KEY TAKEAWAYS
- Olaparib aimed to demonstrate significant improvement in progression-free survival compared to chemotherapy treatment in patients with gBRCAm, HER2-negative metastatic breast cancer, according to the Phase III OlympiAD study.
- In the final pre-specified analysis, olaparib did not show a statistically significant improvement in overall survival compared to chemotherapy treatment of physician’s choice, with median overall survival of 19.3 months for olaparib and 17.1 months for TPC.
- With extended follow-up, a post-hoc analysis demonstrated an additional 25.7 months of overall survival data, with olaparib continuing to show a non-statistically significant improvement in overall survival compared to TPC.
- Olaparib showed a significant improvement in overall survival, with median overall survival of 22.6 months for olaparib compared to 14.7 months for TPC, and three-year survival of 40.8% for olaparib compared to 12.8% for TPC.
- No new serious adverse events related to olaparib were observed, supporting its safety profile in this patient population.
Patients with germline BRCA-mutated (gBRCAm), HER2-negative metastatic breast cancer (mBC) saw a substantial extension in progression-free survival when treated with olaparib compared to chemotherapeutic treatment of physician’s choice (TPC) in the Phase III OlympiAD research. Overall median survival (OS) for those treated with olaparib was 19.3 months, while that for those treated with TPC was 17.1 months (P = 0.513) in the final pre-specified analysis (64 percent of patients were adults). In addition, there was an increase in post-hoc follow-up of 25.7 months compared to what had been reported for OS before.
Metastatic breast cancer patients with gBRCAm who had previously been treated with at least two courses of chemotherapy were randomly assigned to receive either olaparib (300 mg bid) or TPC. The stratified log-rank test (overall population) and the Cox proportional hazards model were used to evaluate OS at 6-month intervals throughout the prolonged follow-up period (pre-specified subgroups).
Median overall survival (OS) for olaparib was 19.3 months, and for TPC it was 17.1 months (hazard ratio [HR] 0.89, 95% confidence interval [CI] 0.67-1.18); median follow-up was 18.9 and 15.5 months, respectively, in the full cohort of 302 patients (76.8% mature). With olaparib, the three-year survival rate was 27.9%, while with TPC, it was only 21.2%.
While comparing olaparib to TPC, 8.8% of patients completed the study’s treatment period of >3 years, while 0% completed the same period with TPC. The median overall survival (OS) for patients with 1st-line metastatic breast cancer treated with olaparib was 40.8% vs. to 12.8% for those treated with TPC (median OS: 22.6 months vs. 14.7 months; HR: 0.55, 95% CI: 0.33-0.95). There were no newly reported major adverse effects from olaparib use.
Previous OlympiAD analyses corroborated the findings of OS. These results lend credence to the idea that olaparib may provide a substantial improvement in long-term survival, especially in 1L mBC.
Source: https://www.ejcancer.com/article/S0959-8049(23)00080-1/fulltext
Clinical trial: https://clinicaltrials.gov/ct2/show/NCT02000622
Robson, M.E., Im, S.-A., Senkus, E., Xu, B., Domchek, S.M., Masuda, N., Delaloge, S., Tung, N., Armstrong, Anne., Dymond, M., Fielding, A., Allen, A. and Conte, P. (2023). OlympiAD extended follow-up for overall survival and safety: olaparib versus chemotherapy treatment of physician’s choice in patients with a germline BRCA mutation and HER2-negative metastatic breast cancer. European Journal of Cancer. doi:https://doi.org/10.1016/j.ejca.2023.01.031.
