Long-term safety and efficacy of nevirapine-based approaches in HIV type 1-infected patients

Accuracy of measures for antiretroviral adherence in people living with HIV

BACKGROUND

Good patient adherence to antiretroviral (ART) medication determines effective HIV viral suppression, and thus reduces the risk of progression and transmission of HIV. With accurate methods to monitor treatment adherence, we could use simple triage to target adherence support interventions that could help in the community or at health centres in resource-limited settings.

OBJECTIVES

To determine the accuracy of simple measures of ART adherence (including patient self-report, tablet counts, pharmacy records, electronic monitoring, or composite methods) for detecting non-suppressed viral load in people living with HIV and receiving ART treatment.

SEARCH METHODS

The Cochrane Infectious Diseases Group Information Specialists searched CENTRAL, MEDLINE, Embase, LILACS, CINAHL, African-Wide information, and Web of Science up to 22 April 2021. They also searched the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and ClinicalTrials.gov for ongoing studies. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We included studies of all designs that evaluated a simple measure of adherence (index test) such as self-report, tablet counts, pharmacy records or secondary database analysis, or both, electronic monitoring or composite measures of any of those tests, in people living with HIV and receiving ART treatment. We used a viral load assay with a limit of detection ranging from 10 copies/mL to 400 copies/mL as the reference standard. We created 2 × 2 tables to calculate sensitivity and specificity.

DATA COLLECTION AND ANALYSIS

We screened studies, extracted data, and assessed risk of bias using QUADAS-2 independently and in duplicate. We assessed the certainty of evidence using the GRADE method. The results of estimated sensitivity and specificity were presented using paired forest plots and tabulated summaries. We encountered a high level of variation among studies which precluded a meaningful meta-analysis or comparison of adherence measures. We explored heterogeneity using pre-defined subgroup analysis.

MAIN RESULTS

We included 51 studies involving children and adults with HIV, mostly living in low- and middle-income settings, conducted between 2003 and 2021. Several studies assessed more than one index test, and the most common measure of adherence to ART was self-report. - Self-report questionnaires (25 studies, 9211 participants; very low-certainty): sensitivity ranged from 10% to 85% and specificity ranged from 10% to 99%. - Self-report using a visual analogue scale (VAS) (11 studies, 4235 participants; very low-certainty): sensitivity ranged from 0% to 58% and specificity ranged from 55% to 100%. - Tablet counts (12 studies, 3466 participants; very low-certainty): sensitivity ranged from 0% to 100% and specificity ranged from 5% to 99%. - Electronic monitoring devices (3 studies, 186 participants; very low-certainty): sensitivity ranged from 60% to 88% and the specificity ranged from 27% to 67%. - Pharmacy records or secondary databases (6 studies, 2254 participants; very low-certainty): sensitivity ranged from 17% to 88% and the specificity ranged from 9% to 95%. - Composite measures (9 studies, 1513 participants; very low-certainty): sensitivity ranged from 10% to 100% and specificity ranged from 49% to 100%. Across all included studies, the ability of adherence measures to detect viral non-suppression showed a large variation in both sensitivity and specificity that could not be explained by subgroup analysis. We assessed the overall certainty of the evidence as very low due to risk of bias, indirectness, inconsistency, and imprecision. The risk of bias and the applicability concerns for patient selection, index test, and reference standard domains were generally low or unclear due to unclear reporting. The main methodological issues identified were related to flow and timing due to high numbers of missing data. For all index tests, we assessed the certainty of the evidence as very low due to limitations in the design and conduct of the studies, applicability concerns and inconsistency of results.

AUTHORS' CONCLUSIONS

We encountered high variability for all index tests, and the overall certainty of evidence in all areas was very low. No measure consistently offered either a sufficiently high sensitivity or specificity to detect viral non-suppression. These concerns limit their value in triaging patients for viral load monitoring or enhanced adherence support interventions.

Long-term efficacy and safety of nevirapine-containing regimens in virologically suppressed patients: a 17-year follow up

Background: To evaluate long term outcomes in patients maintaining a NVP based regimen for more than 10 years.Materials and methods: Retrospective, multicenter, cohort study including virologically suppressed patients, currently receiving a NVP-based regimen that had been started at least 10 years previously. Demographic, clinical, and analytical variables were recorded.Results: Two hundred and seventy four subjects were included. Median (IQR) follow up was 17.1 (13.8-18.5) years. Dyslipidemia (29.9%), hypertension (11.4%) and diabetes (8%) were the most common reported co-morbidities. After a median of 17 years of follow-up we observed a significant increase in general health markers such as hemoglobin and CD4 cells (all p<0.001) as well as a significant reduction in CD8 and ALT [-111 cells/uL (-346.5-151) p 0.003 and ALT median (IQR) -4.2 (-18.5-4) p<0.001 respectively]. LDL-c and serum triglyceride levels decreased significantly [-0,1 (-1-0.6) p:<0.001 and -0,3 (-1.2-0.4) p:0.002 respectively]. HDL-c increased significantly 0.3 (00.5-0.6). Median (IQR) time with persistent HIV VL <50 copies was 16 (13-18) years. During follow up, subjects presented with median (IQR) 1 (0-2) blip (HIV VL >50<1000 copies/ml).Conclusions: Based on the extensive experience as well as a good tolerance and efficacy profile, NVP should be considered for treatment continuation in those patients already receiving this inexpensive generic drug.

