Comparison of atazanavir with lopinavir/ritonavir in patients with prior protease inhibitor failure: a randomized multinational trial

Comparative Assessment of the Magnitude of Hyperlipidemia in HIV-Infected Patients Receiving Lopinavir/r- and Atazanavir/r-Based Antiretroviral Drugs

Objective:

To assess prevalence of hyperlipidemia in patients receiving lopinavir boosted with ritonavir (LPV/r) and atazanavir boosted with ritonavir (ATV/r) antiretroviral drugs.

Methods:

HIV-infected patients (300) were recruited in the study between December 2015 and April 2016. Lipid profile including triglycerides (TG), high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol (LDL-C) were assessed.

Results:

Prevalence of derangement in TG was 71.0% in patients using LPV/r compared to 44% in those using ATV/r (P = .01). Use of LPV/r was independently associated with increased total cholesterol (TC; P = .001) and TG (P = .0003). Females had raised levels of TC compared to males (P = .00008). Body mass index of ≥ 25 kg/m² was also associated with raised TC (P = .002) and LDL-C (P = .006).

Conclusion:

LPV/r was significantly associated with lipid derangements, indicating the need to regularly monitor lipid profile in patients using LPV/r.

Atazanavir / ritonavir versus Lopinavir / ritonavir-based combined antiretroviral therapy (cART) for HIV-1 infection: a systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis was conducted to evaluate the safety and effectiveness of Atazanavir/ritonavir over lopinavir/ritonavir in human immunodeficiency virus-1 (HIV-1) infection.

METHODS

Clinical trials with a head-to-head comparison of atazanavir/ritonavir and lopinavir/ritonavir in HIV-1 were included. Electronic databases: PubMed/Medline CENTRAL, Embase, Scopus, and Web of Science were searched. Viral suppression below 50 copies/ml at the longest follow-up period was the primary outcome measure. Grade 2-4 treatment-related adverse drug events, lipid profile changes and grade 3-4 bilirubin elevations were used as secondary outcome measures.

RESULTS

A total of nine articles from seven trials with 1938 HIV-1 patients were included in the current study. Atazanavir/ritonavir has 13% lower overall risk of failure to suppress the virus level < 50 copies/ml than lopinavir/ritonavir in fixed effect model (pooled RR: 0.87; CI: 0.78, 0.96; P=0.006). The overall risk of hyperbilirubinemia is very high for atazanavir/ritonavir than lopinavir/ritonavir in the random effects model (pooled RR: 45.03; CI: 16.03, 126.47; P< 0.0001).

CONCLUSION

Atazanavir/ritonavir has a better viral suppression at lower risk of lipid abnormality than lopinavir/ritonavir. The risk and development of hyperbilirubinemia from atazanavir-based regimens should be taken into consideration both at the time of prescribing and patient follow-up.

Six-Year Immunologic Recovery and Virological Suppression of HIV Patients on LPV/r-Based Second-Line Antiretroviral Treatment: A Multi-Center Real-World Cohort Study in China

The World Health Organization guidelines recommend lopinavir/ritonavir (LPV/r) as a second-line antiretroviral therapy (ART) for HIV-infected adults in middle-income and low-income countries as a protease inhibitor boost based on clinical trials; however, the real-world safety and efficacy remain unknown. Therefore, we conducted a large-scale, multicenter retrospective cohort study to evaluate the efficacy and safety of LPV/r-based ART among HIV-infected adults in China in whom first-line therapy failed. The data were obtained from a national database covering 17 clinics in China for six years of follow-up from 2009 to 2016. Failure of first-line treatment was determined according to a viral load at least 400 copies/ml at week 48, non-completers at week 48 for any reason, and those who switched ART before week 48 for any reason such as side effects. Treatment effectiveness was assessed by the rate of CD4⁺T cell recovery, defined as >500 cells/mm³, and the proportion of patients achieving viral suppression, defined as <400 or <50 copies/ml according to the methods used during treatment. Safety was assessed by rates of LPV/r-related adverse events (AEs), including lipid disorder, severe abnormal liver function, myelosuppression, and renal function. Between 2009 and 2016, 1196 participants (median, 36 years old; IQR, 30–43 years) were ultimately enrolled. All patients had been on LPV/r-based second-line ART treatment for more than one year after failure of any first-line ART regimen. Overall CD4⁺T cell counts increased from 138 cells/mm³ to 475 cells/mm³ and 37.2% of all participants reached CD4 recovery. Viral suppression rates dramatically increased at the end of the first year (<400 copies/ml, 88.8%; <50 copies/ml, 76.7%) and gradually increased during follow-up (<400 copies/ml, 95.8%; <50 copies/ml, 94.4%). The most frequently reported AEs were LPV/r-induced lipid disorders with no obvious increase on LDL-C at follow-up visits. This is the first real-world LPV/r-based second-line treatment study to cover such a large population in China. These results provide strong clinical evidence that LPV/r-based second-line ART is effective in increasing CD4⁺T cell counts and viral suppression rates with tolerable side effects in HIV-infected adults in China in whom first-line treatment had failed.

Assessing the Efficacy of Lopinavir/Ritonavir-Based Preferred and Alternative Second-Line Regimens in HIV-Infected Patients: A Meta-Analysis of Key Evidence to Support WHO Recommendations

Background: Nucleoside reverse transcriptase inhibitors (NRTIs) and non-NRTIs (NNRTIs) with boosted protease inhibitors are included in standardized first-line and second-line regimens. Recent World Health Organization (WHO) guidelines recommend a boosted protease inhibitor (PI) combined with 2 NRTIs or raltegravir as a second-line regimen.

Objective: Ritonavir-boosted lopinavir (LPV/r) is known as a key second-line antiretroviral therapy (ART) in resource-limited settings. We carried out a meta-analysis to analyze virologic suppression and effectiveness of LPV/r-based second-line therapy in HIV-infected patients.

Methods: In this meta-analysis, we searched randomized controlled trials and observational cohort studies to evaluate outcomes of second-line ART for patients with HIV who failed first-line therapy. A systematic search was conducted in Pubmed, Cochrane Library, and Embase from inception to January 2018. Outcomes included viral suppression, CD4 cell counts, drug resistance, adverse events, and self-reported adherence. We assessed comparative efficacy and safety in a meta-analysis. Data analysis was performed using RevMan 5.3 and Stata12.0.

