Erin A. Bohula

Ezetimibe Added to Statin Therapy after Acute Coronary Syndromes

BACKGROUND Statin therapy reduces low-density lipoprotein (LDL) cholesterol levels and the risk of cardiovascular events, but whether the addition of ezetimibe, a nonstatin drug that reduces intestinal cholesterol absorption, can reduce the rate of cardiovascular events further is not known. METHODS We conducted a double-blind, randomized trial involving 18,144 patients who had been hospitalized for an acute coronary syndrome within the preceding 10 days and had LDL cholesterol levels of 50 to 100 mg per deciliter (1.3 to 2.6 mmol per liter) if they were receiving lipid-lowering therapy or 50 to 125 mg per deciliter (1.3 to 3.2 mmol per liter) if they were not receiving lipid-lowering therapy. The combination of simvastatin (40 mg) and ezetimibe (10 mg) (simvastatin-ezetimibe) was compared with simvastatin (40 mg) and placebo (simvastatin monotherapy). The primary end point was a composite of cardiovascular death, nonfatal myocardial infarction, unstable angina requiring rehospitalization, coronary revascularization (≥30 days after randomization), or nonfatal stroke. The median follow-up was 6 years. RESULTS The median time-weighted average LDL cholesterol level during the study was 53.7 mg per deciliter (1.4 mmol per liter) in the simvastatin-ezetimibe group, as compared with 69.5 mg per deciliter (1.8 mmol per liter) in the simvastatin-monotherapy group (P<0.001). The Kaplan-Meier event rate for the primary end point at 7 years was 32.7% in the simvastatin-ezetimibe group, as compared with 34.7% in the simvastatin-monotherapy group (absolute risk difference, 2.0 percentage points; hazard ratio, 0.936; 95% confidence interval, 0.89 to 0.99; P=0.016). Rates of prespecified muscle, gallbladder, and hepatic adverse effects and cancer were similar in the two groups. CONCLUSIONS When added to statin therapy, ezetimibe resulted in incremental lowering of LDL cholesterol levels and improved cardiovascular outcomes. Moreover, lowering LDL cholesterol to levels below previous targets provided additional benefit. (Funded by Merck; IMPROVE-IT ClinicalTrials.gov number, NCT00202878.).

Downregulation of the type 1 insulin-like growth factor receptor in mouse melanoma cells is associated with enhanced radiosensitivity and impaired activation of Atm kinase

The type 1 insulin-like growth factor receptor (IGF1R) is required for growth, tumorigenicity and protection from apoptosis. IGF1R overexpression is associated with radioresistance in breast cancer. We used antisense (AS) RNA to downregulate IGF1R expression in mouse melanoma cells. Cells expressing AS-IGF1R transcripts were more radiosensitive in vitro and in vivo than controls. Also they showed reduced radiation-induced p53 accumulation and p53 serine 18 phosphorylation, and radioresistant DNA synthesis. These changes were reminiscent of the cellular phenotype of the human genetic disorder ataxia-telangiectasia (A-T), caused by mutations in the ATM gene. Cellular Atm protein levels were lower in AS-IGF1R-transfected cells than in control cells, although there was no difference in Atm expression at the transcriptional level. AS-IGF1R cells had detectable basal Atm kinase activity, but failed to induce kinase activity after irradiation. This suggests that IGF1R signalling can modulate the function of Atm, and supports the concept of targeted IGF1R downregulation as a potential treatment for malignant melanoma and other radioresistant tumours.

Achievement of Dual Low-Density Lipoprotein Cholesterol and High-Sensitivity C-Reactive Protein Targets More Frequent With the Addition of Ezetimibe to Simvastatin and Associated With Better Outcomes in IMPROVE-IT

