A randomized phase II trial of apixaban for the prevention of thromboembolism in patients with metastatic cancer

BACKGROUND

Cancer patients receiving chemotherapy are at increased risk for thrombosis. Apixaban, a factor Xa inhibitor, is oral and does not require laboratory monitoring.

OBJECTIVES

A pilot study was conducted to evaluate whether apixaban would be well tolerated and acceptable in cancer patients receiving chemotherapy.

PATIENTS/METHODS

Subjects receiving either first-line or second-line chemotherapy for advanced or metastatic lung, breast, gastrointestinal, bladder, ovarian or prostate cancers, cancer of unknown origin, myeloma or selected lymphomas were randomized to 5 mg, 10 mg or 20 mg once daily of apixaban or placebo in a double-blind manner for 12 weeks. Use of the study drug began within 4 weeks of the start of chemotherapy. The primary outcome was either major bleeding or clinically relevant non-major (CRNM) bleeding. Secondary outcomes included venous thromboembolism (VTE) and grade III or higher adverse events related to the study drug. Thirty-two patients received 5 mg, 30 patients 10 mg, 33 patients 20 mg, and 30 patients placebo. In these groups, there were 0, 0, 2 and 1 major bleeds, respectively. The corresponding data for CRNM bleeds were 1, 1, 2, and 0. The rate of major bleeding in the 93 apixaban patients was 2.2% (95% confidence interval 0.26-7.5%). There were no fatal bleeds. Three placebo patients had symptomatic VTE.

CONCLUSIONS

Apixaban was well tolerated in our study population. These results support further study of apixaban in phase III trials to prevent VTE in cancer patients receiving chemotherapy.

A randomized phase II trial of a new anticoagulant, apixaban, in metastatic cancer

e20514

Background: Cancer patients receiving chemotherapy, biologic, and molecular targeted therapies are at increased risk of venous thromboembolism (VTE). Currently available anticoagulants (ACs) are not well suited to prevent VTE in such patients. Vitamin K antagonist oral ACs require frequent lab monitoring and low molecular weight heparins require daily subcutaneous injection. There is concern for bleeding with ACs. Apixaban (A) is a new antithrombotic agent which inhibits activated coagulation Factor X, is taken orally, and does not require lab monitoring. Trials to prevent post-operative VTE in orthopedic surgery showed that A was effective and safe. We wanted to assess the feasibility of A in cancer. Methods: In a randomized phase II trial, patients with metastatic cancer on 1st or 2nd line chemotherapy received study drug once daily for 12 weeks; either 5, 10 or 20 mg of A, or placebo. The primary outcome measure was the proportion of patients remaining free of major bleeding (MB), clinically relevant non-major bleeding (CRNMB), VTE, and grade ≥3 adverse events considered to be probably/definitely related to study drug (AE*). After 125 patients were recruited, the sponsor eliminated further randomization to the 10 and 20 mg arms, to add experience with the 5 mg dose currently under evaluation for VTE prevention in other conditions. Data on the first 125 patients are reported. Results: The study population was 50% male; 88% had ECOG performance status 0 or 1. The most common cancers were breast, colon, pancreas, and myeloma. 23% had liver metastases. Approximately 80% of A patients completed 12 weeks of treatment. The numbers of patients with events were: Conclusions: Apixiban was well tolerated in patients with advanced cancer on chemotherapy. Major bleeding, thrombosis, and drug-related SAEs were very low. These results support further study of A in phase III trials for VTE prevention in cancer patients.

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Digital assessment of the epicardial electrocardiogram: novel methodology for a core laboratory for clinical studies

BACKGROUND

The epicardial electrocardiogram (ECG) is a sensitive marker for cardiac ischemia and has been used as a measure of ischemia in clinical trials. We sought to examine the utility of a central ECG laboratory for determining ischemic-type ST-segment shifts from epicardial ECG recordings obtained from multiple clinical sites.

HYPOTHESIS

We speculated that an operator-assisted digital ECG core laboratory is feasible, reliable, and efficient, with the ability for rapid and accurate interpretation of the epicardial ECG.

METHODS

The epicardial ECG was recorded via an angioplasty guidewire placed in a coronary artery of a patient undergoing angioplasty. Site investigators visually determined the time-to-onset of 0.1 and 0.3 mm ST-segment elevation, and the maximal ST-segment elevation during balloon inflation, and then compared the measurements with those made at an operator-assisted digital ECG core laboratory.

RESULTS

Agreement between the two methods occurred in 78% of the time-to-onset measurements, but in only 39% of the maximal ST-segment measurements. Overall, the visual measurements of the clinical investigators of time-to-onset differed from the digital core laboratory by 11.8 +/- 11.6 s for 0.1 mV, and 15.8 +/- 20.6 s for 0.3 mV. Recorded maximal ST-segment shifts differed by a mean of 0.47 +/- 0.69 mV.

