Slco1b1 phenotype and cyp3a5 polymorphism significantly affect atorvastatin bioavailability

Atorvastatin, prescribed for the treatment of hypercholesterolemia, demonstrated over-whelming benefits in reducing cardiovascular morbidity and mortality. However, many patients discontinue therapy due to adverse reactions, especially myopathy. The Dutch Pharmacogenetics Working Group (DPWG) recommends an alternative agent to atorvastatin and simvastatin or a dose adjustment depending on other risk factors for statin-induced myopathy in SLCO1B1 rs4149056 CC or TC carriers. In contrast, the Clinical Pharmacogenetics Implementation Consortium (CPIC) published their guideline on simvastatin, but not on atorvastatin. In this work, we aimed to demonstrate the effect of SLCO1B1 phenotype and other variants (e.g., in CYP3A4/5, UGT enzymes or SLC transporters) on atorvastatin pharmacokinetics. For this purpose, a candidate-gene pharmacogenetic study was proposed. The study population comprised 156 healthy volunteers enrolled in atorvastatin bioequivalence clinical trials. The genotyping strategy comprised a total of 60 variants in 15 genes. Women showed higher exposure to atorvastatin compared to men (p = 0.001), however this difference disappeared after dose/weight (DW) correction. The most relevant pharmacogenetic differences were the following: AUC/DW and Cmax /DW based on (a) SLCO1B1 phenotype (p < 0.001 for both) and (b) CYP3A5*3 (p = 0.004 and 0.018, respectively). As secondary findings: SLC22A1 *2/*2 genotype was related to higher Cmax/DW (ANOVA p = 0.030) and SLC22A1 *1/*5 genotype was associated with higher Vd/F (ANOVA p = 0.032) compared to SLC22A1 *1/*1, respectively. Finally, UGT2B7 rs7439366 *1/*1 genotype was associated with higher tmax as compared with the *1/*3 genotype (ANOVA p = 0.024). Based on our results, we suggest that SLCO1B1 is the best predictor for atorvastatin pharmacokinetic variability and that prescription should be adjusted based on it. We suggest that the CPIC should include atorvastatin in their statin-SLCO1B1 guidelines. Interesting and novel results were observed based on CYP3A5 genotype, which should be confirmed with further studies.G. Villapalos-García is co-financed by Instituto de Salud Carlos III (ISCIII) and the European Social Fund (PFIS predoctoral grant, number FI20/00090). M. Navares-Gómez is financed by the ICI20/00131 grant, Acción Estratégica en Salud 2017-2020, ISCII

ABCB1 C3435T, G2677T/A and C1236T variants have no effect in eslicarbazepine pharmacokinetics

Eslicarbazepine acetate is a third-generation anti-epileptic prodrug quickly and extensively transformed to eslicarbazepine after oral administration. Reduction in seizure frequency in patients managed with eslicarbazepine is only partial in the majority of patients and many of them suffer considerable ADRs that require a change of treatment. The P-glycoprotein, encoded by the ABCB1 gene, is expressed throughout the body and can impact the pharmacokinetics of several drugs. In terms of epilepsy treatment, this transporter was linked to drug-resistant epilepsy, as it conditions drug access into the brain due to its expression at the blood-brain barrier. Therefore, we aimed to investigate the impact of three ABCB1 common polymorphisms (i.e., C3435T, or rs1045642, G2677A or rs2032582 and C1236T or rs1128503) in the pharmacokinetics and safety of eslicarbazepine. For this purpose, 22 healthy volunteers participating in a bioequivalence clinical trial were recruited. No significant relationship was observed between sex, race and ABCB1 polymorphism and eslicarbazepine pharmacokinetic variability. In contrast, ABCB1 C1236T C/C diplotype was significantly related to the occurrence of ADRs: one volunteer with this genotype suffered dizziness, somnolence and hand paresthesia, while no other volunteer suffered any of these ADRs (p < 0.045). To the best of our knowledge, this is the first study published to date evaluating eslicarbazepine pharmacogenetics. Further studies with large sample sizes are needed to compare the results obtained here.G. Villapalos-García is co-financed by Instituto de Salud Carlos III (ISCIII) and the European Social Fund (PFIS predoctoral grant, number FI20/00090). M. Navares-Gómez is financed by the ICI20/00131 grant, Acción Estratégica en Salud 2017–2020, ISCIII

Impact of polymorphisms in transporter and metabolizing enzyme genes on olanzapine pharmacokinetics and safety in healthy volunteers

