Use of exposure data to establish causality in drug–adverse event relationships: an example with desvenlafaxine

Causality algorithms help establish relationships between drug use and adverse event (AE) occurrence. High drug exposure leads to a higher likelihood of an AE being classified as an adverse drug reaction (ADR). However, there is a knowledge gap regarding what concentrations are predictive of ADRs, as this has not been systematically studied. In this work, the Spanish Pharmacovigilance System (SEFV) algorithm was used to define the relationship between the AE occurrence and drug administration in 178 healthy volunteers participating in five desvenlafaxine single-dose clinical trials, a selective serotonin and norepinephrine reuptake inhibitor that may cause dizziness, headache, nausea, dry mouth, constipation and hyperhidrosis. Eighty-three subjects presented 172 AEs that were classified as possible (101), conditional (31), unrelated (24) and probable (16). AUC∞ and Cmax were significantly higher in volunteers with vs. without ADRs (5981.24 ng·h/mL and 239.06 ng/mL and 4770.84 ng·h/mL and 200.69 ng/mL, respectively). Six of 19 subjects with conditional AEs with an SEFV score of 3 points presented an AUC∞ ≥ 6500 ng·h/mL or a Cmax ≥ 300 ng/mL (i.e., above percentile 75) and were summed one point on their SEFV score and classified as “possible” (4 points), improving the capacity of ADR detectionAndrea Rodríguez-Lopez contracts are financed by the Programa Investigo (NextGenerationEU funds of the Recovery and Resilience Facility), fellowship number 2022-C23.I01.P03.S0020-0000031. P. Zubiaur is financed by the Universidad Autónoma de Madrid, Margarita Salas contract, grants for the requalification of the Spanish university syste

Pharmacogenetics of Donepezil and Memantine in Healthy Subjects

Donepezil and memantine are the most common drugs used for Alzheimer’s disease. Their low effectiveness could partly be explained by genetic factors. Thus, we aim to identify Single Nucleotide Polymorphisms (SNPs) associated with pharmacokinetics, pharmacodynamics, and the safety of donepezil and memantine. For this regard, 25 volunteers enrolled in a bioequivalence clinical trial were genotyped for 67 SNPs in 21 genes with a ThermoFisher QuantStudio 12K Flex Open‐ Array. The statistical strategy included a univariate analysis that analyzed the association of these SNPs with pharmacokinetic parameters or the development of adverse drug reactions (ADRs) fol-lowed by a Bonferroni‐corrected multivariate regression. Statistical analyses were performed with SPSS software v.21 and R commander (version v3.6.3). In the univariate analysis, fourteen and six-teen SNPs showed a significant association with memantine’s and donepezil’s pharmacokinetic pa-rameters, respectively. Rs20417 (PTGS2) was associated with the development of at least one ADR. However, none of these associations reached the significance threshold in the Bonferroni‐corrected multivariate analysis. In conclusion, we did not observe any significant association of the SNPs analyzed with memantine and donepezil pharmacokinetics or ADRs. Current evidence on memantine and donepezil pharmacogenetics does not justify their inclusion in pharmacogenetic guidelines.M. Navares is financed by the ICI20/00131 grant, Acción Estratégica en Salud 2017-2020, ISCIII. P. Zubiaur’s contract with CIBERehd is financed by the “Infraestructura de Medicina de Precisión asociada a la Ciencia y Tecnología (IMPaCT, IMP/00009)”, Instituto de Salud Carlos III (ISCIII

Association between CYP2C19 and CYP2B6 phenotypes and the pharmacokinetics and safety of diazepam

