The Pharmacogenomics Global Research Network Implementation Working Group: global collaboration to advance pharmacogenetic implementation.

Pharmacogenetics promises to optimize treatment-related outcomes by informing optimal drug selection and dosing based on an individual's genotype in conjunction with other important clinical factors. Despite significant evidence of genetic associations with drug response, pharmacogenetic testing has not been widely implemented into clinical practice. Among the barriers to broad implementation are limited guidance for how to successfully integrate testing into clinical workflows and limited data on outcomes with pharmacogenetic implementation in clinical practice. The Pharmacogenomics Global Research Network Implementation Working Group seeks to engage institutions globally that have implemented pharmacogenetic testing into clinical practice or are in the process or planning stages of implementing testing to collectively disseminate data on implementation strategies, metrics, and health-related outcomes with the use of genotype-guided drug therapy to ultimately help advance pharmacogenetic implementation. This paper describes the goals, structure, and initial projects of the group in addition to implementation priorities across sites and future collaborative opportunities.

Precision Antiplatelet Therapy after Percutaneous Coronary Intervention (Precision PCI) Registry - Informing optimal antiplatelet strategies.

Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 receptor inhibitor (clopidogrel, prasugrel, or ticagrelor) is indicated after percutaneous coronary intervention (PCI) to reduce the risk of atherothrombotic events. Approximately 30% of the US population has a CYP2C19 no-function allele that reduces the effectiveness of clopidogrel, but not prasugrel or ticagrelor, after PCI. We have shown improved outcomes with the integration of CYP2C19 genotyping into clinical care to guide the selection of prasugrel or ticagrelor in CYP2C19 no-function allele carriers. However, the influence of patient-specific demographic, clinical, and other genetic factors on outcomes with genotype-guided DAPT has not been defined. In addition, the impact of genotype-guided de-escalation from prasugrel or ticagrelor to clopidogrel in patients without a CYP2C19 no-function allele has not been investigated in a diverse, real-world clinical setting. The Precision Antiplatelet Therapy after Percutaneous Coronary Intervention (Precision PCI) Registry is a multicenter US registry of patients who underwent PCI and clinical CYP2C19 testing. The registry is enrolling a diverse population, assessing atherothrombotic and bleeding events over 12 months, collecting DNA samples, and conducting platelet function testing in a subset of patients. The registry aims to define the influence of African ancestry and other patient-specific factors on clinical outcomes with CYP2C19-guided DAPT, evaluate the safety and effectiveness of CYP2C19-guided DAPT de-escalation following PCI in a real-world setting, and identify additional genetic influences of clopidogrel response after PCI, with the ultimate goal of establishing optimal strategies for individualized antiplatelet therapy that improves outcomes in a diverse, real-world population.

Evaluating the Effect of Estimating Renal Function With the CKD-EPI 2021 Equation on the ABCD-GENE Score for Clopidogrel Response Prediction.

The ABCD-GENE score was developed to predict poor response to clopidogrel and includes Age, Body mass index, Chronic kidney disease (CKD; estimated glomerular filtration rate [eGFR] < 60 mL/min/1.73 m2), Diabetes, and CYP2C19 GENE variants; a score ≥ 10 is predictive of reduced clopidogrel effectiveness after percutaneous coronary intervention (PCI). Estimation of GFR without a race variable via the CKD-EPI Scr 2021 equation is now recommended. We examined the impact of using the CKD-EPI Scr 2021 vs. 2009 equation on the ABCD-GENE score for post-PCI patients. A total of 4335 adult patients (n = 925 Black) who underwent PCI and CYP2C19 genotyping were included, with GFR estimated for each patient via the CKD-EPI Scr 2021 and CKD-EPI 2009 equations. The ABCD-GENE score, calculated based on each GFR estimation, was compared. With the CKD-EPI Scr 2021 vs. 2009 equation, median (IQR) eGFR was lower (74 [55-94] vs. 81 [60-103] mL/min/1.73 m2, P < 0.001), and CKD prevalence was higher (31% vs. 25%, P < 0.001) among Black patients, whereas eGFR was higher (85 [65-99] vs. 80 [61-94] mL/min/1.73m2, P < 0.001), and CKD prevalence was lower (20% vs. 24%, P < 0.001) in non-Black patients. This led to 12 (1%) Black patients being reclassified from low to high risk of poor clopidogrel response and 30 (1%) non-Black patients being recategorized from high to low risk (P < 0.001 for both comparisons). Removal of the race variable from GFR estimation significantly impacted the prediction of clopidogrel effectiveness via the ABCD-GENE score.

Value of Vitamin D Metabolite Ratios in 3 Patients as Diagnostic Criteria to Assess Vitamin D Status.

