Related Experiment Video
Updated: Aug 8, 2026

An Affordable HIV-1 Drug Resistance Monitoring Method for Resource Limited Settings
Published on: March 30, 2014
Drug resistance and predicted virologic responses to human immunodeficiency virus type 1 protease inhibitor therapy
J H Condra1, C J Petropoulos, R Ziermann
1Department of Antiviral Research, Merck Research Laboratories, West Point, PA 19486, USA. jon_condra@merck.com
Abstract:
The extent to which human immunodeficiency virus (HIV) type 1 drug resistance compromises therapeutic efficacy is intimately tied to drug potency and exposure. Most HIV-1 protease inhibitors maintain in vivo trough levels above their human serum protein binding-corrected IC(95) values for wild-type HIV-1. However, these troughs are well below corrected IC(95) values for protease inhibitor-resistant viruses from patients experiencing virologic failure of indinavir and/or nelfinavir. This suggests that none of the single protease inhibitors would be effective after many cases of protease inhibitor failure. However, saquinavir, amprenavir, and indinavir blood levels are increased substantially when each is coadministered with ritonavir, with 12-h troughs exceeding corrected wild-type IC(95) by 2-, 7-, and 28-79-fold, respectively. These indinavir and amprenavir troughs exceed IC(95) for most protease inhibitor-resistant viruses tested. This suggests that twice-daily indinavir-ritonavir and, to a lesser extent, amprenavir-ritonavir may be effective for many patients with viruses resistant to protease inhibitors.
Related Concept Videos
Retrovirus Life Cycles
Viral Mutations
Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu
Inhibitors of Viral Protein Synthesis
Antiviral Nucleoside Inhibitors
Inhibitors of Virion Maturation and Assembly

