👤 Bruce A Pfeffer

In uveal melanoma (UM), the most common primary intraocular tumor, up to half of patients develop fatal metastases despite high local tumor control. Effective treatments for genetically high-risk tumors remain limited, largely due to challenges posed by cancer stem cells (CSCs) and the tumor microenvironment (TME), which sustain tumor progression and resistance. Our study evaluated stemness properties in UM tumor cells, focusing on Show less

Acute coronary syndrome (ACS) survivors have heightened risk for subsequent cardiovascular events. All baseline characteristics collected in both the Dal-Outcomes and Dal-GenE trials were considered as potential risk markers. A prediction index for subsequent fatal and non-fatal myocardial infarction (MI) following ACS was developed using Cox proportional hazards modeling on data from Dal-Outcomes placebo patients (n=7086). This prediction index was then applied in all Dal-GenE participants (n=5989) to determine whether the reduction in MI observed with dalcetrapib (versus placebo) in patients with the AA genotype at rs1967309 in the ADCY9 gene remained significant, independent of the other markers integrated into the prediction index. Of the 36 baseline variables considered as potential risk markers, 18 contributed to the prediction index with a Harrell's C-index of 0.72 (95% CI, 0.69-0.75) in Dal-Outcomes placebo patients. Prior history of coronary events, LDL-C, blood pressure, A1c, hs-CRP, smoking and age were contributors. The prediction index was strongly predictive when applied to the 5989 AA genotype patients from Dal-GenE, with a HR for MI of 1.92 (95%CI: 1.78-2.08) for each SD increase in score. When adjusting for the prediction index, the HR for dalcetrapib versus placebo was 0.77 (95% CI, 0.63-0.94) in Dal-GenE. Despite guideline directed therapy following ACS, history of prior coronary events and on-treatment LDL-C, A1c, hs-CRP and blood pressure remain determinants of future MI. In the Dal-GenE AA genotype patients, dalcetrapib reduced the rate of MI, independently of those variables. The Dal-GenE 2 trial is designed to confirm this pharmacogenetic hypothesis. Show less

In 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. dal-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). Dalcetrapib 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. Trial registration dal-GenE ClinicalTrials.gov Identifier: NCT02525939. Show less

The relationship between blood pressure and mortality in type 2 diabetes (T2DM) is controversial, with concern for increased risk associated with excessively lowered blood pressure. We evaluated whether prior cardiovascular disease (CVD) altered the relationship between baseline blood pressure and all-cause mortality in 5852 patients with T2DM and a recent acute coronary syndrome (ACS) who participated in the ELIXA (Evaluation of Lixisenatide in Acute Coronary Syndrome) trial. Risk of death was assessed in Cox models adjusted for age, sex, race, heart rate, BMI, smoking, diabetes duration, insulin use, HbA1c, eGFR, brain natriuretic peptide (BNP), urine albumin/creatinine ratio, treatment allocation and prior coronary revascularization. Although overall there was no significant association between systolic blood pressure (SBP) and mortality (hazard ratio per 10 mmHg lower SBP 1.05 (95% CI 0.99-1.12) P = 0.10), lower SBP was significantly associated with higher risk of death (hazard ratio per 10 mmHg lower SBP 1.13 (95% CI 1.04-1.22) P = 0.002) in 2325 patients with additional CVD (index ACS+ at least one of the following prior to randomization: myocardial infarction other than the index ACS, stroke or heart failure). In 3527 patients with only the index ACS no significant association was observed (hazard ratio per 10 mmHg lower SBP 0.95 (0.86-1.04) P = 0.26; P for interaction 0.005). The association between blood pressure and mortality was modified by additional CVD history in patients with type 2 diabetes and a recent coronary event. When blood pressures measured after an acute coronary event are used to assess the risk of death in patients with type 2 diabetes, the cardiovascular history needs to be taken into consideration. Trial registration ClinicalTrials.gov number NCT01147250, first posted June 22, 2010. Show less

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. Show less

Tissue accumulation of 7-dehydrocholesterol (7DHC) is a hallmark of Smith-Lemli-Opitz Syndrome (SLOS), a human inborn error of the cholesterol (CHOL) synthesis pathway. Retinal 7DHC-derived oxysterol formation occurs in the AY9944-induced rat model of SLOS, which exhibits a retinal degeneration characterized by selective loss of photoreceptors and associated functional deficits, Müller cell hypertrophy, and engorgement of the retinal pigment epithelium (RPE) with phagocytic inclusions. We evaluated the relative effects of four 7DHC-derived oxysterols on three retina-derived cell types in culture, with respect to changes in cellular morphology and viability. 661W (photoreceptor-derived) cells, rMC-1 (Müller glia-derived) cells, and normal diploid monkey RPE (mRPE) cells were incubated for 24 h with dose ranges of either 7-ketocholesterol (7kCHOL), 5,9-endoperoxy-cholest-7-en-3β,6α-diol (EPCD), 3β,5α-dihydroxycholest-7-en-6-one (DHCEO), or 4β-hydroxy-7-dehydrocholesterol (4HDHC); CHOL served as a negative control (same dose range), along with appropriate vehicle controls, while staurosporine (Stsp) was used as a positive cytotoxic control. For 661W cells, the rank order of oxysterol potency was: EPCD > 7kCHOL >> DHCEO > 4HDHC ≈ CHOL. EC50 values were higher for confluent vs. subconfluent cultures. 661W cells exhibited much higher sensitivity to EPCD and 7kCHOL than either rMC-1 or mRPE cells, with the latter being the most robust when challenged, either at confluence or in sub-confluent cultures. When tested on rMC-1 and mRPE cells, EPCD was again an order of magnitude more potent than 7kCHOL in compromising cellular viability. Hence, 7DHC-derived oxysterols elicit differential cytotoxicity that is dose-, cell type-, and cell density-dependent. These results are consistent with the observed progressive, photoreceptor-specific retinal degeneration in the rat SLOS model, and support the hypothesis that 7DHC-derived oxysterols are causally linked to that retinal degeneration as well as to SLOS. Show less