Comparison of first-line antiretroviral therapy with regimens including nevirapine, efavirenz, or both drugs, plus stavudine and lamivudine: a randomised open-label trial, the 2NN Study

Antiretroviral therapy in advanced HIV-1 infection

Current recommendations state that antiretroviral therapy (ART) should be commenced before the onset of severe HIV-associated immune deficiency and the development of AIDS-defining infections or malignancies. However, many patients only present and are diagnosed with HIV infection when they already have advanced disease. The optimal treatment for patients with advanced HIV disease remains to be defined. Key management questions include whether the virological and immunological responses to ART are comparable to those seen in patients with less advanced disease; whether the efficacy of different antiretroviral (ARV) regimens differs in patients with advanced disease; and whether there is an increased risk of drug toxicity and the immune reconstitution inflammatory syndrome.

Recomendaciones CEVIHP/SEIP/AEP/PNS respecto al tratamiento antirretroviral en niños y adolescentes infectados por el VIH

OBJECTIVE

To update antiretroviral recommendations in antiretroviral therapy (ART) in HIV-infected children and adolescents.

METHODS

Theses guidelines have been formulated by a panel of members of the Plan Nacional sobre el SIDA (PNS) and the Asociacion Espanola de Pediatria (AEP) by reviewing the current available evidence of efficacy, safety, and pharmacokinetics in pediatric studies. Three levels of evidence have been defined according to the source of data: Level A: randomized and controlled studies; Level B: Cohort and case-control studies; Level C: Descriptive studies and experts' opinion.

RESULTS

When to start ART should be made on an individual basis, discussed with the family, considering the risk of progression according to age, CD4 and viral load, the ART-related complications and adherence. The ART goal is to reach a maximum and durable viral suppression. This is not always possible, even with clinical and immunologic improvement. The difficulties of permanent adherence and side-effects are resulting in a more conservative trend to initiate ART, and to less toxic and simpler strategies. Currently, combinations of at least three drugs are of first choice both in acute and chronic infection. They must include 2 NA 1 1 NN or 2 NA 1 1 PI. ART is recommended in all symptomatic patients and, with few exceptions, in all infants in the first year of life. Older asymptomatic children should start ART according to CD4 count, especially CD4 percentage, that vary with age. Despite potent salvage therapies, it is common not to reach viral undetectability. Therapeutical options when ART fails are scarce due to cross-resistance. The cause of failure must be identified. Occasionally, there exists clinical and/or immunological progression, and a change of therapy with at least two new drugs still active for the patient, is warranted with the aim of increasing the CD4 count to a lower level of risk. Toxicity and adherence must be regularly monitored. Some aspects about post exposure prophylaxis and coinfection with HCV or HBV are discussed.

CONCLUSIONS

A higher level of evidence with regard to ART effectiveness and toxicity in pediatrics is currently available, leading to a more conservative and individualized approach. Clinical symptoms and CD4 count are the main determinants to start and change ART.

2NN Study Group, Kappelhoff BS, van Leth F, Robinson PA, MacGregor TR, Baraldi E, Montella F, Uip DE, Thompson MA, Russell DB, Lange JMA, Beijnen JH, Huitema ADR. Are Adverse Events of Nevirapine and Efavirenz Related to Plasma Concentrations?

Objective

The relationships between adverse events (AEs) and plasma concentrations of nevirapine (NVP) and efavirenz (EFV) were investigated as part of the large, international, randomized 2NN study.

Methods

Treatment-naive, HIV-1-infected patients received NVP (once or twice daily), EFV or their combination, each in combination with lamivudine and stavudine. Blood samples were collected on day 3 and weeks 1, 2, 4, 24 and 48. Concentrations of NVP and EFV were quantitatively assessed by a validated HPLC assay. Individual Bayesian estimates of the area under the plasma concentration–time curve over 24 h (AUC24h), and minimum and maximum plasma concentrations (Cmin and Cmax) as measures for drug exposure of NVP and EFV, were generated using a previously developed population pharmacokinetic model. Pharmacokinetic parameters were compared for patients with and without central nervous system (CNS) and psychiatric AEs, hepatic events, liver enzyme elevations (LEEs) and rash. Furthermore, it was investigated whether a clear cut-off for a pharmacokinetic parameter could be identified above which the incidence of AEs was clearly increased. AEs were also related to demographic parameters and baseline characteristics.