Although clinical guidelines recommend measuring total plasma 25-hydroxyvitamin D (25[OH]D) to assess vitamin D (VitD) status, this index does not account for 3-fold inter-individual variation in VitD binding protein (VDBP) level. We present 3 individuals with total plasma 25(OH)D levels of 10.8 to 12.3 ng/mL (27-30.7 nmol/L). Because Endocrine Society guidelines define VitD deficiency as 25(OH)D ≤ 20 ng/mL (50 nmol/L), all 3 would be judged to be VitD deficient. VitD3 supplementation increased 25(OH)D to the range of 31.7 to 33.8 ng/mL (79.1-84.4 nmol/L). Patient #1 exhibited secondary hyperparathyroidism; VitD3 supplementation decreased parathyroid hormone (PTH) by 34% without a clinically significant change in PTH levels in the other 2 individuals. Thus, 25(OH)D level did not distinguish between the 1 patient who had secondary hyperparathyroidism and the 2 who did not. We therefore inquired whether VitD metabolite ratios (which are VDBP-independent) might distinguish among these 3 individuals. Of all the assessed ratios, the 1,25(OH)2D/24,25(OH)2D ratio was the most informative, which had a value of 102 pg/ng in the individual with secondary hyperparathyroidism but lower values (41 and 20 pg/ng) in the other 2 individuals. These cases illustrate the value of the 1,25(OH)2D/24,25(OH)2D ratio to provide clinically relevant information about VitD status.

CYP2C19 Genotype Is Associated With Adverse Cardiovascular Outcomes in Black Patients Treated With Clopidogrel Undergoing Percutaneous Coronary Intervention.

BACKGROUND: Cytochrome P450 2C19 (CYP2C19) intermediate and poor metabolizer patients exhibit diminished clopidogrel clinical effectiveness after percutaneous coronary intervention (PCI). However, outcome studies to date have lacked racial diversity. Thus, the impact of CYP2C19 genotype on cardiovascular outcomes in patients treated with clopidogrel who identify as Black or African American remains unclear. METHODS AND RESULTS: Adults among 5 institutions who self-identified as Black or African American, underwent PCI and clinical CYP2C19 genotyping, and were treated with clopidogrel were included. Data were abstracted from health records. Major atherothrombotic (composite of death, myocardial infarction, ischemic stroke, stent thrombosis, or revascularization for unstable angina) and bleeding event rates within 1 year after PCI were compared across CYP2C19 metabolizer groups using multivariable Cox regression adjusted for potential confounders and baseline variables meeting a threshold of P<0.10. The population included 567 Black patients treated with clopidogrel (median age, 62 years; 46% women; 70% with an acute coronary syndrome indication for PCI). Major atherothrombotic events rates were significantly higher among clopidogrel-treated intermediate and poor metabolizers (24 of 125 [19.2%]) versus patients treated with clopidogrel without a no function allele (43 of 442 [9.7%]; 35.1 versus 15.9 events per 100 person-years; adjusted hazard ratio, 2.00 [95% CI, 1.20-3.33], P=0.008). Bleeding event rates were low overall (23 of 567 [4.1%]) and did not differ among the metabolizer groups. CONCLUSIONS: Black patients with CYP2C19 intermediate and poor metabolizer phenotypes who are treated with clopidogrel exhibit increased risk of adverse cardiovascular outcomes after PCI in a real-world clinical setting. Bleeding outcomes should be interpreted cautiously. Prospective studies are needed to determine whether genotype-guided use of prasugrel or ticagrelor in intermediate and poor metabolizers improves outcomes in Black patients undergoing PCI.

Acute pharmacodynamic responses to sitagliptin: Drug-induced increase in early insulin secretion in oral glucose tolerance test.

DPP4 inhibitors are widely prescribed as treatments for type 2 diabetes. Because drug responses vary among individuals, we initiated investigations to identify genetic variants associated with the magnitude of drug responses. Sitagliptin (100 mg) was administered to 47 healthy volunteers. Several endpoints were measured to assess clinically relevant responses - including the effect of sitagliptin on glucose and insulin levels during an oral glucose tolerance test (OGTT). This pilot study confirmed that sitagliptin (100 mg) decreased the area under the curve for glucose during an OGTT (p = 0.0003). Furthermore, sitagliptin promoted insulin secretion during the early portion of the OGTT as reflected by an increase in the ratio of plasma insulin at 30 min divided by plasma insulin at 60 min (T30:T60) from mean ± SEM 0.87 ± 0.05 to 1.62 ± 0.36 mU/L (p = 0.04). The magnitude of sitagliptin's effect on insulin secretion (as judged by the increase in the T30:T60 ratio for insulin) was correlated with the magnitude of sitagliptin-induced increase in the area under the curve for intact plasma GLP1 levels during the first hour of the OGTT. This study confirmed previously reported sex differences in glucose and insulin levels during an OGTT. Specifically, females exhibited higher levels of glucose and insulin at the 90-180 min time points. However, we did not detect significant sex-associated differences in the magnitude of sitagliptin-induced changes in T30:T60 ratios for either glucose or insulin. In conclusion, T30:T60 ratios for insulin and glucose during an OGTT provide useful indices to assess pharmacodynamic responses to DPP4 inhibitors.

