Olaparib: a review of its use as maintenance therapy in patients with ovarian cancer.

Olaparib (Lynparza™) is a first-in-class, orally-active, small molecule, poly (ADP-ribose) polymerase inhibitor that induces synthetic lethality in homozygous BRCA-deficient cells. In the EU, the capsule formulation of olaparib is indicated as monotherapy for the maintenance treatment of adult patients with platinum-sensitive, relapsed, BRCA-mutated (germline and/or somatic), high-grade serous epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in complete or partial response to platinum-based chemotherapy. This approval was based on the results of study 19, a randomized phase II trial in 265 patients with platinum-sensitive, relapsed, high-grade serous ovarian cancer (HGSOC) who had received two or more platinum-based regimens and who had a partial or complete response to their most recent platinum-based regimen. Study 19 met its primary endpoint by demonstrating a significant improvement in progression-free survival in patients receiving olaparib compared with those receiving placebo. Moreover, a preplanned retrospective analysis identified those patients with a BRCA mutation (who comprised one-half of the overall study population) as being the subgroup that derived the greatest clinical benefit from olaparib. Single-agent olaparib was generally well tolerated, with the majority of adverse events being of mild to moderate severity and not requiring interruption of treatment. Fatigue, anaemia and neutropenia were the most frequently reported severe (grade ≥3) adverse events. An as yet unapproved tablet formulation of olaparib that has a lower pill burden than the capsule formulation is currently being investigated in phase III clinical studies.