Results

In total, from 1077 patients, NVP (3024 samples) and EFV (1694 samples) plasma concentrations and AE data (825 observations) were available. For all patients Cmin, Cmax and AUC24h were determined. When corrected for known covariates of gender, CD4 cell count at baseline, region, hepatitis coinfection and possible interactions between these factors, no significant associations between AEs and any tested exposure parameter of NVP was observed. Also, no target Cmin value, above which patients were at increased risk for AEs, could be established. On the other hand, geographical region, hepatitis coinfection, CD4 cell count and gender were found to be significantly related with the incidence of CNS and psychiatric AEs, hepatic events, LEEs and rash during the treatment with NVP. The occurrence of elevated liver enzymes during the first 6 weeks in the EFV-containing arm was significantly ( P=0.036) correlated to the exposure of EFV (Cmin). Only hepatitis coinfection impacted on LEEs during the first 6 weeks of treatment. With an EFV Cmin above 2.18 mg/l during the induction phase, patients were 4.4 (range 1.3–15.5) times more at risk for elevated liver enzymes. No other correlations between AEs and EFV pharmacokinetics or patient characteristics could be identified.

Conclusions

Pharmacokinetic parameters of NVP did not have a relationship to AEs in the 2NN trial when corrected for known covariates. The value of periodical drug monitoring of NVP as a way to prevent toxicity is therefore limited. Treating physicians should instead focus on factors that are more predictive of AEs (gender, CD4 count and hepatitis coinfection). High EFV Cmin levels resulted in elevated liver enzyme values during the first 6 weeks of treatment. Regular measurement of EFV levels and liver enzymes at the start of therapy may therefore be advised.

Low-doses of indinavir boosted with ritonavir in HIV-infected Thai patients: pharmacokinetics, efficacy and tolerability

OBJECTIVES

To assess the steady-state pharmacokinetics of two reduced doses of indinavir boosted with ritonavir (indinavir/ritonavir) in HIV-infected Thai patients.

PATIENTS AND METHODS

Thirteen immunocompromised antiretroviral-naive patients (6 males, 7 females) initiated 600/100 mg indinavir/ritonavir, zidovudine and lamivudine, every 12 h. After 1 month, blood samples were taken at pre-dose, and 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 8 and 12 h after drug intake. Indinavir dosing was then reduced to 400 mg (twice daily) and 1 week later an identical series of samples were drawn. Patients then resumed 600 mg of indinavir. HIV-1 RNA viral load was determined at 8, 24 and 48 weeks. Indinavir plasma levels were determined by HPLC and pharmacokinetic parameters by non-compartmental analysis.

RESULTS

Median (range) weight was 58 kg (51-73) for men and 53 kg (46-59) for women. On 600 mg of indinavir, median indinavir AUC, C(max), and C(min) were 39.3 mg.h/L (20.6-50.5), 6.2 mg/L (3.7-9.0) and 0.41 mg/L (0.12-0.77), respectively, and on indinavir 400 mg, 18.3 mg.h/L (11.1-33.0), 3.8 mg/L (2.2-7.8) and 0.17 mg/L (0.10-0.39), respectively. No renal complications were observed. At 48 weeks, 6/13 (46%) patients had stopped 600 mg of indinavir due to intolerability (gastrointestinal and cutaneous), and 5/7 (71%) patients had a HIV-1 viral load <50 copies/mL.

CONCLUSIONS

Reduced doses of indinavir/ritonavir maintained adequate indinavir plasma levels compared to current guidelines suggesting that these doses are efficacious in this setting. Considering the poor tolerability of 600 mg of indinavir, the 400 mg of indinavir may be preferred due to its lower exposure indices but long-term efficacy data are needed.

Therapies for HIV and viral hepatitis coinfection

The natural history of chronic viral hepatitis is altered by HIV coinfection. Liver fibrosis rates and clinical features of liver disease develop more rapidly. Although HIV-hepatitis C virus coinfected subjects may progress more rapidly to AIDS, this is probably explained by comorbid illness, substance abuse and socioeconomic circumstances. Safe and virologically active treatment of HIV-hepatitis B virus coinfection can be concurrently achieved by the use of highly active antiretroviral therapy regimens containing lamivudine and/or tenofovir. In most cases, highly active antiretroviral therapy represents the most beneficial initial pharmaceutical intervention for HIV-hepatitisC virus coinfection. HepatitisC virus antiviral therapy should, in most cases, be reserved for those achieving HIV RNA suppression and immune restoration from highly active antiretroviral therapy or with nadir CD4 T-lymphocytes above 350 cells/microl.