CONCLUSION

The magnitude of inconsistency between the ECG core laboratory results using an operator-assisted digital method and the interpretations of clinical investigators using manual caliper-type analysis was surprisingly large. These results support the need for an ECG core laboratory in clinical trials where ECG ST-segment shifts are used as a response variable.

Efficacy and safety of the oral direct factor Xa inhibitor apixaban for symptomatic deep vein thrombosis. The Botticelli DVT dose-ranging study

BACKGROUND

Apixaban, an oral potent reversible direct inhibitor of activated factor X, has shown promise in the prevention of venous thromboembolism following major orthopedic surgery. We conducted a dose-ranging study in patients with deep vein thrombosis.

METHODS

Consecutive patients with symptomatic deep vein thrombosis were included and randomized to receive 84-91 days of apixaban 5 mg twice-daily, 10 mg twice-daily, or 20 mg once-daily, or low molecular weight heparin (LMWH) followed by a vitamin K antagonist (VKA). The primary efficacy outcome was the composite of symptomatic recurrent venous thromboembolism and asymptomatic deterioration of bilateral compression ultrasound or perfusion lung scan. The principal safety outcome was the composite of major and clinically relevant, non-major bleeding.

RESULTS

The mean age of the 520 included patients was 59 years, and 62% were male. The primary outcome occurred in 17 of the 358 apixaban-treated patients [4.7%, 95% confidence interval (CI) 2.8-7.5%] and in five of the 118 LMWH/VKA-treated patients (4.2%, 95% CI 1.4-9.6%) who were evaluable. The incidence in all three apixaban groups was low and comparable without evidence of a dose response. The principal safety outcome occurred in 28 (7.3%) of the 385 apixaban-treated patients and in 10 (7.9%) of the 126 LMWH/VKA-treated patients. No dose response for apixaban was observed.

CONCLUSION

These observations warrant further evaluation of apixaban in phase III studies. The attractive fixed-dose regimen of this compound may meet the demand to simplify anticoagulant treatment in patients with established venous thromboembolism.

The efficacy and safety of apixaban, an oral, direct factor Xa inhibitor, as thromboprophylaxis in patients following total knee replacement

BACKGROUND

Heparins and warfarin are currently used as venous thromboembolism (VTE) prophylaxis in surgery. Inhibition of factor (F) Xa provides a specific mechanism of anticoagulation and the potential for an improved benefit-risk profile.

OBJECTIVES

To evaluate the safety and efficacy of apixaban, a potent, direct, oral inhibitor of FXa, in patients following total knee replacement (TKR), and to investigate dose-response relationships.

PATIENTS/METHODS

A total of 1238 patients were randomized to one of six double-blind apixaban doses [5, 10 or 20 mg day(-1) administered as a single (q.d.) or a twice-daily divided dose (b.i.d.)], enoxaparin (30 mg b.i.d.) or open-label warfarin (titrated to an International Normalized Ratio of 1.8-3.0). Treatment lasted 10-14 days, commencing 12-24 h after surgery with apixaban or enoxaparin, and on the evening of surgery with warfarin. The primary efficacy outcome was a composite of VTE (mandatory venography) and all-cause mortality during treatment. The primary safety outcome was major bleeding.

RESULTS

A total of 1217 patients were eligible for safety and 856 patients for efficacy analysis. All apixaban groups had lower primary efficacy event rates than either comparator. The primary outcome rate decreased with increasing apixaban dose (P = 0.09 with q.d./b.i.d. regimens combined, P = 0.19 for q.d. and P = 0.13 for b.i.d. dosing).A significant dose-related increase in the incidence of total adjudicated bleeding events was noted in the q.d. (P = 0.01) and b.i.d. (P = 0.02) apixaban groups; there was no difference between q.d. and b.i.d. regimens.

CONCLUSIONS

Apixaban in doses of 2.5 mg b.i.d. or 5 mg q.d. has a promising benefit-risk profile compared with the current standards of care following TKR.

