Serious Adverse Cutaneous and Hepatic Toxicities Associated With Nevirapine Use by Non???HIV-Infected Individuals

The role of corticosterone in nevirapine-induced idiosyncratic drug-induced liver injury

Nevirapine, an antiretroviral used in the treatment of HIV, is associated with idiosyncratic drug-induced liver injury (IDILI), a potentially life-threatening adverse drug reaction. Its usage has decreased due to this concern, but it is still widely used in lower-resource settings. In general, the mechanisms underlying idiosyncratic drug reactions (IDRs) are poorly understood, but evidence indicates that most are immune-mediated. There is very limited understanding of the early immune response following administration of drugs associated with IDRs, which likely occurs due to reactive metabolite formation. In this work, we aimed to characterize the links between covalent binding of nevirapine, the development of an early immune response, and the subsequent liver injury using a mouse model. We describe initial attempts to characterize an early immune response to nevirapine followed by the discovery that nevirapine induced the release of corticosterone. Corticosterone release was partially associated with the degree of drug covalent binding in the liver but was also likely mediated by additional mechanisms at higher drug doses. Transcriptomic analysis confirmed metabolic activation, glucocorticoid signaling, and decreased immune activation; GDF-15 also warrants further investigation as part of the immune response to nevirapine. Finally, glucocorticoid blockade preceding the first dose of nevirapine attenuated nevirapine-induced liver injury at 3 weeks, suggesting that acute glucocorticoid signaling is harmful in the context of nevirapine-induced liver injury. This work demonstrates that nevirapine induces acute corticosterone release, which contributes to delayed-onset liver injury. It also has implications for screening drug candidates for IDILI risk and preventing nevirapine-induced IDILI.

NNRTI and Liver Damage: Evidence of Their Association and the Mechanisms Involved

Due to the improved effectiveness and safety of combined antiretroviral therapy, human immunodeficiency virus (HIV) infection has become a manageable, chronic condition rather than a mortal disease. However, HIV patients are at increased risk of experiencing non-AIDS-defining illnesses, with liver-related injury standing out as one of the leading causes of death among these patients. In addition to more HIV-specific processes, such as antiretroviral drug-related toxicity and direct injury to the liver by the virus itself, its pathogenesis is related to conditions that are also common in the general population, such as alcoholic and non-alcoholic fatty liver disease, viral hepatitis, and ageing. Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are essential components of combined anti-HIV treatment due to their unique antiviral activity, high specificity, and acceptable toxicity. While first-generation NNRTIs (nevirapine and efavirenz) have been related largely to liver toxicity, those belonging to the second generation (etravirine, rilpivirine and doravirine) seem to be generally safe for the liver. Indeed, there is preclinical evidence of rilpivirine being hepatoprotective in different models of liver injury, independently of the presence of HIV. The present study aims to review the mechanisms by which currently available anti-HIV drugs belonging to the NNRTI family may participate in the development of liver disease.

Clinical and genetic factors associated with increased risk of severe liver toxicity in a monocentric cohort of HIV positive patients receiving nevirapine-based antiretroviral therapy

Background

Nevirapine has been used as antiretroviral agent since early ‘90. Although nevirapine is not currently recommended in initial anti-HIV regimens, its use remains consistent in a certain number of HIV-1-positive subjects. Thus, our aim was to determine clinical and genetic factors involved in the development of severe nevirapine induced liver toxicity.

Methods

We retrospectively analyzed all HIV positive patients who were followed at the Infectious Diseases Unit, DIBIC Luigi Sacco, University of Milan from May 2011 to December 2015. All patients treated with nevirapine who underwent a genotyping for the functional variants mapping into ABCB1, CYP2B6, CYP3A4 and CYP3A5 genes were included in the analysis. Severe hepatotoxicity was defined as ACTG grade 3–4 AST/ALT increase during the first three months of nevirapine treatment. The causality assessment between NVP exposure and drug-induced liver injury was performed by using the updated Roussel Uclaf Causality Assessment Methods. Hardy Weinberg equilibrium was tested by χ² test. A multivariable logistic regression model was constructed using a backward elimination method.

Results

Three hundred and sixty-two patients were included in the analysis, of which 8 (2.2%) experienced a severe liver toxicity. We observed no differences between patients with and without liver toxicity as regards gender, ethnicity, age and immune-virological status. A higher prevalence of HCV coinfection (75.0% vs 30.2%; p = .0013) and higher baseline AST (58 IU/L vs 26 IU/L; p = 0.041) and ALT (82 IU/L vs 27 IU/L; p = 0.047) median levels were observed in patients with liver toxicity vs those without toxicity. The genotypes CT/TT at ABCB1 rs1045642 single nucleotide polymorphism (SNP), showed a protective effect for liver toxicity when compared with genotype CC (OR = 0.18, 95%CI 0.04–0.76; p = 0.020) in univariate analysis. In the multivariate model, HCV coinfection was independently associated with higher risk of developing liver toxicity (aOR = 8.00, 95%CI 1.27–50.29; p = 0.027), whereas ABCB1 rs1045642 CT/TT genotypes (aOR = 0.10, 95%CI 0.02–0.47; p = 0.004) was associated with a lower risk.

Conclusions

According to our findings HCV coinfection and ABCB1 rs1045642 SNP represent independent determinants of severe liver toxicity related to nevirapine. This genetic evaluation could be included as toxicity assessment in HIV-1-positive subjects treated with nevirapine.

Post-exposure prophylaxis following occupational exposure to HIV and hepatitis B: an analysis of a 12-year record in a Nigerian tertiary hospital

BACKGROUND

Healthcare workers (HCWs) have an increased risk of occupational exposure to blood-borne pathogens.

AIMS/OBJECTIVES

We aim to examine the utilisation and outcome of post-exposure prophylaxis (PEP) for both HIV and hepatitis B (HBV) among HCWs.

METHODS

This was a retrospective study conducted in a tertiary hospital in North-Western Nigeria. We reviewed data on HIV or HBV PEP given to HCWs between 2004 and 2016.

RESULTS

A total of 115 HCWs presented for PEP during the study period. Intern doctors were the most exposed group (40/115; 34.8%). There were 86/115 (74.8%) needle stick exposures. While 53/115 (46.1%) of the sources of exposure were HIV-positive, 9/115(7.83%) were HBV-positive. Zidovudine-based regimen (40/70) was the most commonly prescribed. No seroconversion occurred among those that completed PEP treatment and follow-up.

DISCUSSION

No seroconversion occurred among those that received either or both HIV and HBV PEP and completed PEP treatment.

