TESARO reports Phase 3 data on niraparib in ovarian cancer, says met endpoint
TESARO announced the presentation of the niraparib Phase 3 ENGOT-OV16/NOVA clinical trial results at the ESMO 2016 Congress. ENGOT-OV16/NOVA is a Phase 3 trial of niraparib that enrolled 553 patients with recurrent ovarian cancer who were in response to their most recent platinum-based chemotherapy. The trial successfully achieved its primary endpoint in both cohorts, demonstrating that niraparib treatment significantly prolonged PFS compared to control in patients who were germline BRCA mutation carriers and in patients who were not germline BRCA mutation carriers. In addition, within the non-gBRCA cohort, niraparib treatment significantly prolonged PFS compared to control for the prospectively defined patient population with tumors deficient in homologous recombination. Specifically, among patients who were germline BRCA mutation carriers, the niraparib arm successfully achieved statistical significance over the control arm for the primary endpoint of PFS, with a hazard ratio of 0.27. The median PFS for patients treated with niraparib was 21.0 months, compared to 5.5 months for control. Niraparib also showed statistical significance for patients in the non-germline BRCA mutant cohort. The niraparib arm successfully achieved statistical significance over the control arm for the primary endpoint of PFS, with a hazard ratio of 0.45. The median PFS for patients treated with niraparib was 9.3 months, compared to 3.9 months for control. For patients who were not germline BRCA mutation carriers but whose tumors were determined to be HRD positive, the niraparib arm successfully achieved statistical significance over the control arm for the primary endpoint of PFS, with a hazard ratio of 0.38. The median PFS for patients with HRD-positive tumors who were treated with niraparib was 12.9 months, compared to 3.8 months for control. Secondary endpoint analyses, including chemotherapy-free interval, time to first subsequent treatment, and PFS 2 were all statistically significant and favored niraparib over control for patients in both the gBRCAmut and non-gBRCAmut cohorts. Patient-reported outcome results from validated survey tools indicated that niraparib-treated patients reported no difference from control in measures associated with quality of life. Data for overall survival are immature, as fewer than 20% of events had occurred at the time of analysis. The most common treatment-emergent grade 3/4 adverse events in the niraparib arm were thrombocytopenia in 33.8%, anemia in 25.3%, and neutropenia in 19.6%. The majority of these hematological laboratory abnormalities occurred within the first three cycles; following dose modifications the incidence of these lab abnormalities decreased and thrombocytopenia and neutropenia were infrequent beyond cycle 3. There were no deaths among patients during study treatment. A high proportion of patients in both treatment groups in both cohorts had received three or more prior lines of chemotherapy.