Characterization of Genotypic and Phenotypic Changes in HIV-1-Infected Patients with Virologic Failure on an Etravirine-Containing Regimen in the DUET-1 and DUET-2 Clinical Studies

Resistance to the nonnucleoside reverse transcriptase inhibitors etravirine and rilpivirine (RPV) is conferred by the E138K mutation in human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT).Clinical trials of RPV administered with lamivudine or emtricitabine showed the emergence of E138K together with M184I, which confers lamivudine and emtricitabine resistance in most patients with virologic failure. To understand why M184I was favored over M184V, we determined the drug susceptibility, infectivity, relative fitness, and reverse transcriptase activity of HIV-1 carrying E138K/M184I or E138K/M184V mutations. Whereas the replication capacity (RC) of the single mutants was reduced compared to that of the wild type (WT), the RC of the two double mutants was comparable to that of the WT in the absence of drug. The RC of the E138K/M184I mutant in the presence of etravirine was significantly greater than that of the E138K and E138K/M184V mutants; the RC of the double mutants was greater than that of the M184I or M184V mutant. Fitness profiles and growth competition experiments showed that the E138K/M184I mutant had a significant replicative advantage over the E138K/M184V mutant in the presence of etravirine and lamivudine. The virion-associated RT activity of the E138K, M184I, or M184V virus was significantly reduced compared to that of the WT, whereas the RT activity of the E138K/M184I virus was significantly greater than that of the WT or E138K/M184V virus. These results suggest that the E138K and M184I/V mutations are mutually compensatory and may explain the frequent occurrence of E138K/M184I after the virologic failure of rilpivirine-, lamivudine-, and emtricitabine-containing regimens.Nonnucleoside reverse transcriptase inhibitors (NNRTIs) are key components of combination antiretroviral therapy. Etravirine (ETV; formerly TMC125) and rilpivirine (RPV; formerly TMC278) are potent next-generation NNRTIs that retain activity against efavirenz (EFV)-resistant viruses carrying the K103N mutation in human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) (1, 3); both are diarylpyrimidine (DAPY) compounds. The E138K mutation, which emerges both in vitro and in vivo, confers resistance to ETV and RPV (2,3,22,23). Although in vitro passage experiments suggested that resistance to ETV and RPV emerges more slowly than resistance to first-generation NNRTIs (e.g., nevirapine [NVP] or EFV) (3, 25), this finding has not been confirmed in clinical trials, which show the emergence of ETV and RPV resistance at the time of virologic failure in most patients treated with these drugs (17, 18).Most antiretroviral regimens include the cytosine analogs lamivudine (3TC) or emtricitabine (FTC) administered as fixed-dose combinations together with zidovudine (ZDV) or abacavir (ABC) in the case of ZDV/3TC and ABC/3TC or with tenofovir (TDF) in the case of TDF/FTC. Resistance to 3TC and FTC is conferred by a valine or isoleucine substitution for the methionine normally found at position 184, which lies in the ...

Section: Resistance To the Nonnucleoside Reverse Transcriptase Inhibimentioning

confidence: 99%

Interaction of Reverse Transcriptase (RT) Mutations Conferring Resistance to Lamivudine and Etravirine: Effects on Fitness and RT Activity of Human Immunodeficiency Virus Type 1

Hu¹,

Kuritzkes²

2011

“…The phase III DUET clinical trials on the use of ETR in treatment-experienced HIV-1-infected patients showed that substitutions at position V179 were most common among treatment failures, followed by mutations at position E138, among which the E138G and E138Q mutations, but not the E138K mutation, were frequently observed (46). Recently, phase III clinical trials (ECHO and THRIVE) on the use of the combination of RPV-tenofovir disoproxil fumarate (TDF)-emtricitabine (FTC) in drug-naïve patients showed that the most frequent mutations to emerge among virological failures were the mutations E138K and M184I, which are responsible for resistance to FTC and RPV, respectively (34).…”

mentioning

confidence: 99%

Subunit-Selective Mutational Analysis and Tissue Culture Evaluations of the Interactions of the E138K and M184I Mutations in HIV-1 Reverse Transcriptase

