Gilead Sciences, Inc., Foster City, California, USA.
Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.
Antimicrob Agents Chemother. 2018 Apr 26;62(5). doi: 10.1128/AAC.02587-17. Print 2018 May.
Sofosbuvir and ribavirin exert their anti-hepatitis C virus (anti-HCV) activity following metabolic activation in the liver. However, intrahepatic concentrations of the pharmacologically active nucleotide metabolites in humans are poorly characterized due to the inaccessibility of tissue and technical challenges with measuring nucleotide levels. A clinical study assessing the efficacy of sofosbuvir and ribavirin administered prior to liver transplantation to prevent HCV recurrence provided a unique opportunity to quantify nucleotide concentrations in human liver. We analyzed nucleotides using high-performance liquid chromatography coupled to tandem mass spectrometry in liver tissue from 30 HCV-infected patients with hepatocellular carcinoma who were administered sofosbuvir (400 mg/day) and ribavirin (1,000 to 1,200 mg/day) for 3 to 52 weeks prior to liver transplantation. Median total hepatic metabolite concentrations (the sum of nucleoside and mono-, di-, and triphosphates) were 77.1 μM for sofosbuvir and 361 μM for ribavirin in patients on therapy at the time of transplantation. Ribavirin and sofosbuvir efficiently loaded the liver, with total hepatic metabolite concentrations exceeding maximal levels in plasma by approximately 30-fold. Ribavirin metabolite levels suggest that its monophosphate is in great excess of its inhibition constant for IMP dehydrogenase and that its triphosphate is approaching the binding constant for incorporation by the HCV NS5B RNA-dependent RNA polymerase. In accordance with the potent antiviral activity of sofosbuvir, these results demonstrate that the liver triphosphate levels achieved following sofosbuvir administration greatly exceed the inhibition constant for HCV NS5B. In conclusion, this study expands the quantitative understanding of the pharmacology of sofosbuvir and ribavirin by establishing efficient hepatic delivery in the clinic. (This study has been registered at ClinicalTrials.gov under identifier NCT01559844.).
索非布韦和利巴韦林在肝脏中经代谢激活后发挥抗丙型肝炎病毒（抗-HCV）活性。然而，由于组织不可及以及核苷酸水平测量的技术挑战，人体内具有药理活性的核苷酸代谢物的肝内浓度特征描述较差。一项评估索非布韦和利巴韦林在肝移植前给药以预防 HCV 复发的疗效的临床研究为定量分析人肝内核苷酸浓度提供了一个独特的机会。我们使用高效液相色谱-串联质谱法分析了 30 例丙型肝炎病毒感染合并肝细胞癌患者肝组织中的核苷酸，这些患者在肝移植前 3 至 52 周接受了索非布韦（400mg/天）和利巴韦林（1000-1200mg/天）治疗。在移植时接受治疗的患者的肝内总代谢物浓度（核苷和单、二、三磷酸盐的总和）中位数分别为索非布韦 77.1μM 和利巴韦林 361μM。利巴韦林和索非布韦有效地向肝脏加载，肝内总代谢物浓度超过血浆中最大浓度约 30 倍。利巴韦林代谢物水平表明，其单磷酸盐远远超过其对 IMP 脱氢酶的抑制常数，其三磷酸盐接近 HCV NS5B RNA 依赖性 RNA 聚合酶掺入的结合常数。与索非布韦的强大抗病毒活性一致，这些结果表明，索非布韦给药后达到的肝三磷酸盐水平大大超过 HCV NS5B 的抑制常数。总之，这项研究通过在临床上建立有效的肝内递送，扩展了对索非布韦和利巴韦林药理学的定量理解。（本研究已在 ClinicalTrials.gov 注册，标识符为 NCT01559844。）。
