Role of low-frequency HIV-1 variants in failure of nevirapine-containing antiviral therapy in women previously exposed to single-dose nevirapine

Abstract

In the OCTANE/A5208 study of initial antiretroviral therapy (ART) in women exposed to single-dose nevirapine (sdNVP) ≥6 mo earlier, the primary endpoint (virological failure or death) was significantly more frequent in the NVP-containing treatment arm than in the lopinavir/ritonavir-containing treatment arm. Detection of NVP resistance in plasma virus at study entry by standard population genotype was strongly associated with the primary endpoint in the NVP arm, but two-thirds of endpoints occurred in women without NVP resistance. We hypothesized that low-frequency NVP-resistant mutants, missed by population genotype, explained excess failure in the NVP treatment arm. Plasma samples from 232 participants were analyzed by allele-specific PCR at study entry to quantify NVP-resistant mutants down to 0.1% for 103N and 190A and to 0.3% for 181C. Of 201 women without NVP resistance by population genotype, 70 (35%) had NVP-resistant mutants detected by allele-specific PCR. Among these 70 women, primary endpoints occurred in 12 (32%) of 38 women in the NVP arm vs. 3 (9%) of 32 in the lopinavir/ritonavir-containing arm (hazard ratio = 3.84). The occurrence of a primary endpoint in the NVP arm was significantly associated with the presence of K103N or Y181C NVP-resistant mutations at frequencies >1%. The risk for a study endpoint associated with NVP-resistant mutant levels did not decrease with time. Therefore, among women with prior exposure to sdNVP, low-frequency NVP-resistant mutants were associated with increased risk for failure of NVP-containing ART. The implications for choosing initial ART for sdNVP-exposed women are discussed.mother-to-child transmission | nonnucleoside reverse transcriptase inhibitors S ingle-dose nevirapine (sdNVP) administered at the onset of labor to pregnant HIV-infected women can reduce the risk for mother-to-child transmission (MTCT) of HIV by ∼50% (1-3), but NVP-resistant HIV-1 mutants emerge in the majority of women who have received sdNVP alone (4, 5). These mutants most commonly encode K103N, Y181C, or G190A mutations in HIV-1 RT, conferring resistance to NVP and efavirenz. With the use of sensitive drug resistance assays, such as allele-specific PCR (ASP), resistant mutants can be detected in the majority of women after NVP exposure and can persist for years (6, 7).In resource-limited settings, NVP in combination with lamivudine (3TC) and zidovudine (AZT) or tenofovir disoproxil fumarate (TDF) is recommended as the standard of care for first-line antiretroviral therapy (ART) (8). This recommendation is potentially problematic for women who have been previously exposed to sdNVP (9-11). The A5208/OCTANE trials were designed to compare protease inhibitor-based therapy using lopinavir/ritonavir (LPV/r) with NVP-based therapy in ART-naive women with or without prior sdNVP. A5208 trial 1, which will be the focus of this report, showed that LPV/r + TDF and emtricitabine (FTC) was superior to NVP + TDF/FTC (P = 0.001) for initial therapy of women with prior sdNVP ≥6 mo earlier and a CD4 cell...

Low-Frequency Drug Resistance in HIV-Infected Ugandans on Antiretroviral Treatment Is Associated with Regimen Failure

“…Preexisting dominant NVP mutations were a major risk factor for failure. Subsequent studies also showed that a high risk of treatment failure was also observed in women who had received single-dose NVP and had NVP-resistant HIV-1 variants at low frequency (49,71).…”

“…Unfortunately, there have been few research studies examining the impact of low-frequency drug-resistant HIV-1 variants in treatment-experienced patients due to the current success of cART in HICs; very low failure rates; and, so far, limited availability of clinical tests aimed at quantifying low-frequency HIV-1 variants (24,73). The OCTANE/A5208 study by the AIDS Clinical Trial Group provides our best indication that low-frequency mutations can impact treatment outcomes (49,71,74,75). Women who had previously received a single-dose of NVP to prevent mother-to-child transmission had a 30% rate of treatment failure if randomized to receive an NVP-containing regimen versus a Ͻ10% failure rate with a ritonavir-boosted lopinavir (LPV/r)-containing regimen of FTC plus TDF.…”

“…However, physicians typically switch to a salvage treatment regimen if treatment failure continues and HIV drug resistance was not detected by the Sanger-based test on the previous visit sample. Based on (i) the strong correlations between the detection of low-frequency HIV drug resistance mutations and continued treatment failure (here) and (ii) previous studies in Ugandan women showing that lowfrequency NVP mutations led to failure of NNRTI-containing cART (49,71), our ethics committee decided against a study in which the same cART was continued when low-frequency HIV drug resistance mutations were detected at Ͼ5%. More importantly, we have also adopted DeepGen as the preferred HIV drug resistance genotyping test in the JCRC.…”

Validation of an Oligonucleotide Ligation Assay for Quantification of Human Immunodeficiency Virus Type 1 Drug-Resistant Mutants by Use of Massively Parallel Sequencing

“…HIV genotyping is routinely performed by Sanger sequencing of plasma HIV RNA; however, this technology is too costly and technically demanding to implement in most low-resource laboratories and clinics. Furthermore, the sensitivity of consensus sequencing is limited for minor variants constituting Ͻ25% of the viral population (7,8), although low-frequency HIV drug resistance mutations, particularly involving resistance to nonnucleoside reverse transcriptase (RT) inhibitors (NNRTIs), have been associated with increased risks of virological failure with first-line ART (9)(10)(11)(12)(13)(14)(15). Therefore, sensitive and affordable assays are needed to monitor HIV drug resistance as part of global HIV treatment programs.…”

HIV Drug Resistance in Mothers and Infants Following Use of Antiretrovirals to Prevent Mother-to-Child Transmission

“…Among those with NVP resistance, 73 % in the NVP group compared to only 6 % in the LPV/rt group died or had virologic failure (p = 0.006). Analysis of the OCTANE participants revealed that at the time of starting ART with an NNRTI regimen, those women with either K103N or Y181C at a concentration >1 % of the plasma HIV population by AS-PCR testing were at increased risk of virologic failure or death (HR 2.93, 95 % CI 1.27-6.75) (Boltz et al 2011). This finding supports the assertion that minority variant resistant virus can impact the response to ART and highlights the potential impact of sensitive resistance assays for women who used sdNVP.…”