A long-acting injectable formulation of rilpivirine (RPV), a non-nucleoside reverse transcriptase inhibitor, is currently under investigation for use in human immunodeficiency virus (HIV) maintenance therapy. We previously characterized RPV metabolism after oral dosing and identified seven metabolites: four metabolites resulting from mono- or dioxygenation of the 2,6-dimethylphenyl ring itself or either of the two methyl groups located on that ring, one N-linked RPV glucuronide conjugate, and two O-linked RPV glucuronides produced via glucuronidation of mono- and dihydroxymethyl metabolites. However, as is true for most drugs, the metabolism of RPV after injection has yet to be reported. The phase II clinical trial HPTN 076 enrolled 136 HIV-uninfected women and investigated the safety and acceptability of long-acting injectable RPV for use in HIV pre-exposure prophylaxis. Through the analysis of plasma samples from 80 of these participants in the active product arm of the study, we were able to detect 2 metabolites after intramuscular injection of long-acting RPV, 2-hydroxymethyl-RPV, and RPV N-glucuronide. Of the total of 80 individuals, 72 participants exhibited detectable levels of 2-hydroxymethyl-RPV in plasma samples whereas RPV N-glucuronide was detectable in plasma samples of 78 participants. In addition, RPV N-glucuronide was detectable in rectal fluid, cervicovaginal fluid, and vaginal tissue. To investigate potential genetic variation in genes encoding enzymes relevant to RPV metabolism, we isolated genomic DNA and performed next-generation sequencing of CYP3A4, CYP3A5, UGT1A1 and UGT1A4. From these analyses, four missense variants were detected for CYP3A4 whereas one missense variant and one frameshift variant were detected for CYP3A5. A total of eight missense variants of UGT1A4 were detected, whereas two variants were detected for UGT1A1; however, these variants did not appear to account for the observed interindividual variability in metabolite levels. These findings provide insight into the metabolism of long-acting RPV and contribute to an overall understanding of metabolism after oral dosing versus injection.

中文翻译：

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肌内注射后长效利匹韦林的代谢：HIV 预防试验网络研究 076 (HPTN 076)

一种非核苷类逆转录酶抑制剂利匹韦林 (RPV) 的长效注射制剂目前正在研究用于人类免疫缺陷病毒 (HIV) 维持治疗。我们之前对口服给药后的 RPV 代谢进行了表征，并确定了七种代谢物：四种代谢物是由 2,6-二甲基苯基环本身或位于该环上的两个甲基中的一个或一个 N-连接的 RPV 葡糖苷酸结合物产生的。以及通过单羟甲基和二羟甲基代谢物的葡糖醛酸化产生的两种 O-连接的 RPV 葡糖苷酸。然而，与大多数药物一样，注射后 RPV 的代谢尚未见报道。II 期临床试验 HPTN 076 招募了 136 名未感染 HIV 的女性，并调查了长效可注射 RPV 用于 HIV 暴露前预防的安全性和可接受性。通过分析来自该研究的活性产品部门的 80 名参与者的血浆样本，我们能够在肌肉注射长效 RPV、2-羟甲基-RPV 和 RPV N-葡糖苷酸后检测到 2 种代谢物。在总共 80 人中，72 名参与者在血浆样本中表现出可检测水平的 2-羟甲基-RPV，而在 78 名参与者的血浆样本中可检测到 RPV N-葡糖苷酸。此外，在直肠液、宫颈阴道液和阴道组织中可检测到 RPV N-葡糖苷酸。为了研究编码与 RPV 代谢相关的酶的基因的潜在遗传变异，CYP3A4、CYP3A5、UGT1A1和UGT1A4。从这些分析中，检测到CYP3A4的四个错义变体，而CYP3A5检测到一个错义变体和一个移码变体。共检测到 8 个UGT1A4错义变体，而UGT1A1检测到 2 个变体；然而，这些变异似乎并未解释观察到的代谢物水平的个体间变异性。这些发现提供了对长效 RPV 代谢的深入了解，并有助于全面了解口服给药与注射后的代谢。