A pharmacogenetics study in Mozambican patients treated with nevirapine: full resequencing of TRAF3IP2 gene shows a novel association with SJS/TEN susceptibility

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.

Review on Databases and Bioinformatic Approaches on Pharmacogenomics of Adverse Drug Reactions

Pharmacogenomics has been used effectively in studying adverse drug reactions by determining the person-specific genetic factors associated with individual response to a drug. Current approaches have revealed the significant importance of sequencing technologies and sequence analysis strategies for interpreting the contribution of genetic variation in developing adverse reactions. Advance in next generation sequencing and platform brings new opportunities in validating the genetic candidates in certain reactions, and could be used to develop the preemptive tests to predict the outcome of the variation in a personal response to a drug. With the highly accumulated available data recently, the in silico approach with data analysis and modeling plays as other important alternatives which significantly support the final decisions in the transformation from research to clinical applications such as diagnosis and treatments for various types of adverse responses.

A multivariate genetic analysis confirms rs5010528 in the human leucocyte antigen-C locus as a significant contributor to Stevens-Johnson syndrome/toxic epidermal necrolysis susceptibility in a Mozambique HIV population treated with nevirapine

Objectives

Nevirapine is used in developing countries for the treatment of HIV infection, but its use is associated with rare serious adverse reactions such as Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). Recently, an association between rs5010528 in the human leucocyte antigen (HLA)-C locus and SJS/TEN susceptibility has been described in sub-Saharan populations. Our aim was to verify this association in a population of nevirapine-treated patients from Mozambique.

Methods

The rs5010528 SNP was analysed by direct sequencing in 27 patients who had developed SJS/TEN and 75 patients who did not develop adverse reactions after nevirapine treatment. A case-control association study was conducted. A multivariate analysis was performed in order to evaluate the role of HLA-C also in relation to other susceptibility genetic factors (CYP2B6, TRAF3IP2, HCP5, PSORS1C1 and GSTM1 genes).

Results

rs5010528 was significantly associated with a higher risk of developing SJS/TEN; the variant allele was more frequent in cases than in controls, conferring a high risk of developing this adverse reaction in carriers (OR = 5.72 and P = 0.0002 at genotype level, OR = 3.51 and P = 0.0002 at allelic level). The multivariate analysis showed that the HLA-C SNP, CYP2B6 (rs28399499), TRAF3IP2 (rs76228616) and GSTM1 (null genotype) can explain 25% of the susceptibility to this reaction, with the HLA-C SNP as the most significant contributor (P = 0.02 and OR = 5.64).

Conclusions

Our study confirmed the association of the rs5010528 SNP in the HLA-C region with susceptibility to developing SJS/TEN in a population from Mozambique, suggesting that it could be a good genomic biomarker for SJS/TEN susceptibility in different sub-Saharan populations.

Impact of glutathione transferases genes polymorphisms in nevirapine adverse reactions: a possible role for GSTM1 in SJS/TEN susceptibility

PURPOSE

Nevirapine (NVP) is used in developing countries as first-line treatment of HIV infection. Unfortunately, its use is associated with common serious adverse drug reactions, such as liver toxicity and the most severe and rare Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). GSTT1 and GSTM1 genes code for enzymes involved in the metabolism of a wide range of drugs. We hypothesized that this gene variability could be implicated in NVP adverse reactions.

METHODS

We analyzed the GSTM1 and GSTT1 null genotypes by multiplex PCR in a population of 181 patients from Mozambique, treated with NVP. A case/control association study was performed. We also counted the number of risk alleles in SJS/TEN patients and in controls, including the GSTM1 null genotype and four previously identified risk alleles in CYP2B6, HCP5, and TRAF3IP2 genes.

RESULTS

Among patients, 27 had developed SJS/TEN and 76 had developed hepatotoxicity during the treatment. The GSTM1 null genotype was more frequent in the cases with SJS/TEN than in the controls (OR = 2.94, P = 0.027). This association is also observed when other risk factors are taken into account, by a multivariate analysis (P = 0.024 and OR = 3.58). The risk allele counting analysis revealed a significantly higher risk for SJS/TEN in patients carrying three or four risk alleles. Moreover, all subjects with five or six risk alleles developed SJS/TEN, while subjects without any risk alleles were present only in the control group.

CONCLUSIONS

We observed an association between GSTM1 and SJS/TEN susceptibility. Moreover, GSTM1 contributes to the definition of a genetic risk profile for SJS/TEN susceptibility.

Stevens-Johnson syndrome and toxic epidermal necrolysis: an update on pharmacogenetics studies in drug-induced severe skin reaction

Stevens-Johnson syndrome and toxic epidermal necrolysis are severe, life-threatening drug reactions involving skin and membranes mucous, which are associated with significant morbidity and mortality and triggered, especially by drug exposure. Different studies have demonstrated that drug response is a multifactorial character and that the interindividual variability in this response depends on both environmental and genetic factors. The last ones have a relevant significance. In fact, the identification of new specific genetic markers involved in the response to drugs, will be of great utility to establish a more personalized therapeutic approach and to prevent the appearance of these adverse reactions. In this review, we summarize recent progresses in the Pharmacogenetics studies related to Stevens-Johnson syndrome/toxic epidermal necrolysis reporting the major genetic factors identified in the last years as associated with the disease and highlighting the use of some of these genomic variants in the clinical practice.