Building predictive in vitro pulmonary toxicity assays using high-throughput imaging and artificial intelligence

Human lungs are susceptible to the toxicity induced by soluble xenobiotics. However, the direct cellular effects of many pulmonotoxic chemicals are not always clear, and thus, a general in vitro assay for testing pulmonotoxicity applicable to a wide variety of chemicals is not currently available. Here, we report a study that uses high-throughput imaging and artificial intelligence to build an in vitro pulmonotoxicity assay by automatically comparing and selecting human lung-cell lines and their associated quantitative phenotypic features most predictive of in vivo pulmonotoxicity. This approach is called “High-throughput In vitro Phenotypic Profiling for Toxicity Prediction” (HIPPTox). We found that the resulting assay based on two phenotypic features of a human bronchial epithelial cell line, BEAS-2B, can accurately classify 33 reference chemicals with human pulmonotoxicity information (88.8% balance accuracy, 84.6% sensitivity, and 93.0% specificity). In comparison, the predictivity of a standard cell-viability assay on the same set of chemicals is much lower (77.1% balanced accuracy, 84.6% sensitivity, and 69.5% specificity). We also used the assay to evaluate 17 additional test chemicals with unknown/unclear human pulmonotoxicity, and experimentally confirmed that many of the pulmonotoxic reference and predicted-positive test chemicals induce DNA strand breaks and/or activation of the DNA-damage response (DDR) pathway. Therefore, HIPPTox helps us to uncover these common modes-of-action of pulmonotoxic chemicals. HIPPTox may also be applied to other cell types or models, and accelerate the development of predictive in vitro assays for other cell-type- or organ-specific toxicities.

Dolutegravir with tenofovir disoproxil fumarate-emtricitabine as HIV postexposure prophylaxis in gay and bisexual men

OBJECTIVES

Completion rates for HIV postexposure prophylaxis (PEP) are often low. We investigated the adherence and safety of dolutegravir (DTG; 50 mg daily) with tenofovir disoproxil fumarate-emtricitabine (TDF-FTC; 300/200 mg, respectively) as three-drug PEP in gay and bisexual men.

DESIGN

Open-label, single-arm study at three sexual health clinics and two emergency departments in Australia.

METHODS

In total, 100 HIV-uninfected gay and bisexual men requiring PEP received DTG and TDF-FTC for 28 days. The primary end point was PEP failure (premature PEP cessation or primary HIV infection through week 12). Additional end points were adherence by self-report (n = 98) and pill count (n = 55), safety, and plasma drug levels at day 28.

RESULTS

PEP completion was 90% (95% confidence interval 84-96%). Failures (occurring at a median 9 days, interquartile range 3-16) comprised loss to follow-up (9%) and adverse event resulting in study drug discontinuation (headache, 1%). No participant was found to acquire HIV through week 12. Adherence to PEP was 98% by self-report and in the 55 participants with corresponding pill count data. The most common clinical adverse events were fatigue (26%), nausea (25%), diarrhoea (21%), and headache (10%). There were only four grade 3-4 subjective adverse events. The most common laboratory adverse event was raised alanine aminotransferase (22%), but there was no case of clinical hepatitis. At day 28, the mean estimated glomerular filtration rate decrease was 14 ml/min/1.73m (SD 17, P = 0.001); an estimated glomerular filtration rate of less than 60 ml/min/1.73m occurred in 3%.

CONCLUSIONS

DTG with TDF-FTC is a well tolerated option for once-daily PEP.

Mechanisms of Drug-Induced Hepatotoxicity

Drug-induced hepatotoxicity (DIH) is a significant cause of acute liver failure and liver transplantation. Diagnosis is challenging due to the idiosyncratic nature, its presentation in the form of other liver disease, and the lack of a definite diagnostic criteria. Generation of reactive metabolites, oxidative stress, and mitochondrial dysfunction are common mechanisms involved in DIH. Certain risk factors associated with a drug and within an individual further predispose patients to DIH.

UK guideline for the use of HIV Post-Exposure Prophylaxis Following Sexual Exposure, 2015

We present the updated British Association for Sexual Health and HIV guidelines for HIV post-exposure prophylaxis following sexual exposure (PEPSE). This document includes a review of the current data to support the use of PEPSE, considers how to calculate the risks of infection after a potential exposure, and provides recommendations on when PEPSE should and should not be considered. We also review which medications to use for PEPSE, provide a checklist for initial assessment, and make recommendations for monitoring individuals receiving PEPSE. Special scenarios, cost-effectiveness of PEPSE, and issues relating to service provision are also discussed. Throughout the document, the place of PEPSE within the broader context of other HIV prevention strategies is considered.

Prospective, Open-Label Comparative Study of Liver Toxicity in an Unselected Population of HIV-Infected Patients Treated for the First Time with Efavirenz or Nevirapine

OBJECTIVE

To compare the two nonnucleoside reverse transcriptase inhibitors (NNRTIs) when first introduced in an antiretroviral regimen, a prospective open-label assessment of the frequency, severity, risk factors, and outcome of hepatotoxicity was performed.

METHOD

Liver enzymes were followed-up during 18 months in patients who received efavirenz (EFV; 324 patients) or nevirapine (NVP; 299).

RESULTS

The two study groups were comparable, except for the lower baseline CD4+ count found in the EFV group. No differences were found when considering the type and duration of eventual prior anti-HIV therapy; frequency and length of protease inhibitors, methadone, or anti-tubercular drug use; HCV-HBV co-infection; other hepatobiliary disorders; and alcohol-drug abuse. The frequency of overall and first-month drug interruption proved similar in the two study groups. A hepatotoxicity characterized by at least a 2-fold increase of transaminases versus baseline was significantly linked with NVP, and the number of patients showing hepatotoxicity tended to a reduction in the EFV group. Also the time to peak transaminase alterations was shorter in the NVP group. All significant differences regarding liver-pancreatic toxicities were controlled per eventual baseline hepatobiliary-pancreatic diseases, HIV stage, and concurrent drug therapies.

DISCUSSION

Hepatotoxicity is a significant concern in the setting of antiretroviral-treated HIV disease. NVP-based HAART may be more hepatotoxic than EFV-based HAART, and a role is played by chronic liver disorders. Although concurrent hepatobiliary disorders and the possible hepatotoxicity of antiretrovirals do not represent contraindications to nonnucleoside inhibitor use, strict monitoring is recommended.

Fatigue Increases the Risk of Injury From Sharp Devices in Medical Trainees Results From a Case-Crossover Study

Background.