Results: Nine studies comprising 3,923 patients were included in the meta-analysis. The overall successful virologic suppression rate of the second-line regimen was 77% (ITT) and 87% (PP) at 48 weeks with a plasma HIV RNA load of <400 copies/mL. No statistical significance was found in CD4 cell count recoveries between LPV/r plus 2-3 NRTIs and simplified regimens (LPV/r plus raltegravir) at 48 weeks (P = 0.09), 96 weeks (P = 0.05), and 144 weeks (P = 0.73). Four studies indicated that the virus had low-level resistance to LPV/r, and the most common clinically significant PI-resistance mutations were 46I, 54V, 82A/82F, and 76V; however, no virologic failure due to LPV/r resistance was detected. In addition, no statistical significance was found between the two groups in self-reported adherence [relative risks (RR) = 1.03,95% confidence interval (CI) 1.00, 1.07, P = 0.06], grade 3 or 4 adverse events (RR = 0.84, 95% CI 0.64, 1.10, P = 0.20) or serious events (RR = 0.85, 95% CI 0.77, 1.17, P = 0.62).

Conclusions: These results suggest that the LPV/r-based regimen demonstrates efficacious and low resistance as second-line antiretroviral therapy.Both LPV/r plus 2-3 NRTIs and LPV/r plus RAL regimens improved CD4 cell counts. There was no evidence of superiority of simplified regimens over LPV/r plus 2-3 NRTIs.

Second line antiretroviral therapy for treatment of HIV in Asia

Limited access to virological monitoring has led to a high prevalence of resistance to nucleoside reverse transcriptase inhibitors (NRTIs) at the time of first line failure in most studies from low- and middle-income countries (LMIC). Nevertheless, the current standard of care is to include NRTIs in second line regimens. The activity of tenofovir/emtricitabine following failure of stavudine/lamivudine or zidovudine/lamivudine is dependent on the sensitivity of the monitoring strategy used during first line therapy and the threshold for switching, whereas these factors are less important if the opposite sequencing strategy is used. Boosted protease inhibitors (PIs) are the foundation of effective second-line therapy with demonstrated efficacy in early salvage regimens and high barrier to resistance. Lopinavir/ritonavir and ritonavir-boosted atazanavir have recently been described by the World Health Organization as preferred boosted PIs for use in LMIC. Alternative approaches currently under investigation include boosted PI monotherapy, dual boosted PIs, and the combination of raltegravir (an HIV integrase inhibitor) and a boosted PI.

Comparative efficacy and safety of second-line antiretroviral therapy for treatment of HIV/AIDS: a systematic review and network meta-analysis

BACKGROUND

Selection of optimal second-line antiretroviral therapy (ART) has important clinical and programmatic implications. To inform the 2016 revision of the WHO ART guidelines, we assessed the comparative effectiveness and safety of available second-line ART regimens for adults and adolescents in whom first-line non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimens have failed.

METHODS

In this systematic review and network meta-analysis, we searched for randomised controlled trials and prospective and retrospective cohort studies that evaluated outcomes in treatment-experienced adults living with HIV who switched ART regimen after failure of a WHO-recommended first-line NNRTI-based regimen. We searched Embase, MEDLINE, and the Cochrane Central Register of Controlled Trials for reports published from Jan 1, 1996, to Aug 8, 2016, and searched conference abstracts published from Jan 1, 2014, to Aug 8, 2016. Outcomes of interest were viral suppression, mortality, AIDS-defining illnesses or WHO stage 3-4 disease, discontinuations, discontinuations due to adverse events, and serious adverse events. We assessed comparative efficacy and safety in a network meta-analysis, using Bayesian hierarchical models.

FINDINGS

We identified 12 papers pertaining to eight studies, including 4778 participants. The network was centred on ritonavir-boosted lopinavir plus two nucleoside or nucleotide reverse transcriptase inhibitors. Ritonavir-boosted lopinavir monotherapy was the only regimen inferior to others. With the lower estimate of the 95% credible interval (CrI) not exceeding the predefined threshold of 15%, evidence at 48 weeks supported the non-inferiority of ritonavir-boosted lopinavir plus raltegravir to regimens including ritonavir-boosted protease inhibitor plus two NRTIs with respect to viral suppression (odds ratio 1·09, 95% CrI 0·88-1·35). Estimated efficacy of ritonavir-boosted darunavir (800 mg once daily) was too imprecise to determine non-inferiority. Overall, regimens did not differ significantly with respect to continuations, AIDS-defining illnesses or WHO stage 3-4 disease, or mortality.

INTERPRETATION

With the exception of ritonavir-boosted lopinavir plus raltegravir, the evidence base is unable to provide strong support to alternative second-line options to ritonavir-boosted protease inhibitor plus two NRTIs, and thus more trials are warranted.

FUNDING

WHO.

Pharmacokinetics of Unboosted Atazanavir in Treatment-experienced HIV-infected Children, Adolescents and Young Adults

HIV protease inhibitor use in pediatrics is challenging due to the poor palatability and/or toxicity of concomitant low-dose ritonavir. Atazanavir without ritonavir (unboosted) is not recommended for patients with prior virologic failure, a common problem for perinatally-infected adolescents. Atazanavir 400 mg once-daily provided suboptimal exposure. Higher unboosted doses or splitting the daily dose to twice-daily warrants investigation in this treatment-experienced population.

A simple, efficient, and sensitive method for simultaneous detection of anti-HIV drugs atazanavir, ritonavir, and tenofovir by use of liquid chromatography-tandem mass spectrometry

In the treatment of HIV infection, a combination of anti-HIV drugs is commonly used in highly active antiretroviral therapy (HAART). One such combination recommended for clinical therapy consists of the two HIV protease inhibitors atazanavir and ritonavir and the HIV nucleotide reverse transcriptase inhibitor tenofovir. The detection of plasma and cell drug concentrations provides an assessment of actual drug exposure and patient compliance. We thus developed a simple, efficient, and sensitive method to simultaneously extract and detect these three drugs in plasma and peripheral blood mononuclear cells. The use of a liquid-liquid extraction followed by protein precipitation provided a simple process, yielding a high recovery rate for all three drugs in plasma (>92%) and in cells (>86%). The liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay was able to detect 0.01, 0.25, and 2.5 pg (2, 50, and 500 pg/ml, respectively) in 5 μl for atazanavir, ritonavir, and tenofovir, respectively. Validation of the method exhibited high precision and accuracy. This method was subsequently applied to a primate study to determine the concentrations of all three drugs in both plasma and cell samples. This validated method can be useful for an evaluation of drug concentrations in biological samples in an efficient and sensitive manner.

