Cómo estimar la composición corporal en la enfermedad de Huntington. Estudio transversal y observacional con bioimpedancia de múltiples frecuencias / How to estimate body composition in Huntington’s disease. A cross-sectional, observational study using multiple frequencies bioimpedance

Introducción La enfermedad de Huntington (EH) es un trastorno raro neurodegenerativo. La información fiable del estado nutricional, especialmente de la composición corporal, es crítica en clínica y en investigación. La facilidad de aplicación y portabilidad del análisis de la bioimpedancia de múltiples frecuencias (mfBIA) la convierten en una herramienta atractiva para medirla, pero se desconoce su precisión en la EH. Objetivo Evaluar la precisión del mfBIA frente a la absorciometría dual de rayos X (DEXA) en la EH. Pacientes y métodos Estudio transversal, observacional y unicéntrico. La EH se midió con la subescala motora de la escala unificada de valoración de la EH y con la capacidad funcional total. La composición corporal se valoró según la masa libre de grasa (MLG), la masa grasa (MG), el índice de masa libre de grasa (IMLG) y el índice de masa grasa (IMG). Se utilizó el coeficiente de correlación intraclase con intervalos de confianza al 95% y estimaciones de sesgo mediante gráficos de Bland-Altman. Resultados Se incluyó a 16 pacientes, siete hombres y nueve mujeres, con edad media de 58,5 (32-68) años, capacidad funcional total de 10 (3-13) y escala unificada de valoración de la EH de 31 (7-85). La fiabilidad era alta entre el mfBIA y la DEXA para el IMLG en hombres, 0,88 (intervalo de confianza al 95%: 0,17-0,98), y mujeres, 0,9 (intervalo de confianza al 95%: 0,61-0,98); y para el IMG en hombres, 0,97 (intervalo de confianza al 95%: 0,83-0,99), y mujeres, 0,91 (intervalo de confianza al 95%: 0,68-0,98). El mfBIA sobreestimó ligeramente la MLG, la MG, el IMG y el IMLG en los hombres, pero subestimó el IMLG en las mujeres. Conclusiones El mfBIA es un método fácil de usar, seguro, no invasivo y preciso para medir la composición corporal y el estado nutricional en pacientes con EH leve-moderada. (AU)

INTRODUCTION Huntington´s disease (HD) is a rare neurodegenerative disorder. Reliable information about nutritional status, especially body composition from individuals with HD is critical for clinical care and research. The ease of application and portability of multiple frequencies bioelectrical impedance analysis (mfBIA) make it an attractive tool for measuring body composition, but its accuracy in HD is unknown. AIM To evaluate the accuracy of mfBIA vs. Dual X-ray absorptiometry (DEXA) in HD. PATIENTS AND METHODS Cross-sectional, observational, and single-center study. HD severity was measured using motor subscale of the unified Huntington´s disease rating scale (m-UHDRS) and the total functional capacity (TFC). Body composition was measured in terms of fat-free mass (FFM), fat mass (FM), fat-free mass index (FFMI), and fat mass index (FMI). Using Bland-Altman plots, we analyzed reliability between DEXA and mfBIA using the Intraclass Correlation Coefficient with 95% confidence intervals (CI) and bias estimates for all. RESULTS We included 16 patients with HD, 7 men, and 9 women, median age of 58.5 (32;68) years, TFC: 10 (3;13), and m-UHDRS: 31 (7;85). The reliability between mfBIA and DEXA were high for FFMI in men: 0.88 (95% CI 0.17-0.98), and women: 0.90 (95% CI 0.61- 0.98); for FMI, men: 0.97 (95% CI 0.83-0.99), and women: 0.91 (95% CI 0.68-0.98). Compared to DEXA, mfBIA slightly overestimated FFM, FM, FMI and FFMI in men and underestimated FFMI in women. CONCLUSIONS mfBIA is an easy-to-use, safe, non-invasive, accurate method for measuring body composition and nutritional status in patients with mild-moderate HD. (AU)

Impact of CYP2D6 and CYP2B6 phenotypes on the response to tramadol in patients with acute post-surgical pain.

