Distinct renal adverse event profiles among CDK4/6 inhibitors: a comparative pharmacovigilance analysis.

Objective: Renal adverse events associated with cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors have gained increasing attention in clinical practice. However, comparative real-world data regarding renal safety profiles among individual CDK4/6 inhibitors remain limited. This study aimed to characterize renal adverse event reporting associated with abemaciclib, palbociclib, and ribociclib and compare disproportionality signals among these agents using the U.S. Food and Drug Administration Adverse Event Reporting System (FAERS). Methods: A retrospective pharmacovigilance analysis was conducted using FAERS reports submitted between January 2014 and March 2026. Renal adverse events were identified using Medical Dictionary for Regulatory Activities (MedDRA) Preferred Terms within the Renal and Urinary Disorders System Organ Class. Reporting odds ratios (RORs) with 95% confidence intervals (CIs) were calculated to evaluate disproportionality signals for selected renal and electrolyte adverse events. Results: Following deduplication, 14,193 reports associated with abemaciclib, 91,359 with palbociclib, and 29,488 with ribociclib were identified. Renal adverse events were reported in 898, 2,636, and 1,826 reports, respectively. Acute kidney injury was more frequently reported with abemaciclib (35.7%) and ribociclib (19.7%) than with palbociclib (12.4%) (p < 0.001). Renal impairment/failure was the most commonly reported grouped renal adverse event category. Abemaciclib demonstrated the highest reporting odds for acute kidney injury (ROR 4.06, 95% CI 3.53-4.67), followed by ribociclib (ROR 1.94, 95% CI 1.69-2.22), whereas ribociclib showed the strongest disproportionality signals for decreased glomerular filtration rate, hypocalcemia, creatinine increased, hyponatremia, and hypokalemia. Overall, 65.6% of reports were serious and hospitalization occurred in 32.5% of cases. Conclusion: This large-scale pharmacovigilance analysis identified substantial differences in renal adverse event reporting patterns among CDK4/6 inhibitors. Abemaciclib was more frequently associated with acute kidney injury and adverse events suggestive of intrinsic renal injury, whereas ribociclib demonstrated stronger signals for laboratory indicators of renal dysfunction and electrolyte abnormalities. Although spontaneous reporting data cannot establish causality or estimate incidence, these findings suggest heterogeneous renal adverse event profiles among CDK4/6 inhibitors and support careful renal monitoring during treatment.