Background— Statins lower low-density lipoprotein cholesterol (LDL-C) and high-sensitivity C-reactive protein (hs-CRP); addition of ezetimibe to statins further reduces LDL-C and hs-CRP. An analysis of the relationship between achieved LDL-C and hs-CRP targets and outcomes for simvastatin and ezetimibe/simvastatin was prespecified in Improved Reduction of Outcomes: Vytorin Efficacy International Trial (IMPROVE-IT). Methods and Results— The IMPROVE-IT trial randomly assigned 18 144 patients stabilized after acute coronary syndrome to simvastatin or ezetimibe/simvastatin. LDL-C and hs-CRP were measured at baseline and 1 month after randomization. Outcomes were assessed in those achieving one or both of the prespecified targets of LDL-C<70 mg/dL and hs-CRP<2 mg/L versus achieving neither target, adjusting for differences in baseline characteristics. An exploratory analysis examined targets of LDL-C<50 mg/dL and hs-CRP<1 mg/L. Patients meeting both targets at baseline, with no 1-month values, or with end points before 1 month were excluded. Of 15 179 patients, 39% achieved the dual LDL-C (<70 mg/dL) and hs-CRP (<2 mg/L) targets at 1 month, 14% met neither target, 14% met only the hs-CRP target, and 33% met only the LDL-C target. Those achieving dual targets had lower primary end point rates than those meeting neither target (cardiovascular death, major coronary event, or stroke; 38.9% versus 28.0%; adjusted hazard ratio, 0.73; 0.66–0.81; P<0.001). More patients treated with ezetimibe/simvastatin met dual targets than those treated with simvastatin alone (50% versus 29%, P<0.001). The association of dual-target attainment with improved outcomes was similar irrespective of treatment assignment (P-interaction=0.65). Similar findings were observed using the exploratory targets. Conclusions— Significantly more patients treated with ezetimibe/simvastatin met prespecified and exploratory dual LDL-C and hs-CRP targets than patients treated with simvastatin alone. Reaching both LDL-C and hs-CRP targets was associated with improved outcomes after multivariable adjustment. Clinical Trial Registration— URL: http://www.clinicaltrials.gov; Unique identifier: NCT00202878.

Asynchronous Cell Cycle and Asymmetric Vacuolar Inheritance in True Hyphae of Candida albicans

ABSTRACT Candida albicans forms unconstricted hyphae in serum-containing medium that are divided into discrete compartments. Time-lapse photomicroscopy, flow cytometry, and a novel three-dimensional imaging system were used to demonstrate that the kinetics and cell cycle events accompanying hyphal development were correlated with dynamic changes in vacuole morphology and the pattern of vacuole inheritance. Apical cells of hyphae underwent continuous extension before and after the first cytokinesis event. However, the resulting mother cell and sub-apical compartments did not immediately reenter the cell cycle and instead underwent cell cycle arrest before reentering the cycle. Vacuole was inherited asymmetrically at cytokinesis so that the distal, arrested compartments inherited most vacuole and the growing apical cell inherited most cytoplasm. Hydroxyurea release experiments demonstrated that the arrested, vacuolated hyphal compartments were in the G1 phase of the cycle. The period of cell cycle arrest was decreased by the provision of assimilatable forms of nitrogen, suggesting that the hyphal cell cycle is regulated by nitrogen limitation that results in sup-apical cell cycle arrest. This pattern of growth is distinct from that of the synchronous, symmetrical development of pseudohyphae of C. albicans and other yeast species. These observations suggest that the cellular vacuole space correlates with alterations in the cell cycles of different cell types and that the total organelle space may influence size-regulated functions and hence the timing of the eukaryotic cell cycle.

Impact of Renal Function on Outcomes With Edoxaban in the ENGAGE AF-TIMI 48 Trial

