According to a recent study published in The Lancet Oncology, a 5-year follow-up of patients with newly diagnosed advanced BRCA-mutated ovarian cancer showed that olaparib continues to improve progression-free survival even past treatment completion.
“Patients with newly diagnosed advanced ovarian cancer are at high risk of relapse—approximately 70% of patients will relapse within the first 3 years—and 5-year survival is 30–50%. Once relapse occurs, advanced ovarian cancer is typically incurable; therefore, there is a high unmet need for first-line treatment regimens that can substantially delay recurrence, prolong survival, and ultimately increase the possibility of a cure so that life expectancy for these women can approach that of the age-adjusted general population,” said Susana Banerjee, PhD, researcher at The Royal Marsden NHS Foundation Trust and Institute of Cancer Research in London, UK, and colleagues.
Olaparib is a first-in-class oral poly(ADP-ribose) polymerase (PARP) inhibitor. The SOLO1/GOG 3004 studies were the first to assess the safety and efficacy of a PARP inhibitor as maintenance therapy for patients with newly diagnosed advanced ovarian cancer who also have a BRCA mutation.
SOLO1 was a randomized, double-blind, placebo-controlled, phase 3 trial done across 118 centers in 15 countries. Patients were either given olaparib 300 mg twice daily or a placebo as maintenance monotherapy for up to 2 years. The primary endpoint of the study was progression-free survival.
Between September 2013 and March 2015, 260 patients were randomly assigned to olaparib and 131 patients to placebo. The median treatment duration for the olaparib group was 24.6 months and 13.9 months for the placebo group.
In this post-hoc analysis, 5 years later, median progression-free survival was 56 months in the olaparib group versus 13.8 months in the placebo group.
The most common grade 3 to 4 adverse events included anemia and neutropenia which occurred in 22% and 8% of the olaparib group, respectively. Serious adverse events more broadly occurred in 21% of the olaparib group compared to 13% in the placebo group.
The SOLO1 study looked at the randomized and controlled use of olaparib over 2 years for maintenance therapy in patients with newly diagnosed advanced BRCA-mutant ovarian cancer. In this new post-hoc analysis which looked at a 5-year follow-up of patients, the 2-year olaparib treatment benefit was sustained beyond the end of treatment and has yielded a median progression-free survival past 4.5 years.
This is the only PARP inhibitor in which efficacy has been demonstrated beyond therapy completion.
Disclosures: Some authors declared financial ties to drugmakers. See full study for details.
Funding: This research was funded by AstraZeneca.
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