Dr. Antonio González-Martín from the Cancer Center Clínica Universidad de Navarra in Spain presented the results of the phase III PRIMA/ENGOT-OV26/GOG-3012 study (abstract number LBA29) at the 2024 ESMO Congress. For patients with advanced ovarian cancer with homologous recombination deficiency (HRd), the possibility of progression-free survival after treatment with niraparib is twice that of placebo, although the study did not report long-term overall survival (OS) benefit. Oncology Frontier invited Dr.Antonio González-Martín on site to analyze the clinical significance of this research finding.

Oncology Frontier: ESMO 2024 announced the final overall survival of the PRIMA/ENGOT-ov26/GOG-3012 study. What is your evaluation of the new data on first-line maintenance treatment with niraparib?

Dr. González-Martín: Hi. My name is Antonio González-Martín. I am the Principal Investigator of the PRIMA study, which is also named ENGOT-OV26/GOG-3012. I had the privilege and honor of presenting at this edition of the ESMO Congress in Barcelona in 2024 the final analysis, including long-term outcomes and the overall survival data, from this important study.

To summarize briefly, in the PRIMA study we randomized patients with high-grade serous or endometrioid ovarian cancer who had responded to platinum to niraparib or placebo  as maintenance therapy. The primary endpoint of the study was progression-free survival, and the overall survival was a key secondary endpoint. Five years ago, at this conference in this city, I had the honor of presenting the first results of the primary analysis, demonstrating the benefit of niraparib as maintenance therapy for patients who had responded to first-line platinum across the different biomarker subgroups. Yesterday, I presented the long-term data.

I would like to give you three important messages. The first is the long-term progression-free survival of our study confirmed the benefit of the addition of niraparib as maintenance therapy in the first-line for the homologous recombination deficiency (HRD) population. Actually, at five years, the rate of patients alive without progression in the niraparib arm is double compared to those patients treated with placebo. It was 35% with niraparib, and 15% with placebo. So the first message is long-term sustained benefit with niraparib in the HRD population. Secondly, we haven’t demonstrated a benefit in overall survival, which was the key secondary endpoint. That could be explained for two main reasons. The first is the long post-progression survival. The median post-progression survival in the PRIMA study was extremely high. The rate of patients alive at five years was much higher than expected. The second reason is because of the crossover therapy. In PRIMA, a three-fold probability of receiving PARP inhibitors was observed in the placebo arm, and in particular for the BRCA-mutated patients, it was 60%. And my final message is that long-term safety with niraparib is consistent with the well-known safety profile of niraparib. As you probably also know, the use of the individualized dose is associated with a lower rate of hematological toxicity. So, taking all this information together, we consider that the PRIMA study is consistent and has demonstrated that niraparib as maintenance after first-line platinum-based chemotherapy provides benefit for our patients in the HRD population. Thank you very much for your attention.