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Olaparib maintenance therapy in patients with platinum-sensitive relapsed serous ovarian cancer (SOC) and a BRCA mutation (BRCAm).
J Clin Oncol 31, 2013 (suppl; abstr 5505)
Abstracts that were granted an exception in accordance with ASCO's Conflict of Interest Policy are designated with a caret symbol (^).
Background: Previously, we reported that maintenance treatment with the oral PARP inhibitor olaparib (400 mg bid) led to a significant PFS improvement vs placebo in patients (pts) with platinum-sensitive relapsed SOC (Ledermann et al NEJM2012). A preplanned subgroup analysis from this randomized, double-blind Phase II trial (NCT00753545) suggested that olaparib may lead to a greater PFS, and an OS, benefit in pts with a known germline BRCAm (gBRCAm). Since gBRCA wild-type (gBRCAwt) pts may develop somatic tumor (t)BRCAm, efficacy analyses were performed for all pts with BRCAm. Methods: gBRCAm status was determined retrospectively for all consenting pts (n = 166) using blood samples taken before randomization. tBRCAm status was determined from archival tumor samples of 196 pts. We analyzed PFS/OS by gBRCAm and total BRCAm status. Preliminary data are reported. Results: gBRCA status was known for 218/265 pts (gBRCAm, 96; gBRCAwt, 122). Including tBRCAm, 136 pts had a BRCAm (BRCAwt, 116). gBRCAm pts had the greatest PFS benefit with olaparib maintenance vs placebo (median: 11.2 vs 4.1 months [m]; HR, 0.17; 95% CI 0.09-0.32; P<0.001) and a significant QoL improvement, as measured with Trial Outcome Index (OR, 4.08; 95% CI 1.11-19.85; p = 0.03). The PFS benefit was consistent when tBRCAm pts were included (median: 11.2 vs 4.3 m; HR, 0.19; 95% CI 0.11-0.32; p <0.0001). In an interim analysis of OS (58% maturity), a comparison of olaparib vs placebo in the overall population led to a HR of 0.88 (95% CI 0.64-1.21) with medians of 29.8 vs 27.8 m, respectively. Although HRs from the gBRCAm and gBRCAwt subgroups were similar (0.85 and 0.84, respectively), 13/37 gBRCAm placebo pts received a subsequent PARP inhibitor, confounding the OS data in this subgroup. The analysis of all BRCAm pts was less confounded and resulted in an OS HR of 0.74 (95% CI 0.46-1.19; median: 34.9 vs 31.9 m). 19 pts have received olaparib for >3 years. Olaparib tolerability was similar in BRCAm pts and the overall population. Conclusions: Olaparib maintenance treatment led to the greatest clinical benefit in pts with a BRCAm. These compelling data warrant confirmation in phase III trials. Clinical trial information: NCT00753545.
Abstracts by J. A. Ledermann:
Phase II trial of the poly(ADP-ribose) polymerase (PARP) inhibitor AG-014699 in BRCA 1 and 2–mutated, advanced ovarian and/or locally advanced or metastatic breast cancer.
Final results of the EORTC intergroup randomized study 40004 (CLOCC) evaluating the benefit of radiofrequency ablation (RFA) combined with chemotherapy for unresectable colorectal liver metastases (CRC LM).