Efficacy and safety of boosted and unboosted atazanavir-containing antiretroviral regimens in real life: results from a multicentre cohort study

Incident diabetes in course of antiretroviral therapy

OBJECTIVE

Recent reports of excessive weight gain in people with HIV (PWH) have raised increasing concerns on the possible increase of diabetes mellitus (DM) risk in course of integrase inhibitors (INSTIs) treatment. In this study, we aimed at describing DM incidence in course of antiretroviral therapy (ART) and identifying the factors associated with new DM onset.

DESIGN

Observational prospective SCOLTA (Surveillance Cohort Long-Term Toxicity Antiretrovirals) cohort.

METHODS

All people enrolled in SCOLTA between January 2003 and November 2021 were included. Multivariable Cox regression yielded adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for incident DM.

RESULTS

4366 PWH were included, 72.6% male, with mean age 45.6 years, and median CD4 + 460 [interquartile range (IQR) 256-710] cells/mm 3 cells/mm 3 . During the follow up, 120 incident cases of DM occurred (1.26 cases/100 person year-follow up, 95% CI 1.05-1.50).Baseline weight, but not the amount of weight gain, resulted significantly correlated to diabetes incidence (aHR by 1 kg 1.03; 95% CI 1.01-1.04), as well as older age (aHR 1.03 by 1 year; 95% CI 1.01-1.06), being ART-experienced with detectable HIV RNA at study entry (aHR 2.27, 95% CI 1.48-3.49), having untreated high blood pressure (aHR 2.90; 95% CI 1.30-6.45) and baseline blood glucose >100 mg/dl (aHR 5.47; 95% CI 3.82-7.85). Neither the INSTI class nor individual antiretrovirals were associated with an increased risk of DM.

CONCLUSIONS

Baseline weight, but not weight gain or the ART class, was associated with incident DM in this observational cohort.

Pd(II) Complexes of Chiral Proline-Derived Ligands: Application for Dynamic Thermodynamic Resolution of α-Amino Acids and Their Antibacterial Activities

Novel type of Pd(II) complexes have been synthesized under operationally simple and convenient conditions and applied in the dynamic thermodynamic resolution of racemic N,C-unprotected α-amino acids. After rapid hydrolysis, these Pd(II) complexes produced the corresponding α-amino acids in satisfactory yields and enantioselectivities, accompanied by the recyclable proline-derived ligand. In addition, the method can be readily applied for S/R interconversion to obtain unnatural (R)-α-amino acids from readily available (S)-α-amino acids. Furthermore, biological assays showed that Pd(II) complexes (S,S)-3i and (S,S)-3m exhibited significant antibacterial activities similar to vancomycin, which may represent promising lead structures for further development of antibacterial agents.

Reversibility of Central Nervous System Adverse Events in Course of Art

The purpose of this study is to evaluate the frequency of central nervous system adverse events (CNS-AE) on dolutegravir (DTG) and non-DTG containing ART, and their reversibility, in the observational prospective SCOLTA cohort. Factors associated with CNS-AE were estimated using a Cox proportional-hazards model. 4939 people living with HIV (PLWH) were enrolled in DTG (n = 1179) and non-DTG (n = 3760) cohorts. Sixty-six SNC-AE leading to ART discontinuation were reported, 39/1179 (3.3%) in DTG and 27/3760 (0.7%) in non-DTG cohort. PLWH naïve to ART, with higher CD4 + T count and with psychiatric disorders were more likely to develop a CNS-AE. The risk was lower in non-DTG than DTG-cohort (aHR 0.33, 95% CI 0.19−0.55, p < 0.0001). One-year follow-up was available for 63/66 PLWH with CNS-AE. AE resolution was reported in 35/39 and 23/24 cases in DTG and non-DTG cohorts, respectively. The probability of AE reversibility was not different based on ART class, sex, ethnicity, CDC stage, or baseline psychiatric disorder. At the same time, a lower rate of event resolution was found in PLWH older than 50 years (p = 0.017). In conclusion, CNS-AE leading to ART discontinuation was more frequent in DTG than non-DTG treated PLWH. Most CNS-AE resolved after ART switch, similarly in both DTG and non-DTG cohorts.

