSR) ovarian cancer remains controversial. This single arm phase 2 study (OPEB-01) evaluated a triple combination regimen with olaparib, bevacizumab, and pembrolizumab as 2nd-line maintenance treatment in BRCA non-mutated, PSR ovarian cancer. Methods: Women with PSR ovarian cancer who had a partial or complete response to their most recent platinum-based regimen were eligible. Patients received olaparib 300mg PO bid daily, bevacizumab 15mg/kg IV q3w, and pembrolizumab 200mg IV q3w until progressive disease or unacceptable toxicity. The primary endpoint of the study was 6-month PFS rate. A simon 2-stage design was utilized. Target accrual was 22 patients in the first stage; 13 or more patients with non-progressive disease at 6 months was required to proceed to second stage. Results: 22 patients were enrolled at the first stage. Median age was 60 years old and most of the patients (90.9%) had high-grade serous carcinoma. Secondary cytoreductive surgery was performed in 6 (27.3%) patients. The objective response rate (ORR) was 68.2% and the disease control rate (DCR) was 90.9%. At the time of data analysis (data cutoff Jan 19 2022), 20 (90.9%) had non-progressive disease at 6 months. No grade 4 adverse events were reported and no treatment related adverse events leading to treatment discontinuation was observed. Additional correlative data regarding homologous recombination deficiency and PD-L1 will be presented at the meeting. Conclusions: OPEB-01 is the first trial to suggest the potential benefit of triple combination maintenance in BRCA wild-type patients. These combinations showed a manageable safety profile. Accrual is ongoing in the second stage. Clinical trial information: NCT4361370.