Olaparib Maintenance Therapy in Patients With Platinum-Sensitive Relapsed Serous Ovarian Cancer: A Preplanned Retrospective Analysis of Outcomes by BRCA Status in a Randomised Phase 2 Trial

Lancet Oncol. 2014 Jul;15(8):852-61. doi: 10.1016/S1470-2045(14)70228-1. Epub 2014 May 31.

Abstract

Background: Maintenance monotherapy with the PARP inhibitor olaparib significantly prolonged progression-free survival (PFS) versus placebo in patients with platinum-sensitive recurrent serous ovarian cancer. We aimed to explore the hypothesis that olaparib is most likely to benefit patients with a BRCA mutation.

Methods: We present data from the second interim analysis of overall survival and a retrospective, preplanned analysis of data by BRCA mutation status from our randomised, double-blind, phase 2 study that assessed maintenance treatment with olaparib 400 mg twice daily (capsules) versus placebo in patients with platinum-sensitive recurrent serous ovarian cancer who had received two or more platinum-based regimens and who had a partial or complete response to their most recent platinum-based regimen. Randomisation was by an interactive voice response system, stratified by time to progression on penultimate platinum-based regimen, response to the most recent platinum-based regimen before randomisation, and ethnic descent. The primary endpoint was PFS, analysed for the overall population and by BRCA status. This study is registered with ClinicalTrials.gov, number NCT00753545.

Findings: Between Aug 28, 2008, and Feb 9, 2010, 136 patients were assigned to olaparib and 129 to placebo. BRCA status was known for 131 (96%) patients in the olaparib group versus 123 (95%) in the placebo group, of whom 74 (56%) versus 62 (50%) had a deleterious or suspected deleterious germline or tumour BRCA mutation. Of patients with a BRCA mutation, median PFS was significantly longer in the olaparib group than in the placebo group (11·2 months [95% CI 8·3-not calculable] vs 4·3 months [3·0-5·4]; HR 0·18 [0·10-0·31]; p<0·0001); similar findings were noted for patients with wild-type BRCA, although the difference between groups was lower (7·4 months [5·5-10·3] vs 5·5 months [3·7-5·6]; HR 0·54 [0·34-0·85]; p=0·0075). At the second interim analysis of overall survival (58% maturity), overall survival did not significantly differ between the groups (HR 0·88 [95% CI 0·64-1·21]; p=0·44); similar findings were noted for patients with mutated BRCA (HR 0·73 [0·45-1·17]; p=0·19) and wild-type BRCA (HR 0·99 [0·63-1·55]; p=0·96). The most common grade 3 or worse adverse events in the olaparib group were fatigue (in ten [7%] patients in the olaparib group vs four [3%] in the placebo group) and anaemia (seven [5%] vs one [<1%]). Serious adverse events were reported in 25 (18%) patients who received olaparib and 11 (9%) who received placebo. Tolerability was similar in patients with mutated BRCA and the overall population.

Interpretation: These results support the hypothesis that patients with platinum-sensitive recurrent serous ovarian cancer with a BRCA mutation have the greatest likelihood of benefiting from olaparib treatment.

Funding: AstraZeneca.

Publication types

  • Clinical Trial, Phase II
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Anemia / chemically induced
  • Antineoplastic Agents / adverse effects
  • Antineoplastic Agents / therapeutic use*
  • Disease-Free Survival
  • Fatigue / chemically induced
  • Female
  • Genes, BRCA1
  • Genes, BRCA2
  • Germ-Line Mutation
  • Humans
  • Maintenance Chemotherapy*
  • Middle Aged
  • Neoplasm Recurrence, Local / drug therapy*
  • Neoplasm Recurrence, Local / genetics
  • Neoplasms, Cystic, Mucinous, and Serous / drug therapy*
  • Neoplasms, Cystic, Mucinous, and Serous / genetics*
  • Ovarian Neoplasms / drug therapy*
  • Ovarian Neoplasms / genetics*
  • Phthalazines / adverse effects
  • Phthalazines / therapeutic use*
  • Piperazines / adverse effects
  • Piperazines / therapeutic use*
  • Poly(ADP-ribose) Polymerase Inhibitors
  • Proportional Hazards Models
  • Retrospective Studies

Substances

  • Antineoplastic Agents
  • Phthalazines
  • Piperazines
  • Poly(ADP-ribose) Polymerase Inhibitors
  • olaparib

Associated data

  • ClinicalTrials.gov/NCT00753545