Severe abacavir hypersensitivity reaction in a patient tested HLA-B*5701 negative

Abacavir adverse reactions related with HLA-B*57: 01 haplotype in a large cohort of patients infected with HIV

OBJECTIVE

Carriage of human leukocyte antigen (HLA)-B*57:01 allele increases the risk of abacavir hypersensitivity reaction. Therefore, since 2008 HIV treatment guidelines recommend HLA-B*57:01 screening before abacavir administration, greatly reducing hypersensitivity reaction rate. However, clinically suspected abacavir-related hypersensitivity reactions are described in allele non-carriers. Major aim of this study was to evaluate the relationship between HLA-B*57:01 pattern and abacavir-related hypersensitivity reaction, focusing on hypersensitivity reaction prevalence in allele non-carriers.

METHODS

We included all outpatients aged >18 years old with HIV infection and known HLA-B*57:01 pattern, followed at our Department from January 2000 until December 2017. Patients were divided according to HLA-B*57:01 pattern and first antiretroviral treatment prescribed (containing or not abacavir) as follows: HLA-B*57:01 allele carriers treated with abacavir and HLA-B*57:01 allele non-carriers treated with abacavir. We considered all adverse events reported during first abacavir administration, differentiating between confirmed hypersensitivity reactions and non-hypersensitivity reactions, according to abacavir hypersensitivity reaction definition included in the abacavir EU Summary of Product Characteristics and the US Prescribing Information.

RESULTS

A total of 3144 patients had a known HLA-B*57:01 pattern. About 5.4% of them showed allele polymorphism; Caucasian ethnicity was the most represented. In this cohort, 1801 patients were treated with a first abacavir-containing regimen (98.2% of them was represented by allele non-carriers). 191 out of 1801 patients discontinued abacavir because of toxicity/intolerance; among them 107 described adverse events fulfilled the criteria of confirmed abacavir hypersensitivity reaction (22/32 allele-positive patients and 85/1769 allele-negative patients). After having experienced a confirmed abacavir hypersensitivity reaction, abacavir was re-administered to eight HLA-B*57:01 negative patients. Seven of them re-experienced a syndrome consistent with hypersensitivity reaction, finally leading to drug discontinuation. Overall, no fatal reactions were described.

CONCLUSION

Not all abacavir-related side effects occur as a result of classic HLA-B*57:01-mediated hypersensitivity reaction, as they can develop irrespective of HLA-B*57:01 status. Clinical vigilance must be an essential part of the management of individuals starting abacavir, at any time during treatment. In a 'real-life' setting, clinical diagnosis of suspected abacavir hypersensitivity reaction in allele non-carriers remains crucial for further clinical decision making.

Drug reaction with eosinophilia and systemic symptoms related to antiretroviral treatment in human immunodeficiency virus patients

BACKGROUND

The drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a life-threatening condition caused by different medications. The objective of this study was to analyze DRESS cases related to antiretroviral therapy in human immunodeficiency virus (HIV) patients.

MATERIALS AND METHODS

Systematic review of DRESS suspected cases in HIV patients associated to antiretrovirals published between January 1998 and April 2017. The registry of the severe cutaneous adverse reactions score was used to classify each report as a "definitive," "probable," "possible," or "no" DRESS case. Clinical characteristics, management, and outcomes were evaluated.

RESULTS

Thirty-five case reports were analyzed involving 5 antiretrovirals: Abacavir in 10 (28.6%) cases, efavirenz in 6 (17.1%), nevirapine in 12 (34.3%), raltegravir in 6 (17.1%), and tenofovir in 1 (2.9%). Mean age of the patients was 40 ± 13 years, 65% of which were male. A total of 57.1% reports were classified as having a "definitive-probable" DRESS case. Management was based on withdrawal of the causal antiretroviral and corticosteroids in 68.6% of the cases. None of the patients died. Treatment with nevirapine or raltegravir, the longer onset of symptoms and the presence of lymphadenopathy, eosinophilia, liver involvement, and a longer time for clinical resolution were more frequent among "definitive-probable" DRESS cases.

CONCLUSIONS

A DRESS syndrome has to be suspected in HIV patients with lymphadenopathy, eosinophilia, and liver involvement developing weeks after the initiation of nevirapine or raltegravir. Suspension of the causal antiretroviral and in most cases treatment with corticosteroids allowed adequate clinical control.

HLA-B*57:01 allele prevalence in HIV-infected North American subjects and the impact of allele testing on the incidence of abacavir-associated hypersensitivity reaction in HLA-B*57:01-negative subjects

Background

The presence of the HLA-B*57:01 allele in HIV-infected subjects is associated with a higher risk of abacavir-associated hypersensitivity reaction (ABC HSR). HLA-B*57:01 allele prevalence varies in different populations, but HLA-B*57:01 testing with immunological confirmation has had a negative predictive value for ABC HSR between 97 and 100%.