The hemodynamic effects of long-term ACE inhibition with fosinopril in patients with heart failure. Fosinopril Hemodynamics Study Group

The objective of this study was to evaluate the hemodynamic and clinical effects of fosinopril in patients with heart failure. This was a prospective, multicenter, double-blind, randomized, parallel-group study. Patients 18 to 80 years of age who were receiving diuretics with a systolic blood pressure (SBP) > or = 90 mm Hg, New York Heart Association (NYHA) functional class II-IV, left ventricular ejection fraction < or = 40%, pulmonary capillary wedge pressure (PCWP) > or = 18 mm Hg, and a cardiac index (CI) < or = 2.6 L/min/m(2) were eligible. A total of 179 patients were randomized to a single, double-blind oral dose of placebo or fosinopril at 1, 20, or 40 mg, and hemodynamic monitoring was performed for 24 hours postdose; 155 patients with SBP > or = 90 mm Hg were re-randomized to 10 weeks of double-blind fosinopril at 1, 20, or 40 mg once daily. Hemodynamic monitoring was repeated at the last visit, beginning at 24 hours postdose (trough) and continuing for 12 hours thereafter. Significant decreases in preload (PCWP) and afterload (mean arterial blood pressure [MABP] and systemic vascular resistance [SVR]) were evident 3 to 4 hours after a single dose of fosinopril at 20 and 40 mg and continuing for up to 8 to 12 hours postdose for PCWP and SVR and for up to 24 hours postdose for MABP (P < or = .05 v placebo and baseline). Sustained decreases in PCWP, MABP, SVR, and heart rate and increases in CI and stroke volume index were observed after 10 weeks of treatment with fosinopril at 20 and 40 mg once daily (P < or = .05 v 1 mg group for PCWP and MABP at most time points and P < or = .05 v baseline for other parameters at most time points). Dose-related trends toward reduced supplemental diuretic use (P = .027) and reduced symptoms of dyspnea (P = .008) were observed with the 20-mg and 40-mg fosinopril dose groups. Once daily administration of fosinopril at 20 and 40 mg was safe and well tolerated, provided a sustained beneficial hemodynamic effect, improved left ventricular performance, and reduced symptoms of dyspnea, resulting in a reduced need for supplemental diuretic therapy.

Effects of fosinopril on exercise tolerance, symptoms, and clinical outcomes in patients with decompensated heart failure

The purpose of this prospective, multicenter, randomized, double blind, placebo controlled study was to determine the clinical effects of fosinopril in patients with decompensated or worsening heart failure (HF). Patients >/=18 years with New York Heart Association (NYHA) functional class II-IV HF who had been hospitalized or seen in the ER or outpatient clinic for treatment of worsening or decompensated HF were eligible. Patients had to be on diuretic therapy and have a left ventricular ejection fraction (LVEF) </=35% and a treadmill exercise tolerance test (ETT) duration of </=8 minutes. Randomized patients began 12 weeks of fosinopril 10 mg (or placebo) qAM and were titrated within 4 weeks to fosinopril 20 mg and then to 40 mg (or placebo) qAM (if seated, systolic blood pressure (SBP) >/=90 mm Hg). ETTs (modified Naughton protocol) were performed at weeks 1, 3, 6, and 12. A total of 206 patients (mean age 62 years) were randomized to fosinopril (n=102) or placebo (n=104). Most patients were NYHA functional class III (58%) or IV (30%) at presentation; 145 patients completed 12 weeks of treatment (fosinopril, n=85; placebo, n=60). After adjustment for baseline imbalances and investigator effects, fosinopril-treated patients had a 513 second mean exercise duration at endpoint vs. a 489 second duration in placebo-treated patients (p=0.353). When the analysis was adjusted for the impact of dropouts on ETT time, fosinopril-treated patients had a greater exercise duration than those treated with placebo (p=0.043). Fewer patients in the fosinopril group were discontinued from study medication (p=0.008) or hospitalized (p=0.005) for worsening HF. At endpoint, more patients improved their NYHA Functional Class and fewer had worsened with fosinopril vs. placebo (p=0.018); fosinopril-treated patients showed improvements in dyspnea (p=0.054), fatigue (p=0.052), edema (p=0.012), and paroxysmal nocturnal dyspnea (p=0.003) vs. the placebo group. Once-daily fosinopril had a favorable effect on dropout-adjusted exercise tolerance, reduced the frequency of discontinuations or hospitalizations for worsening HF, improved HF signs and symptoms, and was safe and well tolerated. (c)1999 by CHF, Inc.

Recombinant human superoxide dismutase (h-SOD) fails to improve recovery of ventricular function in patients undergoing coronary angioplasty for acute myocardial infarction

BACKGROUND

Animal studies have demonstrated a burst of oxygen free radical generation after reperfusion of ischemic myocardium that could be blocked by administration of the free radical scavenger recombinant human superoxide dismutase (h-SOD). A multicenter, randomized, placebo-controlled clinical trial was designed to test the hypothesis that free radical-mediated reperfusion injury could be reduced by intravenous administration of h-SOD begun before percutaneous transluminal coronary angioplasty (PTCA) in patients with acute transmural myocardial infarction.

