abacavir and Drug-Related-Side-Effects-and-Adverse-Reactions

Individuals vary in their susceptibility to adverse reactions to medications, some of which can be potentially life-threatening. Idiosyncratic drug toxicity (IDT) has been shown to be strongly associated to specific polymorphisms in genes encoding human leukocyte antigens (HLAs) by recent genome-wide association studies. However, the pathogenic mechanisms governing such reactions remain unclarified, at least in part because of a lack of suitable experimental animal models to assess IDT. This review describes our work on the specific allele/drug combination of HLA-B*57:01 and abacavir, an antiretroviral drug targeting the human immunodeficiency virus. As abacavir is known to trigger an HLA-dependent immune response, we engineered a transgenic mouse model-HLA-Tg-by partially substituting the mouse HLA sequence for the corresponding human sequence. Local abacavir exposure was found to trigger a significant immune response in an HLA-dependent manner, and oral administration induced liver injury partially via concurrent activation of the innate immune system. Additionally, we developed a technique for evaluating structural alterations in HLA complexes resulting from drug exposure based on phage display to ensure specificity. Further scrutiny of the mechanism(s) underlying drug-induced immune reactions using the HLA-Tg model, as well as enhanced methods for predicting adverse event incidence, are anticipated to help resolve issues surrounding HLA-associated drug hypersensitivity.

Topics: Alleles; Animals; Anti-HIV Agents; Dideoxynucleosides; Disease Models, Animal; Drug Hypersensitivity; Drug-Related Side Effects and Adverse Reactions; Genome-Wide Association Study; HLA Antigens; HLA-B Antigens; Humans; Individuality; Mice; Polymorphism, Genetic

Various types of transgenic mice carrying either class I or II human leukocyte antigen (HLA) molecules are readily available, and reports describing their use in a variety of studies have been published for more than 30 years. Examples of their use include the discovery of HLA-specific antigens against viral infection as well as the reproduction of HLA-mediated autoimmune diseases for the development of therapeutic strategies. Recently, HLA transgenic mice have been used to reproduce HLA-mediated idiosyncratic drug toxicity (IDT), a rare and unpredictable adverse drug reaction that can result in death. For example, abacavir-induced IDT has successfully been reproduced in HLA-B*57:01 transgenic mice. Several reports using HLA transgenic mice for IDT have proven the utility of this concept for the evaluation of IDT using various HLA allele combinations and drugs. It has become apparent that such models may be a valuable tool to investigate the mechanisms underlying HLA-mediated IDT. This review summarizes the latest findings in the area of HLA transgenic mouse models and discusses the current challenges that must be overcome to maximize the potential of this unique animal model.

Topics: Alleles; Animals; Antiviral Agents; Dideoxynucleosides; Disease Models, Animal; Drug-Related Side Effects and Adverse Reactions; HLA Antigens; Humans; Mice; Mice, Transgenic; Virus Diseases

Immune-mediated adverse drug reactions (IM-ADRs) are many times more common in HIV-infected patients. Usual offending drugs include antiretroviral and antiinfectives, but the burden of specific drug IM-ADRs is population-specific; changing as new and fixed dose combinations enter the market, and drug-resistance patterns demand. This review considers recent literature on epidemiology, mechanisms, clinical management and prevention of IM-ADRs amongst persons living with HIV/AIDS.. Epidemiological studies continue to describe high rates of delayed hypersensitivity to known offenders, as well as similar reactions in preexposure prophylaxis. IM-ADRs to oral and injectable integrase strand transfer inhibitors are reported with expanding use. The clinical spectrum and management of IM-ADRs occurring in HIV-infected populations is similar to uninfected; with exceptions such as a recently described severe delayed efavirenz DILI with high mortality. Furthermore, the context can be unique, such as the lower than expected mortality in a Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) cohort from a HIV/TB high burden setting. Programmatic data showing the near complete elimination of Abacavir drug hypersensitivity syndrome following implementation of HLA-B57:01 screening is a stellar example of how prevention is possible with mechanistic insight.. IM-ADRs remain a challenge in persons living with HIV. The complexities posed by polypharmacy, overlapping drug toxicities, drug interactions, overlap of IM-ADRs with other diseases, limited alternative drugs, and vulnerable patients with advanced immunosuppression with high mortality, necessitate increased use of drug provocation testing, treat-through and desensitization strategies. There is an urgent need for improved diagnostics and predictive biomarkers for prevention, or to guide treat-through, rechallenge and desensitization approaches.

Topics: Allergens; Anti-Infective Agents; Anti-Retroviral Agents; Biomarkers; Dideoxynucleosides; Drug Hypersensitivity; Drug-Related Side Effects and Adverse Reactions; Genetic Predisposition to Disease; Genetic Testing; HIV Infections; HIV-1; HLA-B Antigens; Humans; Immunization

Adverse drug reactions (ADRs) are considered as an important cause of morbidity and mortality. The hypersensitivity reactions are immune-mediated ADRs, which are dose-independent, unpredictable and have been associated with several HLA alleles. The present review aimed to describe HLA alleles that have been associated with different ADRs in populations worldwide, the recommendations of regulatory agencies and pharmacoeconomic information and databases for the study of HLA alleles in pharmacogenetics. A systematic search was performed in June 2016 of articles relevant to this issue in indexed journals and in scientific databases (PubMed and PharmGKB). The information of 95 association studies found was summarized. Several HLA alleles and haplotypes have been associated with ADRs induced mainly by carbamazepine, allopurinol, abacavir and nevirapine, among other drugs. Years with the highest numbers of publications were 2013 and 2014. The majority of the reports have been performed on Asians and Caucasians, and carbamazepine was the most studied ADR drug inducer. Two HLA alleles' databases are described, as well as the recommendations of the U.S. Food and Drug Administration, the European Medicine Agency and the Clinical Pharmacogenetics Implementation Consortium. Pharmacoeconomic studies on this issue are also mentioned. The strongest associations remain for HLA-B*58:01, HLA-B*57:01, HLA-B*15:02 and HLA-A*31:01 but only in certain populations; therefore, studies on different ethnic groups would be useful. Due to the improvement of drug therapy and the economic benefit that HLA screening represents, investigations on HLA alleles associated with ADR should continue.

