Ultrasensitive assessment of residual low-level HIV viremia in HAART-treated patients and risk of virological failure.

BACKGROUND: Low-level viremia (LLV) is measurable, with enhanced assays, in many subjects with HIV RNA levels <50 copies per milliliter. The clinical consequences of LLV are unknown. METHODS: In a prospective study in HIV-1-infected adults, HIV RNA levels were determined with an ultrasensitive test (3 copies/mL) based on a real time polymerase chain reaction. The primary end point was to evaluate LLV prediction of virological failure, defined as a confirmed plasma HIV RNA level >50 copies per milliliter. RESULTS: One thousand two hundred fourteen patients were followed for (mean) 378 days. At baseline, 71.5% were <3 copies per milliliter below the limit of detection (BLD). The risk of failing highly active antiretroviral therapy in the following 4 months for patients BLD was 0.4% compared with a 3.2% risk for those with LLV (P < 0.0001; odds ratio: 7.52). There was a significant (P < 0.0001) linear relationship between the HIV RNA and the risk of virologic failure. LLV receiver operating curve analysis showed an area under the curve of 0.76 (95% confidence interval: 0.68 to 0.84) that significantly (P < 0.0001) predicted the risk of failure. The risk of an unconfirmed viral blip was higher in patients with LLV (3.9%) than in those BLD (1.1%) (P < 0.0001; odds ratio: 3.56). Longer exposure to antiretrovirals, current use of nonnucleoside reverse transcriptase inhibitors, longer time BLD, and current HIV RNA <3 copies per milliliter were independent predictors of a positive outcome. INTERPRETATION: Viral replication may be the cause of LLV, at least in some patients. A LLV >3 copies per milliliter is linked to a significant increment of risk of virological failure leading to drug resistance. Patients with measurable LLV should be managed to better evaluate, over time, the risk of failure and to limit its consequences.

CD4 cell-guided scheduled treatment interruptions in HIV-infected patients with sustained immunologic response to HAART.

OBJECTIVE: To compare continuous HAART with a CD4 cell-driven scheduled treatment interruption (STI) strategy. METHODS: LOng Term Treatment Interruption study is a randomized, controlled, prospective trial. Patients with CD4 cell counts more than 700 cells/microl were eligible, and the immunologic threshold to resume HAART was 350 cells/microl. The primary end point was the development of an opportunistic disease, death from any cause or the occurrence of diseases, other than opportunistic, requiring hospital admission. Secondary end points were major adverse effects, virologic failures and therapeutic costs. RESULTS: Three hundred and twenty-nine patients were randomized 1: 1. Total follow-up was 1388 person-years (mean 4.2 years). Patients in the STI group stopped therapy for a total of 241 STI cycles, their mean off-therapy period was 65.3% of the follow-up. The primary end point occurred in 12.1% of patients on STI and in 11.6% of controls [odds ratio 1.05; 95% confidence interval 0.54-2.05]. A higher proportion of patients in the STI arm were diagnosed with pneumonia (P = 0.037), whereas clinical events influencing the cardiovascular risk of patients were significantly (P < 0.0001) more frequent among controls. Eight patients (4.8%) in the STI group and 11 (6.7%) controls developed viral resistance [odds ratio 0.79, 95% confidence interval 0.27-1.81]. The mean daily therapeutic cost was 20.29 euro for controls and dropped to 9.07 euro in the STI arm (P < 0.0001). CONCLUSION: The two strategies may be considered clinically equivalent. CD4 cell-guided STIs seem a possible alternative for chronically infected individuals responding to HAART provided that CD4 cell decrements would be steadily maintained above a safe threshold.

Prediction of Virologic Outcome of Salvage Antiretroviral Treatment by Different Systems for Interpreting Genotypic HIV Drug Resistance.

The authors assessed the predictive capacity of 3 rule-based algorithms (Bergamo, Stanford University, Rega Institute) for HIV genotypic interpretation. A total of 1132 postgenotypic regimens in 533 patients were considered. The genotypic sensitivity score (GSS) was strongly associated (P < .0001) with the virologic outcome (1 log HIV-RNA reduction). The 3 algorithms had a highly significant prediction efficiency. The Bergamo algorithm receiver-operating characteristic curve area under the curve (AUC) for the prediction of >/=1 log HIV-RNA reduction was 0.753 (95% confidence interval, 0.725-0.781), testifying that the prediction was significantly different (P < .0001) from simple chance. The AUCs obtained by the 2 other systems were similar (0.752 Stanford; 0.741 Rega). The predictive capacity of the algorithms was not influenced by the type of antiviral drugs used. The 3 considered rule-based algorithms for the interpretation of HIV genotypic resistance yield congruent results and may effectively predict the virologic outcome of rescue therapy. Their use may help clinicians in interpreting mutational patterns and in making therapeutic choices.