Tramadol is an important minor opioid prescribed for pain management. In this study, we analyzed the well-known impact of CYP2D6 genetic variation and 60 additional variants in eight candidate genes (i.e., ABCG2, SLCO1B1, CYP2D6, CYP2B6, CYP2C19, CYP2C9, CYP3A5, and CYP3A4) on tramadol efficacy and safety. Some 108 patients with pain after surgery admitted to a post-anesthesia care unit (PACU) and prescribed tramadol were recruited. They were genotyped, and tramadol M1/M2 metabolite concentrations were determined by a newly validated HPLC-MS/MS method. CYP2D6 intermediate (IM) and poor (PM) metabolizers showed lower M1 concentrations adjusted for dose/weight at 30 and 120 min compared to ultrarapid (UM) and normal (NM) metabolizers (univariate p < 0.001 and 0.020, multivariate p < 0.001 and 0.001, unstandardized ß coefficients = 0.386 and 0.346, R2 = 0.146 and 0.120, respectively). CYP2B6 PMs (n = 10) were significantly related to a higher reduction in pain 30 min after tramadol intake (univariate p = 0.038, multivariate p = 0.016, unstandardized ß coefficient = 0.224, R2 = 0.178), to lower PACU admission time (p = 0.007), and to lower incidence of adverse drug reactions (p = 0.038) compared to the other phenotypes. CYP3A4 IMs and PMs showed a higher prevalence of drowsiness and dizziness (p = 0.028 and 0.005, respectively). Our results suggest that the interaction of CYP2B6 and CYP2D6 phenotypes may be clinically relevant, pending validation of these results in large, independent cohorts. Additional research is required to clarify the impact of CYP3A4 genetic variation on tramadol response.

Identification of clinical and pharmacogenetic factors influencing metformin response in Type 2 diabetes mellitus.

Metformin, a hypoglycemic drug for Type 2 diabetes mellitus, shows variability in pharmacokinetics and response due to membrane transporters. This study followed 34 Type 2 diabetes mellitus patients on metformin treatment. Genetic variants in 11 metformin transport-related genes were analyzed, revealing associations. Specifically, SLC47A1 rs2289669 A/A and SLC22A4 rs1050152 T/T genotypes correlated with glycated hemoglobin values at 6 months. SLC47A1 rs2289669 G/A genotype influenced glucose levels at 6 months, while SLC29A4 rs3889348 A/A, SLC47A1 rs2289669 A/A, SLC22A4 rs1050152 C/T and SLC47A2 rs12943590 A/A genotypes were linked to glucose levels at 12 months. Additionally, ABCB1 rs2032582 C/A and ABCG2 rs2231137 C/T genotypes impacted cholesterol levels at 12 months. These findings shed light on metformin response determinants, offering insights for further research.

Bortezomib Pharmacogenetic Biomarkers for the Treatment of Multiple Myeloma: Review and Future Perspectives.

Multiple myeloma (MM) is a hematological neoplasm for which different chemotherapy treatments are used with several drugs in combination. One of the most frequently used drugs for the treatment of MM is the proteasome inhibitor bortezomib. Patients treated with bortezomib are at increased risk for thrombocytopenia, neutropenia, gastrointestinal toxicities, peripheral neuropathy, infection, and fatigue. This drug is almost entirely metabolized by cytochrome CYP450 isoenzymes and transported by the efflux pump P-glycoprotein. Genes encoding both enzymes and transporters involved in the bortezomib pharmacokinetic pathway are highly polymorphic. The response to bortezomib and the incidence of adverse drug reactions (ADRs) vary among patients, which could be due to interindividual variations in these possible pharmacogenetic biomarkers. In this review, we compiled all pharmacogenetic information relevant to the treatment of MM with bortezomib. In addition, we discuss possible future perspectives and the analysis of potential pharmacogenetic markers that could influence the incidence of ADR and the toxicity of bortezomib. It would be a milestone in the field of targeted therapy for MM to relate potential biomarkers to the various effects of bortezomib on patients.

Pharmacogenetics in the Treatment of Huntington's Disease: Review and Future Perspectives.