Effectiveness of Clopidogrel vs Alternative P2Y12 Inhibitors Based on the ABCD-GENE Score.

BACKGROUND: An ABCD-GENE (age, body mass index, chronic kidney disease, diabetes, and CYP2C19 genetic variants) score ≥10 predicts reduced clopidogrel effectiveness, but its association with response to alternative therapy remains unclear. OBJECTIVES: The aim of this study was to evaluate the association between ABCD-GENE score and the effectiveness of clopidogrel vs alternative P2Y12 inhibitor (prasugrel or ticagrelor) therapy after percutaneous coronary intervention (PCI). METHODS: A total of 4,335 patients who underwent PCI, CYP2C19 genotyping, and P2Y12 inhibitor treatment were included. The primary outcome was major atherothrombotic events (MAE) within 1 year after PCI. Cox regression was performed to assess event risk in clopidogrel-treated (reference) vs alternatively treated patients, with stabilized inverse probability weights derived from exposure propensity scores after stratifying by ABCD-GENE score and further by CYP2C19 loss-of-function (LOF) genotype. RESULTS: Among patients with scores <10 (n = 3,200), MAE was not different with alternative therapy vs clopidogrel (weighted HR: 0.89; 95% CI: 0.65-1.22; P = 0.475). The risk for MAE also did not significantly differ by treatment among patients with scores ≥10 (n = 1,135; weighted HR: 0.75; 95% CI: 0.51-1.11; P = 0.155). Among CYP2C19 LOF allele carriers, MAE risk appeared lower with alternative therapy in both the group with scores <10 (weighted HR: 0.50; 95% CI: 0.25-1.01; P = 0.052) and the group with scores ≥10 (weighted HR: 0.48; 95% CI: 0.29-0.80; P = 0.004), while there was no difference in the group with scores <10 and no LOF alleles (weighted HR: 1.03; 95% CI: 0.70-1.51; P = 0.885). CONCLUSIONS: These data support the use of alternative therapy over clopidogrel in CYP2C19 LOF allele carriers after PCI, regardless of ABCD-GENE score, while clopidogrel is as effective as alternative therapy in non-LOF patients with scores <10.

Critical Role for 24-Hydroxylation in Homeostatic Regulation of Vitamin D Metabolism.

CONTEXT: The body has evolved homeostatic mechanisms to maintain free levels of Ca+2 and 1,25-dihydroxyvitamin D [1,25(OH)2D] within narrow physiological ranges. Clinical guidelines emphasize important contributions of PTH in maintaining this homeostasis. OBJECTIVE: To investigate mechanisms of homeostatic regulation of vitamin D (VitD) metabolism and to apply mechanistic insights to improve clinical assessment of VitD status. DESIGN: Crossover clinical trial studying participants before and after VitD3-supplementation. SETTING: Community. PARTICIPANTS: 11 otherwise healthy individuals with VitD-deficiency (25-hydroxyvitamin D [25(OH)D] ≤20 ng/mL). INTERVENTIONS: VitD3-supplements (50,000 IU once or twice a week depending on BMI, for 4-6 weeks) were administered to achieve 25(OH)D≥30 ng/mL. RESULTS: VitD3-supplementation significantly increased mean 25(OH)D by 2.7-fold and 24,25-dihydroxyvitamin D [24,25(OH)2D] by 4.3-fold. In contrast, mean levels of PTH, FGF23, and 1,25(OH)2D did not change. Mathematical modeling suggested that 24-hydroxylase activity was maximal for 25(OH)D≥50 ng/mL and achieved a minimum (∼90% suppression) with 25(OH)D<10-20 ng/mL. The 1,25(OH)2D/24,25(OH)2D ratio better predicted modeled 24-hydroxylase activity (h) (ρ=-0.85; p=0.001) compared to total plasma 25(OH)D (ρ=0.51; p=0.01) and the 24,25(OH)2D/25(OH)D ratio (ρ=0.37; p=0.3). CONCLUSIONS: Suppression of 24-hydroxylase provides a first line of defense against symptomatic VitD-deficiency by decreasing metabolic clearance of 1,25(OH)2D. The 1,25(OH)2D/24,25(OH)2D ratio provides a useful index of VitD status since it incorporates 24,25(OH)2D levels and therefore, provides insight into 24-hydroxylase activity. When VitD availability is limited, this suppresses 24-hydroxylase activity - thereby decreasing the level of 24,25(OH)2D and increasing the 1,25(OH)2D/24,25(OH)2D ratio. Thus, an increased 1,25(OH)2D/24,25(OH)2D ratio signifies triggering of homeostatic regulation, which occurs at early stages of VitD-deficiency.