Serum Lipid Profiles of Patients Taking Efavirenz-Based Antiretroviral Regimen Compared to Ritonavir-Boosted Atazanavir with an Optimized Background at Zewditu Memorial Hospital, Addis Ababa, Ethiopia

Background

Dyslipidemia represents significant health care concerns in patients taking antiretroviral therapy due to their association with cardiovascular disease risk. There is limited data regarding the effects of boosted atazanavir (ATV/r) treatment in the lipid profiles of Ethiopian HIV patients. Thus, this study compares the mean values of lipid profile differences of HIV patients on ATV/r-based regimen compared to efavirenz (EFV)-based regimen, while the background is Tenofovir Disoproxil Fumarate/lamivudine.

Materials and Methods

A comparative hospital-based cross-sectional study was conducted among adult HIV-infected patients at Zewditu Memorial Hospital, Addis Ababa, Ethiopia, from July–September 2017. An equal number of EFV and ATV/r-treated patients (n=90 each) receiving for 1-year and over were included in the study. Serum total cholesterol (TC), triglyceride (TG), gigh-density lipoprotein cholesterol (HDL-c), and low-density lipoprotein cholesterol (LDL-c) were measured. Data comparison used chi-square test, Student’s t-test and Mann–Whitney U-test. Multivariate logistic regression analysis and p-value<0.05 were used to identify associated factors of serum lipid profiles.

Results

In the present study, the ATV/r-treated group results were significantly higher in the median values of TG [207 (56–1094) vs 145 (42–768) mg/dL; p=0.001] and the mean value of TG/HDL-c (6.6 vs 4.4; p=0.001) as compared to the EFV-treated group. The EFV-treated group showed significantly higher in the mean value of HDL-c (44.7 vs 38.7 mg/dL; p=0.001) as compared to the ATV/r-treated group. Body mass index was associate with LDL and HDL. CD4 was associated with TC. Current antiretroviral therapy was associated with TG. Duration of HIV since first diagnosis and duration of ART were associated with HDL.

Conclusion

ATV/r is associated with elevated in TG and TG/HDL-C, but low HDL as compared to EFV. Differences in LDL or HDL that were found were of unclear clinical significance. The long-term significance is unknown.

Discontinuation of dolutegravir, elvitegravir/cobicistat and raltegravir because of toxicity in a prospective cohort

OBJECTIVES

The aim of the study was to assess the rates of discontinuation of integrase inhibitor regimens because of any neuropsychiatric adverse event (NPAE) and the factors associated with discontinuation.

METHODS

A population-based, prospective, multicentre cohort study was carried out. Treatment-naïve subjects starting therapy with a regimen containing integrase inhibitors, or those switching to such a regimen, with plasma HIV-1 RNA < 50 HIV-1 RNA copies/mL in 14 hospitals in Catalonia or the Balearic Islands (Spain) were included in the study. Every discontinuation because of adverse events (AEs) was double-checked directly with treating physicians. Multivariable Cox models identified factors correlated with discontinuation.

RESULTS

A total of 4165 subjects (37% treatment-naïve) started regimens containing dolutegravir (n = 1650; 91% with abacavir), raltegravir (n = 930) or elvitegravir/cobicistat (n = 1585). There were no significant differences among regimens in the rate of discontinuation because of any AE. Rates of discontinuation because of NPAEs were low but higher for dolutegravir/abacavir/lamivudine [2.1%; 2.9 (95% confidence interval (CI) 2.0, 4.2) discontinuations/100 patients/year] versus elvitegravir/cobicistat (0.5%; 0.8 (95% CI 0.3, 1.5) discontinuations/100 patients/year], with significant differences among centres for dolutegravir/abacavir/lamivudine and NPAEs (P = 0.003). We identified an association of female gender and lower CD4 count with increased risk of discontinuation because of any AE [Incidence ratio (IR) 2.3 (95% CI 1.4, 4.0) and 1.8 (95% CI 1.1, 2.8), respectively]. Female gender, age > 60 years and abacavir use were not associated with NPAE discontinuations. NPAEs were commonly grade 1-2, and had been present before and improved after drug withdrawal.

