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AimsIn a retrospective analysis of dal-Outcomes, the effect of dalcetrapib on cardiovascular events was influenced by an adenylate cyclase type 9 (ADCY9) gene polymorphism. The dal-GenE study was conducted to test this pharmacogenetic hypothesis.Methods and resultsdal-GenE was a double-blind trial in patients with an acute coronary syndrome within 1-3 months and the AA genotype at variant rs1967309 in the ADCY9 gene. A total of 6147 patients were randomly assigned to receive dalcetrapib 600 mg or placebo daily. The primary endpoint was the time from randomization to first occurrence of cardiovascular death, resuscitated cardiac arrest, non-fatal myocardial infarction, or non-fatal stroke. After a median follow-up of 39.9 months, the primary endpoint occurred in 292 (9.5%) of 3071 patients in the dalcetrapib group and 327 (10.6%) of 3076 patients in the placebo group [hazard ratio 0.88; 95% confidence interval (CI) 0.75-1.03; P = 0.12]. The hazard ratios for the components of the primary endpoint were 0.79 (95% CI 0.65-0.96) for myocardial infarction, 0.92 (95% CI 0.64-1.33) for stroke, 1.21 (95% CI 0.91-1.60) for death from cardiovascular causes, and 2.33 (95% CI 0.60-9.02) for resuscitated cardiac arrest. In a pre-specified on-treatment sensitivity analysis, the primary endpoint event rate was 7.8% (236/3015) in the dalcetrapib group and 9.3% (282/3031) in the placebo group (hazard ratio 0.83; 95% CI 0.70-0.98).ConclusionDalcetrapib did not significantly reduce the risk of occurrence of the primary endpoint of ischaemic cardiovascular events at end of study. A new trial would be needed to test the pharmacogenetic hypothesis that dalcetrapib improves the prognosis of patients with the AA genotype.Clinical trial registrationTrial registration dal-GenE ClinicalTrials.gov Identifier: NCT02525939.

Following the neutral results of the dal-OUTCOMES trial, a genome-wide study identified the rs1967309 variant in the adenylate cyclase type 9 (ADCY9) gene on chromosome 16 as being associated with the risk of future cardiovascular events only in subjects taking dalcetrapib, a CETP (cholesterol ester transfer protein) modulator. Homozygotes for the minor A allele (AA) were protected from recurrent cardiovascular events when treated with dalcetrapib, while homozygotes for the major G allele (GG) had increased risk. Here, we present the current state of knowledge regarding the impact of rs1967309 in ADCY9 on clinical observations and biomarkers in dalcetrapib trials and the effects of mouse ADCY9 gene inactivation on cardiovascular physiology. Finally, we present our current model of the interaction between dalcetrapib and ADCY9 gene variants in the arterial wall macrophage, based on the intracellular role of CETP in the transfer of complex lipids from endoplasmic reticulum membranes to lipid droplets. Briefly, the concept is that dalcetrapib would inhibit CETP-mediated transfer of cholesteryl esters, resulting in a progressive inhibition of cholesteryl ester synthesis and free cholesterol accumulation in the endoplasmic reticulum. Reduced ADCY9 activity, by paradoxically leading to higher cyclic AMP levels and in turn increased cellular cholesterol efflux, could impart cardiovascular protection in rs1967309 AA patients. The ongoing dal-GenE trial recruited 6145 patients with the protective AA genotype and will provide a definitive answer to whether dalcetrapib will be protective in this population.

The objectives of precision medicine are to better match patient characteristics with the therapeutic intervention to optimize the chances of beneficial actions while reducing the exposure to unneeded adverse drug experiences. In a retrospective genome-wide association study of the overall neutral placebo-controlled dal-Outcomes trial, the effect of the cholesteryl ester transfer protein (CETP) modulator dalcetrapib on the composite of cardiovascular death, myocardial infarction or stroke was found to be influenced by a polymorphism in the adenylate cyclase type 9 (ADCY9) gene. Whereas patients with the AA genotype at position rs1967309 experienced fewer cardiovascular events with dalcetrapib, those with the GG genotype had an increased rate and the heterozygous AG genotype exhibited no difference from placebo. Measurements of cholesterol efflux and C-reactive protein (CRP) offered directionally supportive genotype-specific findings. In a separate, smaller, placebo-controlled trial, regression of ultrasonography-determined carotid intimal-medial thickness was only observed in dalcetrapib-treated patients with the AA genotype. Collectively, these observations led to the hypothesis that the cardiovascular effects of dalcetrapib may be pharmacogenetically determined, with a favorable benefit-risk ratio only for patients with this specific genotype. We describe below the design of dal-GenE, a precision medicine, placebo-controlled clinical outcome trial of dalcetrapib in patients with a recent acute myocardial infarction with the unique feature of selecting only those with the AA genotype at rs1967309 in the ADCY9 gene.

The new HMG-CoA reductase inhibitor, atorvastatin, appears to reduce elevated blood levels of triglycerides. Elevated triglyceride levels are associated with an increased risk of coronary artery disease. Researchers randomized 55 people with elevated triglycerides into one of four groups: groups that would take 5 milligrams (mg), 20 mg or 80 mg of atorvastatin and a group that would take a placebo. All of the volunteers were on a low-cholesterol diet. After two weeks, atorvastatin had lowered triglyceride levels from 26.5% to 45.8% on average, depending on the dose. Higher doses led to greater reductions. In addition, the drug lowered total cholesterol and LDL and VLDL cholesterol, all of which are risk factors for coronary artery disease when elevated. Ten percent of the people taking the drug experienced an adverse effect, which included headache, pain, diarrhea and flatulence. HMG-CoA reductase inhibitors are usually used to reduce elevated cholesterol levels.

Objective. - We followed the clinical course of four patients with type I hyperlipidemia from two kindreds who presented at an early age. Patients. - Two propositi presented with severe abdominal pain and bloody diarrhea at 8 and 10 weeks of age. They also exhibited delayed growth. We compared their course with that of two siblings (one sibling of each proband) who also have familial hyperchylomicronemia but were diagnosed and have subsequently shown normal growth. Main Results. - Although each sibling pair possesses the same lipoprotein lipase gene defect and resides in a similar environment, significant differences in stature are apparent. Conclusion. - Specific structural defects in the lipoprotein lipase gene alone do not define phenotypic presentation. However, severity of clinical presentation may influence future growth characteristics. (AJDC. 1993;147:60-62)