Metabolic and kidney disorders correlate with high atazanavir concentrations in HIV-infected patients: is it time to revise atazanavir dosages?

Obesity Modifies the Relationship Between Raltegravir and Dolutegravir Hair Concentrations and Body Weight Gain in Women Living with HIV

Integrase strand-transfer inhibitors (INSTIs) are associated with weight gain in women living with HIV (WLH). Relationships between drug exposure, baseline obesity, and INSTI-associated weight gain remain unclear. Data from 2006 to 2016 were analyzed from virally suppressed WLH enrolled in the Women's Interagency HIV Study, who switched/added an INSTI to antiretroviral therapy: [raltegravir (RAL), dolutegravir (DTG), or elvitegravir (EVG)]. Percent body weight change was calculated from weights obtained a median 6 months pre-INSTI and 14 months post-INSTI initiation. Hair concentrations were measured with validated liquid chromatography-mass spectrometry (MS)/MS assays. Baseline (preswitch) weight status evaluated obese (body mass index, BMI, ≥30 kg/m2) versus nonobese (BMI <30 kg/m2). Mixed models examined the drug hair concentration*baseline obesity status interaction for each INSTI. There were 169 WLH included: 53 (31%) switched to RAL, 72 (43%) to DTG, and 44 (26%) to EVG. Women were median age 47-52 years, predominantly Non-Hispanic Black, median CD4 counts >500 cells/mm3, >75% with undetectable HIV-1 RNA. Over ∼1 year, women experienced median increases in body weight: 1.71% (-1.78, 5.00) with RAL; 2.40% (-2.82, 6.50) with EVG; and 2.48% (-3.60, 7.88) with DTG. Baseline obesity status modified the relationship between hair concentrations and percent weight change for DTG and RAL (p's < 0.05): higher DTG, yet lower RAL concentrations were associated with greater weight gain among nonobese women. Additional pharmacologic assessments are needed to understand the role of drug exposure in INSTI-associated weight gain.

Ureterolithiasis in Human Immunodeficiency Virus (HIV) Patients Treated with Single-Use Ureteroscope: A Case Report

BACKGROUND The number of HIV-positive patients is increasing worldwide. Such patients with upper urinary tract stones have been treated primarily with flexible ureteroscopy. CASE REPORT Two patients with HIV and upper urinary tract stones were treated with a single-use digital flexible ureteroscope between July 2021 and January 2022. Both cases were treated by transurethral ureteroscope lithotripsy with a Guangzhou Redpine single-use digital flexible ureteroscope. This is also the first reported case of using a disposable ureteral flexible scope to manage a patient with upper urinary tract stones in combination with HIV. The holmium laser power was set to 0.2-0.6j/20-50 Hz for fragmentation and 1.0-1.5j/10-20 Hz for the dusting of the stones. Renal stones larger than 1 cm were dusted to around 1 cm first, and then a lithotripsy basket was used to remove them. The f5 Polaris Ultra ureteral stent was implanted during the procedure. The operations went smoothly. Four weeks after surgery, CT scans revealed a 4 mm stone remnant in one case, and the ureteral stent was removed in both cases. After 3 months, a kidney, ureter, and bladder X-ray revealed no stones remaining in the case that had earlier shown a 4 mm stone residual. In both cases, the stone composition was made up of calcium oxalate monohydrate and calcium oxalate dihydrate stones. CONCLUSIONS A single-use flexible ureteroscope has a proven clinical benefit in treating HIV-combined upper urinary tract stones. After the operations, there were no urinary infections, bleeding, or other complications in either patient.

Drug-Drug Interactions Between Antiretrovirals and Carbamazepine/Oxcarbazepine: A Real-Life Investigation

BACKGROUND

Carbamazepine and oxcarbazepine are potent modulators of metabolic enzymes. Hence, potential drug-drug interactions (DDIs) may occur between these 2 drugs and antiretrovirals. Here, we aimed to assess the relevance of these drug-drug interactions in real-life clinical settings.