Discordant Conclusions from HIV Clinical Trials — An Evaluation of Efficacy Endpoints

The three main components of long-term efficacy for a combination of antiretrovirals are: (i) the strength of the antiviral effect, (ii) toxicity profile and (iii) patient acceptability of the regimen. Intent-to-treat (ITT) analysis, where discontinuations and switches are considered failures [ITT, switch equals failure (ITT/S=F)], is a regulatory standard for analysing the efficacy of anti-retrovirals. A review of all clinical trials published in FDA product labels was conducted, including all clinical trials of boosted protease inhibitor- or nucleoside reverse transcriptase inhibitor-based highly active antiretroviral therapy in treatment-naive patients, and all clinical trials of antiretrovirals in treatment-experienced patients. Clinical trials where the results are presented in the standard ITT/S=F method were included. For randomized clinical trials in treatment-naive patients, the majority of treatment discontinuations have been either for toxicity (32%) or patient refusal of treatment (41%), with only 27% of failure endpoints for virological reasons among recent clinical trials in naive patients. Therefore, there is the potential for the results from ITT/S=F analysis to be driven by non-virological endpoints – a new treatment can be classified as ‘more efficacious’ than control owing to fewer discontinuations due to adverse events or patient preference.

In order to understand the intrinsic potency of the anti-retroviral regimen under study, ITT analysis needs to be supplemented by standardized as-treated analyses, excluding withdrawals for toxicity or other reasons. To evaluate the efficacy of a treatment strategy or sequential treatment regimens, the ‘ITT, switch included’ (ITT/SI) method: where changes from the initial randomized treatment are not classified as treatment failure – can be used. However, interpretation of clinical trials using ITT/SI analysis is difficult and depends on the frequency of treatment switching in the different arms of a trial.

Conclusions on efficacy from clinical trials can depend on the primary analysis used; most commonly, treatments could be significantly different by ITT/S=F analysis, but then interpreted as equivalent using the ITT/SI or as-treated methods.

Strategies for initiating combination antiretroviral therapy

Numerous potent antiretroviral regimens have proven successful as initial therapy in treatment-naive HIV-infected patients. As the development of new agents makes possible new treatment regimens, providers are faced with increasingly complex questions of when to initiate treatment and which regimen to select for individual patients. Clinical trial data provide a foundation for choosing an initial regimen and play a key role in the formation of treatment guidelines issued by the United States Public Health Service and other organizations. This paper reviews the results of recent clinical trials focusing on initial therapy and addresses important considerations when beginning antiretroviral therapy (ART) in treatment-naive individuals.

Adverse effects of antiretroviral therapy for HIV infection: a review of selected topics

In the current era of HIV treatment, the toxicity profiles of antiretroviral drugs have increasingly emerged as a basis for selecting initial antiretroviral regimens as well as a reason for switching therapy in treatment-experienced patients. In this respect, an intensive research effort involving clinical research as well as basic science research over the past six years, has focused on the cluster of metabolic and body composition abnormalities that have come to be termed the 'lipodystrophy syndrome'. These data have now provided a clear and clinically relevant understanding of the individual profiles of drugs within the nucleoside analogue reverse transcriptase inhibitor , HIV protease inhibitor and non-nucleoside analogue reverse transcriptase inhibitor drug classes, and have provided a rational basis for assessing and monitoring these adverse effects in clinical practice. In this review, current and emerging drug toxicities are considered with an emphasis on lipodystrophy complications.

The effect of baseline CD4 cell count and HIV-1 viral load on the efficacy and safety of nevirapine or efavirenz-based first-line HAART

BACKGROUND

A substantial number of patients start their first-line antiretroviral therapy at an advanced stage of an HIV-1 infection. Potential differences between specific drug regimens in antiviral efficacy and safety in these patients are of major importance.

METHODS

A post-hoc analysis within the randomized controlled 2NN trial comparing efficacy between regimes containing nevirapine (NVP), efavirenz (EFV), or both, in addition to stavudine and lamivudine.

PRIMARY OUTCOME

risk of virologic failure in different strata of baseline CD4 T-lymphocyte counts and plasma HIV-1 RNA concentrations (pVL). Virologic failure: never reaching a pVL < 400 copies/ml, or a rebound to two consecutive values > 400 copies/ml.

RESULTS

The risk of virologic failure was increased at very low CD4 counts (< 25 x 10(6) cells/l) compared to CD4 counts > 200 x 10(6) cells/l [hazard ratio (HR), 1.28; 95% confidence interval (CI), 0.93-1.77]. The same was seen for a pVL > or = 100,000 copies/ml compared to a lower pVL (HR, 1.20; CI, 0.96-1.50). There were no statistically significant differences between NVP and EFV in risk of virologic failure within any of the CD4 or pVL strata, although EFV performed slightly better in the low CD4 stratum. The incidence of rash in the NVP group was significantly higher in female patients with higher CD4 cell counts, while adverse events in the EFV group were not associated with CD4 cell count.

CONCLUSIONS

Initial antiretroviral therapy including NVP or EFV is effective in patients with an advanced HIV-1 infection. A high baseline CD4 cell count is associated with the occurrence of rash in female patients using NVP.