Efficacy and biological safety of lopinavir/ritonavir based anti-retroviral therapy in HIV-1-infected patients: a meta-analysis of randomized controlled trials

Lopinavir/ritonavir (LPV/r) is the first ritonavir-boosted protease-inhibitor used in second-line anti-retroviral treatment (ART) in resource-limited regions. To evaluate the efficacy and safety outcomes of LPV/r in treatment-naïve and -experienced HIV-infected adults and pregnant women, we performed a meta-analysis of randomized controlled trials. Ten cohorts from 8 articles involving 2,584 ART-naïve patients, 5 cohorts from 4 articles involving 1,124 ART-experienced patients, and 8 cohorts from 7 articles involving 2,191 pregnant women were selected for the meta-analyses. For ART-naïve patients, the virologic response rate (72.3%) of LPV/r combined with tenofovir (TDF) plus lamivudine/emtricitabine (3TC/FTC) arms was significantly greater than that of LPV/r plus non-TDF-FTC arms (65.5%, p = 0.047). For ART-experienced patients, the use of LPV/r revealed a 55.7% probability of virologic success. The incidence of abnormal total cholesterol (6.9%) for ART-experienced patients was significantly lower than that for ART-naïve patients (13.1%, p < 0.001). The use of LPV/r in pregnant women revealed a mother-to-child transmission (MTCT) rate of 1.1%, preterm birth rate of 13.2%, and low birth weight rate of 16.2%. Our meta-analysis indicated that LPV/r was an efficacious regimen for ART-naïve patients and was more tolerable for ART-experienced patients. LPV/r also displayed a significant effect in preventing MTCT.

Long-term safety and efficacy of atazanavir-based therapy in HIV-infected infants, children and adolescents: the Pediatric AIDS Clinical Trials Group Protocol 1020A

BACKGROUND

Atazanavir (ATV) is an attractive option for the treatment of Pediatric HIV infection, based on once-daily dosing and the availability of a formulation appropriate for younger children. Pediatric AIDS Clinical Trials Group 1020A was a phase I/II open label study of ATV (with/without ritonavir [RTV] boosting)-based treatment of HIV-infected children; here we report the long-term safety and virologic and immunologic responses.

METHODS

Antiretroviral-naïve and experienced children, ages 91 days to 21 years, with baseline plasma HIV RNA > 5000 copies/mL (cpm) were enrolled at sites in the United States and South Africa.

RESULTS

Of 195 children enrolled, 142 (73%) subjects received ATV-based regimens at the final protocol recommended dose; 58% were treatment naive. Overall, at week 24, 84/139 subjects (60.4%) and at week 48, 83/142 (58.5%) had HIV RNA ≤ 400 cpm. At week 48, 69.5% of naïve and 43.3% of experienced subjects had HIV RNA ≤ 400 cpm; median CD4 increase was 196.5 cells/mm. The primary adverse event (AE) was increased serum bilirubin; 9% of subjects had levels ≥ 5.1 times upper limit of normal (ULN) and 1.4% noted jaundice. Three percent of subjects experienced grade 2 or 3 prolongation in PR or QTc intervals. At week 48, there was a 15% increase in total cholesterol (TC), with TC > 199 mg/dL increasing from 1% at baseline to 5.7%.

CONCLUSIONS

Use of once-daily ATV, with/without RTV, was safe and well tolerated in children, with acceptable levels of viral suppression and CD4 count increase. The primary AE, as expected, was an increase in bilirubin levels.

Pharmacokinetics of Etravirine Combined with Atazanavir/Ritonavir and a Nucleoside Reverse Transcriptase Inhibitor in Antiretroviral Treatment-Experienced, HIV-1-Infected Patients

Objectives. TEACH (NCT00896051) was a randomized, open-label, two-arm Phase II trial to investigate the pharmacokinetic interaction between etravirine and atazanavir/ritonavir and safety and efficacy in treatment-experienced, HIV-1-infected patients. Methods. After a two-week lead-in of two nucleoside reverse transcriptase inhibitors (NRTIs) and atazanavir/ritonavir 300/100 mg, 44 patients received etravirine 200 mg bid with one NRTI, plus atazanavir/ritonavir 300/100 mg or 400/100 mg qd (n = 22 each group) over 48 weeks. Results. At steady-state etravirine with atazanavir/ritonavir 300/100 mg qd or 400/100 mg qd decreased atazanavir C min⁡ by 18% and 9%, respectively, with no change in AUC24 h or C max⁡ versus atazanavir/ritonavir 300/100 mg qd alone (Day -1). Etravirine AUC12 h was 24% higher and 16% lower with atazanavir/ritonavir 300/100 or 400/100 mg qd, respectively, versus historical controls. At Week 48, no significant differences were seen between the atazanavir/ritonavir groups in discontinuations due to adverse events (9.1% each group) and other safety parameters, the proportion of patients with viral load <50 copies/mL (intent-to-treat population, noncompleter = failure) (50.0%, atazanavir/ritonavir 300/100 mg qd versus 45.5%, 400/100 mg qd), and virologic failures (31.8% versus 27.3%, resp.). Conclusions. Etravirine 200 mg bid can be combined with atazanavir/ritonavir 300/100 mg qd and an NRTI in HIV-1-infected, treatment-experienced patients without dose adjustment.

Cardiovascular disease associated with the human immunodeficiency virus: an update

OPINION STATEMENT

With the advent of increasingly available antiretroviral therapy (ART), the life expectancy of HIV-infected persons is increasing. As they age, HIV-infected persons have increased propensity to typical diseases of aging including cardiovascular disease and accelerated atherosclerosis. The pathogenesis of HIV-associated atherosclerosis is complex and involves a state of chronic inflammation, exposure to traditional risk factors, and metabolic side effects of ART. Treatment of HIV-associated atherosclerosis should include special attention to drug-drug interactions and is best accomplished by a multidisciplinary team experienced in the care of HIV-infected persons.