Huntington's disease (HD) is an autosomal dominant progressive brain disorder, caused by a pathological expansion of a CAG repeat that encodes the huntingtin gene. This genetic neurodegenerative rare disease is characterized by cognitive, motor, and neuropsychiatric manifestations. The aim of the treatment is symptomatic and addresses the hyperkinetic disorders (chorea, dystonia, myoclonus, tics, etc.) and the behavioural and cognitive disturbances (depression, anxiety, psychosis, etc.) associated with the disease. HD is still a complex condition in need of innovative and efficient treatment. The long-term goal of pharmacogenetic studies is to use genotype data to predict the effective treatment response to a specific drug and, in turn, prevent potential undesirable effects of its administration. Chorea, depression, and psychotic symptoms have a substantial impact on HD patients' quality of life and could be better controlled with the help of pharmacogenetic knowledge. We aimed to carry out a review of the available publications and evidence related to the pharmacogenetics of HD, with the objective of compiling all information that may be useful in optimizing drug administration. The impact of pharmacogenetic information on the response to antidepressants and antipsychotics is well documented in psychiatric patients, but this approach has not been investigated in HD patients. Future research should address several issues to ensure that pharmacogenetic clinical use is appropriately supported, feasible, and applicable.

Identification of Transporter Polymorphisms Influencing Metformin Pharmacokinetics in Healthy Volunteers.

For patients with type 2 diabetes, metformin is the most often recommended drug. However, there are substantial individual differences in the pharmacological response to metformin. To investigate the effect of transporter polymorphisms on metformin pharmacokinetics in an environment free of confounding variables, we conducted our study on healthy participants. This is the first investigation to consider demographic characteristics alongside all transporters involved in metformin distribution. Pharmacokinetic parameters of metformin were found to be affected by age, sex, ethnicity, and several polymorphisms. Age and SLC22A4 and SLC47A2 polymorphisms affected the area under the concentration-time curve (AUC). However, after adjusting for dose-to-weight ratio (dW), sex, age, and ethnicity, along with SLC22A3 and SLC22A4, influenced AUC. The maximum concentration was affected by age and SLC22A1, but after adjusting for dW, it was affected by sex, age, ethnicity, ABCG2, and SLC22A4. The time to reach the maximum concentration was influenced by sex, like half-life, which was also affected by SLC22A3. The volume of distribution and clearance was affected by sex, age, ethnicity and SLC22A3. Alternatively, the pharmacokinetics of metformin was unaffected by polymorphisms in ABCB1, SLC2A2, SLC22A2, or SLC47A1. Therefore, our study demonstrates that a multifactorial approach to all patient characteristics is necessary for better individualization.

Association Between Insulin-Like Growth Factor-1 and Social Cognition in Huntington's Disease.

Background: Insulin-like growth factor 1 (IGF-1) seems to be involved in the neural circuits associated with social cognition and brain structure. Objectives: To investigate the association of IGF-1 levels with social cognition and brain structure in Huntington's disease (HD). Methods: We evaluated social cognition using the Ekman test in 22 HD patients and 19 matched controls. Brain structure was assessed using standard volume-based voxel-based morphometry and surface-based cortical thickness pipeline. We analyzed the association of IGF-1 levels with social cognition and brain structure using adjusted regression analysis. Results: Social cognition was worse in HD patients (P < 0.001), on antidopaminergic drugs (P = 0.02), and with lower IGF-1 levels (P = 0.04). In neuroimaging analyses, lower IGF-1 levels were associated with social cognition impairment and atrophy mainly in frontotemporal regions (P < 0.05 corrected). Conclusions: In HD, abnormal IGF-1 function seems to be associated with brain atrophy leading to clinical deficits in social cognition.

Polymorphisms in the oxytocin receptor and their association with apathy and impaired social cognition in Huntington's disease.