Rapid viral load suppression following generic highly active antiretroviral therapy in Southern Indian HIV-infected patients

We prospectively studied the initial results of 6 months of generic efavirenz-based therapy on the plasma viral load in 40 patients at YRG Centre for AIDS Research and Education, a tertiary HIV referral centre in southern India. The median baseline plasma viral load was 259,000 copies/ml and at 6 months 95% of patients had plasma viral loads less than 400 copies/ml. The data support the use of generic non-nucleoside reverse transcriptase inhibitor-based regimens in resource-limited settings.

Generic antiretroviral efficacy in AIDS-associated Kaposi's sarcoma in sub-Saharan Africa

Generic antiretroviral drugs are pivotal in the implementation of WHO's '3 by 5' programme. However, clinical experience with generics in sub-Saharan Africa is insufficiently documented. We report on 50 patients with HIV-associated Kaposi's sarcoma treated with generic fixed-dose highly active antiretroviral therapy. At 52 weeks, 74% achieved an undetectable viral load of < 50 copies/ml, 86% achieved < 400 copies/ml, and a 3.1 log10 decline from baseline. Side-effects were minimal. The outcomes support the use of generic antiretroviral therapy.

Field Assessment of Generic Antiretroviral Drugs: A Prospective Cohort Study in Cameroon

Objective

To assess the effectiveness of generic anti-retroviral drugs in terms of survival and virological and immunological responses, as well as their tolerability and the emergence of viral resistance.

Methods

A total of 109 HIV-1-infected patients were enrolled in a prospective cohort study in Yaoundé, Cameroon. Available generic drugs were a fixed-dose combination (FDC) of zidovudine (ZDV) and lamivudine (3TC), an FDC of 3TC, stavudine (d4T) and nevirapine (NVP), and individual formulations of ZDV, 3TC and NVP.

Results

At baseline, the median CD4 cell count was 150/mm3 [interquartile range (IQR) 61–223] and median viral load was 5.4 log10 copies/ml (IQR 4.8–5.6); 78% of patients received ZDV/3TC/NVP and 22% received 3TC/d4T/NVP. Median follow-up was 16 months (IQR 11–23). The survival probability was high (0.92 at 12 months); plasma viral load declined by a median of 3.3 log10 copies/ml and 86.9% of the intention-to-treat population had viral load <400 copies/ml at 12 months; CD4 count had increased by a median of 106 cells/mm3 at 12 months; drug resistance rarely emerged (incidence rate 3.2 per 100 person-years); and the treatments were reasonably well-tolerated (incidence rate of severe adverse effects 7.8 per 100 person-years).

Conclusion

Together with previous pharmacological and clinical studies, this prospective study suggests that these generic antiretroviral drugs can be used in developing countries.

Incidence and risk factors for rash in Thai patients randomized to regimens with nevirapine, efavirenz or both drugs

OBJECTIVE

To determine the incidence and risk factors for rash in Thai patients taking four different non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimens.

METHODS

HIV-positive, antiretroviral-naive patients enrolled in the 2NN study in Thailand and followed for at least 1 week were included. Patients were randomized to efavirenz (EFV) 600 mg once daily (OD) versus nevirapine (NVP) 200 mg twice daily (BD) versus NVP 400 mg OD versus NVP 400 mg OD + EFV 800 mg OD with stavudine/lamivudine.

RESULTS

Of 202 patients, 95 (47%) and 69 (34.2%) developed a rash from all reasons and from NNRTI, respectively. For NNRTI-related rash the incidences were EFV (20%), NVP BD (21%), NVP OD (38%) and NVP + EFV (67%). The proportions of patients with grade I, II and III within the four treatment arms are as follows: EFV, 4.3, 13 and 2.9%; NVP BD, 2.3, 15.9 and 2.3%; NVP OD, 12.8, 19.1 and 6.4%; and NVP + EFV, 11.9, 47.6 and 7.1%. Multivariate analyses showed females with CD4 cell count > or =250 x 10 cells/l, high body mass index (>21.3 kg/m), and a rise in CD4 (> or =53 x 10 cells/l) and alanine aminotransferase (ALT) (> or =34 U/l) at week 4 to be risk factors for rash.

CONCLUSIONS

Thai patients had a high incidence of NNRTI-related rash when treated with NVP + EFV or NVP OD. NVP if used BD had the same rash incidence as EFV for rash of all grades. Females, and persons with earlier HIV disease or with a large rise in CD4+ cell count after starting therapy are at greater risk for NNRTI-related rash.