Switch strategies in antiretroviral therapy regimens

Despite great advances in antiretroviral therapy in the last decade, several limitations still remain such as adverse effects, lack of adherence and drug-drug interactions. Switching antiretroviral therapy in stable, virologically suppressed patients with the aim of improving tolerability and convenience is an expanding strategy in clinical practice. Several factors need to be taken into consideration when switching a suppressive regimen, such as previous virologic failure, genetic barrier of the new regimen, prior duration of virologic suppression and expected level of adherence. The most frequently used strategies include reductions in the number of pills, drugs or doses. Although switching strategies may be useful, not all the regimens used in clinical practice are based on data from randomized clinical trials and some may not be the best option for certain patients; therefore, therapy should be individualized taking into consideration available information as well as patient and drug characteristics.

Evaluation of atazanavir and darunavir interactions with lipids for developing pH-responsive anti-HIV drug combination nanoparticles

We evaluated two human immunodeficiency virus (HIV) protease inhibitors, atazanavir (ATV) and darunavir (DRV), for pH-dependent solubility, lipid binding, and drug release from lipid nanoparticles (LNPs). Both ATV and DRV incorporated into LNPs composed of pegylated and non-pegylated phospholipids with nearly 100% efficiency, but only ATV-LNPs formed stable lipid-drug particles and exhibited pH-dependent drug release. DRV-LNPs were unstable and formed mixed micelles at low drug-lipid concentrations, and thus are not suitable for lipid-drug particle development. When ATV-LNPs were prepared with ritonavir (RTV), a metabolic and cellular membrane exporter inhibitor, and tenofovir (TFV), an HIV reverse-transcriptase inhibitor, stable, scalable, and reproducible anti-HIV drug combination LNPs were produced. Drug incorporation efficiencies of 85.5 ± 8.2, 85.1 ± 7.1, and 6.1 ± 0.8% for ATV, RTV, and TFV, respectively, were achieved. Preliminary primate pharmacokinetic studies with these pH-responsive anti-HIV drug combination LNPs administered subcutaneously produced detectable plasma concentrations that lasted for 7 days for all three drugs. These anti-HIV LNPs could be developed as a long-acting targeted antiretroviral therapy.

Metabolic and body composition effects of newer antiretrovirals in HIV-infected patients

In the absence of a cure, HIV-infected patients are being successfully treated with antiretroviral therapies (ART) and living longer. Indeed, an increasing number of HIV-infected patients are living beyond the age of 50 years, and in that regard, the use of ART has transformed HIV into a chronic medical condition. As more HIV-infected patients are virologically controlled and living longer, the trajectory of disease morbidity has shifted, however, primarily from opportunistic infections and immune dysfunction to metabolic complications. Evidence suggests that HIV-infected patients acquire significant metabolic risks, including lipodystrophic changes, subclinical atherosclerosis, and insulin resistance. The etiology of these metabolic complications specifically in HIV-infected patients is not entirely clear but may be related to a complex interaction between long-term consequences of infection and HIV itself, chronic use of antiretrovirals, and underlying inflammatory processes. Previous classes of ART, such as protease inhibitors (PIs) and reverse transcriptase inhibitors, have been implicated in altering fat redistribution and lipid and glucose homeostasis. Advances in drug development have introduced newer ART with strategies to target novel mechanisms of action and improve patient adherence with multi-class drug combinations. In this review, we will focus on these newer classes of ART, including selected entry inhibitors, integrase inhibitors, and multi-class drug combinations, and two newer PIs, and the potential of these newer agents to cause metabolic complications in HIV-infected patients. Taken together, further reduction of morbidity in HIV-infected patients will require increasing awareness of the deleterious metabolic complications of ART with subsequent management to mitigate these risks.

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.

Differences in implementation of HIV/AIDS clinical research in developed versus developing world: an evidence-based review on protease inhibitor use among women and minorities

The aim of this revision is to evaluate ethnicity and gender rate of enrolment in registrative clinical trials of the protease inhibitors (Pis) from 1996 to 2009. Company-sponsored, phase II or III registrative clinical trials of PIs were evaluated. Forty-nine clinical trials were included. Clinical trials were conducted in centres in North America ( n = 39), Central-South America ( n = 22), Europe ( n = 22), Africa ( n = 8), Asia ( n = 5), Australia ( n = 10). Overall mean age was 39.6 years; median proportion of women was 16.3%. The most represented ethnic group was Caucasian. A test for trend over time (1996-2009) shows a significant increase in the proportion of women included ( P = 0.012), and a decrease in the proportion of Caucasians included, reaching borderline significance ( P = 0.061). An inverse correlation was observed between the proportion of Caucasians and that of women enrolled in each study ( r = 0.65, P < 0.0001). Women were less likely to be included in double-blind studies (11.2% versus 17%, P = 0.019). Clinical trials for treatment-naive subjects were more likely to enrol ethnicities other than Caucasian compared with Caucasian (44.7% versus 27.1 %, respectively, P = 0.04). Rates of enrolment of minorities in registrative clinical trials for PIs show a positive trend since 1996, mirroring the growing number of people of different ethnic groups accessing ART.

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).

Diarrhea associated with lopinavir/ritonavir-based therapy: results of a meta-analysis of 1469 HIV-1-infected participants

BACKGROUND

Antiretroviral therapy is associated with adverse events (AEs). The most frequently reported AE associated with lopinavir/ritonavir (LPV/r) containing regimens is diarrhea. The objective of this meta-analysis is to describe the incidence, prevalence, and duration of diarrhea in individuals taking LPV/r.

METHODS

This is a meta-analysis of Abbott-conducted clinical trials. Inclusion criteria included prospective randomized clinical trials with the LPV/r tablet formulation and had AE data (moderate/severe diarrhea) available through 48 weeks of treatment.

RESULTS

Three trials (total 1469 participants) met the inclusion criteria. In all, 11.2% of participants reported moderate/severe diarrhea by week 8, with median time to resolution of 7.4 weeks. The overall 48-week incidence of moderate/severe diarrhea was 15.5%. The discontinuation rate due to moderate/severe diarrhea was 1.3%.

CONCLUSIONS

Moderate/severe diarrhea occurred in less than 1 in 6 participants taking LPV/r, typically started in the first 8 weeks of treatment and infrequently resulted in premature discontinuation.

Lopinavir/ritonavir dosing during pregnancy in Brazil and maternal/infant laboratory abnormalities

OBJECTIVES

To describe laboratory abnormalities among HIV-infected women and their infants with standard and increased lopinavir/ritonavir (LPV/r) dosing during the third trimester of pregnancy.

METHODS

We evaluated data on pregnant women from NISDI cohorts (2002-2009) enrolled in Brazil, who received at least 28 days of LPV/r during the third pregnancy trimester and gave birth to singleton infants.

