Phase I dose-escalation studies of roniciclib, a pan-cyclin-dependent kinase inhibitor, in advanced malignancies

BACKGROUND: To evaluate safety, pharmacokinetics, and maximum tolerated dose of roniciclib in patients with advanced malignancies, with dose expansion to evaluate clinical benefit at the recommended phase II dose (RP2D). METHODS: Two phase I dose-escalation studies evaluated two roniciclib dosing schedules: 3 days on/4 days off or 4 weeks on/2 weeks off. The expansion phase included patients with small-cell lung cancer (SCLC), ovarian cancer, or tumour mutations involving the CDK signalling pathway. RESULTS: Ten patients were evaluable in the 4 weeks on/2 weeks off schedule (terminated following limited tolerability) and 47 in the 3 days on/4 days off schedule dose-escalation cohorts. On the 3 days on/4 days off schedule, RP2D was 5 mg twice daily in solid tumours (n=40); undetermined in lymphoid malignancies (n=7). Common roniciclib-related adverse events included nausea (76.6%), fatigue (65.8%), diarrhoea (63.1%), and vomiting (57.7%). Roniciclib demonstrated rapid absorption and dose-proportional increase in exposure. One partial response (1.0%) was observed. In RP2D expansion cohorts, the disease control rate (DCR) was 40.9% for patients with ovarian cancer (n=25), 17.4% for patients with SCLC (n=33), and 33.3% for patients with CDK-related tumour mutations (n=6). CONCLUSIONS: Roniciclib demonstrated an acceptable safety profile and moderate DCR in 3 days on/4 days off schedule.