Metabolism and Pharmacokinetics of Allitinib in Cancer Patients: The Roles of Cytochrome P450s and Epoxide Hydrolase in its Biotransformation
作者:Lishan Lin、Cen Xie、Zhiwei Gao、Xiaoyan Chen、Dafang Zhong
DOI:10.1124/dmd.113.056341
日期:2014.5
Allitinib, a novel irreversible selective inhibitor of the epidermal growth factor receptor (EGFR) 1 and human epidermal receptor 2 (ErbB2), is currently in clinical trials in China for the treatment of solid tumors. It is a structural analog of lapatinib but has an acrylamide side chain. Sixteen metabolites of allitinib were detected by ultra-high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry. The pharmacologically active α , β -unsaturated carbonyl group was the major metabolic site. The metabolic pathways included O -dealkylation, amide hydrolysis, dihydrodiol formation, hydroxylation, and secondary phase 2 conjugation. The metabolite of amide hydrolysis (M6) and 27,28-dihydrodiol allitinib (M10) were the major pharmacologically active metabolites in the circulation. The steady-state exposures to M6 and M10 were 11% and 70% of that of allitinib, respectively. The biotransformation of allitinib was determined using microsomes and recombinant metabolic enzymes. In vitro phenotyping studies demonstrated that multiple cytochrome P450 (P450) isoforms, mainly CYP3A4/5 and CYP1A2, were involved in the metabolism of allitinib. Thiol conjugates (M14 and M16) and dihydrodiol metabolites (M5 and M10) were detected in humans, implying the formation of reactive intermediates. The formation of a glutathione conjugate of allitinib was independent of NADPH and P450 isoforms, but was catalyzed by glutathione-S-transferase. P450 enzymes and epoxide hydrolase were involved in M10 formation. Overall, our study showed that allitinib was metabolized by the O -dealkylation pathway similar to lapatinib, but that amide hydrolysis and the formation of dihydrodiol were the dominant metabolic pathways. The absorbed allitinib was extensively metabolized by multiple enzymes.
艾立替尼 (Allitinib) 是一种新型不可逆选择性表皮生长因子受体 (EGFR) 1 和人表皮受体 2 (ErbB2) 抑制剂,目前在中国处于临床试验阶段,用于治疗实体瘤。它是拉帕替尼的结构类似物,但具有丙烯酰胺侧链。通过超高效液相色谱/四极杆飞行时间质谱法检测到 16 种艾立替尼的代谢物。药理活性 α , β -不饱和羰基是主要的代谢位点。代谢途径包括 O -去烷基化、酰胺水解、二氢二醇形成、羟基化和二期结合。酰胺水解代谢物 (M6) 和 27,28-二氢二醇艾立替尼 (M10) 是循环中主要的药理活性代谢物。M6 和 M10 的稳态暴露量分别是艾立替尼的 11% 和 70%。使用微粒体和重组代谢酶确定了艾立替尼的生物转化。体外表型研究表明,多种细胞色素 P450 (P450) 同工酶,主要是 CYP3A4/5 和 CYP1A2,参与了艾立替尼的代谢。在人体内检测到硫醇结合物 (M14 和 M16) 和二氢二醇代谢物 (M5 和 M10),暗示活性中间体的形成。艾立替尼的谷胱甘肽结合物的形成不依赖于 NADPH 和 P450 同工酶,但受谷胱甘肽-S-转移酶催化。P450 酶和环氧化物水解酶参与了 M10 的形成。总的来说,我们的研究表明艾立替尼通过与拉帕替尼相似的 O -去烷基化途径代谢,但酰胺水解和二氢二醇的形成是主要的代谢途径。吸收的艾立替尼被多种酶广泛代谢。