Atazanavir for the treatment of human immunodeficiency virus infection

Atazanavir is the first once-daily protease inhibitor for the treatment of human immunodeficiency virus type 1 infection and should be used only in combination therapy, as part of a highly active antiretroviral therapy (HAART) regimen. In addition to being the most potent protease inhibitor in vitro, atazanavir has a distinct cross-resistance profile that does not confer resistance to other protease inhibitors. However, resistance to other protease inhibitors often confers clinically relevant resistance to atazanavir. Currently, atazanavir is not a preferred protease inhibitor for initial HAART regimens. In treatment-naive patients, atazanavir can be given as 400 mg/day. However, atazanavir should be pharmacologically boosted with ritonavir in treatment-experienced patients or when coadministered with either tenofovir or efavirenz. Patients who receive atazanavir experience similar rates of adverse events compared with patients receiving comparator regimens. An exception is an increased risk of asymptomatic hyperbilirubinemia, which is due to competitive inhibition of uridine diphosphate-glucuronosyltransferase 1A1. Although hyperbilirubinemia is a common adverse drug reaction of atazanavir therapy (22-47%), fewer than 2% of patients discontinue atazanavir therapy because of this adverse effect. Common adverse effects reported with atazanavir include infection, nausea, vomiting, diarrhea, abdominal pain, headache, peripheral neuropathy, and rash. Of significance, fewer abnormalities have been observed in plasma lipid profiles in patients treated with atazanavir compared with other protease inhibitor-containing regimens. As with other protease inhibitors, atazanavir is also a substrate and moderate inhibitor of the cytochrome P450 (CYP) system, in particular CYP3A4 and CYP2C9. Clinically significant drug interactions include (but are not limited to) antacids, proton pump inhibitors, histamine type 2 receptor antagonists, tenofovir, diltiazem, irinotecan, simvastatin, lovastatin, St. John's wort, and warfarin. We conclude that atazanavir is a distinctively characteristic protease inhibitor owing to its in vitro potency, once-daily dosing, distinct initial resistance pattern, and infrequent association with metabolic abnormalities.

Do Non-Nucleoside Reverse Transcriptase Inhibitors Contribute to Lipodystrophy?

Lipodystrophy complications, including lipoatrophy (pathological fat loss) and metabolic complications, have emerged as important long-term toxicities associated with antiretroviral therapy in the current era. The wealth of data that has accumulated over the past 6 years has now clarified the contribution of specific antiretroviral drugs to the risk of these clinical endpoints, with evidence that lipoatrophy is strongly associated with the choice of nucleoside reverse transcriptase inhibitor therapy (specifically, stavudine and to a lesser extent zidovudine). The aetiological basis of metabolic complications of antiretroviral therapy has proven to be complex, in that the risk appears to be modulated by a number of lifestyle factors that have made the metabolic syndrome highly prevalent in the general population, with additional contributions from HIV disease status itself, as well as from individual drugs within the HIV protease inhibitor class. The currently licensed non-nucleoside reverse transcriptase inhibitor (NNRTI) drugs, efavirenz and nevirapine, have been proven to have a favourable safety profile in terms of lipodystrophy complications. However, it must be noted that NNRTI drugs also have individual toxicity profiles that must be accounted for when considering and/or monitoring their use in the treatment of HIV infection.

Antiretroviral Therapy in the??Real World

OBJECTIVE AND METHODS

The aim of our study was to analyse retrospectively the nature and frequency of antiretroviral prescriptions for 990 HIV-infected patients followed at our outpatient centre in Bologna, Italy, from January 2003 to March 2004. The main focus of the study was to identify the most commonly prescribed combinations and their related expenses, in order to identify the most competitive treatment regimens with regard to costs. Prescriptions were given directly to patients at monthly intervals, and drug treatment adherence data was stored in an electronic database. Antiretroviral regimens administered for the longest period to each patient during the 15 months of the study were selected for the study. All patients treated for <9 consecutive months and/or with treatment adherence levels <90% were excluded. Physicians assessed antiretroviral therapy at least quarterly according to efficacy and safety criteria, but not in terms of pharmacoeconomic considerations. Direct pharmacy expenses were obtained for the 24 most commonly used therapeutic regimens, covering 80.1% of patients.