Methods

In the ASSURE study (EPZ113734), the HLA-B*57:01 prevalence in virologically suppressed, antiretroviral treatment–experienced, HIV-infected subjects from the United States, including Puerto Rico, was assessed.

Results

Three hundred eighty-five subjects were screened; 13 were HLA-B*57:01 positive and 372 were negative. Only HLA-B*57:01-negative, abacavir-naive subjects were eligible to enroll into the ASSURE trial. Eleven of the 13 subjects who possessed the HLA-B*57:01 allele were white, the other 2 were African-American. There was no geographic clustering of HLA-B*57:01-positive subjects, and the incidence correlated roughly with those states with the greatest numbers of subjects screened. Similarly, there was no statistically significant correlation between subjects who possessed or lacked the allele and age, gender, ethnicity or CD4+ T-cell numbers. The incidence of ABC HSR following abacavir initiation was also evaluated. Only 1 of 199 HLA-B*57:01-negative subjects (an African-American male) randomized to receive abacavir-containing treatment developed symptoms consistent with suspected ABC HSR; ABC HSR was not immunologically confirmed.

Conclusions

These findings confirm the utility of HLA-B*57:01 allele testing to reduce the frequency of ABC HSR. The prevalence of HLA-B*57:01 positivity was higher in white than in African-American subjects. In HLA-B*57:01-negative subjects, suspected ABC HSR is very rare, but should lead to discontinuation of abacavir when ABC HSR cannot be definitively excluded from the differential diagnosis.

Trial registration

The ASSURE (EPZ113734) study was registered on ClinicalTrials.gov registration on April 8th 2010 and the registration number is NCT01102972.

HLADR: a database system for enhancing the discovery of biomarkers for predicting human leukocyte antigen-mediated idiosyncratic adverse drug reactions

Aim: To establish a database for the associations between idiosyncratic drug reactions (IDRs) and human leukocyte antigens (HLAs) and to systematically assess the characteristics of the drug–HLA associations. Materials & methods: Electronic databases were searched to extensively identify drug–HLA association studies from 1966 to present. Results: A drug-HLA-IDR database, HLADR, was created. The drug–HLA relationship network clearly reflected an ethnicity dependency of the associations. The positive predictive values and the negative predictive values demonstrated that other potential factors may also regulate the occurrence of HLA-specific IDRs. Conclusions: Constructing studies with samples from homogeneous ethnic groups and identifying cofactors that affect negative predictive values and positive predictive values will become necessary to enhance the predictability of HLA biomarkers for future research on IDRs.

Extensive pulmonary involvement with raltegravir-induced DRESS syndrome in a postpartum woman with HIV

An 18-year-old postpartum woman with HIV, on lamivudine-zidovudine, lopinavir-ritonavir and raltegravir, presented with a 1-week history of rash and fevers. Initially admitted to obstetrics and gynaecology service for treatment of possible endometritis, she was transferred to the HIV medicine service for high fever, respiratory distress, hypotension and tachycardia. On admission, she was febrile (102°F) with findings of cervical and submandibular lymphadenopathy, diffuse morbilliform rash, generalised pruritus, facial oedema, and oedematous hands and feet. Consultations to various specialty services were initiated to rule out infectious, dermatological, rheumatological and drug-induced aetiologies. On the fourth day of hospitalisation, laboratory findings of significant eosinophilia and hepatitis (alanine aminotransferase 147 IU/L and aspartate aminotransferase 124 IU/L), in conjunction with the identification of the timing of medication use, led to a diagnosis of DRESS (drug reaction with eosinophilia and systemic symptoms) syndrome secondary to raltegravir. After discontinuing raltegravir and starting prednisone, her DRESS symptoms completely resolved.

The DRESS syndrome: a literature review

The Drug Reaction with Eosinophilia and Systemic Symptom (DRESS) is a severe adverse drug-induced reaction. Diagnosing DRESS is challenging due to the diversity of cutaneous eruption and organs involved. We used the RegiSCAR scoring system that grades DRESS cases as "no," "possible," "probable," or "definite" to classify cases reported in the literature. We also analyzed the clinical course and treatments of the cases. A total of 44 drugs were associated with the 172 cases reported between January 1997 and May 2009 in PubMed and MEDLINE. The most frequently reported drug was carbamazepine, and the vast majority of cases were classified as "probable/definite" DRESS cases. Hypereosinophilia, liver involvement, fever, and lymphadenopathy were significantly associated with "probable/definite" DRESS cases, whereas skin rash was described in almost all of the cases, including "possible cases." Culprit drug withdrawal and corticosteroids constituted the mainstay of DRESS treatment. The outcome was death in 9 cases. However, no predictive factors for serious cases were found. This better knowledge of DRESS may contribute to improve the diagnosis and management of this syndrome in clinical practice.