Assessment of the nevirapine safety signal using data from the national antiretroviral dispensing database: a retrospective study

BACKGROUND

Clinical trials showed a higher risk of skin- and liver- related adverse reactions when NVP-based antiretroviral therapy (ART) was initiated in female and male patients with baseline CD4 cell counts ≥250 and ≥400, respectively. Some studies reported no difference in risk between the high and low CD4 count groups. Consequently, the use of NVP-based ART in all patients with a CD4 cell count <350, was recommended. In 2011, the Pharmacovigilance Centre detected an increase in reports of grade III and IV reactions. The center was required to determine if there was an increase in NVP-related reactions.

METHODS

Automated dispensing records from January 2008 to November 2011 were accessed from the National Antiretroviral Dispensing Database (NDB). Records of patients who were initiated on NVP-based ART were selected, and records showing a replacement of NVP with protease inhibitor (PI) were identified. The proportions of grade III and IV reactions were calculated per quarter, and Odds Ratios (OR) were calculated, with the confidence interval set at 95 % and a p-value of <0.05.

RESULTS

From 2008 to 2011 a total of 84,741 patients were started on ART. Of these 67,794 were initiated on NVP-containing ART. Of these, 211 females and 79 males were substituted from NVP to a PI. The OR for females was 2.4 (95 % confidence interval [CI] 1.8 - 3.1). For males the OR was 2.4 (OR 2.4; 95 % CI 1.4 - 3.8) which occurred nine months after the change observed in the females. The odds of a NVP-to-PI substitution in females compared to males before the launch of Namibia's 2010 ART guidelines was the same as the odds after the publication of the guidelines (before, OR 1.6; 95 % CI 1.1 - 2.5; after, OR 1.6; 95 % CI 1.2 - 2.2).

CONCLUSIONS

There was an increase in substitutions of NVP with a PI following the increase in the CD4 threshold for initiating NVP-based HAART, meaning that there was an increase in grade III and IV reactions associated with NVP. Therefore the NVP-safety signal was confirmed to be a true signal, which contributed to the Ministry's decision to review the use of NVP.

Effectiveness of a Treatment Switch to Nevirapine plus Tenofovir and Emtricitabine (or Lamivudine) in Adults with HIV-1 Suppressed Viremia

Background

Switching subjects with persistently undetectable HIV-1 viremia under antiretroviral treatment (ART) to once-daily tenofovir/emtricitabine (or lamivudine) + nevirapine is a cost-effective and well-tolerated strategy. However, the effectiveness of this approach has not been established.

Methods

We performed a retrospective study evaluating the rates of treatment failure, virological failure (VF), and variables associated, in all subjects initiating this switch combination in our clinic since 2001. Analyses were performed by a modified intention to treat, where switch due to toxicity equalled failure. The main endpoint was plasma HIV-RNA < 50 copies/mL.

Results

341 patients were treated for a median of 176 (57; 308) weeks. At week 48, 306 (89.7%) subjects had HIV-1 RNA <50 copies/mL, 10 (2.9%) experienced VF, and 25 (7.4%) discontinued the treatment due to toxicity. During the whole follow-up 23 (6.7%) individuals (17 on lamivudine, 6 on emtricitabine; p = 0.034) developed VF and treatment modification due to toxicity occurred in 36 (10.7%). Factors independently associated with VF in a multivariate analysis were: intravenous drug use (HR 1.51; 95%CI 1.12, 2.04), time with undetectable viral load before the switch (HR 0.98; 0.97, 0.99), number of prior NRTIs (HR 1.49; 1.15, 1.93) or NNRTIs (HR 3.22; 1.64, 6.25), and previous NVP (HR 1.54; 1.10, 2.17) or efavirenz (HR 5.76; 1.11, 29.87) unscheduled interruptions. VF was associated with emergence of usual nevirapine mutations (Y181C/I/D, K103N and V106A/I), M184V (n = 16; 12 with lamivudine vs. 4 with emtricitabine, p = 0.04), and K65R (n = 7).

Conclusions

The rates of treatment failure at 48 weeks, or long-term toxicity or VF with this switch regimen are low and no unexpected mutations or patterns of mutations were selected in subjects with treatment failure.

HLA Class I restricted CD8+ and Class II restricted CD4+ T cells are implicated in the pathogenesis of nevirapine hypersensitivity

OBJECTIVES

This study sought to examine nevirapine hypersensitivity (NVP HSR) phenotypes and their relationship with differing major histocompatibility complex (MHC) Class I and Class II alleles and the associated CD4 and CD8 T-cell NVP-specific responses and their durability over time.

METHODS

A retrospective cohort study compared HIV-positive patients with NVP HSR, defined by fever and hepatitis and/or rash, with those tolerant of NVP for more than 3 months. Covariates included class I (HLA-A, B, C) and class II (HLA-DR) alleles. Cellular studies examined NVP-specific CD4 and CD8 T-cell responses by interferon-gamma (IFNγ) ELISpot assay and intracellular cytokine staining (ICS).

RESULTS

NVP HSR occurred in 19 out of 451 (4%) NVP-exposed individuals between March 1993 and December 2011. HLA associations were phenotype dependent with HLA-DRB1*01 : 01 associated with hepatitis (P = 0.02); HLA-B*35 : 01 and HLA-Cw4 associated with cutaneous NVP HSR (P = 0.001, P = 0.01), and HLA-Cw*08 was associated with NVP HSR with eosinophilia (P = 0.04) and multisystemic NVP HSR (P = 0.02). NVP-specific INFγ responses waned significantly more than 3 months from the original reaction and were diminished or completely abrogated when either CD4 or CD8 T cells were depleted from the peripheral blood mononuclear cells culture.

