Syntheses of [2H3,15N], [14C]Nexavar™ and its labeled metabolites

Transarterial embolization with sorafenib in animal livers: a pharmacokinetics study

PURPOSE

To assess the safety and feasibility of the targeted delivery of the antiangiogenic drug sorafenib to the liver using transarterial chemoembolization methodology as a novel approach to hepatocellular carcinoma (HCC) therapy.

MATERIALS AND METHODS

Seven healthy New Zealand white rabbits were used in the study. After placement of a catheter in the common hepatic artery, six rabbits were treated with chemoembolization of sorafenib in iodized oil (Lipiodol) (sorafenib dose 0.1 mg/kg), and one rabbit received Lipiodol only. Liquid chromatography tandem mass spectrometry was used to measure the concentration of sorafenib in the peripheral blood and liver tissue 24 hours and 72 hours after treatment. Histochemical staining of the liver sections and biochemical measurements were performed.

RESULTS

The administration of sorafenib in Lipiodol emulsions by transarterial chemoembolization resulted in sorafenib concentrations of 794 ng/g ± 240 and 64 ng/g ± 15 in the liver tissue 24 hours and 72 hours after treatment. The average liver-to-serum ratios 24 hours and 72 hours after treatment were approximately 14 and 22. The histochemical staining of the liver tissue sections and aspartate aminotransferase, alanine aminotransferase, γ-glutamyltransferase and total bilirubin concentrations indicated no significant liver damage.

CONCLUSIONS

Transarterial chemoembolization with sorafenib in Lipiodol is an effective methodology for the localized delivery of this drug to the liver and has possible practical implications in therapeutic interventions for the treatment of hepatocellular carcinoma.

Anti-proliferative actions of N'-desmethylsorafenib in human breast cancer cells

The multi-kinase inhibitor sorafenib is used for the treatment of renal and hepatic carcinomas and is undergoing evaluation for treatment of breast cancer in combination with other agents. Cytochrome P450 (CYP) 3A4 converts sorafenib to multiple metabolites that have been detected in patient plasma. However, recent clinical findings suggest that combination therapy may elicit inhibitory pharmacokinetic interactions involving sorafenib that increase toxicity. While sorafenib N-oxide is an active metabolite, information on the anti-tumor actions of other metabolites is unavailable. The present study evaluated the actions of sorafenib and its five major metabolites in human breast cancer cell lines. All agents, with the exception of N'-hydroxymethylsorafenib N-oxide, decreased ATP formation in four breast cancer cell lines (MDA-MB-231, MDA-MB-468, MCF-7 and T-47D). Prolonged treatment of MDA-MB-231 cells with N'-desmethylsorafenib, N'-desmethylsorafenib N-oxide and sorafenib (10 μM, 72 h) produced small increases in caspase-3 activity to 128-139% of control. Sorafenib and its metabolites, again with the exception of N'-hydroxymethylsorafenib N-oxide, impaired MEK/ERK signaling in MDA-MB-231 cells and modulated the expression of cyclin D1 and myeloid cell leukemia sequence-1, which regulate cell viability. When coadministered with doxorubicin (0.5 or 1 μM), sorafenib and N'-desmethylsorafenib (25 μM) produced greater effects on ATP production than either treatment alone. Thus, it emerges that, by targeting the MEK/ERK pathway, multiple sorafenib metabolites may contribute to the actions of sorafenib in breast cancer. Because N'-desmethylsorafenib is not extensively metabolized and does not inhibit major hepatic CYPs, this metabolite may have a lower propensity to precipitate pharmacokinetic drug interactions than sorafenib.