Vitamin D Deficiency Increases Vulnerability to Canagliflozin-induced Adverse Effects on 1,25-Dihydroxyvitamin D and PTH.

CONTEXT: Canagliflozin has been reported to increase the risk of bone fracture-possibly mediated by decreasing 1,25-dihydroxyvitamin D (1,25(OH)2D) and increasing parathyroid hormone (PTH). OBJECTIVE: This work investigated whether baseline vitamin D (VitD) deficiency renders individuals vulnerable to this adverse effect and whether VitD3 supplementation is protective. METHODS: This community-based, outpatient study had a paired design comparing individual participants before and after VitD3 supplementation. Eleven VitD-deficient (25-hydroxyvitamin D [25(OH)D] ≤ 20 ng/mL) individuals were recruited from the Amish population in Lancaster, Pennsylvania. Participants underwent 2 canagliflozin challenge protocols (300 mg daily for 5 days): the first before and the second after VitD3 supplementation. In the VitD3 supplementation protocol, participants received VitD3 supplementation (50 000 IU once or twice a week depending on body mass index for 4-6 weeks) to achieve 25(OH)D of 30 ng/mL or greater. Two coprimary end points were identified: effects of VitD3 supplementation on canagliflozin-induced changes in 1,25(OH)2D and PTH. Secondary end points included effects of VitD3 supplementation on baseline levels of VitD metabolites and PTH. RESULTS: VitD3 supplementation increased mean 25(OH)D from 16.5 ± 1.6 to 44.3 ± 5.5 ng/mL (P = .0006) and 24,25-dihydroxyvitamin D (24,25(OH)2D) from 1.0 ± 0.1 to 4.3 ± 0.6 ng/mL (P = .0002). Mean 1,25(OH)2D and PTH were unchanged. VitD3 supplementation decreased the magnitude of canagliflozin-induced changes in 1,25(OH)2D (from -31.3%±4.7% to -9.3%±8.3%; P = .04) and PTH (from +36.2%±6.2% to +9.7%±3.7%; P = .005). CONCLUSION: VitD deficiency rendered individuals more vulnerable to adverse effects of canagliflozin on biomarkers associated with bone health. VitD3 supplementation was protective against canagliflozin's short-term adverse effects on 1,25(OH)2D and PTH.

Critical Role for 24-Hydroxylation in Homeostatic Regulation of Vitamin D Metabolism.

Context: The body has evolved homeostatic mechanisms to maintain free levels of Ca+2 and 1,25-dihydroxyvitamin D [1,25(OH)2D] within narrow physiological ranges. Clinical guidelines emphasize important contributions of PTH in maintaining this homeostasis. Objective: To investigate mechanisms of homeostatic regulation of vitamin D (VitD) metabolism and to apply mechanistic insights to improve clinical assessment of VitD status. Design: Crossover clinical trial studying participants before and after VitD3-supplementation. Setting: Community. Participants: 11 otherwise healthy individuals with VitD-deficiency (25-hydroxyvitamin D [25(OH)D] ≤20 ng/mL). Interventions: VitD3-supplements (50,000 IU once or twice a week depending on BMI, for 4-6 weeks) were administered to achieve 25(OH)D≥30 ng/mL. Results: VitD3-supplementation significantly increased mean 25(OH)D by 2.7-fold and 24,25-dihydroxyvitamin D [24,25(OH)2D] by 4.3-fold. In contrast, mean levels of PTH, FGF23, and 1,25(OH)2D did not change. Mathematical modeling suggested that 24-hydroxylase activity was maximal for 25(OH)D≥50 ng/mL and achieved a minimum (~90% suppression) with 25(OH)D<10-20 ng/mL. The 1,25(OH)2D/24,25(OH)2D ratio better predicted modeled 24-hydroxylase activity (h) (ρ=-0.85; p=0.001) compared to total plasma 25(OH)D (ρ=0.51; p=0.01) and the 24,25(OH)2D/25(OH)D ratio (ρ=0.37; p=0.3). Conclusions: Suppression of 24-hydroxylase provides a first line of defense against symptomatic VitD-deficiency by decreasing metabolic clearance of 1,25(OH)2D. The 1,25(OH)2D/24,25(OH)2D ratio provides a useful index of VitD status since it incorporates 24,25(OH)2D levels and therefore, provides insight into 24-hydroxylase activity. When VitD availability is limited, this suppresses 24-hydroxylase activity - thereby decreasing the level of 24,25(OH)2D and increasing the 1,25(OH)2D/24,25(OH)2D ratio. Thus, an increased 1,25(OH)2D/24,25(OH)2D ratio signifies triggering of homeostatic regulation, which occurs at early stages of VitD-deficiency.

