Durability of lopinavir/ritonavir monotherapy in individuals with viral load ≤50 copies/ml in an observational setting

Fungi as Part of the Microbiota and Interactions with Intestinal Bacteria

The human microbiota consists of bacteria, archaea, viruses, and fungi that build a highly complex network of interactions between each other and the host. While there are many examples for commensal bacterial influence on host health and immune modulation, little is known about the role of commensal fungi inside the gut community. Up until now, fungal research was concentrating on opportunistic diseases caused by fungal species, leaving the possible role of fungi as part of the microbiota largely unclear. Interestingly, fungal and bacterial abundance in the gut appear to be negatively correlated and disruption of the bacterial microbiota is a prerequisite for fungal overgrowth. The mechanisms behind bacterial colonization resistance are likely diverse, including direct antagonism as well as bacterial stimulation of host defense mechanisms. In this work, we will review the current knowledge of the development of the intestinal bacterial and fungal community, the influence of the microbiota on human health and disease, and the role of the opportunistic yeast C. albicans. We will furthermore discuss the possible benefits of commensal fungal colonization. Finally, we will summarize the recent findings on bacterial-fungal interactions.

Refining criteria for selecting candidates for a safe lopinavir/ritonavir or darunavir/ritonavir monotherapy in HIV-infected virologically suppressed patients

Objective

The primary objective of this study was to estimate the incidence of treatment failure (TF) to protease inhibitor monotherapies (PI/r-MT) with lopinavir/ritonavir (LPV/r) or darunavir/ritonavir (DRV/r).

Design

A multicenter cohort of HIV-infected patients with viral load (VL) ≤50 copies/mL, who underwent a switch from any triple combination therapy to PI/r-MT with either LPV/r or DRV/r.

Methods

VL was assessed in each center according to local procedures. Residual viremia was defined by any HIV-RNA value detectable below 50 copies/mL by a Real-Time PCR method. Standard survival analysis was used to estimate the rate of TF (defined by virological failure or interruption of monotherapy or reintroduction of combination therapy). A multivariable Cox regression analysis with automatic stepwise procedures was used to identify factors independently associated with TF among nadir and baseline CD4+ counts, residual viremia, time spent with <50 HIV-RNA copies/mL before switch, history of virological failure, HCV co-infection, being on a PI/r and hemoglobin concentrations at baseline.

Results

Six hundred ninety patients fulfilled the inclusion criteria and were included in this analysis. Their median follow-up was 20 (10–37) months. By month 36, TF occurred in 176 (30.2%; 95% CI:25.9–34.5) patients. Only CD4+ nadir counts (adjusted hazard ratio [aHR] = 2.03 [95% CI: 1.35, 3.07] for counts ≤100 vs. >100 cells/μL) and residual viremia (aHR = 1.48 [95% CI: 1.01–2.17] vs. undetectable VL) were independently associated to TF.

Conclusions

Residual viremia and nadir CD4+ counts <100 cells/μL should be regarded as the main factors to be taken into account before considering switching to a PI/r-MT.

Factors associated with virological rebound in HIV-infected patients receiving protease inhibitor monotherapy

OBJECTIVE

The Protease Inhibitor Monotherapy Versus Ongoing Triple Therapy (PIVOT) trial found that protease inhibitor monotherapy as a simplification strategy is well tolerated in terms of drug resistance but less effective than combination therapy in suppressing HIV viral load. We sought to identify factors associated with the risk of viral load rebound in this trial.

METHODS

PIVOT was a randomized controlled trial in HIV-positive adults with suppressed viral load for at least 24 weeks on combination therapy comparing a strategy of physician-selected ritonavir-boosted protease inhibitor monotherapy versus ongoing triple therapy. In participants receiving monotherapy, we analysed time to confirmed viral load rebound and its predictors using flexible parametric survival models.

RESULTS

Of 290 participants initiating protease inhibitor monotherapy (80% darunavir, 14% lopinavir, and 6% other), 93 developed viral load rebound on monotherapy. The risk of viral load rebound peaked at 9 months after starting monotherapy and then declined to approximately 5 per 100 person-years from 18 months onwards. Independent predictors of viral load rebound were duration of viral load suppression before starting monotherapy (hazard ratio 0.81 per additional year <50 copies/ml; P < 0.001), CD4 cell count (hazard ratio 0.73 per additional 100 cells/μl for CD4 nadir; P = 0.008); ethnicity (hazard ratio 1.87 for nonwhite versus white, P = 0.025) but not the protease inhibitor agent used (P = 0.27). Patients whose viral load was analysed with the Roche TaqMan-2 assay had a 1.87-fold risk for viral load rebound compared with Abbott RealTime assay (P = 0.012).