Background: Edoxaban, an oral factor Xa inhibitor with 50% renal clearance, was noninferior to well-managed warfarin for stroke or systemic embolism (S/SE) prevention and reduced bleeding in patients with atrial fibrillation. We evaluated the efficacy and safety of edoxaban versus warfarin across the range of baseline creatinine clearance (CrCl) in the ENGAGE AF-TIMI 48 trial (Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation–Thrombolysis in Myocardial Infarction Study 48) with a focus on the higher-dose edoxaban regimen (HDER) and the upper range of CrCl. Methods: A total of 14 071 patients with atrial fibrillation at moderate to high risk for stroke were randomized to warfarin or HDER (60 mg daily or a 50% dose reduction to 30 mg daily for CrCl 30–50 mL/min, body weight of ⩽60 kg, or use of a potent phosphorylated glycoprotein inhibitor). CrCl <30 mL/min was exclusionary. End points of S/SE, International Society on Thrombosis and Haemostasis major bleeding, and the net clinical outcome of S/SE/major bleeding or death were evaluated by intention-to-treat analysis using the prespecified CrCl cut point of 50 mL/min and additional exploratory cut points with the Cockcroft-Gault formula. A sensitivity analysis was performed with the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) formula for estimating renal function. Results: The relative risk of S/SE with HDER versus warfarin in patients with CrCl >50 mL/min (hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.72–1.04) was similar to that in patients with CrCl ⩽50 mL/min (HR, 0.87; 95% CI, 0.65–1.18; P for interaction=0.94). Several exploratory analyses suggested lower relative efficacy for the prevention of S/SE with HDER compared with warfarin at higher levels of CrCl (CrCl ⩽50 mL/min: HR, 0.87; 95% CI, 0.65–1.18; CrCl >50–95 mL/min: HR, 0.78; 95% CI, 0.64–0.96; CrCl >95 mL/min: HR, 1.36; 95% CI, 0.88–2.10; P for interaction=0.08). Bleeding rates were lower at all levels of CrCl with HDER (P for interaction=0.11). Because of the preserved effect on bleeding, the net clinical outcome was more favorable with HDER across the range of CrCl (P for interaction=0.73). Similar findings were observed in the sensitivity analysis using the CKD-EPI formula. Conclusions: Although there was an apparent decrease in relative efficacy to prevent arterial thromboembolism in the upper range of CrCl, the safety and net clinical benefit of HDER compared with warfarin are consistent across the range of renal function. Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00781391.

Human melanoma cells expressing V600E B-RAF are susceptible to IGF1R targeting by small interfering RNAs

The type 1 insulin-like growth factor receptor (IGF1R) is overexpressed by malignant melanomas compared with benign naevi, and mediates proliferation, motility and protection from apoptosis. However, the utility of IGF1R targeting as anti-cancer therapy may be limited by activating mutations in downstream signaling intermediates. We previously showed that IGF1R knockdown blocked survival of prostate cancer cells in which Akt activation was deregulated by PTEN loss. The current study investigated effects of IGF1R targeting in cells harboring activating RAS-RAF mutations, found in 70–80% of human melanomas. We assembled a panel of eight human melanoma cell lines: two expressing wild-type (WT) B-RAF and N-RAS, two with activating N-RAS mutations and four harboring V600E B-RAF. We also generated isogenic cell populations overexpressing WT or V600E B-RAF. Cells expressing V600E B-RAF were relatively resistant to apoptosis. However, IGF1R gene silencing was capable of inducing significant inhibition of survival, enhancement of apoptosis, and ∼two-fold sensitization to cisplatin and temozolomide. These effects were independent of mutation status and were associated with reduced activation of Akt and also, unexpectedly, of ERKs. These results support development of IGF1R targeting as therapy for melanoma, regardless of the presence of activating mutations in the RAS-RAF pathway.

Atherothrombotic Risk Stratification and the Efficacy and Safety of Vorapaxar in Patients with Stable Ischemic Heart Disease and Previous Myocardial Infarction

