Robert J. Anders

Oral Glycoprotein IIb/IIIa Inhibition With Orbofiban in Patients With Unstable Coronary Syndromes (OPUS-TIMI 16) Trial

BACKGROUND Although intravenous glycoprotein IIb/IIIa inhibitors are beneficial in patients with acute coronary syndromes, prolonged oral IIb/IIIa inhibition might provide an additional reduction in recurrent events. METHODS AND RESULTS Investigators at 888 hospitals in 29 countries enrolled 10 288 patients with acute coronary syndromes, which was defined as ischemic pain at rest within 72 hours of randomization, associated with positive cardiac markers, electrocardiographic changes, or prior cardiovascular disease. Patients received aspirin and were randomized to receive, for the duration of the trial, (1) 50 mg of orbofiban twice daily (50/50 group), (2) 50 mg of orbofiban twice daily for 30 days followed by 30 mg of orbofiban twice daily (50/30 group), or (3) a placebo. The primary composite end point was death, myocardial infarction, recurrent ischemia requiring rehospitalization, urgent revascularization, or stroke. The trial was terminated prematurely because of an unexpected increase in 30-day mortality in the 50/30 orbofiban group. Mortality through 10 months was 3.7% for the placebo group versus 5.1% in the 50/30 group (P=0.008) and 4.5% in the 50/50 group (P=0.11). There were no differences in the primary end point (22.9%, 23.1%, and 22.8%, for the placebo, 50/30, and 50/50 groups, respectively). Major or severe bleeding (but not intracranial hemorrhage) was higher with orbofiban; it occurred in 2. 0%, 3.7% (P=0.0004), and 4.5% (P<0.0001) of patients, respectively. Exploratory subgroup analyses found that patients who underwent percutaneous coronary intervention had a lower mortality and a significant reduction in the composite end point (P=0.001) with orbofiban. CONCLUSIONS -Fixed-dose orbofiban failed to reduce major cardiovascular events and was associated with increased mortality in this broad population of patients with acute coronary syndromes; however, a benefit was observed among patients who underwent percutaneous coronary intervention.

Baseline Characteristics and Early Blood Pressure Control in the CONVINCE Trial

Blood pressure (BP) control rates around the world are suboptimal. Part 2 of the National Health and Nutrition Educational Survey (NHANES) III indicates that only 27.4% of hypertensive Americans aged 18 to 74 years have a BP of <140/90 mm Hg. We wanted to assess BP control during the first 2 years and to describe the baseline characteristics of patients enrolled in the Controlled ONset Verapamil INvestigation of Cardiovascular Endpoints (CONVINCE) Study, an international clinical trial that compares outcomes in hypertensive patients randomized to initial treatment with either controlled-onset extended-release verapamil or the investigator’s choice of atenolol or hydrochlorothiazide. At randomization, BP was <140/90 mm Hg in only 20.3% of the 16 602 subjects (average±SD age 65.6±7.4 years; 56% women, 84% white/7% black/7% Hispanic). The average BP at enrollment was 148/85 mm Hg for patients taking BP medications (n=13 879) and 161/94 mm Hg for previously untreated patients (n=2723). After medication titration, with a transtelephonic computer that recommended an increase in the dose or number of antihypertensive agents whenever the BP was 140/90 mm Hg, 84.8% of the subjects attained the goal BP. During 2 years of treatment, BP control was maintained in 67% to 69% of the subjects (69% to 71% for systolic BP of <140 mm Hg and 90% for diastolic BP of <90 mm Hg). These data suggest that the control of systolic BP is more difficult than the control of diastolic BP. The US national goal of having 50% of hypertensives with a BP of <140/90 mm Hg may be achievable if a forced titration strategy is used. Interested investigators, free care and medications, and well-educated subjects may make the attainment of such a goal easier in the CONVINCE study than in the general population.

First chronic platelet glycoprotein IIb/IIIa integrin blockade. A randomized, placebo-controlled pilot study of xemilofiban in unstable angina with percutaneous coronary interventions.

