Olaparib Combined With Abiraterone for Metastatic Castration-Resistant Prostate Cancer
Posted: Tuesday, July 31, 2018
Based upon a randomized phase II study presented at the 2018 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 5003), olaparib combined with abiraterone was of benefit in patients with metastatic castration-resistant prostate cancer, improving median radiologic progression-free survival over the current standard of case, abiraterone monotherapy. Although safety data were less favorable for the combination therapy, no detriment to quality of life was reported.
In Study 08, 142 patients previously treated with docetaxel were randomized to receive olaparib or placebo (comparator therapy) plus abiraterone and treated until disease progression. Overall, a statistically significant increase in radiologic progression-free survival was seen with the combination therapy versus abiraterone alone (median of 13.8 months vs. 8.2 months). The median overall survival was 22.7 versus 20.9 months in the combination versus comparator arms, respectively.
As for adverse events, 54% of patients receiving the combination therapy versus 28% of patients receiving abiraterone monotherapy had grade ≥ 3 adverse events; in addition, 34% versus 18% reported serious adverse events, including more cardiovascular toxicity with the combination therapy.
As noted by lead author Noel Clarke, MBBS, FRCS, ChM, Director of Manchester University’s Genitourinary Cancer Research Group, Manchester, UK, in an ASCO press release, “This is the first time we have seen an improvement with the use of a PARP inhibitor in combination with abiraterone in patients with metastatic castration-resistant prostate cancer, and this effect may be independent of [homologous recombination repair] status.”