Fluorouracil systemic exposure when capecitabine is coadministered with sunitinib

The phrase 'Fluorouracil systemic exposure when capecitabine is coadministered with sunitinib' refers to a pharmacokinetic (PK) observation or clinical study parameter rather than a biological target such as a protein or receptor. Capecitabine is an oral fluoropyrimidine carbamate that acts as a prodrug of 5-fluorouracil (5-FU), an antimetabolite used in cancer therapy (Source: FDA Label for Xeloda). Sunitinib is a small-molecule inhibitor of multiple receptor tyrosine kinases (RTKs), including VEGFR and PDGFR, used primarily for renal cell carcinoma and imatinib-resistant GIST (Source: FDA Label for Sutent). Research into their coadministration typically focuses on whether sunitinib alters the metabolic conversion of capecitabine to 5-FU or affects the clearance of 5-FU, which could lead to increased systemic toxicity or altered efficacy. Clinical data generally suggest that sunitinib does not have a clinically significant effect on the pharmacokinetics of capecitabine or its metabolites, including 5-FU (Source: Robert et al., Clinical Cancer Research, 2009). This interaction is monitored because both drugs share overlapping toxicity profiles, such as hand-foot syndrome and gastrointestinal distress. Understanding this exposure is critical for the safe development of combination regimens in oncology to ensure that the therapeutic index of 5-FU is maintained. Therefore, this entry represents a drug-drug interaction (DDI) profile rather than a therapeutic target molecule.

Other names

Capecitabine-sunitinib drug-drug interaction5-FU exposure with sunitinibPharmacokinetics of capecitabine and sunitinib combination

This entry describes a pharmacokinetic interaction rather than a biological target. Capecitabine is an oral prodrug converted to 5-fluorouracil (5-FU) via a three-step enzymatic pathway involving carboxylesterase, cytidine deaminase, and thymidine phosphorylase. Sunitinib is a multi-targeted receptor tyrosine kinase inhibitor (RTKI) that inhibits VEGFR, PDGFR, and KIT.