Pharmacogenomic evaluation of single nucleotide polymorphisms associated with oxaliplatin-induced peripheral neuropathy: a preliminary study

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Atazanavir-induced severe episodes of kidney stones in an HIV-1-infected subject characterized by a CYP3A poor metabolizer phenotype

Background: Atazanavir, an antiretroviral drug of the protease inhibitor class, is coadministered with ritonavir to inhibit atazanavir metabolism and decrease pharmacokinetic variability. Atazanavir is metabolised mainly by CYP3A4/5 enzymes. High CYP3A intersubject variability has been documented in most cases on a genetic basis. The CYP3A5*3 allele affects splicing defect and protein truncation. Recently a new intronic variant, CYP3A4*22, was found associated with reduced CYP3A4 activity. To assess whether an altered CYP3A activity impairs the metabolism of atazanavir, we investigated the two functional polymorphisms. To the best of our knowledge, this is the first case report showing that overexposure to ATV is associated with CYP3A poor phenotype and nephrolithiasis. Further study is needed in order to confirm this interesting observation. Case Presentation: We describe the case of a 43 year-old HIV-1-infected man treated with atazanavir/ritonavir plus lamivudine who experienced early and recurrent severe episodes of kidney stones. Atazanavir plasma trough concentrations showed a value higher than the normal range, thus we investigated the two polymorphisms that are known to affect CYP3A4/5 activity. This analysis revealed that our patient was a CYP3A poor metabolizer since he carried CYP3A4*1/*22 and CYP3A5*3/*3 genotypes. Conclusion: We suggest that screening of CYP3A functional variants is an appropriate approach, helping in treatment choice and potential dosage adjustment of protease inhibitors

Ethnic differences in frequencies of gene polymorphisms in the MYCL1 region and modulation of lung cancer patients' survival

Linkage disequilibrium (LD) analysis to refine a region associated with lung cancer progression on chromosome 1p34 identified a 106 kb LD block that includes MYCL1, TRIT1 (tRNA isopentenyltransferase 1) and MFSD2 (major facilitator superfamily domain-containing 2). Case-only association study on SNPs mapping in TRIT1 and MFSD2 indicated that the rare Leu allele (frequency: 0.04) of the TRIT1 Phe202Leu variation predicts short survival as compared to the common Phe/Phe genotype (hazard ratio (HR)=1.7; 95% CI, 1.03-2.86; P=0.039) in 335 Italian lung adenocarcinoma samples. A replication study in an independent population of 246 Norwegian lung cancer patients confirmed the significant association of the Phe202Leu polymorphism with patients' survival, but the rare allele was associated with better survival rate (HR=0.5; 95% CI, 0.26-0.91; P=0.023). The rare allele of TRIT1 Phe202Leu SNP was approximately seven-fold more frequent in Asian than in Caucasian subjects and three additional SNPs in the TRIT1 and MFSD2 genes showed ethnic differences in allelic frequencies. These results suggest that polymorphisms in the MYCL1 LD region affect lung cancer survival but that the functional element(s) may show population-specific patterns

Clinical and genetic determinants of nevirapine plasma trough concentration

Background: Only few data are available on the influence of CYP2B6 and CYP3A4/A5 polymorphisms on nevirapine plasma concentrations in the Caucasian population. Our aim was to assess the impact of CYP2B6 and CYP3A4/A5 polymorphisms on nevirapine plasma concentrations consecutively collected. Methods: We retrospectively analyzed clinical data of all HIV-positive patients who were followed at the Infectious Diseases Unit, DIBIC Luigi Sacco, University of Milan between January 2000 and December 2015. All patients with at least one nevirapine plasma trough concentration (NVP Cmin) determination were tested for CYP2B6 c.516 G>T, CYP3A4*22C>T and CYP3A5*3 A>G polymorphisms. Univariate and multivariate regression analyses were carried out considering NVP Cmin as the dependent variable and genetic polymorphisms and clinical characteristics as independent variables. Results: A total of 143 patients were evaluated. Most of them were males (61.5%) and Caucasian (92.3%). Overall, NVP Cmin varied from 1571 to 14,189\u2009 ng/mL (median\u2009 =\u2009 5063\u2009 ng/mL, interquartile range\u2009 =\u2009 3915\u20136854). The median NVP Cmin significantly differed in patients with different CYP2B6 genotypes, but did not vary in those with different CYP3A phenotypes. In the final general linear model, factors significantly associated with a higher NVP Cmin were each extra unit of T alleles of CYP2B6 rs3745274 (\u3b2\u2009 =\u2009 0.328, 95% confidence interval\u2009 =\u2009 0.172\u20130.484; p\u2009 <\u2009 0.0001), older age (\u3b2\u2009 =\u2009 0.362, 95% confidence interval\u2009 =\u2009 0.193\u20130.532; p\u2009 <\u2009 0.0001) and hepatitis C virus coinfection (\u3b2\u2009 =\u2009 0.161, 95% confidence interval\u2009 =\u2009 0.006\u20130.315; p\u2009 <\u2009 0.041). Conclusion: Our study, conducted in a prevalent Caucasian population, highlighted the importance of CYP2B6 genetic variants in influencing nevirapine plasma trough concentration. Furthermore, older age and hepatitis C virus coinfection significantly increase exposure to nevirapine