Topics: Alleles; Allopurinol; Carbamazepine; Dideoxynucleosides; Drug-Related Side Effects and Adverse Reactions; Economics, Pharmaceutical; HLA Antigens; Humans; Nevirapine

Concerns exist about the toxicity of drugs used in the implementation of large-scale antiretroviral programmes, and documentation of antiretroviral toxicity is essential. We did a systematic review and meta-analysis of adverse events among children and adolescents receiving regimens that contain abacavir, a widely used antiretroviral drug.. We searched bibliographic databases and abstracts from relevant conferences from Jan 1, 2000, to March 1, 2015. All experimental and observational studies of HIV-infected patients aged 0-18 years who used abacavir, were eligible. Incidence of adverse outcomes in patients taking abacavir (number of new events in a period divided by population at risk at the beginning of the study) and relative risks (RR) compared with non-abacavir regimens were pooled with random effects models.. Of 337 records and 21 conference abstracts identified, nine studies (eight full-text articles and one abstract) collected information about 2546 children, of whom 1769 (69%) were on abacavir regimens. Among children and adolescents taking abacavir, hypersensitivity reactions (eight studies) had a pooled incidence of 2·2% (95% CI 0·4-5·2); treatment switching or discontinuation (seven studies) pooled incidence was 10·9% (2·1-24·3); of grade 3-4 adverse events (six studies) pooled incidence was 9·9% (2·4-20·9); and adverse events other than hypersensitivity reaction (six studies) pooled incidence was 21·5% (2·8-48·4). Between-study inconsistency was significant for all outcomes (p<0·0001 for all inconsistencies). Incidence of death (four studies) was 3·3% (95% CI 1·5-5·6). In the three randomised clinical trials with comparative data, no increased risk of hypersensitivity reaction (pooled RR 1·08; 95% CI 0·19-6·15), grade 3 or 4 events (0·79 [0·44-1·42]), or death (1·72 [0·77-3·82]) was noted for abacavir relative to non-abacavir regimens. None of the reported deaths were related to abacavir.. Abacavir-related toxicity occurs early after ART initiation and is manageable. Abacavir can be safely used for first-line or second-line antiretroviral regimens in children and adolescents, especially in sub-Saharan Africa were HLA B5701 genotype is rare.. WHO.

Topics: Adolescent; Anti-HIV Agents; Child; Child Health Services; Child, Preschool; Dideoxynucleosides; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Therapy, Combination; Drug-Related Side Effects and Adverse Reactions; HIV Infections; Humans; Observational Studies as Topic; Practice Guidelines as Topic

Aldehydes are highly reactive molecules, which can be generated during numerous physiological processes, including the biotransformation of drugs. Several non-P450 enzymes participate in their metabolism albeit alcohol dehydrogenase and aldehyde dehydrogenase are the ones most frequently involved in this process. Endogenous and exogenous aldehydes have been strongly implicated in multiple human pathologies. Their ability to react with biomacromolecules (e.g. proteins) yielding covalent adducts is suggested to be the common primary mechanism underlying the toxicity of these reactive species. Abacavir is one of the options for combined anti-HIV therapy. Although individual susceptibilities to adverse effects differ among patients, abacavir is associated with idiosyncratic hypersensitivity drug reactions and an increased risk of cardiac dysfunction. This review highlights the current knowledge on abacavir metabolism and discusses the potential role of bioactivation to an aldehyde metabolite, capable of forming protein adducts, in the onset of abacavir-induced toxic outcomes.

Topics: Aldehydes; Animals; Anti-HIV Agents; Biotransformation; Dideoxynucleosides; Drug Hypersensitivity; Drug-Related Side Effects and Adverse Reactions; Heart Diseases; Humans

With the rapid development of pharmacogenetics, more and more studies have shown evidence in the association between polymorphisms at the human leukocyte antigen (HLA) loci and severe adverse drug reactions (SADRs). Several HLA-B alleles proved to be associated with SADRs for drugs such as carbamazepine, allopurinol, lamotrigine, and flucloxacillin. The USA Food and Drug Administration (FDA) has even recommended routine screening for HLA-B allele before the use of abacavir and carbamazepine. With the completion of human genome project and the Hapmap project, several new pharmacogenetics approaches such as genome-wide association study (GWAS) have emerged. These newly developed methods will undoubtedly accelerate the identification and clinical utilization of the pharmacogenetic biomakers. In addition, the immunogenetic mechanisms by which the HLA alleles cause SADRs are explored at the cellular and molecular level. This review focuses on the recent progresses in HLA alleles and ADRs regarding both the clinical translation and modern pharmacogenetic methods.

Topics: Allopurinol; Carbamazepine; Dideoxynucleosides; Drug-Related Side Effects and Adverse Reactions; Genome-Wide Association Study; HLA Antigens; Humans; Pharmacogenetics

With the advent of Twenty-First century, more and more genome-wide association studies (GWAS) showed that idiosyncratic adverse drug reactions (ADRs) were closely related with human leukocyte antigen (HLA) alleles, such as the associations of abacavir-HLA-B*5701, allopurinol-HLA-B*5801, and carbamazepine-HLA-B*1502, etc. To explore the mechanisms of these idiosyncratic drug reactions, hapten hypothesis, danger signal hypothesis, pharmacological interaction (P-I) concept and autoimmune mechanism are proposed. In this paper, recent GWAS studies on the HLA-mediated adverse drug reactions and underlying mechanism are reviewed in detail.

Topics: Alleles; Allopurinol; Anti-HIV Agents; Anticonvulsants; Carbamazepine; Dideoxynucleosides; Drug Hypersensitivity Syndrome; Drug-Related Side Effects and Adverse Reactions; Enzyme Inhibitors; Genome-Wide Association Study; HLA Antigens; HLA-B Antigens; HLA-B15 Antigen; Humans; Stevens-Johnson Syndrome

Drug hypersensitivity reactions and severe cutaneous adverse drug reactions, such as Stevens-Johnson syndrome and toxic epidermal necrolysis, are examples of serious adverse drug reactions mediated through a combination of metabolic and immunological mechanisms that could traditionally not have been predicted based on the pharmacological characteristics of the drug alone. The discovery of new associations between these syndromes and specific HLA has created the promise that risk for these reactions could be predicted through pharmacogenetic screening, thereby avoiding serious morbidity and mortality associated with these types of drug reactions. Despite this, several hurdles exist in the translation of these associations into pharmacogenetic tests that could be routinely used in the clinical setting. HLA-B*5701 screening to prevent abacavir hypersensitivity syndrome is an example of a test now in widespread routine clinical use in the developed world.

