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Mutations in the human immunodeficiency virus type 1 (HIV-1) genome have been hypothesized to occur at all nucleotide positions, including those that confer drug resistance, as the result of high rates of HIV-1 replication, mutation, and recombination [1–3]. Consequently, after exposure to one antiretroviral drug such as nevirapine (NVP), given as a single dose to prevent mother-to-child HIV-1 transmission, drug-resistant variants can rapidly emerge [4–7]. It is well established that such drug-resistant variants, when detected by standard genotype, can compromise virologic responses to combination antiretroviral therapy (cART) [8–10]. For example, in the OCTANE/A5208 trial 1, conducted in African women with prior exposure to single-dose NVP (sdNVP) and who subsequently initiated NVP-based cART, NVP resistance detected by standard genotype at study entry was associated with virologic failure (VF) or death, and lopinavir/ritonavir (LPV/r) was superior to NVP-based cART in sdNVP-exposed women [11]. The impact of minor populations of drug-resistant variants on the response to initial cART has been more controversial, with some studies reporting their association with VF and others finding no association [12–19]. We reported that the risk of VF with NVP-based cART was significantly associated with low frequency (>1%), NVP-resistant variants in African women with prior exposure to sdNVP (OCTANE/A5208 trial 1) [20]. In women who had never been exposed to sdNVP (OCTANE/A5208 trial 2), however, NVP- or LPV/r-based cART showed equivalent virologic efficacy [21]. To investigate the different outcomes of the NVP-based cART arms of trial 1 and trial 2, we performed allele-specific polymerase chain reaction (PCR) on pre-cART samples from women without prior sdNVP exposure (trial 2), to quantify frequencies of the 3 most common NVP resistance mutations (K103N, Y181C, and G190A) and their association with VF or death.

Background. Combination antiretroviral therapy (cART) reduces genital tract human immunodeficiency virus type 1 (HIV-1) load and reduces the risk of sexual transmission, but little is known about the efficacy of cART for decreasing genital tract viral load (GTVL) and differences in sex or HIV-1 subtype. Methods. HIV-1 RNA from blood plasma, seminal plasma, or cervical wicks was quantified at baseline and at weeks 48 and 96 after entry in a randomized clinical trial of 3 cART regimens. Results. One hundred fifty-eight men and 170 women from 7 countries were studied (men: 55% subtype B and 45% subtype C; women: 24% subtype B and 76% subtype C). Despite similar baseline CD4+ cell counts and blood plasma viral loads, women with subtype C had the highest GTVL (median, 5.1 log10 copies/mL) compared to women with subtype B and men with subtype C or B (4.0, 4.0, and 3.8 log10 copies/mL, respectively; P < .001). The proportion of participants with a GTVL below the lower limit of quantification (LLQ) at week 48 (90%) and week 96 (90%) was increased compared to baseline (16%; P < .001 at both times). Women were significantly less likely to have GTVL below the LLQ compared to men (84% vs 94% at week 48, P = .006; 84% vs 97% at week 96, P = .002), despite a more sensitive assay for seminal plasma than for cervical wicks. No difference in GTVL response across the 3 cART regimens was detected. Conclusions. The female genital tract may serve as a reservoir of persistent HIV-1 replication during cART and affect the use of cART to prevent sexual and perinatal transmission of HIV-1.

The 24-week extension of AIDS Clinical Trials Group Protocol 359, a study of human immunodeficiency virus (HIV)‐infected, indinavir-experienced patients, was designed to study the durability of “salvage” treatment regimens. Patients received saquinavir in combination with either ritonavir or nelfinavir and, in addition, delavirdine, adefovir, or both. Patients who demonstrated a virologic response at weeks 12‐16 were eligible to continue therapy in the extension through week 48. Of the 105 eligible subjects who were enrolled in the extension, 86 (82%) completed 48 weeks, and 49 (57%) of those 86 had HIV RNA levels 500 copies/ mL at week 48. For these 86 subjects who completed 48 weeks, the median change in CD4 cell count from baseline was +72 cells/mm 3 . Greater body weight, higher CD4 cell count, and greater degree of phenotypic susceptibility to indinavir and saquinavir at baseline were significantly associated with durable virologic suppression. These results show that some patients who experience treatment failure can demonstrate durable virologic and immunologic responses with salvage antiretroviral regimens. Current treatment guidelines recommend starting therapy for human immunodeficiency virus (HIV) infection with 2 nucleoside analogue reverse-transcriptase inhibitors in combination with 1 or 2 protease inhibitors or a nonnucleoside analogue reversetranscriptase inhibitor [1, 2]. However, 20%‐63% of patients from clinical cohorts experience virologic treatment failure while receiving combination antiretroviral therapy [3‐7]. Recent prospective studies have attempted to identify strategies for treatment of the treatment-experienced patient [8‐13], but these studies have focused primarily on 8‐24-week virologic responses to treatment. The durability of virologic and immunologic re