CONCLUSION

The association of specific class I and II allele pairings with specific phenotypes of NVP HSR, and cellular studies showing both CD4 and CD8 T-cell NVP-specific responses suggest that specific combinations of NVP reactive class I restricted CD8 and class II restricted CD4 T cells contribute to the immunopathogenesis of NVP HSR.

HLA and pharmacogenetics of drug hypersensitivity

Immunologically mediated drug reactions have been traditionally classified as unpredictable based on the fact that they cannot be predicted strictly on the pharmacological action of the drug. Such adverse drug reactions are associated with considerable morbidity and include severe cutaneous adverse reactions such as Stevens-Johnson syndrome/toxic epidermal necrolysis and the drug hypersensitivity syndromes (drug reaction with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome). Over the last decade there have been many associations between these syndromes and Class I and II HLA alleles of the MHC, which have enriched and driven our knowledge of their immunopathogenesis. Significant translation has also occurred in the case of HLA-B*5701 screening being used to exclude at risk patients from abacavir and prevent abacavir hypersensitivity. The ultimate translation of the knowledge of how drugs interact with HLA would be applicable to preclinical drug screening programs to improve the safety and cost-effectiveness of drug design and development.

Evaluation of the safety and effectiveness of nevirapine plus coformulated tenofovir/emtricitabine as first-line therapy in routine clinical practice

Despite having demonstrated noninferior efficacy against atazanavir/ritonavir plus coformulated tenofovir/emtricitabine (cTDF/FTC), the combination of nevirapine plus cTDF/FTC is not included among preferred regimens in some international guidelines. This combination is frequently used in Spain. We analyzed its effectiveness and safety as first-line therapy in a routine clinical practice. A retrospective, multicenter study was performed in treatment-naive HIV-1-infected subjects who started nevirapine plus cTDF/FTC as first-line therapy according to the nevirapine CD4(+) cell count threshold. The primary endpoint was the proportion of subjects with plasma HIV-1 RNA <50 copies/ml at week 48. We included 123 subjects starting the regimen from 2005 to 2008. The median age was 41.0 years, the median baseline CD4(+) cell count was 215 cells/μl, the median plasma viral load (VL) was 4.83 log(10) copies/ml, and 22% had hepatitis C coinfection. At week 48, 96 subjects (78%; 95% CI: 69.9-84.4) had a VL <50 copies/ml in an ITT analysis, and the median rise in the CD4(+) cell count was 118 cells/μl. Virological failure was observed in 6.5% (8/123) of subjects, all them before week 24 and related to poor adherence. There was no relationship between virological failure and baseline CD4(+) cell count or VL. Ten percent (13/123) of the subjects discontinued the treatment due to adverse events. There was a significant decrease in total/HDL-cholesterol ratio (p=0.03) with an increase in HDL-cholesterol (p=0.01) over 48 weeks. The combination of nevirapine plus cTDF/FTC showed a high virological efficacy without unexpected toxicities as a first-line treatment in a routine clinical practice.

Morphological and metabolic components of lipodystrophy in various nevirapine-based highly active antiretroviral therapy (HAART) regimens: a cross-sectional, observational study

BACKGROUND

Morphological abnormalities (lipoatrophy and central fat accumulation) and metabolic changes (dyslipidaemia and glucose regulation impairment) have emerged as components of lipodystrophy and as major tolerability issues with long-term use of highly active antiretroviral therapy (HAART) in HIV-positive patients. Protease inhibitors (PIs) are recognized as having the greatest impact in terms of metabolic complications, followed by nucleoside reverse transcriptase inhibitors, while the non-nucleoside reverse transcriptase inhibitors (NNRTIs) have the least impact. In particular, regimens based on the NNRTI nevirapine have been shown to achieve significant metabolic benefits and may help to improve dyslipidaemia. Improvements in body shape changes associated with lipodystrophy have also been reported when nevirapine replaced a PI in long-term triple therapy.

OBJECTIVE

The objective of this cross-sectional observational ('real-world') study was to investigate the effect of three HAART regimens plus stable nevirapine therapy on morphological and metabolic components of lipodystrophy in HIV-infected patients.

METHODS

Consecutive patients (aged >18 years) with serologically documented HIV infection, who had received HAART for at least 2 years and who had been diagnosed with lipodystrophy, were followed up as outpatients at the metabolic clinic of the University of Modena and Reggio Emilia, Modena, Italy. Patients received stable nevirapine therapy plus fixed-dose combinations of tenofovir disoproxil fumarate plus emtricitabine (Truvada(®); TVD), zidovudine plus lamivudine (3TC) [Combivir(®); CBV], or abacavir plus lamivudine (Kivexa(®); KVX). Multivariate regression analyses were performed to analyse predictors of four components of lipodystrophy: lipoatrophy using leg fat mass measured by dual-emission x-ray absorptiometry (DXA), fat accumulation using waist circumference, dyslipidaemia using apolipoprotein (Apo)B/ApoA1 ratio, and glucose intolerance using the Homeostasis Model Assessment for Insulin Resistance (HOMA-IR).

RESULTS

Overall, 101 patients were enrolled (TVD group = 61, CBV group = 20, KVX group = 20); 191 observations were analysed. Male sex was associated with reduced leg fat mass, while age and body mass index (BMI) were associated with increased leg fat mass (all p < 0.05). Leg fat mass and male sex were associated with increased waist circumference (p < 0.001 for both). Leg fat mass predicted reduced ApoB/ApoA1 ratio, while age and BMI predicted increased ApoB/ApoA1 ratio (all p < 0.05). BMI predicted HOMA-IR increase (p = 0.0017). No differences in lipoatrophy, central fat accumulation, dyslipidaemia or glucose metabolism were observed among any of the three different nevirapine plus nucleoside backbone groups (TVD, CBV or KVX).