Oliveira

Quashie

et al. 2012

The emergence of HIV-1 drug resistance remains a major obstacle in antiviral therapy. M184I/V and E138K are signature mutations of clinical relevance in HIV-1 reverse transcriptase (RT) for the nucleoside reverse transcriptase inhibitors (NRTIs) lamivudine (3TC) and emtricitabine (FTC) and the second-generation (new) nonnucleoside reverse transcriptase inhibitor (NNRTI) rilpivirine (RPV), respectively, and the E138K mutation has also been shown to be selected by etravirine in cell culture. The E138K mutation was recently shown to compensate for the low enzyme processivity and viral fitness associated with the M184I/V mutations through enhanced deoxynucleoside triphosphate (dNTP) usage, while the M184I/V mutations compensated for defects in polymerization rates associated with the E138K mutations under conditions of high dNTP concentrations. The M184I mutation was also shown to enhance resistance to RPV and ETR when present together with the E138K mutation. These mutual compensatory effects might also enhance transmission rates of viruses containing these two mutations. Therefore, we performed tissue culture studies to investigate the evolutionary dynamics of these viruses. Through experiments in which E138K-containing viruses were selected with 3TC-FTC and in which M184I/V viruses were selected with ETR, we demonstrated that ETR was able to select for the E138K mutation in viruses containing the M184I/V mutations and that the M184I/V mutations consistently emerged when E138K viruses were selected with 3TC-FTC. We also performed biochemical subunit-selective mutational analyses to investigate the impact of the E138K mutation on RT function and interactions with the M184I mutation. We now show that the E138K mutation decreased rates of polymerization, impaired RNase H activity, and conferred ETR resistance through the p51 subunit of RT, while an enhancement of dNTP usage as a result of the simultaneous presence of both mutations E138K and M184I occurred via both subunits.

“…In patients failing ETR-containing regimens, Y181C was shown to commonly occur (26,42). HIV-1 containing Y181C alone showed moderate-level resistance to ETR (8,41).…”

mentioning

confidence: 99%

“…The E138K mutation was shown to be the first mutation selected by ETR in cell culture passage experiments (5). Viruses containing E138K display moderate resistance to ETR (5,41,47), and E138K has been reported to emerge in HIV-1-infected patients who have failed an ETR-containing regimen (41,42). Thus, E138K has the potential to be an important ETR resistance mutation, particu-larly in the case of wild-type (WT) viruses (6).…”

mentioning

confidence: 99%

Molecular Mechanism of Antagonism between the Y181C and E138K Mutations in HIV-1 Reverse Transcriptase

Oliveira

Asahchop

et al. 2012

Etravirine (ETR) is an expanded-spectrum nonnucleoside reverse transcriptase inhibitor (NNRTI) approved for use as an antiretroviral agent in treatment-experienced patients. Y181C and E138K in HIV-1 RT are among 20 different drug resistance mutations associated with ETR. However, E138K can be consistently selected by ETR when wild-type viruses but not viruses containing Y181C are grown in tissue culture. This study was carried out to evaluate any possible mechanisms that might explain antagonism between the Y181C and E138K mutations. Accordingly, we performed tissue culture studies to investigate the evolutionary dynamics of E138K in both a wild-type (WT) and a Y181C background. We also generated recombinant enzymes containing Y181C and E138K alone or in combination in order to study enzyme processivity, rates of processive DNA synthesis, enzyme kinetics, and susceptibility to ETR. We now show that the presence of the Y181C mutation prevented the emergence of E138K in cell culture and that the simultaneous presence of E138K and Y181C impaired each of enzyme activity, processivity, rate of processive DNA synthesis, and deoxynucleoside triphosphate (dNTP) affinity. The addition of E138K to Y181C also decreased the level of resistance to ETR compared to that obtained with Y181C alone.