METHODS

Patients treated concomitantly with carbamazepine or oxcarbazepine and antiretrovirals for at least 3 months were considered. Data on therapeutic drug monitoring (TDM) of both antiepileptic and antiretrovirals as trough concentrations were collected. HIV-infected patients not concomitantly treated with antiepileptic drugs and who underwent TDM for antiretrovirals in the previous 2 years were considered as controls.

RESULTS

Eleven HIV-positive patients prescribed carbamazepine or oxcarbazepine were identified. All the TDM evaluations for carbamazepine and oxcarbazepine that resulted were within the therapeutic ranges. TDM results of darunavir measured in these patients were comparable with values usually measured in the control group. Conversely, the trough concentrations for atazanavir and dolutegravir demonstrated significantly lower values when compared with values usually measured in HIV-infected patients not treated with antiepileptic drugs (190 ± 91 versus 546 ± 380 ng/mL; -65%, P < 0.001; 191 ± 78 versus 1096 ± 510 ng/mL; -83%, P < 0.001, respectively).

CONCLUSIONS

Co-administration of carbamazepine or oxcarbazepine with atazanavir or dolutegravir should be avoided owing to the potential risk of virological failure; in case of these 2 drugs, the adoption of TDM is strongly advisable, eventually combining with increased antiretroviral doses.

Impact of Therapeutic Drug Monitoring of Antiretroviral Drugs in Routine Clinical Management of People Living With HIV: A Narrative Review

BACKGROUND

The treatment of HIV infection has evolved significantly since the advent of highly active antiretroviral therapy. As a result, a response rate of 90%-95% now represents a realistically achievable target. Given this background, it is difficult to imagine the additional benefits that therapeutic drug monitoring (TDM) could provide in the management of HIV infection.

METHODS

This article is not intended to provide a systematic literature review on TDM of antiretroviral agents; rather, the authors aim to discuss the potential added value of TDM in the optimal management of people living with HIV (PLWH) in selected real-life clinical scenarios based on data collected over 10 years by their TDM service.

RESULTS

Some clinical situations, in which the selection of the optimal antiretroviral therapy is challenging, have been identified. These include poorly compliant patients, suboptimal antiretroviral therapies (in terms of both efficacy and toxicity), polypharmacy with a high risk of drug-drug interactions, and different patient populations, such as pregnant women.

CONCLUSIONS

The transformation of HIV infection from a near-universally fatal illness to a lifelong chronic disease has resulted in an HIV population that is growing and aging, placing new and increasing demands on public programs and health services. Increasingly, the management of comorbidities, polypharmacy, and drug-drug interaction, and their impact on antiretroviral therapy will have to be undertaken. These clinical settings represent some of the new frontiers for the use of TDM with the goal of achieving optimal prescription and outcome for PLWH.

Concomitant Use of Cotrimoxazole and Atazanavir in HIV-infected Patients: A Therapeutic Drug Monitoring and Pharmacovigilance Based Dual Approach

BACKGROUND

Cotrimoxazole is the main antibiotic used in primary prophylaxis for opportunistic infections in advanced HIV infection. This drug can inhibit one of the metabolic pathways of atazanavir (ATV), such as the cytochromes P450 (CYP) 2C8/2C9 and could interfere with its safety and efficacy.

OBJECTIVE

We studied the drug-drug interaction (DDI) between cotrimoxazole and ATV by using therapeutic drug monitoring (TDM) and pharmacovigilance (PV) approaches.

METHODS

We compared a group of patients treated with cotrimoxazole and receiving an ATV-based regimen to controls. This historical cohort analysis used data from Dat'AIDS in HIV-infected patients who had at least two lowest plasma concentrations (C-trough) of ATV during their outpatient follow-up. Likewise, we used the international pharmacovigilance data from VigiBase to evaluate the notifications of hyperbilirubinemia reported with ATV.

