Less-drug regimen including atazanavir in maintenance treatment of HIV infection: how, who, when, why?

Simplification of combination antiretroviral therapy (cART) and the brain-a real-life experience

Modern antiretroviral combination therapy (cART) has transformed HIV from a life-threatening infection into a chronic disease. However, the life-long treatment has side effects that frequently have a negative impact on patients' quality of life. Thus, there are some efforts to "simplify" therapy, i.e. apply regimens with three or fewer antiretroviral substances. However, neurologists are relatively sceptical towards this cART "simplification", because the capacity of simplified regimens to access the cerebrospinal fluid (CSF) might be too weak to effectively suppress viral load in this compartment. Thus, data of a big Neuro-AIDS cohort of 4992 HIV-positive patients consecutively recruited over three decades were retrospectively analysed in terms of neurocognitive performance of patients switched to simplified therapy regimens. To test whether simplified drug regimens result in new neuropsychological deficits or the worsening of pre-existing ones in HIV+ patients. Three groups of HIV+ patients were switched from triple therapy to three different two drug regimens (n = 177 to lamivudine/PI, n = 37 to INI/PI, and n = 303 to dual PI); three other groups of patients put from one to an alternative triple combination (n = 290 ABC/3TC/PI, n = 244 TDF/FTC/PI, and n = 158 TDF/FTC/NNRTI) for whatever reason served as controls. All patients were followed up over 4 years maximum. Every patient group improved immunologically and virologically after the switch. However, patients who switched to INI/PI combinations remained stable in neuropsychological tests, while a considerable percentage of patients who switched to other treatments demonstrated a decline. Remarkably, a high percentage of the patients switched to "simplified drug regimens" was not well-controlled virologically before the switch. HIV-positive patients with simplified therapy regimens show some benefit in terms of systemic infection surrogate markers (CD4 ± cell count and plasma viral load); however, neurocognitive deficits do not improve, but remain stable in most cases.

Resistance detected in PBMCs predicts virological rebound in HIV-1 suppressed patients switching treatment

BACKGROUND

Genotypic resistance test (GRT) performed in peripheral blood mononuclear cells (PBMC) represents a chance to evaluate resistance in virologically suppressed HIV infected patients.

OBJECTIVES

To evaluate the impact of baseline resistance detected through PBMC GRT on virological rebound after switching treatment.

STUDY DESIGN

Baseline genotypic susceptibility scores (GSS) from PBMC GRT (DNA-GSS) and from previous cumulative plasma GRTs (when available, pRNA-GSS) were evaluated. Survival analysis was used to assess the probability and predictors of virological rebound (VR).

RESULTS

227 virologically suppressed patients were analysed. Twenty-four months after switching therapy, the probability of VR was 15.3%. Patients showing an intermediate or full resistant DNA-GSS had a higher probability of experiencing VR compared to those carrying a fully susceptible DNA-GSS (27.2% vs. 13.7%, p = 0.001). By multivariable Cox regression, patients with an intermediate/full resistant DNA-GSS, with a nadir CD4 count <100 cell/mm³ and with a shorter time of previous virological suppression showed a higher adjusted hazard of experiencing VR. In a sub-group of 114 patients with previous plasma GRTs available, patients with an intermediate or fully resistance showed by both GSSs (from plasma and PBMCs) had the highest probability of experiencing VR.

CONCLUSIONS

Resistance detected in proviral DNA, together with a low nadir CD4 count and a short previous virological control, predicts VR after therapy switching in virologically suppressed patients. PBMC GRT can be a useful tool for tailoring treatment switch, especially if paired with information about previous cumulative resistance and previous viro-immunological history.

Atazanavir sulfate + cobicistat for the treatment of HIV infection

INTRODUCTION

During last two decades several drugs were developed to offer long-term benefits in terms of virologic efficacy, favourable tolerability and toxicity profiles in treatment of HIV infection. Pharmacokinetics boosting of protease inhibitor allows a higher genetic barrier, as few or no drug-resistant mutations are detected in patients with virologic failure. Areas covered: Atazanavir sulfate + cobicistat (ATV/c) was recently approved for the treatment of HIV-1 infection. Bioequivalence between cobicistat (COBI) and ritonavir (RTV) as a pharmacoenhancer of ATV was established. Additionally, randomized clinical trials demonstrated that ATV/c and ATV/ritonavir had comparable efficacy and safety profiles. Low rates of virologic failure and no ATV resistance mutations were observed in these clinical trials. Therefore, COBI shows increased advantages over RTV, such as no activity against HIV, fewer drug-drug interactions and better solubility, which promotes coformulation strategies with less pill burden, better tolerability, and, potentially, higher life-long treatment adherence. Expert commentary: ATV/c regimen supports its useas an effective treatment option for HIV-1 infected patients with increased cardiovascular disease and chronic kidney disease risk associated with aging. In addition, ATV/c is a new opportunity to expand the strategy of switch to a dual therapy to lower the risk of long-term toxicities as well as the advantage of its cost-benefit.