Murine models of anaphylaxis have suggested that IgG antibody/allergen complexes interacting with Fcγ receptors on basophils and neutrophils release platelet-activating factor and other vasoactive ...mediators.8 This mechanism has not been substantiated in humans; however, the robust baseline IgG anti-PEG titers and high plasma concentrations of PEG (~20 μg/mL) achieved after bolus pegnivacogin dosing are consistent with murine studies demonstrating high levels of both IgG and antigen as key factors in this type of reaginic IgG anaphylaxis.8,9 We cannot definitively determine which of these or other mechanisms is applicable.
Summary Background REG1 is a novel anticoagulation system consisting of pegnivacogin, an RNA aptamer inhibitor of coagulation factor IXa, and anivamersen, a complementary sequence reversal ...oligonucleotide. We tested the hypothesis that near complete inhibition of factor IXa with pegnivacogin during percutaneous coronary intervention, followed by partial reversal with anivamersen, would reduce ischaemic events compared with bivalirudin, without increasing bleeding. Methods We did a randomised, open-label, active-controlled, multicentre, superiority trial to compare REG1 with bivalirudin at 225 hospitals in North America and Europe. We planned to randomly allocate 13 200 patients undergoing percutaneous coronary intervention in a 1:1 ratio to either REG1 (pegnivacogin 1 mg/kg bolus >99% factor IXa inhibition followed by 80% reversal with anivamersen after percutaneous coronary intervention) or bivalirudin. Exclusion criteria included ST segment elevation myocardial infarction within 48 h. The primary efficacy endpoint was the composite of all-cause death, myocardial infarction, stroke, and unplanned target lesion revascularisation by day 3 after randomisation. The principal safety endpoint was major bleeding. Analysis was by intention to treat. This trial is registered at ClinicalTrials.gov , identifier NCT01848106 . The trial was terminated early after enrolment of 3232 patients due to severe allergic reactions. Findings 1616 patients were allocated REG1 and 1616 were assigned bivalirudin, of whom 1605 and 1601 patients, respectively, received the assigned treatment. Severe allergic reactions were reported in ten (1%) of 1605 patients receiving REG1 versus one (<1%) of 1601 patients treated with bivalirudin. The composite primary endpoint did not differ between groups, with 108 (7%) of 1616 patients assigned REG1 and 103 (6%) of 1616 allocated bivalirudin reporting a primary endpoint event (odds ratio OR 1·05, 95% CI 0·80–1·39; p=0·72). Major bleeding was similar between treatment groups (seven <1% of 1605 receiving REG1 vs two <1% of 1601 treated with bivalirudin; OR 3·49, 95% CI 0·73–16·82; p=0·10), but major or minor bleeding was increased with REG1 (104 6% vs 65 4%; 1·64, 1·19–2·25; p=0·002). Interpretation The reversible factor IXa inhibitor REG1, as currently formulated, is associated with severe allergic reactions. Although statistical power was limited because of early termination, there was no evidence that REG1 reduced ischaemic events or bleeding compared with bivalirudin. Funding Regado Biosciences Inc.