Background: Patients with stable ischemic heart disease and previous myocardial infarction (MI) vary in their risk for recurrent cardiovascular events. Atherothrombotic risk assessment may be useful to identify high-risk patients who have the greatest potential to benefit from more intensive secondary preventive therapy such as treatment with vorapaxar. Methods: We identified independent clinical indicators of atherothrombotic risk among 8598 stable, placebo-treated patients with a previous MI followed up for 2.5 years (median) in TRA 2°P-TIMI 50 [Thrombin Receptor Antagonist in Secondary Prevention of Atherothrombotic Ischemic Events–TIMI 50]. The efficacy and safety of vorapaxar (SCH 530348; MK-5348) were assessed by baseline risk among patients with previous MI without prior stroke or transient ischemic attack for whom there is a clinical indication for vorapaxar. End points were cardiovascular death, MI, or ischemic stroke and GUSTO (Global Use of Strategies to Open Occluded Coronary Arteries) severe bleeding. Results: The 9 independent risk predictors were age, diabetes mellitus, hypertension, smoking, peripheral arterial disease, previous stroke, previous coronary bypass grafting, heart failure, and renal dysfunction. A simple integer-based scheme using these predictors showed a strong graded relationship with the rate of cardiovascular death/MI/ischemic stroke and the individual components (P for trend <0.001 for all). High-risk patients (≥3 risk indicators; 20% of population) had a 3.2% absolute risk reduction in cardiovascular disease/MI/ischemic stroke with vorapaxar, and intermediate-risk patients (1–2 risk indicators; 61%) had a 2.1% absolute risk reduction (P<0.001 each), translating to a number needed to treat of 31 and 48. Bleeding increased across risk groups (P for trend<0.01); however, net clinical outcome was increasingly favorable with vorapaxar across risk groups. Fatal bleeding or intracranial hemorrhage was 0.9% with both treatments in high-risk patients. Conclusions: Stratification of baseline atherothrombotic risk can assist with therapeutic decision making for vorapaxar use for secondary prevention after MI. Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT00526474.

Efficacy and Safety of Vorapaxar With and Without a Thienopyridine for Secondary Prevention in Patients With Previous Myocardial Infarction and No History of Stroke or Transient Ischemic Attack: Results from TRA 2°P-TIMI 50.

Background— Vorapaxar antagonizes protease-activated receptor 1, the primary receptor for thrombin on human platelets, and reduces recurrent thrombotic events in stable patients with a previous myocardial infarction (MI). We wished to determine whether the efficacy and safety of antiplatelet therapy with vorapaxar was modified by concurrent thienopyridine use. Methods and Results— The Thrombin Receptor Antagonist in Secondary Prevention of Atherothrombotic Ischemic Events–Thrombolysis in Myocardial Infarction 50 (TRA 2°P-TIMI 50) was a randomized, double-blind, placebo-controlled trial of vorapaxar in 26 449 patients with previous atherothrombosis. This prespecified analysis included 16 897 patients who qualified with a MI in the preceding 2 weeks to 12 months and was restricted to patients without a history of stroke or transient ischemic attack given its contraindication in that population. Randomization was stratified on the basis of planned thienopyridine use. Thienopyridine was planned at randomization in 12 410 (73%). Vorapaxar significantly reduced the composite of cardiovascular death, MI, and stroke in comparison with placebo regardless of planned thienopyridine therapy (planned thienopyridine, hazard ratio, 0.80, 0.70–0.91, P<0.001; no planned thienopyridine, hazard ratio, 0.75; 0.60–0.94, P=0.011; P-interaction=0.67). Findings were similar when patients were stratified by actual thienopyridine use at baseline (P-interaction=0.82) and through 18 months (P-interaction=0.44). Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO) moderate or severe bleeding risk was increased with vorapaxar and was not significantly altered by planned thienopyridine (planned, hazard ratio, 1.50; 1.18–1.89, P<0.001; no planned, hazard ratio, 1.90, 1.17–3.07, P=0.009; P-interaction=0.37) or actual thienopyridine use (P-interaction=0.24). Conclusions— Vorapaxar reduced cardiovascular death, MI, or stroke in stable patients with a history of previous MI, whether treated concomitantly with a thienopyridine or not. The relative risk of moderate or severe bleeding was similarly increased irrespective of thienopyridine use. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00526474.

The benefit of adding ezetimibe to statin therapy in patients with prior coronary artery bypass graft surgery and acute coronary syndrome in the IMPROVE-IT trial