CONCLUSION

HAART including nevirapine has a limited impact on components of lipodystrophy in patients with HIV infection. Further studies are needed to verify if nevirapine overcomes the expected distinct lipodystrophy risk profile associated with different nucleoside backbone therapies.

Morphological and metabolic components of lipodystrophy in various nevirapine-based highly active antiretroviral therapy (HAART) regimens: a cross-sectional, observational study

BACKGROUND

Morphological abnormalities (lipoatrophy and central fat accumulation) and metabolic changes (dyslipidaemia and glucose regulation impairment) have emerged as components of lipodystrophy and as major tolerability issues with long-term use of highly active antiretroviral therapy (HAART) in HIV-positive patients. Protease inhibitors (PIs) are recognized as having the greatest impact in terms of metabolic complications, followed by nucleoside reverse transcriptase inhibitors, while the non-nucleoside reverse transcriptase inhibitors (NNRTIs) have the least impact. In particular, regimens based on the NNRTI nevirapine have been shown to achieve significant metabolic benefits and may help to improve dyslipidaemia. Improvements in body shape changes associated with lipodystrophy have also been reported when nevirapine replaced a PI in long-term triple therapy.

OBJECTIVE

The objective of this cross-sectional observational ('real-world') study was to investigate the effect of three HAART regimens plus stable nevirapine therapy on morphological and metabolic components of lipodystrophy in HIV-infected patients.

METHODS

Consecutive patients (aged >18 years) with serologically documented HIV infection, who had received HAART for at least 2 years and who had been diagnosed with lipodystrophy, were followed up as outpatients at the metabolic clinic of the University of Modena and Reggio Emilia, Modena, Italy. Patients received stable nevirapine therapy plus fixed-dose combinations of tenofovir disoproxil fumarate plus emtricitabine (Truvada(®); TVD), zidovudine plus lamivudine (3TC) [Combivir(®); CBV], or abacavir plus lamivudine (Kivexa(®); KVX). Multivariate regression analyses were performed to analyse predictors of four components of lipodystrophy: lipoatrophy using leg fat mass measured by dual-emission x-ray absorptiometry (DXA), fat accumulation using waist circumference, dyslipidaemia using apolipoprotein (Apo)B/ApoA1 ratio, and glucose intolerance using the Homeostasis Model Assessment for Insulin Resistance (HOMA-IR).

RESULTS

Overall, 101 patients were enrolled (TVD group = 61, CBV group = 20, KVX group = 20); 191 observations were analysed. Male sex was associated with reduced leg fat mass, while age and body mass index (BMI) were associated with increased leg fat mass (all p < 0.05). Leg fat mass and male sex were associated with increased waist circumference (p < 0.001 for both). Leg fat mass predicted reduced ApoB/ApoA1 ratio, while age and BMI predicted increased ApoB/ApoA1 ratio (all p < 0.05). BMI predicted HOMA-IR increase (p = 0.0017). No differences in lipoatrophy, central fat accumulation, dyslipidaemia or glucose metabolism were observed among any of the three different nevirapine plus nucleoside backbone groups (TVD, CBV or KVX).

CONCLUSION

HAART including nevirapine has a limited impact on components of lipodystrophy in patients with HIV infection. Further studies are needed to verify if nevirapine overcomes the expected distinct lipodystrophy risk profile associated with different nucleoside backbone therapies.

Clinical experience with nevirapine combined with tenofovir plus emtricitabine or lamivudine-containing regimens in HIV-infected subjects

We retrospectively evaluated the durability and reasons for discontinuation of nevirapine (NVP) in combination with a tenofovir (TDF) and emtricitabine (FTC) or lamivudine (3TC)-containing antiretroviral therapy (ART) regimen in an Australian outpatient setting. Between January 2003 and June 2009, 64 patients (29 naïve and 35 treatment-experienced) received NVP/TDF-based regimens. The median exposure was 13.0 months (interquartile range [IQR] 6.0-20.0 months). The two- and three-year probability of continuing a NVP/TDF with FTC or 3TC regimen was 76% and 70%, respectively. Thirteen (20.3%) patients discontinued their regimen during the observation period. Reasons for discontinuation included virological failure in four (6.3%), rash in three (4.7%), lost to follow-up in three (4.7%), liver toxicity in two (3.1%) and HIV-1-related encephalopathy in one (1.6%). Long-term follow-up with a NVP/TDF-based regimen showed a low rate of discontinuation and enabled physicians to extend the use of ART over a long period, often with simplified (once-daily) regimens.

Nevirapine-associated hepatotoxicity was not predicted by CD4 count ≥250 cells/μL among women in Zambia, Thailand and Kenya

OBJECTIVE

The aim of the study was to determine risk factors for developing severe hepatotoxicity (grade 3 or 4 hepatotoxicity) and rash-associated hepatotoxicity (rash with ≥ grade 2 hepatotoxicity) among women initiating nevirapine-based antiretroviral therapy (ART).

METHODS

The Non-Nucleoside Reverse Transcriptase Inhibitor Response Study was a prospective cohort study carried out in Zambia, Thailand and Kenya. Between May 2005 and January 2007, we enrolled antiretroviral-naïve HIV-infected women initiating nevirapine-based ART. At enrollment and at weeks 2, 4, 8, 16 and 24, participants had serum alanine transferase (ALT) and aspartate transaminase (AST) measured and were evaluated clinically for hepatitis and rash.