Hypersensitivity reactions to HIV therapy

Many drugs used for the treatment of HIV disease (including the associated opportunistic infections) can cause drug hypersensitivity reactions, which vary in severity, clinical manifestations and frequency. These reactions are not only seen with the older compounds, but also with the newer more recently introduced drugs. The pathogenesis is unclear in most cases, but there is increasing evidence to support that many of these are mediated through a combination of immunologic and genetic factors through the major histocompatibility complex (MHC). Genetic predisposition to the occurrence of these allergic reactions has been shown for some of the drugs, notably abacavir hypersensitivity which is strongly associated with the class I MHC allele, HLA-B*5701. Testing before the prescription of abacavir has been shown to be of clinical utility, has resulted in a change in the drug label, is now recommended in clinical guidelines and is practiced in most Western countries. For most other drugs, however, there are no good methods of prevention, and clinical monitoring with appropriate (usually supportive and symptomatic) treatment is required. There is a need to undertake further research in this area to increase our understanding of the mechanisms, which may lead to better preventive strategies through the development of predictive genetic biomarkers or through guiding the design of drugs less likely to cause these types of adverse drug reactions.

Management of HIV infection in treatment-naive patients: a review of the most current recommendations

PURPOSE

The most current guidelines issued by the Department of Health and Human Services (DHHS) on the management of human immunodeficiency virus (HIV) infection in treatment-naive patients are reviewed.

SUMMARY

Treatment guidelines are updated frequently because of the emergence of data demonstrating the risks and benefits of antiretroviral therapy. The DHHS guidelines strongly recommend initiating therapy in patients with certain conditions regardless of CD4 cell count and in patients with CD4 cell counts of <350 cells/mm(3). Although supporting data are less definitive, treatment is also recommended for patients with CD4 cell counts of 350-500 cells/mm(3). Treatment for patients with CD4 cell counts of >500 cells/mm(3) is controversial. Although cumulative observational data and biological evidence support treatment at higher CD4 cell counts, randomized controlled trial data to support this are not available, and the risk of antiretroviral toxicities, resistance, non-adherence, and cost should be considered in individual patients. The preferred regimens have been consolidated to four options, including a dual-nucleoside reverse transcriptase inhibitor backbone (tenofovir plus emtricitabine) with a nonnucleoside reverse transcriptase inhibitor (efavirenz), a ritonavir-boosted protease inhibitor (atazanavir plus ritonavir or darunavir plus ritonavir), or an integrase strand-transfer inhibitor (raltegravir). Regimens are classified as alternative or acceptable when they have potential safety or efficacy concerns, have higher pill burdens, or require more-frequent administration compared with preferred regimens.

CONCLUSION

The DHHS 2011 guidelines advocate earlier antiretroviral therapy initiation than recommended in recent years, and preferred regimens have been refined to maximize efficacy, safety, and quality of life for treatment-naive HIV-infected patients.

Successful translation of pharmacogenetics into the clinic: the abacavir example

Abacavir hypersensitivity syndrome (AHS) is a potentially life-threatening illness occurring in 4-8% of those initiating the drug. Early studies identified a strong association between the MHC class I allele HLA-B*5701 and AHS. These studies suggested that HLA-B*5701 holds promise as a screening test to prevent AHS, but concern arose from HLA-B*5701-negative cases with a clinical diagnosis of AHS, and particularly from early reports of apparently low sensitivities of HLA-B*5701 for AHS in patients of non-White race. However, open screening studies suggested that HLA-B*5701 screening can largely eliminate AHS. Furthermore, skin-patch testing was used in later-generation studies to separate those patients with true immunologically mediated AHS from those with false-positive clinical diagnoses. Currently, high-level evidence suggests that HLA-B*5701 has a negative predictive value of 100% for patch-test-confirmed AHS, which is generalizable across White and Black populations. Current HIV treatment guidelines have been revised to reflect the recommendation that HLA-B*5701 screening be incorporated into routine care for patients who may require abacavir. New laboratory techniques such as PCR and flow cytometric methods, as well as an international quality assurance program, have evolved to ensure the availability of cost-effective screening methods whose consistency and standard can be maintained over time. An elegant body of basic science has evolved, which supports and complements the clinical research in suggesting that AHS is specifically and exquisitely restricted by HLA-B*5701 and mediated by CD8+ lymphocytes. Abrogating factors explaining why 45% of those carrying HLA-B*5701 can tolerate abacavir remain to be defined. The research approach applied to AHS has led to a genetic screening test being successfully implemented globally in primary HIV clinical practice. The abacavir 'example' can be applied to other drugs to facilitate the development and operationalization of genetic tests that may be useful to predict and prevent otherwise unpredictable drug reactions.