RESULTS

164 women received LPV/r standard dosing [(798/198 or 800/200 mg/day) (Group 1)] and 70 increased dosing [(> 800/200 mg/day) (Group 2)]. Group 1 was more likely to have advanced clinical disease and to use ARVs for treatment, and less likely to have CD4 counts > 500 cells/mm³. Mean plasma viral load was higher in Group 2. There were statistically significant, but not clinically meaningful, differences between groups in mean AST, ALT, cholesterol, and triglycerides. The proportion of women with Grade 3 or 4 adverse events was very low, with no statistically significant differences between groups in severe adverse events related to ALT, AST, total bilirubin, cholesterol, or triglycerides. There were statistically significant, but not clinically meaningful, differences between infant groups in ALT and creatinine. The proportion of infants with Grade 3 or 4 adverse events was very low, and there were no statistically significant differences in severe adverse events related to ALT, AST, BUN, or creatinine.

CONCLUSION

The proportions of women and infants with severe laboratory adverse events were very low. Increased LPV/r dosing during the third trimester of pregnancy appears to be safe for HIV-infected women and their infants.

Atazanavir/ritonavir-based combination antiretroviral therapy for treatment of HIV-1 infection in adults

In the past 15 years, improvements in the management of HIV infection have dramatically reduced morbidity and mortality. Similarly, rapid advances in antiretroviral medications have resulted in the possibility of life-long therapy with simple and tolerable regimens. Protease inhibitors have been important medications in regimens of combination antiretroviral therapy for the treatment of HIV. One of the recommended and commonly used therapies in this class is once-daily-administered atazanavir, pharmacologically boosted with ritonavir (atazanavir/r). Clinical studies and practice have shown these drugs, in combination with other antiretroviral agents, to be potent, safe and easy to use in a variety of settings. Atazanavir/r has minimal short-term toxicity, including benign bilirubin elevation, and has less potential for long-term complications of hyperlipidemia and insulin resistance compared with other protease inhibitors. A high genetic barrier to resistance and a favorable resistance profile make it an excellent option for initial HIV treatment or as the first drug utilized in the protease inhibitors class. Atazanavir/r is also currently being studied in novel treatment strategies, including combinations with new classes of antiretrovirals to assess nucleoside reverse transcriptase inhibitor-sparing regimens. In this article we review atazanavir/r as a treatment for HIV infection and discuss the latest information on its pharmacology, efficacy and toxicity.

Lopinavir/Ritonavir: a review of its use in the management of HIV-1 infection

Lopinavir/ritonavir (Kaletra®) is an orally administered coformulated ritonavir-boosted protease inhibitor (PI) comprising lopinavir and low-dose ritonavir. It is indicated, in combination with other antiretroviral agents, for the treatment of HIV-1 infection in adults, adolescents and children. Lopinavir/ritonavir is available as a tablet, soft-gel capsule and an oral solution for patients with difficulty swallowing. In well designed, randomized clinical trials, lopinavir/ritonavir, in combination with other antiretroviral therapies (ART), provided durable virological suppression and improved immunological outcomes in both ART-naive and -experienced adult patients with virological failure. Furthermore, lopinavir/ritonavir demonstrated a high barrier to the development of resistance in ART-naive patients. More limited data indicate that it is effective in reducing plasma HIV-1 RNA levels in paediatric patients. Lopinavir/ritonavir has served as a well established benchmark comparator for the noninferiority of other ritonavir-boosted PI regimens. Although generally well tolerated, lopinavir/ritonavir is associated with generally manageable adverse gastrointestinal side effects and hypertriglyceridaemia and hypercholesterolaemia, which may require coadministration of lipid-lowering agents to reduce the risk of coronary heart disease. Lopinavir/ritonavir, in combination with other ART agents, is a well established and cost-effective treatment for both ART-naive and -experienced patients with HIV-1 infection and, with successful management of adverse events, continues to have a role as an effective component of ART regimens for the control of HIV-1 infection.

Impact of atazanavir-based HAART regimen on the carotid intima-media thickness of HIV-infected persons: a comparative prospective cohort

OBJECTIVE

With the advent of highly active antiretroviral therapy regimens, it is crucial to consider their long-term benefits to risk ratios among HIV-infected persons. The impact of protease inhibitors on the cardiovascular risk is controversial.

DESIGN

This observational cohort was designed to investigate the cardiovascular impact of boosted atazanavir (ATV/r), a protease inhibitor that does not provide major dyslipidemia or insulin resistance.

SETTING

This study was carried out at the University Hospital of Brest (France).

PATIENTS

Among the 229 HIV-infected persons of the cohort, 33 cases treated by ATV/r-containing regimen since less than 6 months were compared to 99 age-matched and sex-matched ATV/r naive controls.

INTERVENTION

None.

MAIN OUTCOME MEASURE

The main outcome measure was carotid intima-media thickness (cIMT) at the baseline, 6, 12, and 18 months.

RESULTS

Although the cIMT was not different at inclusion (0.633 ± 0.05 vs. 0.666 ± 0.09, P = 0.07), the cIMT course significantly decreased (P = 0.018) in cases at 18 months. The differences remained significant even after adjustment on the variables that differed between cases and controls (P < 0.1) at inclusion (high-density lipoprotein cholesterol, cardiovascular family history) and the cumulated and current exposure to the nucleosidic reverse transcriptase inhibitor, nonnucleosidic reverse transcriptase inhibitor, and protease inhibitor class.

CONCLUSION

Despite similar HIV and cardiovascular characteristics at baseline, cIMT decreased after 6 months of follow-up among the patients exposed to ATV/r, even after adjustment for the exposure to the three antiretroviral classes. Considering the shortcomings of this study, especially the absence of randomization and the heterogeneity of the control group, the benefit of ATV/r treatment in patients with high cardiovascular should be confirmed by randomized trials.

Factors predictive of virological failure on atazanavir in 310 HIV-infected patients

We examined factors associated with virological failure in 310 HIV-infected patients receiving atazanavir (ATV). Independent links were identified with virological failure under ATV: virological failure previous history (P = 0.006) and ATV underdosing (P = 0.04). A maintenance therapy was protective (P = 0.01). The optimal therapeutic ranges of ATV concentration were found to be from 300 ng/ml (or 180 for patients treated with maintenance therapy) to 650 ng/ml for C24 and from 1000 ng/ml (or 500 for patients treated with maintenance therapy) to 2000 ng/ml for C12.