CONCLUSIONS

In this large prospective cohort study, patients receiving dolutegravir, raltegravir or elvitegravir/cobicistat did not show significant differences in the rate of discontinuation because of any toxicity. The rate of discontinuations because of NPAEs was low, but was significantly higher for dolutegravir than for elvitegravir/cobicistat, with significant differences among centres, suggesting that greater predisposition to believe that a given adverse event is caused by a given drug of some treating physicians might play a role in the discordance seen between cohorts.

Role of systemic inflammation scores for prediction of clinical outcomes in patients treated with atazanavir not boosted by ritonavir in the Italian MASTER cohort

Background

Atazanavir (ATV) not boosted by ritonavir (uATV) has been frequently used in the past for switching combination antiretroviral therapy (cART). However, the clinical outcomes and predictors of such strategy are unknown.

Methods

An observational study was carried out on the Italian MASTER, selecting HIV infected patients on cART switching to an uATV-containing regimen. Baseline was set as the last visit before uATV initiation. In the primary analysis, a composite clinical end-point was defined as the first occurring of any condition among: liver, cardiovascular, kidney, diabetes, non AIDS related cancer or death events. Incidence of AIDS events and incidence of composite clinical end-point were estimated. Kaplan-Meier and multivariable Cox regression analysis were used to assess predictors of the composite clinical end-point.

Results

436 patients were observed. The majority of patients were males (61.5%) and Italians (85.3%), mean age was 42.7 years (IQR: 37.7–42), the most frequent route of transmission was heterosexual intercourse (47%), followed by injection drug use (25%) and homosexual contact (24%); the rate of HCV-Ab positivity was 16.3%. Patients were observed for a median time of 882 days (IQR: 252-1,769) under uATV. We recorded 93 clinical events (3 cardiovascular events, 20 kidney diseases, 33 liver diseases, 9 non AIDS related cancers, 21 diabetes, 7 AIDS events), and 19 deaths, accounting for an incidence of 3.7 (composite) events per 100 PYFU. At multivariable analysis, factors associated with the composite clinical end-point were intravenous drug use as risk factor for HIV acquisition vs. heterosexual intercourses [HR: 2.608, 95% CI 1.31–5.19, p = 0.0063], HIV RNA per Log₁₀ copies/ml higher [HR: 1.612, 95% CI 1.278–2.034, p < 0.0001], number of switches in the nucleoside/nucleotide (NRTI) backbone of cART (performed to compose the uATV regimen under study or occurred in the past) per each more [HR: 1.085, 95% CI 1.025–1.15, p = 0.0051], Fib-4 score per unit higher [HR: 1.03, 95% CI 1.018–1.043, p < 0.0001] and Neutrophil/lymphocytes ratio (NLR inflammation score) per Log₁₀ higher [HR: 1.319, 95% CI 1.047–1.662, p = 0.0188].

Conclusions

Intravenous drug users with high HIV RNA, high Fib-4 levels and more heavily exposed to antiretroviral drugs appeared to be more at risk of clinical events. Interestingly, high levels of inflammation measured through NLR, were also associated with clinical events. So, these patients should be monitored more strictly.

Efficacy, safety and pharmacokinetics of atazanavir (200mg twice daily) plus raltegravir (400mg twice daily) dual regimen in the clinical setting

BACKGROUND

Unboosted atazanavir with raltegravir has been investigated at 300mg twice daily showing frequent hyperbilirubinemia and selection of resistance-associated mutations.

OBJECTIVES

Atazanavir 200mg twice daily could increase tolerability and plasma exposure.

STUDY DESIGN

Patients on atazanavir/raltegravir (200/400 twice daily), with self-reported adherence >95% and no concomitant interacting drugs were retrospectively evaluated.

RESULTS

102 patients [72.5% male, age 46.4 years (42-54), BMI 24kg/m² (22-26)] were included. CD4+ T lymphocytes were 417 cell/μL (302-704) and 76 patients (74.5%) had HIV-RNA <50 copies/ml. After 123 weeks 18.6% patients showed virological failure and 3.9% discontinued for intolerance. Available genotypes showed selection of major integrase (7/10 patients) and protease resistance-associated mutations (5/13 patients). In patients switching with dyslipidemia (n=67) total, LDL cholesterol and triglycerides significantly decreased. Patients switching with eCRCL<60ml/min (n=27) had no significant changes while patients with eCRCL >60ml/min showed significant decrease (-9.8ml/min, p=0.003) at 96-weeks. Atazanavir and raltegravir trough concentrations were 321ng/mL (147-720) and 412ng/mL (225-695). Self-reported non-adherence (n=4) was significantly associated with virological failure (p=0.02); patients with virological success had borderline longer previous virological control (33 vs. 18 months, p=0.07).