Acute pharmacodynamic responses to sitagliptin: Drug-induced increase in early insulin secretion in oral glucose tolerance test.

Aim: DPP4 inhibitors are widely prescribed as treatments for type 2 diabetes. Because drug responses vary among individuals, we initiated investigations to identify genetic variants associated with the magnitude of drug responses. Methods: Sitagliptin (100 mg) was administered to 47 healthy volunteers. Several endpoints were measured to assess clinically relevant responses - including the effect of sitagliptin on glucose and insulin levels during an oral glucose tolerance test (OGTT). Results: This pilot study confirmed that sitagliptin (100 mg) decreased the area under the curve for glucose during an OGTT (p=0.0003). Furthermore, sitagliptin promoted insulin secretion during the early portion of the OGTT as reflected by an increase in the ratio of plasma insulin at 30 min divided by plasma insulin at 60 min (T30:T60) from 0.87+/-0.05 to 1.62+/-0.36 mU/L (p=0.04). The magnitude of sitagliptin's effect on insulin secretion (as judged by the increase in the T30:T60 ratio for insulin) was correlated with the magnitude of sitagliptin-induced increase in the area under the curve for intact plasma GLP1 levels during the first hour of the OGTT. This study confirmed previously reported sex differences in glucose and insulin levels during an OGTT. Specifically, females exhibited higher levels of glucose and insulin at the 90-180 min time points. However, we did not detect significant sex-associated differences in the magnitude of sitagliptin-induced changes in T30:T60 ratios for either glucose or insulin. Conclusions: T30:T60 ratios for insulin and glucose during an OGTT provide useful indices to assess pharmacodynamic responses to DPP4 inhibitors.

Pharmacogenetics of sodium-glucose co-transporter-2 inhibitors: Validation of a sex-agnostic pharmacodynamic biomarker.

AIM: To validate pharmacodynamic responses to sodium-glucose co-transporter-2 (SGLT2) inhibitors and test for association with genetic variants in SLC5A4, SLC5A9, and SLC2A9. METHODS: Canagliflozin (300 mg), a SGLT2 inhibitor, was administered to 30 healthy volunteers. Several endpoints were measured to assess clinically relevant responses, including drug-induced increases in urinary excretion of glucose, sodium and uric acid. RESULTS: This pilot study confirmed that canagliflozin (300 mg) triggered acute changes in mean levels of several biomarkers: fasting plasma glucose (-4.1 mg/dL; P = 6 × 10-5 ), serum creatinine (+0.05 mg/dL; P = 8 × 10-4 ) and serum uric acid (-0.90 mg/dL; P = 5 × 10-10 ). The effects of sex on glucosuria depended upon how data were normalized. Whereas males' responses were ~60% greater when data were normalized to body surface area, males and females exhibited similar responses when glucosuria was expressed as grams of urinary glucose per gram-creatinine. The magnitude of glucosuria was not significantly correlated with fasting plasma glucose, estimated glomerular filtration rate or age in those healthy individuals without diabetes with an estimated glomerular filtration rate of more than 60 mL/min/1.73m2 . CONCLUSIONS: Normalizing data relative to creatinine excretion will facilitate including data from males and females in a single analysis. Furthermore, because our ongoing pharmacogenomic study (NCT02891954) is conducted in healthy individuals, this will facilitate detection of genetic associations with limited confounding by other factors such as HbA1c and renal function.

Familial Hyperlipidemia Caused by Apolipoprotein B Mutation in the Pediatric Amish Population: A Mini Review.