Topics: Diagnostic Uses of Chemicals; Dideoxynucleosides; Drug Hypersensitivity; Drug-Related Side Effects and Adverse Reactions; Forecasting; HLA-B Antigens; Humans; Pharmaceutical Preparations; Pharmacogenetics; Stevens-Johnson Syndrome

Pharmacogenetics (PGX) is the study of drug response as a function of an individual's DNA. PGX is often viewed as an extension of disease association genetics, and although this information may be related, it is not the study of drug response. Although medicines are used to treat diseases, the value of strategies that identify and incorporate DNA biomarkers associated with clinical efficacy, or DNA biomarkers for untoward clinical responses, can be applied directly to pharmaceutical pipelines. The growth of adverse event PGX studies involving marketed medicines generally uses relatively large numbers of affected patients, but has been productive. However, the two critical strategies for pipeline genetics must make use of fewer patients: (1) the early identification of efficacy signals so that they can be applied early in development for targeted therapies and (2) identification of safety signals that can subsequently be validated prospectively during development using the least number of patients with adverse responses. Assumptions are often made that large numbers of patients are necessary to recognize PGX hypotheses and to validate DNA biomarkers. In some ways, pipeline pharmacogenetics may be viewed as the opposite of current genome-wide scanning designs. The goal is to obtain PGX signals in as few patients as possible, and then validate PGX hypotheses for specificity and sensitivity as development trials go forward--not using hundreds of thousand of markers to detect strong linkage disequilibrium signals in thousands of patients and their controls. Drug development takes 5-7 years for a drug candidate to traverse to registration--and this is similar to the timeframe for validating genetic biomarkers using sequential clinical trials. Two important examples are discussed, the association of APOE genotypes to the demonstration of actionable efficacy signals for the use of rosiglitazone for Alzheimer's disease; and the identification of HLA-B(*)5701 as a highly sensitive and specific predictive marker for abacavir treated patients who will develop hypersensitivity syndrome (HSS). The rosiglitazone study prevented pipeline attrition by changing the interpretation of a critical Phase IIB proof of concept study (2005) from a failed study, to a positive efficacy response in a genetically predictable proportion of patients. Now, three years later, a Phase III program of clinical trials using pharmacogenetic designs is months away from completion (late08). If s

Topics: Alzheimer Disease; Apolipoprotein E4; Apolipoproteins E; Biomarkers, Pharmacological; Clinical Trials as Topic; Cost-Benefit Analysis; Dideoxynucleosides; Drug Discovery; Drug Hypersensitivity; Drug-Related Side Effects and Adverse Reactions; Genome-Wide Association Study; Genotype; HLA-B Antigens; Humans; Models, Biological; Pharmacogenetics; Rosiglitazone; Sample Size; Thiazolidinediones

This article provides a general introduction into the field of pharmacogenetics and discusses its opportunities and limits. Pharmacogenetic research explores genetic variability between patients to explain observed differences in effectiveness of a drug therapy or adverse event profiles. Sometimes drug therapy is unfavourable: Patients may respond only partially to a drug therapy, do not respond at all, or suffer from serious adverse events. The reasons for the varying effectiveness of a drug therapy are due to factors like absorption; metabolism, elimination and target interaction. Recent research has led to a better understanding of the molecular genetic mechanisms behind those factors. Numerous new polymorphisms have been described, for example for the beta 2-adrenergic receptor or the cytochrome which can either improve or reduce the response to drug therapy. Two polymorphisms for the tumour necrosis factor alpha have shown to be associated with an increased risk of serious adverse events (hypersensibility: fever, rash, gastrointestinal symptoms) if treated with abacavir (HIV-treatment). Pharmacogenetic tests provide information about certain polymorphisms and raise the hope for an individualized pharmacotherapy. Yet, not only genetic but also environmental factors influence the effectiveness of a therapy. Even though results from research implies that pharmacogenetics has a great potential to maximize the effectiveness of pharmacotherapy and to reduce the incidence of drug-related adverse events, extensive clinical research both on effectiveness and costs is required to assess the true benefits of these exciting new technologies.

Topics: Anti-HIV Agents; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Breast Neoplasms; Cohort Studies; Dideoxynucleosides; Drug Therapy; Drug-Related Side Effects and Adverse Reactions; Female; HIV Infections; Humans; Male; Mutation; Pharmacogenetics; Polymorphism, Genetic; Prognosis; Research; Reverse Transcriptase Inhibitors; Trastuzumab

Bictegravir, co-formulated with emtricitabine and tenofovir alafenamide, has shown good efficacy and tolerability, and similar bone, renal, and lipid profiles to dolutegravir, abacavir, and lamivudine, in treatment-naive adults with HIV-1 infection, without development of treatment-emergent resistance. Here, we report 48-week results of a phase 3 study investigating switching to bictegravir, emtricitabine, and tenofovir alafenamide from dolutegravir, abacavir, and lamivudine in virologically suppressed adults with HIV-1 infection.. In this multicentre, randomised, double-blind, active-controlled, non-inferiority, phase 3 trial, HIV-1-infected adults were enrolled at 96 outpatient centres in nine countries. Eligible participants were aged 18 years or older and on a regimen of 50 mg dolutegravir, 600 mg abacavir, and 300 mg lamivudine (fixed-dose combination or multi-tablet regimen); had an estimated glomerular filtration rate of 50 mL/min or higher; and had been virologically suppressed (plasma HIV-1 RNA <50 copies per mL) for 3 months or more before screening. We randomly assigned participants (1:1), using a computer-generated randomisation sequence, to switch to co-formulated bictegravir (50 mg), emtricitabine (200 mg), and tenofovir alafenamide (25 mg; herein known as the bictegravir group), or to remain on dolutegravir, abacavir, and lamivudine (herein known as the dolutegravir group), once daily for 48 weeks. The investigators, participants, study staff, and individuals assessing outcomes were masked to treatment assignment. The primary endpoint was the proportion of participants with plasma HIV-1 RNA of 50 copies per mL or higher at week 48 (according to the US Food and Drug Administration snapshot algorithm); the prespecified non-inferiority margin was 4%. The primary efficacy and safety analyses included all participants who received at least one dose of study drug. This study is ongoing but not actively recruiting participants and is in the open-label extension phase, wherein participants are given the option to receive bictegravir, emtricitabine, and tenofovir alafenamide for an additional 96 weeks. This trial is registered with ClinicalTrials.gov, number NCT02603120.. Between Nov 11, 2015, and July 6, 2016, 567 participants were randomly assigned and 563 were treated (282 received bictegravir, emtricitabine, and tenofovir alafenamide, and 281 received dolutegravir, abacavir, and lamivudine). Switching to the bictegravir regimen was non-inferior to remaining on dolutegravir, abacavir, and lamivudine for the primary outcome: three (1%) of 282 in the bictegravir group had HIV-1 RNA of 50 copies per mL or higher at week 48 versus one (<1%) of 281 participants in the dolutegravir group (difference 0·7%, 95·002% CI -1·0 to 2·8; p=0·62). Treatment-related adverse events were recorded in 23 (8%) participants in the bictegravir group and 44 (16%) in the dolutegravir group. Treatment was discontinued because of adverse events in six (2%) participants in the bictegravir group and in two (1%) participants in the dolutegravir group.. The fixed-dose combination of bictegravir, emtricitabine, and tenofovir alafenamide might provide a safe and efficacious option for ongoing treatment of HIV-1 infection.. Gilead Sciences.