RESULTS

Nevirapine-based ART was initiated in 820 women and baseline ALT or AST results were abnormal (≥ grade 1) in 113 (14%) women. After initiating nevirapine-based ART, severe hepatotoxicity occurred in 41 (5%) women and rash-associated hepatotoxicity occurred in 27 (3%) women. In a multivariate logistic regression model, severe hepatotoxicity and rash-associated hepatotoxicity were both associated with baseline abnormal (≥ grade 1) ALT or AST results, but not with a baseline CD4 cell count ≥250 cells/μL. Three participants (0.4%) died with symptoms suggestive of fatal hepatotoxicity; all three women had baseline CD4 count <100 cells/μL and were receiving anti-tuberculosis therapy.

CONCLUSION

Among women taking nevirapine-based ART, severe hepatotoxicity and rash-associated hepatotoxicity were predicted by abnormal baseline ALT or AST results, but not by a CD4 count ≥250 cells/μL. In resource-limited settings where transaminase testing is available, testing should focus on early time-points and on women with abnormal baseline ALT or AST results.

Premature onset of cardiovascular disease in HIV-infected individuals: the drugs and the virus

Life expectancy in HIV-infected individuals has been greatly enhanced through immunologic restoration and virologic suppression resulting from antiretroviral therapy. Current clinical HIV care in Western countries focuses on treatment of drug toxicities and prevention of comorbidities. These non-AIDS HIV-related comorbidities, such as cardiovascular disease, occur even in individuals with virologic suppression and manifest at an earlier age than when normally presenting in the general population. While traditional risk factors are present in many HIV-infected individuals who develop cardiovascular disease, the additional roles of HIV-related chronic inflammation and immune activation as well as chronic HIV viremia may be significant. This review provides current evidence for the contributions of the virus, in terms of both chronic viremia and its contribution via chronic low-level inflammation, immune activation, premature immune senescence and dyslipidemia, to the pathogenesis of HIV-related cardiovascular disease, and balances this against the propensity of specific antiretroviral therapies to cause cardiovascular disease, in particular through altered cholesterol metabolism.

Twelve-year experience of nevirapine use: benefits and convenience for long-term management in a French cohort of HIV-1-infected patients

OBJECTIVE

To describe safety and long-term efficacy of nevirapine (NVP) in a real-life setting.

RESULTS

From 1996 to 2008, among the 745 patients who received NVP, 592 were still followed in our center; of these, 231 had stopped NVP because of failure (42%), side effects (28%), other causes (30%). Twenty-seven percent of discontinuations occurred in the first 3 months; 68% were related to adverse events. In June 2008, 361/592 patients (61%) were still on NVP for a median duration of 176 weeks (range, 0.3-600), including 18% of naïve patients, 15% of patients who initiated NVP in the context of virologic failure, and 66% of patients with an undetectable viral load (switch strategy). Median CD4 cell count increased from 377/microL (range, 8-1449) to 549/microL (range, 144-1621). Viral load was below 200 copies/mL at the latest visit in 97%, 96%, and 100% of the patients in the naïve, failure, and switch groups, respectively. Over a 5-year period, the rate of antiretroviral drug persistence was 60.9% for NVP, 41.4% for efavirenz, and 23% for lopinavir/ritonavir (P < .0001).

CONCLUSIONS

In a real-life setting, NVP demonstrates sustained efficacy and good safety and is very convenient to use as reflected by a high rate of persistency.

Nevirapine hypersensitivity

Treatment of HIV-1 infections with nevirapine is associated with skin and liver toxicity. These two organ toxicities range from mild to severe, in rare cases resulting in life-threatening liver failure or toxic epidermal necrolysis. The study of the mechanistic steps leading to nevirapine-induced skin rash has been facilitated by the discovery of an animal model in which nevirapine causes a skin rash in rats that closely mimics the rash reported in patients. The similarity in characteristics of the rash between humans and rats strongly suggests that the basic mechanism is the same in both. The rash is clearly immune-mediated in rats, and partial depletion of CD4(+) T cells, but not CD8(+) T cells, is protective. We have demonstrated that the rash is related to the 12-hydroxylation of nevirapine rather than to the parent drug. This is presumably because the 12-hydroxy metabolite can be converted to a reactive quinone methide in skin, but that remains to be demonstrated. Although the rash is clearly related to the 12-hydroxy metabolite rather than the parent drug, cells from rechallenged animals respond ex vivo to the parent drug by producing cytokines such as interferon-gamma with little response to the 12-hydroxy metabolite, even when the rash was induced by treatment with the metabolite rather than the parent drug. This indicates that the response of T cells in vitro cannot be used to determine what caused an immune response. We are now studying the detailed steps by which the 12-hydroxy metabolite induces an immune response and skin rash. This animal model provides a unique tool to study the mechanistic details of an idiosyncratic drug reaction; however, it is likely that there are significant differences in the mechanisms of different idiosyncratic drug reactions, and therefore the results of these studies cannot safely be generalized to all idiosyncratic drug reactions.