Personalizing antiretroviral therapy: is it a reality?

The concept of personalizing antiretroviral therapy is not novel, since the complexity of the HIV patient and their therapy has always demanded consideration of the patient's 'pharmacoecology', taking into account factors such as adherence, drug-drug and food-drug interactions, underlying disease and host states, such as organ dysfunction and pregnancy. Recent advances in science have taken this one step further with the technology now available to use both a candidate and whole-genome approach to explore the genetics of host-virus interactions, as well as the pharmacogenetics of the toxicity and efficacy of antiretroviral therapy. The genetics of host-virus interactions have improved our understanding of the pathogenesis of HIV which will aid in the research and development of an HIV vaccine. Most published HIV pharmacogenetic studies have utilized a candidate gene approach. Although these types of studies have provided insight into the pathogenesis and pharmacogenetics of drug disposition, drug interactions, drug efficacy and toxicity and host-virus interactions, very few will lend themselves to a widespread clinical application. The application of HLA-B*5701 screening to prevent abacavir hypersensitivity acts as an important example of the successful widespread implementation of a pharmacogenetic test into the clinic and defines the key steps necessary for the clinical application of pharmacogenetic tests in general.

Abacavir-induced reaction with fever and severe skin rash in a patient tested human leukocyte antigen-B*5701 negative

The most serious adverse event caused by abacavir is the hypersensitivity reaction, which is usually associated with the presence of the human leukocyte antigen (HLA) subtype B*5701, as shown in recent studies. We describe the case of a 41-year-old Caucasian female patient, who tested HLA-B*5701 negative and developed fever and severe skin rash 10 weeks after the start of abacavir therapy. Similar reports suggest that not all severe abacavir-induced adverse events occur as a result of classic hypersensitivity reactions, and can present also in HLA-B*5701-negative patients.

[HLA-B*5701 and abacavir hypersensitivity reaction]

A potentially life-threatening hypersensitive reaction occurs in association with initiation of HIV nucleoside analogue abacavir therapy in 4 to 8% of patients. Preliminary studies appear to confirm the role of the immune system in abacavir hypersensitivity. The reaction is possibly the result of presentation of drug peptides onto HLA, that may induce a pathogenic T-cell response. Hypersensitivity reaction to abacavir is strongly associated with the presence of the HLA-B*5701 allele and prospective HLA-B*5701 genetic screening has now been instituted in clinical practice to reduce the risk of hypersensitivity reaction.

Current trends in screening across ethnicities for hypersensitivity to abacavir

Abacavir is a potent nucleoside analog reverse transcriptase inhibitor approved for the treatment of HIV infection. Approximately 5-8% of Caucasian patients receiving abacavir develop a hypersensitivity reaction, characterized by rash, fever and, occasionally, multisystemic involvement. Rechallenge with the drug can be fatal. The discovery of the mechanisms involved in this hypersensitivity reaction and the identification of tools for its prediction are the subject of this review. The most relevant finding is the recognition of a strong association between one specific haplotype at the HLA complex type I, HLA-B*5701, and the abacavir hypersensitivity reaction. The heterogeneity in the prevalence of HLA-B*5701 across distinct ethnicities accounts for differences in the risk of abacavir hypersensitivity reactions in distinct populations.

Abacavir/lamivudine fixed dose combination in the treatment of patients with HIV infection

HIV infection remains a common cause of morbidity and mortality worldwide. Fortunately, patients treated with combination antiretroviral therapy (ART) have significantly improved survival rates and quality of life. The standard of care for the treatment of ART-naive patients includes three drugs, two of which should be nucleoside reverse transcriptase inhibitors (NRTIs). Abacavir/lamivudine (ABC/3TC) is a fixed dose combination NRTI tablet that has been approved as an NRTI backbone. ABC/3TC is among the NRTI combinations that are recommended as first line in the most recent International AIDS Society–USA guidelines and WHO European Region protocol. However, owing to recently published data raising the possibility of an association between abacavir and heart disease, as well as data regarding efficacy in patients with higher HIV RNA levels, ABC/3TC has now been listed as an alternative NRTI backbone in the latest USA Department of Health and Human Services guidelines. While ABC has been associated with a hypersensitivity reaction that may be severe, a new test has been demonstrated to be effective in screening for the gene that is associated with this reaction.