DISCUSSION

Switch to atazanavir/raltegravir was safe and well tolerated allowing optimal drugs' plasma exposure. However, a concerning rate (18.6%) failed with newly selected mutations and stopped ATV/RAL because of DDI and intolerance issues or were lost to follow-up. This regimen might be considered in selected patients, without history of protease inhibitors failure or HBV infection, showing optimal adherence and prolonged suppression.

Long-term effectiveness of unboosted atazanavir plus abacavir/lamivudine in subjects with virological suppression: A prospective cohort study

Effectiveness data of an unboosted atazanavir (ATV) with abacavir/lamivudine (ABC/3TC) switch strategy in clinical routine are scant.We evaluated treatment outcomes of ATV + ABC/3TC in pretreated subjects in the EuroSIDA cohort when started with undetectable plasma HIV-1 viral load (pVL), performing a time to loss of virological response (TLOVR <50 copies/mL) and a snapshot analysis at 48, 96, and 144 weeks. Virological failure (VF) was defined as confirmed pVL >50 copies/mL.We included 285 subjects, 67% male, with median baseline CD4 530 cells, and 44 months with pVL ≤50 copies/mL. The third drug in the previous regimen was ritonavir-boosted atazanavir (ATV/r) in 79 (28%), and another ritonavir-boosted protease inhibitor (PI/r) in 29 (10%). Ninety (32%) had previously failed with a PI. Proportions of people with virological success at 48/96/144 weeks were 90%/87%/88% (TLOVR) and 74%/67%/59% (snapshot analysis), respectively. The rates of VF were 8%/8%/6%. Rates of adverse events leading to study discontinuation were 0.4%/1%/2%. The multivariable adjusted analysis showed an association between VF and nadir CD4+ (hazard ratio [HR] 0.63 [95% confidence interval [CI]: 0.42-0.93] per 100 cells higher), time with pVL ≤50 copies/mL (HR 0.87 [95% CI: 0.79-0.96] per 6 months longer), and previous failure with a PI (HR 2.78 [95% CI: 1.28-6.04]). Resistance selection at failure was uncommon.A switch to ATV + ABC/3TC in selected subjects with suppressed viremia was associated with low rates of VF and discontinuation due to adverse events, even in subjects not receiving ATV/r. The strategy might be considered in those with long-term suppression and no prior PI failure.

Four days a week or less on appropriate anti-HIV drug combinations provided long-term optimal maintenance in 94 patients: the ICCARRE project

Short, intraweekly cycles of anti-HIV combinations have provided intermittent, effective therapy (on 48 patients) (1). The concept is now extended to 94 patients on treatment, 4 days per week or less, over a median of 2.7 discontinuous treatment years per patient. On suppressive combinations, 94 patients volunteered to treatment, 5 and 4 days per week, or reduced stepwise to 4, 3, 2, and 1 days per week in 94, 84, 66, and 12 patients, respectively, on various triple, standard, antiviral combinations, or nonregistered, quadruple, antiviral combinations. Ninety-four patients on treatment 4 days per week aggregated 165 intermittent treatment years; no viral breakthrough was observed over 87 average treatment weeks per patient, 63 of 94 having passed 2.5 intermittent treatment years on any of the antiviral combinations prescribed. On the hyperintermittent treatment of 3, 2, and 1 days per week, HIV RNA surged >50 copies, 4 weeks apart, in 18 instances (6.8 viral escapes/100 hyperdiscontinuous maintenance years). Viral escapes could have been a result of erratic adherence (EA) to regimen or follow-up (3 patients)--drug taken at half of the daily recommended dosage (8 patients) and/or overlooked archival-resistant HIVs from antecedent treatment failures (6 patients). Aside from the above circumstances, HIV unexpectedly rebounded in 3 patients on 2 days per week treatment and 1 patient on 1 day per week treatment, posting 2.2 intrinsic viral escapes/100 highly discontinuous treatment years. All 18 escapes were eventually reversed by 7 days per week salvage combinations, and 11 of 18 patients have been back for a second course of intermittent therapy, 4 days per week or less. Both cell-activation markers on the surface of T lymphocytes and cell-bound HIV DNA levels remained stable or declined. CD4/CD8 ratios rose to ≥1 in 35% of patients, whereas CD4 counts went ≥500/µl in 75%. These values were previously 7 and 40%, respectively, on 7 days per week therapy. In our aging, long, HIV-enduring, multitreated patient cohort, treatment 4 days per week and less over 421 intermittent treatment years reduced prescription medicines by 60%--equivalent to 3 drug-free/3 virus-free remission year per patient--actually sparing €3 million on just 94 patients at the cost of 2.2 intrinsic viral failure/100 hyperintermittent treatment years. At no risk of viral escape, maintenance therapy, 4 days per week, would quasiuniversally offer 40% cuts off of current overprescriptions.