METHODS AND RESULTS

One hundred twenty patients were randomized to receive placebo (n = 59) or h-SOD (n = 61) given as a 10-mg/kg intravenous bolus followed by a 60-minute infusion of 0.2 mg.kg-1.min-1. Left ventricular function was analyzed via paired contrast left ventriculograms performed before PTCA and after 6 to 10 days and paired radionuclide ventriculograms performed within 24 hours of PTCA and after 4 to 6 weeks. Both h-SOD- and placebo-treated patients showed improvement in global and regional left ventricular function after successful reperfusion. Compared with the placebo group, no additional improvement was observed in the patients treated with h-SOD.

CONCLUSIONS

The results of this clinical trial failed to demonstrate a beneficial effect of h-SOD on global or regional left ventricular function in patients who underwent successful PTCA for treatment of acute myocardial infarction.

Clinical safety profile of sotalol in the treatment of arrhythmias

The safety of sotalol was evaluated in 3,257 patients treated for cardiac arrhythmias in double-blind and open-label clinical trials that support United States registration of the drug. In this composite population, 80% of patients had structural heart disease and 42% had life-threatening ventricular arrhythmias, i.e., ventricular tachycardia (VT) or fibrillation (VF). Proarrhythmia was reported in 141 patients (4.3%). Of these, 78 (2.4%) had torsades de pointes and 26 (0.8%) had sustained VT or VF. The overall incidence was higher in patients treated for sustained VT or VF (6.5%). In these patients, serious proarrhythmia was predominantly torsades de pointes (4.1%) and was more prevalent in patients with congestive heart failure and low ejection fraction. Torsades de pointes was observed early in the course of treatment, and its occurrence was related to dose. The overall mortality in patients treated with sotalol was 4.3% (139 patients); in patients with life-threatening arrhythmias, cardiac mortality was 4.8%. In only 27 patients (0.8%) was the death thought to be potentially drug-related. The deaths were not related to dose. Data from a previously reported placebo-controlled postmyocardial infarction trial indicated no significant difference in mortality between sotalol and placebo. Heart failure was reported in 3.3% of patients and was most prevalent in those with a previous history of congestive heart failure, cardiomyopathy, or structural heart disease. The occurrence of heart failure was unrelated to dose or time on drug; in more than half of the patients, sotalol treatment was continued. On average, there was no decrease in ejection fraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of oral sotalol on systemic hemodynamics and programmed electrical stimulation in patients with ventricular arrhythmias and structural heart disease

We explored the central hemodynamic responses to oral sotalol during dose titration in patients with ventricular arrhythmias who underwent programmed ventricular stimulation. Twelve patients were included in the study, 9 with a history of sustained ventricular tachyarrhythmias (6 postmyocardial infarction and 3 with cardiomyopathy) and 3 with a history of nonsustained ventricular tachycardia postmyocardial infarction. Left ventricular ejection fractions were < 45% in 10 patients, and < 35% in 5; the mean ejection fraction was 37% (range 20-51%). Sotalol prevented the induction of ventricular tachycardia in each of 3 patients with nonsustained ventricular tachycardia and in 6 of 9 with sustained ventricular tachycardia at baseline study. At peak action (2 hours) after sotalol loading (mean dose, 167 mg orally twice daily), the hemodynamic effects included bradycardia, decreased cardiac index, increased left ventricular filling pressure and systemic vascular resistance, and no change in stroke volume or stroke work index. One patient was not continued on sotalol, owing to an excessive increase in the pulmonary capillary wedge pressure, despite the lack of symptomatic heart failure. Congestive heart failure in association with marked bradycardia developed in another patient, who had suppression of inducible ventricular tachycardia after sotalol loading; this patient was managed with a reduction in the dose of sotalol and a regimen of digoxin and furosemide, and has been well compensated and without a recurrence of sustained ventricular tachycardia for more than 4 years. Ventricular tachycardia has been controlled with sotalol, without hemodynamic deterioration, in 6 of these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Beta-blockade with bucindolol in heart failure caused by ischemic versus idiopathic dilated cardiomyopathy

BACKGROUND

We investigated the effects of bucindolol, a nonselective, non-ISA beta-blocker with mild-vasodilatory properties, in patients with congestive heart failure from ischemic dilated cardiomyopathy (ISCDC, n = 27) and compared the results with those in subjects with heart failure from idiopathic dilated cardiomyopathy (IDC, n = 22).

METHODS AND RESULTS

Patients were randomized in a double-blind fashion to receive 12 weeks' treatment with either bucindolol or placebo, with randomization stratified for IDC or ISCDC: Invasive (right heart catheterization) and noninvasive (echo, MUGA, central venous norepinephrine, exercise treadmill studies, and symptom scores) tests of heart failure severity were determined at baseline and end of the study. For all subjects (ISCDC plus IDC), relative to placebo treatment, bucindolol-treated patients had significant improvement in ejection fraction, left ventricular size and filling pressure, stroke work index, symptom score, and central venous norepinephrine. However, most of these differences could be attributed to improvement in the IDC subgroup, as the only parameter with a statistically significant degree of improvement in the bucindolol-treated ISCDC subgroup was left ventricular size.

