Low-frequency pre-treatment HIV drug resistance: effects on 2-year outcome of first-line efavirenz-based antiretroviral therapy.

OBJECTIVES: Assess the impact of pre-treatment high-frequency and low-frequency drug-resistant HIV variants on long-term outcomes of first-line efavirenz-based antiretroviral therapy (ART). DESIGN: Prospective observational study. METHODS: Participants' pre-treatment plasma RNA had two sections of HIV pol encoding reverse transcriptase sequenced (Illumina, MiSeq) using unique molecular identifiers to detect wild-type (pre-treatment drug-resistant variants less than 1% of viral quasispecies), low-frequency (1-9%) or high-frequency drug-resistant variants (10-100%). Associations between pre-treatment drug resistance and virologic outcomes over 24 months of efavirenz-based ART were assessed for the number and frequency of mutations by drug class and other resistance parameters. RESULTS: Virologic failure was detected in 30 of 352 (9%) and pre-treatment drug-resistant variants were detected in the viral quasispecies of 31 of 352 (9%) participants prescribed efavirenz-based ART. Survival analyses revealed statistically significant associations between pre-treatment drug resistance at low (P < 0.0001) and high (P < 0.001) frequencies, at oligonucleotide ligation assay (OLA) (P < 0.00001) and non-OLA (P < 0.01) codons, to a single-antiretroviral class (P < 0.00001), and a shorter time to virologic failure of efavirenz-based ART. Regression analyses detected independent effects across resistance categories, including both low-frequency (P < 0.01) and high-frequency (P < 0.001) drug-resistant variants. CONCLUSION: We observed that pre-treatment HIV drug resistance detected at low frequencies increased the risk of virologic failure over 24 months of efavirenz-based ART, but that most failures, regardless of drug-resistant variants' frequencies, were detected within a year of ART initiation. These observations suggest that when efavirenz-based ART is prescribed, screening for pre-treatment drug resistance by an assay capable of detecting low-frequency variants, including OLA, may guide clinicians to prescribe more effective ART.

Assessment of minority frequency pretreatment HIV drug-resistant variants in pregnant women and associations with virologic non-suppression at term.

OBJECTIVE: To assess in ART-naïve pregnant women randomized to efavirenz- versus raltegravir-based ART (IMPAACT P1081) whether pretreatment drug resistance (PDR) with minority frequency variants (<20% of individual's viral quasispecies) affects antiretroviral treatment (ART)-suppression at term. DESIGN: A case-control study design compared PDR minority variants in cases with virologic non-suppression (plasma HIV RNA >200 copies/mL) at delivery to randomly selected ART-suppressed controls. METHODS: HIV pol genotypes were derived from pretreatment plasma specimens by Illumina sequencing. Resistance mutations were assessed using the HIV Stanford Database, and the proportion of cases versus controls with PDR to their ART regimens was compared. RESULTS: PDR was observed in 7 participants (11.3%; 95% CI 4.7, 21.9) and did not differ between 21 cases and 41 controls (4.8% vs 14.6%, p = 0.4061). PDR detected only as minority variants was less common (3.2%; 95% CI 0.2, 11.7) and also did not differ between groups (0% vs. 4.9%; p = 0.5447). Cases' median plasma HIV RNA at delivery was 347c/mL, with most (n = 19/22) showing progressive diminution of viral load but not ≤200c/mL. Among cases with viral rebound (n = 3/22), none had PDR detected. Virologic non-suppression at term was associated with higher plasma HIV RNA at study entry (p<0.0001), a shorter duration of ART prior to delivery (p<0.0001), and randomization to efavirenz- (versus raltegravir-) based ART (p = 0.0085). CONCLUSIONS: We observed a moderate frequency of PDR that did not significantly contribute to virologic non-suppression at term. Rather, higher pretreatment plasma HIV RNA, randomization to efavirenz-based ART, and shorter duration of ART were associated with non-suppression. These findings support early prenatal care engagement of pregnant women and initiation of integrase inhibitor-based ART due to its association with more rapid suppression of plasma RNA levels. Furthermore, because minority variants appeared infrequent in ART-naïve pregnant women and inconsequential to ART-suppression, testing for minority variants may be unwarranted.