Olanzapine is an atypical antipsychotic widely used for the treatment of schizophrenia, which often causes serious adverse drug reactions. Currently, there are no clinical guidelines implementing pharmacogenetic information on olanzapine. Moreover, the Dutch Pharmacogenomics Working Group (DPWG) states that CYP2D6 phenotype is not related to olanzapine response or side effects. Thus, the objective of this candidate-gene study was to investigate the effect of 72 polymorphisms in 21 genes on olanzapine pharmacokinetics and safety, including transporters (e.g. ABCB1, ABCC2, SLC22A1), receptors (e.g. DRD2, HTR2C), and enzymes (e.g. UGT, CYP and COMT), in a cohort of healthy volunteers. Polymorphisms in CYP2C9, SLC22A1, ABCB1, ABCC2, and APOC3 were related to olanzapine pharmacokinetic variability. The incidence of adverse reactions was related to several genes: palpitations to ABCB1 and SLC22A1, asthenia to ABCB1, somnolence to DRD2 and ABCB1, and dizziness to CYP2C9. However, further studies in patients are warranted to confirm the influence of these genetic polymorphisms on olanzapine pharmacokinetics and tolerability.D. Koller is financed by the H2020 Marie Sklodowska-Curie Innovative Training Network721236 grant. Marcos Navares-G´omez is cofinaneced by the European Social Fund and the Youth European Initiative, grant number PEJ-2018-TL/MD-1108

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 individualizationThe project was financed by the Regional Health Management of Castilla y León (GRS 2432/A/21) and partially by Fundación Burgos por la Investigación de la Salud (FBIS). M.S.R. research is supported by Instituto de Salud Carlos III (ISCIII), Spanish Ministry of Science and Innovation, through the Sara Borrell Program (CD21/00022). G.V.G. is cofinanced by Instituto de Salud Carlos III (ISCIII) and the European Social Fund (PFIS predoctoral grant, number FI20/00090). M.N.G. is financed by the ICI20/00131 grant, Acción Estratégica en Salud 2017–2020, ISCIII. P.Z. is financed by Universidad Autónoma de Madrid, Margarita Salas contract, grants for the requalification of the Spanish university system. The MassArray genotyping service was carried out at the Spanish genotyping center–Centro Español de Genotipado CEGEN-PRB3-ISCIII, which is supported by grant PT17/0019 of the PE I+D+i 2013–2016, funded by ISCIII and European Regional Development Fund ERD

Dasatinib-induced spleen contraction leads to transient lymphocytosis

The tyrosine kinase inhibitor dasatinib is approved for Philadelphia chromosome–positive leukemia, including chronic myeloid leukemia (CML). Although effective and well tolerated, patients typically exhibit a transient lymphocytosis after dasatinib uptake. To date, the underlying physiological process linking dasatinib to lymphocytosis remains unknown. Here, we used a small rodent model to examine the mechanism of dasatinib-induced lymphocytosis, focusing on lymphocyte trafficking into and out of secondary lymphoid organs. Our data indicate that lymphocyte homing to lymph nodes and spleen remained unaffected by dasatinib treatment. In contrast, dasatinib promoted lymphocyte egress from spleen with kinetics consistent with the observed lymphocytosis. Unexpectedly, dasatinib-induced lymphocyte egress occurred independently of canonical sphingosine-1-phosphate–mediated egress signals; instead, dasatinib treatment led to a decrease in spleen size, concomitant with increased splenic stromal cell contractility, as measured by myosin light chain phosphorylation. Accordingly, dasatinib-induced lymphocytosis was partially reversed by pharmacological inhibition of the contraction-promoting factor Rho-rho associated kinase. Finally, we uncovered a decrease in spleen size in patients with CML who showed lymphocytosis immediately after dasatinib treatment, and this reduction was proportional to the magnitude of lymphocytosis and dasatinib plasma levels. In summary, our work provides evidence that dasatinib-induced lymphocytosis is a consequence of drug-induced contractility of splenic stromal cell

Genetic variation in CYP2D6 and SLC22A1 affects amlodipine pharmacokinetics and safety