Pterostilbene (Pt) is a natural polyphenol found in blueberries and several grape varieties. Pt's pharmacological importance was well documented. Nevertheless, the depigmenting effects are not ...demonstrated. We evaluated the Pt's depigmenting effects through autophagy induction in B16F10 cells and inhibition of UVA (3 J/cm2)-irradiated α-MSH in keratinocyte HaCaT cells via Nrf2-mediated antioxidant pathways. Pt (2.5–5μM) attenuated ROS production and downregulated the POMC/α-MSH pathway in HaCaT cells. The conditioned medium-derived from UVA-irradiated HaCaT pretreated with Pt suppressed melanogenesis in B16F10 through MITF-CREB-tyrosinase pathway downregulation. Interestingly, Pt-induced HaCaT autophagy was revealed by enhanced LC3-II accumulation, p62/SQSTM1 activation, and AVO formation. Pt significantly decreased melanosome gp100 but increased LC3-II levels in HaCaT cells exposed to B16F10-derived melanin. Pt activated and facilitated the Nrf2 antioxidant pathway in HaCaT cells leading to increased HO-1, γ-GCLC, and NQO-1 antioxidant protein expression. ERK, AMPK, and ROS pathways mediate the Nrf2 activation. However, Nrf2 knockdown suppressed Pt's antioxidant ability leading to uncontrolled ROS and α-MSH levels after UVA-irradiation suggested the essentiality of the Nrf2 pathway. Moreover, in α-MSH-stimulated B16F10 cells, Pt (10–30 μM) downregulated the MC1R, MITF, tyrosinase, TRP-1/-2, and melanin expression. Further, Pt showed potent anti-melanogenic effects through autophagy induction mechanism in B16F10 cells, verified by increased LC3-II/p62 levels, AVO formation, and Beclin-1/Bcl-2 ratio, decreased ATG4B levels and PI3K/AKT/mTOR pathway. Transmission electron microscopy provided direct evidence by showing autophagosomes engulfing melanosomes following Pt treatment in α-MSH-stimulated B16F10 cells. Moreover, Pt-induced anti-melanogenic activity through the downregulation of CREB-MITF pathway-mediated TRP-1/-2, tyrosinase expressions, melanosome formation, and melanin synthesis was substantially reversed due to 3-MA (autophagy inhibitor) pretreatment or LC3 silencing in B16F10 cells. In vivo results also confirmed that Pt-inhibited tyrosinase expression/activity and endogenous pigmentation in the zebrafish model. Therefore, pterostilbene is a potent skin-whitening and antioxidant agent and could be used in skin-whitening formulations as a topical applicant.
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•Pt inhibits ROS-mediated POMC/α-MSH pathway in UVA-irradiated HaCaT cells.•Pt activates Nrf2-mediated HO-1, γ-GCLC, and NQO-1 expression in HaCaT cells.•Pt-induces autophagy in B16F10 cells leading to melanogenesis inhibition.•Pt-mediates anti-melanogenic mechanisms in α-MSH-stimulated B16F10 cells.•Pt-inhibits tyrosinase expression and endogenous pigmentation in zebrafish model.
Background In the TRACER trial, vorapaxar, a protease-activated receptor-1 antagonist, plus standard care in non–ST-segment elevation acute coronary syndrome (NSTE ACS) patients did not significantly ...reduce the primary composite end point but reduced a key secondary end point and significantly increased bleeding. History of peripheral artery disease (PAD) was a risk-enrichment inclusion criterion. We investigated the efficacy and safety of vorapaxar in NSTE ACS patients with documented PAD. Methods TRACER was a double-blind, randomized trial comparing vorapaxar with placebo in 12,944 patients with NSTE ACS. Results In total, 936 (7.2%) patients had a history of PAD. Ischemic events occurred more frequently among patients with PAD (25.3%) versus no PAD (12.2%, P < .001), and Global Use of Strategies to Open Occluded Coronary Arteries moderate/severe bleeding was more common in PAD (9.1%) versus no PAD (5.0%, P = .004). Similar rates of the composite end point (cardiovascular death, myocardial infarction, or stroke) occurred in patients with PAD treated with vorapaxar and placebo (21.7% vs 24.8%, P interaction = .787). Patients with PAD treated with vorapaxar, when compared with placebo, also had a numerical reduction in peripheral revascularization procedures (8.1% vs 9.0%, P = .158) and a lower extremity amputation rate (0.9% vs 1.5%, P = .107). Vorapaxar increased Global Use of Strategies to Open Occluded Coronary Arteries moderate/severe bleeding similarly in patients with PAD (hazard ratio 1.47, 95% CI 0.89-2.45) and without (hazard ratio 1.48, 95% CI 1.22-1.79; P interaction = .921). Conclusions Patients with NSTE ACS and PAD were at increased risk for ischemic events. Lower rates of ischemic end points, peripheral revascularization, and amputation with vorapaxar did not reach statistical significance but warrant further investigation. Vorapaxar increased bleeding in both patients with and without PAD at a similar magnitude of risk.