Pre-treatment HIV-drug resistance associated with virologic outcome of first-line NNRTI-antiretroviral therapy: A cohort study in Kenya.

BACKGROUND: Pre-treatment HIV-drug-resistance (PDR) to WHO-recommended 1st-line non-nucleoside reverse transcriptase inhibitors (NNRTI)-based antiretroviral treatment (ART) is increasing in low-resource communities. We evaluated the risk of PDR on treatment failure if detected at single or multiple codons, at minority (2-9%) or higher (≥10%) frequencies during efavirenz- vs. nevirapine-ART. METHODS: We conducted a pooled analysis across three cohorts of Kenyans initiating 1st-line NNRTI-ART between 2006 and 2014. Mutations K103N, Y181C, G190A, M184V and K65R were detected by an oligonucleotide ligation assay (OLA) and confirmed by Sanger and next-generation sequencing (NGS). PDR was defined as detection of any mutation by OLA when confirmed by NGS. Treatment failure, defined as plasma HIV RNA ≥400 copies/mL at month-12 of ART, was compared by PDR genotypes. FINDINGS: PDR was detected in 59/1231 (4·8%) participants. Compared to wild-type genotypes, PDR in participants prescribed nevirapine-ART was associated with increased treatment failure [PDR 69·2% (27/39) vs. wild-type 10·4% (70/674); p = 0·0001], whether detected as minority [66·7% (4/6)] or higher [69·7% (23/33)] frequencies in an individual's HIV quasispecies (p = 0·002 and p < 0·0001, respectively), or mutations at single [50·0% (12/24)] or multiple [100·0% (15/15)] codons (p < 0·0001). During efavirenz-ART, PDR was also associated with increased virologic failure [PDR 25·0% (5/20) vs. wild-type 5·0% (25/498); p = 0·005], but only if detected at multiple drug-resistant codons [50·0% (3/6); p = 0·003] or high frequencies PDR [33·3% (5/15); p = 0·001]. INTERPRETATION: The risk that PDR confers for treatment failure varies by number of mutant codons and their frequency in the quasispecies, with a lower risk for efavirenz- compared to nevirapine-based regimens. PDR detection and management could extend the effective use of efavirenz-ART in low-resource settings. FUNDING: NIH, PEPFAR.

Evaluation of the management of pretreatment HIV drug resistance by oligonucleotide ligation assay: a randomised controlled trial.

