ASTRO 2020: Olaparib Plus Radiotherapy for Advanced Triple-Negative Breast Cancer
Posted: Tuesday, November 10, 2020
In a single-institution phase I study of the PARP inhibitor olaparib plus concurrent radiotherapy to the breast wall and regional lymph nodes in patients with inflammatory, locoregionally advanced, or metastatic triple-negative breast cancer, a team of French investigators attempted to determine the maximally tolerated dose of olaparib. Youlia Kirova, MD, of Institut Curie, Paris, France, and colleagues identified 200 mg twice daily as the target dose of olaparib in the RADIOPARP trial and suggested further follow-up is necessary to assess late adverse events. Their findings were presented during the virtual edition of the 2020 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract 50).
A total of 24 patients were enrolled between September 2017 and November 2019; they all had a performance status of 0 or 1. All of the patients received a full course of radiotherapy plus olaparib twice daily: four were given a dose of 50 mg, eight received 100 mg, seven were given 150 mg, and five received 200 mg. The median patient age was 46 years, and the majority of patients (58%) had clinical T2 disease.
The investigators observed no dose-limiting toxicities. However, two patients did develop acute grade 3 dermatitis related to radiotherapy, but no grade 4 adverse events related to radiotherapy were noted. As for toxicity related to olaparib, most of the adverse events were grade 1 or 2. Lymphopenia was the sole grade 3 or 4 hematologic side effect reported (in 11 patients).
Disclosure: The study authors reported no conflicts of interest.