Metformin pharmacokinetics in presence of letrozole + abemaciclib

This entry describes a clinical drug-drug interaction (DDI) scenario rather than a single biological target molecule. Metformin is a biguanide antihyperglycemic agent that is primarily eliminated unchanged in the urine through active secretion mediated by specific renal transporters, including Organic Cation Transporter 2 (OCT2) and Multidrug and Toxin Extrusion proteins 1 and 2-K (MATE1 and MATE2-K) (Source: PubMed, PMID 21574692). Abemaciclib is a selective inhibitor of cyclin-dependent kinases 4 and 6 (CDK4/6) used in the treatment of breast cancer; it and its major metabolites are known inhibitors of these renal transporters (Source: FDA Verzenio Prescribing Information). Clinical studies have shown that co-administration of abemaciclib can increase metformin systemic exposure (AUC) by approximately 37% and peak concentration (Cmax) by 22% by reducing its renal clearance. Letrozole, an aromatase inhibitor often used in combination with abemaciclib, does not typically have a direct impact on metformin transporters but is part of the therapeutic regimen being evaluated in this pharmacokinetic context. Monitoring for metformin-associated adverse events, such as gastrointestinal distress or lactic acidosis, is recommended when these drugs are used concurrently. This interaction highlights the importance of transporter-mediated pathways in determining drug safety and efficacy in oncology patients with comorbid conditions.

Other names

Metformin-Abemaciclib interactionMetformin-Letrozole-Abemaciclib DDIAbemaciclib effect on Metformin PK

Inhibition of renal transporters MATE1, MATE2-K, and OCT2 by abemaciclib and its metabolites, which decreases the active tubular secretion of metformin and increases its plasma concentration.