BACKGROUND Clinical studies have demonstrated the efficacy of intravenous administration of agents that block platelet glycoprotein IIb/IIIa receptors in the setting of percutaneous coronary revascularization. Although the optimal duration of treatment has not been determined, more prolonged receptor blockade has been associated with increased efficacy. Orally active glycoprotein IIb/IIIa receptor antagonists may be advantageous and required for chronic therapy. METHODS AND RESULTS Thirty patients with unstable angina who were undergoing percutaneous coronary interventions were randomized to placebo or Xemilofiban 35 mg orally before and 20 to 25 mg TID for 30 days after angioplasty. Bleeding events, platelet aggregation, and pharmacokinetic and hematologic parameters were assessed during hospitalization and at 2 and 4 weeks after drug initiation. Xemilofiban produced a rapid, sustained, marked inhibition of platelet aggregation. ADP-induced platelet aggregation at 2 hours after the initial dose at 2 and 4 weeks was 15%, 8%, and 11% in the Xemilofiban group compared with 80%, 68%, and 69% in the placebo group. Among 20 patients randomized to Xemilofiban there was 1 death after emergency coronary bypass surgery complicated by severe bleeding diathesis, and 3 patients had major bleeding events. Patients on Xemilofiban for 30 days reported episodes of mild mucocutaneous bleeding. CONCLUSIONS Xemilofiban, an orally active glycoprotein IIb/ IIIa receptor inhibitor, produced rapid, sustained, extensive inhibition of platelet aggregation for a period of up to 30 days. At the dose initially tested, however, acute major bleeding and mucocutaneous bleeding during chronic administration were encountered.

Pharmacodynamic Efficacy, Clinical Safety, and Outcomes After Prolonged Platelet Glycoprotein IIb/IIIa Receptor Blockade With Oral Xemilofiban Results of a Multicenter, Placebo-Controlled, Randomized Trial

BACKGROUND Parenteral administration of platelet glycoprotein IIb/IIIa (GP IIb/IIIa) receptor blockers can reduce ischemic complications of coronary angioplasty. Orally active GP IIb/IIIa blockers may allow more sustained receptor antagonism with the potential for long-term secondary prevention. The pharmacodynamic efficacy, clinical safety, and outcomes after prolonged receptor blockade with an orally active GP IIb/IIIa antagonist are not known. The Oral Glycoprotein IIb/IIIa Receptor Blockade to Inhibit Thrombosis (ORBIT) Trial is a multicenter, placebo-controlled, randomized trial of xemilofiban, an oral platelet GP IIb/IIIa blocking agent, administered to patients after percutaneous coronary intervention. METHODS AND RESULTS After successful elective percutaneous coronary intervention, 549 patients were randomized to receive either placebo or xemilofiban in a dose of 15 or 20 mg. Stented patients randomized to placebo also received ticlopidine 250 mg orally BID for 4 weeks. Patients who received abciximab during the coronary intervention and who were randomized to receive xemilofiban were administered a reduced dosage (10 mg TID for 2 weeks) followed by the randomized maintenance dose of 15 or 20 mg BID for 2 more weeks. All patients received 325 mg aspirin PO QD. Ex vivo platelet aggregation in response to 20 micromol/L ADP and 4 microg/mL collagen was measured over time after the initial dose of study drug and at days 14 and 28 of long-term therapy in 230 patients. All patients were followed clinically for 90 days. Xemilofiban inhibited platelet aggregation to both ADP and collagen with peak levels of inhibition that were similar at 14 and 28 days of long-term oral therapy. Plasma levels of xemilofiban correlated with the degree of platelet inhibition. Peak platelet inhibition on day 1 correlated with the subsequent occurrence of insignificant or mild bleeding events. Although this study was not powered to evaluate differences in clinical outcomes, a trend (P=0.04) was observed for reduction of cardiovascular events at 3 months in patients not treated with abciximab who received the highest dose (20 mg) of xemilofiban studied. CONCLUSIONS Xemilofiban inhibited platelet aggregation and was well tolerated during 28 days of long-term oral therapy. The observed trend in reduction of cardiovascular events in follow-up awaits confirmation in the larger-scale phase III study (EXCITE trial) currently in progress.

Nocturnal dosina of a novel delivery system of verapamil for systemic hypertension

Abstract To evaluate the efficacy and safety of a novel delivery system of physiologic pattern release (PPR)-verapamil administered nocturnaily to patients with stages I and II hypertension using ambulatory blood pressure (BP) monitoring, we performed a multicenter (17 centers), double-blind, randomized, placebo-controlled, parallel-group trial with placebo and 120, 180, 360, and 540 mg of verapamil in 287 randomized patients. The delivery system has a delay in the release of verapamil for 4 to 6 hours, and then delivers the drug from an osmotic pumping system for approximately 12 hours. Patients were dosed at 10 P.M. The primary end point was change from baseline in trough diastolic BP assessed by ambulatory BP monitoring from 6 to 10 P.M. after 8 weeks of therapy, whereas secondary measures included changes from baseline in peak, early morning (6 to 10 A.M.) systolic and diastolic BP, trough clinic BP, and 24-hour average daytime (8 A.M. to 8 P.M.) and nighttime (8 P.M. to 8 A.M.) BP. The 180, 360, and 540 mg verapamil doses achieved statistically significant reductions in trough (6 to 10 P.M.) diastolic BP (−3.9 ± 1.0, −7.8 ± 1.2, and −10.6 ± 1.1 mm Hg, respectively). Reductions in peak early morning (6 to 10 A.M.) diastolic BP were greater (−4.6 ± 0.9, −13.3 ± 1.2, and −19.0 ± 1.2, for 180, 360, and 540 mg, respectively). These data demonstrate that this novel delivery system of verapamil administered nocturnaily produced changes in BP that followed the circadian variability of BP: lower, but significant reductions during sleep, when ambulatory BP is intrinsically lowest in patients with hypertension, and appropriately larger reductions during early morning awakening and day-time hours when ambulatory BP levels accelerate and plateau to the highest levels over a 24-hour period.

