medwireNews: Progression-free survival (PFS) is significantly improved with the use of maintenance olaparib in women with newly diagnosed FIGO stage III or IV ovarian cancer and a BRCA1/2 mutation, shows the placebo-controlled SOLO1 trial.
Among the participants, all of whom had either a germline or somatic BRCA mutation and a complete or partial response to platinum-based chemotherapy, the risk for disease progression or death was a significant 70% lower in the 260 patients who were randomly assigned to receive the PARP inhibitor at a dose of 300 mg twice daily as maintenance therapy than for their 131 counterparts who received placebo.
As reported at the ESMO 2018 Congress and published in The New England Journal of Medicine, median PFS was unreached for the olaparib group and was 13.8 months for the placebo group after a median follow-up of 40.7 and 41.2 months, respectively. The corresponding 3-year PFS rates were 60% and 27%.
Speaking at a press conference in Munich, Germany, lead investigator Kathleen Moore (University of Oklahoma, Oklahoma City, USA) described the PFS improvement with olaparib as “unprecedented,” and noted that the gain was maintained throughout follow-up, even though olaparib was stopped at 2 years for most patients, “indicating an apparent enduring treatment benefit.”
She added: “We believe that the SOLO1 data really promise a change in the standard of care for women with advanced ovarian cancer who harbor a BRCA mutation and we hope that this will be available to patients relatively soon.”
Other endpoints also improved significantly with olaparib; the risk for second disease progression or death, for instance, was halved in the olaparib versus placebo group, while the time to first subsequent therapy or death was longer, at a median of 51.8 and 15.1 months, respectively.
Moore highlighted that the adverse event (AE) profile of olaparib in SOLO1 “was very much in line with every other study evaluating olaparib in every other line of therapy,” with “very manageable low-grade AEs.”
She said that the tolerability was also demonstrated “by the fact that only 11.5% of patients discontinued olaparib due to AEs and over 70% of patients who started olaparib maintained their starting dose throughout their participation in the trial.”
Commentator Jonathan Ledermann, from University College London in the UK, told the press that the PFS data are “very robust” as the analysis was conducted when all participants had been followed up for at least 3 years.
“Of course we are going to have to wait until the overall survival data mature,” he said, but “there is a real hope that this treatment will perhaps lead to an increase in the cure rate, which will be reflected by a reduction in the first relapse rate.”
Ledermann continued: “We’ll have to wait longer for that but there’s no doubt that this is a big step forward for BRCA-mutated ovarian cancer.”
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