Gender differences in HIV infection: is there a problem? Analysis from the SCOLTA cohorts

OBJECTIVES

Evaluate gender differences with regard to baseline characteristics and outcome of therapy in cohorts of the SCOLTA (surveillance cohort long-term toxicity of antiretrovirals) project.

METHODS

The SCOLTA project is an active pharmacovigilance system for new antiretroviral drugs. Since 2002, patients were enrolled in nine cohorts (lopinavir, tenofovir, atazanavir, fosamprenavir, enfuvirtide, tipranavir, darunavir, raltegravir and maraviroc).

RESULTS

Two thousand one hundred and fifty-four patients were included in 5 PI cohorts; 607 (28.2%) were female. Women were younger and less frequently HCV-coinfected than men. At study entry, they were less frequently in CDC stage C, but CD4+ cells/mm(3) and detectable HIV-RNA were not different by gender. Women had triglycerides alterations less frequently than men, but showed a higher proportion of low HDL-cholesterol. Women were protected from incident grade 2-4 triglycerides increase (odds ratio=0.39, 95% confidence interval 0.18-0.88; P=0.02). Mean CD4+ cell count increased in both men and women; despite a non-significantly lower initial CD4+ level, women had a better immunological recovery. Women discontinued PI treatment for adverse events and their own will more frequently.

CONCLUSIONS

In these cohorts, gender distribution mirrored the Italian HIV population. Women were younger than men when they started their first ARV therapy and when they entered our cohorts. On the same treatment, they had a better immune response, though no significant difference emerged on virologic control and treatment durability. As compared to men, women appeared at lower risk of hypertriglyceridaemia. They stopped PI-based treatment of their own will more frequently than men, suggesting the need for a focused effort on adherence.

A meta-analysis of the efficacy and safety of unboosted atazanavir compared with ritonavir-boosted protease inhibitor maintenance therapy in HIV-infected adults with established virological suppression after induction

OBJECTIVES

Treatment simplification involving induction with a ritonavir (RTV)-boosted protease inhibitor (PI) replaced by a nonboosted PI (i.e. atazanavir) has been shown to be a viable option for long-term antiretroviral therapy. To evaluate the clinical evidence for this approach, we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating efficacy and safety in patients with established virological suppression.

METHODS

Several databases were searched without limits on time or language. Searches of conferences were also conducted. RCTs were included if they compared a PI/RTV regimen to unboosted atazanavir, after induction with PI/RTV. The meta-analysis was conducted using a random effects model for the proportion achieving virological suppression (i.e. HIV RNA < 50 and <400 HIV-1 RNA copies/mL), CD4 cell counts, lipid levels and liver function tests. Dichotomous outcomes were reported as risk ratios (RRs) and continuous outcomes as mean differences (MDs).

RESULTS

Five studies (n = 1249) met the inclusion criteria. The meta-analysis demonstrated no statistically significant difference in efficacy (i.e. HIV RNA < 50 copies/mL) between PI/RTV and unboosted atazanavir [RR = 1.04; 95% confidence interval (CI) 0.99 to 1.10], with no heterogeneity. Findings were similar in a subanalysis of studies where atazanavir/RTV was the only PI/RTV used during induction. Additional efficacy results support these findings. A significant reduction in total cholesterol (P < 0.00001), triglycerides (P = 0.0002), low-density lipoprotein (LDL) cholesterol (P = 0.009) and hyperbilirubinaemia (P = 0.02) was observed with unboosted atazanavir vs. PI/RTV.