Amlodipine is an antihypertensive drug with unknown pharmacogenetic biomarkers. This research is a candidate gene study that looked for associations between amlodipine pharmacokinetics and safety and pharmacogenes. Pharmacokinetic and safety data were taken from 160 volunteers from eight bioequivalence trials. In the exploratory step, 70 volunteers were genotyped for 44 polymorphisms in different pharmacogenes. CYP2D6 poor metabolizers (PMs) showed higher half-life (t1/2) (univariate p-value (puv) = 0.039, multivariate p-value (pmv) = 0.013, β = −5.31, R2 = 0.176) compared to ultrarapid (UMs), normal (NMs) and intermediate metabolizers (IMs). SLC22A1 rs34059508 G/A genotype was associated with higher dose/weight-corrected area under the curve (AUC72/DW) (puv = 0.025; pmv = 0.026, β = 578.90, R2 = 0.060) compared to the G/G genotype. In the confirmatory step, the cohort was increased to 160 volunteers, who were genotyped for CYP2D6, SLC22A1 and CYP3A4. In addition to the previous associations, CYP2D6 UMs showed a lower AUC72/DW (puv = 0.046, pmv = 0.049, β = −68.80, R2 = 0.073) compared to NMs, IMs and PMs and the SLC22A1 rs34059508 G/A genotype was associated with thoracic pain (puv = 0.038) and dizziness (puv = 0.038, pmv = 0.014, log OR = 10.975). To our knowledge, this is the first work to report a strong relationship between amlodipine and CYP2D6 and SLC22A1. Further research is needed to gather more evidence before its application in clinical practic

NAT2 phenotype alters pharmacokinetics of rivaroxaban in healthy volunteers

Rivaroxaban is a direct inhibitor of factor Xa, a member of direct oral anticoagulant group of drugs (DOACs). Despite being a widely extended alternative to vitamin K antagonists (i.e., acenocoumarol, warfarin) the interindividual variability of DOACs is significant, and may be related to adverse drug reaction occurrence or drug inefficacy, namely hemorrhagic or thromboembolic events. Since there is not a consistent analytic practice to monitor the anticoagulant activity of DOACs, previously reported polymorphisms in genes coding for proteins responsible for the activation, transport, or metabolism of DOACs were studied. The study population comprised 60 healthy volunteers, who completed two randomized, crossover bioequivalence clinical trials between two different rivaroxaban formulations. The effect of food, sex, biogeographical origin and 55 variants (8 phenotypes and 47 single nucleotide polymorphisms) in drug metabolizing enzyme genes (such as CYP2D6, CYP2C9, NAT2) and transporters (namely, ABCB1, ABCG2) on rivaroxaban pharmacokinetics was tested. Individuals dosed under fasting conditions presented lower tmax (2.21 h vs 2.88 h, β = 1.19, R2 =0.342, p = 0.012) compared to fed volunteers. NAT2 slow acetylators presented higher AUC∞ corrected by dose/weight (AUC∞/DW; 8243.90 vs 7698.20 and 7161.25 h*ng*mg /ml*kg, β = 0.154, R2 =0.250, p = 0.044), higher Cmax/DW (1070.99 vs 834.81 and 803.36 ng*mg /ml*kg, β = 0.245, R2 =0.320, p = 0.002), and lower tmax (2.63 vs 3.19 and 4.15 h, β = − 0.346, R2 =0.282, p = 0.047) than NAT2 rapid and intermediate acetylators. No other association was statistically significant. Thus, slow NAT2 appear to have altered rivaroxaban pharmacokinetics, increasing AUC∞ and Cmax. Nonetheless, further research should be conducted to verify NAT2 involvement on rivaroxaban pharmacokinetics and to determine its clinical significanceGonzalo Villapalos-García was co-financed by Instituto de Salud Carlos III (ISCIII) and the European Social Fund (PFIS predoctoral grant, number FI20/00090). Marcos Navares-Gomez ´ was financed by the ICI20/00131 grant, Accion ´ Estrat´egica en Salud 2017–2020, ISCIII. Pablo Zubiaur is financed by Universidad Autonoma ´ de Madrid, Margarita Salas contract, grants for the requalification of the Spanish university system. Paula Soria-Chacartegui is financed by Universidad Autonoma ´ de Madrid (FPI-UAM, 2021). This study was co-financed by Instituto de Salud Carlos III (ISCIII) and the European Regional Development Fund (ERDF) “A way of making Europe”, number PI19/0093

Occurrence of SARS-CoV-2 viremia is associated with genetic variants of genes related to COVID-19 pathogenesis