Familial Hypercholesterolemia (FH) is an autosomal dominant genetic disorder that causes increased low density lipoprotein cholesterol (LDL-C) levels and a higher risk of premature atherosclerosis and cardiovascular disease (CVD). Common causes of FH include inherited genetic mutations in the LDLR, APOB, and PCSK9 genes. LDLR, APOB, and PCSK9 mutations account for 79%, 5%, and <1% of cases of FH respectively. Apolipoprotein B (ApoB) is the necessary atherogenic lipoprotein which can serve as a determinant of cardiovascular disease including hypercholesterolemia. A founder variant in Apolipoprotein B (APOB p.R3527Q) causes FH and is found in 12% of the Pennsylvania Amish population. This article provides an overview of ApoB metabolism and clinical manifestations associated with APOB mutations. An understanding of the clinical manifestations caused by APOB p.R3527Q can be beneficial for the clinical diagnosis and treatment of FH in the Amish. Based on previous studies, changes in LDL cholesterol (LDL-C), LDL particles (LDL-P), small dense LDL particles, and ApoB levels can be seen among these patients putting them at an increased risk for atherosclerotic issues, vascular hardening, and changes in endothelial function, particularly among homozygous individuals.

Acute pharmacodynamic responses to exenatide: Drug-induced increases in insulin secretion and glucose effectiveness.

AIM: Glucagon-like peptide-1 receptor agonists provide multiple benefits to patients with type 2 diabetes, including improved glycaemic control, weight loss and decreased risk of major adverse cardiovascular events. Because drug responses vary among individuals, we initiated investigations to identify genetic variants associated with the magnitude of drug responses. METHODS: Exenatide (5 µg, subcutaneously) or saline (0.2 ml, subcutaneously) was administered to 62 healthy volunteers. Frequently sampled intravenous glucose tolerance tests were conducted to assess the impact of exenatide on insulin secretion and insulin action. This pilot study was a crossover design in which participants received exenatide and saline in random order. RESULTS: Exenatide increased first phase insulin secretion 1.9-fold (p = 1.9 × 10-9 ) and accelerated the rate of glucose disappearance 2.4-fold (p = 2 × 10-10 ). Minimal model analysis showed that exenatide increased glucose effectiveness (Sg ) by 32% (p = .0008) but did not significantly affect insulin sensitivity (Si ). The exenatide-induced increase in insulin secretion made the largest contribution to interindividual variation in exenatide-induced acceleration of glucose disappearance while interindividual variation in the drug effect on Sg contributed to a lesser extent (ß = 0.58 or 0.27, respectively). CONCLUSIONS: This pilot study provides validation for the value of a frequently sampled intravenous glucose tolerance test (including minimal model analysis) to provide primary data for our ongoing pharmacogenomic study of pharmacodynamic effects of semaglutide (NCT05071898). Three endpoints provide quantitative assessments of the effects of glucagon-like peptide-1 receptor agonists on glucose metabolism: first phase insulin secretion, glucose disappearance rates and glucose effectiveness.

Vitamin D deficiency increases vulnerability to canagliflozin-induced adverse effects on 1,25-dihydroxyvitamin D and PTH.

Context. Canagliflozin has been reported to increase the risk of bone fracture - possibly mediated by decreasing 1,25-dihydroxyvitamin D [1,25(OH) 2 D] and increasing PTH. Objective. To investigate whether baseline vitamin D (VitD) deficiency renders individuals vulnerable to this adverse effect and whether VitD3 supplementation is protective. Design. This study had a paired design comparing individual participants before and after VitD3 supplementation. Setting. Community-based outpatient. Patients. 11 VitD deficient (25-hydroxyvitamin D [25(OH)D] ≤ 20 ng/mL) individuals recruited from the Amish population in Lancaster PA. Interventions. Participants underwent two canagliflozin challenge protocols (300 mg daily for five days): the first before and the second after VitD3 supplementation. In the VitD3 supplementation protocol, participants received VitD3 supplementation (50,000 IU once or twice a week depending on BMI for 4-6 weeks) to achieve 25(OH)D ≥ 30 ng/mL. Main Outcome Measures. Two co-primary endpoints were identified: effects of VitD3 supplementation on canagliflozin-induced changes in 1,25(OH) 2 D and PTH. Secondary endpoints included effects of VitD3 supplementation on baseline levels of VitD metabolites and PTH. Results. VitD3 supplementation increased mean 25(OH)D from 16.5±1.6 to 44.3±5.5 ng/mL (p=0.0006) and 24,25-dihydroxyvitamin D [24,25(OH) 2 D] from 1.0±0.1 to 4.3±0.6 ng/mL (p=0.0002). Mean 1,25(OH) 2 D and PTH were unchanged. VitD3 supplementation decreased the magnitude of canagliflozin-induced changes in 1,25(OH) 2 D (from -31.3%±4.7% to -9.3%±8.3%; p=0.04) and PTH (from +36.2%±6.2% to +9.7%±3.7%; p=0.005). Conclusions. VitD deficiency rendered individuals more vulnerable to adverse effects of canagliflozin on biomarkers associated with bone health. VitD3 supplementation was protective against canagliflozin's short-term adverse effects on 1,25(OH) 2 D and PTH.

