Therapeutic drug monitoring in breast cancer therapy - LC-MS/MS method for quantification of the CDK4/6 inhibitors abemaciclib, palbociclib, ribociclib, and major metabolites abemaciclib M20 and M2 in human serum.

The cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors palbociclib, ribociclib, and abemaciclib were approved by the U.S. Food and Drug Administration (FDA) and European Medicine Agency for the treatment of breast cancer between 2015 and 2018.

Isotope dilution LC-MS/MS quantification of the cystic fibrosis transmembrane conductance regulator (CFTR) modulators ivacaftor, lumacaftor, tezacaftor, elexacaftor, and their major metabolites in human serum.

Objectives: Cystic fibrosis (CF) transmembrane conductance regulator (CFTR) modulators have revolutionized the therapeutic landscape in CF treatment. These vital drugs are extensively metabolized via CYP3A, so caution must be exercised in multimodal CF therapy because of the risk of adverse drug interactions. Our goal was to develop a highly sensitive assay for the purpose of therapeutic drug monitoring (TDM) in diagnostic laboratories.