Extreme fatigue in medical trainees likely compromises patient safety, but regulations that limit trainee work hours have been controversial. It is not known whether extreme fatigue compromises trainee safety in the healthcare workplace, but evidence of such a relationship would inform the current debate on trainee work practices. Our objective was to evaluate the relationship between fatigue and workplace injury risk among medical trainees and nontrainee healthcare workers.

Design.

Case-crossover study.

Setting.

Five academic medical centers in the United States and Canada.

Participants.

Healthcare workers reporting to employee healthcare clinics for evaluation of needlestick injuries and other injuries related to sharp instruments and devices (sharps injuries). Consenting workers completed a structured interview about work patterns, time at risk of injury, and frequency of fatigue.

Results.

Of 350 interviewed subjects, 109 (31%) were medical trainees. Trainees worked more hours per week (P < .001) and slept less the night before an injury (P < .001) than did other healthcare workers. Fatigue increased injury risk in the study population as a whole (incidence rate ratio [IRR], 1.40 [95% confidence interval {CI}, 1.03-1.90]), but this effect was limited to medical trainees (IRR, 2.94 [95% CI, 1.71-5.07]) and was absent for other healthcare workers (IRR, 0.97 [95% CI, 0.66-1.42]) (P = .001).

Conclusions.

Long work hours and sleep deprivation among medical trainees result in fatigue, which is associated with a 3-fold increase in the risk of sharps injury. Efforts to reduce trainee work hours may result in reduced risk of sharps-related injuries among this group.

Prevention of human immunodeficiency virus and AIDS: postexposure prophylaxis (including health care workers)

Postexposure prophylaxis (PEP), which is designed to prevent human immunodeficiency virus (HIV) infection after an exposure, is one of several strategies for HIV prevention. PEP was first used after occupational HIV exposures in the late 1980s, with the Centers for Disease Control and Prevention issuing the first set of guidelines that included considerations regarding the use of antiretroviral agents for PEP after occupational HIV exposures in 1990. Use of PEP has been extended to nonoccupational exposures, including after sexual contact or injection-drug use. This article provides a rationale for PEP, assessment of the need for PEP, and details of its implementation.

Results from the first decade of research conducted by the Research on Adverse Drug Events and Reports (RADAR) project

INTRODUCTION

In 1998, a multidisciplinary team of investigators initiated the Research on Adverse Drug events And Reports (RADAR) project, a post-marketing surveillance effort that systematically investigates and disseminates information describing serious and previously unrecognized serious adverse drug and device reactions (sADRs).

OBJECTIVE

Herein, we describe the findings, dissemination efforts, and lessons learned from the first decade of the RADAR project.

METHODS

After identifying serious and unexpected clinical events suitable for further investigation, RADAR collaborators derived case information from physician queries, published and unpublished clinical trials, case reports, US FDA databases and manufacturer sales figures.

STUDY SELECTION

All major RADAR publications from 1998 to the present are included in this analysis.

DATA EXTRACTION

For each RADAR publication, data were abstracted on data source, correlative basic science findings, dissemination and resultant safety information.

RESULTS

RADAR investigators reported 43 serious ADRs. Data sources included case reports (17 sADRs), registries (5 sADRs), referral centers (8 sADRs) and clinical trial reports (13 sADRs). Correlative basic science findings were reported for ten sADRs. Thirty-seven sADRS were described as published case reports (5 sADRs) or published case-series (32 sADRs). Related safety information was disseminated as warnings or boxed warnings in the package insert (17 sADRs) and/or 'Dear Healthcare Professional' letters (14 sADRs).

CONCLUSION

An independent National Institutes of Health-funded post-marketing surveillance programme can supplement existing regulatory and pharmaceutical manufacturer-supported drug safety initiatives.

Quinone Methide Bioactivation Pathway: Contribution to Toxicity and/or Cytoprotection?

The formation of quinone methides (QMs) from either direct 2-electron oxidation of 2- or 4-alkylphenols, isomerization of o-quinones, or elimination of a good leaving group could explain the cytotoxic/cytoprotective effects of several drugs, natural products, as well as endogenous compounds. For example, the antiretroviral drug nevirapine and the antidiabetic agent troglitazone both induce idiosyncratic hepatotoxicity through mechanisms involving quinone methide formation. The anesthetic phencyclidine induces psychological side effects potentially through quinone methide mediated covalent modification of crucial macromolecules in the brain. Selective estrogen receptor modulators (SERMs) such as tamoxifen, toremifene, and raloxifene are metabolized to quinone methides which could potentially contribute to endometrial carcinogenic properties and/or induce detoxification enzymes and enhance the chemopreventive effects of these SERMs. Endogenous estrogens and/or estrogens present in estrogen replacement formulations are also metabolized to catechols and further oxidized to o-quinones which can isomerize to quinone methides. Both estrogen quinoids could cause DNA damage which could enhance hormone dependent cancer risk. Natural products such as the food and flavor agent eugenol can be directly oxidized to a quinone methide which may explain the toxic effects of this natural compound. Oral toxicities associated with chewing areca quid could be the result of exposure to hydroxychavicol through initial oxidation to an o-quinone which isomerizes to a p-quinone methide. Similar o-quinone to p-quinone methide isomerization reactions have been reported for the ubiquitous flavonoid quercetin which needs to be taken into consideration when evaluating risk-benefit assessments of these natural products. The resulting reaction of these quinone methides with proteins, DNA, and/or resulting modulation of gene expression may explain the toxic and/or beneficial effects of the parent compounds.

What primary care providers need to know about preexposure prophylaxis for HIV prevention: a narrative review

As HIV prevalence climbs globally, including more than 50 000 new infections per year in the United States, we need more effective HIV prevention strategies. The use of antiretrovirals for preexposure prophylaxis (PrEP) among high-risk persons without HIV is emerging as one such strategy. Randomized, controlled trials have demonstrated that once-daily oral PrEP decreased HIV incidence among at-risk men who have sex with men and African heterosexuals, including serodiscordant couples. An additional randomized, controlled trial of a topical pericoital antiretroviral microbicide gel decreased HIV incidence among at-risk heterosexual South African women. Two other studies in African women did not demonstrate the efficacy of oral or topical PrEP, raising concerns about adherence patterns and efficacy in this population. The U.S. Food and Drug Administration (FDA) Antiviral Drugs Advisory Committee reviewed these studies and additional data in May 2012 and voted to advise the approval of oral tenofovir-emtricitabine for PrEP in high-risk populations. On 16 July 2012, the FDA recommended that this combination medication be approved for use as PrEP in high-risk persons without HIV. Patients may seek PrEP from their primary care providers, and those receiving PrEP require monitoring. Thus, primary care providers should become familiar with PrEP. This review outlines current knowledge about PrEP as it pertains to primary care, including identifying persons likely to benefit from PrEP; counseling to maximize adherence and reduce potential increases in risky behavior; and monitoring for potential drug toxicities, HIV acquisition, and antiretroviral drug resistance. Issues related to cost and insurance coverage are also discussed. Recent data suggest that PrEP, combined with other prevention strategies, holds promise in helping to curtail the HIV epidemic.