CONCLUSIONS

We conclude that beta-blockade may produce quantitatively different degrees of response in different kinds of heart muscle disease.

Long-term (2 year) beneficial effects of beta-adrenergic blockade with bucindolol in patients with idiopathic dilated cardiomyopathy

Beta-adrenergic blockade represents a promising therapeutic approach to idiopathic dilated cardiomyopathy. Bucindolol, a new beta-blocker, showed favorable effects in a short-term (3 month) trial in idiopathic dilated cardiomyopathy. To assess long-term response, 20 study patients (7 of 9 patients previously assigned to the placebo group and 13 of 14 patients previously assigned to bucindolol therapy) received long-term bucindolol therapy and were followed up for a mean of 23 +/- 4 months (range 17 to 30). The mean patient age was 49 years (range 29 to 66) and the median duration of disease was 11 months (range 1 to 190). Ten patients were in functional class II and 10 were in class III; 15 patients were men. At the end of the common follow-up time, all 20 patients were alive, 17 continued to receive bucindolol (mean dose 176 mg/day, range 25 to 200), and 2 underwent cardiac transplantation. Left ventricular ejection fraction increased from a baseline value of 25 +/- 8% to 35 +/- 13% (n = 19 pairs, p less than 0.001). Functional class improved in 12, was unchanged in 5 and deteriorated in 3 (p = 0.056). Exercise time was maintained (9.4 +/- 3.1 versus 9.1 +/- 3.5 min, n = 19, p = NS), as was maximal oxygen uptake (19.2 +/- 4.9 versus 18.8 +/- 5.7 ml/kg per min, n = 19, p = NS). Thus, long-term bucindolol therapy leads to substantial increases in ejection fraction and to improved functional class while stable exercise performance is maintained.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of bucindolol on neurohormonal activation in congestive heart failure

To examine the effects of beta-adrenergic blockade on neurohormonal activation in patients with congestive heart failure, 15 men had assessments of hemodynamics and supine peripheral renin and norepinephrine levels before and after 3 months of oral therapy with bucindolol, a nonselective beta antagonist. At baseline, plasma renin activity did not correlate with any hemodynamic parameter. However, norepinephrine levels had a weak correlation with left ventricular end-diastolic pressure (r = 0.74, p less than 0.01), stroke volume index (r = 0.61, p less than 0.02) and pulmonary vascular resistance (r = 0.54, p less than 0.05). Plasma renin decreased with bucindolol therapy, from 11.6 +/- 13.4 to 4.3 +/- 4.1 ng/ml/hour (mean +/- standard deviation; p less than 0.05), whereas plasma norepinephrine was unchanged, from 403 +/- 231 to 408 +/- 217 pg/ml. A wide diversity of the norepinephrine response to bucindolol was observed with reduction of levels in some patients and elevation in others. Although plasma norepinephrine did not decrease, heart rate tended to decrease (from 82 +/- 20 vs 73 +/- 11 min-1, p = 0.059) with beta-adrenergic blockade, suggesting neurohormonal antagonism at the receptor level. No changes in I-123 metaiodobenzylguanidine uptake occurred after bucindolol therapy, suggesting unchanged adrenergic uptake of norepinephrine with beta-blocker therapy. Despite reductions in plasma renin activity and the presence of beta blockade, the response of renin or norepinephrine levels to long-term bucindolol therapy did not predict which patients had improved in hemodynamic status (chi-square = 0.37 for renin, 0.82 for norepinephrine).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of beta-adrenergic blockade on myocardial function and energetics in congestive heart failure. Improvements in hemodynamic, contractile, and diastolic performance with bucindolol

