ASCO 2023: Combination Therapy With Olaparib Plus Pembrolizumab in Biliary Tract Cancers

By: Amanda E. Ruffino, BA
Posted: Friday, June 16, 2023

James O’Bryan, MD, of MedStar Georgetown University Hospital, Washington, DC, and colleagues aimed to evaluate the efficacy of combining the PARP inhibitor olaparib with the anti–PD-1 inhibitor pembrolizumab in the treatment of patients with biliary tract cancers carrying mutations in homologous recombination DNA damage repair (HR-DDR) pathways. Presented at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 4087), their findings indicate the overall response rate did not significantly improve with the combination, but two patients with HR-DDR mutations had a durable response, suggesting further investigation in this area may be warranted.

A total of 14 eligible patients were enrolled between June 2020 and March 2022, and 13 patients were evaluated for efficacy. The median age of the patients was 63 years; they were primarily female (71%) and had metastatic disease (93%). The treatment regimen consisted of oral olaparib (300 mg twice daily) and intravenous pembrolizumab (200 mg every 3 weeks), with patients receiving a mean of 6.5 cycles of therapy.

The primary endpoint of overall response rate was 15.3%, indicating no significant improvement compared with historic controls. However, two patients with HR-DRR mutations (particularly RAD51, ATM, and BRCA2) demonstrated a durable treatment response. One patient achieved a response lasting 8 months, and the other patient continued to exhibit a response at 24 months. The median time to disease progression was 7.7 months (95% confidence interval = 1.2–9.3 months).

Additionally, treatment-related adverse events were reported in most patients (64%). Grade 3 adverse events in five patients (36%) included anemia, diarrhea, and transaminitis. Despite these adverse events, the combination therapy was generally well tolerated, with an acceptable safety profile, according to the study authors.

Disclosure: Dr. O’Bryan reported no conflicts of interest. For full disclosures of the other study authors, visit coi.asco.org.

2023 ASCO Annual Meeting

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