Lipid profiles in HIV-infected adults receiving atazanavir and atazanavir/ritonavir: systematic review and meta-analysis of randomized controlled trials

OBJECTIVES

To compare lipid profiles in HIV-infected adults receiving atazanavir-based regimens.

METHODS

We conducted a systematic review of randomized controlled trials (RCTs) comparing atazanavir or atazanavir/ritonavir with a comparator and evaluated lipids at 48 weeks. We searched MEDLINE, EMBASE, CENTRAL, LILACS, Current Controlled Trials, National Institutes of Health Clinical Trials Registry, trials at AIDSinfo and HIV conference proceedings to May 2009. Standardized mean difference (SMD) between study arms in change from baseline to week 48 in lipid parameters was determined weighted by study size and 95% confidence intervals (CI) were calculated.

RESULTS

Nine eligible RCTs were identified (n = 3346). SMDs (mmol/L) in four RCTs comparing atazanavir/ritonavir with a ritonavir-boosted protease inhibitor were: total cholesterol, -0.62 (95% CI -0.72, -0.51); low-density lipoprotein (LDL) cholesterol, -0.31 (95% CI -0.44, -0.17); high-density lipoprotein (HDL) cholesterol, -0.16 (95% CI -0.27, -0.06); non-HDL cholesterol, -0.58 (95% CI -0.69, -0.48); and triglycerides, -0.46 (95% CI -0.58, -0.34). Atazanavir compared with non-atazanavir (three RCTs) found lower total, LDL and non-HDL cholesterol, and triglycerides [SMD -0.87 mmol/L (95% CI -0.99, -0.76); -0.56 mmol/L (95% CI -0.67, -0.45); -0.88 mmol/L (95% CI -0.99, -0.76); and -0.56 mmol/L (95% CI -0.75, -0.36), respectively], but HDL cholesterol did not differ [-0.16 mmol/L (95% CI -0.49, 0.16)]. In the atazanavir/ritonavir versus atazanavir comparison (two RCTs), total [SMD 0.44 mmol/L (95% CI 0.23, 0.65)] and non-HDL cholesterol [SMD 0.44 mmol/L (95% CI 0.23, 0.65)] were higher, but HDL cholesterol, LDL cholesterol and triglycerides were not different.

CONCLUSIONS

At 48 weeks, plasma lipid concentrations were lower with atazanavir/ritonavir than with other ritonavir-boosted protease inhibitor regimens. Total and non-HDL cholesterol were higher with atazanavir/ritonavir than atazanavir alone.

Racial and sex disparities in life expectancy losses among HIV-infected persons in the united states: impact of risk behavior, late initiation, and early discontinuation of antiretroviral therapy

BACKGROUND

Most persons with human immunodeficiency virus (HIV) infection in the United States present to care with advanced disease, and many patients discontinue therapy prematurely. We sought to evaluate sex and racial/ethnic disparities in life-years lost as a result of risk behavior, late presentation, and early discontinuation of HIV care, and we compared these survival losses for HIV-infected persons with losses attributable to high-risk behavior and HIV disease itself.

METHODS

With use of a state-transition model of HIV disease, we simulated cohorts of HIV-infected persons and compared them with uninfected individuals who had similar demographic characteristics. We estimated non-HIV-related mortality with use of risk-adjusted standardized mortality ratios, as well as years of life lost because of late presentation and early discontinuation of antiretroviral therapy (ART) for HIV infection. Data from the national HIV Research Network, stratified by sex and race/ethnicity, were used for estimating CD4+ cell counts at ART initiation.

RESULTS

For HIV-uninfected persons in the United States who have risk profiles similar to those of individuals with HIV infection, the projected life expectancy, starting at 33 years of age, was 34.58 years, compared with 42.91 years for the general US population. Those with HIV infection lost an additional 11.92 years of life if they received HIV care concordant with guidelines; late treatment initiation resulted in 2.60 additional years of life lost, whereas premature ART discontinuation led to 0.70 more years of life lost. Losses from late initiation and early discontinuation were greatest for Hispanic individuals (3.90 years).

CONCLUSIONS

The high-risk profile of HIV-infected persons, HIV infection itself, as well as late initiation and early discontinuation of care, all lead to substantial decreases in life expectancy. Survival disparities resulting from late initiation and early discontinuation of therapy are most pronounced for Hispanic HIV-infected men and women. Interventions focused on risk behaviors, as well as on earlier linkage to and better retention in care, will lead to improved survival for HIV-infected persons in the United States.

Protease inhibitor therapy in resource-limited settings

PURPOSE OF REVIEW

The use of protease inhibitors in resource-limited settings will increase in coming years as HIV treatment cohorts mature. We review data available to guide the expanded use of protease inhibitors in these settings.

RECENT FINDINGS

The safety and effectiveness of protease inhibitors may be affected by the context of their use, yet limited data exist regarding the use of these agents in resource-limited settings in either first or subsequent regimens. Critically, data are needed regarding optimal regimens at time of first-line nonnucleoside reverse transcriptase inhibitor-based regimen failure. A number of alternative strategies are being investigated, including dual-boosting, monotherapy and dose reduction. Despite recent progress cost, storage requirements, drug interactions and formulation continue to hinder the use of protease inhibitors, particularly for children.

SUMMARY

Protease inhibitors are the core component of second-line therapy in resource-limited settings and are used in specific situations in first-line therapy. Use of second-line regimens has been more diverse than first line, but WHO has recently prioritized regimens containing lopinavir/ritonavir or ritonavir-boosted atazanavir. As use of protease inhibitors in resource-limited settings increases evidence needs to be accrued to guide further expanded use.

Atazanavir: a review of its use in the management of HIV-1 infection

Atazanavir (Reyataz), a protease inhibitor (PI), is approved in many countries for use as a component of antiretroviral therapy (ART) regimens for the treatment of adult, and in some countries in paediatric, patients with HIV-1 infection. ART regimens containing ritonavir-boosted atazanavir improved virological and immunological markers in adult patients with HIV-1 infection, and had similar efficacy to regimens containing lopinavir/ritonavir in treatment-naive and treatment-experienced patients. In addition, unboosted atazanavir was noninferior to ritonavir-boosted atazanavir in treatment-naive patients. Atazanavir is administered once daily and has a low capsule burden. Atazanavir, whether unboosted or boosted, was generally well tolerated and appeared to be associated with less marked metabolic effects, including less alteration of lipid levels, than other PIs. These properties mean that boosted atazanavir, and unboosted atazanavir in patients unable to tolerate ritonavir, continues to have a role as a component of ART regimens in patients with HIV-1 infection.

