5-Year Follow-Up of the SOLO1/GOG 3004 Trial of Maintenance Olaparib for Patients with Newly Diagnosed Advanced Ovarian Cancer and a BRCA Mutation

Five-year follow-up results of the SOLO1 trial indicate that 2 years of maintenance olaparib provides sustained progression-free survival benefit in patients with newly diagnosed advanced ovarian cancer harboring BRCA1 and/or BRCA2 mutations, with no emergence of new safety signals.

Primary analysis of the phase 3 SOLO1 trial (NCT01844986; GOG-3004) demonstrated that maintenance olaparib in patients with newly diagnosed advanced ovarian cancer harboring BRCA1 and/or BRCA2 mutations (BRCAm), who responded to first-line platinum-based chemotherapy provides significant progression-free survival (PFS) benefit compared with placebo. The long-term efficacy and safety data of maintenance olaparib after 5 years of follow-up in the SOLO1 trial were published in the October 26, 2021, issue of Lancet Oncology.

The study enrolled patients aged ≥18 years with BRCA-mutated, newly diagnosed, advanced, high-grade serous or endometrioid ovarian cancer, who responded to platinum-based chemotherapy, and had an Eastern Cooperative Oncology Group performance status of 0-1. Eligible patients were randomized (2:1) to receive maintenance olaparib (300 mg twice a day) or placebo for up to 2 years. The primary end point was investigator-assessed PFS. The data cutoff for this analysis was March 5, 2020.

Of the total of 391 patients enrolled in the trial, 260 received olaparib and 131 received placebo, with a median treatment duration of 24.6 months and 13.9 months, respectively. In the intention-to-treat population, median PFS was 56 months in the olaparib cohort (median follow-up of 4.8 years) compared with 14 months in the placebo cohort (median follow-up of 5.0 years).

The safety profile of olaparib was consistent with that previously described. The most frequent grade 3/4 adverse events in the olaparib cohort were anemia (22%) and neutropenia (8%). Serious adverse events occurred in 21% of patients in the olaparib group and 13% in the placebo group. No treatment-related adverse events (that occurred during study treatment or up to 30 days after discontinuation) led to death. The current analysis found no new cases of myelodysplastic syndrome or acute myeloid leukemia.

Long-term safety and efficacy results of the SOLO1 trial demonstrate that 2 years of maintenance olaparib provide sustained PFS benefit. Patients with olaparib-treated, newly diagnosed, advanced ovarian cancer with a BRCAm were progression-free past 4.5 years, with the emergence of no new safety signals.

Source: Banerjee S, Moore KN, Colombo N, et al. Maintenance olaparib for patients with newly diagnosed advanced ovarian cancer and a BRCA mutation (SOLO1/GOG 3004): 5-year follow-up of a randomised, double-blind, placebo-controlled, phase 3 trial. Lancet Oncol. 2021;22:1721-1731.

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