The pharmacogenetics of antiretroviral therapy

PURPOSE OF REVIEW

Although the past 20 years have seen many advances in HIV pharmacotherapy, host variability has only been more recently recognized as an important driver of both treatment response and toxicity. This review will focus on the importance of variability in drug metabolizing enzymes and the potential research and clinical applications of these findings in HIV care.

RECENT FINDINGS

The treatment of HIV is complex and involves chronic treatment with multiple drugs and drug classes. Recent research has been important in uncovering genetic differences in drug metabolizing and drug transporter genes, which underpin dose-dependent toxicity and efficacy, but also in genes defining differences in immune response and human leukocyte antigen genes, which restrict processes that are less dependent on the drug dose.

SUMMARY

The advancement of pharmacogenetics will continue to further our knowledge of disease-drug interactions and pathogenesis. Ultimately, the goals of pharmacogenetics and pharmacogenomics in HIV medicine will be the development of the right drugs for the right patient or population. The strong association between HLA-B5701 and abacavir hypersensitivity reaction shows promise for a genetic screening test to be feasibly incorporated into clinical practice. The clinical applicability of many findings demonstrating associations between single nucleotide polymorphisms, particularly in drug metabolism and transporter genes and drug efficacy and toxicity, are currently uncertain.

Bioactivation of nevirapine to a reactive quinone methide: implications for liver injury

Nevirapine (NVP) treatment is associated with a significant incidence of liver injury. We developed an anti-NVP antiserum to determine the presence and pattern of covalent binding of NVP to mouse, rat, and human hepatic tissues. Covalent binding to hepatic microsomes from male C57BL/6 mice and male Brown Norway rats was detected on Western blots; the major protein had a mass of ~55 kDa. Incubation of NVP with rat CYP3A1 and 2C11 or human CYP3A4 also led to covalent binding. Treatment of female Brown Norway rats or C57BL/6 mice with NVP led to extensive covalent binding to a wide range of proteins. Co-treatment with 1-aminobenzotriazole dramatically changed the pattern of binding. The covalent binding of 12-hydroxy-NVP, the pathway that leads to a skin rash, was much less than that of NVP, both in vitro and in vivo. An analogue of NVP in which the methyl hydrogens were replaced by deuterium also produced less covalent binding than NVP. These data provide strong evidence that covalent binding of NVP in the liver is due to a quinone methide formed by oxidation of the methyl group. Attempts were made to develop an animal model of NVP-induced liver injury in mice. There was a small increase in ALT in some NVP-treated male C57BL/6 mice at 3 weeks that resolved despite continued treatment. Male Cbl-b(-/-) mice dosed with NVP had an increase in ALT of >200 U/L, which also resolved despite continued treatment. Liver histology in these animals showed focal areas of complete necrosis, while most of the liver appeared normal. This is a different pattern from the histology of NVP-induced liver injury in humans. This is the first study to report hepatic covalent binding of NVP and also liver injury in mice. It is likely that the quinone methide metabolite is responsible for NVP-induced liver injury.

The role of the immune system in nevirapine-induced subclinical liver injury of a rat model

In this study, the role of the immune system in nevirapine- (NVP-) induced subclinical liver injury was investigated by observing for changes of some immune parameters during the initial stages of NVP-induced hepatotoxicity in a rat model. In the acute phase, two test-groups of 10 Sprague-Dawley rats each were administered with bacterial lipopolysaccharide (LPS) or saline (S) intraperitoneally, followed by oral NVP, after which 5 rats from each group were sacrificed at 6 and 24 hours. For the chronic phase, two groups of 15 rats each received daily NVP, and on days 7, 14, and 21, five rats from each group were administered with either LPS or S, followed by that day's NVP dose, and were sacrificed 24 hours later. NVP caused liver injury up to seven days and progressively increased IL-2 and IFN-γ levels and lymphocyte count over the 21 days. NVP-induced liver injury was characterized by apoptosis and degeneration changes, while, for LPS, it was cell swelling, leukostasis, and portal inflammation. Coadministration of NVP and LPS attenuated NVP-induced liver injury. In conclusion, the immune system is involved in NVP toxicity, and the LPS effects may lay the clue to development of therapeutic strategies against NVP-induced hepatotoxicity.

HLA-dependent hypersensitivity reaction to nevirapine in Chinese Han HIV-infected patients

In this study, one hundred and three HIV-positive Chinese Han patients treated with a nevirapine (NVP)-based regimens were investigated for the association between nevirapine hypersensitivity reaction (NVP HSR) and human leukocyte antigen (HLA) allele. HLA-Cw, -DRB1 alleles were determined in 32 NVP HSR cases and 71 NVP-tolerant patients. We found that considerable overlap was observed for the clinical and demographic characteristics of the 32 hypersensitive patients and 71 tolerant patients. Twelve out of 32 NVP HSR cases developed allergic hepatotoxicity. More HLA-Cw*04 alleles were observed in NVP HSR cases than in NVP-tolerant cases (p=0.029). The frequency of HLA-DRB1*15 in NVP-tolerant cases was significant higher than that in NVP HSR cases ( p=0.018). Multivariate logistic regression identified that HLA-Cw*04 presence was a risk factor related to NVP HSR (p=0.030, OR=3.611, 95% CI of OR: 1.135-11.489). To clearly understanding its value in clinical practice, further studies involving larger cohorts of patients from different races with different levels of immune suppression are needed.