Diazepam is a benzodiazepine (BZD) used worldwide for a variety of conditions. Long-term use of diazepam increases the risk for developing tolerance and dependence and for the occurrence of adverse drug reactions (ADRs). CYP3A4 and CYP2C19 mainly metabolize diazepam and are therefore the primary pharmacogenetic candidate biomarkers. In this work, we aimed to explore the impact of CYP3A4 and CYP2C19 phenotypes and of 99 additional variants in other 31 pharmacogenes (including other CYP, UGT, NAT2 and CES enzymes, ABC and SLC transporters) on diazepam pharmacokinetic variability and safety. 30 healthy volunteers that had participated in a single-dose bioequivalence clinical trial of two diazepam formulations were enrolled in the present candidate gene pharmacogenetic study. CYP2C19 poor metabolizers (PMs) showed an almost 2-fold increase in AUC0-∞/DW compared to rapid (RMs) or normal (NM) metabolizers, and a 1.46-fold increase compared to intermediate metabolizers (IMs). CYP2B6 PMs showed a 2,74-fold higher AUC0-∞/DW compared to RMs, and 2.10-fold compared to NMs (p < 0.007). A dose reduction of 25–50 % may be appropriate for CYP2C19 or CYP2B6 PMs to avoid ADRs, dependence and tolerance. Combined CYP2C19 +CYP2B6 PMs may not use diazepam or sharper dose adjustments (e.g., a dose reduction of 50–70 %) may be advisable. To our knowledge, this is the first work to report a strong relationship between CYP2B6 phenotype and diazepam pharmacokinetics. Additional nominal associations (i.e., 0.007 <p < 0.05) between ABCG2, ABCB1, NAT2 and UGT1A4 polymorphisms and pharmacokinetic variability were observed; further research should elaborate on the clinical relevance of the described association

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

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

SLCO1B1 and ABCG2 genotype-informed phenotypes are related to variation in ramipril exposure

Ramipril is an angiotensin-converting enzyme inhibitor used for hypertension and heart failure management. To date, scarce literature is available on pharmacogenetic associations affecting ramipril. The goal of this study was to investigate the effect of 120 genetic variants in 34 pharmacogenes (i.e., genes encoding for enzymes like CYPs or UGTs and transporters like ABC or SLC) on ramipril pharmacokinetic variability and adverse drug reaction (ADR) incidence. Twenty-nine healthy volunteers who had participated in a single-dose bioequivalence clinical trial of two formulations of ramipril were recruited. A univariate and multivariate analysis searching for associations between genetic variants and ramipril pharmacokinetics was performed. SLCO1B1 and ABCG2 genotype-informed phenotypes strongly predicted ramipril exposure. Volunteers with the SLCO1B1 decreased function (DF) phenotype presented around 1.7-fold higher dose/weight-corrected area under the curve (AUC/DW) than volunteers with the normal function (NF) phenotype (univariate p-value [puv] < 0.001, multivariate p-value [pmv] < 0.001, β = 0.533, R2 = 0.648). Similarly, volunteers with ABCG2 DF + poor function (PF) phenotypes presented around 1.6-fold higher AUC/DW than those with the NF phenotype (puv = 0.011, pmv < 0.001, β = 0.259, R2 = 0.648). Our results suggest that SLCO1B1 and ABCG2 are important transporters to ramipril pharmacokinetics, and their genetic variation strongly alters its pharmacokinetics. Further studies are required to confirm these associations and their clinical relevanceFI20/00090, ICI20/0013

Benefits of the application of heat and pressure on peripheral venous cannulation in adults: A randomized controlled trial

15 p.Aim: To evaluate the effectiveness of the application of topical heat, high pressure or a combination of both on antebrachial venous cannulation. Design: A cross-over clinical trial blinded for haemolysis analysis. Methods: This cross-over clinical trial with two periods was performed in the Clinical Trial Unit of Hospital Universitario de La Princesa (Madrid) during June?July of 2017 in 59 healthy adults who were randomly allocated to one of three interventions: (1) Using dry topical heat for 7 min produced by two hot seed bags (N = 21), (2) Applying controlled pressure from a sphygmomanometer inflated to 100 mmHg (N = 18) and (3) combining heat and pressure (N = 20) in one period out of two. All interventions were contrasted to standard clinical practice in the other period. The comparator involved a standard tourniquet around the upper arm to restrict venous blood flow. The primary outcome was effectiveness measured as vein cannulation at first attempt. Secondary outcomes were vein perception, pain, haemolysis in blood samples and adverse events. Results: All the interventions were more effective than comparator. Vein perception was optimized in about all individuals. Moreover, pain relief was significantly higher when high pressure was applied. Haemolysis was not affected in any of the three interventions. In addition, no serious adverse events appeared. Conclusion: High pressure is determined to be the most effective in vein catheterization, pain relief, vein perception and quality of blood sample inalterability. Moreover, it is safe considering that only one adverse event appeared. Impact: Vein cannulation is a very common invasive technique, where repeated failures have been registered. Thus, we consider it relevant to develop interventions to achieve venous catheterization at first attempt to alleviate the pain and anxiety associated with this technique. We advocate using high pressure intervention for emergency, due to swiftest method and feasible in case of lacking resources, such as sphygmomanometers in the ambulance