Reasons for discontinuation of nevirapine-containing HAART: results from an unselected population of a large clinical cohort.

OBJECTIVES: To evaluate the frequency of and predictive factors for nevirapine-based highly active antiretroviral therapy (HAART) discontinuation. METHODS: All patients receiving nevirapine as a component of HAART at our centre were retrospectively evaluated for efficacy and tolerability. Logistic regression was used to evaluate the influence of baseline characteristics on the outcome and Kaplan-Meier (KM) estimates to evaluate time-dependent variables. RESULTS: Between January 1999 and June 2006, 582 patients (72% males) received 744 nevirapine-based HAART regimens. Naive patients counted for 83 of these regimens; of the remaining 661 regimens administered to experienced patients, 306 were failing virologically and 355 were undergoing simplification strategies. A once-a-day schedule was used in 136 patients. The likelihood of maintaining the nevirapine-based regimen was statistically (P < 0.0001 in both cases) influenced by the patient's status (mean KM estimate of 812 days for virological failures, 1294 for naive patients and 1657 for treatment simplifications) and by the dosing schedule (once-daily 1315 days; twice-daily 1198 days). The most frequent reason for treatment discontinuation was resistance (17.5%) followed by reduced tolerability (16.3%), patient's decision (14%) and treatment strategies such as structured treatment interruptions (13.8%). During 10.2% of treatments, a grade 3 or greater increase in aminotransferase levels was observed, reflecting an overall incidence rate equal to 5.3 cases per 100 person-years. This lead to treatment discontinuation in 3.9% of cases. CONCLUSIONS: Nevirapine, especially when used in simplification strategies, enables doctors to extend the use of HAART over a long period of time. The risk of drug-induced hepatotoxicity is low, but nevirapine should be used with caution in patients co-infected with hepatitis C virus or with elevated liver function tests. As with any decision to prescribe a drug, a careful evaluation of the potential risks and benefits of using nevirapine must be made for each individual.

Quadruple-drug induction HAART in advanced HIV infection.

A randomized controlled study exploring an induction-maintenance strategy was performed with a quadruple-drug regimen: zidovudine/lamivudine/abacavir/nevirapine. The study was prematurely interrupted due to the high proportion of adverse events. The median time on protocol-defined therapy was 110 days; 13/28 (46%) patients interrupted therapy and 2/6 tested patients selected praecox viral mutants. Despite this, we observed a significant (p

Similar adherence rates favor different virologic outcomes for patients treated with nonnucleoside analogues or protease inhibitors.

BACKGROUND: This prospective study verified the effect of adherence on the risk of virologic failure. METHODS: At enrollment in the study, a total of 543 patients who were following a steady (duration, >or=6 months) and effective (viral load, <50 human immunodeficiency virus [HIV] RNA copies/mL) regimen of highly active antiretroviral therapy (HAART) completed a self-reported questionnaire derived from the Adult AIDS Clinical Trials Group Adherence Follow-up Questionnaire. Patients were followed up for the subsequent 6 months to document virologic failure, which was defined as 2 consecutive viral load measurements of >500 HIV RNA copies/mL. RESULTS: Only the type of treatment and the adherence rate at baseline were significantly associated with the virologic end point. Among patients who reported an adherence rate of 95%. When analysis was adjusted according to the type of regimen received, patients who were receiving protease inhibitor (PI)-based HAART and who had an adherence rate of up to 85% had a virologic failure rate of >20%, whereas, only for patients who were receiving nonnucleoside reverse-transcriptase inhibitor (NNRTI)-based HAART and who had an adherence rate of 10%. For the comparison of NNRTI-treated patients and PI-treated patients with an adherence rate of 75%-95%, the odds ratio was 0.157 (95% confidence interval, 0.029-0.852). The number of pills and daily doses received correlated with the reported adherence rate. CONCLUSIONS: Patients receiving NNRTIs report a higher rate of adherence than do patients receiving PIs. Adherence is significantly influenced by the number of pills and daily doses received. Low adherence is a major determinant of virologic failure; however, different therapies have different cutoff values for adherence that determine a significant increment of risk.

Outcome of 2 simplification strategies for the treatment of human immunodeficiency virus type 1 infection.

