Disposition and metabolism of ¹⁴C-dovitinib (TKI258), an inhibitor of FGFR and VEGFR, after oral administration in patients with advanced solid tumors

Abstract

Purpose

This study investigated the metabolism and excretion of dovitinib (TKI258), a tyrosine kinase inhibitor that inhibits fibroblast, vascular endothelial, and platelet-derived growth factor receptors, in patients with advanced solid tumors.

Methods

Four patients (cohort 1) received a single 500 mg oral dose of ¹⁴C-dovitinib, followed by the collection of blood, urine, and feces for ≤10 days. Radioactivity concentrations were measured by liquid scintillation counting and plasma concentrations of dovitinib by liquid chromatography–tandem mass spectrometry. Both techniques were applied for metabolite profiling and identification. A continuous-dosing extension phase (nonlabeled dovitinib 400 mg daily) was conducted with the 3 patients from cohort 1 and 9 additional patients from cohort 2.

Results

The majority of radioactivity was recovered in feces (mean 61 %; range 52–69 %), as compared with urine (mean 16 %; range 13–21 %). Only 6–19 % of the radioactivity was recovered in feces as unchanged dovitinib, suggesting high oral absorption. ¹⁴C-dovitinib was eliminated predominantly via oxidative metabolism, with prominent primary biotransformations including hydroxylation on the fluorobenzyl ring and N-oxidation and carbon oxidation on the methylpiperazine moiety. Dovitinib was the most prominent radioactive component in plasma. The high apparent volume of distribution (2,160 L) may indicate that dovitinib distributes extensively to tissues. Adverse events were predominantly mild to moderate, and most common events included nausea, vomiting, constipation, diarrhea, and fatigue.

Conclusions

Dovitinib was well absorbed, extensively distributed, and eliminated mainly by oxidative metabolism, followed by excretion, predominantly in feces. The adverse events were as expected for this class of drug.