Justifying Ribociclib Dose in Patients with Advanced Breast Cancer with Renal Impairment Based on PK, Safety, and Efficacy Data: An Innovative Approach Integrating Data from a Dedicated Renal Impairment Study and Oncology Clinical Trials.

BACKGROUND AND OBJECTIVE: Renal impairment is common in patients with cancer and can alter the PK and thus the safety and efficacy of drugs. We assessed the impact of renal impairment during treatment with ribociclib, a cyclin-dependent kinase 4/6 inhibitor, and determined dose recommendations for patients with advanced breast cancer with renal impairment. METHODS: A comprehensive assessment integrating pharmacokinetic, safety, and efficacy data from a phase I dedicated renal impairment study in non-cancer subjects and six phase I-III trials in patients with cancer was performed. RESULTS: Ribociclib showed higher pharmacokinetic exposure in subjects with renal impairment than those with normal renal function following a single 400-mg dose in the dedicated renal impairment study. However, in patient trials, both single-dose and steady­state ribociclib exposure was comparable between patients with cancer with mild/moderate renal impairment and those with normal renal function following the recommended starting dose of 600 mg. Model-predicted steady­state exposure in patients with advanced breast cancer was also similar across the renal function groups. Progression-free survival was similar and safety profiles were generally consistent across the renal cohorts (normal/mild/moderate) in patients with advanced breast cancer, with low-grade and manageable adverse events, demonstrating a positive benefit-risk profile. CONCLUSIONS: From the collective evidence and considering a real-world clinical setting, no dose adjustment is recommended for patients with mild/moderate renal impairment, whereas a reduced dose is recommended for patients with severe renal impairment. This report presented a holistic and innovative strategy to determine dose in patients with renal impairment and demonstrated the effectiveness of integrating the data of both a clinical pharmacology study and patient trials to justify doses in patients with renal impairment. CLINICAL TRIAL REGISTRATION: Clinicaltrials.gov identifiers: NCT02431481, NCT01958021, NCT02422615, NCT02278120, NCT01237236, NCT01898845, NCT01872260.