Acute pharmacodynamic responses to exenatide: Drug-induced increases in insulin secretion and glucose effectiveness.

Background: GLP1R agonists provide multiple benefits to patients with type 2 diabetes - including improved glycemic control, weight loss, and decreased risk of major adverse cardiovascular events. Because drug responses vary among individuals, we initiated investigations to identify genetic variants associated with the magnitude of drug responses. Methods: Exenatide (5 µg, sc) or saline (0.2 mL, sc) was administered to 62 healthy volunteers. Frequently sampled intravenous glucose tolerance tests were conducted to assess the impact of exenatide on insulin secretion and insulin action. This pilot study was designed as a crossover study in which participants received exenatide and saline in random order. Results: Exenatide increased first phase insulin secretion 1.9-fold (p=1.9×10 -9 ) and accelerated the rate of glucose disappearance 2.4-fold (p=2×10 -10 ). Minimal model analysis demonstrated that exenatide increased glucose effectiveness (S g ) by 32% (p=0.0008) but did not significantly affect insulin sensitivity (S i ). The exenatide-induced increase in insulin secretion made the largest contribution to inter-individual variation in exenatide-induced acceleration of glucose disappearance while inter-individual variation in the drug effect on S g contributed to a lesser extent (ß=0.58 or 0.27, respectively). Conclusions: This pilot study provides validation for the value of an FSIGT (including minimal model analysis) to provide primary data for our ongoing pharmacogenomic study of pharmacodynamic effects of semaglutide ( NCT05071898 ). Three endpoints provide quantitative assessments of GLP1R agonists' effects on glucose metabolism: first phase insulin secretion, glucose disappearance rates, and glucose effectiveness. Registration: NCT02462421 (clinicaltrials.gov). Funding: American Diabetes Association (1-16-ICTS-112); National Institute of Diabetes and Digestive and Kidney Disease (R01DK130238, T32DK098107, P30DK072488).

Pharmacogenetics of SGLT2 Inhibitors: Validation of a sex-agnostic pharmacodynamic biomarker.

Aim: SGLT2 inhibitors provide multiple benefits to patients with type 2 diabetes - including improved glycemic control and decreased risks of cardiorenal disease. Because drug responses vary among individuals, we initiated investigations to identify genetic variants associated with the magnitude of drug responses. Methods: Canagliflozin (300 mg) was administered to 30 healthy volunteers. Several endpoints were measured to assess clinically relevant responses - including drug-induced increases in urinary excretion of glucose, sodium, and uric acid. Results: This pilot study confirmed that canagliflozin (300 mg) triggered acute changes in mean levels of several biomarkers: fasting plasma glucose (-4.1 mg/dL; p=6x10), serum creatinine (+0.05 mg/dL; p=8×10 -4 ), and serum uric acid (-0.90 mg/dL; p=5×10 -10 ). The effects of sex on glucosuria depended upon how data were normalized. Whereas males' responses were ∼60% greater when data were normalized to body surface area, males and females exhibited similar responses when glucosuria was expressed as grams of urinary glucose per gram-creatinine. The magnitude of glucosuria was not significantly correlated with fasting plasma glucose, estimated GFR, or age in these healthy non-diabetic individuals with estimated GFR>60 mL/min/1.73m 2 . Conclusions: Normalizing data relative to creatinine excretion will facilitate including data from males and females in a single analysis. Furthermore, because our ongoing pharmacogenomic study ( NCT02891954 ) is conducted in healthy individuals, this will facilitate detection of genetic associations with limited confounding by other factors such as age and renal function. Registration: NCT02462421 ( clinicaltrials.gov ). Funding: Research grants from the National Institute of Diabetes and Digestive and Kidney Diseases: R21DK105401, R01DK108942, T32DK098107, and P30DK072488.

Evaluation of Potential Racial Disparities in CYP2C19-Guided P2Y12 Inhibitor Prescribing After Percutaneous Coronary Intervention.