Topics: Adult; Aged; Amides; Anti-HIV Agents; Dideoxynucleosides; Double-Blind Method; Drug Substitution; Drug Therapy, Combination; Drug-Related Side Effects and Adverse Reactions; Emtricitabine; Female; Heterocyclic Compounds, 3-Ring; Heterocyclic Compounds, 4 or More Rings; HIV Infections; HIV Seropositivity; HIV-1; Humans; Lamivudine; Male; Middle Aged; Oxazines; Piperazines; Pyridones; Sustained Virologic Response; Tenofovir; Viral Load; Young Adult

Antiretroviral therapy (ART) adherence is critical for successful HIV treatment outcomes. Once-daily dosing could improve adherence. Plasma concentrations of once-daily vs twice-daily abacavir + lamivudine are bioequivalent in children, but no randomized trial has compared virological outcomes.. Children taking abacavir + lamivudine-containing first-line regimens twice daily for more than 36 weeks in the ARROW trial (NCT02028676, ISRCTN24791884) were randomized to continue twice-daily vs move to once-daily abacavir + lamivudine (open-label). Co-primary outcomes were viral load suppression at week 48 (12% noninferiority margin, measured retrospectively) and lamivudine or abacavir-related grade 3/4 adverse events.. Six hundred and sixty-nine children (median 5 years, range 1-16) were randomized to twice daily (n = 333) vs once daily (n = 336) after median 1.8 years on twice-daily abacavir + lamivudine-containing first-line ART. Children were followed for median 114 weeks. At week 48, 242/331 (73%) twice daily vs 236/330 (72%) once daily had viral load less than 80 copies/ml [difference -1.6% (95% confidence interval -8.4,+5.2%) P = 0.65]; 79% twice daily vs 78% once daily had viral load less than 400 copies/ml (P = 0.76) (week 96 results similar). One grade 3/4 adverse event was judged uncertainly related to abacavir + lamivudine (hepatitis; once daily). At week 48, 9% twice daily vs 10% once daily reported missing one or more ART pills in the last 4 weeks (P = 0.74) and 8 vs 8% at week 96 (P = 0.90). Carers strongly preferred once-daily dosing. There was no difference between randomized groups in postbaseline drug-resistance mutations or drug-susceptibility; WHO 3/4 events; ART-modifying, grade 3/4 or serious adverse events; CD4% or weight-for-age/height-for-age (all P > 0.15).. Once-daily abacavir + lamivudine was noninferior to twice daily in viral load suppression, with similar resistance, adherence, clinical, immunological and safety outcomes. Abacavir + lamivudine provides the first once-daily nucleoside backbone across childhood that can be used to simplify ART.

Topics: Adolescent; Africa; Anti-HIV Agents; Child; Child, Preschool; Dideoxynucleosides; Drug Resistance, Viral; Drug-Related Side Effects and Adverse Reactions; Female; HIV Infections; Humans; Immune Reconstitution; Infant; Lamivudine; Male; Medication Adherence; Sustained Virologic Response; Treatment Outcome

Abacavir hypersensitivity syndrome (ABC HSS) is strongly associated with carriage of human leukocyte antigen (HLA)-B*57:01, which has a 100% negative predictive value for the development of ABC HSS. However, 45% of individuals who carry HLA-B*57:01 can tolerate ABC. We investigated immune and non-immune related genes in ABC HSS (n = 95) and ABC tolerant (n = 43) HLA-B*57:01 + patients to determine other factors required for the development of ABC HSS. Assignment of phenotype showed that ABC HSS subjects were significantly less likely than tolerants to carry only ERAP1 hypoactive trimming allotypes (p = 0.02). An altered self-peptide repertoire model by which abacavir activates T cells is in keeping with observation that endoplasmic reticulum aminopeptidase 1 (ERAP1) allotypes that favour efficient peptide trimming are more common in ABC HSS patients compared to patients who tolerate ABC. Independently, non-specific immune activation via soluble cluster of differentiation antigen 14 (sCD14) may also influence susceptibility to ABC HSS.

Topics: Allergens; Aminopeptidases; Anti-HIV Agents; Dideoxynucleosides; Drug Hypersensitivity Syndrome; Drug-Related Side Effects and Adverse Reactions; Female; Genetic Association Studies; Genetic Predisposition to Disease; Genotype; HIV Infections; HIV-1; HLA-B Antigens; Humans; Lipopolysaccharide Receptors; Male; Minor Histocompatibility Antigens; Phenotype; Retrospective Studies

Topics: Adult; Anti-HIV Agents; Dideoxynucleosides; Drug Combinations; Drug Therapy, Combination; Drug-Related Side Effects and Adverse Reactions; Female; Heterocyclic Compounds, 3-Ring; HIV Infections; Humans; Illinois; Lamivudine; Male; Middle Aged; Oxazines; Piperazines; Prisoners; Prisons; Pyridones; Retrospective Studies; Treatment Outcome

Topics: Aged; Anti-HIV Agents; Arthralgia; CD8-Positive T-Lymphocytes; Dideoxynucleosides; Drug Hypersensitivity; Drug-Related Side Effects and Adverse Reactions; Gene Expression Profiling; Headache; HLA-B Antigens; Humans; Immunologic Memory; Lymphocyte Activation; Male; Myalgia; Patch Tests; Single-Cell Analysis; Skin

Adverse drug reactions (ADRs) are a major obstacle to drug development, and some of these, including hypersensitivity reactions to the HIV reverse transcriptase inhibitor abacavir (ABC), are associated with HLA alleles, particularly HLA-B*57:01. However, not all HLA-B*57:01+ patients develop ADRs, suggesting that in addition to the HLA genetic risk, other factors may influence the outcome of the response to the drug. To study HLA-linked ADRs in vivo, we generated HLA-B*57:01-Tg mice and show that, although ABC activated Tg mouse CD8+ T cells in vitro in a HLA-B*57:01-dependent manner, the drug was tolerated in vivo. In immunocompetent Tg animals, ABC induced CD8+ T cells with an anergy-like phenotype that did not lead to ADRs. In contrast, in vivo depletion of CD4+ T cells prior to ABC administration enhanced DC maturation to induce systemic ABC-reactive CD8+ T cells with an effector-like and skin-homing phenotype along with CD8+ infiltration and inflammation in drug-sensitized skin. B7 costimulatory molecule blockade prevented CD8+ T cell activation. These Tg mice provide a model for ABC tolerance and for the generation of HLA-B*57:01-restricted, ABC-reactive CD8+ T cells dependent on both HLA genetic risk and immunoregulatory host factors.