CONCLUSIONS

The meta-analysis demonstrated that switching patients with virological suppression from an RTV-boosted PI to unboosted atazanavir leads to improvements in safety (i.e. blood parameter abnormalities) without sacrificing virological efficacy.

Revealing the metabolic sites of atazanavir in human by parallel administrations of D-atazanavir analogs

Atazanavir (Reyataz(®)) is an important member of the HIV protease inhibitor class. Because of the complexity of its chemical structure, metabolite identification and structural elucidation face serious challenges. So far, only seven non-conjugated metabolites in human plasma have been reported, and their structural elucidation is not complete, especially for the major metabolites produced by oxidations. To probe the exact sites of metabolism and to elucidate the relationship among in vivo metabolites of atazanavir, we designed and performed two sets of experiments. The first set of experiments was to determine atazanavir metabolites in human plasma by LC-MS, from which more than a dozen metabolites were discovered, including seven new ones that have not been reported. The second set involved deuterium labeling on potential metabolic sites to generate D-atazanavir analogs. D-atazanavir analogs were dosed to human in parallel with atazanavir. Metabolites of D-atazanavir were identified by the same LC-MS method, and the results were compared with those of atazanavir. A metabolite structure can be readily elucidated by comparing the results of the analogs and the pathway by which the metabolite is formed can be proposed with confidence. Experimental results demonstrated that oxidation is the most common metabolic pathway of atazanavir, resulting in the formation of six metabolites of monooxidation (M1, M2, M7, M8, M13, and M14) and four of dioxidation (M15, M16, M17, and M18). The second metabolic pathway is hydrolysis, and the third is N-dealkylation. Metabolites produced by hydrolysis include M3, M4, and M19. Metabolites formed by N-dealkylation are M5, M6a, and M6b.

Identification and structural elucidation of in vitro metabolites of atazanavir by HPLC and tandem mass spectrometry

Atazanavir (marketed as Reyataz®) is an important member of the human immunodeficiency virus protease inhibitor class. LC-UV-MS(n) experiments were designed to identify metabolites of atazanavir after incubations in human hepatocytes. Five major (M1-M5) and seven minor (M7-M12) metabolites were identified. The most abundant metabolite, M1, was formed by a mono-oxidation on the t-butyl group at the non-prime side. The second most abundant metabolite, M2, was also a mono-oxidation product, which has not yet been definitively identified. Metabolites, M3 and M4, were structural isomers, which were apparently formed by oxidative carbamate hydrolysis. The structure of M5 comprises the non-prime side of atazanavir which contains a pyridinyl-benzyl group. Metabolite M6a was formed by the cleavage of the pyridinyl-benzyl side chain, as evidenced by the formation of the corresponding metabolic product, the pyridinyl-benzoic acid (M6b). Mono-oxidation also occurred on the pyridinyl-benzyl group to produce the low abundance metabolite M8. Oxidation of the terminal methyl groups produced M9 and M10, respectively, which have low chemical stability. Trace-level metabolites of di-oxidations, M11 and M12, were also detected, but the complexity of the molecule precluded identification of the second oxidation site. To our knowledge, metabolites M6b and M8 have not been reported.

Pharmacokinetic-pharmacodynamic modeling of unboosted Atazanavir in a cohort of stable HIV-infected patients