Objectives This study evaluated effects of protease-activated receptor-1 antagonist vorapaxar (Merck, Whitehouse Station, New Jersey) versus placebo among the TRACER (Thrombin Receptor Antagonist for ...Clinical Event Reduction in Acute Coronary Syndrome) study patients with non–ST-segment elevation acute coronary syndromes undergoing coronary artery bypass grafting (CABG). Background Platelet activation may play a key role in graft occlusion, and antiplatelet therapies may reduce ischemic events, but perioperative bleeding risk remains a major concern. Although the TRACER study did not meet the primary quintuple composite outcome in the overall population with increased bleeding, an efficacy signal with vorapaxar was noted on major ischemic outcomes, and preliminary data suggest an acceptable surgical bleeding profile. We aimed to assess efficacy and safety of vorapaxar among CABG patients. Methods Associations between treatment and ischemic and bleeding outcomes were assessed using time-to-event analysis. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using the Cox hazards model. Event rates were estimated using the Kaplan-Meier method. Results Among 12,944 patients, 1,312 (10.1%) underwent CABG during index hospitalization, with 78% on the study drug at the time of surgery. Compared with placebo CABG patients, vorapaxar-treated patients had a 45% lower rate of the primary endpoint (i.e., a composite of death, myocardial infarction, stroke, recurrent ischemia with rehospitalization, or urgent coronary revascularization during index hospitalization) (HR: 0.55; 95% CI: 0.36 to 0.83; p = 0.005), with a significant interaction (p = 0.012). The CABG-related Thrombolysis In Myocardial Infarction major bleeding was numerically higher with vorapaxar, but not significantly different between vorapaxar and placebo (9.7% vs. 7.3%; HR: 1.36; 95% CI: 0.92 to 2.02; p = 0.12), with no excess in fatal bleeding (0% vs. 0.3%) or need for reoperation (4.7% vs. 4.6%). Conclusions In non–ST-segment elevation acute coronary syndrome patients undergoing CABG, vorapaxar was associated with a significant reduction in ischemic events and no significant increase in major CABG-related bleeding. These data show promise for protease-activated receptor 1 antagonism in patients undergoing CABG and warrant confirmatory evidence in randomized trials. (Trial to Assess the Effects of SCH 530348 in Preventing Heart Attack and Stroke in Patients With Acute Coronary Syndrome TRA·CER Study P04736AM3; NCT00527943 )
Background Protease-activated receptor 1 antagonism with vorapaxar represents a novel strategy for platelet inhibition. In TRACER, vorapaxar was compared with placebo plus standard of care among ...12,944 patients with non–ST-segment elevation acute coronary syndromes. We anticipated that most patients would have received clopidogrel as part of standard care. We investigated the modification of vorapaxar's effect associated with clopidogrel use over time. Methods The marginal structural model method was used to estimate causal modification of vorapaxar effect by use of clopidogrel over time. The primary outcomes were the composite of cardiovascular death, myocardial infarction, or stroke and Global Use of Strategies to Open Occluded Coronary Arteries moderate or severe bleeding. The event accrual period excluded the time during which clopidogrel was clinically warranted. Results Among 12,887 patients who received study medication, 11,117 (86.3%) received clopidogrel before randomization, of whom 38.5% stopped later in the trial (median time to stoppage 200 days with placebo; interquartile range IQR 14-367) (186 days with vorapaxar; IQR 17-366). In total, 1,770 (13.7%) patients were not on clopidogrel at randomization, of whom 47.8% started afterward (median time to start 2 days; IQR 2-4). During the period of event accrual, vorapaxar was associated with a 26% reduction in the composite of cardiovascular death, myocardial infarction, or stroke when used with clopidogrel (hazard ratio HR 0.74; 95% CI 0.60-0.91) and a 24% reduction when used without clopidogrel (HR 0.76; 95% CI 0.56-1.02) (interaction; P = .89). The hazard of Global Use of Strategies to Open Occluded Coronary Arteries bleeding with vorapaxar was not significantly different without clopidogrel (HR 1.33; 95% CI 0.81-2.20) or with clopidogrel (HR 1.09; 95% CI 0.76-1.56) (interaction; P = .53). Conclusions We observed no interaction between vorapaxar and clopidogrel after non–ST-segment elevation acute coronary syndromes on efficacy or safety outcomes, supporting a complementary role of protease-activated receptor 1 and P2Y12 antagonism.