Intra- and interreader reproducibility of magnetic resonance imaging for quantifying the lipid-rich necrotic core is improved with gadolinium contrast enhancement

To test the hypothesis that intra‐ and interreader reproducibility for measuring the lipid‐rich necrotic core (LR‐NC) size is significantly improved with gadolinium (Gd) contrast‐enhanced magnetic resonance imaging (CEMRI) compared to non‐CEMRI.

Sustained Platelet Glycoprotein IIb/IIIa Blockade With Oral Xemilofiban in 170 Patients After Coronary Stent Deployment

BACKGROUND Inhibition of platelet aggregation with parenteral glycoprotein (GP) IIb/IIIa receptor blockers can reduce the ischemic complications of angioplasty. Sustained efficacy and safety of protracted GP IIb/IIIa blockade with an orally administered agent have not previously been determined. This study is the first randomized, dose-ranging, single-blind, placebo-controlled trial of xemilofiban, an oral platelet GP IIb/IIIa receptor antagonist, administered to patients after intracoronary stent deployment. The pharmacodynamic efficacy of xemilofiban-induced platelet inhibition and clinical safety of this agent was evaluated during chronic therapy. METHODS AND RESULTS After elective intracoronary stent deployment, patients were randomized to receive placebo (250 mg ticlopidine P.O. BID) or xemilofiban in doses of 5, 10, 15, or 20 mg P.O. BID. All patients received 325 mg aspirin P.O. QD. Inhibition of ex vivo platelet aggregation in response to 20 micromol/L ADP and 4 microg/mL collagen was measured over time after the initial dose of study drug and at 1 and 2 weeks of chronic therapy. Study drug was discontinued after 2 weeks, and all patients were followed clinically for > or = 30 days. Oral xemilofiban resulted in a dose-dependent inhibition of platelet aggregation in response to both agonists that was sustained through 2 weeks of chronic therapy. Doses of xemilofiban required to achieve > or = 50% inhibition of platelet aggregation were > or = 10 mg, and the duration of inhibition was 8 to 10 hours. No significant hemorrhagic episodes or blood transfusions were observed in this trial. CONCLUSIONS Oral xemilofiban in doses of > or = 10 mg produced > or = 50% inhibition of platelet aggregation in response to ADP and collagen for 8 to 10 hours after dosing. Platelet inhibition was sustained through 2 weeks of chronic therapy. The optimal duration of oral GP IIb/IIIa blockade to effectively suppress recurrent ischemic events after coronary intervention remains to be determined.

Differential Dose-Response to Oral Xemilofiban After Antecedent Intravenous Abciximab Administration for Complex Coronary Intervention

BACKGROUND Placebo-controlled randomized trials of parenteral platelet glycoprotein (GP) IIb/IIIa receptor antagonists have demonstrated reduced ischemic complications of coronary angioplasty. Orally active GP IIb/IIIa blockers are being developed to allow more sustained receptor antagonism with potential for long-term secondary prevention. Sequential therapy with abciximab followed by an oral IIb/IIIa antagonist has not previously been reported. The clinical safety and pharmacodynamics of a sequential therapeutic strategy are unknown. METHODS AND RESULTS Of 74 consecutive patients enrolled in a placebo-controlled, dose-ranging pharmacokinetic/pharmacodynamic study of xemilofiban, a new oral nonpeptide GP IIb/IIIa antagonist, after elective intracoronary stent placement, 17 patients received abciximab during stent deployment as a weight-adjusted intravenous bolus and 12-hour infusion at the discretion of the investigator. Ex vivo platelet aggregation in response to 20 mumol/L ADP and 4 micrograms/mL collagen was measured over time after the first dose of either xemilofiban (5, 10, 15, or 20 mg) or placebo (ticlopidine) administered 8 to 18 hours after termination of abciximab and again after 1 week of twice-daily oral administration of study drug. At baseline, patients who had received abciximab had lower platelet aggregation in response to both agonists (P < .001). A significant dose-response relationship to xemilofiban was observed. Patients who had received abciximab had lower ADP-induced (P < or = .010) and collagen-induced (P < or = .029) platelet aggregation after xemilofiban. This pharmacodynamic interaction was no longer evident at 1 week. No significant clinical bleeding events or blood product transfusions were observed in this trial. CONCLUSIONS Both the magnitude and the duration of pharmacodynamic response to xemilofiban were enhanced by prior abciximab treatment. The potentiated pharmacodynamic response was not evident after 1 week. This observation has implications for the safety and efficacy of sequential parenteral-oral GP IIb/IIIa blockade therapy and may be useful in deriving dose regimens for orally administered compounds.

