Pharmacogenomic study of heart failure and candesartan response from the CHARM programme.

AIMS: The Candesartan in Heart failure Assessment of Reduction in Mortality and morbidity (CHARM) programme consisted of three parallel, randomized, double-blind clinical trials comparing candesartan with placebo in patients with heart failure (HF) categorized according to left ventricular ejection fraction and tolerability to an angiotensin-converting enzyme inhibitor. We conducted a pharmacogenomic study of the CHARM trials with the objective of identifying genetic predictors of HF progression and of the efficacy and safety of treatment with candesartan. METHODS: We performed genome-wide association studies in 2727 patients of European ancestry from CHARM-Overall and stratified by CHARM study according to preserved and reduced ejection fraction and according to assignment to the interventional treatment with candesartan. We tested genetic association with the composite endpoint of cardiovascular death or hospitalization for heart failure for drug efficacy in candesartan-treated patients and for HF progression using patients from both candesartan and placebo arms. The safety endpoints for response to candesartan were hyperkalaemia, renal dysfunction, hypotension, and change in systolic blood pressure between baseline and 6 weeks of treatment. To support our observations, we conducted a genome-wide gene-level collapsing analysis from whole-exome sequencing data with the composite cardiovascular endpoint. RESULTS: We found that the A allele (14% allele frequency) of the genetic variant rs66886237 at 8p21.3 near the gene GFRA2 was associated with the composite cardiovascular endpoint in 1029 HF patients with preserved ejection fraction from the CHARM-Preserved study (hazard ratio: 1.91, 95% confidence interval: 1.55-2.35; P = 1.7 × 10-9 ). The association was independent of candesartan treatment, and the genetic variant was not associated with the cardiovascular endpoint in patients with reduced ejection fraction. None of the genome-wide association studies for candesartan safety or efficacy conducted in patients treated with candesartan passed the significance threshold. We found no significant association from the gene-level collapsing analysis. CONCLUSIONS: We have identified a candidate genetic variant potentially predictive of the progression of heart failure in patients with preserved ejection fraction. The findings require further replication, and we cannot exclude the possibility that the results may be chance findings.

Harmony Outcomes: A randomized, double-blind, placebo-controlled trial of the effect of albiglutide on major cardiovascular events in patients with type 2 diabetes mellitus-Rationale, design, and baseline characteristics.

BACKGROUND: Albiglutide is a long-acting glucagon-like peptide-1 receptor agonist that improves glycemic control in patients with type 2 diabetes mellitus (T2DM). Harmony Outcomes is a randomized, double-blind, placebo-controlled trial of the effect of albiglutide on major adverse cardiovascular (CV) events in patients with T2DM and established CV disease. METHODS: The trial was designed to recruit 9,400 patients aged ≥40 years with T2DM, prior atherosclerotic CV disease, and suboptimal glycemic control. Participants were assigned in a 1:1 ratio to albiglutide 30 mg (potentially increasing to 50 mg) or matching placebo administered once weekly by subcutaneous injection. The trial will continue until ≥611 confirmed primary outcome events (CV death, myocardial infarction, or stroke) occur over a median follow-up of at least 1.5 years. RESULTS: A total of 9,463 patients were enrolled at 611 sites in 28 countries between July 2015 and December 2016. The mean age was 64.1 years; duration of T2DM, 13.8 years; and glycated hemoglobin, 8.7%. The percentage of patients with prior coronary artery disease was 70.5%; peripheral arterial disease, 25.0%; stroke, 17.7%; heart failure, 20.2%; and chronic kidney disease, 22.6%. CONCLUSIONS: Harmony Outcomes will assess the CV safety of albiglutide in patients with T2DM and CV disease. Trials of other agents in the glucagon-like peptide-1 receptor agonist class have shown CV benefit for only some of these medications, possibly due to differences in trial design or instead due to differences in drug structure or metabolism. Harmony Outcomes will provide information critical to our understanding of this heterogenous class of glucose-lowering agents.

Genetic effects in the leukotriene biosynthesis pathway and association with atherosclerosis.