Raltegravir, tenofovir DF, and emtricitabine for postexposure prophylaxis to prevent the sexual transmission of HIV: safety, tolerability, and adherence

Antiretroviral drugs have been recommended for postexposure prophylaxis (PEP) after high-risk sexual exposures for more than a decade. Three drug regimens could offer the highest levels of protection, particularly if the infectious source is taking medication, but drug intolerance has often led to suboptimal adherence. The current study evaluated a novel 3-drug PEP regimen, consisting of raltegravir, tenofovir DF, and emtricitabine. Of 100 participants enrolled in this study at a Boston community health center that has had a comprehensive PEP program for more than a decade, 85 were evaluable at 3 months and none became HIV infected. Fifty seven percent of those enrolled completed the regimen as prescribed, and 27% took their medicine daily, but sometimes missed the second daily dose of Raltegravir. The most common side effects reported included nausea or vomiting (27%), diarrhea (21%), headache (15%), fatigue (14%), abdominal symptoms (including pain, gas, or bloating) (16%), and myalgias or arthralgias (8%), all of which were mild and tended to be self-limited, not resulting in drug discontinuation. The side effects were significantly less common than those reported by historical controls, who used a 3-drug PEP regimen including zidovudine, lamivudine, and a ritonavir-boosted protease inhibitor. Raltegravir, tenofovir DF, and emtricitabine may be useful as a 3-drug regimen for PEP.

The use of preexposure treatments for HIV prophylaxis

Infection with human immunodeficiency virus remains a global concern with a significant number of incident infections still reported worldwide. The use of prophylaxis prior to exposure to the virus to prevent infection has been a growing area of recent research. Results in nonhuman primates and clinical trials in high-risk patient populations using preexposure prophylaxis have shown promising results in terms of efficacy and safety, especially relating to oral preexposure prophylaxis. The potential use of oral antiretroviral agents traditionally used for human immunodeficiency virus treatment as prophylaxis raises interesting considerations, such as the best agents available for such a role, long-term safety in healthy individuals, and the potential development of resistance to these agents should infection occur. From a public health perspective, the cost-effectiveness of implementing this preventive strategy has not been fully defined at this point in time.

Promising prevention approaches: tenofovir gel and prophylactic use of antiretroviral medications

Thirty years into the global HIV epidemic, the need for effective prevention strategies remains critical. In July 2010, the CAPRISA-004 study demonstrated that topical administration of a gel containing the antiretroviral agent tenofovir decreased the risk of HIV acquisition among at-risk heterosexual women. Subsequently, the iPrEx study reported that prophylactic use of a daily oral tablet containing tenofovir and emtricitabine reduced the risk of HIV acquisition among high-risk men who have sex with men. These studies illustrate the promise of antiretroviral pre-exposure chemoprophylaxis (PrEP) as an innovative prevention approach. This review discusses the rationale for chemoprophylaxis, compares the advantages of topical and oral delivery, outlines recommended safety monitoring, offers principles to guide selection of antiretroviral agents, and highlights potential unintended consequences of PrEP use. If future studies confirm the safety and efficacy of tenofovir gel and oral PrEP, successful implementation of these strategies could significantly impact the HIV epidemic.

Fatal toxicity from symptomatic hyperlactataemia: a retrospective cohort study of factors implicated with long-term nucleoside reverse transcriptase inhibitor use in a South African hospital

BACKGROUND

In many Sub-Saharan African countries, first-line therapy for HIV may include a nucleoside reverse transcriptase inhibitor (NRTI). Long-term NRTI use is associated with symptomatic hyperlactataemia due to inhibition of mitochondrial DNA polymerase γ, a potentially fatal complication.

OBJECTIVE

The purpose of the study was to evaluate the factors associated with inhospital fatality for HIV inpatients prescribed NRTIs long term who presented with symptomatic hyperlactataemia.

METHODS

We performed a retrospective cohort study at a 900-bed university hospital in South Africa over 4 years (2005-2008). We included HIV inpatients prescribed NRTIs long term who presented with symptomatic hyperlactataemia (long-term NRTI use; lactate >4.0 mmol/L; absence of infectious source; symptoms requiring admission). Data included demographics, medical history, NRTI duration, blood pressure, symptom duration and relevant laboratory data.

RESULTS

Of 79 patients who met inclusion criteria (mean age 38.2 ± 10.5 years, 97% female) there were 46 fatalities (58%). Factors significantly associated with fatality were presence of diabetes mellitus (p = 0.04), lactate ≥10 mmol/L (p = 0.003), pH <7.2 (p = 0.002), creatinine ≥200 μmol/L (p = 0.03) and altered mental status (p = 0.03).

CONCLUSIONS

In this study, NRTI-related symptomatic hyperlactataemia occurred predominantly in females. Mortality was associated with severely elevated lactate (≥10 mmol/L), the degree of acidosis, elevated creatinine, history of diabetes and altered mental status on presentation.

Pharmacogenetics of toxicity, plasma trough concentration and treatment outcome with nevirapine-containing regimen in anti-retroviral-naïve HIV-infected adults: an exploratory study of the TRIANON ANRS 081 trial

The aim of this exploratory study was to investigate in a homogeneous population of anti-retroviral naïve HIV-1-infected adults, the relationships between genetic polymorphisms involved in nevirapine metabolism [CYP2B6 516G>T, 785A>G and 1459C>T; CYP3A5 6986A>G (CYP3A5*3)], transport (ABCB1 2677G>T/A and 3435C>T), and antigen recognition (HLA-DRB1*0101), and the hepatic and/or cutaneous toxicity occurring within the first 8 or 72 weeks of treatment, plasma trough concentrations (C(trough) ) at week 8 and immuno-virological response to nevirapine at week 24. Associations between genetic polymorphisms and toxicity, C(trough) and response to nevirapine were performed in a population of 72 HIV-1 positive and nevirapine-treated patients followed during 72 weeks, as part of the previous study called: ANRS081 'Trianon' trial. Among the 18 patients who developed toxicity events during the 72 weeks of the study, 12 patients exhibited early toxicity before week 8. No significant association could be evidenced between any of the analysed single nucleotide polymorphisms (SNPs) and nevirapine early or global toxicity, pharmacokinetics and immuno-virological responses even though a possible association between CYP2B6 516G>T and 1459C>T and the trough level of nevirapine was suggested.

[Prevention of HIV transmission (vertical, occupational and non-occupational)]

In these almost thirty years since the epidemic of HIV infection strategies have been developed to decrease the transmission risk when a non-infected person comes into contact with HIV. One of the key landmarks was the use zidovudine was shown to reduce the risk of HIV infection by vertical transmission from 25% to 8% when given from the second trimester of pregnancy, during partum and for several weeks in the newborn. These strategies have been subsequently perfected until achieving vertical transmission rates less than 1%. Almost at the same time, strategies have been developed in an attempt to reduce the risk of transmission of infection after occupational accidents and, in the last few years prophylaxis after non-occupational exposure has been a field of particular concern. Even in this past year several experiments on pre-exposure prophylaxis have been published, which are generating an intense debate on is applicability. In this article, we analyse the state of the art in the prevention of vertical transmission and occupational and non-occupational prophylaxis, from a perspective of applying this in the developed world. We also review the published data on pre-exposure prophylaxis.