A comparative trial of controlled-onset, extended-release verapamil, enalapril, and losartan on blood pressure and heart rate changes.

BACKGROUND The excess morning risk of myocardial infarction and stroke may be attributable to the rapid rise in blood pressure (BP) and heart rate in the hours after awakening. The aim of this randomized, double-blinded, placebo-controlled, multicenter study was to compare once-daily, controlled-onset, extended-release (COER-24) verapamil to enalapril and losartan on BP and heart rate during the postawakening morning phase as well as throughout the 24-h period. METHODS A total of 406 patients were randomized to an 8-week forced-titration period with one of the following: 1) COER-24 verapamil 240 mg/day titrated to 360 mg/day; 2) enalapril 10 mg/day titrated to 20 mg/day, 3) losartan 50 mg/day titrated to 100 mg/day, or 4) placebo. Office BP and heart rate and ambulatory 24-h BP monitoring was performed at baseline, 4 weeks, and 8 weeks. RESULTS Each active treatment, as compared with placebo, lowered BP both during the morning hours as well as the entire 24-h period. COER-24 verapamil was more effective in lowering morning systolic (-16.6 mm Hg) and diastolic (-11.9 mm Hg) BP than either enalapril or losartan (P < .001). For the entire 24-h period, the effects of COER-24 verapamil (-11.6/-8.4 mm Hg) were comparable to enalapril (- 13.4/-8.3 mm Hg; P = NS). Losartan achieved a similar 24-h effect on systolic pressure (-9.3 mm Hg) but was less effective on diastolic pressure (-5.4 mm Hg; P = .004 v COER-verapamil). Unlike losartan or enalapril, COER-24 verapamil was the only treatment to lower the heart rate over both the 24-h period (-4.6 beats/min; P < .001) and during waking hours (-4.6 beats/min; P < .001). A blunted rate of rise in BP, heart rate, and rate-pressure product occurred during the postawakening period with COER-verapamil (P = .03) but not with either of the other treatment arms. Lastly, the decline in BP at night was similar for COER-verapamil and losartan and greater with enalapril (P = .014) CONCLUSIONS COER-24 verapamil produces changes in BP and pulse that more closely match the normal circadian hemodynamic rhythms than either do enalapril or losartan.

Results of the Controlled ONset Verapamil INvestigation of Cardiovascular Endpoints (CONVINCE) trial by geographical region.

Objective To examine regional differences in the Controlled ONset Verapamil INvestigation of Cardiovascular Endpoints (CONVINCE) trial. Design Double-blind, randomized, international clinical trial. Setting Six hundred and sixty-one clinical centers in 15 countries. Patients Hypertensive volunteers (n = 16 602) with ≥1 additional cardiovascular risk factor, grouped into four regions: USA (n = 8144), Canada (n = 3405), Western Europe (Spain, UK, Italy, Sweden, Germany; n = 2048) or ‘other’ (Bulgaria, Israel, Mexico, Czech Republic, Hungary, Poland, Slovakia, Brazil; n = 2879); subgroupings included country and state/province within the USA and Canada. Interventions Randomized to COER™-verapamil or the investigators choice of either atenolol or hydrochlorothiazide, titrated and additional drugs added as required. Main outcome measures Baseline characteristics; blood pressure control, medication adherence and lost-to-follow-up at 2 years; and composite primary endpoint (stroke, myocardial infarction, cardiovascular death) by regional groupings. Results Regional differences were found at baseline for age, gender, blood pressure, percentage receiving antihypertensive drug therapy, initial choice of atenolol or hydrochlorothiazide, and risk factor profile. Blood pressure control rates increased markedly during follow-up in all regions, but varied significantly by region. Blood pressure control, medication adherence and lost-to-follow-up rates were poorest in the USA. After adjustment for baseline differences, the primary-event rate for each region was significantly lower than for the USA. Although baseline factors, blood pressure control and event rates varied by region, treatment differences did not. Conclusion Despite differences in baseline and follow-up measures across geographical regions, the absence of treatment differences by region suggests that the overall findings of CONVINCE are robust.