RESULTS

In the TDM analysis, the two groups of patients (treated with cotrimoxazole and controls) were almost homogeneous concerning the main baseline features. After at least six months of ATVbased regimen, there was no significant difference in the safety threshold of the ATV C-trough [with an adjusted odds ratio (aOR) of 1.4 (95% CI: 0.5 - 4.4)] compared to controls. We observed similar results with the efficacy thresholds of ATV C-trough. Regarding the PV analysis, there was no difference in hyperbilirubinemia occurring with ATV when cotrimoxazole was concomitant, with an adjusted reporting odds ratio (aROR) of 0.9 (95% CI: 0.6 to 1.2).

CONCLUSION

This study showed a relevant concomitant use between Cotrimoxazole and ATV based on TDM and PV approaches.

The Changing Face of Human Immunodeficiency Virus-Mediated Kidney Disease

In nearly 40 years since human immunodeficiency virus (HIV) first emerged, much has changed. Our understanding of the pathogenesis of HIV infection and its effect on the cells within each kidney compartment has progressed, and the natural history of the disease has been transformed. What was once an acutely fatal illness is now a chronic disease managed with oral medications. This change is largely due to the advent of antiretroviral drugs, which have dramatically altered the prognosis and progression of HIV infection. However, the success of antiretroviral therapy has brought with it new challenges for the nephrologist caring for patients with HIV/acquired immune deficiency syndrome, including antiretroviral therapy-induced nephrotoxicity, development of non-HIV chronic kidney disease, and rising incidence of immune-mediated kidney injury. In this review, we discuss the pathogenesis of HIV infection and how it causes pathologic changes in the kidney, review the nephrotoxic effects of select antiretroviral medications, and touch upon other causes of kidney injury in HIV cases, including mechanisms of acute kidney injury, HIV-related immune complex glomerular disease, and thrombotic microangiopathy.

Adverse effects of chronic treatment with the Main subclasses of highly active antiretroviral therapy: a systematic review

OBJECTIVES

The aim of the review was to elucidate the adverse effects of chronic treatment with the main subclasses of highly active antiretroviral therapy (HAART).

METHODS

A systematic review was carried out using the methods recommended in the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols (PRISMA-P). Searches of articles in MEDLINE, SCIELO, Web of Science and LILACS were conducted from January to October 2018 based on the following descriptors and keywords: 'HIV' [AND]; 'AIDS' [OR]; 'HAART' [AND]; 'Highly Active Antiretroviral Therapy' [OR]; 'Adverse Effects' [AND]. All articles selected described the biochemical changes produced by, and the main adverse effects of, using one or more of the following HAART subclasses: nucleoside reverse transcriptase inhibitors (NRTIs), nonnucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs) and other new drugs. The selected articles included patients living with HIV (PLWH) initiating or continuing any type of HAART. The results are presented qualitatively and discussed.

RESULTS

Twenty-one articles found in the searches were selected for the review, and they included a total of 5626 participants. Seven of the studies investigated mainly NRTIs, three studies mainly NNRTIs, eight studies predominantly PIs, and three studies other antiretroviral drugs as the main treatment. The most common adverse effects on biochemical parameters were the emergence of anaemia for NRTIs as well as NNRTIs and PIs, and plasma lipid alterations caused by their prolonged use. In general, it was found that biological differences among individuals can cause differences in adverse effects, such as virological and treatment failure.

CONCLUSIONS

One or more occurrences of adverse effects of the chronic utilization of drugs were found for all subclasses of HAART, and certain combinations of drugs from different subclasses were also found to be associated with adverse events.

Long-term kidney function, proteinuria, and associated risks among HIV-infected and uninfected men

BACKGROUND

Factors affecting kidney function and proteinuria among HIV-positive (HIV+) and HIV-negative (HIV-) persons need better characterization.

METHODS

We evaluated estimated glomerular filtration rate (eGFR, ml/min per 1.73 m) changes, proteinuria prevalence (a urine protein-to-creatinine ratio of ≥0.2 at two consecutive visits) and associated factors among HIV+ and HIV- men.