The hemodynamic effects of beta-adrenergic blockade with bucindolol, a nonselective beta-antagonist with mild vasodilatory properties, were studied in patients with congestive heart failure. Fifteen patients (New York Heart Association class I-IV) underwent cardiac catheterization before and after 3 months of oral therapy with bucindolol. The left ventricular ejection fraction increased from 0.23 +/- 0.12 to 0.29 +/- 0.14 (p = 0.007), and end-systolic elastance, a relatively load-independent determinant of contractility, increased from 0.60 +/- 0.40 to 1.11 +/- 0.45 mm Hg/ml (p = 0.0049). Both left ventricular stroke work index (34 +/- 13 to 47 +/- 19 g-m/m2, p = 0.0059) and minute work (5.5 +/- 2.2 to 7.0 +/- 2.6 kg-m/min, p = 0.0096) increased despite reductions in left ventricular end-diastolic pressure (19 +/- 8 to 15 +/- 5 mm Hg, p = 0.021). There was an upward shift in the peak + dP/dtmax-end-diastolic volume relation (p = 0.0005). These data demonstrate improvements in myocardial contractility after beta-adrenergic blockade with bucindolol. At a matched paced heart rate of 98 +/- 15 min-1, the time constant of left ventricular isovolumic relaxation was significantly reduced by bucindolol therapy (92 +/- 17 versus 73 +/- 11 msec, p = 0.0013), and the relation of the time constant to end-systolic pressure was shifted downward (p = 0.014) with therapy. The slope of the logarithm left ventricular end-diastolic pressure-end-diastolic volume relation was unchanged (p = 0.51) after bucindolol. These data suggest that chronic beta-adrenergic blockade with bucindolol improves diastolic relaxation but does not alter myocardial chamber stiffness. Myocardial oxygen extraction, consumption, and efficiency were unchanged despite improvement in contractile function and mechanical work. Thus, in patients with congestive heart failure, chronic beta-adrenergic blockade with bucindolol significantly improves myocardial contractility and minute work, yet it does not do so at the expense of myocardial oxygen consumption. Additionally, bucindolol improves myocardial relaxation but does not affect chamber stiffness.

Long-term beta-blocker vasodilator therapy improves cardiac function in idiopathic dilated cardiomyopathy: a double-blind, randomized study of bucindolol versus placebo

PURPOSE

Bucindolol is a potent nonselective beta-blocking agent with vasodilatory properties. In this study, we evaluated the effects of long-term bucindolol therapy in the treatment of heart failure from idiopathic dilated cardiomyopathy.

PATIENTS AND METHODS

Patients were eligible for enrollment if they had symptomatic heart failure, idiopathic dilated cardiomyopathy, and left ventricular ejection fraction less than 0.40. All patients received an initial test dose of 12.5 mg bucindolol orally every 12 hours for two or three doses. Patients tolerating the test dose were randomly assigned (double-blind) to receive bucindolol or placebo in a 3:2 ratio. Study medication was begun at a dose of 12.5 mg orally every 12 hours and gradually increased over a 1-month period until either a maximum tolerated dose or a target dose of 100 mg every 12 hours was reached. Study medication was then continued for an additional 2 months.

RESULTS

A total of 24 patients were enrolled into the study. Twenty-three patients tolerated bucindolol test challenge; 14 were randomized to receive bucindolol, and nine were randomly assigned to receive placebo. The placebo group (age 56 +/- 2 years) was significantly older than the bucindolol group (46 +/- 3 years), but by all other clinical and hemodynamic parameters the two groups were comparable. Twenty-two of 23 patients completed the study. Patients treated with bucindolol had significant improvements in clinical heart failure symptoms and in resting hemodynamic function, including an increase of left ventricular ejection fraction (0.26 +/- 0.02 to 0.35 +/- 0.09, p = 0.003), cardiac index (2.2 +/- 0.1 to 2.5 +/- 0.4 L/minute/m2, p = 0.014), and left ventricular stroke work index (25 +/- 3 to 35 +/- 7 g.m/m2, p = 0.002) and a decrease in pulmonary artery wedge pressure (17 +/- 3 to 10 +/- 5 mm Hg, p = 0.005) and heart rate (86 +/- 3 to 75 +/- 9 beats/minute, p = 0.012). Patients treated with bucindolol also had a significant increase in exercise left ventricular ejection fraction (0.26 +/- 0.03 to 0.32 +/- 0.14, p = 0.015) and reduction in questionnaire-measured symptoms (p = 0.007) and New York Heart Association functional class (p less than 0.001). However, total treadmill exercise duration and maximal oxygen consumption with exercise did not change. No changes in rest or exercise parameters were observed in the placebo-treated group. Central venous plasma norepinephrine concentration decreased significantly in the bucindolol-treated group (423 +/- 79 to 212 +/- 101 pg/mL, p = 0.010), but was unchanged in the placebo-treated group.

CONCLUSION

Bucindolol is well tolerated in patients with idiopathic dilated cardiomyopathy and congestive heart failure, and therapy for 3 months is associated with improved resting cardiac function, improved heart failure symptoms, and a reduction in venous norepinephrine concentration.

