EUROPA & 1NSPIRE study: Real-world data in advanced ovarian cancer

Prof Dr Christine Gennigens, medical oncologist at the CHU Liège discussed two real-world studies evaluating outcomes in patients with advanced ovarian cancer receiving first-line maintenance therapy with niraparib. To contextualise these findings, a brief overview of the pivotal PRIMA/ENGOT-OV26 trial is warranted. 

In this trial, patients with newly diagnosed advanced ovarian cancer were randomly assigned in a 2:1 ratio to niraparib or placebo once daily after a response to platinum-based chemotherapy. With a median follow-up of approximately 64–70 months, the primary endpoint of PFS was met, demonstrating a significant benefit in favour of niraparib in both the HRD–positive and overall populations. However, OS, a key secondary endpoint did not differ significantly between treatment arms, likely influenced by a higher rate of subsequent PARP inhibitor use in the placebo group.

The EUROPA study sought to evaluate the potential impact of excluding patients with FIGO stage III disease and no residual disease from the PRIMA trial. EUROPA was a retrospective, multicenter study conducted in France, Germany, and Italy and included patients who initiated niraparib maintenance therapy between 2018 and 2023. A total of 186 patients were analysed, approximately 25% of whom had stage III disease with no residual disease after primary surgery. The study demonstrated superior clinical outcomes in patients with stage III no residual disease, including longer real-world time to treatment discontinuation, extended time to next treatment or death, and improved PFS. These findings support the hypothesis that the efficacy of niraparib observed in the PRIMA may have been underestimated due to the exclusion of patients with inherently more favourable prognostic features.

The 1NSPIRE study was a retrospective, multicenter real-world analysis conducted in the United States that included patients who initiated niraparib between 2020 and 2023. This study enrolled 218 patients, more than 82% of whom achieved a complete or partial response following first-line platinum-based chemotherapy. The median follow-up was 23 months, and 75% of patients received a starting dose of 200 mg of niraparib. The longest median real-world time to next treatment and PFS were observed in patients with HRD-positive tumours. No statistically significant differences in OS were observed between the analysed subgroups. 

In conclusion, these real-world analyses suggest that niraparib maintenance therapy may be associated with more favourable outcomes in routine clinical practice than those observed in the PRIMA trial, potentially due to broader patient inclusion criteria. Nevertheless, cautious interpretation is required given the retrospective nature of the analyses, potential selection bias, and the inherent limitations of cross-trial comparisons.