RESULTS

There were 917 HIV+ men receiving HAART, 159 HIV+ men not receiving HAART, and 1305 HIV- men seen from October 2003 to September 2014. Median annual eGFR change was -0.5, -0.8% for HIV+ and -0.3% for HIV- men (P < 0.001). Factors significantly (P < 0.05) associated with more than 3% annual eGFR decline were HAART receipt (but no specific antiretroviral drug), age more than 50, hypertension, diabetes, current smoking. Proteinuria existed in 14.9% of visit-pairs among HAART recipients, 5.8% among non-HAART recipients, and 1.9% among HIV- men, and was associated with subsequent annual more than 3% eGFR decline (odds ratio 1.80, P < 0.001). Proteinuria-associated factors also included HAART use (vs. HIV-), age at least 50 (vs. <40), diabetes, hypertension, current smoking, hepatitis C virus-infection (all P < 0.05) and, among HIV+ men, lower CD4 cell count, didanosine, saquinavir, or nelfinavir use (all P < 0.05). After adjusting for proteinuria, among HAART users, having a detectable HIV RNA, cumulative use of tenofovir disoproxil fumarate, emtricitabine, ritonavir, atazanavir, any protease inhibitor, or fluconazole were associated with more than 3% annual eGFR decline.

CONCLUSION

Longitudinal kidney function decline was associated with HAART use but no individual antiretroviral drug, and traditional kidney disease risks. Proteinuria was nearly seven times more common in HAART-treated men than HIV- men, reflected recent eGFR decline and predicted subsequent eGFR decline.

Novel Antiretroviral Drugs in Patients with Renal Impairment: Clinical and Pharmacokinetic Considerations

Highly active antiretroviral therapy (HAART) has dramatically increased the survival of HIV-infected patients from Western countries reducing the incidence of opportunistic infections and AIDS-related malignancies, and improving the patients' quality of life compared with the pre-HAART era. HIV is thus now considered in the West as a chronic disease, with the majority of HIV-infected patients successfully reaching an optimal immune and virological outcome a few months after starting HAART. However, this switch from acute to chronic disease has been accompanied by an increased incidence of chronic kidney disease (CKD), reported in up to 60% of HIV-infected patients. Tenofovir disoproxil fumarate (TDF) is considered to play a significant role in the development of CKD in these patients. It has been proposed that tenofovir alafenamide (TAF), a prodrug formulation able to providing lower systemic and renal drug exposure, could potentially contribute to reduce the development of CKD in HAART-treated patients. On the other hand, the pharmacokinetics of some components of HAART can be significantly altered in HIV-infected patients developing CKD. TDF- or TAF-based antiretroviral regimens should be avoided in patients with a creatinine clearance of less than 50 or 30 mL/min, respectively. This review focuses on the pharmacokinetic changes of novel antiretroviral drugs in HIV-infected patients with renal impairment or requiring renal replacement therapy, and provides some suggestions on how to change drug doses in these clinical settings.

Development and validation of an assay to analyze atazanavir in human hair via liquid chromatography/tandem mass spectrometry

RATIONALE

Assays to quantify antiretrovirals in hair samples are increasingly used to monitor adherence and exposure in both HIV prevention and treatment studies. Atazanavir (ATV) is a protease inhibitor used in combination antiretroviral therapy (ART). We developed and validated a liquid chromatography/tandem mass spectrometry (LC/MS/MS)-based method to quantify ATV in human hair, per the NIH Division of AIDS Clinical Pharmacology Quality Assurance (CPQA) program and the FDA bioanalytical method validation guidelines.

METHODS

ATV was extracted from hair using optimized methods and the extracts were injected onto a BDS C-18 column (5 μm, 4.6 × 100 mm), followed by isocratic elution via a mobile phase composed of 55% acetonitrile, 45% water, 0.15% acetic acid, and 4 mM ammonium acetate, at a flow rate of 0.8 mL/min prior to analysis by MS/MS. Levels were quantified using positive electrospray ionization by multiple reaction monitoring (MRM) for the transitions MH⁺ m/z 705.3 to m/z 168.0 and MH⁺ m/z 710.2 to m/z 168.0 for ATV and ATV-d5 (internal standard), respectively.