Unboosted atazanavir plus co-formulated lamivudine/abacavir as a ritonavir-sparing simplification strategy in routine clinical practice

OBJECTIVE

To assess the effectiveness and safety of antiretroviral therapy with unboosted atazanavir (400 mg once daily) plus co-formulated abacavir/lamivudine as a treatment simplification strategy in HIV-infected patients with sustained viral suppression in routine clinical practice.

METHODS

We performed a retrospective study including patients who were switched to unboosted atazanavir plus abacavir/lamivudine and whose HIV-1 RNA was <50 copies/mL. The primary endpoint was the percentage of subjects who maintained viral suppression after 48 weeks of follow-up. Secondary endpoints included the percentage of subjects who maintained viral suppression after 96 weeks of follow-up, the incidence of adverse events, changes in CD4+ T-cell count and in lipid profile, and the percentage of patients with subtherapeutic atazanavir trough concentrations during follow-up.

RESULTS

Forty-six patients were included. None had a prior history of resistance to protease inhibitors or to lamivudine or abacavir. The percentage of patients with viral suppression at Week 48 was 73.9% when all the included patients were considered (full dataset analysis) and 85.0% when only subjects on treatment were considered. There was a continuous immune recovery and an improvement in lipid profile during follow-up. Two thirds of the patients had subtherapeutic atazanavir trough concentrations in plasma in at least one determination during follow-up.

CONCLUSION

Antiretroviral therapy with unboosted atazanavir plus abacavir/lamivudine is safe and effective in the long term as a treatment simplification strategy in HIV-infected patients with sustained virological suppression in routine clinical practice.

HIV protease inhibitors: recent clinical trials and recommendations on use

BACKGROUND

HIV protease inhibitors (PIs) are potent antiretroviral drugs that represent a pivotal component of highly active antiretroviral therapy (HAART). PIs have evolved over the years to gain in potency, convenience, tolerability and genetic barrier to resistance.

OBJECTIVE

Updated summary of evidence-based information about the efficacy and safety of PIs on initial, simplification and rescue interventions in HIV patients.

METHODS

Review of available data reported in peer-reviewed journals, medical conferences and treatment guidelines.

RESULTS

Due to their characteristics, PIs are, and will remain, a cornerstone component in most lines of antiretroviral therapy. The antiviral activity, tolerability and convenience of PIs have improved significantly in recent years. Differences between compounds within this class may favour their use in specific situations, such as the friendly metabolic profile of atazanavir in patients with cardiovascular disease or the high genetic barrier of darunavir or tipranavir in heavily pretreated individuals with HIV.

Improving outcomes in state AIDS drug assistance programs

BACKGROUND

State AIDS Drug Assistance Programs (ADAPs) provide antiretroviral medications to patients with no access to medications. Resource constraints limit the ability of many ADAPs to meet demand for services.

OBJECTIVE

To determine ADAP eligibility criteria that minimize morbidity and mortality and contain costs.

METHODS

We used Discrete Event Simulation to model the progression of HIV-infected patients and track the utilization of an ADAP. Outcomes included 5-year mortality and incidence of first opportunistic infection or death and time to starting antiretroviral therapy (ART). We compared expected outcomes for 2 policies: (1) first-come first-served (FCFS) eligibility for all with CD4 count <or=350/microL (current standard) and (2) CD4 count prioritized eligibility for those with CD4 counts below a defined threshold.

RESULTS

In the base case, prioritizing patients with CD4 counts <or=250/microL led to lower 5-year mortality than FCFS eligibility (2.77 vs. 3.27 deaths per 1,000 person-months) and to a lower incidence of first opportunistic infection or death (5.55 vs. 6.98 events per 1,000 person-months). CD4-based eligibility reduced the time to starting ART for patients with CD4 counts <or=200/microL. In sensitivity analyses, CD4-based eligibility consistently led to lower morbidity and mortality than FCFS eligibility.

CONCLUSION

When resources are limited, programs that provide ART can improve outcomes by prioritizing patients with low CD4 counts.

Atazanavir: its role in HIV treatment

Azatanavir is a protease inhibitor (PI) approved for the treatment of HIV-1 infection. Atazanavir is a substrate and inhibitor of cytochrome P450 isozyme 3A and an inhibitor and inducer of P-glycoprotein. It has similar virologic efficacy as efavirenz and ritonavir-boosted lopinavir in antiretroviral-naive individuals. Its impact on lipids is less than other PIs and it is suitable for those in whom hyperlipidemia is undesirable. Ritonavir boosting of atazanavir enhances the bioavailability of atazanavir but may result in some elevation of lipids and is recommended for treatment-experienced patients and those receiving efavirenz or tenofovir. Ritonavir-boosted atazanavir has similar antiviral activity as ritonavir-boosted lopinavir in both antiretroviral therapy-naive and -experienced patients. Atazanavir causes unconjugated bilirubinemia in over 40% of patients but results in less than 2% discontinuations. Atazanavir is licensed for once-daily use and atazanavir/ritonavir competes with lopinavir/ritonavir as the most commonly prescribed PI.

[Clinical utility of atazanavir]

Atazanavir (ATV) is a protease inhibitor (PI) in which its main qualities, compared to other PI are dosing convenience, good tolerability and excellent metabolic profile. These characteristics makes it more like a nonnucleoside than a PI, but with the increased genetic barrier common to PI. It is indicated in initial treatment, simplification treatment or a change due to toxicity and in first line rescue treatment. The administering of ATV boosted with ritonavir (300/100 mg/d) has been approved in Europe in all clinical situations. In naïve patients it has been combined with practically all the nucleoside analogue pairs and has shown to be as effective as lopinavir/ritonavir and even efavirenz. In the USA, this indication has been approved for almost 5 years and ATV has become the most prescribed PI, while the EMEA has approved it this year. ATV is an optimal drug to replace other antiretrovirals in simplification strategies or changes due to toxicity. In several studies it has been shown that, in patients with good virological control, it can LPV/r or another PI, the therapeutic efficacy being maintained, with excellent tolerance and an improved lipid profile, and decreasing the cardiovascular risk. This strategy is widely used in Spain. In this scenario some patients could benefit from non-boosted ATV treatment (400 mg/d). ATV is an effective and very attractive option in first line rescue treatments in which the virus shows little or no resistance to PI, as its simplicity and tolerability can improve problems with compliance, the main cause of therapeutic failure. In patients with moderate resistance to PI, ATV is as effective as LPV/r. The survival of patients with HIV infection is increasingly longer and factors such as tolerability, cardiovascular risk and the adaptability of the treatment to the lifestyle of the patient, become more important, therefore ATV must play an important role in the treatment of HIV-infection.