In a prospective, open-label, 104-week study, patients who were infected with human immunodeficiency virus type 1 (virus load, <50 copies/mL) and who were receiving protease inhibitor-based therapy were randomly assigned to continue treatment with a protease inhibitor or to replace it with abacavir or efavirenz. Treatment failure, defined as virological failure (virus load, >500 copies/microL) or any clinical or biochemical adverse event with a grade of >or=3 (on the basis of the World Health Organization [WHO] or American Heart Association [AHA] scales), was the primary outcome measurement. Failure rates were more frequent in the group treated with protease inhibitors (P<.01), and there were no significant differences in the rate of treatment failure between the group treated with efavirenz and the group treated with abacavir. Tolerability was better in the groups treated with abacavir or with efavirenz versus those treated with protease inhibitors. Fewer patients who received efavirenz experienced viral rebound. Among all groups, the mean increase in the CD4 cell count was 131 cells/microL (P<.001), with no significant difference between groups. This switching strategy maintains optimal levels of virological suppression and may improve lipid profiles in most patients.

Salvage therapy with abacavir in HIV-1-infected patients with previously documented M184V mutation: a possibility of NRTI recycling.

We evaluated in an open-label, randomized, controlled, pilot trial if the re-emergence of previously selected resistant strains, harbouring M184V mutation, could be modulated by the use of different drug associations as components of the new antiretroviral regimens. In addition, we assessed the clinical relevance of this mutation on the management of heavily pretreated HIV-infected patients. The primary end-point of the study was the reselection of M184V mutation. Secondary end-points were the variation over time of HIV RNA plasma levels and CD4 cell counts and the progression of HIV disease. The primary population for efficacy analysis was the intention-to-treat exposed population. After a run-in phase consisting in a new treatment regimen excluding either lamivudine (3TC) or abacavir (ABC) so as to clear the previously documented M184V mutation, 18 patients with an HIV RNA plasma level greater than 10000 copies/ml were randomized to receive an antiretroviral drug regimen (at least three drugs) including either ABC or the association of ABC+3TC. All patients were naive to ABC. The M184V mutation reappeared in 1/9 patients in the ABC group and in 8/9 patients in the ABC+3TC group (P<0.003, 95% CI: 0.5-1). In the ABC group we observed a rapid decrement of viral load that was maintained throughout all the study period (P<0.05). On the contrary, in the ABC+3TC group, after a transient decrement at 2 months, a progressive increment towards baseline values was observed. The proportion of patients with a viral load reduction of at least 0.5 logs at 12 months was significantly higher in the ABC group: 8/9 patients vs 3/9 (P=0.05, 95% CI: 0.2-0.92). Similarly, from an immunological point-of-view, the increase at all time points (since randomization) in CD4 cell count was statistically significant in the ABC group (P<0.01), while no difference was observed in the ABC+3TC group. The possibility of a successful use of ABC in salvage regimens opens alternative therapeutic options for heavily pretreated patients with previously documented M184V mutation. Further studies should clarify whether this is true for other drugs of the nucleoside analogues class.

Simpler regimens may enhance adherence to antiretrovirals in HIV-infected patients.

BACKGROUND: Optimal adherence to highly active antiretroviral therapy (HAART) is necessary to achieve the best and the most durable benefit. Many factors may influence compliance to such demanding regimens, and their identification may help in the design of strategies to enhance adherence. PURPOSE: To assess the factors associated with lower compliance to therapy, the causes of nonadherence, and the relation of nonadherence with virologic response. METHOD: We performed an observational, cross-sectional study on HIV-infected patients (pts) receiving unrestricted HAART and attending our clinic from January to May 2001. Pts completed a self-administered (ACTG modified) questionnaire on adherence to their therapy. Virologic response was defined as undetectable viral load at the time of interview. A regression model was used to determine predictors of adherence. RESULTS: 597 out of 623 pts (95.8%) completed the survey. Mean age was 38.2 years (range, 18-79). A total of 448 pts (75.0%) were men, 323 (54.1%) were intravenous drug users, 196 (32.8%) were heterosexuals, 76 (12.7%) were men who have sex with men. Mean time on therapy was 49.3 months (range, 4-145). All pts were on stable therapy (> 4 months), 173 pts (29%) were on their first HAART regimen, 309 pts (51.7%) were on NNRTI-based regimen, and 288 pts (48.2%) were on a PI-containing treatment. A total of 304 pts (50.9%) were categorized as adherent (p = .024). Multiple logistic regression showed that older age (p = .002), lower number of pills (p = .024), fewer daily doses (p = .002), and shorter time on therapy (p < .001) were factors associated with adherent behavior. Forgetfulness (59.3%), being away from home (50.2%), and problems with schedule (37.6%) were the most frequent causes of nonadherence. Adherent pts were more likely to have undetectable viral load than nonadherent pts (76.5% vs. 55.3%; p <.0001). CONCLUSION: Younger age, higher number of pills, higher frequency of doses, and longer time on therapy were predictors of nonadherent behavior. Optimal adherence correlated with the best virologic response. Simpler regimens with a lower number of pills and doses may help patients' compliance to therapy.