RESULTS

Our assay demonstrated a linear standard curve (r = 0.99) over the concentration range of 0.0500 ng ATV/mg hair to 20.0 ng/mg hair. The inter- and intraday accuracy of ATV quality control (QC) samples was -1.33 to 4.00% and precision (% coefficient of variation (%CV)) was 1.75 to 6.31%. The %CV for ATV levels in hair samples from highly adherent patients (incurred samples) was less than 10%. No significant endogenous peaks or crosstalk were observed in the specificity test with other HIV drugs. The overall extraction efficiency of ATV from incurred hair samples was greater than 95%.

CONCLUSIONS

This highly sensitive, highly specific and validated assay can be considered for therapeutic drug monitoring for HIV-infected patients on ATV-based ART.

Antiretroviral Drug Metabolism in Humanized PXR-CAR-CYP3A-NOG Mice

Antiretroviral drug (ARV) metabolism is linked largely to hepatic cytochrome P450 activity. One ARV drug class known to be metabolized by intestinal and hepatic CYP3A are the protease inhibitors (PIs). Plasma drug concentrations are boosted by CYP3A inhibitors such as cobisistat and ritonavir (RTV). Studies of such drug-drug interactions are limited since the enzyme pathways are human specific. While immune-deficient mice reconstituted with human cells are an excellent model to study ARVs during human immunodeficiency virus type 1 (HIV-1) infection, they cannot reflect human drug metabolism. Thus, we created a mouse strain with the human pregnane X receptor, constitutive androstane receptor, and CYP3A4/7 genes on a NOD.Cg-Prkdc^scid Il2rg^tm1Sug/JicTac background (hCYP3A-NOG) and used them to evaluate the impact of human CYP3A metabolism on ARV pharmacokinetics. In proof-of-concept studies we used nanoformulated atazanavir (nanoATV) with or without RTV. NOG and hCYP3A-NOG mice were treated weekly with 50 mg/kg nanoATV alone or boosted with nanoformulated ritonavir (nanoATV/r). Plasma was collected weekly and liver was collected at 28 days post-treatment. Plasma and liver atazanavir (ATV) concentrations in nanoATV/r-treated hCYP3A-NOG mice were 2- to 4-fold higher than in replicate NOG mice. RTV enhanced plasma and liver ATV concentrations 3-fold in hCYP3A-NOG mice and 1.7-fold in NOG mice. The results indicate that human CYP3A-mediated drug metabolism is reduced compared with mouse and that RTV differentially affects human gene activity. These differences can affect responses to PIs in humanized mouse models of HIV-1 infection. Importantly, hCYP3A-NOG mice reconstituted with human immune cells can be used for bench-to-bedside translation.

Severe Hyperbilirubinemia in an HIV-HCV-Coinfected Patient Starting the 3D Regimen That Resolved After TDM-Guided Atazanavir Dose Reduction

The combination of ombitasvir, dasabuvir, and paritaprevir/ritonavir (considered as the 3D regimen) has proven to be associated with high sustained virologic response and optimal tolerability in hepatitis C virus-infected patients. Here, we describe an HIV-HCV-coinfected patient who experienced a grade 4 hyperbilirubinemia and a 2.5-fold increase in the atazanavir plasma trough concentrations few days after the start of 3D-based antiviral therapy who benefited from an atazanavir dose reduction guided by therapeutic drug monitoring.