CONCLUSION

A number of factors can identify patients at low risk of rebound with protease inhibitor monotherapy, and this may help to better target those who may benefit from this management strategy.

Simplification to atazanavir/ritonavir monotherapy for HIV-1 treated individuals on virological suppression: 48-week efficacy and safety results

OBJECTIVES

The objective of this study was to assess the 48-week virological efficacy of atazanavir/ritonavir (ATV/r) monotherapy vs. ATV/r along with two nucleoside reverse transcriptase (NRTIs) in HIV-1 treated individuals with HIV-RNA less than 50 copies/ml.

METHODS

A multicentre, randomized, open-label, noninferiority trial. HIV-1 treated individuals on ATV/r 300/100 mg along with two NRTIs were randomized to receive ATV/r monotherapy or to maintain their antiretroviral regimen. The primary endpoint was the confirmed viral rebound (CVR: two consecutive HIV-RNA >50 copies/ml) or treatment discontinuation for any reason. Individuals who experienced CVR on ATV/r monotherapy reintroduced NRTIs and discontinued the study if HIV-RNA was more than 50 copies/ml after 12 weeks since reintensification.

RESULTS

One hundred and three patients enrolled. By week 48, 11 patients in ATV/r arm and two in ATV/r along with two NRTIs experienced CVR; four (8%) patients in ATV/r and eight (15%) in ATV/r along with two NRTIs discontinued. At the 48-week primary efficacy analysis (re-intensification = failure), treatment success was 73% in ATV/r arm and 85% in ATV/r along with two NRTIs [difference -12.1%, 95% confidence interval (95% CI) -27.8 to 2.1]. According to the analysis considering re-intensification is equal to success, treatment success was 92% in ATV/r arm and 85% in the ATV/r along with two NRTIs arm (difference 7.5%, 95% CI -4.7 to 19.8). At CVR, no mutation was observed in ATV/r arm and reintensification with NRTIs was effective in all individuals. Overall, Grade 3-4 (P = 0.003) and grade 3-4 drug-related (P = 0.027) adverse events were less frequent in ATV/r arm. A significant increase in total and low-density lipoprotein (LDL)-cholesterol was observed as well as a significant improvement in high-density lipoprotein (HDL)-cholesterol, fasting glucose, liver fibrosis and alkaline phosphatase was observed in ATV/r monotherapy in comparison with ATV/r along with two NRTIs.

CONCLUSION

ATV/r monotherapy treatment simplification showed lower virological efficacy in comparison with maintaining triple therapy; NRTIs reintroduction was effective in all the individuals.

Budget impact analysis of antiretroviral less drug regimen simplification in HIV-positive patients on the Italian National Health Service

Background

Deintensification and less drug regimen (LDR) antiretroviral therapy (ART) strategies have proved to be effective in terms of maintaining viral suppression in human immunodeficiency virus (HIV)-positive patients, increasing tolerability, and reducing toxicity of antiretroviral drugs administered to patients. However, the economic impact of these strategies have not been widely investigated. The aim of the study is to evaluate the economic impact that ART LDR could have on the Italian National Health Service (INHS) budget.

Methods

A budget impact model was structured to assess the potential savings for the INHS by the use of ART LDR for HIV-positive patients with a 3 year perspective. Data concerning ART cost, patient distribution within different ARTs, and probabilities for patients to change ART on a yearly basis were collected within four Italian infectious diseases departments, providing ART to 13.7% of the total number of patients receiving ART in Italy.

Results

The LDR investigated (protease inhibitor-based dual and monotherapies) led to savings for the hospitals involved when compared to the “do nothing” scenario on a 3 year basis, between 6.7% (23.11 million €) and 12.8% (44.32 million €) of the total ART expenditures. The mean yearly cost per patient is reduced from 9,875 € in the do nothing scenario to a range between 9,218 € and 8,615 €. The use of these strategies within the four departments involved would have led to a reduction of ART expenditures for the INHS of between 1.1% and 2.1% in 3 years.

Conclusion

ART LDR simplification would have a significant impact in the reduction of ART-related costs within the hospitals involved in the study. These strategies could therefore be addressed as a sustainable answer to the public financing reduction observed within the INHS in the last year, allowing therapies to be dispensed without affecting the quality of the services provided.