Topics: Animals; Anti-HIV Agents; CD8-Positive T-Lymphocytes; Dideoxynucleosides; Disease Models, Animal; Drug Hypersensitivity; Drug Tolerance; Drug-Related Side Effects and Adverse Reactions; Female; HLA-B Antigens; Humans; In Vitro Techniques; Lymphocyte Activation; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Reverse Transcriptase Inhibitors

Adverse drug reactions have been linked with genetic polymorphisms in HLA genes in numerous different studies. HLA proteins have an essential role in the presentation of self and non-self peptides, as part of the adaptive immune response. Amongst the associated drugs-allele combinations, anti-HIV drug Abacavir has been shown to be associated with the HLA-B*57:01 allele, and anti-epilepsy drug Carbamazepine with B*15:02, in both cases likely following the altered peptide repertoire model of interaction. Under this model, the drug binds directly to the antigen presentation region, causing different self peptides to be presented, which trigger an unwanted immune response. There is growing interest in searching for evidence supporting this model for other ADRs using bioinformatics techniques. In this study, in silico docking was used to assess the utility and reliability of well-known docking programs when addressing these challenging HLA-drug situations. The overall aim was to address the uncertainty of docking programs giving different results by completing a detailed comparative study of docking software, grounded in the MHC-ligand experimental structural data - for Abacavir and to a lesser extent Carbamazepine - in order to assess their performance. Four docking programs: SwissDock, ROSIE, AutoDock Vina and AutoDockFR, were used to investigate if each software could accurately dock the Abacavir back into the crystal structure for the protein arising from the known risk allele, and if they were able to distinguish between the HLA-associated and non-HLA-associated (control) alleles. The impact of using homology models on the docking performance and how using different parameters, such as including receptor flexibility, affected the docking performance were also investigated to simulate the approach where a crystal structure for a given HLA allele may be unavailable. The programs that were best able to predict the binding position of Abacavir were then used to recreate the docking seen for Carbamazepine with B*15:02 and controls alleles. It was found that the programs investigated were sometimes able to correctly predict the binding mode of Abacavir with B*57:01 but not always. Each of the software packages that were assessed could predict the binding of Abacavir and Carbamazepine within the correct sub-pocket and, with the exception of ROSIE, was able to correctly distinguish between risk and control alleles. We found that docking to homology models could p

Topics: Alleles; Carbamazepine; Dideoxynucleosides; Drug-Related Side Effects and Adverse Reactions; HLA Antigens; Humans; Molecular Docking Simulation; Peptides; Risk Factors; Software; Structural Homology, Protein

HLA-B*57:01 is strongly associated with severe adverse drug reaction induced by the anti-HIV drug abacavir (ABC) and antibiotic flucloxacillin. This study was dedicated to establishing a new method for HLA-B*57:01 genotyping and investigating the HLA-B*57:01 distribution pattern in four Chinese populations. A single-tube duplex real-time polymerase chain reaction (PCR) system was established by combining the amplification refractory mutation system and TaqMan probe. The reliability of this assay was validated by comparing the genotyping results with those by sequence-based typing. With this assay, the distribution of HLA-B*57:01 in 354 blood samples from four ethnic groups, namely, Han, Tibetan, Uighur, and Buyei, was determined. A 100% concordance was observed between the results of real-time PCR and sequence-based typing in 50 Uighur samples. As low as 0.016 ng DNA that carried HLA-B*57:01 could be detected with this assay. HLA-B*57:01 carriers identified in 100 Northern Han Chinese, 104 Buyeis, 100 Tibetans, and 50 Uighurs were 0, 1 (0.96%), 3 (3%), and 6 (12%), respectively. The carrier rate of HLA-B*57:01 in Uighur was significantly higher than those in Northern Han (p = .001) and Buyei (p = .005). The newly established real-time PCR assay provides a rapid and reliable tool for HLA-B*57:01 allele screening before the prescription of ABC and flucloxacillin in clinical practice.

Topics: Asian People; Cohort Studies; Dideoxynucleosides; Drug-Related Side Effects and Adverse Reactions; Genetic Testing; Genotype; Genotyping Techniques; HIV Infections; HLA-B Antigens; Humans; Multiplex Polymerase Chain Reaction; Real-Time Polymerase Chain Reaction; Time Factors

The progressing discovery of genetic variants associated with drug-related adverse events has raised expectations for pharmacogenetic tests to improve drug efficacy and safety. To further the use of pharmacogenetics in health care, tests with sufficient potential to improve efficacy and safety, as reflected by good clinical validity and population impact, need to be identified. The potential benefit of pharmacogenetic tests is often concluded from the strength of the association between the variant and the adverse event; measures of clinical validity are generally not reported. This paper describes measures of clinical validity and potential population health impact that can be calculated from association studies. We explain how these measures are influenced by the strength of the association and by the frequencies of the variant and the adverse event. The measures are illustrated using examples of testing for HLA-B*5701 associated with abacavir-induced hypersensitivity and SLCO1B1 c.521T>C (*5) associated with simvastatin-induced adverse events.

Topics: Dideoxynucleosides; Drug Hypersensitivity; Drug-Related Side Effects and Adverse Reactions; Genetic Testing; Genetic Variation; HLA-B Antigens; Humans; Pharmacogenetics; Simvastatin

The HLA-B*57:01 allele is strongly associated with the hypersensitivity reaction to Abacavir (ABC). Therefore, treatment guidelines recommend that patients initiating ABC are preventively tested for the presence of this allele. To date, four different commercial assays based on the real-time quantitative polymerase chain reaction (Q-PCR) technique are available for the detection of HLA-B*57:01: Duplicα-RealTime Reagent Set HLA-B*57:01 by Euroclone, HLA-B*57:01 Real-TM by Sacace Biotechnologies, COBAS AmpliPrep/COBAS TaqMan HLA-B*57:01 Screening Test by Roche Diagnostic, and HLA-B*57:01 by Nuclear Laser Medicine. The study was carried out to compare the performance of the first three commercially available Q-PCR kits in a routine clinical setting. A total of 98 samples from Policlinico Umberto I Hospital were tested. Results obtained by the Duplicα-RealTime Genotyping kit and AmpliPrep/TaqMan system were 100% concordant. In contrast, genotyping by the HLA-B*57:01 Real-TM kit showed poor agreement with the other systems, that is, 12 out of 33 positive samples were detected as HLA-B*57:01 negative. To confirm the correct genotype of these discordant samples, two additional methods with rapid turnaround times and already implemented into routine clinical practice were used, that is, a PCR-based microsequence-specific primer DNA typing test and a laboratory-developed screening test in Q-PCR. All 12 discordant samples were genotyped as HLA-B*57:01-positive samples using these two additional methods in a single-blinded manner, thus confirming the low sensitivity of HLA-B*57:01 Real-TM test. These findings underline the need to compare results obtained with commercial assays before choosing a test suitable for use in a routine clinical laboratory.

