Women with newly diagnosed advanced-stage ovarian cancer have a high risk of disease relapse within 3 years of treatment. Now, newly published data from the SOLO1 study demonstrate that progression-free survival (PFS) can be prolonged substantially by using the poly(ADP-ribose) polymerase (PARP) inhibitor olaparib in patients with a germline or somatic BRCA1/2 mutation.

A total of 391 patients were randomly assigned (2:1) to receive either olaparib maintenance therapy or placebo until disease progression, following a complete or partial response to platinum-based therapy. At a median follow-up duration of 40.7 months, 60% of patients receiving olaparib achieved the primary end point of PFS versus 27% of patients in the placebo group (HR 0.30, 95% CI 0.23–0.41; P < 0.001). As part of the trial design, patients with no evidence of disease at 2 years ceased olaparib maintenance therapy at this time point; many of these patients remained free of any detectable disease following olaparib cessation.

In total, 39% of patients in the olaparib group had grade 3–4 adverse events versus 18% in the placebo group. Notable increases in anaemia (22% versus 2%) and neutropenia (9% versus 5%) were reported. The incidence of de novo acute myeloid leukaemia (1%) was consistent with that reported in other trials investigating the effects of PARP inhibitors. In an analysis of health-related quality of life, patients in the placebo group had a greater reduction in Trial Outcome Index Score than those in the olaparib group (estimated between-group difference –3.00 points, 95% CI −4.78 to −1.22), although this difference was not clinically meaningful.

These findings demonstrate that robust improvements in PFS can be obtained using olaparib in the first-line maintenance setting. The authors also note the potential of this approach to be curative in a subset of patients — as observed in previous trials involving patients with relapsed disease; however, longer follow-up monitoring will be required in order to identify this subset.