A combination of niraparib plus anlotinib in patients with platinum-resistant ovarian clear cell carcinoma: Results of a single-arm phase II study (CC-ANNIE study).

e17552 Background: Ovarian clear cell carcinoma (OCCC) is a histological subtype of epithelial ovarian cancer with distinct biological and molecular characteristics. Patients with platinum-resistant OCCC have a poor prognosis and their treatment represents a significant unmet medical need. Studies have suggested potential efficacy of targeting DNA damage response pathways and inhibition of angiogenesis in OCCC. We hypothesised that patients with platinum-resistant OCCC might benefit from a combination of the poly (ADP-ribose) polymerase (PARP) inhibitor niraparib and the anti-angiogenic agent anlotinib. Methods: This was a phase II, single-arm, two-stage study with a Simon’s two-stage optimal design. The trial could continue to stage 2 if ≥1 responses were observed in the first 6 patients. Eligible patients had histologically confirmed OCCC that was platinum resistant, defined as progression within 6 months after their most recent platinum-based chemotherapy. Use of prior bevacizumab was permitted but prior PARP inhibitor or tyrosine kinase inhibitor treatments were not. Patients received niraparib (300 mg/day or 200 mg/day [baseline body weight < 77 kg, platelet count < 150,000/μL], orally) plus anlotinib (10 mg/day, orally, 2 weeks on and 1 week off, every 3 weeks) until disease progression or intolerable toxicity. The primary endpoint was objective response rate (ORR) assessed by investigators according to the RECIST V.1.1. Secondary endpoints included disease control rate (DCR), time to response (TOR), duration of response (DOR), safety and investigator-assessed progression-free survival (PFS) and overall survival (OS). Results: Between January 2022 and August 2022, 6 eligible patients were enrolled and included in the analyses. The median duration of treatment was 9.8 (range, 6.5 to 19.0) weeks. Of the 6 patients, 0 patients (0%) achieved an objective response, resulting in a confirmed ORR of 0%. The DCR was 50% (0 complete response, 0 partial response, 3 stable disease). With a median follow-up time of 7.5 (range, 3.5 to 10.0) months, all patients experienced disease progression, with a median PFS of 12.0 (95% confidence interval [CI], 3.6 to 20.4) weeks. Frequent treatment-related adverse events (AEs) included hypertension (33.3%), thrombocytopenia (33.3%), and hand-foot syndrome (16.6%). Conclusions: The phase 2 CC-ANNIE study did not meet the primary efficacy endpoint. The combination of niraparib and anlotinib did not show activity in patients with platinum-resistant OCCC. Clinical trial information: NCT05130515 .