In patients with newly diagnosed advanced ovarian cancer, treatment with rucaparib delays the median time to first and second subsequent anticancer therapy for almost 1 year relative to placebo, according to a study presented at ESMO Gyn 2026.
“Rucaparib prolonged the median time to first and second subsequent therapy for approximately 1 year longer than placebo,” said lead study author Dr Emily Prendergast, Minnesota Oncology, Minneapolis, Minnesota, US.
A total of 538 patients with stage III or IV ovarian cancer who underwent cytoreductive surgery (R0 permitted) and four to eight cycles of first-line platinum-doublet chemotherapy with a response were enrolled in this international, randomized, double-blind, phase III trial. Of these, 427 were randomly assigned to oral rucaparib 600 mg BID and 111 to placebo for up to 2 years.
Investigator-assessed progression-free survival (PFS) was the primary endpoint, while time to first and second subsequent therapies served as exploratory endpoints. Prendergast and her team followed all patients for subsequent anticancer therapy every 12 weeks until death, loss to follow-up, or consent withdrawal. Data cutoff was on 5 May 2025.
A greater proportion of patients in the rucaparib arm (111/427, 26 percent) than those in the placebo arm (15/111, 14 percent) remained in long-term follow-up without receiving any subsequent anticancer therapy. [ESMO Gyn 2026, abstract 112RO]
At least one subsequent therapy was administered to 268 (63 percent) patients in the rucaparib arm and to 86 (78 percent) in the placebo arm (median 2 lines in both arms), while 169 (40 percent) and 58 (52 percent) patients in the respective arms had two or more subsequent therapy.
Notably, patients with advanced ovarian cancer treated with rucaparib showed a longer median time to first (23.6 months; hazard ratio [HR], 0.56, 95 percent confidence interval [CI], 0.44‒0.72) and second (37.9 months; HR, 0.73, 95 percent CI, 0.56‒0.94) subsequent anticancer therapy.
“[The] median time to first subsequent therapy was almost a year longer with rucaparib than placebo,” Prendergast said.
Anticancer therapies
First subsequent therapy was platinum-based in 212 (79 percent) patients in the rucaparib arm and 60 (70 percent) in the placebo arm and was non-platinum in 31 (12 percent) and 23 (27 percent) patients, respectively. PARP inhibitor was administered as subsequent therapy in 14 percent vs 32 percent.
Furthermore, second subsequent therapy was platinum-based in 64 (38 percent) patients in the rucaparib arm and 31 (53 percent) in the placebo arm and was non-platinum in 84 (50 percent) and 20 (35 percent), respectively. PARP inhibitor was 6 percent vs 14 percent.
A previous study has found that the majority (70 percent) of patients with high-grade advanced ovarian cancer relapsed within 3 years. [Ann Oncol 2023;34:833-848]
In the phase III ATHENA-MONO trial, 5-year progression-free rates were higher with rucaparib than with placebo (29 percent vs 16 percent). Moreover, rucaparib delayed the time to first subsequent therapy, while overall survival remains immature, according to Prendergast and colleagues. [Ann Oncol 2026;37:217-228]