Limited data on the pharmacokinetics and pharmacodynamics (PK/PD) of unboosted atazanavir (uATV) in treatment-experienced patients are available. The aim of this work was to study the PK/PD of unboosted atazanavir in a cohort of HIV-infected patients. Data were available for 58 HIV-infected patients (69 uATV-based regimens). Atazanavir concentrations were analyzed by using a population approach, and the relationship between atazanavir PK and clinical outcome was examined using logistic regression. The final PK model was a linear one-compartment model with a mixture absorption model to account for two subgroups of absorbers. The mean (interindividual variability) of population PK parameters were as follows: clearance, 13.4 liters/h (40.7%), volume of distribution, 71.1 liters (29.7%), and fraction of regular absorbers, 0.49. Seven subjects experienced virological failure after switch to uATV. All of them were identified as low absorbers in the PK modeling. The absorption rate constant (0.38 ± 0.20 versus 0.75 ± 0.28 h(-1); P = 0.002) and ATV exposure (area under the concentration-time curve from 0 to 24 h [AUC(0-24)], 10.3 ± 2.1 versus 22.4 ± 11.2 mg · h · liter(-1); P = 0.001) were significantly lower in patients with virological failure than in patients without failure. In the logistic regression analysis, both the absorption rate constant and ATV trough concentration significantly influenced the probability of virological failure. A significant relationship between ATV pharmacokinetics and virological response was observed in a cohort of HIV patients who were administered unboosted atazanavir. This study also suggests that twice-daily administration of uATV may optimize drug therapy.

Pharmacologic boosting of atazanavir in maintenance HIV-1 therapy: the COREYA propensity-score adjusted study

Background

Among HIV-1 infected patients who achieved virologic suppression, the use of atazanavir without pharmacologic boosting is debated. We evaluated the efficacy and tolerance of maintenance therapy with unboosted atazanavir in clinical practice.

Methods and Results

This multicenter retrospective cohort study evaluated the efficacy of switching HIV-1-infected patients controlled on triple therapy to unboosted (ATV₀, n = 98) versus ritonavir-boosted atazanavir (ATV/r, n = 254) +2 nucleos(t)ide reverse transcriptase inhibitors. The primary endpoint was time to virologic failure (VF, >200 copies/mL). ATV groups were compared controlling for potential confounding bias by inverse probability weighted Cox analysis and propensity-score matching. Overall and adjusted VF rates were similar for both strategies. Both strategies improved dyslipidemia and creatininemia, with less jaundice in the ATV₀ group.

Conclusion

In previously well-suppressed patients, within an observational cohort setting, ATV₀–based triple-therapy appeared as effective as ATV/r- based triple-therapy to maintain virologic suppression, even if co-administered with TDF, but was better tolerated.

Unboosted atazanavir for treatment of HIV infection: rationale and recommendations for use

Atazanavir (Reyataz®) is a protease inhibitor (PI) for the treatment of HIV infection. Several trials have demonstrated the good efficacy and toxicity profile of atazanavir boosted by ritonavir (atazanavir/r). However, several toxicity events and pharmacokinetic issues due to drug-to-drug interactions (partly related to ritonavir) may complicate atazanavir/r therapy. This is why regimens with unboosted atazanavir have been experimented with and are used in clinical practice. The aim of this article is to identify the clinical settings in which unboosted atazanavir may be a safe and effective option for the long-term control of HIV replication. Despite the fact that a favourable lipid profile and good gastrointestinal tolerability have been reported in comparative trials, unboosted atazanavir should not be considered an optimal choice for treatment-naive patients. In fact, boosting with ritonavir produces higher atazanavir plasma levels, which are beneficial in terms of efficacy, especially in untreated patients with high plasma HIV RNA. Clinical data indicate that, in patients with sustained undetectable HIV RNA and without previous virological failure or HIV drug resistance-associated mutations, a switch to unboosted atazanavir-based regimens is a feasible option to control and prevent toxicity events, especially in patients who cannot tolerate ritonavir and in those with severe hyperbilirubinaemia on atazanavir/r. Moreover, while unboosted atazanavir must not be used in pregnant women, it is a recommended option in special populations, such as patients with moderate liver insufficiency. Lastly, unboosted atazanavir in combination with raltegravir may allow the construction of a well tolerated and effective regimen without nucleoside reverse transcriptase inhibitors in patients for whom these drugs are contraindicated. In conclusion, there is a good rationale, significant clinical interest and accumulating clinical experience with unboosted atazanavir-based regimens, although this formulation should be used only in specific situations and as a maintenance strategy. Moreover, therapeutic drug monitoring could be useful in specific circumstances (such as in patients with liver impairment or in case of potential drug-drug interactions).