BACKGROUND: Huntington's disease (HD) is a neurodegenerative disorder characterized by cognitive, motor, and neuropsychiatric manifestations. Oxytocin is a neuropeptide studied for its role as a neuromodulator regulating multiple behaviors linked to social cognition. Genetic variation of oxytocin receptor (OXTR) might interact in the etiology and development of several impaired social behaviors. Our aim was to study OXTR polymorphisms and their relationship with apathy and social cognition in HD. METHODS: OXTR was sequenced in 21 cases and 22 controls. We assessed apathy, anxiety, depression, and irritability (Hospital Anxiety and Depression Scale-Snaith Irritability scale, HADS-SIS) and social cognition (Ekman 60 faces test), motor symptoms and functionality with the total functional capacity (TFC), and the Unified HD rating Scale (UHDRS). RESULTS: We identified ten variants in OXTR. Three variants were classified as possibly damaging (p.Arg40Gly) or probably damaging (p.Leu46Pro, p.Thr102Asn). Subjects carrying the wild-type genotype of the synonymous variant p.Val45 showed a significantly lower score in the HADS-SIS scale, related to lower irritability (p = 0.013). The only subject carrying the heterozygous genotype of the synonymous variant p.Leu62 showed a significantly higher score on Ekman scale, compared to wild-type (p = 0.049); however, this finding was not confirmed after bootstrapping. CONCLUSION: Variations in OXTR could have a relevant role in the correct development of social and cognitive functions. Future approaches will include the molecular study of p.Arg40Gly, p.Leu46Pro, and p.Thr102Asn to confirm their pathogenicity, as well as the validation of the influence of p.Val45 and p.Leu62 variants for their involvement in irritability and social cognition in HD.

Use of Venetoclax in Patients with Relapsed or Refractory Acute Myeloid Leukemia: The PETHEMA Registry Experience.

The effectiveness of venetoclax (VEN) in relapsed or refractory acute myeloid leukemia (RR-AML) has not been well established. This retrospective, multicenter, observational database studied the effectiveness of VEN in a cohort of 51 RR-AML patients and evaluated for predictors of response and overall survival (OS). The median age was 68 years, most were at high risk, 61% received ≥2 therapies for AML, 49% had received hypomethylating agents, and ECOG was ≥2 in 52%. Complete remission (CR) rate, including CR with incomplete hematological recovery (CRi), was 12.4%. Additionally, 10.4% experienced partial response (PR). The CR/CRi was higher in combination with azacitidine (AZA; 17.9%) than with decitabine (DEC; 6.7%) and low-dose cytarabine (LDAC; 0%). Mutated NPM1 was associated with increased CR/CRi. Median OS was 104 days (95% CI: 56-151). For the combination with AZA, DEC, and LDAC, median OS was 120 days, 104 days, and 69 days, respectively; p = 0.875. Treatment response and ECOG 0 influenced OS in a multivariate model. A total of 28% of patients required interruption of VEN because of toxicity. Our real-life series describes a marginal probability of CR/CRi and poor OS after VEN-based salvage. Patients included had very poor-risk features and were heavily pretreated. The small percentage of responders did not reach the median OS.

Role of Pharmacogenetics in the Treatment of Acute Myeloid Leukemia: Systematic Review and Future Perspectives.

Acute myeloid leukemia (AML) is a heterogeneous disease characterized by remarkable toxicity and great variability in response to treatment. Plenteous pharmacogenetic studies have already been published for classical therapies, such as cytarabine or anthracyclines, but such studies remain scarce for newer drugs. There is evidence of the relevance of polymorphisms in response to treatment, although most studies have limitations in terms of cohort size or standardization of results. The different responses associated with genetic variability include both increased drug efficacy and toxicity and decreased response or resistance to treatment. A broad pharmacogenetic understanding may be useful in the design of dosing strategies and treatment guidelines. The aim of this study is to perform a review of the available publications and evidence related to the pharmacogenetics of AML, compiling those studies that may be useful in optimizing drug administration.

Consensus of experts from the Spanish Pharmacogenetics and Pharmacogenomics Society and the Spanish Society of Medical Oncology for the genotyping of DPYD in cancer patients who are candidates for treatment with fluoropyrimidines

5-Fluorouracil (5-FU) and oral fluoropyrimidines, such as capecitabine, are widely used in the treatment of cancer, especially gastrointestinal tumors and breast cancer, but their administration can produce serious and even lethal toxicity. This toxicity is often related to the partial or complete deficiency of the dihydropyrimidine dehydrogenase (DPD) enzyme, which causes a reduction in clearance and a longer half-life of 5-FU. It is advisable to determine if a DPD deficiency exists before administering these drugs by genotyping DPYD gene polymorphisms. The objective of this consensus of experts, in which representatives from the Spanish Pharmacogenetics and Pharmacogenomics Society and the Spanish Society of Medical Oncology participated, is to establish clear recommendations for the implementation of genotype and/or phenotype testing for DPD deficiency in patients who are candidates to receive fluoropyrimidines. The genotyping of DPYD previous to treatment classifies individuals as normal, intermediate, or poor metabolizers. Normal metabolizers do not require changes in the initial dose, intermediate metabolizers should start treatment with fluoropyrimidines at doses reduced to 50%, and poor metabolizers are contraindicated for fluoropyrimidines.