Structural alert/reactive metabolite concept as applied in medicinal chemistry to mitigate the risk of idiosyncratic drug toxicity: a perspective based on the critical examination of trends in the top 200 drugs marketed in the United States

Because of a preconceived notion that eliminating reactive metabolite (RM) formation with new drug candidates could mitigate the risk of idiosyncratic drug toxicity, the potential for RM formation is routinely examined as part of lead optimization efforts in drug discovery. Likewise, avoidance of "structural alerts" is almost a norm in drug design. However, there is a growing concern that the perceived safety hazards associated with structural alerts and/or RM screening tools as standalone predictors of toxicity risks may be over exaggerated. In addition, the multifactorial nature of idiosyncratic toxicity is now well recognized based upon observations that mechanisms other than RM formation (e.g., mitochondrial toxicity and inhibition of bile salt export pump (BSEP)) also can account for certain target organ toxicities. Hence, fundamental questions arise such as: When is a molecule that contains a structural alert (RM positive or negative) a cause for concern? Could the molecule in its parent form exert toxicity? Can a low dose drug candidate truly mitigate metabolism-dependent and -independent idiosyncratic toxicity risks? In an effort to address these questions, we have retrospectively examined 68 drugs (recalled or associated with a black box warning due to idiosyncratic toxicity) and the top 200 drugs (prescription and sales) in the United States in 2009 for trends in physiochemical characteristics, daily doses, presence of structural alerts, evidence for RM formation as well as toxicity mechanism(s) potentially mediated by parent drugs. Collectively, our analysis revealed that a significant proportion (∼78-86%) of drugs associated with toxicity contained structural alerts and evidence indicating that RM formation as a causative factor for toxicity has been presented in 62-69% of these molecules. In several cases, mitochondrial toxicity and BSEP inhibition mediated by parent drugs were also noted as potential causative factors. Most drugs were administered at daily doses exceeding several hundred milligrams. There was no obvious link between idiosyncratic toxicity and physicochemical properties such as molecular weight, lipophilicity, etc. Approximately half of the top 200 drugs for 2009 (prescription and sales) also contained one or more alerts in their chemical architecture, and many were found to be RM-positive. Several instances of BSEP and mitochondrial liabilities were also noted with agents in the top 200 category. However, with relatively few exceptions, the vast majority of these drugs are rarely associated with idiosyncratic toxicity, despite years of patient use. The major differentiating factor appeared to be the daily dose; most of the drugs in the top 200 list are administered at low daily doses. In addition, competing detoxication pathways and/or alternate nonmetabolic clearance routes provided suitable justifications for the safety records of RM-positive drugs in the top 200 category. Thus, while RM elimination may be a useful and pragmatic starting point in mitigating idiosyncratic toxicity risks, our analysis suggests a need for a more integrated screening paradigm for chemical hazard identification in drug discovery. Thus, in addition to a detailed assessment of RM formation potential (in relationship to the overall elimination mechanisms of the compound(s)) for lead compounds, effects on cellular health (e.g., cytotoxicity assays), BSEP inhibition, and mitochondrial toxicity are the recommended suite of assays to characterize compound liabilities. However, the prospective use of such data in compound selection will require further validation of the cellular assays using marketed agents. Until we gain a better understanding of the pathophysiological mechanisms associated with idiosyncratic toxicities, improving pharmacokinetics and intrinsic potency as means of decreasing the dose size and the associated "body burden" of the parent drug and its metabolites will remain an overarching goal in drug discovery.

Drug Induced Hypersensitivity and the HLA Complex

Drug-induced hypersensitivity reactions are of major concern and present a burden for national healthcare systems due to their often severe nature, high rate of hospital admissions and high mortality. They manifest with a wide range of symptoms and signs, and can be initiated by a wide range of structurally diverse chemical compounds. The pathophysiological mechanisms underlying hypersensitivity reactions are not well understood, but it is thought that they are immune mediated. MHC region on Chromosome 6 contains many genes with immune function. Classical MHC molecules are highly polymorphic cell surface glycoproteins whose function is to present peptide antigens to T cells. In addition to conferring protection from some diseases, HLA alleles are also associated with an increased risk of other diseases, including drug-induced hypersensitivity. Pharmacogenetic approach to predict the risk of drug-induced hypersensitivity has been established for several drugs. We will discuss the progress of hypersensitivity pharmacogenetics over the last few years and focus on current efforts of the international community to develop consortia which aim to standardize disease phenotypes and to identify affected individuals through international collaborations. In addition, we will discuss the clinical utility of HLA typing as predictive or diagnostic testing for drug-induced hypersensitivity.

Antiretroviral pharmacology: special issues regarding pregnant women and neonates

Antiretrovirals may be used in pregnant women infected with the HIV and their newborns both for treatment of maternal HIV disease and for prevention of mother-to-child transmission of HIV. More than 25 antiretroviral agents in 5 classes have been approved, with new drugs and classes in development. This article reviews current knowledge of the pharmacology of these drugs during pregnancy and in the newborn period, highlighting those pharmacologic issues critical to the safe and effective use of antiretrovirals in these populations.

Personalized medicine for HLA-associated drug-hypersensitivity reactions

Multiple genetic and nongenetic factors can modify the action of a drug, resulting in varied responses to a particular drug across different individuals. Personalized medicine incorporates the comprehensive knowledge of these factors to facilitate the selection of optimal therapy, reduce adverse drug reactions, increase patient compliance and increase the efficiency of therapy. Pharmacogenomics, which integrates the knowledge of an individual’s genetic make-up for diagnostic decisions or therapeutic interventions is closely linked to personalized medicine, and is being increasingly used to prevent adverse drug reactions. There are various reports on genetic associations between particular HLA allotypes and drug hypersensitivities and the strongest associations reported thus far, are with the reverse transcriptase inhibitor, abacavir and HLA-B*5701, the gout prophylactic allopurinol and HLA-B*5801 and the antiepileptic carbamazepine and B*1502, providing a defined disease trigger and suggesting a general mechanism for these associations. Recognizing the strong HLA association, the US FDA has recommended genetic testing before starting abacavir and carbamazepine therapies. To incorporate HLA testing for other drug hypersensitivities and life-threatening reactions it is essential first to establish clear HLA associations, and second, to understand the immune-mechanism by which these drugs induce HLA-linked hypersensitivity. The latter will provide insight into the pathologic mechanisms of drug allergy allowing rational immunotherapy for these life-threatening reactions and the development of alternative drug therapies for hypersensitive patients.

