Week 96 efficacy and safety of darunavir/ritonavir monotherapy vs. darunavir/ritonavir with two nucleoside reverse transcriptase inhibitors in the PROTEA trial.

OBJECTIVES: PROTEA is a randomized controlled trial to assess the efficacy and safety of darunavir/ritonavir (DRV/r) monotherapy as an alternative to triple therapy. METHODS: Patients fully suppressed on first-line antiretrovirals (viral load < 50 HIV-1 RNA copies/mL) were switched to DRV/r 800/100 mg once daily, either as monotherapy (n = 137) or with two nucleoside reverse transcriptase inhibitors (NRTIs) (n = 136). Treatment failure was HIV-1 RNA level ≥ 50 copies/mL at week 96 or discontinuation of study treatment [Food and Drug Administration (FDA) snapshot algorithm]. RESULTS: Patients were mainly male and white, with mean age 44 years. In the primary efficacy analysis, the percentage of patients with HIV-1 RNA < 50 copies/mL by week 96 [intent to treat (ITT)] was lower in the DRV/r monotherapy arm (103 of 137 patients; 75%) than in the triple therapy arm (116 of 136 patients; 85%) [difference -10.1%; 95% confidence interval (CI) -19.5, -0.7%]. In the switch-included analysis, monotherapy was noninferior to triple therapy. In a post hoc analysis, for patients with nadir CD4 count ≥ 200 cells/µL, rates of HIV-1 RNA suppression were 82 of 96 patients (85%) in the DRV/r monotherapy arm and 88 of 106 patients (83%) in the triple therapy arm. No treatment-emergent primary protease inhibitor mutations were detected in either arm. The frequency of adverse events was similar in the two arms; however, one patient in the monotherapy arm was hospitalized with HIV encephalitis and elevated cerebrospinal fluid HIV-1 RNA. CONCLUSIONS: In this study, in patients with HIV-1 RNA < 50 copies/mL at baseline, switching to DRV/r monotherapy showed lower efficacy vs. triple therapy at week 96 in the primary ITT switch-equals-failure analysis, particularly in patients with CD4 counts < 200 cells/µL.

Impact of baseline HIV-1 RNA levels on initial highly active antiretroviral therapy outcome: a meta-analysis of 12,370 patients in 21 clinical trials*.

BACKGROUND: Individual randomized trials of first-line antiretroviral treatment do not consistently show an association between higher baseline HIV-1 RNA and lower efficacy. METHODS: A MEDLINE search identified 21 HIV clinical trials with published analyses of antiretroviral efficacy by baseline HIV-1 RNA, using a standardized efficacy endpoint of HIV-1 RNA suppression <50 copies/mL at week 48. RESULTS: Among 21 clinical trials identified, eight evaluated only nonnucleoside reverse transcriptase inhibitor (NNRTI)-based combinations, eight evaluated only protease inhibitor-based regimens and five compared different treatment classes. Ten of the trials included tenofovir (TDF)/emtricitabine (FTC) as only nucleoside reverse transcriptase inhibitor (NRTI) backbone, in addition but not restricted to abacavir (ABC)/lamivudine (3TC) (n = 7), zidovudine (ZDV)/3TC (n = 4) and stavudine (d4T)/3TC (n = 1). Across trials, the mean percentage of patients achieving HIV-1 RNA < 50 copies/mL at week 48 was 81.5% (5322 of 6814) for patients with baseline HIV-1 RNA < 100 000, vs. 72.6% (3949 of 5556) for patients with HIV-1 RNA > 100 000 copies/mL. In the meta-analysis, the absolute difference in efficacy between low and high HIV-1 RNA subgroups was 7.4% [95% confidence interval (CI) 5.9-8.9%; P < 0.001]. This difference was consistent in trials of NNRTI-based treatments (difference = 6.9%; 95% CI 4.3-9.6%), protease inhibitor-based treatments (difference = 8.4%; 95% CI 6.0-10.8%) and integrase or chemokine (C-C motif) receptor 5 (CCR5)-based treatments (difference = 6.0%; 95% CI 2.1-9.9%) and for trials using TDF/FTC (difference = 8.4%; 95% CI 6.0-10.8%); there was no evidence for heterogeneity of this difference between trials (Cochran's Q test; not significant). CONCLUSIONS: In this meta-analysis of 21 first-line clinical trials, rates of HIV-1 RNA suppression at week 48 were significantly lower for patients w ith baseline HIV-1 RNA > 100 000 copies/mL (P < 0.001). This difference in efficacy was consistent across trials of different treatment classes and NRTI backbones.