RESULTS

The zidovudine-lamivudine-efavirenz combination proved to be the most prescribed combination (7.3%), followed by zidovudine-lamivudine- nevirapine (7.1%), lamivudine-stavudine (6.2%), zidovudine-lamivudine- lopinavir-ritonavir (5.2%), didanosine-stavudine-lopinavir-ritonavir (4.8%), and lamivudine-stavudine-nevirapine (4.7%). Anti-HIV combinations varied from a minimum yearly cost of euro3895.6 for lamivudine-stavudine to euro9422.8 for the zidovudine-lamivudine-lopinavir-ritonavir combination (+241.9%) [year of costing 2003]. There was a significant difference between the two first-line regimens for antiretroviral-naive subjects, with lopinavir-ritonavir-based combinations costing more than euro9000 per patient/year compared with efavirenz-containing combinations, which were 28% less expensive. Mean daily costs varied substantially, from a minimum of euro10.7 per day for lamivudine-stavudine to a maximum of euro25.8 per day (+241.1%) for zidovudine-lamivudine-lopinavir-ritonavir. Regimens based on non-nucleoside reverse transcriptase inhibitors (NNRTIs) were less costly than most of those including protease inhibitors (PIs). The increased expense of each combination was compared with the cheapest therapeutic selection (lamivudine-stavudine), and costs of all triple combinations were also compared. Regimens based on NNRTIs accounted for 29.3% of our cohort (nevirapine-containing therapies 15.1%, and efavirenz-based ones 14.2%), while PIs were used in the majority of cases (37.3%), with lopinavir-ritonavir as the leading combination (13.6% of patients), followed by nelfinavir (9.9%) and indinavir (9.2%). When drug-related costs were examined, dual nucleoside analogues showed the lowest expense (euro10.7-euro11.6 per day), while triple nucleoside/nucleotide analogue combinations cost nearly twice as much (euro18.5-euro20.4 per day). Among the NNRTIs, there were comparable costs for nevirapine-based combinations (euro18.3-euro18.7 per day), while efavirenz-including regimens were 10% more costly (euro19.2-euro20.l per day). A very broad range of combinations and related costs were found with PIs, but apart from indinavir and saquinavir combinations (euro15.7-euro21.7 per day), all other regimens had a higher daily cost (from euro22.0 per day for ritonavir-based regimens to euro23.4-euro24.3 per day for nelfinavir combinations, and up to euro24.9-euro25.8 per day with lopinavir-ritonavir). When considering nelfinavir- and lopinavir-containing combinations, the difference compared with NNRTI-based regimens varied from 41% when nevirapine- and lopinavir-ritonavir were compared, to 11.6% when efavirenz and nelfinavir were compared.

CONCLUSIONS

Investigations that link prescribing patterns and related costs in the setting of HIV disease therapy are needed to improve patient management and help with the planning of healthcare resource allocation.

Kappelhoff BS, van Leth F, MacGregor TR, Lange JMA, Beijnen JH, Huitema ADR. Nevirapine and Efavirenz Pharmacokinetics and Covariate Analysis in the 2Nn Study

Objective

The aim of this 2NN pharmacokinetic substudy was to investigate the population pharmacokinetics of nevirapine and efavirenz.

Methods

Treatment-naive, HIV-1-infected patients received nevirapine (once or twice daily), efavirenz or a combination with lamivudine and stavudine. Blood samples were collected on day 3 and weeks 1, 2, 4, 24 and 48. Using non-linear mixed effects modelling, pharmacokinetics of nevirapine and efavirenz and factors involved in the inter-individual variability were investigated.

Results

Clearance of nevirapine in the induction phase (<14 days) and at steady state (>28 days) were 2.02 l/h and 2.81 l/h, respectively. Volume of distribution and absorption rate constant were 77.0 l and 1.66 h-1, respectively. Clearance of nevirapine was lower in females (13.8%) and in patients with hepatitis B (19.5%). Patients from South America and Western countries had higher clearance of nevirapine compared with Thai and South African patients. The clearances of efavirenz in the induction phase and at steady state were 7.95 l/h and 8.82 l/h, respectively. The volume of distribution and absorption rate constant were 418 l and 0.287 h-1, respectively. Concomitant use of nevirapine increased clearance of efavirenz (43%). Patients from Thailand had lower clearance than the rest of the population.

Conclusions

The population pharmacokinetics of nevirapine and efavirenz were assessed in the 2NN trial. For both drugs, an induction phase was distinguished from the steady-state phase. Gender, hepatitis B and geographical region were involved in the variability of the pharmacokinetics of nevirapine. Region and concomitantly used nevirapine were determinants of the pharmacokinetics of efavirenz.

Efavirenz for HIV-1 infection in adults: an overview

Efavirenz (Sustiva), Bristol-Myers Squibb) is a non-nucleoside reverse transcriptase inhibitor that has been used successfully since the late 1990s to treat HIV-1 infection, and has since become a cornerstone of antiretroviral therapy. The efficacy and potency of efavirenz has been established in many clinical trials and cohort studies, where it has been compared with unboosted or ritonavir (Norvir, Abbott Laboratories Ltd)-boosted protease inhibitors, nevirapine (Viramune, Boehringer Ingelheim Ltd); and three nucleoside analog-based regimens. Pharmacokinetics allowing for a convenient once-daily administration make efavirenz one of the first agents to be included in once-daily regimens. Tolerability of efavirenz is satisfactory, although CNS-related toxicity can occur, and is still poorly understood. New insights into the pharmacokinetics of efavirenz could help to manage this unwanted toxicity. This drug profile will examine the principal data concerning the efficacy, pharmacokinetics and safety that have made efavirenz a standard of care in HIV-1 therapy, and will comment on new data that could change the way efavirenz is used in the near future.