Use of Azacitidine or Decitabine for the Up-Front Setting in Acute Myeloid Leukaemia: A Systematic Review and Meta-Analysis.

Irruption of decitabine and azacitidine has led to profound changes in the upfront management of older acute myeloid leukaemia (AML). However, they have not been directly compared in a randomised clinical trial. In addition, there are no studies comparing the optimal treatment schedule of each drug in AML. A systematic review and meta-analysis on the efficacy of decitabine and azacitidine monotherapy in newly diagnosed AML was conducted. Randomised controlled trials and retrospective studies were included. A total of 2743 patients from 23 cohorts were analysed (10 cohorts of azacitidine and 13 of decitabine). Similar response rates were observed for azacitidine (38%, 95% CI: 30-47%) compared to decitabine (40%, 95% CI: 32-48%) (p = 0.825). Overall survival (OS) between azacitidine (10.04 months, 95% CI: 8.36-11.72) and decitabine (8.79 months, 95% CI: 7.62-9.96) was also similar (p = 0.386). Patients treated with azacitidine showed a lower median OS when azacitidine was administered for 5 days (6.28 months, 95% CI: 4.23-8.32) compared to the standard 7-day schedule (10.83 months, 95% CI: 9.07-12.59, p = 0.002). Among patients treated with decitabine, response rates and OS were not significantly different between 5-day and 10-day decitabine regimens. Despite heterogeneity between studies, we found no differences in response rates and OS in AML patients treated with azacitidine or decitabine.

Effects of Cytochrome P450 and Transporter Polymorphisms on the Bioavailability and Safety of Dutasteride and Tamsulosin.

Dutasteride and tamsulosin are one of the first-line combination therapies for the management of benign prostatic hyperplasia (BPH). Despite being more effective than monotherapies, they produce frequent adverse drug reactions (ADRs). Institutions such as Food and Drug Administration and European Medicines Agency recommend precaution with CYP2D6 poor metabolizers (PMs) that receive CYP3A4 inhibitors and tamsulosin. However, no specific pharmacogenetic guideline exists for tamsulosin. Furthermore, to date, no pharmacogenetic information is available for dutasteride. Henceforth, we studied the pharmacokinetics and safety of dutasteride/tamsulosin 0.5 mg/0.4 mg capsules according to 76 polymorphisms in 17 candidate pharmacogenes. The study population comprised 79 healthy male volunteers enrolled in three bioequivalence, phase-I, crossover, open, randomized clinical trials with different study designs: the first was single dose in fed state, the second was a single dose in fasting state, and the third was a multiple dose. As key findings, CYP2D6 PMs (i.e., *4/*4 and *4/*5 subjects) and intermediate metabolizers (IMs) (i.e., *1/*4, *1/*5, *4/*15 individuals) presented higher AUC (p = 0.004), higher t1/2 (p = 0.008), and lower Cl/F (p = 0.006) when compared with NMs (*1/*1 individuals) and UMs (1/*1 × 2 individuals) after multiple testing correction. Moreover, fed volunteers showed significantly higher tmax than fasting individuals. Nominally significant associations were observed between dutasteride exposure and CYP3A4 and CYP3A5 genotype and between tamsulosin and ABCG2, CYP3A5, and SLC22A1 genotypes. No association between the occurrence of adverse drug reactions and genotype was observed. Nonetheless, higher incidence of adverse events was found in a multiple-dose clinical trial. Based on our results, we suggest that dose adjustments for PMs and UMs could be considered to ensure drug safety and effectiveness, respectively. Further studies are warranted to confirm other pharmacogenetic associations.