Switching to unboosted atazanavir reduces bilirubin and triglycerides without compromising treatment efficacy in UGT1A1*28 polymorphism carriers

OBJECTIVES

Hyperbilirubinaemia is a frequent complication of atazanavir-containing antiretroviral therapy and its severity is related to UDP-glucuronosyl transferase (UGT) 1A1*28 polymorphism. The aim of this study was to evaluate the safety and outcome of unboosted atazanavir-containing regimens based on the genetic constitution.

METHODS

Fifty-one HIV-1-infected patients on boosted atazanavir were prospectively enrolled in the study. Twenty-five patients with a UGT1A1*28 allele switched to 400 mg of unboosted atazanavir.

RESULTS

At baseline, UGT1A1 heterozygous and homozygous patients had significantly higher bilirubin levels than wild-type (P = 0.012 and P < 0.001, respectively). After ritonavir removal, a reduction was observed in total bilirubin (from 4.09 to 1.82 mg/dL; P < 0.001), γ-glutamyl transpeptidase (P = 0.015), triglycerides (P = 0.03) and total cholesterol (P = 0.05). No significant changes in CD4 T cell count and no increases in viral load were observed 12 months after unboosting. Plasma drug monitoring after ritonavir removal revealed the presence of therapeutic atazanavir concentrations in all patients except one with poor therapy adherence.

CONCLUSIONS

UGT1A1*28 is significantly related to hyperbilirubinaemia in HIV-1 patients receiving atazanavir. Genotyping before the initiation of antiretroviral therapy can reduce the emergence of severe hyperbilirubinaemia. Unboosted atazanavir-containing therapy is safe and efficacious in patients with an undetectable viral load with a UGT1A1*28 polymorphism, allowing the use of atazanavir in patients otherwise likely unable to receive it.

Population pharmacokinetics of atazanavir/ritonavir in HIV-1-infected children and adolescents

AIMS

To investigate atazanavir (ATV) population pharmacokinetics in children and adolescents, establish factors that influence ATV pharmacokinetics and investigate the ATV exposure after recommended doses.

METHODS

Atazanavir concentrations were measured in 51 children/adolescents during a mean therapeutic monitoring follow up of 6.6 months. A total of 151 ATV plasma concentrations were obtained, and a population pharmacokinetic model was developed with NONMEM. Patients received ATV alone or boosted with ritonavir.

RESULTS

Atazanavir pharmacokinetics was best described by a one-compartment model with first-order absorption and elimination. The effect of bodyweight was added on both apparent elimination clearance (CL/F) and volume of distribution using allometric scaling. Atazanavir CL/F was reduced by ritonavir by 45%. Tenofovir disoproxil fumarate (TDF) co-medication (300 mg) increased significantly by 25% the atazanavir/ritonavir (ATV/r) CL/F. Mean ATV/r CL/F values with or without TDF were 8.9 and 7.1 L h(-1) (70 kg)(-1), respectively. With the recommended 250/100 mg and 300/100 mg ATV/r doses, the exposure was higher than the mean adult steady-state exposure in the bodyweight range of 32-50 kg.

CONCLUSIONS

To target the mean adult exposure, children should receive the following once-daily ATV/r dose: 200/100 mg from 25 to 39 kg, 250/100 mg from 39 to 50 kg and 300/100 mg above 50 kg. When 300 mg TDF is co-administered, children should receive (ATV/r) at 250/100 mg between 35 and 39 kg, then 300/100 mg over 39 kg.

HIV protease inhibitors: present and future

Antiretroviral therapy offers many options, largely based on the next-generation protease inhibitors (PIs). Early PI-based treatments involve high pill burdens and dosing schedules, and concerns of long-term toxicities are well established. In patients who have already achieved viral suppression, novel agents and strategies should be used to simplify the dosing treatment, reduce adverse events or preserve drug options. In experienced patients, drug escalation between PIs and different associations between classes allow virological suppression to be reached in the majority of patients. Therefore, there is a persistent clinical need for the discovery and development of new protease inhibitors. Several firms are trying to develop new types of PIs that will not be cross-resistant with existing drugs and will not require ritonavir boosting. This article aims to offer an overview on present drug options recommended for treatment in naive and experienced patients, new strategies currently undergoing clinical evaluation and new compounds in the pipeline.