Efficacy of bucindolol in systemic hypertension

The hemodynamic effects of oral bucindolol, a non-selective beta-adrenergic blocking agent with intrinsic sympathomimetic activity and direct vasodilating properties, were studied at rest and during handgrip exercise with a flotation-directed pulmonary artery catheter in 12 patients with mild to moderate essential hypertension. After the initial dose of 150 mg of bucindolol, blood pressure (BP) was significantly reduced and cardiac output was increased (from 5.9 +/- 0.8 to 6.8 +/- 1.6 liters/min) in the supine position and during exercise (p less than 0.05). Systemic vascular resistance was reduced (from 1,555 +/- 339 to 1,311 +/- 467 dynes s cm-5, p less than 0.01) at rest and without significant changes during exercise. There were increases in heart rate (13 +/- 13%, p less than 0.01) and right atrial (69 +/- 77%, p less than 0.05), pulmonary arterial (38 +/- 24 %, p less than 0.001) and pulmonary artery wedge pressures (62 +/- 46%, p less than 0.001) during exercise. Bucindolol did not change these variables at rest or during exercise. Bucindolol increased plasma norepinephrine levels both at rest (from 330 +/- 151 to 588 +/- 320 ng/liter, p less than 0.01) and during exercise (from 468 +/- 220 to 685 +/- 390 ng/liter, p less than 0.05). After 4 weeks of bucindolol with doses of 50 to 200 mg 3 times daily, BP was reduced in both supine and standing positions (mean arterial BP of 11 +/- 7% [p less than 0.001] and 11 +/- 6% [p less than 0.001], respectively), without changes in cardiac output, systemic vascular resistance or plasma norepinephrine level.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic effects during rest and exercise of bucindolol in hypertensive men

Bucindolol is an investigational beta-adrenergic blocking agent with intrinsic sympathomimetic and vasodilatory activity in animals. In a double-blind, six-way, crossover study of six mild-to-moderate hypertensive men, the effects of bucindolol 100, 200, and 300 mg/d on resting blood pressure, heart rate, forearm blood flow, and vascular resistance measured by pneumoplethysmography, and blood pressure and heart rate after cycle and handgrip exercise were compared with those of propranolol 160 and 320 mg/d and placebo after q12h administration for five doses. Both bucindolol and propranolol significantly suppressed heart rate after cycle exercise in comparison with placebo (-33 to -48 beats/min), demonstrating beta blockade. Suppression of resting heart rate by propranolol (-20 beats/min) was significantly (P less than .05) greater than bucindolol (-7 to -8 beats/min); a similar treatment difference in heart rate was noted after handgrip exercise (-18 to -19 vs -1 to -8 beats/min, respectively). Bucindolol and propranolol decreased resting blood pressure to the same extent (in comparison with placebo; P less than .05 at peak activity, 2 hr postdose). Bucindolol tended to increase forearm blood flow and decrease forearm vascular resistance (P less than .05 at 4 hr postdose) in comparison with placebo. The effect of propranolol on forearm blood flow and forearm vascular resistance was not significant compared with placebo. These data are consistent with intrinsic sympathomimetic and vasodilatory activity of bucindolol in hypertensive men.

Cardiovascular and renal effects of buspirone in several animal models

Intravenous administration (0.3 or 3 mg/kg) of buspirone to anesthetized rats elicited a transient pressor response (14 +/- 2 mmHg) and sustained bradycardia. However, oral administration (30 mg/kg) reduced the blood pressure and heart rate of conscious normotensive (-14 +/- 4 mmHg) and DOCA-salt hypertensive rats (-22 +/- 5 mmHg). Buspirone (3-100 mg/kg, p.o.) elicited increases in urinary volume and electrolyte excretion of conscious normotensive rats and decreased these parameters in conscious mice. Buspirone was observed to possess alpha 1-adrenoceptor agonist activity in ganglion-blocked anesthetized rats. Buspirone (0.3-3 mg/kg, i.v.) elicited transient elevations in the blood pressure of open-chest anesthetized dogs. There was a sustained increase in total peripheral resistance and a decrease in aortic blood flow, heart rate, right ventricular contractile force and left ventricular dp/dt max. Intravenous and oral administration to anesthetized and conscious dogs elevated urinary volume and electrolyte excretion. However, the doses used to elicit the observed alterations in hemodynamic/renal function are considerably greater than those which produce anxiolytic effects. Thus, it is doubtful that anxiolytic doses of buspirone will produce cardiovascular alterations in patients.

Selectivity of the intrinsic sympathomimetic activity of the beta-adrenergic blocking drug bucindolol