Leukotrienes are arachidonic acid derivatives long known for their inflammatory properties and their involvement with a number of human diseases, most particularly asthma. Recently, leukotriene-based inflammation has also been shown to play an important role in atherosclerosis: ALOX5AP and LTA4H, both genes in the leukotriene biosynthesis pathway, have individually been shown to be associated with various cardiovascular disease (CVD) phenotypes. To assess the role of the leukotriene pathway in CVD pathogenesis, we performed genetic association studies of ALOX5AP and LTA4H in a family based study of early onset coronary artery disease (EOCAD) (GENECARD, 1,101 families) and in a non-familial dataset of EOCAD (CATHGEN, 656 cases and 405 controls). We found weak to moderate association between single nucleotide polymorphisms (SNPs) in ALOX5AP and LTA4H with EOCAD. The previously reported four-SNP haplotype (HapA) in ALOX5AP showed association with EOCAD in CATHGEN (P = 0.02), while controlling for age, race and CVD risk factors. HapK, the previously reported ten-SNP haplotype in LTA4H was associated with EOCAD in CATHGEN (P = 0.04). Another previously reported four-SNP haplotype in ALOX5AP (HapB) was not significant in our sample (P = 0.39). The overall lack of (or weak) association of single SNPs as compared with the haplotype results demonstrates the need for analyzing multiple SNPs within each gene in such studies. Interestingly, we detected an association of SNPs in ALOX5 (P < 0.05), the target of ALOX5AP, with CVD. Using a pathway-based approach, we also detected statistical evidence for interactions among ALOX5, ALOX5AP and LTA4H using RNA expression data from a collection of freshly harvested human aortas with varying degrees of atherosclerosis. The GENECARD families did not demonstrate evidence for linkage or association with ALOX5, ALOX5AP or LTA4H. Our results support a modest role for the leukotriene pathway in atherosclerosis pathogenesis, reveal important genomic interactions within the pathway, and suggest the importance of using pathway-based modeling for evaluating the genomics of atherosclerosis susceptibility.

ST resolution 1 hour after fibrinolysis for prediction of myocardial infarct size: insights from ASSENT 3.

Acute ST-segment elevation myocardial infarction requires prompt restoration of myocardial perfusion to salvage myocardium at risk of ischemic necrosis and improve clinical outcome. Early resolution of ST-segment elevation during the time after reperfusion has been associated with both these end points. From the ASsessment of the Safety and Efficacy of a New Thrombolytic regimen (ASSENT) 3 trial, 3,425 patients were analyzed to investigate whether the amount of ST-segment resolution, divided into 3 groups (complete, >70%; partial, 30% to 70%; and no resolution, <30%), in the first hour after initiation of therapy was a predictor of final infarct size, estimated by peak creatine kinase and Selvester QRS score on the discharge electrocardiogram. Complete compared with partial and no ST resolution resulted in significantly (p<0.001) smaller infarct sizes of 10.5%, 13.2%, and 15.0% of the left ventricle and significantly (p=0.001) fewer patients with peak creatine >5 times the upper reference level at 50.3%, 71.8%, and 76.3%, respectively. In conclusion, our findings supported previous smaller studies suggesting that early resolution of ST elevation, as a sign of early myocardial reperfusion, resulted in less myocardial damage and preservation of left ventricular function.

Time course of degradation of cardiac troponin I in patients with acute ST-elevation myocardial infarction: the ASSENT-2 troponin substudy.

Although measurement of troponin is widely used for diagnosing acute myocardial infarction (AMI), its diagnostic potential may be increased by a more complete characterization of its molecular appearance and degradation in the blood. The aim of this study was to define the time course of cardiac troponin I (cTnI) degradation in patients with acute ST-elevation myocardial infarction (STEMI). In the ASSENT-2 substudy, 26 males hospitalized with STEMI were randomized to 2 different thrombolytic drugs within 6 hours after onset of symptoms. Blood samples were obtained just before initiation of thrombolysis and at 30 minutes intervals (7 samples per patient). Western blot analysis was performed using anti-cTnI antibodies and compared with serum concentrations of cTnI. All patients exceeded the cTnI cutoff for AMI during the sampling period; at initiation of therapy, 23 had elevated cTnI values. All patients demonstrated 2 bands on immunoblot: intact cTnI and a single degradation product as early as 90 minutes after onset of symptoms. On subsequent samples, 15 of 26 patients showed multiple degradation products with up to 7 degradation bands. The appearance of fragments was correlated with higher levels of cTnI (P<0.001) and time to initiation of treatment (P=0.058). This study defines for the first time the initial time course of cTnI degradation in STEMI. Intact cTnI and a single degradation product were detectable on immunoblot as early as 90 minutes after onset of symptoms with further degradation after 165 minutes. Infarct size and time to initiation of treatment was the major determinant for degradation.