palbociclib + modafinil

Palbociclib is an orally available, small molecule inhibitor of cyclin-dependent kinases 4 and 6 (CDK4/6), developed primarily for the treatment of hormone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer. It works by inhibiting CDK4/6, which are key regulators of the cell cycle G1-S transition, thereby preventing cell proliferation in susceptible tumor cells[1][2][4]. Modafinil is a wakefulness-promoting agent used to treat conditions such as narcolepsy and other sleep disorders; it acts primarily as a moderate inducer of CYP3A enzymes. When coadministered, modafinil can decrease plasma concentrations and exposure (AUC) of palbociclib due to its CYP3A induction properties[3][4][5]. This combination is not a fixed-dose pharmaceutical product but refers to concurrent use.