Topics: Anti-HIV Agents; Dideoxynucleosides; Drug-Related Side Effects and Adverse Reactions; Female; Genotyping Techniques; HIV Infections; HLA-B Antigens; Humans; Male; Middle Aged; Real-Time Polymerase Chain Reaction

Since the beginning of this century, information on pharmacogenetics appears in the summary of product characteristics (SPC) of drugs. Pharmacogenetic tests particularly concern the enzymes involved in the metabolism of drugs, among which P450 cytochromes. Some patients known as poor metabolisers eliminate some drugs more slowly, causing overdoses and adverse drug reactions (ADRs). The best-known examples are AVK and VKORC1-CYP2C9 or clopidogrel and CYP2C19. In the USA, the tests are recommended before the introduction of these drugs to prevent the occurrence of ADRs. Other tests are also commonly performed to address the toxicity of certain anticancer drugs (DPYD-capecitabine, UGT1A1-irinotecan, TPMT 6-mercaptopurine). Pharmacogenetic testing is also available to identify HLA loci that are very strongly associated with the occurrence of immuno-allergic reactions to a specific drug. The best-known example is HLA-B*5701, strongly associated with hypersensitivity to abacavir, and this test is now always prescribed before the instatement of this drug.

Topics: Antineoplastic Agents; Cytochrome P-450 Enzyme System; Dideoxynucleosides; Drug Hypersensitivity; Drug Overdose; Drug-Related Side Effects and Adverse Reactions; Humans; Pharmacogenetics; Pharmacovigilance

Topics: Antidepressive Agents; Child; Dideoxynucleosides; Drug Hypersensitivity; Drug-Related Side Effects and Adverse Reactions; Evidence-Based Medicine; Genetic Testing; HIV Infections; HLA-B Antigens; Humans; Male; Mercaptopurine; Pharmacogenetics; Precision Medicine; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Primaquine; Purine-Pyrimidine Metabolism, Inborn Errors; Succinylcholine; Warfarin

Antiretroviral therapy (ART) has evolved rapidly since its beginnings. This analysis describes trends in first-line ART use in Asia and their impact on treatment outcomes.. Patients in the TREAT Asia HIV Observational Database receiving first-line ART for ≥ 6 months were included. Predictors of treatment failure and treatment modification were assessed.. Data from 4662 eligible patients was analysed. Patients started ART in 2003-2006 (n = 1419), 2007-2010 (n = 2690) and 2011-2013 (n = 553). During the observation period, tenofovir, zidovudine and abacavir use largely replaced stavudine. Stavudine was prescribed to 5.8% of ART starters in 2012/13. Efavirenz use increased at the expense of nevirapine, although both continue to be used extensively (47.5% and 34.5% of patients in 2012/13, respectively). Protease inhibitor use dropped after 2004. The rate of treatment failure or modification declined over time (22.1 [95%CI 20.7-23.5] events per 100 patient/years in 2003-2006, 15.8 [14.9-16.8] in 2007-2010, and 11.6 [9.4-14.2] in 2011-2013). Adjustment for ART regimen had little impact on the temporal decline in treatment failure rates but substantially attenuated the temporal decline in rates of modification due to adverse event. In the final multivariate model, treatment modification due to adverse event was significantly predicted by earlier period of ART initiation (hazard ratio 0.52 [95%CI 0.33-0.81], p = 0.004 for 2011-2013 versus 2003-2006), older age (1.56 [1.19-2.04], p = 0.001 for ≥ 50 years versus <30 years), female sex (1.29 [1.11-1.50], p = 0.001 versus male), positive hepatitis C status (1.33 [1.06-1.66], p = 0.013 versus negative), and ART regimen (11.36 [6.28-20.54], p<0.001 for stavudine-based regimens versus tenofovir-based).. The observed trends in first-line ART use in Asia reflect changes in drug availability, global treatment recommendations and prescriber preferences over the past decade. These changes have contributed to a declining rate of treatment modification due to adverse event, but not to reductions in treatment failure.

Topics: Adult; Anti-HIV Agents; Antiretroviral Therapy, Highly Active; Asia; Dideoxynucleosides; Drug-Related Side Effects and Adverse Reactions; Female; HIV; HIV Infections; Humans; Male; Nevirapine; Reverse Transcriptase Inhibitors; Stavudine

Stavudine is a commonly used drug in paediatric antiretroviral treatment (ART) regimens. Due to toxicity concerns, however, the drug abacavir has replaced stavudine in first-line paediatric regimens in many countries. We describe the frequency of stavudine toxicity in children receiving ART at a treatment clinic in Soweto, South Africa.. Data on patient characteristics and outcomes of ART were collected from a cohort of 2222 HIV-infected children initiating ART between 2004 and 2008 when stavudine-containing regimens were routinely recommended. At several time-points after treatment initiation, we estimate the proportion of children where an attending clinician discontinued stavudine due to lipodystrophy, pancreatitis, lactic acidosis or peripheral neuropathy. Factors associated with stavudine-related toxicities were identified.. At ART initiation, most children had advanced disease. The majority initiated an efavirenz/lamivudine/stavudine regimen (n = 1422), and 76% of children remained on their initial ART regimen after a median 19.9 months of ART. Replacement of stavudine due to drug toxicity occurred at a rate of 28.8 per 1000 child years on treatment (95% confidence interval = 23.6-35.2). Rates of toxicity increased with treatment duration (in their first year of ART stavudine was replaced in 0.5% of children, but after 3 years stavudine had been changed to abacavir in 12.6% of children). Toxicity was more common in older children and in girls. Lipodystrophy accounted for 87 of 96 toxic events.. Stavudine-associated toxicity resulting in single-drug substitution was uncommon in this cohort, though its frequency increased steadily with ART duration, especially with lipodystrophy. Where drug options are limited, stavudine remains a relatively well tolerated and effective option for children.