Black patients suffer worse outcomes after percutaneous coronary intervention (PCI) than White patients. Inequities in antiplatelet prescribing may contribute to this health disparity. We compared P2Y12 inhibitor prescribing by race following CYP2C19 genotyping to guide antiplatelet therapy selection after PCI. Patients from 9 sites that performed clinical CYP2C19 genotyping after PCI were included. Alternative therapy (e.g., prasugrel or ticagrelor) was recommended for CYP2C19 no-function allele carriers, in whom clopidogrel is predicted to be less effective. The primary outcome was choice of P2Y12 inhibitor (clopidogrel vs. alternative therapy) based on genotype. Of 3,342 patients included, 2,448 (73%) were White, and 659 (20%) were Black. More Black than White patients had a no-function allele (34.3% vs. 29.7%, P = 0.024). At hospital discharge following PCI, 44.2% of Black and 44.0% of White no-function allele carriers were prescribed alternative therapy. At the time of the last follow-up within 12 months, numerically fewer Black (51.8%) than White (56.7%) no-function allele carriers were prescribed alternative therapy (P = 0.190). However, the difference was not significant after accounting for other factors associated with P2Y12 inhibitor selection (odds ratio 0.79, 95% confidence interval 0.58-1.08). Alternative therapy use did not differ between Black (14.3%) and White (16.7%) patients without a no-function allele (P = 0.232). Among real-world patients who received CYP2C19 testing after PCI, P2Y12 inhibitor prescribing rates did not differ between Black and White patients. Our data suggest an absence of racial disparity in genotype-guided antiplatelet prescribing among patients receiving CYP2C19 testing.

Excessive platelet inhibition following Pipeline embolization of intracranial aneurysms.

BACKGROUND: High levels of platelet inhibition have been associated with hemorrhagic complications following Pipeline embolization of intracranial aneurysms. We therefore titrate clopidogrel dosing to maintain a moderate level of platelet inhibition using the VerifyNow P2Y12 assay. However, many patients demonstrate dramatic increases in platelet inhibition following treatment despite being on a consistent antiplatelet regimen. We therefore elected to explore the incidence of this phenomenon and possible predisposing factors. METHODS: All successful Pipeline aneurysm treatments performed at our institution from 2011 to 2019 with moderate procedure-day platelet inhibition levels as indicated by a VerifyNow PRU of 60-235 were included. Patients who received glycoprotein IIb/IIIa inhibitors and those treated for ruptured/symptomatic lesions were excluded. The incidence of excessive platelet inhibition defined by a PRU<60 within 8 weeks of treatment was noted. Multivariable logistic regression was performed to determined independent predictors of the phenomenon. RESULTS: Some 190 treatments were performed in 178 qualifying patients. A post-procedure PRU <60 occurred following 79% of treatments, documented on average after 8.5 (range 1-47) days. A higher procedure day hematocrit level (P=0.003, OR 1.09, 95% CI 1.029 to 1.152) was an independent predictor of reaching a PRU <60, while intra-procedural midazolam exposure (P=0.044, OR 0.44, 95% CI 0.201 to 0.980) and a higher procedure-day PRU (P=0.047, OR 0.99, 95% CI 0.982 to 1.000) were associated with a reduced odds. Time-since-procedure and hematocrit levels were associated with excessive platelet inhibition when excluding patients who initially demonstrated hyperresponse. CONCLUSION: Elevations in platelet inhibition were frequently observed following flow diversion with Pipeline.

Whole genome sequence analysis of apparent treatment resistant hypertension status in participants from the Trans-Omics for Precision Medicine program.

Introduction: Apparent treatment-resistant hypertension (aTRH) is characterized by the use of four or more antihypertensive (AHT) classes to achieve blood pressure (BP) control. In the current study, we conducted single-variant and gene-based analyses of aTRH among individuals from 12 Trans-Omics for Precision Medicine cohorts with whole-genome sequencing data. Methods: Cases were defined as individuals treated for hypertension (HTN) taking three different AHT classes, with average systolic BP ≥ 140 or diastolic BP ≥ 90 mmHg, or four or more medications regardless of BP (n = 1,705). A normotensive control group was defined as individuals with BP < 140/90 mmHg (n = 22,079), not on AHT medication. A second control group comprised individuals who were treatment responsive on one AHT medication with BP < 140/ 90 mmHg (n = 5,424). Logistic regression with kinship adjustment using the Scalable and Accurate Implementation of Generalized mixed models (SAIGE) was performed, adjusting for age, sex, and genetic ancestry. We assessed variants using SKAT-O in rare-variant analyses. Single-variant and gene-based tests were conducted in a pooled multi-ethnicity stratum, as well as self-reported ethnic/racial strata (European and African American). Results: One variant in the known HTN locus, KCNK3, was a top finding in the multi-ethnic analysis (p = 8.23E-07) for the normotensive control group [rs12476527, odds ratio (95% confidence interval) = 0.80 (0.74-0.88)]. This variant was replicated in the Vanderbilt University Medical Center's DNA repository data. Aggregate gene-based signals included the genes AGTPBP, MYL4, PDCD4, BBS9, ERG, and IER3. Discussion: Additional work validating these loci in larger, more diverse populations, is warranted to determine whether these regions influence the pathobiology of aTRH.