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.

JUNG-YUN LEE Department of Obstetrics and Gynecology, Institute of Women's Life Medical Science, Yonsei University College of Medicine, Seoul, South Korea info_outline JUNG-YUN LEE, Jae-Weon Kim, Sang Wun Kim, Hee Seung Kim, Se Ik Kim, Myong Cheol Lim, Chel Hun Choi, Natalie Ngoi, David Shao Peng Tan, Yoo Na Kim, Byoung-Gie Kim

Authors JUNG-YUN LEE Department of Obstetrics and Gynecology, Institute of Women's Life Medical Science, Yonsei University College of Medicine, Seoul, South Korea info_outline JUNG-YUN LEE, Jae-Weon Kim, Sang Wun Kim, Hee Seung Kim, Se Ik Kim, Myong Cheol Lim, Chel Hun Choi, Natalie Ngoi, David Shao Peng Tan, Yoo Na Kim, Byoung-Gie Kim Organizations Department of Obstetrics and Gynecology, Institute of Women's Life Medical Science, Yonsei University College of Medicine, Seoul, South Korea, Seoul National University, Seoul, South Korea, Yonsei University College of Medicine, Seoul, South Korea, Seoul National University Hospital, Seoul, South Korea, Seoul National University College of Medicine, Seoul, South Korea, National Cancer Center, Goyang-Si, Gyeonggi-Do, South Korea, Samsung Medical Center, Seoul, South Korea, Department of Investigational Cancer Therapeutics, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, National University Cancer Institute, Singapore and Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore, Yonsei University Health System, Seoul, South Korea, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea Abstract Disclosures Research Funding No funding received 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.