Topics: Alkynes; Anti-HIV Agents; Antiretroviral Therapy, Highly Active; Benzoxazines; Child; Child, Preschool; Cohort Studies; Cyclopropanes; Dideoxynucleosides; Drug Substitution; Drug Therapy, Combination; Drug-Related Side Effects and Adverse Reactions; Female; HIV Infections; Humans; Infant; Lamivudine; Male; Retrospective Studies; Risk Factors; South Africa; Stavudine; Time Factors

Drug hypersensitivity reactions are an immune-mediated reaction to otherwise innocuous antigens derived from drugs. These reactions can affect many different organs, with the skin being the commonest. Skin involvement can range in severity with hypersensitivity syndrome (or DRESS) and the blistering reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis), also termed serious cutaneous adverse drug reactions, being the most severe and most feared. There is increasing evidence for the role of the immune system in the pathogenesis of these reactions, with drug-specific T cells having been identified in many patients. Until recently, very little was known about the predisposition to these reactions. However, the availability of more accurate molecular typing methods, and the ability to analyse the whole genome in an unbiased fashion, has led to some remarkable findings of the role of the HLA genes as genomic biomarkers of predisposition. The 'revolution' started with abacavir where the predisposition to hypersensitivity was linked to HLA-B*57:01, which was confirmed in a clinical trial, and where its implementation has shown to reduce the incidence of hypersensitivity in a cost-effective manner. Since then, associations have also been shown for allopurinol (HLA-B*58:01)- and carbamazepine (HLA-B*1502 and HLA-A*3101)-induced serious cutaneous adverse drug reactions. The latter is interesting since the association with HLA-B*1502 is present in certain South-Eastern Asian populations, and the predisposition is phenotype specific (only for SJS/TEN). The utility of this biomarker has been shown in a prospective cohort study performed in Taiwan. By contrast, the association with HLA-A*3101 is seen in more diverse ethnic groups, and predisposes to mild as well more severe cutaneous reactions associated with carbamazepine. It is important to note that strong HLA associations have also been shown with a number of drugs that cause liver injury including flucloxacillin, lumiracoxib, lapatinib and ximelagatran, indicating that the immune system is also important in the pathogenesis of other forms of drug-induced organ toxicity. The crucial question as to whether these HLA alleles are truly causative or acting as surrogate markers of predisposition, however, is still unclear, and will require further investigations in larger patient cohorts, through the use of bioinformatic techniques, fine mapping using next generation sequencing technologies and functional stud

Topics: Allopurinol; Anti-Bacterial Agents; Anti-HIV Agents; Anticonvulsants; Antimetabolites; Biomarkers; Carbamazepine; Chemical and Drug Induced Liver Injury; Dideoxynucleosides; Drug Hypersensitivity; Drug-Related Side Effects and Adverse Reactions; Genome-Wide Association Study; HLA Antigens; HLA-A Antigens; HLA-B Antigens; Humans; Immune System; Predictive Value of Tests; Stevens-Johnson Syndrome

Drug-induced liver injury (DILI) is a leading cause of drugs failing during clinical trials and being withdrawn from the market. Comparative analysis of drugs based on their DILI potential is an effective approach to discover key DILI mechanisms and risk factors. However, assessing the DILI potential of a drug is a challenge with no existing consensus methods. We proposed a systematic classification scheme using FDA-approved drug labeling to assess the DILI potential of drugs, which yielded a benchmark dataset with 287 drugs representing a wide range of therapeutic categories and daily dosage amounts. The method is transparent and reproducible with a potential to serve as a common practice to study the DILI of marketed drugs for supporting drug discovery and biomarker development.

Topics: Animals; Benchmarking; Biomarkers, Pharmacological; Chemical and Drug Induced Liver Injury; Drug Design; Drug Labeling; Drug-Related Side Effects and Adverse Reactions; Humans; Pharmaceutical Preparations; Reproducibility of Results; United States; United States Food and Drug Administration

Drug-induced liver injury (DILI) is a significant concern in drug development due to the poor concordance between preclinical and clinical findings of liver toxicity. We hypothesized that the DILI types (hepatotoxic side effects) seen in the clinic can be translated into the development of predictive in silico models for use in the drug discovery phase. We identified 13 hepatotoxic side effects with high accuracy for classifying marketed drugs for their DILI potential. We then developed in silico predictive models for each of these 13 side effects, which were further combined to construct a DILI prediction system (DILIps). The DILIps yielded 60-70% prediction accuracy for three independent validation sets. To enhance the confidence for identification of drugs that cause severe DILI in humans, the "Rule of Three" was developed in DILIps by using a consensus strategy based on 13 models. This gave high positive predictive value (91%) when applied to an external dataset containing 206 drugs from three independent literature datasets. Using the DILIps, we screened all the drugs in DrugBank and investigated their DILI potential in terms of protein targets and therapeutic categories through network modeling. We demonstrated that two therapeutic categories, anti-infectives for systemic use and musculoskeletal system drugs, were enriched for DILI, which is consistent with current knowledge. We also identified protein targets and pathways that are related to drugs that cause DILI by using pathway analysis and co-occurrence text mining. While marketed drugs were the focus of this study, the DILIps has a potential as an evaluation tool to screen and prioritize new drug candidates or chemicals, such as environmental chemicals, to avoid those that might cause liver toxicity. We expect that the methodology can be also applied to other drug safety endpoints, such as renal or cardiovascular toxicity.

Topics: Animals; Anti-Infective Agents; Anti-Inflammatory Agents; Chemical and Drug Induced Liver Injury; Databases, Factual; Drug-Related Side Effects and Adverse Reactions; Humans; Liver; Models, Biological; Predictive Value of Tests

The availability of high-resolution genetic profiling raises the possibility, during the course of a drug development program, of discovering a subset of patients at particular risk of an adverse drug reaction who might be excluded from subsequent randomization into studies and identified as unsuitable for post-licensing use. Such methods depend on the estimation of the risk of adverse drug reactions for patients with differing genetic profiles followed by an assessment of the risks and benefits of their exposure to the drug. In this paper we explore the performance of a number alternative statistical methods for the estimation of risk in terms of the success of the subsequent exclusion rules. The approaches were evaluated using a single-nucleotide polymorphism dataset concerning HIV patients at risk of hypersensitivity to the drug abacavir. Overall we found that a method based on LASSO performed better than the alternatives that we studied, which included a decision-theoretic Bayesian approach, and that its performance suggested suitability for its prospective implementation.

