Novel PARP Inhibitor Combination Shows Promise in Platinum-Resistant Ovarian Cancer
20 December 2025
Results from a Phase Ib dose-escalation trial conducted at the Cancer Institute show that combining niraparib with the ATR inhibitor ceralasertib produces meaningful tumour responses in patients with platinum-resistant ovarian cancer who have exhausted standard treatment options. Among 28 evaluable patients, the objective response rate was 36%, with an additional 29% achieving stable disease.
The combination was particularly effective in patients with BRCA-wild-type tumours that had acquired resistance to prior PARP inhibitor monotherapy — a growing clinical challenge as these agents become standard first-line maintenance therapy. Biomarker analysis revealed that tumours with high replication stress signatures were most likely to respond.
Based on these results, a randomised Phase II trial comparing the combination to physician's choice chemotherapy is now being planned, with the institute serving as the lead coordinating centre.
Why This Matters
Platinum-resistant ovarian cancer has very limited treatment options. This combination approach offers a potential new strategy for patients whose tumours have become resistant to existing PARP inhibitors.