Human Biotransformation of the Nonnucleoside Reverse Transcriptase Inhibitor Rilpivirine and a Cross-Species Metabolism Comparison

Abstract

Rilpivirine is a nonnucleoside reverse transcriptase inhibitor used to treat HIV-1. In the present study, the pathways responsible for the biotransformation of rilpivirine were defined. Using human liver microsomes, the formation of two mono-and two dioxygenated metabolites were detected via ultra high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Mass spectral analysis of the products suggested that these metabolites resulted from oxygenation of the 2,6-dimethylphenyl ring and methyl groups of rilpivirine. Chemical inhibition studies and cDNA-expressed cytochrome P450 (CYP) assays indicated that oxygenations were catalyzed primarily by CYP3A4 and CYP3A5. Glucuronide conjugates of rilpivirine and a monomethylhydroxylated metabolite of rilpivirine were also detected and were found to be formed by UDP-glucuronosyltransferases (UGTs) UGT1A4 and UGT1A1, respectively. All metabolites that were identified in vitro were detectable in vivo. Further, targeted UHPLC-MS/MS-based in vivo metabolomics screening revealed that rilpivirine treatment versus efavirenz treatment may result in differential levels of endogenous metabolites, including tyrosine, homocysteine, and adenosine. Rilpivirine biotransformation was also assessed across species using liver microsomes isolated from a range of mammals, and the metabolite profile identified using human liver microsomes was largely conserved for both oxidative and glucuronide metabolite formation. These studies provide novel insight into the metabolism of rilpivirine and the potential differential effects of rilpivirine-and efavirenz-containing antiretroviral regimens on the endogenous metabolome.benzonitrile, is a more recently developed nonnucleoside reverse transcriptase inhibitor that has been FDA approved for oral administration in combination therapy for the treatment of drug-naive individuals infected with human immunodeficiency virus 1 (HIV-1) (1). RPV is a cyanovinyl diarylpyrimidine and as such has inherent molecular flexibility, allowing for multiple modes of allosteric binding within the hydrophobic binding pocket of the HIV reverse transcriptase; therefore, RPV has a higher genetic barriertoresistancethantheinitiallydevelopednonnucleosidereversetranscriptaseinhibitors,efavirenzandnevirapine(2,3).Inaddition,becauseof its antiviral efficacy, RPV is being developed as an injectable, long-acting formulation for potential use in HIV preexposure prophylaxis (4, 5). ECHO and THRIVE clinical trials, comparing RPV-tenofoviremtricitabine (Complera) treatment to that with efavirenz-tenofoviremtricitabine (Atripla), demonstrated that the RPV coformulation has more potent antiviral activity and fewer adverse side effects than does a daily antiretroviral efavirenz-based regimen. In these studies, the most noted adverse events associated with the efavirenz-containing regimen were psychiatric symptoms and rash; however, the molecular mechanism(s) that underlie the differences in the safety profiles of RPVcontaining versus efavirenz-containing regimens is u...

Population Pharmacokinetics and Pharmacogenetics Analysis of Rilpivirine in HIV-1-Infected Individuals

“…The CYP1A2 gene is reported to be involved in RPV metabolism (8). However, the CYP1A2 gene is highly inducible by many environmental factors, and functional polymorphisms have mostly been described in Asian populations (15).…”

“…We tested 5 genes (CYP3A4, CYP2C19, CYP3A5, UGT1A1, and UGT1A4) involved in RPV metabolism based on the information provided by the manufacturer (1, 2) and the existing literature (8). We selected 6 single nucleotide polymorphisms (SNPs) with a proven functional effect and a minor allelic frequency (MAF) of greater than 0.05 in Caucasians: rs35599367, a marker of loss-of-function (LOF) allele CYP3A4*22; rs776746, a marker of LOF allele CYP3A5*3; rs4244285, a marker of LOF allele CYP2C19*2; rs12248560, a marker of gain-of-function (GOF) allele CYP2C19*17; rs8175347, a marker of LOF allele UGT1A1*28; and rs6755571, a marker of LOF allele UGT1A4*2) (http://www.cypalleles.ki.se/) (20)(21)(22)(23)(24)(25)(26)(27).…”

“…It undergoes oxidative metabolism in the liver that is mainly mediated by CYP3A4 and to a lesser extent by CYP2C19 (1,2). Recently, in vitro observations suggested that UGT1A1 and UGT1A4 are also involved in RPV metabolism (8).…”

Valproic Acid Is a Novel Activator of AMP-Activated Protein Kinase and Decreases Liver Mass, Hepatic Fat Accumulation, and Serum Glucose in Obese Mice

“…Optimal parent mass, product ion transitions, and collision energies were determined for each molecule using synthetic standards. Resolution and sample preparation was performed as previously described (Lade et al, 2013). Table 1 details the compounds analyzed, respective selected reaction monitoring transitions, collision energies, and retention times.…”

Distinct Pharmacodynamic Activity of Rilpivirine in Ectocervical and Colonic Explant Tissue

“…Cytochrome P450 (CYP) isoforms metabolize RPV as well as DPV into similar minor oxidative metabolites (1,32), and UDPglucuronosyltransferases (UGTs) create glucuronide metabolites (32). CYP expression has been documented in vaginal and colonic tissues, and UGT expression was found only in colonic tissue and contributed to the metabolism of topically applied DPV in vivo (33).…”