Objective: In a large multi-center clinical trial of combination reverse transcriptase inhibitors (RTls), we assessed the impact of antiretroviral therapy on neurological function, the relationship between neurological and systemic benefit, and the prognostic value of neurological performance in late HIV-1 infection. Design: Neurological evaluations incorporated in a randomized, multi-center trial of combination antiretroviral therapy. Setting: Forty-two AIDS Clinical Trials Group sites and seven National Hemophilia Foundation sites Patients: Adult HIV-infected patients (n = 1313) with CD4 counts < 50 × 10 6 cells/l. Interventions: Four combinations of reverse transcriptase inhibitors consisting of zidovudine (ZDV), alternating monthly with didanosine (ddl), or in combination with zalcitabine (ddC), ddl or ddl and nevirapine. Main outcome measures: Mean change from baseline of a four-item quantitative neurological performance battery score, the QNPZ-4, administered to 1031 subjects. Results: Triple therapy and ZDV/ddl combination preserved or improved neurological performance over time compared with the alternating ZDV/ddl and ZDV/ddC regimens (P < 0.001), paralleling their impact on survival in the same trial as previously reported. QNPZ-4 scores were predictive of survival (P < 0.001), after adjusting for CD4 counts and HIV-1 plasma RNA concentrations. Conclusions: Combination antiretroviral therapy can have a salutary effect on preserving or improving neurological function. Superior systemic treatments may likewise better preserve neurological function. The significant association of poor neurological performance with mortality, independent of CD4 counts and HIV-1 RNA levels indicates that neurological dysfunction is an important cause or a strong marker of poor prognosis in late HIV-1 infection. This study demonstrates the value of adjunctive neurological measures in large therapeutic trials of late HIV-1 infection.

BackgroundAntiretroviral regimens with simplified dosing and better safety are needed to maximize the efficiency of antiretroviral delivery in resource-limited settings. We investigated the efficacy and safety of antiretroviral regimens with once-daily compared to twice-daily dosing in diverse areas of the world.Methods and findings1,571 HIV-1-infected persons (47% women) from nine countries in four continents were assigned with equal probability to open-label antiretroviral therapy with efavirenz plus lamivudine-zidovudine (EFV+3TC-ZDV), atazanavir plus didanosine-EC plus emtricitabine (ATV+DDI+FTC), or efavirenz plus emtricitabine-tenofovir-disoproxil fumarate (DF) (EFV+FTC-TDF). ATV+DDI+FTC and EFV+FTC-TDF were hypothesized to be non-inferior to EFV+3TC-ZDV if the upper one-sided 95% confidence bound for the hazard ratio (HR) was ≤1.35 when 30% of participants had treatment failure. An independent monitoring board recommended stopping study follow-up prior to accumulation of 472 treatment failures. Comparing EFV+FTC-TDF to EFV+3TC-ZDV, during a median 184 wk of follow-up there were 95 treatment failures (18%) among 526 participants versus 98 failures among 519 participants (19%; HR 0.95, 95% CI 0.72-1.27; p = 0.74). Safety endpoints occurred in 243 (46%) participants assigned to EFV+FTC-TDF versus 313 (60%) assigned to EFV+3TC-ZDV (HR 0.64, CI 0.54-0.76; pConclusionEFV+FTC-TDF had similar high efficacy compared to EFV+3TC-ZDV in this trial population, recruited in diverse multinational settings. Superior safety, especially in HIV-1-infected women, and once-daily dosing of EFV+FTC-TDF are advantageous for use of this regimen for initial treatment of HIV-1 infection in resource-limited countries. ATV+DDI+FTC had inferior efficacy and is not recommended as an initial antiretroviral regimen.Trial registrationwww.ClinicalTrials.gov NCT00084136. Please see later in the article for the Editors' Summary.

Objective : To study the addition of a third human immunodeficiency virus type 1 (HIV-1) reverse transcriptase inhibitor, nevirapine, to the combination of zidovudine and didanosine. Design : A 48-week, randomized, double-blind, placebo-controlled trial at 16 AIDS (acquired immunodeficiency syndrome) Clinical Trials Units. Patients : 398 adults who had HIV-1 infection, had 350 or fewer CD4 + T lymphocytes/mm 3 , and had had more than 6 months of previous nucleoside therapy. Intervention : 1) Either nevirapine or placebo (200 mg/d for 2 weeks, then 400 mg/d thereafter) and 2) open-label zidovudine (600 mg/d) and didanosine (400 mg/d for patients weighing ≥60 kg). Measurements : CD4 + T lymphocyte counts, time to first HIV-1 disease progression event or death, adverse events, and nevirapine levels in plasma samples taken at random were measured in all patients. Plasma levels of HIV-1 RNA ; HIV-1 infectivity titer in peripheral blood mononuclear cells ; serum p24 antigen levels ; and plasma levels of zidovudine and didanosine were measured in patients enrolled at half the study sites. Results : After 48 weeks of study treatment, the patients assigned to the triple-combination regimen (nevirapine, zidovudine, and didanosine) had an 18% higher mean absolute CD4 cell count (95% CI, 7% to 29% ; P = 0.001), a 0.32 log 10 lower mean infectious HIV-1 titer in peripheral blood mononuclear cells (CI, 0.05 to 0.59 log 10 infectious units per million cells ; P = 0.023), and a 0.25 log 10 lower mean plasma HIV-1 RNA level (CI, 0.03 to 0.48 log 10 RNA copies/mL ; P = 0.028) than did patients assigned to the double-combination regimen (zidovudine and didanosine). Severe rashes were more common among patients assigned to receive the triple combination (9% compared with 2% ; P = 0.002). Risk for disease progression did not differ between the two groups (relative hazard of the triple-combination group, 1.24 [CI, 0.75 to 2.06] ; P > 0.2), although the study had only moderate power to detect a major difference. Conclusions : Adding nevirapine to zidovudine and didanosine improved the long-term immunologic and virologic effects of therapy and was associated with severe rash among the patients studied, who had had extensive previous therapy. These results support 1) the continuing development of combinations of more than two antiretroviral drugs to increase and prolong HIV-1 suppression and 2) the potential utility of nevirapine in combination regimens.