Nevirapine-induced stevens johnson-syndrome and fulminant hepatic failure requiring liver transplantation

We describe a case of nevirapine-induced Stevens-Johnson Syndrome (SJS) and fulminant hepatic failure (FHF) requiring liver transplantation. Five weeks prior to admission, a 57-year-old female with HIV infection had been switched to a nevirapine-based regimen of highly active antiretroviral therapy (HAART) with a CD4 cell count of 695/mm(3). Examination of the explanted native liver at initial transplantation revealed massive hepatic necrosis consistent with drug-induced liver injury. Primary graft nonfunction complicated the early postoperative course and liver retransplantation was required. On follow-up 2 years later, she remains in good health with an undetectable viral load on an efavirenz-based regimen of HAART. To our knowledge, this is the first report of successful liver transplantation following SJS and FHF.

Quantifying the metabolic activation of nevirapine in patients by integrated applications of NMR and mass spectrometries

Nevirapine (NVP), an antiretroviral drug, is associated with idiosyncratic hepatotoxicity and skin reactions. Metabolic pathways of haptenation and immunotoxicity mechanisms have been proposed. NVP is metabolized by liver microsomes to a reactive intermediate that binds irreversibly to protein and forms a GSH adduct. However, no reactive metabolite of NVP, trapped as stable thioether conjugates, has hitherto been identified in vivo. This study has defined the metabolism of NVP with respect to reactive intermediate formation in patients and a rat model of NVP-induced skin reactions. An integrated NMR and mass spectrometry approach has been developed to discover and quantify stable urinary metabolite biomarkers indicative of NVP bioactivation in patients. Two isomeric NVP mercapturates were identified in the urine of HIV-positive patients undergoing standard antiretroviral chemotherapy. The same conjugates were found in rat bile and urine. The mercapturates were isolated from rat bile and characterized definitively by NMR as thioethers substituted at the C-3 and exocyclic C-12 positions of the methylpyrido ring of NVP. It is proposed that NVP undergoes bioactivation to arene oxide and quinone methide intermediates. The purified major mercapturate was quantified by NMR and used to calibrate a mass spectrometric assay of the corresponding metabolite in patient urine. This is the first evidence for metabolic activation of NVP in humans, and only the second minimum estimate in patients of bioactivation of a widely prescribed drug associated with idiosyncratic toxicities. The method can be used as a template for comparative estimations of bioactivation of any drug in patients.

HLA-B*3505 allele is a strong predictor for nevirapine-induced skin adverse drug reactions in HIV-infected Thai patients

OBJECTIVE

Investigation of a possible involvement of differences in human leukocyte antigens (HLA) in the risk of nevirapine (NVP)-induced skin rash among HIV-infected patients.

METHODS

A step-wise case-control association study was conducted. The first set of samples consisted of 80 samples from patients with NVP-induced skin rash and 80 samples from NVP-tolerant patients. These patients were genotyped for the HLA-A, HLA-B, HLA-C, HLA-DRB1, HLA-DQB1, and HLA-DPB1 by a sequence-based HLA typing method. Subsequently, we verified HLA alleles that showed a possible association in the first screening using an additional set of samples consisting of 67 cases with NVP-induced skin rash and 105 controls.

RESULTS

An HLA-B*3505 allele revealed a significant association with NVP-induced skin rash in the first and second screenings. In the combined data set, the HLA-B*3505 allele was observed in 17.5% of the patients with NVP-induced skin rash compared with only 1.1% observed in NVP-tolerant patients [odds ratio (OR)=18.96; 95% confidence interval (CI)=4.87-73.44, Pc=4.6x10] and 0.7% in general Thai population (OR=29.87; 95% CI=5.04-175.86, Pc=2.6x10). The logistic regression analysis also indicated HLA-B*3505 to be significantly associated with skin rash with OR of 49.15 (95% CI=6.45-374.41, P=0.00017).

CONCLUSION

A strong association between the HLA-B*3505 and NVP-induced skin rash provides a novel insight into the pathogenesis of drug-induced rash in the HIV-infected population. On account of its high specificity (98.9%) in identifying NVP-induced rash, it is possible to utilize the HLA-B*3505 as a marker to avoid a subset of NVP-induced rash, at least in Thai population.

Persistent high nevirapine blood level with DRESS syndrome 12 days after interruption of antiretroviral therapy

Nevirapine is an antiretroviral agent associated with drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome. Such a case in an immunocompetent woman recently treated with nevirapine for postexposure HIV prophylaxis is reported here. Despite a period of 12 days after interruption of treatment, a high blood level of nevirapine was still observed.

Unexpected Hepatotoxicity of Rifampin and Saquinavir/Ritonavir in Healthy Male Volunteers

OBJECTIVES: Rifampin is a potent inducer of the cytochrome P450 3A4 isoenzyme (CYP3A4) that metabolizes most protease inhibitor (PI) antiretrovirals. This study was designed to evaluate the steady-state pharmacokinetics and tolerability of the coadministration of the PIs saquinavir and ritonavir (a CYP3A4 inhibitor used as a pharmacoenhancer of other PIs) and rifampin when coadministered in healthy HIV-negative volunteers. METHODS: In an open-label, randomized, one sequence, two-period crossover study involving 28 healthy HIV-negative volunteers, arm 1 was randomized to receive saquinavir/ritonavir 1000/100 mg twice daily while arm 2 received rifampin 600 mg once daily for 14 days. Both arms were then to receive concomitant saquinavir/ritonavir and rifampin for 2 additional weeks. Vital signs, electrocardiography, laboratory analyses, and blood levels of total saquinavir, ritonavir, rifampin, and desacetyl-rifampin, the primary metabolite of rifampin, were measured. RESULTS: In arm 1, 10/14 (71%) and, in arm 2, 11/14 (79%) participants completed the first study phase; eight participants in arm 1 and nine in arm 2 went on to receive both saquinavir/ritonavir and rifampin. Following substantial elevations (>/= grade 2) in hepatic transaminases in participants receiving the coadministered agents, the study was discontinued prematurely. Two participants in arm 1 displayed moderate elevations after five and four doses of rifampin, respectively. In arm 2, all participants experienced severe elevations within 4 days of initiating saquinavir/ritonavir. Clinical symptoms (e.g., nausea, vomiting, abdominal pain, and headache) were more common and severe in arm 2. Clinical symptoms abated and transaminases normalized following drug discontinuation. Limited pharmacokinetic data suggest a possible relationship between transaminase elevation and elevated rifampin and desacetyl-rifampin concentrations. CONCLUSIONS: Although not confirmed in HIV-infected patients, the data indicate that rifampin should not be coadministered with saquinavir/ritonavir.