Lopinavir/ritonavir in the treatment of HIV-1 infection: a review

Lopinavir/ritonavir is the first and only coformulated HIV-1 protease inhibitor (PI). Large clinical trials have demonstrated lopinavir/ritonavir's clinical efficacy in both antiretroviral-naïve and -experienced patients. The immunologic and virologic benefits of treatment with this agent have been proven in HIV-infected adults, adolescents, and children. Smaller studies support the use of lopinavir/ritonavir monotherapy as a therapeutic option in certain patients. The drug is characterized by a high genetic barrier to resistance, and appears to be more forgiving of non-adherence than earlier, unboosted PIs. The most frequent side effects observed are diarrhea, nausea, and vomiting. These gastrointestinal adverse effects are generally mild to moderate. Metabolic derangements, including hyperlipidemia and glucose intolerance, have also been observed in lopinavir/ritonavir recipients. As the menu of available antiretroviral agents continues to expand, lopinavir/ritonavir remains a proven and effective drug for the treatment of HIV infection.

Significant improvements in self-reported gastrointestinal tolerability, quality of life, patient satisfaction, and adherence with lopinavir/ritonavir tablet formulation compared with soft gel capsules

BACKGROUND

The tablet formulation of ritonavir-boosted lopinavir (LPV/r; Kaletra) has many advantages over the soft gel capsule (SGC) formulation, including lower pill count, no refrigeration requirement, and no dietary restrictions. These advantages may help improve patient compliance and therefore increase adherence to treatment. However, there are limited data regarding patient preferences and only recently was the comparative efficacy and tolerability data of LPV/r SGC versus tablet formulation presented at an international conference. To address this deficit, we conducted a market research survey to assess potential tolerability benefits, patient satisfaction, changes in adherence, and formulation preference in patients switching from SGCs to the tablet formulation. Data from 332 patients who switched from LPV/r SGCs twice-daily (BID) to tablets BID and 41 patients who switched from LPV/r SGCs BID or once daily (QD) to tablets QD were analyzed.

RESULTS

Switching from SGCs to a tablet formulation of LPV/r was associated with increased patient satisfaction, tolerability and self-reported adherence to treatment; gastrointestinal side effects were reduced. In addition, respondents indicated that they preferred the tablet formulation to the SGC.

CONCLUSION

The LPV/r tablet formulation provides HIV-infected patients with multiple benefits over the SGC in terms of tolerability and convenience. Additional assessments to further define the tolerability profile of the LPV/r tablet, including studies using once-daily dosing, are warranted.

Interruption of antiretroviral therapy and risk of cardiovascular disease in persons with HIV-1 infection: exploratory analyses from the SMART trial

BACKGROUND

The SMART trial found a raised risk of cardiovascular disease (CVD) events in patients undergoing CD4+ T cell-count guided intermittent antiretroviral therapy (ART) compared with patients on continuous ART. Exploratory analyses were performed to better understand the reasons for this observation.

METHODS

A total of 5,472 patients with CD4+ T-cell counts >350 cells/mm3 were recruited and randomized to either continuous ART (the viral suppression arm; VS) or CD4+ T-cell count-guided use of ART (the drug conservation arm; DC).

RESULTS

Major CVD events developed in 79 patients. The hazard ratio (HR) for risk of CVD events for DC versus VS was 1.57 (95% confidence interval 1.00-2.46; P=0.05). There was no evidence that being off ART or a higher current HIV viral load were associated with increased CVD risk. Total cholesterol and low-density lipoprotein cholesterol were reduced as a result of ART interruption in DC patients but so was high-density lipoprotein (HDL) cholesterol, leading to a net unfavourable change in the total/HDL cholesterol ratio.

CONCLUSIONS

Reasons for the higher risk of CVD for DC compared with VS patients remain unclear. There was no clear evidence to suggest that ART interruption per se or a higher HIV viral load were associated with an increased CVD risk in the DC group. Lipid changes were less favourable among DC compared with VS patients, which could offer a partial explanation.

Viro-immunologic response to ritonavir-boosted or unboosted atazanavir in a large cohort of multiply treated patients: the CARe Study

Currently, comparative data able to define the potency of boosted versus unboosted atazanavir in highly pretreated HIV-infected patients are limited. Specifically, in clinical practice it is very important to establish whether atazanavir-boosting with ritonavir warrants potency and efficacy that overcome the profile of unboosted drug. For this reason, our goal was to evaluate viro-immunologic determinants of response to atazanavir, in unboosted ATV400 or boosted ATV300/r formulation, from baseline to week 48 in highly pretreated HIV-infected patients enrolled in a prospective observational Italian study. Data from 354 patients included in an atazanavir "Early Access Program" (AI424-900) with baseline viremia 500 copies per milliliter or more and with an available virologic follow-up were examined using as-treated analysis. Of these, 200 (56.5%) and 154 (43.5%), respectively, received regimens containing ATV300/r or ATV400. Virologic success (VS) was defined as reaching viremia of less than 500 copies per milliliter during follow-up. Estimated median time to VS was 8 weeks in the ATV300/r group and 13 weeks in the ATV400 group. Proportion of patients achieving VS was higher in the ATV300/r group than in ATV400 group at week 12 (66% versus 47%), as well as at week 48 (86% versus 64%). At multivariate Cox regression, receiving ATV300/r dosing was independently associated with increased probability of achieving VS [adjusted hazard ratio (AHR): 1.57; 95% confidence interval (CI): 1.19-2.06]. Conversely, CDC stage C, higher baseline viral load, and more experience with protease inhibitors (PIs) were associated with poorer virologic response. In an unselected population of highly pretreated HIV-infected individuals, receiving atazanavir as part of antiretroviral regimen results in effective virologic response and immunologic recovery. The antiviral efficacy of atazanavir is greater when boosted with low-dose ritonavir.