New oral protease-activated receptor 4 antagonist BMS-986120: tolerability, pharmacokinetics, pharmacodynamics, and gene variant effects in humans.

BMS-986120 is a novel first-in-class oral protease-activated receptor 4 (PAR4) antagonist exhibiting robust antithrombotic activity that has shown low bleeding risk in monkeys. We sought to assess pharmacokinetics, pharmacodynamics, and tolerability of BMS-986120 in healthy participants and platelet responses to BMS-986120 in participants carrying PAR4 A120T variants. Phase I, randomized, double-blind, placebo-controlled single-ascending-dose (SAD; N = 56) and multiple-ascending-dose (MAD; N = 32) studies were conducted. Exposure was approximately dose-proportional: maximum concentrations 27.3 and 1536 ng/mL, areas under the curve (AUC) to infinity of 164 and 15,603 h*ng/mL, and half-lives of 44.7 and 84.1 hours for 3.0 and 180 mg, respectively. The accumulation index suggested an ~2-fold AUC increase at steady state. Single doses of 75 and 180 mg BMS-986120 produced ≥80% inhibition of 12.5 µM PAR4 agonist peptide (AP)-induced platelet aggregation through at least 24 hours postdose, and doses ≥10 mg for ~7 days inhibited aggregation completely through 24 hours. No differences in PAR4-mediated platelet response were seen between AA120 versus TT120 PAR4 variants. In cells expressing A120 or T120 PAR4 proteins, no differences in half-maximal effective concentration in receptor activation by PAR4-AP were observed. BMS-986120 was well tolerated with dose-proportional pharmacokinetics and concentration-dependent pharmacodynamics in healthy participants over a wide dose range.ClinicalTrials.gov ID: NCT02208882.

Genetic and gene expression studies implicate renin and endothelin-1 in edema caused by peroxisome proliferator-activated receptor gamma agonists.

OBJECTIVE: Peroxisome proliferator-activated receptor gamma (PPARgamma) agonists can cause peripheral edema in susceptible individuals. To investigate the mechanistic basis underlying this adverse event, we performed a candidate gene analysis of patients enrolled in clinical trials of muraglitazar, an investigational PPARalpha/gamma dual agonist, and developed a cell culture-based gene expression assay and nonhuman primate model of edema to study the edemagenic properties of PPARgamma agonists. METHODS: A total of 213 single nucleotide polymorphisms (SNPs) in 63 genes were genotyped in 730 participants. Chi-square and logistic regression analyses were used to test for association with edema. Transcriptional responses to PPARgamma agonists were evaluated in Calu-6 cells using quantitative real-time PCR. Male Cynomolgus monkeys were treated with PPAR agonists and were evaluated for edema using MRI. RESULTS: SNPs in renin (rs2368564) and endothelin-1 (rs5370) were associated with reduced risk of edema (P=0.003 and P=0.028, respectively) and an SNP in beta1 adrenergic receptor (rs1801253) was associated with increased susceptibility to edema (P=0.034). Gene expression studies revealed that renin and endothelin-1 were regulated by PPARgamma in Calu-6 cells. A survey of 10 PPARgamma agonists further revealed that a compound's in vitro potency was correlated with its edemagenic potential leading to the prediction that one of three previously uncharacterized PPARgamma agonists would cause less edema. This prediction was validated in a nonhuman primate model of PPARgamma agonist-induced edema. CONCLUSION: Our results implicate a key role for renin and endothelin-1 in the edema caused by PPARgamma agonists and demonstrate how knowledge gained from pharmacogenetic studies can be applied in drug discovery.

Genotyping using the TaqMan assay.

The 5'-nuclease allelic discrimination assay, or TaqMan assay, is a PCR-based assay for genotyping single nucleotide polymorphisms (SNPs). The region flanking the SNP is amplified in the presence of two allele-specific fluorescent probes. The probes do not fluoresce in solution because of a quencher at the 3' end. The presence of two probes allows the detection of both alleles in a single tube. Moreover, because probes are included in the PCR, genotypes are determined without any post-PCR processing, a feature that is unavailable with most other genotyping methods. This unit describes probe and primer design and PCR conditions.

Frequency of CYP1A2 polymorphism in beagle dogs.

A single nucleotide polymorphism in the dog CYP1A2 gene causes these animals to be CYP1A2 deficient (i.e., lack functional CYP1A2 enzyme activity). Genotyping a colony of 79 dogs revealed 77% wild-type, 19% heterozygous, and 4% homozygous mutant animals. These genetic frequencies are significantly different from those previously reported and illustrate that different sources and populations of dogs can have dramatically different frequencies of this polymorphism.

Evaluation of the paraoxonases as candidate genes for stroke: Gln192Arg polymorphism in the paraoxonase 1 gene is associated with increased risk of stroke.

BACKGROUND AND PURPOSE: The paraoxonases are involved in protecting low-density lipoprotein (LDL) from lipid oxidation. Paraoxonase 1 (PON1) was implicated in susceptibility to coronary artery disease and stroke in previous studies. We evaluated, in a comprehensive way, all 3 paraoxonase genes for association with stroke observed in the Cholesterol and Recurrent Events (CARE) trial. METHODS: Over 2500 subjects enrolled in the CARE trial were genotyped for 14 single nucleotide polymorphisms, including 7 newly identified in this study, in the 3 paraoxonase genes. RESULTS: A glutamine (Gln)/arginine (Arg) polymorphism at amino acid residue 192 in PON1 was significantly associated with stroke (P=0.003 in multivariate analysis, including age, sex, LDL, hypertension, diabetes, smoking, and pravastatin treatment as covariates). The odds ratios were 2.28 (95% CI, 1.38 to 3.79) for Gln/Arg heterozygotes and 2.47 (95% CI, 1.18 to 5.19) for Arg/Arg homozygotes compared with Gln/Gln homozygotes. These results are consistent with 2 of 3 other published studies. In combined analysis of all 4 studies, the association between Gln192Arg SNP and stroke was highly significant (chi2(8df)=45.58, P<0.000001). Sequence analysis of the PON1 gene from seventy stroke cases revealed a novel nonsense mutation at codon 32 in one stroke case, which was not detected in over 2500 unaffected individuals. Polymorphisms in the PON2 and PON3 genes were not associated with stroke. CONCLUSIONS: These results suggest that Gln192Arg genotype is an important risk factor for stroke.