The therapeutic potential of vorapaxar in patients with non–ST-segment elevation acute coronary syndrome undergoing percutaneous coronary intervention (PCI) is unknown. This prespecified analysis of ...a postrandomization subgroup evaluated the effects of vorapaxar compared with placebo among Thrombin Receptor Antagonist for Clinical Event Reduction in Acute Coronary Syndrome (TRACER) participants undergoing PCI, focusing on the implanted stent type (drug-eluting stent DES vs bare-metal stent BMS). Among 12,944 recruited patients, 7,479 (57.8%) underwent PCI during index hospitalization, and 3,060 (40.9%) of those patients received exclusively BMS, whereas 4,015 (53.7%) received DES. The median (twenty-fifth, seventy-fifth percentiles) duration of thienopyridine therapy was 133 days (47, 246) with BMS and 221 days (88, 341) with DES. At 2 years among patients undergoing PCI, the primary (cardiovascular death, myocardial infarction, stroke, recurrent ischemia with rehospitalization, or urgent coronary revascularization) and secondary (cardiovascular death, myocardial infarction, or stroke) end points did not differ between vorapaxar and placebo groups, which was consistent with the treatment effect observed in the overall study population (p value for interaction = 0.540). However, the treatment effect trended greater (p value for interaction = 0.069) and the risk for bleeding in patients taking vorapaxar versus placebo appeared attenuated in BMS-only recipients. After adjustment for confounders, the interaction was no longer significant (p value = 0.301). The covariate that mostly explained the stent-type-by-treatment interaction was the duration of clopidogrel therapy. In conclusion, among patients with PCI, the effect of vorapaxar is consistent with the overall TRACER results. Patients who received a BMS underwent shorter courses of clopidogrel therapy and displayed trends toward greater ischemic benefit from vorapaxar and lesser bleeding risk, compared with patients who received a DES.
Thrombin Receptor Antagonist for Clinical Event Reduction in Acute Coronary Syndrome (TRACER) trial compared vorapaxar and placebo in 12,944 high-risk patients with non–ST-segment elevation acute ...coronary syndrome. We explored aspirin (ASA) use and its association with outcomes. Kaplan-Meier event rates were compared in groups defined by ASA dose (low, medium, and high). Landmark analyses with covariate adjustment were performed for 0 to 30, 31 to 180, and 181 to 365 days. Of 12,515 participants, 7,523, 1,049, and 3,943 participants were treated with low-, medium-, and high-dose ASA at baseline, respectively. Participants enrolled in North America versus elsewhere were more often treated with a high dose at baseline (66% vs 19%) and discharge (60% vs 3%). Unadjusted cardiovascular death, myocardial infarction, stroke, hospitalization for ischemia, or urgent revascularization event rates tended to be higher with higher baseline ASA (18.45% low, 19.13% medium, and 20.27% high; p for trend = 0.15573). Unadjusted and adjusted hazard ratios (95% confidence intervals) for effect of vorapaxar on cardiovascular (unadjusted p for interaction = 0.065; adjusted p for interaction = 0.140) and bleeding (unadjusted p for interaction = 0.915; adjusted p for interaction = 0.954) outcomes were similar across groups. Landmark analyses showed similar safety and efficacy outcomes with vorapaxar and placebo by ASA dose at each time point except for 0 to 30 days, when vorapaxar tended to be worse for efficacy (hazard ratio 1.13, 95% confidence interval 0.89 to 1.44, p for interaction = 0.0157). In conclusion, most TRACER participants were treated with low-dose ASA, although a high dose was common in North America. High-dose participants tended to have higher rates of ischemic and bleeding outcomes. Although formal statistical testing did not reveal heterogeneity in vorapaxar's effect across dose subgroups, consistent trends support use of low-dose ASA with other antiplatelet therapies.
