An exploratory study of PRecision dOsing of moLecular targeted agents based On therapeutic drug monitoriNG

Interventions: 1) PK profiles of regorafenib and its metabolites (M-2/M-5 and M-7/M-8) at week 1, 2, and 3 during the first cycle will be examined. In addition, the subsequent drug concentrations after dose adaptation by taking individual drug concentration and the target trough level (1400 ng/mL) into consideration will be evaluated. 2) PK profile of pazopanib at steady state after start of treatment will be examined. In addition, the subsequent drug concentrations after dose adaptation by taking individual drug concentration and the target trough level (20.5 mcg/mL) into consideration will be evaluated. 3) PK profile of axitinib at steady state after start of treatment will be examined. In addition, the subsequent drug concentrations after dose adaptation by taking individual drug concentration and historical PK data into consideration will be evaluated.
Primary outcome(s): To reveal the clinical benefit of therapeutic drug monitoring (TDM) of molecular targeted agents (regorafenib, pazopanib, and axitinib) in terms of prolonged duration of treatment by determining a tolerable maintenance dose in individual patients, compared with the empirical approach based only on clinical and laboratory findings.
Study Design: Single arm Non-randomized