An evidence-based review of treatment-related determinants of patients' nonadherence to HIV medications

Patients' adherence to antiretroviral medications is a primary determinant of both the effectiveness of treatment and the clinical course of HIV/AIDS. This empirical review is intended to compare the relative importance of patient and treatment characteristics on nonadherence behavior and the impact of nonadherence on treatment failure. Articles cited in PubMed and published between 2006 and June 2008 (n = 200) were reviewed to select those that address patient or treatment characteristics associated with nonadherence. Twenty-two articles were selected that provided odds ratio or hazard ratio statistics that quantified predictors of patients' level of nonadherence (e.g., <80%, 80%-95% and >95%). Results were summarized using random effects meta-analytic models. Predictors of nonadherence were divided into four predictive clusters (clinical predictors, comorbid predictors, treatment competence predictors, and dosing predictors). The summary odds ratios (ORs) of nonadherence for each cluster (in order of strength) were treatment competence 2.0 (95% confidence interval [CI]: 1.6-2.6), clinical predictors 1.6 (95% CI: 1.4-1.8), comorbid predictors 1.6 (95% CI: 1.4-1.8), and dosing predictors 1.5 (95% CI: 1.3-1.7). The effect of nonadherence on treatment failure supported the findings of two prior empirical reviews (OR 2.0, 95% CI: 1.6-2.5). Within dosing predictors, a pill burden of more versus less than 10 pills per day was associated with a much higher odds of nonadherence than twice versus once daily dosing or small differences in the number of types of antiretroviral treatments in a regimen. These results provide insight into the relative importance of various determinants of patient nonadherence that may inform the design of patient educational initiatives and initiatives to simplify treatment regimens.

Importance of promoting HIV testing for preventing secondary transmissions: modelling the Australian HIV epidemic among men who have sex with men

BACKGROUND

We address the research questions: (i) what proportion of new HIV infections is transmitted from people who are (a) undiagnosed, (b) in primary HIV infection (PHI), (c) on antiretroviral therapy?; and (ii) what is the expected epidemiological impact of (a) increasing the proportion of newly acquired HIV infections receiving early treatment, and (b) increasing HIV testing rates?

METHODS

We used a mathematical model to simulate HIV transmission in the population of men who have sex with men (MSM) in Australia. We calibrated the model using established biological and clinical data and a wide range of Australian MSM epidemiological and behavioural data sources.

RESULTS

We estimate that ~19% of all new HIV infections are transmitted from the ~3% of Australian HIV-infected MSM who are in PHI; ~31% of new HIV infections are estimated to be transmitted from the ~9% of MSM with undiagnosed HIV. We estimate that the average number of infections caused per HIV-infected MSM through the duration of PHI is ~0.14-0.28.

CONCLUSIONS

The epidemiological impact of increasing treatment in PHI would be modest due to insufficient detection of newly-infected individuals. In contrast, increases in HIV testing rates could have substantial epidemiological consequences. The benefit of testing will also increase over time. Promoting increases in the coverage and frequency of testing for HIV could be a highly-effective public health intervention, but the population-level impact of interventions based on promoting early treatment of patients diagnosed in PHI is likely to be small. Treating PHI requires further evaluation of its long-term effects on HIV-infected individuals.

Effects of nevirapine and efavirenz on HDL cholesterol levels and reverse cholesterol transport in mice

OBJECTIVE

The mechanism by which non-nucleoside reverse transcriptase inhibitors (NNRTIs) increase HDL cholesterol (HDL-C) in HIV+ patients and the benefits of this with respect to cardiovascular risk are not known. Studies were conducted to test the hypothesis that NNRTIs have a beneficial effect on HDL-C and reverse cholesterol transport (RCT).

METHODS

LDLr-/- and hA-I transgenic mice were fed a Western diet containing either nevirapine (20mg/kg per day), efavirenz (10mg/kg per day), or diet alone. hA-I transgenic mice underwent a study to measure RCT (measured by excretion of macrophage [(3)H]-cholesterol into HDL and feces) at 8 weeks.

RESULTS

LDLr-/- and hA-I transgenic mice treated with nevirapine and efavirenz had a significant increase in HDL-C level (up to 23% in hA-I transgenic) at 4 weeks. However, there was no difference in HDL levels beyond 4 weeks of treatment. At 4 weeks, the FPLC profile of hA-I transgenic mice showed an increase in large HDL. hApoA-I transgenic mice treated with efavirenz for 4 weeks had increased expression of human apoA-I in liver and an increased human apoA-I production rate. Incubation of plasma from hA-I transgenic mice treated for 4 weeks with [(3)H]-cholesterol-labeled macrophages revealed increased cholesterol efflux to plasma from mice treated with efavirenz and nevirapine. Following injection of hA-I transgenic mice treated for 8 weeks with [(3)H]-cholesterol-labeled macrophages, RCT was increased in the efavirenz (p=0.01) group and trended towards an increase in the nevirapine (p=0.15) group.

CONCLUSION

Nevirapine and efavirenz transiently increased HDL-C in LDLr-/- and hA-I transgenic mice fed a Western diet that was associated with increased apoA-I production. An increase in RCT in hA-I transgenic mice at 8 weeks despite no difference in HDL levels indicates that these drugs affect additional factors in the RCT pathway that enhance cholesterol efflux from the macrophage and peripheral tissues to plasma and delivery to liver for excretion. These results suggest that treatment with NNRTIs has a beneficial effect on cholesterol efflux and RCT.

Long-term follow-up of nevirapine-treated patients in a single-centre cohort

OBJECTIVES

We reviewed the safety and efficacy of nevirapine (NVP)-based therapy in all patients initiating NVP-containing combined antiretroviral therapy [cART (>or=3 drugs)] in our clinic since 1994.

METHODS

Patient characteristics and laboratory values from the start of the NVP-based cART regimen to the last available follow-up or to NVP discontinuation were retrieved from an observational database.