BACKGROUND: Although experts have recommended testing for pretreatment drug resistance (PDR) before antiretroviral therapy (ART) initiation, there is little evidence to support its implementation. We aimed to establish whether an inexpensive point mutation assay can improve virological suppression by identifying PDR to guide drug selection for ART in a lower-middle income country. METHODS: Investigators did an open-label, randomised controlled trial at three HIV treatment sites in Kenya: two in Nairobi and one in rural Maseno. Individuals (aged ≥2 years) were eligible to participate if they were confirmed HIV-seropositive, qualified for first-line ART, planned to reside in the area for more than 1 year, and provided informed consent. We randomly assigned participants (1:1) to either PDR testing by oligonucleotide ligation assay (OLA) to guide selection of ART or to standard of care, which did not include OLA testing. The OLA-guided therapy group had pre-ART peripheral blood mononuclear cells evaluated for drug resistance to non-nucleoside reverse transcriptase inhibitor (NNRTI) at codons Lys103Asn, Tyr181Cys, Gly190Ala, and to lamivudine at Met184Val, and when at least one drug-resistant codon was detected in a participant's pre-ART specimen, clinicians were directed to prescribe protease inhibitor-based second-line ART. Those without detected resistance and those who were randomised to standard of care received NNRTI-based first-line ART. The primary outcome was plasma HIV-1 RNA of at least 400 copies per mL at 4, 8, or 12 months after ART initiation, which defined virological failure, assessed in all participants who received treatment (data were censored for those lost-to-follow-up or who died). The study has been completed and is registered with ClinicalTrials.gov, NCT01898754. FINDINGS: We screened 1198 participants between May 28, 2013, and Nov 4, 2014, of whom 991 (83%) were enrolled (492 received OLA and 495 received standard of care; four did not begin treatment). 93 participants (prevalence 9·4%) had PDR (95% CI 7·7-11·4). 34 (8·5%) of 400 participants in the OLA group had virological failure at month 12 of ART (95% CI 6·0-11·7) compared with 39 (9·7%) of 402 (7·0-13·0) in the standard-of-care group (log-rank p=0·26). Among participants with PDR, virological failure was lower in the OLA-guided therapy group than in the standard-of-care group: five (14%) of 35 compared with 13 (50%) of 26; p=0·0020). Among those prescribed NNRTI-based ART, participants given efavirenz were less likely to have virological failure than were those receiving nevirapine (odds ratio 0·37, 95% CI 0·22-0·62; p<0·0001). The OLA-guided therapy group had 39 serious non-lethal adverse events and 34 deaths. The standard-of-care group had 34 severe adverse events and 43 deaths, differences that were not significant. Adverse events judged to potentially be due to ART were few and similar between groups, with 17 (16%) in the OLA-guided therapy group and 16 (16%) in the standard-of-care group (p=0·90). INTERPRETATION: Our finding that OLA testing for PDR reduced virological failure in only those with specific PDR mutations suggests that PDR poses less of a risk for virological failure than that predicted by past prevalence estimates, and that the value of PDR testing to reduce virological failure should be assessed for antiretroviral treatment regimens. FUNDING: US National Institutes of Health.

Minority and majority pretreatment HIV-1 drug resistance associated with failure of first-line nonnucleoside reverse-transcriptase inhibitor antiretroviral therapy in Kenyan women.

OBJECTIVES: Among women initiating first-line nonnucleoside reverse-transcriptase inhibitor (NNRTI)-based-ART with and without a history of single-dose nevirapine (sdNVP) with or without zidovudine with or without lamivudine (ZDV with and without 3TC) for prevention of mother-to-child HIV transmission (PMTCT), we hypothesized that pre-ART HIV-drug resistance would be associated with virologic failure DESIGN/METHODS:: In a prospectively enrolled study, three genotypic drug-resistance assays [oligonucleotide-ligation-assay (OLA), consensus sequencing, and next-generation sequencing by Illumina] were retrospectively performed to detect pre-ART drug resistance. Minority or majority drug-resistant variants identified in pre-ART RNA and/or DNA, a history of antiretrovirals for PMTCT, and other risk factors were assessed for association with virologic failure. RESULTS: Failure occurred in 38/169 (22.5%) women, and was associated with pre-ART drug resistance detected by any assay (OLA of plasma or PBMC, consensus sequencing of PBMC and/or plasma, and next-generation sequencing of PBMC at frequencies of at least 10% and as minority variants; all P < 0.0001). Failure was also associated with PMTCT using sdNVP and ZDV with or without 3TC, but not sdNVP only; however, the longer time-interval between PMTCT and ART initiation observed for sdNVP-only women showed no interaction with failure. Viral loads and OLA of PBMC in longitudinal specimens demonstrated rapid failure and emergence of drug resistance, particularly among sdNVP and ZDV with or without 3TC-experienced women with pre-ART drug-resistant minority variants by next-generation sequencing but without drug resistance by OLA or consensus sequencing. CONCLUSION: Pre-ART drug resistance was detected similarly by OLA of PBMC or plasma and by consensus sequencing, and was associated with virologic failure soon after initiation of first-line NVP-based ART. A history of sdNVP and ZDV with or without 3TC for PMTCT or minority variants detected by next-generation sequencing identified additional women with failure. These findings emphasize the value of assessing individual antiretroviral history, particularly nonsuppressive antiretrovirals with at least two drug classes, and testing for pre-ART drug resistance, including minority variants.