PriME-PGx: La Princesa University Hospital Multidisciplinary Initiative for the Implementation of Pharmacogenetics.

The implementation of clinical pharmacogenetics in daily practice is limited for various reasons. Today, however, it is a discipline in full expansion. Accordingly, in the recent times, several initiatives promoted its implementation, mainly in the United States but also in Europe. In this document, the genotyping results since the establishment of our Pharmacogenetics Unit in 2006 are described, as well as the historical implementation process that was carried out since then. Finally, this progress justified the constitution of La Princesa University Hospital Multidisciplinary Initiative for the Implementation of Pharmacogenetics (PriME-PGx), promoted by the Clinical Pharmacology Department of Hospital Universitario de La Princesa (Madrid, Spain). Here, we present the initiative along with the two first ongoing projects: the PROFILE project, which promotes modernization of pharmacogenetic reporting (i.e., from classic gene-drug pair reporting to complete pharmacogenetic reporting or the creation of pharmacogenetic profiles specific to the Hospital's departments) and the GENOTRIAL project, which promotes the communication of relevant pharmacogenetic findings to any healthy volunteer participating in any bioequivalence clinical trial at the Clinical Trials Unit of Hospital Universitario de La Princesa (UECHUP).

High-Fat Breakfast Increases Bioavailability of Albendazole Compared to Low-Fat Breakfast: Single-Dose Study in Healthy Subjects.

Purpose: Albendazole is a benzimidazole carbamate drug with anthelmintic and antiprotozoal activity against intestinal and tissue parasites. It has been described that the administration with meals increases albendazole absorption. Our aim was to compare the systemic exposure in healthy volunteers of two albendazole formulations after a single oral dose under fed conditions and to evaluate the effect of breakfast composition on albendazole and albendazole sulfoxide bioavailability. Methods: 12 healthy volunteers were included in a 4-period, 4-sequence, crossover, open, randomized, bioequivalence clinical trial, including two stages to compare two formulations of albendazole. Single oral doses of 400 mg albendazole were administered under fed conditions (a low-fat breakfast in first stage and a high-fat breakfast in the second) separated by 7-day washout periods. Plasma albendazole and albendazole sulfoxide concentrations were measured by HPLC-MS/MS. Findings: Albendazole absorption was clearly influenced by the meal composition. A high-fat breakfast increased albendazole and albendazole sulfoxide area under the concentration-time curve (AUC) and maximum concentration (Cmax) by double, compared to a low-fat breakfast. The bioavailability of the two formulations was very similar, although the sample size was not sufficient to demonstrate bioequivalence because the intraindividual variability of albendazole was approximately 60%. Implications: The higher albendazole and albendazole sulfoxide levels when administered with a high-fat meal could be of importance in clinical practice. Since albendazole labeling recommends its administration with meals, it is necessary to insist on taking it with a fatty meal so that the effectiveness of albendazole is not compromised.

Influence of Genetic Polymorphisms on the Response to Tramadol, Ibuprofen, and the Combination in Patients With Moderate to Severe Pain After Dental Surgery.

PURPOSE: We aimed to elucidate the influence on analgesic effect of genetic polymorphisms in enzymes responsible for biotransformation of tramadol and ibuprofen or other possible genes involved in their mechanism of action. METHODS: The study population comprised 118 patients from a multicenter, randomized, double-blind, placebo-controlled, Phase III clinical trial that assessed the analgesic efficacy and tolerability of a single dose of ibuprofen (arginine)/tramadol 400/37.5 mg compared with ibuprofen arginine 400 mg alone, tramadol 50 mg alone, and placebo in patients with moderate to severe pain after dental surgery. We analyzed 32 polymorphisms in the cytochrome P450 (CYP) enzymes COMT, ABCB1, SLC22A1, OPRM1, and SLC22A1. FINDINGS: We did not find any statistically significant difference among CYP2C9 phenotypes related to ibuprofen response, although CYP2C9 poor metabolizers had a longer effect (higher pain relief at 6 hours). Likewise, we did not find any statistically significant difference among PTGS2 genotypes, contradicting previously publications. IMPLICATIONS: There was not a clear effect of CYP2D6 phenotype on tramadol response, although CYP2D6 poor metabolizers had a slower analgesic effect. Concerning the transport of CYP2D6, we observed a better response in individuals carrying ABCB1 mutated alleles, which might correlate with higher tramadol plasma levels. Finally, we found a statistically significant better response in patients carrying the OPRM1 A118G G allele, which contradicts the previous reports. Measuring the active metabolite O-desmethyl-tramadol formation would be of great importance to better evaluate this association because O-desmethyl-tramadol has a higher µ-opioid receptor affinity compared with the parent drug. EudraCT.ema.europa.eu identifier: 2013-004637-33.