Topics: Anti-HIV Agents; Bayes Theorem; Clinical Trials as Topic; Dideoxynucleosides; Drug Design; Drug Hypersensitivity; Drug-Related Side Effects and Adverse Reactions; Gene Expression Profiling; Genome, Human; HIV Infections; Humans; Models, Statistical; Polymorphism, Single Nucleotide; Reproducibility of Results; Risk Assessment

Drug-induced hypersensitivity reactions represent a major concern for clinicians, patients, regulators and drug developers. Severe hypersensitivity is associated with high morbidity and mortality, it cannot be predicted from the known pharmacology of the drug and it is usually detected post-marketing when a large number of patients have been exposed to a particular drug. Recent success in developing clinically useful genetic tests that have allowed us to predict the risk of abacavir-induced hypersensitivity has helped to pave the path for a pharmacogenetic approach. However, the loop from identifying a genetic association to improving clinical outcome is still lacking for many drugs. In this commentary, we discuss the progress of hypersensitivity pharmacogenomics over the last decade and point out what remains to be done in the future. The current efforts of the international community are focused on the development of consortia, which aim to standardize disease phenotypes, but also to collect larger numbers of well-phenotyped patients and to pool biological samples through these collaborations. In addition, it is necessary to advance our knowledge of hypersensitivity mechanisms through functional studies, which will lead to the development of predictive and diagnostic tests.

Topics: Dideoxynucleosides; Drug Hypersensitivity; Drug-Related Side Effects and Adverse Reactions; HLA Antigens; Humans; Pharmaceutical Preparations; Pharmacogenetics; Polymorphism, Genetic

Abacavir sulfate (abacavir) is associated with a hypersensitivity reaction (HSR) that affects 5-8% of patients. While serious complications are rare, failure to identify it, or abacavir re-challenge following HSR, can be fatal. Genetic screening for HLA-B*5701 can identify patients who are likely to experience an HSR and reduces the incidence of the reaction.. We assessed the intrinsic and practical value, from the US healthcare system perspective, of prospective HLA-B*5701 screening among a population of antiretroviral-naive patients without elevated risk factors for cardiovascular disease, plasma HIV RNA >100,000 copies/mL, or pre-existing renal insufficiency.. Two approaches were used to evaluate the costs and benefits of prospective screening. First, the efficiency of HLA-B*5701 screening compared with no screening prior to abacavir initiation (intrinsic value of screening) was evaluated using a 60-day decision-tree model. Next, the practical value of screening was assessed using a lifetime discrete-event simulation model that compared HLA-B*5701 screening prior to abacavir use versus initiation with a tenofovir-containing regimen. Screening-effectiveness parameters were taken from an open-label trial that incorporated screening prior to abacavir initiation and other published studies. Treatment efficacy was derived from clinical trials. Modelling assumptions, costs ($US, year 2007 values) and other parameters were derived from published sources, primary data analysis and expert opinion. Multiple one-way sensitivity and scenario analyses were performed to assess parameter uncertainty. The primary outcome measure for the short-term screening versus no screening analysis was cost per patient. For the long-term analysis, outcomes were presented as QALYs. Costs and effects were discounted at 3% per year.. Over the first 60 days of treatment, prospective screening prior to abacavir initiation cost an additional $US17 per patient and avoided 537 HSRs per 10,000 patients. The per-patient cost of screening was sensitive to the cost of the genetic test, HSR costs and screening performance. In the lifetime model, screening-informed abacavir use was more effective and less costly than initiation with a tenofovir-containing regimen in the base case and in sensitivity analyses.. Our results suggest that prospective HLA-B*5701 screening prior to abacavir initiation produces cost savings and should become a standard component of HIV care.

Topics: Adenine; Adult; Anti-HIV Agents; Antiretroviral Therapy, Highly Active; Computer Simulation; Cost-Benefit Analysis; Decision Trees; Dideoxynucleosides; Drug Hypersensitivity; Drug-Related Side Effects and Adverse Reactions; Genetic Testing; HIV Infections; HLA-B Antigens; Humans; Middle Aged; Models, Economic; Organophosphonates; Quality-Adjusted Life Years; Tenofovir; United States

Adverse drug reactions (ADRs) have a major impact on patients, physicians, health care providers, regulatory agencies and pharmaceutical companies. Identifying the genetic contributions to ADR risk may lead to a better understanding of the underlying mechanisms, identification of patients at risk and a decrease in the number of events. Technological advances have made the routine monitoring and investigation of the genetic basis of ADRs during clinical trials possible. We demonstrate through simulation that genome-wide genotyping, coupled with the use of clinically matched or population controls, can yield sufficient statistical power to permit the identification of strong genetic predictors of ADR risk in a prospective manner with modest numbers of ADR cases. The results of a 500,000 single nucleotide polymorphism analysis of abacavir-associated hypersensitivity reaction suggest that the known HLA-B gene region could be identified with as few as 15 cases and 200 population controls in a sequential analysis.

Topics: Clinical Trials as Topic; Dideoxynucleosides; DNA; Drug Hypersensitivity; Drug-Related Side Effects and Adverse Reactions; Genome, Human; HLA-B Antigens; Humans; Pharmacogenetics; Polymorphism, Single Nucleotide

Topics: Anti-HIV Agents; Didanosine; Dideoxynucleosides; Drug-Related Side Effects and Adverse Reactions; Humans; Myocardial Ischemia; Risk Factors; United States; United States Food and Drug Administration

I was invited to comment on the article in this issue by Larry Lesko, "Personalized Medicine: Elusive Dream or Imminent Reality?",(1) especially with respect to three questions. There are several possible approaches to discussing these questions. One is to simply answer the question as directly and succinctly as possible; another is to expand on the questions. For the purpose of this Commentary, I try to do both.

Topics: Anti-HIV Agents; Biomedical Research; Dideoxynucleosides; Drug Industry; Drug-Related Side Effects and Adverse Reactions; Humans; Molecular Diagnostic Techniques; Pharmaceutical Preparations; Pharmacogenetics; Product Surveillance, Postmarketing; Prospective Studies; Randomized Controlled Trials as Topic

Topics: Alkynes; Anti-HIV Agents; Antibiotics, Antitubercular; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Antiviral Agents; Benzoxazines; Cyclopropanes; Dideoxynucleosides; Drug Monitoring; Drug Therapy; Drug-Related Side Effects and Adverse Reactions; Etidronic Acid; Humans; Infliximab; Leprostatic Agents; Osteitis Deformans; Oxazines; Rifampin; Risedronic Acid; Thalidomide; Thionucleotides; Trastuzumab