IntroductionSARS-CoV-2 viral load has been related to COVID-19 severity. The main aim of this study was to evaluate the relationship between SARS-CoV-2 viremia and SNPs in genes previously studied by our group as predictors of COVID-19 severity.Materials and methodsRetrospective observational study including 340 patients hospitalized for COVID-19 in the University Hospital La Princesa between March 2020 and December 2021, with at least one viremia determination. Positive viremia was considered when viral load was above the quantifiable threshold (20 copies/ml). A total of 38 SNPs were genotyped. To study their association with viremia a multivariate logistic regression was performed.ResultsThe mean age of the studied population was 64.5 years (SD 16.6), 60.9% patients were male and 79.4% white non-Hispanic. Only 126 patients (37.1%) had at least one positive viremia. After adjustment by confounders, the presence of the minor alleles of rs2071746 (HMOX1; T/T genotype OR 9.9 p &lt; 0.0001), rs78958998 (probably associated with SERPING1 expression; A/T genotype OR 2.3, p = 0.04 and T/T genotype OR 12.9, p &lt; 0.0001), and rs713400 (eQTL for TMPRSS2; C/T + T/T genotype OR 1.86, p = 0.10) were associated with higher risk of viremia, whereas the minor alleles of rs11052877 (CD69; A/G genotype OR 0.5, p = 0.04 and G/G genotype OR 0.3, p = 0.01), rs2660 (OAS1; A/G genotype OR 0.6, p = 0.08), rs896 (VIPR1; T/T genotype OR 0.4, p = 0.02) and rs33980500 (TRAF3IP2; C/T + T/T genotype OR 0.3, p = 0.01) were associated with lower risk of viremia.ConclusionGenetic variants in HMOX1 (rs2071746), SERPING1 (rs78958998), TMPRSS2 (rs713400), CD69 (rs11052877), TRAF3IP2 (rs33980500), OAS1 (rs2660) and VIPR1 (rs896) could explain heterogeneity in SARS-CoV-2 viremia in our population

Validación del polimorfismo rs2395029 del gen HCP5 para la predicción de hipersensibilidad a abacavir

Abacavir is one of the most widely used drugs in the treatment of HIV. However, 4% of patients taking abacavir suffer from a life-threatening hypersensitivity reaction. Multiple research groups have confirmed the association between hypersensitivity and a particular genotype of a component of the major human histocompatibility complex type I: the HLA-B*57:01 allele. Predictive tests are, therefore, performed on all HIV-positive patients prior to abacavir treatment, as recommended by the drug label. The procedure used at Hospital Universitario de La Princesa to determine the HLA-B*57:01 genotype consists of inverse hybridization prior to sequencing. This technique determines the HLA-B allele but lacks the resolution necessary to discriminate the HLA-B*57:01 subvariant. Thus, the rest of the HLA-B genotypes other than HLA-B*57:01 are discriminated, for which abacavir can be administered. In patients carrying the HLA-B*57 allele, a second determination is made by PCR and Sanger sequencing to confirm the existence of HLA-B*57:01. Therefore, the current procedure is technically complex, costly and involves a moderate response time; therefore, substitution by another method, such as genotyping using hybridization probes, will shorten response times and reduce costs. The objective of this study is to validate a method based on the analysis of a theoretically perfect linkage disequilibrium between HLA-B*57:01 and the G allele of the rs2395029 polymorphism in the HLA complex P5 gene (HCP5), to be used as a biomarker predictive for abacavir hypersensitivity. From 1225 patients genotyped for HLA-B since 2008, 49 patients positive and 177 negatives for HLA-B*57:01 were genotyped by quantitative PCR with allele-specific hybridization probes for polymorphism rs239529. Specificity and sensitivity values were 100%, which 95% confidence intervals were 93−100% and 98−100% respectively. Positive predictive value was estimated as 84.4%, which 95% confidence interval was 48.1−93.9%. The negative predictive value was estimated as 99.9%; likewise, when setting the confidence level at 95%, the confidence level was 99.4−100%. A quantitative study of HCP5 was also performed, since this gene is a copy number variation zone, so we studied whether 5 patients apparently homozygous for the allele G of HCP5 but heterozygous for HLA-B had the most frequent deletions described for this zone. The results showed that they do not have such deletions. Also, economic and practical comparison between both methods resulted in an improvement in time and cost if the HCP5 rs2395029 method is incorporated. In conclusion, HCP5 genotyping is a viable alternative method for predicting hypersensitivity to abacavir, being able to replace the conventional HLA-B*57:01 typing

The Pharmacogenetics of Treatment with Quetiapine

Quetiapine is a second-generation antipsychotic used for the treatment of schizophrenia, depression and bipolar disorder. The aim of this traditional review was to summarize the available pharmacogenetic information on this drug and to conclude about its clinical relevance. For this purpose, bibliographic research was performed in the Pharmacogenomics Knowledge Base (PharmGKB) database. A total of 23 articles were initially retrieved, of which 15 were finally included. A total of 19 associations were observed between 15 genes, such as CYP3A4, CYP3A5, COMT or MC4R, and 29 clinical events. No associations were consistently replicated between pharmacogenetic biomarkers and clinical events, except for that between the CYP3A4 phenotype and quetiapine exposure, which was the only one considered clinically relevant. Consistently, the DPWG published a clinical guideline on this association, where dose adjustments for CYP3A4 poor metabolizers (PMs) are indicated to prevent the occurrence of adverse drug reactions (ADRs)