We studied the comparative effects of beta-adrenergic blockade with propranolol (PROP) and bucindolol (BUC), a beta-adrenergic agonist having both alpha-adrenergic blocking properties and intrinsic sympathomimetic activity (ISA) on airway and cardiovascular responses, in 38 mongrel dogs in situ. Intravenous infusion of 0.6 mg/kg + 6 micrograms/kg/min BUC and 2.0 mg/kg + 20 micrograms/kg/min PROP caused identical shifts in the isoproterenol (ISO) EC50 for chronotropic and hypotensive arterial blood pressure responses. After PROP administration, resting heart rate (HR) decreased from 188 +/- 15 to 142 +/- 12 beats/min (p less than 0.02); BUC caused no decrease in HR. In contrast, the effects of BUC and PROP on mean arterial blood pressure response to ISO were similar. No change in bronchomotor tone was observed after bolus injection of either BUC or PROP. Beta-Adrenergic relaxation to ISO and alpha-adrenergic contraction to norepinephrine (NE) were studied simultaneously in tracheal and bronchial airways using chronotropically equivalent beta-adrenoceptor blocking doses of PROP and BUC. Comparable inhibition of ISO-induced airway relaxation after contraction with 120 micrograms/kg/min i.v. serotonin was demonstrated in both PROP (n = 5) and BUC (n = 5) groups (p less than 0.01 for doses greater than 5 X 10(-11) mol/kg). Similarly, both BUC (n = 5) and PROP (n = 5) blocked beta-adrenergic relaxation and caused identical alpha-adrenergic airway contraction to intravenous NE. We conclude that the ISA of the beta-adrenergic blocking drug BUC can be demonstrated on the spontaneous rate of the heart but not on the activity of bronchial smooth muscle. BUC neither augments ISO-induced relaxation nor inhibits NE-induced contraction of airways after effective chronotropic blockade.

Beneficial effects of bucindolol in a canine model of pentobarbital-induced heart failure

Heart failure was induced in barbital-anesthetized dogs by administering high doses of pentobarbital. This procedure depresses cardiac function as indicated by a reduction in right ventricular contractile force (RVCF), left ventricular dp/dt and aortic blood flow. Bucindolol (0.1 mg/kg and 0.1 mg/kg/hr) elicited a pronounced and prolonged stimulant effect on these depressed indicators of cardiac function. Both RVCF and aortic blood flow returned to pre-failure levels, left ventricular dp/dt increased 43% but heart rate was elevated only slightly (14%). Total peripheral resistance was lowered 36% by bucindolol. The combination of myocardial stimulation and vasodilatation which contributed to the positive results in this acute model of pump failure suggests a possible role for bucindolol in the clinical management of congestive heart failure. Further these results suggest that bucindolol, in contrast to propranolol, could also be used in a sub-group of hypertensive patients with depressed cardiac function.

Cardiovascular effects of bucindolol (MJ 13105) in conscious dogs

Bucindolol (MJ 13105), administered to conscious, normotensive dogs (a) attenuated the positive chronotropic and diastolic depressor response elicited by isoproterenol, (b) increased heart rate and (c) elevated plasma renin activity (PRA). Repeated daily administration of bucindolol caused a cumulative reduction in isoproterenol-elicited cardiac and vascular responses. The increase in heart rate was not blocked by atropine and only partially attenuated by propranolol. To study the effect of bucindolol on erect blood pressure, dogs were tilted rapidly through 90 degrees from the supine to a head-up erect position, a maneuver that reflexly increases blood pressure. Following the administration of bucindolol, blood pressure in the erect position was lower than before drug but was still higher than blood pressure in the supine position suggesting the compensatory reflex response to this postural change is still functional. Bucindolol had no significant effect on P wave and QRS durations or P-R and corrected Q-T intervals of the EKG.

The ganglion-blocked, angiotensin II-supported rat: a model for demonstrating antihypertensive vasodilator activity

This report describes the implementation of an in vivo method for demonstrating direct vasodilator activity of potential antihypertensive agents. The experimental model is an anesthetized, ganglion-blocked rat whose blood pressure is maintained by an intravenous infusion of angiotensin II. A hypotensive response in this model appears to correlate more closely with antihypertensive activity in desoxycorticosterone acetate (DOCA)-salt hypertensive rats than does a vasodilator response in the pump-perfused hind limb of anesthetized dogs. Furthermore, it distinguishes between vasodilators that are effective in hypertension, eg hydralazine and diazoxide, and vasodilators that are used to treat peripheral vascular disease, eg cinnarizine and papaverine.

Antihypertensive indole derivatives of phenoxypropanolamines with beta-adrenergic receptor antagonist and vasodilating activity

A series of 25 aryloxypropanolamines containing the 3-indolyl-tert-butyl [i.e., 1,1-dimethyl-2-(1H-indol-3-yl)ethyl] or substituted 3-indolyl-tert-butyl moiety as the N substituent is reported. These compounds have been tested for antihypertensive activity in spontaneously hypertensive rats (SHR), beta-adrenergic receptor antagonist action in conscious normotensive rats, vasodilating activity in ganglion-blocked rats with blood pressure maintained by angiotensin II infusion, and for intrinsic sympathomimetic action (ISA) in reserpinized rats. Some of the compounds exhibit antihypertensive activity in combination with beta adrenergic receptor antagonist and vasodilating action. The structure--activity relationships in these tests are discussed.