Nevirapine and efavirenz elicit different changes in lipid profiles in antiretroviral-therapy-naive patients infected with HIV-1

BACKGROUND

Patients infected with HIV-1 initiating antiretroviral therapy (ART) containing a non-nucleoside reverse transcriptase inhibitor (NNRTI) show presumably fewer atherogenic lipid changes than those initiating most ARTs containing a protease inhibitor. We analysed whether lipid changes differed between the two most commonly used NNRTIs, nevirapine (NVP) and efavirenz (EFV).

METHODS AND FINDINGS

Prospective analysis of lipids and lipoproteins was performed in patients enrolled in the NVP and EFV treatment groups of the 2NN study who remained on allocated treatment during 48 wk of follow-up. Patients were allocated to NVP (n = 417), or EFV (n = 289) in combination with stavudine and lamivudine. The primary endpoint was percentage change over 48 wk in high-density lipoprotein cholesterol (HDL-c), total cholesterol (TC), TC:HDL-c ratio, non-HDL-c, low-density lipoprotein cholesterol, and triglycerides. The increase of HDL-c was significantly larger for patients receiving NVP (42.5%) than for patients receiving EFV (33.7%; p = 0.036), while the increase in TC was lower (26.9% and 31.1%, respectively; p = 0.073), resulting in a decrease of the TC:HDL-c ratio for patients receiving NVP (-4.1%) and an increase for patients receiving EFV (+5.9%; p < 0.001). The increase of non-HDL-c was smaller for patients receiving NVP (24.7%) than for patients receiving EFV (33.6%; p = 0.007), as were the increases of triglycerides (20.1% and 49.0%, respectively; p < 0.001) and low-density lipoprotein cholesterol (35.0% and 40.0%, respectively; p = 0.378). These differences remained, or even increased, after adjusting for changes in HIV-1 RNA and CD4+ cell levels, indicating an effect of the drugs on lipids over and above that which may be explained by suppression of HIV-1 infection. The increases in HDL-c were of the same order of magnitude as those seen with the use of the investigational HDL-c-increasing drugs.

CONCLUSION

NVP-containing ART shows larger increases in HDL-c and decreases in TC:HDL-c ratio than an EFV-containing regimen. Based on these findings, protease-inhibitor-sparing regimens based on non-nucleoside reverse transcriptase inhibitor, particularly those containing NVP, may be expected to result in a reduced risk of coronary heart disease.

Fibrates or statins and lipid plasma levels in 245 patients treated with highly active antiretroviral therapy. Aquitaine Cohort, France, 1999-2001

OBJECTIVES

To describe the effect and tolerance of lipid-lowering drugs (LLD; fibrates and statins) in patients treated with highly active antiretroviral therapy (HAART).

METHODS

A prospective study was performed in a large cohort of HAART-treated HIV-infected patients using guidelines for case management of dyslipidaemia. Inclusion criteria were: age over 18 years; HIV infection treated with HAART including at least one protease inhibitor (PI) or nonnucleoside reverse transcriptase inhibitor (NNRTI); total cholesterol (TC)>5.5 mmol/L and/or triglycerides (TG)>2.2 mmol/L; and initiation of fibrates or statins. Viral load, CD4 cell count, plasma lipid levels and liver enzymes were measured at baseline (M0) and 3(M3) and 12(M12) months thereafter. Muscular enzymes were not assessed.

RESULTS

Fibrates were prescribed to 179 patients and statins to 66 patients. There was a significant mean decrease of TG in the fibrates group between M0 and M3 [-2.29 mmol/L; 95% confidence interval (CI)=-3.53, -1.05; P<10(-4)] and between M0 and M12 (-2.25 mmol/L; 95% CI:-4.23, -0.29; P<10(-4)); a significant decrease of TC was also noticed between M0 and M3 (-0.55 mmol/L; 95% CI:-0.95, -0.15; P=0.008) but not at M12 (-0.33 mmol/L; 95% CI:-0.94, 0.26; P=0.27). In the statins group, TC significantly decreased between M0 and M3 (-0.78 mmol/L; 95% CI:-1.3, -0.27; P=0.004) and between M0 and M12 (-0.70 mmol/L; 95% CI:-1.31, -0.09; P=0.03). There was no significant difference between the decreases of TG or TC observed in patients treated with PI or NNRTI. There were no significant modifications of viral load, CD4 cell count or liver enzymes during the 12 months of followup.

CONCLUSIONS

In this HAART-treated cohort, fibrates and statins were safe and associated with a favourable but moderate effect on lipid plasma levels.