AIMS To examine the efficacy and safety of ezetimibe added to statin in patients with prior coronary artery bypass graft surgery (CABG) following hospitalization for an acute coronary syndrome (ACS). METHODS AND RESULTS In the IMPROVE-IT trial, post-ACS patients with mean low density lipoprotein cholesterol (LDL-C) of 93.8 mg/dL at presentation were randomized to simvastatin/ezetimibe or simvastatin/placebo. The primary endpoint was cardiovascular death, major coronary event or stroke, and the median follow-up was 6 years. Efficacy and safety endpoints were examined by prior CABG status. Among 18 134 patients, 1684 (9.3%) had a prior CABG (median age 69 years, 82% male). During the trial, the median time-weighted LDL-C level was 55.0 mg/dL with simvastatin/ezetimibe vs. 69.9 mg/dL with simvastatin/placebo in patients with prior CABG (P < 0.001), and it was 53.6 mg/dL vs. 69.5 mg/dL, respectively, in patients without prior CABG (P < 0.001). The rate of the primary endpoint was higher in patients with vs. without prior CABG [56% vs. 32%, adj. hazard ratio 1.45, 95% confidence interval (CI) 1.33-1.58]. Patients with prior CABG receiving simvastatin/ezetimibe had an 8.8% (95% CI 3.1-14.6%) lower absolute risk over simvastatin/placebo in the primary endpoint, whereas patients without prior CABG had a 1.3% (95% CI 0-2.6%) lower absolute risk (P-interaction = 0.02). There were no between-group significant differences in safety endpoints. CONCLUSION The clinical benefit of adding ezetimibe to statin appears to be enhanced in patients with prior CABG, supporting the use of intensive lipid lowering therapy in these high-risk patients following ACS.

Inflammatory and Cholesterol Risk in the FOURIER Trial

Background: In the FOURIER trial (Further Cardiovascular Outcomes Research With PCSK9 Inhibition in Patients With Elevated Risk), the PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitor evolocumab reduced low-density lipoprotein cholesterol (LDL-C) and cardiovascular risk. It is not known whether the efficacy of evolocumab is modified by baseline inflammatory risk. We explored the efficacy of evolocumab stratified by baseline high-sensitivity C-reactive protein (hsCRP). We also assessed the importance of inflammatory and residual cholesterol risk across the range of on-treatment LDL-C concentrations. Methods: Patients (n=27 564) with stable atherosclerotic cardiovascular disease and LDL-C ≥70 mg/dL on a statin were randomly assigned to evolocumab versus placebo and followed for a median of 2.2 years (1.8–2.5). The effects of evolocumab on the primary end point of cardiovascular death, myocardial infarction, stroke, hospitalization for unstable angina or coronary revascularization, and the key secondary end point of cardiovascular death, myocardial infarction, or stroke were compared across strata of baseline hsCRP (<1, 1–3, and >3 mg/dL). Outcomes were also assessed across values for baseline hsCRP and 1-month LDL-C in the entire trial population. Multivariable models adjusted for variables associated with hsCRP and 1-month LDL-C were evaluated. Results: A total of 7981 (29%) patients had a baseline hsCRP<1 mg/L, 11 177 (41%) had a hsCRP 1 to 3 mg/L, and 8337 (30%) had a hsCRP >3 mg/L. Median (interquartile range) baseline hsCRP was 1.8 (0.9–3.6) mg/L and levels were not altered by evolocumab (change at 48 weeks of –0.2 mg/dL [–1.0 to 0.4] in both treatment arms). In the placebo arm, patients in higher baseline hsCRP categories experienced significantly higher 3-year Kaplan-Meier rates of the primary and key secondary end points: 12.0%, 13.7%, and 18.1% for the primary end point (Ptrend<0.0001) and 7.4%, 9.1%, and 13.2% for the key secondary end point (Ptrend<0.0001) for categories of <1, 1 to 3, and >3 mg/dL, respectively. The relative risk reductions for the primary end point and key secondary end point with evolocumab were consistent across hsCRP strata (P-interactions>0.15 for both). In contrast, the absolute risk reductions with evolocumab tended to be greater in patients with higher hsCRP: 1.6%, 1.8%, and 2.6% and 0.8%, 2.0%, and 3.0%, respectively, for the primary and key secondary end points across hsCRP strata. In adjusted analyses of the association between LDL-C and hsCRP levels and cardiovascular risk, both LDL-C and hsCRP were independently associated with the primary outcome (P<0.0001 for each). Conclusions: LDL-C reduction with evolocumab reduces cardiovascular events across hsCRP strata with greater absolute risk reductions in patients with higher-baseline hsCRP. Event rates were lowest in patients with the lowest hsCRP and LDL-C. Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01764633.