The MONET trial: week 144 analysis of the efficacy of darunavir/ritonavir (DRV/r) monotherapy versus DRV/r plus two nucleoside reverse transcriptase inhibitors, for patients with viral load < 50 HIV-1 RNA copies/mL at baseline.

BACKGROUND: In the MONotherapy in Europe with Tmc114 (MONET) trial, darunavir/ritonavir (DRV/r) monotherapy showed noninferior efficacy vs. two nucleoside reverse transcriptase inhibitors (NRTIs) plus DRV/r at the primary 48-week analysis. The trial was continued to week 144 to assess the durability of the results. METHODS: A total of 256 patients with viral load < 50 HIV-1 RNA copies/mL on current highly active antiretroviral therapy (HAART) for at least 6 months switched to DRV/r 800/100 mg once daily, either as monotherapy (n=127) or with two NRTIs (n=129). Treatment failure was defined as two consecutive HIV RNA levels above 50 copies/mL [time to loss of virological response (TLOVR)] by week 144, or discontinuation of study drugs. RESULTS: Eighty-one per cent of patients were male and 91% were Caucasian, and they had a median baseline CD4 count of 575 cells/uL. More patients in the DRV/r monotherapy arm had hepatitis C virus coinfection at baseline than in the control arm (18% vs. 12%, respectively). By week 144, the percentage of patients with HIV RNA < 50 copies/mL [intent to treat (ITT), TLOVR, switch=failure method] was 69% vs. 75% in the DRV/r monotherapy and triple therapy arms [difference= -5.9%; 95% confidence interval (CI) -16.9%, +5.1%]; by a strict ITT analysis (switches not considered failures), the percentage of patients with HIV RNA < 50 copies/mL was 84% vs. 83.5%, respectively (difference= +0.5%; 95% CI -8.7%, +9.7%). Twenty-one and 13 patients had two consecutive HIV RNA results above 50 copies/mL in the DRV/r monotherapy arm and triple therapy arm, respectively, of whom 18 of 21 (86%) and 10 of 13 (77%) had HIV RNA < 50 copies/mL at week 144. CONCLUSIONS: In this study, for patients with HIV RNA < 50 copies/mL at baseline, switching to DRV/r monotherapy showed noninferior efficacy to DRV/r plus two NRTIs in a strict ITT (switches not considered failures) analysis, but not in a TLOVR switch equals failure analysis.

Predictors of treatment failure during highly active antiretroviral therapy (racing trial).

PURPOSE: To determine factors associated with virological failure during long-term treatment with the triple combination of saquinavir soft gel capsule, zalcitabine and zidovudine. METHOD: Open-label, prospective, multicentre study undertaken in private practices and the outpatient department of the Auguste-Viktoria-Hospital. A total of 95 patients with plasma HIV RNA > 5000 copies/ml who had received no more than 6 months pre-treatment with NRTIs and no prior PI therapy received saquinavir soft gel, zalcitabine and zidovudine for 52 weeks, before being randomly assigned to either remain on therapy or switch to nelfinavir, lamivudine and zidovudine for further 52 weeks. RESULTS: Combination therapy with saquinavir, zalcitabine and zidovudine was found to be effective and well tolerated, with virological response to therapy maintained for up to 2 years. In patients responding to therapy, switching to a novel triple regimen did not result in a virological or immunological worsening, but it did not confer an additional clinical benefit. Factors predictive of early treatment failure (virological failure within 16 weeks of treatment initiation) included high viral load and presence of RT mutations at baseline (OR: 0.30, 95% CI 0.11 0.83 and OR 0.13, 95% CI 0.03 0.52, respectively), with baseline viral load and the development of genotypic mutations on therapy being predictive of late treatment failure (16 52 weeks; OR: 0.15, 95% 0.05 0.46 and OR: 0.26, 95% CI < 0.001 1.16, respectively). Plasma saquinavir concentration < 50 mg/ml at 4 weeks was also found to be an independent risk factor for both early and late treatment failure (OR: 1.80, 95% CI 1.23 2.64 and OR: 1.16, 95% CI 0.84 1.60, respectively). CONCLUSIONS: While antiretroviral drug resistance appears to be a principal cause of treatment failure, other factors such as inadequate drug plasma concentrations also play a role.