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

BackgroundNevirapine 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.MethodsWe 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 (2) test. A multivariable logistic regression model was constructed using a backward elimination method.ResultsThree 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 (58IU/L vs 26IU/L; p=0.041) and ALT (82IU/L vs 27IU/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.ConclusionsAccording 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

Undetected toxicity risk in pharmacogenetic testing for dihydropyrimidine dehydrogenase

Fluoropyrimidines, the mainstay agents for the treatment of colorectal cancer, alone or as a part of combination therapies, cause severe adverse reactions in about 10%-30% of patients. Dihydropyrimidine dehydrogenase (DPD), a key enzyme in the catabolism of 5-fluorouracil, has been intensively investigated in relation to fluoropyrimidine toxicity, and several DPD gene (DPYD) polymorphisms are associated with decreased enzyme activity and increased risk of fluoropyrimidine-related toxicity. In patients carrying non-functional DPYD variants (c.1905+1G>A, c.1679T>G, c.2846A>T), fluoropyrimidines should be avoided or reduced according to the patients' homozygous or heterozygous status, respectively. For other common DPYD variants (c.496A>G, c.1129-5923C>G, c.1896T>C), conflicting data are reported and their use in clinical practice still needs to be validated. The high frequency of DPYD polymorphism and the lack of large prospective trials may explain differences in studies' results. The epigenetic regulation of DPD expression has been recently investigated to explain the variable activity of the enzyme. DPYD promoter methylation and its regulation by microRNAs may affect the toxicity risk of fluoropyrimidines. The studies we reviewed indicate that pharmacogenetic testing is promising to direct personalised dosing of fluoropyrimidines, although further investigations are needed to establish the role of DPD in severe toxicity in patients treated for colorectal cancer

A comprehensive appraisal of laboratory biochemistry tests as major predictors of COVID-19 severity

Context: A relevant portion of COVID-19 patients develop severe disease with negative outcomes. Several biomarkers have been proposed to predict COVID-19 severity, but no definite interpretative criteria have been established to date for stratifying risk. Objective: To evaluate six serum biomarkers (C-reactive protein, lactate dehydrogenase, Ddimer, albumin, ferritin and cardiac troponin T) for predicting COVID-19 severity and to define related cut-offs able to aid clinicians in risk stratification of hospitalized patients. Design: A retrospective study of 427 COVID-19 patients was performed. Patients were divided into groups based on their clinical outcome: non-survivors vs. survivors and patients admitted to intensive care unit vs. others. ROC curves and likelihood ratios were employed to define predictive cut-offs for evaluated markers. Results: Marker concentrations at peak were significantly different between groups for both selected outcomes. At univariate logistic regression analysis, all parameters were significantly associated with higher odds of death and intensive care. At the multivariate analysis, high concentrations of lactate dehydrogenase and low concentrations of albumin in serum remained significantly associated with higher odds of death, while only low lactate dehydrogenase activities remained associated with lower odds of intensive care admission. The best cut-offs for death prediction were &gt;731 U/L for lactate dehydrogenase and 6418 g/L for albumin, while a lactate dehydrogenase activity &lt;425 U/L was associated with a negative likelihood ratio of 0.10 for intensive treatment. Conclusions: Our study identifies which biochemistry tests represent major predictors of COVID-19 severity and defines the best cut-offs for their use