Kidney Disease in HIV: Moving beyond HIV-Associated Nephropathy

In developed countries, remarkable advances in antiretroviral therapy have transformed HIV infection into a chronic condition. As a result, HIV-associated nephropathy, the classic HIV-driven kidney lesion among individuals of African descent, has largely disappeared in these regions. However, HIV-positive blacks continue to have much higher rates of ESRD than HIV-positive whites, which could be attributed to the APOL1 renal risk variants. Additionally, HIV-positive individuals face adverse consequences beyond HIV itself, including traditional risk factors for CKD and nephrotoxic effects of antiretroviral therapy. Concerns for nephrotoxicity also extend to HIV-negative individuals using tenofovir disoproxil fumarate-based pre-exposure prophylaxis for the prevention of HIV infection. Therefore, CKD remains an important comorbid condition in the HIV-positive population and an emerging concern among HIV-negative persons receiving pre-exposure prophylaxis. With the improved longevity of HIV-positive individuals, a kidney transplant has become a viable option for many who have progressed to ESRD. Herein, we review the growing knowledge regarding the APOL1 renal risk variants in the context of HIV infection, antiretroviral therapy-related nephrotoxicity, and developments in kidney transplantation among HIV-positive individuals.

Ureteral Obstruction Due to Radiolucent Atazanavir Ureteral Stones

Background: Protease inhibitors (PIs) are a well-documented cause of nephrolithiasis. Although medications such as indinavir are known to increase risk of stone formation, the association of newer HIV medications is not as well studied. In this study, we report a case of a patient who developed atazanavir stones.

Case Presentation: A 74-year-old man with HIV on antiretroviral therapy—including atazanavir, a PI—presented with right flank pain. He previously had passed two ureteral stones that were not analyzed. A CT scan showed mild right hydronephrosis without evidence of nephrolithiasis or ureteral obstruction. The patient was presumed to have passed a stone and was discharged home. He returned one day later with persistent flank pain and acute kidney injury that did not improve with intravenous fluid hydration. A right ureteral stent was placed that relieved his symptoms. Subsequent ureteroscopy demonstrated bilateral ureteral stones that were basket extracted. Stone composition was 100% atazanavir. Since being switched off of this medication, the patient has not had any further episodes of renal colic and his renal function has improved to below his baseline level on presentation.

Conclusion: Patients treated with the PI atazanavir are at risk for developing nephrolithiasis and obstructive uropathy. Because these stones can be radiolucent on CT scan, a high level of suspicion is required to accurately diagnose ureteral obstruction in these patients. Alternative effective HIV treatment regimens can to be utilized when clinically indicated.

HIV and kidney diseases: 35 years of history and consequences

Kidney diseases in human immunodeficiency virus (HIV)-infected patients are often misdiagnosed. Despite reductions in morbidity and mortality owing to widespread use of highly effective combination antiretroviral therapy (cART), acute kidney injury (AKI) and chronic kidney disease (CKD) are still more common in these patients than in the general population, and are associated with poor health outcomes. HIV-associated nephropathy and HIV immune complex kidney diseases are the more recognizable HIV-related kidney diseases. However, a broad spectrum of kidney disorders related or not directly related with HIV infection can be observed, including cART-induced AKI, CKD, proximal tubular dysfunction, crystalluria and urolithiasis, among others. This review summarizes the major epidemiologic studies of kidney diseases in HIV-infected patients, discusses novel approaches that may potentially limit nephrotoxicity such as the use of tenofovir alafenamide, and outlines current screening measures for early diagnosis of kidney dysfunction or tubular damage, and for accurate detection of increased risk for acute or chronic kidney diseases.

Is the unbound concentration of atazanavir of interest in therapeutic drug monitoring?