Effectiveness and safety of a generic fixed-dose combination of nevirapine, stavudine, and lamivudine in HIV-1-infected adults in Cameroon: open-label multicentre trial

BACKGROUND

Generic fixed-dose combinations have been prequalified by WHO to treat HIV-infected patients in resource-limited countries. Despite their widespread use they are, however, not yet recommended by some of the major donor agencies owing to scarcity of clinical data on effectiveness, safety, and quality. We aimed to assess these issues for one of the most frequently prescribed treatments in Africa, a generic fixed-dose combination of nevirapine, stavudine, and lamivudine.

METHODS

60 patients were followed in an open-label, 24-week multicentre trial in Cameroon. All patients received one tablet of the fixed-dose combination drug twice daily. The primary outcome measure was the proportion of patients with viral load less than 400 copies per mL at the end of the study period, in an intention-to-treat analysis.

FINDINGS

At baseline, 92% of patients (n=55) had AIDS; median CD4 count was 118 cells per microL (IQR 78-167) and median plasma HIV-1 RNA was 104?736 copies per mL (40804-243787). The proportion of patients with undetectable viral load (<400 copies per mL) after 24 weeks of treatment was 80% (95% CI 68-89). Median (IQR) change in viral load was -3.1 log10 copies per mL (-2.5 to -3.6) and in CD4 count 83 cells per microL (40-178). The probability of remaining alive or free of new AIDS-defining events was 0.85 (95% CI 0.73-0.92). Frequency of disease progression was 32.0 (95% CI 16.6-61.5), severe adverse effects 17.8 (7.4-42.7), and genotypic resistance mutations 7.1 (1.8-28.4) per 100 person-years. Mean reported adherence rate was 99%. Median drug concentrations in tablets were 96% of expected values for nevirapine, 89% for stavudine, and 99% for lamivudine.

INTERPRETATION

Our findings lend support to use and funding of a generic fixed-dose combination of nevirapine, stavudine, and lamivudine as first-line antiretroviral treatment in developing countries.

Quality of Life in Patients Treated with First-Line Antiretroviral Therapy Containing Nevirapine And/Or Efavirenz

Objective

To assess whether differences in safety profiles between nevirapine (NVP) and efavirenz (EFV), as observed in the 2NN study, translated into differences in ‘health related quality of life’ (HRQoL).

Design

A sub-study of the 2NN study, with antiretro-viral-naive patients randomly allocated to NVP (once or twice daily), EFV or NVP+EFV, in addition to stavudine and lamivudine.

Methods

Comparing differences in changes of HRQoL over 48 weeks as measured with the Medical Outcomes Study HIV Health Survey (MOS-HIV) questionnaire, using analysis of variance.

Results

The 2NN study enrolled 1216 patients. No validated questionnaires were available for 244 patients, and 55 patients had no HRQoL data at all, leaving 917 patients eligible for this sub-study. A total of 471 (51%) had HRQoL measurements both at baseline and week 48. The majority (69%) of patients without HRQoL measurements did, however, complete the study. The change in the physical health score (PHS) was 3.9 for NVP, 3.4 for EFV and 2.4 for NVP+EFV ( P=0.712). For the mental health score (MHS) these values were 6.1, 7.0 and 3.9, respectively ( P=0.098). A baseline plasma HIV-1 RNA concentration (pVL) ≥100 000 copies/ml and a decline in pVL (per log10) were independently associated with an increase of PHS. An increase of MHS was only associated with pVL decline. Patients experiencing an adverse event during follow-up had a comparable change in PHS but a significantly smaller change in MHS, compared with those without an adverse event.

Conclusions

First-line ART containing NVP and/or EFV leads to an improvement in HRQoL. The gain in HRQoL was similar for NVP and EFV, but slightly lower for the combination of these drugs.

Riesgo vascular en pacientes con infección crónica por el VIH-1: controversias con implicaciones terapéuticas, clínicas y pronósticas

Atherosclerosis increases cardiovascular risk and the possibility of developing acute myocardial infarction (AMI) or stroke. Patients infected with human immunodeficiency virus (HIV) often present morphological and metabolic alterations (hypercholesterolemia, hypertriglyceridemia, insulin resistance, diabetes) that can increase vascular risk. The frequent coexistence of classic risk factors (atherogenic diet, smoking, physical inactivity, cocaine abuse), the progressive increase in mean age of HIV-1 infected patients, and the polymedication they receive make it difficult to estimate the direct effect that new therapies may have on cardiovascular risk. Retrospective clinical studies with diverse designs in large cohorts offer contradictory results for cardiovascular risk in the HIV-infected population. Longer observational periods are needed and the effect of other classic risk factors needs to be controlled, in order to establish the possible detrimental effect the new therapies may have on cardiovascular risk in this population.