Abstract Background The Bleeding Academic Research Consortium (BARC) scale has been proposed to standardize bleeding endpoint definitions and reporting in cardiovascular trials. Validation in large ...cohorts of patients is needed. Objectives This study sought to investigate the relationship between BARC-classified bleeding and mortality and compared its prognostic value against 2 validated bleeding scales: TIMI (Thrombolysis In Myocardial Infarction) and GUSTO (Global Use of Strategies to Open Occluded Arteries). Methods We analyzed bleeding in 12,944 patients with acute coronary syndromes without ST-segment elevation, with or without early invasive strategy. The main outcome measure was all-cause death. Results During follow-up (median: 502 days), noncoronary artery bypass graft (CABG) bleeding occurred in 1,998 (15.4%) patients according to BARC (grades 2, 3, or 5), 484 (3.7%) patients according to TIMI minor/major, and 514 (4.0%) patients according to GUSTO moderate/severe criteria. CABG-related bleeding (BARC 4) occurred in 155 (1.2%) patients. Patients with BARC (2, 3, or 4) bleeding had a significant increase in risk of death versus patients without bleeding (BARC 0 or 1); the hazard was highest in the 30 days after bleeding (hazard ratio: 7.35; 95% confidence interval: 5.59 to 9.68; p < 0.0001) and remained significant up to 1 year. The hazard of mortality increased progressively with non-CABG BARC grades. BARC 4 bleeds were significantly associated with mortality within 30 days (hazard ratio: 10.05; 95% confidence interval: 5.41 to 18.69; p < 0.0001), but not thereafter. Inclusion of BARC (2, 3, or 4) bleeding in the 1-year mortality model with baseline characteristics improved it to an extent comparable to TIMI minor/major and GUSTO moderate/severe bleeding. Conclusions In patients with acute coronary syndromes without ST-segment elevation, bleeding assessed with the BARC scale was significantly associated with risk of subsequent death up to 1 year after the event and risk of mortality increased gradually with higher BARC grades. Our results support adoption of the BARC bleeding scale in ACS clinical trials. (Trial to Assess the Effects of Vorapaxar SCH 530348; MK-5348 in Preventing Heart Attack and Stroke in Participants With Acute Coronary Syndrome TRACER Study P04736; NCT00527943 )
The purpose of this study was to determine whether the degree of esophageal circumferential tumor involvement and tumor size of resectable esophageal squamous cell carcinoma (ESCC) assessed on ...computed tomography could predict T category.
One hundred eighty-five consecutive patients with ESCC underwent radical esophagectomy less than 3 weeks after contrast-enhanced computed tomography. The degree of esophageal circumferential tumor involvement and tumor size of ESCC expressed as tumor length, maximal thickness, and gross tumor volume were evaluated on computed tomography. Statistical analyses were performed to identify whether degree of esophageal circumferential tumor involvement and tumor size could predict T category.
Esophageal squamous cell carcinoma with whole esophageal circumferential tumor involvement was more likely to be at T3 category, whereas tumor without this involvement was more likely to be at T1 or T2 category (p < 0.001). Degree of esophageal circumferential tumor involvement could distinguish ESCC at T1/T2 from ESCC at T3 category with a sensitivity of 77.4% and specificity of 74.8%. Tumor length, maximal thickness, and gross tumor volume increased with advancing T category (p < 0.001). Mann-Whitney tests showed that tumor size could distinguish T category (p < 0.001). Compared with degree of esophageal circumferential tumor involvement, tumor length, and maximal thickness, gross tumor volume could be a better differentiating indicator between T1 and T2 categories (cutoff, 5.15 cm(3)), between T1 and T3 categories (cutoff, 11.1 cm(3)), between T2 and T3 categories (cutoff, 17.75 cm(3)), and between T1/T2 and T3 categories (cutoff, 15.9 cm(3)), with sensitivity of 81.3%, 88.8%, 68.8%, and 78.8%, and specificity of 76%, 88%, 67.5%, and 75.4%, respectively.
Gross tumor volume of resectable ESCC measured with computed tomography could be a recommended indicator for predicting T category.
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