RESULTS

Five hundred and seventy-three patients were treated with NVP-based cART for a median of 18.4 (range 0.1-128.8) months. The 1-year cumulative estimated probability of discontinuing NVP-containing regimens for toxicity was 0.203. Only 1.9% developed a grade 3 alanine aminotransferase (ALT) elevation. Significant increases in high-density lipoprotein cholesterol were observed up to month 12 except in treatment-naïve patients, where the increase was limited to 3 months. Discontinuation because of cutaneous reaction was predicted independently by female gender [Hazard Ratio (HR) 3.21, P<0.001] and Centers for Disease Control class C (HR 0.50, P=0.012). Discontinuation because of liver toxicity was predicted independently by anti-hepatitis C virus positivity (HR 3.84, P<0.001). In patients starting NVP-containing cART with undetectable viral loads, the 5-year estimated probability of viral load >400 HIV-1 RNA copies/mL was 0.34.

CONCLUSIONS

Long-term follow-up with an NVP-containing cART showed a low rate of discontinuation caused by liver toxicity and the maintenance of virological suppression in patients switched with undetectable viral loads.

Liver enzymes improve over twenty-four months of first-line non-nucleoside reverse transcriptase inhibitor-based therapy in rural Uganda

We studied hepatic transaminases among rural Ugandans initiating highly active antiretroviral therapy (HAART) and assessed the impact of positive serology for hepatitis B surface antigen (HBsAg) and coadministration of therapy for tuberculosis. From July 2003 to December 2004, persons with symptomatic HIV disease or a CD4 count less than 250 cells/mm(3) and who had alanine transferase (ALT) or aspartate transferase (AST) less than 5 times the upper limit of normal were started on HAART including nevirapine (96%) or efavirenz (4%). Repository sera from a subset of 596 participants were analyzed for hepatic transaminase levels. A transaminase elevation was present before therapy for 249 (42%) of 596, at 3 months for 140 (25%) of 553, 12 months for 59 (11%) of 520, and 24 months for 67 (13%) of 508. In multivariate analyses, a transaminase elevation at 3 months was associated with male gender (odds ratio [OR], 1.55; 95% confidence interval [CI], 1.02-2.35), body mass index less than 18 kg/m(2) (OR, 2.10; 95% CI, 1.34-3.30), transaminase elevation at baseline (OR, 1.97; 95% CI, 1.30-2.99), and treatment for tuberculosis (OR, 4.68; 95% CI, 2.28-9.59). HBsAg status was not associated with transaminase elevations at baseline or while on HAART. The prevalence of hepatic transaminase elevations decreased during non-nucleoside reverse transcriptase inhibitor (NNRTI)-based antiretroviral therapy in this cohort of HIV-infected persons in rural Uganda.

Ethnicity, race, and gender. Differences in serious adverse events among participants in an antiretroviral initiation trial: results of CPCRA 058 (FIRST Study)

BACKGROUND

Differences in adverse events by gender and race/ethnicity have not been described extensively in randomized clinical trials of HIV antiretroviral therapy (ART).

METHODS

Antiretroviral-naive HIV-infected participants enrolled in a long-term randomized clinical trial of 3 different initial ART strategies -- protease inhibitor (PI), nonnucleoside reverse transcriptase inhibitor (NNRTI), or PI plus NNRTI-based combinations -- with a median follow-up of 5 years, were compared by gender and race for 14 categories of grade 4 adverse events, discontinuation of initial antiretroviral regimen, and all-cause mortality. Multivariate analysis was used to identify predictors of events and death.

RESULTS

Among 1301 participants with complete data, there were 701 blacks, 225 Latinos, and 263 women. Several baseline characteristics differed by gender and race, including age, HIV transmission risk, hepatitis B or C coinfection, viral load, diagnosis of AIDS, body mass index, and baseline hypertension. Grade 4 events occurred in 409 participants (rate: 8.9/100 person-years). There were 176 deaths (rate: 3.0/100 person-years) and 523 discontinuations of regimen for any toxicity (rate: 13/100 person-years). In the fully adjusted regressions, blacks had greater risk for cardiovascular (hazard ratio [HR] = 2.64, 95% confidence interval [CI]: 1.04 to 6.67) and renal (HR = 3.83, 95% CI: 1.28 to 11.5) events. Black men had more psychiatric events (HR = 2.45, 95% CI: 1.13 to 5.30). Women had a higher risk for anemia (HR = 2.34, 95% CI: 1.09 to 4.99).

CONCLUSION

Among HIV-infected participants initiating ART, there were significant risk-adjusted differences for specific adverse events by gender and race but not in the overall adverse event rates, all-cause mortality, or rates of toxicity-related treatment discontinuations.

Analysis of severe hepatic events associated with nevirapine-containing regimens: CD4+ T-cell count and gender in hepatitis C seropositive and seronegative patients

BACKGROUND

Nevirapine-containing regimens have been associated with a risk of significant elevations of liver transaminase levels. Higher risk in antiretroviral-naive populations has been related to gender and CD4+ T-cell count (women with CD4+ T-cell counts of > or =250/mm(3) or men with CD4+ T-cell counts of > or =400/mm(3), i.e. group at risk). However, recent studies do not confirm this association in HIV populations comprising patients who are antiretroviral-experienced. Moreover, the predictive value of gender and CD4+ T-cell count on the risk of raised transaminase levels has been poorly investigated in populations of patients co-infected with hepatitis C virus (HCV).

