e13037 Background: Ribociclib is an orally administered CDK4/6 inhibitor used in combination with endocrine therapy (ET) to treat women with hormone receptor-positive (HR+), human epidermal growth factor receptor-2–negative advanced breast cancer (ABC). An integrative assessment was conducted to evaluate the effect of renal function on the pharmacokinetics (PK), efficacy and safety of ribociclib. Methods: To assess the effect of mild and moderate renal impairment, a subgroup analysis was performed to evaluate PK parameters of ribociclib following oral administration of 600 mg QD 3 weeks on/1 week off in two Phase 1/2 and one Phase 3 clinical trials. Steady-state PK exposures in ABC patients at the 600 mg dose was estimated by a population PK model developed based on a pooled dataset from five Phase 1 to 3 trials and were compared by renal function. Efficacy and safety were also analyzed by renal function in a Phase 2 and three Phase 3 trials in ABC patients. The effect of severe renal impairment on ribociclib PK was assessed in a Phase I study in non-cancer subjects following a single oral 400 mg dose. Results: PK analyses in cancer patients showed that both single-dose and steady-state exposure of ribociclib at the 600 mg dose in patients with mild or moderate renal impairment were comparable to patients with normal renal function. Estimated steady-state PK exposure in patients with mild or moderate renal impairment is also comparable to patients with normal renal function. The primary efficacy results of progression free survival (PFS) and the safety profiles were comparable across renal-function cohorts in ABC patients. In non-cancer subjects administered a single oral dose of 400 mg, ribociclib AUCinf and Cmax increased 2.67- and 2.30-fold in subjects with severe renal impairment, respectively, compared to subjects with normal renal function. Conclusions: PK, efficacy and safety of ribociclib are consistent across patients with normal renal function, mild or moderate renal impairment. Hence, no dose adjustment is required in mild or moderate renal impaired patients. Severe renal impaired patients are recommended to have a reduced dose based on PK data in non-cancer subjects.