To date, therapeutic drug monitoring (TDM) is carried out with antiretrovirals and is usually based on total concentrations (C_t ). However, for some patients, TDM does not reflect efficacy or the avoidance of toxicity as is the case for atazanavir (ATV), a HIV protease inhibitor. As the unbound concentration (C_u ) is the pharmacological active form, the aim of the study was to evaluate the value of C_u and the unbound fraction (f_u , f_u = C_u /C_t ) for the TDM of ATV. The variability of C_u and the corresponding f_u of ATV was explored in 43 patients treated with ATV for an average of 13.5 months. C_u was determined by coupling ultrafiltration and liquid chromatography. As ATV is highly bound to alpha-1 acid glycoprotein (AAG), the correlation between f_u and AAG was also evaluated. The viral load was monitored to evaluate the patients' virologic response, while total plasma bilirubin and unconjugated plasma bilirubin were used as biomarkers of ATV toxicity. Median trough C_u and C_t were 37.9 μg/L (Interquartile range (IQR) 20.6-94.9 μg/L) and 628.6 μg/L (IQR 362.7-1078.1 μg/L), respectively. f_u , C_u and C_t showed high variability, but the f_u variability was not correlated with the AAG level. The unbound concentration and fraction were unrelated to the virologic response (P = 0.21 and P = 0.65 for C_u and f_u , respectively) nor to the unconjugated bilirubin (Pearson correlation coefficient (ρ), ρ = 0.22; P = 0.17 for C_u ). Neither total nor unbound concentrations of ATV fully explained hyperbilirubinaemia or virologic failure. From this study, we conclude that unbound ATV did not appear to be more relevant than C_t .

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

For many patients living with HIV-1, the efficacy of combined ART (cART) has made the infection turn to a chronic disease. Because cART is associated with a risk of long-term toxicity, switching patients with virological success to another therapy remains a major issue. Studies undertaken and published over recent years have shown that switching patients exhibiting virological suppression to less-drug regimens (LDR) is a possible option of maintenance strategy. The use of ritonavir-boosted PIs (PI/r) as the backbone of LDR-based maintenance therapy is consistent with their virological potency and a high genetic barrier of resistance. Atazanavir is the most documented PI/r regarding maintenance in dual therapy, with favourable results in terms of virological suppression, tolerance improvement and absence of emergence of mutations. Furthermore, atazanavir is the only commonly prescribed PI that can be used after withdrawal of ritonavir, with maintenance of virological suppression whatever the backbone of associated NRTIs. Based on clinical studies, and taking into account the characteristics of the patients included, one may consider that for any patient with a virological suppression on cART for at least 12 months, with the nadir CD4 >100 cells/mm³ and an absence of encephalitis, an LDR-based maintenance therapy including atazanavir can be considered. Cumulative genotypes must be available to make sure that the LDR will not jeopardize future therapeutic options. The final decision regarding the most appropriate LDR must be guided by the objectives shared by the physician and his/her patient.

Factors involved in continuance of atazanavir-based regimens: Results from a cohort of HIV1-positive patients

We evaluated predictive factors involved in durability and therapeutic failure of atazanavir (ATV)-based antiretroviral regimens with or without ritonavir (r) in real life setting. This retrospective study of HIV-1-positive patients evaluated the factors related to ATV continuance and the time-dependent probability of therapeutic failure (HIV-RNA >200 copies/mL and concomitant discontinuation of ATV). We also investigated the rate of therapeutic failure and the variations in total bilirubin levels from starting unboosted ATV-based regimens. The study involved 1030 patients: 183 treatment-naïve patients (17.8%) started ATV/r (17 subsequently switched to unboosted ATV); 653 (63.4%) switched to ATV/r from previous antiretroviral regimens (121 subsequently switched to unboosted ATV); and 194 (18.8%) switched to unboosted ATV from previous ATV-free regimens. The median ATV follow-up was 28 months (interquartile range 7-56). The risk of ATV discontinuation was significantly lower in patients switched to unboosted ATV from ATV/r (HR 0.45; p < 0.0001). The discontinuation of ATV correlated with female gender (HR 1.26; p = 0.035), use of a zidovudine/didanosine/stavudine containing backbone (HR 1.8; p = 0.004), and a baseline CD4+ cell counts of <200/μL (HR 1.54; p = 0.003), the last of which was also associated with a higher risk of therapeutic failure (HR 2.42; p = 0.001). Total bilirubin levels were significantly lower in the patients switching from ATV/r to unboosted ATV. Unboosted ATV-based therapies are safe and effective options in patients whose immuno-virological conditions are stable, and allow the long-term survival of ATV-containing regimens.