[Toxicogenetics of antiretroviral treatment (II): neurotoxicity, hepatotoxicity, lactic acidosis, kidney damage, and other adverse effects of antiretroviral drugs]

Several pharmacogenetics studies have analyzed the influence of specific genetic polymorphisms on the toxicity of antiretroviral treatment. The present review describes some of the adverse effects of antiretroviral drugs in which a genetic predisposition may be involved: efavirenz-induced neurological toxicity, generally associated with the 516G>T polymorphism of liver enzyme cytochrome P450 2B6 (CYP2B6); hypersensitivity reactions to nevirapine, associated with specific alleles of major histocompatibility complex, mainly the HLA-DRB1*0101 allele, which, in combination with a high CD4 lymphocyte count, has been associated with systemic reactions and hepatitis in Caucasians, and the HLA-Cw8 allele, which is associated with hypersensitivity reactions in persons from the Italian island of Sardinia and from Japan; nevirapine-induced hepatotoxicity associated with the C>T polymorphism in position 3435T of the ABCB1 (MDR-1) gene codifying for glycoprotein P (lower risk); hyperbilirubinemia in patients exposed to atazanavir or indinavir carrying the UGT1A1*28 polymorphism; peripheral neuropathy with nucleoside analogues associated with haplogroup T of the mitochondrial genome (higher risk) and with the HFE C282Y genotype of the hemochromatosis gene (lower risk); the mutation in codon 964 (R964C) of the POLG gene that codifies the mitochondrial polymerase DNA gamma described in a Thai patient with lactic acidosis; the ABCC2 gene haplotypes associated with tenofovir-induced proximal tubulopathy, and the risk of pancreatitis in persons with mutations in the CFTR and SPINK-1 genes.

Pharmacogenetic information derived from analysis of HLA alleles

A large amount of pharmacogenetic information has, in particular, accumulated on the association between human leukocyte antigen (HLA) alleles and hypersensitivity to certain drugs. Prospective HLA typing has dramatically reduced the risk of abacavir hypersensitivity because of its strong association with HLA-B*5701. Significant predisposition to nevirapine hypersensitivity has been reported in Caucasian Australians harboring HLA-DRB1*0101 with high CD4+ T-cell counts, and Sardinians and Japanese harboring HLA-Cw8. A strong association between carbamazepine hypersensitivity and HLA-B*1502 has been reported in Han Chinese. Most Han Chinese individuals with allopurinol-induced severe cutaneous adverse reactions are positive for HLA-B*5801. HLA typing can stratify risk of hypersensitivity to certain drugs and allow personalized treatment, although the patients should be monitored closely even if they are negative for HLA alleles associated with hypersensitivity.

Pharmacogenetics of Anti-HIV Drugs

Pharmacogenetics holds promise in HIV treatment because of the complexity and potential toxicity of multidrug therapies that are prescribed for long periods. Thus far, few candidate genes have been examined for a limited number of allelic variants, but a number of confirmed associations have already emerged. A change in paradigm emerges from the availability of the HapMap, the wealth of data on less-common genetic polymorphisms, and new genotyping technology. This review presents a comprehensive analysis of the existing literature on pharmacogenetic determinants of antiretroviral drug exposure, drug toxicity, as well as genetic markers associated with the rate of disease progression. It is expected that larger-scale comprehensive genome approaches will profoundly change the landscape of knowledge in the future.

Drug hypersensitivity in HIV

PURPOSE OF REVIEW

Drug hypersensitivity has been reported to occur 100 times more commonly in those living with HIV. In the first decade of HIV treatment, this mainly involved drugs used to treat HIV-related infections but now primarily includes drugs used to treat HIV. This review focuses on the current knowledge of the epidemiology, pathophysiology and clinical features of drug hypersensitivity reactions of drugs used in the management of the HIV-infected patient.

RECENT FINDINGS

Our understanding of the immunogenetics and host predisposition to drug hypersensitivity has been advanced considerably by the antiretroviral drugs abacavir and nevirapine. The association of abacavir hypersensitivity reaction with HLA-B*5701 has been particularly important and provides a basis for genetic screening in the clinic setting.

SUMMARY

The increased predisposition of drug hypersensitivity disease in HIV will continue to provide a fertile ground for study of the diverse and complex processes that drive its pathophysiology. Our knowledge of drug hypersensitivity will also increase as the expanding armentarium of antiretroviral therapy is applied to more diverse populations in the developing world. The potential for widespread implementation of HLA-B*5701 screening for abacavir hypersensitivity will set an important precedent for bringing individualized medicine to the clinic and the use of genetic testing to improve drug safety.

Determinants of nevirapine hypersensitivity and its effect on the association between hepatitis C status and mortality in antiretroviral drug-naive HIV-positive patients

OBJECTIVE

To assess risks factors and outcomes associated with nevirapine hypersensitivity reactions, and to determine the effect of hypersensitivity as a modifier of the association between hepatitis C virus (HCV) infection and mortality among antiretroviral drug-naive patients.

METHODS

The primary endpoint was hypersensitivity reactions in a population-based cohort of antiretroviral therapy-naive HIV-individuals, 18 years or older in British Columbia, Canada, who started triple antiretroviral therapy with nevirapine between May 1997 and June 2003. Univariate and multivariate analyses were performed to identify predictors of nonaccidental mortality in the subgroup of patients with known HCV serostatus.

RESULTS

A total of 66 (9.6%) of 685 patients met the definition for hypersensitivity reactions. In the univariate logistic regression analysis, no variables were identified as risk factors. In multivariate survival analyses conducted to identify characteristics associated with nonaccidental mortality, patients with both HCV coinfection and hypersensitivity reactions had a higher risk of death (hazard ratio, 7.12; 95% confidence interval, 2.73-18.53; P < 0.001) compared with those who did not have HCV coinfection or hypersensitivity reaction.

CONCLUSION

Results of this study suggest that the hypersensitivity reaction behaves as an effect modifier of the association between HCV infection and mortality in this cohort of antiretroviral drug-naive HIV-positive patients. These results support the current recommendation against the use of nevirapine in HIV/HCV-coinfected patients.