Bioavailability of Oniria^®, a melatonin prolonged-release formulation, versus immediate-release melatonin in healthy volunteers

Background: Melatonin is an endogenous substance which plays a key role in sleep induction by reducing sleep onset latency; it has been approved by the European Food Safety Authority as a food supplement for exogenous administration. Oniria® is a food supplement formulated as 1.98 mg of prolonged-release melatonin tablets; it displays a dual dissolution profile in vitro. Objectives: The main objective of the present study was to evaluate the relative oral bioavailability of Oniria®, in comparison with immediate-release tablets (IRT) with a similar melatonin content as a reference. We also attempted to characterize the circadian rhythm of endogenous melatonin. Methods: We performed an open-label, cross-over, randomized, phase I clinical study with two sequences and three periods involving 14 healthy volunteers. We characterized the endogenous melatonin circadian profile (period 1) and pharmacokinetics (PK) of both Oniria® and the reference melatonin (periods 2 and 3). Results: Two phases were clearly differentiated in the PK profile of Oniria®. An initial one, from dosing up to 2 h, and a delayed one from 2 to 11 h post-administration. During the initial phase, both melatonin formulations were equivalent, with a Cmax value close to 4000 pg/mL. However, in the delayed phase, Oniria® showed significantly higher melatonin concentrations than the IRT (three times higher at 4–6 h post-administration). Moreover, Oniria® exhibited concentrations above the endogenous melatonin peak of 80 pg/mL for up to 2.5 h versus the reference formulation, potentially suggesting an effect of Oniria®, not only in the induction of sleep, but also in the maintenance. Conclusion: Oniria® could be a highly promising food supplement, not only for sleep induction but also for the maintenance of sleepThe study was funded by the sponsor ITF Research Pharma S.L.

Prediction models for voriconazole pharmacokinetics based on pharmacogenetics: AN exploratory study in a Spanish population

Individualisation of the therapeutic strategy for the oral antifungal agent voriconazole (VCZ) is extremely important for treatment optimisation. To date, regulatory agencies include CYP2C19 as the only major pharmacogenetic (PGx) biomarker in their dosing guidelines; however, the effect of other genes might be important for VCZ dosing prediction. We developed an exploratory PGx study to identify new biomarkers related to VCZ pharmacokinetics. We first designed a ‘clinical practice VCZ-AUC prediction model’ based on CYP2C19 to be used as a reference model in this study. We then designed a multifactorial polygenic prediction model and found that genetic variability in FMO3, NR1I2, POR, CYP2C9 and CYP3A4 partially contributes to VCZ total area under the concentration–time curve (AUC0–∞) interindividual variability, and its inclusion in VCZ AUC0–∞ prediction algorithms improves model precision. To our knowledge, there are no PGx studies specifically relating POR, FMO3 and NR1I2 polymorphisms to VCZ pharmacokinetic variability. Further research is needed in order to test the model proposed hereThe voriconazole bioequivalence study was funded by Labora- torios Normon (Madrid, Spain). The research project has been co- financed by the Ministerio de Economia y Competitividad within the INNPACTO program [IPT-2012-0576-090 0 0 0] and the European Regional Development Fund (ERDF ‘A way to achieve Europe’