HCP5 rs2395029 is a rapid and inexpensive alternative to HLA-B*57:01 genotyping to predict abacavir hypersensitivity reaction in Spain.

Abacavir (ABC) is an HIV nucleotide-analogue reverse transcriptase inhibitor that can produce a severe hypersensitivity reaction (ABC-HSR) in about 5% of the patients. The HLA-B*57:01 allele is associated with the development of ABC-HSR. Therefore, HLA-B*57:01 genotyping is required prior to the prescription of ABC. The technique routinely used in our laboratory is the sequence-specific oligonucleotide probes (SSOP) reverse hybridization method followed by Sanger sequencing. This technique is time-consuming and expensive. The single-nucleotide polymorphism (SNP) HCP5 rs2395029 was described to be in complete linkage disequilibrium with HLA-B*57:01. In this study, we aimed to assess the linkage disequilibrium between HCP5 rs2395029 and HLA-B*57:01 in patients receiving medical assistance at our hospital. We selected 226 HIV-infected patients from our hospital who had been routinely genotyped since 2009 with the SSOP and Sanger sequencing method: 49 HLA-B*57:01 positives and 177 negatives. We genotyped them for HCP5 rs2395019 by real time PCR (qPCR). We exploratory performed two copy number variation assays flanking HCP5 rs2395019 to explore possible deletions that could break the linkage disequilibrium with HLA-B*57:01. The concordance between HLA-B*57:01 and the HCP5 rs2395029 G allele was absolute, with a specificity and sensitivity of 100% (95% confidence interval: 93.0-100.0% and 98.0-100.0%, respectively) and estimated positive and negative predictive values of 84.4% (48.1-93.9%) and 99.9% (99.4-100.0%), respectively. No deletions were found at HCP5 flanking regions. The duration and cost of the SSOP-based method was considerably higher than the SNP-based method. Therefore, the HCP5 rs2395029 genotyping method may be alternatively used in the clinical practice.

Evaluation of Voriconazole CYP2C19 Phenotype-Guided Dose Adjustments by Physiologically Based Pharmacokinetic Modeling.

BACKGROUND AND OBJECTIVES: Controversy exists regarding dose adjustment in patients treated with voriconazole due to the severity of the infections for which it is prescribed. The Dutch Pharmacogenetics Working Group (DPWG) recommends a 50% dose increase or decrease for cytochrome P450 (CYP) 2C19 ultrarapid (UM) or poor (PM) metabolizers, respectively. In contrast, for the previous phenotypes, the Clinical Pharmacogenetics Implementation Consortium (CPIC) voriconazole guideline only recommends a change of treatment. Based on observed data from single-dose bioequivalence studies and steady-state observed concentrations, we aimed to investigate voriconazole dose adjustments by means of physiologically based pharmacokinetic (PBPK) modeling. METHODS: PBPK modeling was used to optimize voriconazole single-dose models for each CYP2C19 phenotype, which were extrapolated to steady state and evaluated for concordance with the therapeutic range of voriconazole. Based on optimized models, dose adjustments were evaluated for better adjustment to the therapeutic range. RESULTS: Our models suggest that the standard dose may only be appropriate for normal metabolizers (NM), although they would benefit from a 50-100% loading dose increase. Intermediate metabolizers (IMs) and PMs required a daily dose reduction of 50 and 75%, respectively. Rapid metabolizers (RMs) and UMs required a daily dose increase of 100% and 300%, respectively. CONCLUSION: The prescription of voriconazole in clinical practice should be personalized according to the CYP2C19 phenotype, followed by therapeutic drug monitoring of plasma concentrations to guide dose adjustment.