METHODS

Analysis of HIV-positive patients receiving nevirapine-containing regimens for the first time was conducted. Grade > or =III hepatotoxicity (i.e. > or =5 x upper limit of normal in alanine aminotranferase or aspartate aminotransferase levels) was the primary endpoint. Univariate and multivariable Cox proportional hazard regression models were separately conducted among HCV-antibody (Ab)-positive and HCV-Ab-negative patients.

RESULTS

Amongst 905 patients, 49% were HCV-Ab-positive and 79% were antiretroviral-experienced. Grade > or =III liver transaminase elevations developed in 7.1% of patients, accounting for an incidence of 2.47 (95% CI 1.97, 3.09) per 100 patient-years of follow-up. HCV-Ab reactivity was associated with a 3-fold increase in risk of developing relevant liver transaminase elevations (95% CI 1.75, 5.3; p < 0.001), whereas gender and CD4+ T-cell count did not impact significantly. When analysis was performed in HCV-Ab-negative patients, the outcome was independently correlated with the group at risk (hazard ratio [HR] 3.66; 95% CI 1.20, 11.14; p = 0.022). By contrast, in HCV-Ab-positive patients, the group at risk was not significantly associated with the outcome.

CONCLUSIONS

Most of the excess rates of relevant raised transaminase levels in patients prescribed nevirapine-containing regimens could be attributed to HCV co-infection. Gender and CD4+ T-cell count appeared to have a statistically significant impact on the risk of relevant transaminase level elevations in HCV-negative, but not in HCV-positive patients, probably due to a diluting effect of HCV. Incidence of hepatic events after nevirapine-containing regimens did not appear to be a major concern in our cohort of patients who were mainly antiretroviral-experienced and negative for HCV-Ab. Preferably, nevirapine should be avoided in HCV co-infected patients and in males with CD4+ T-cell counts of > or =400/mm(3) or females with CD4+ T-cell counts of > or =250/mm(3).

Pharmacokinetics of lamivudine, zidovudine, and nevirapine administered as a fixed-dose combination formulation versus coadministration of the individual products

The pharmacokinetics of 150 mg lamivudine, 300 mg zidovudine, and 200 mg nevirapine were assessed following single oral administration of a fixed-dose combination tablet and coadministration of the separate innovator products in healthy male subjects (n = 64) under fasting conditions in an open-label, randomized, 2-way crossover study. Multiple blood samples were collected up to 72 hours and plasma concentrations of antiretrovirals were assayed using liquid chromatography/tandem mass spectrometry methods. Pharmacokinetic parameters were calculated using noncompartmental methods, and bioequivalence was assessed using an analysis of variance model. The ratio of the least squares mean (fixed-dose combination to individual products) and 90% confidence intervals of AUC(0-t), AUC(0-infinity), and C(max) for lamivudine, zidovudine, and nevirapine were all within 80.0% to 125.0%, suggesting a similar rate and extent of antiretroviral exposure in the bloodstream. Mean oral clearance (CL/F) values of lamivudine, zidovudine, and nevirapine for the fixed-dose combination were 23.7, 127, and 1.65 L/h, respectively. The fixed-dose combination and individual products were equally safe and well tolerated, with only a few subjects experiencing drug-related adverse events. The current fixed-dose combination of lamivudine, zidovudine, and nevirapine is expected to provide a similar efficacy/safety profile as coadministration of the individual products, a better adherence to treatment, and considerable cost savings in the treatment of HIV.

Using mathematical modelling to help explain the differential increase in HIV incidence in New South Wales, Victoria and Queensland: importance of other sexually transmissible infections

Background: Since 1999 there has been an increase in the number of HIV diagnoses in Australia, predominantly among men who have sex with men (MSM), but the magnitude of increase differs between states: ~7% rise in New South Wales, ~96% rise in Victoria, and ~68% rise in Queensland. Methods: Epidemiological, clinical, behavioural and biological data were collated into a mechanistic mathematical model to explore possible reasons for this increase in HIV notifications in MSM. The model was then used to make projections to 2015 under various scenarios. Results: The model suggests that trends in clinical and behavioural parameters, including increases in unprotected anal intercourse, cannot explain the magnitude of the observed rise in HIV notifications, without a substantial increase in a ‘transmission-increasing’ factor. We suggest that a highly plausible biological factor is an increase in the prevalence of other sexually transmissible infections (STI). It was found that New South Wales required an ~2-fold increase in other STI to match the data, Victoria needed an ~11-fold increase, and Queensland required an ~9-fold increase. This is consistent with observed trends in Australia for some STI in recent years. Future projections also indicate that the best way to control the current rise in HIV notifications is to reduce the prevalence of other STI and to promote condom use, testing for HIV, and initiation of early treatment in MSM diagnosed during primary infection. Conclusions: Our model can explain the recent rise in HIV notifications with an increase in the prevalence of other STI. This analysis highlights that further investigation into the causes and impact of other STI is warranted in Australia, particularly in Victoria.

Nevirapine versus efavirenz in 742 patients: no link of liver toxicity with female sex, and a baseline CD4 cell count greater than 250 cells/microl

Recent studies have reported increased nevirapine hepatotoxicity in female patients with CD4 lymphocyte counts greater than 250 cells/microl (especially pregnant women). However, our open-label comparison of 742 patients treated with either nevirapine or efavirenz-based HAART as naive patients, experienced subjects, or patients on salvage therapy, found no increased hepatotoxicity in nevirapine-treated subjects, in particular with regard to both sex (females versus males) and T-cell-mediated immunodeficiency (CD4 cell counts above versus below 250 cells/microl).