Safety of binodenoson, a selective adenosine A2A receptor agonist vasodilator pharmacological stress agent, in healthy subjects with mild intermittent asthma.

BACKGROUND: The pharmacological stress agents adenosine and dipyridamole are contraindicated in asthma patients because of the risk of adenosine receptor-mediated bronchospasm. Binodenoson, a selective adenosine A(2A) receptor agonist, produces maximal coronary hyperemia during pharmacological stress testing yet has a low affinity for the adenosine A(1), A(2B), and A(3) receptors that are probably responsible for bronchospasm. This study was conducted to assess the safety of binodenoson in 87 healthy young adult volunteers with documented mild, intermittent asthma. METHODS AND RESULTS: This study consisted of a dose-escalating, single-blinded phase and a placebo-controlled, double-blinded phase conducted in healthy, young adults with documented mild, intermittent, asthma. In the single-blinded phase, 3 sequential cohorts of 8 subjects received intravenous binodenoson (0.5, 1.0, and 1.5 microg/kg). In the double-blinded phase, commenced after medical review of results from the single-blinded phase, subjects were randomly assigned 2:1 to either binodenoson 1.5 microg/kg (n=41) or placebo (n=22). The primary end point was clinically significant bronchoconstriction, defined as a decrease in forced expiratory volume in 1 second of >/=20% from the preinjection measure. Secondary safety end points were changes from preinjection measure in forced expiratory volume in 1 second, forced vital capacity, and forced expiratory flow during the middle 50% of the forced vital capacity; vital signs; pulse oximetry; and adverse events. Binodenoson caused no clinically significant bronchoconstriction or alterations in pulmonary function parameters and transiently increased heart rate and systolic blood pressure. The most common treatment-emergent adverse events were tachycardia, dizziness, and flushing. CONCLUSIONS: Binodenoson was safe, well tolerated, and caused no clinically significant bronchoconstriction or pulmonary responses in a small population of healthy subjects with mild, intermittent asthma.

Modified visual analog scale symptom-intensity and overall-bother measures for the assessment of symptoms in studies of pharmacologic stress agents.

BACKGROUND: Drugs used to induce stress for cardiac imaging studies often cause discomfort. Patient-reported intensity of discomfort should be considered when comparing such agents. OBJECTIVE: The purpose of this study was to assess the psychometric properties of a modified visual analog scale (VAS) symptom-intensity measure and an overall-bother measure adapted to assess patient-reported intensity of the adverse events (AEs) associated with pharmacologic stress testing with adenosine, a pharmacologic stress myocardial perfusion imaging (PS-MPI) agent. METHODS: Data were based on 2 complementary, open-label, multicenter, naturalistic, observational studies among patients completing a PS-MPI procedure. Content, concurrent, and discriminant validity was examined by correlating modified VAS symptom-intensity scores obtained from patients with investigator-rated intensity at time of event, overall bother, and patient-reported measures obtained during a structured interview. Test-retest reliability of the overall-bother measure was examined using 1- and 2-hour assessments, and concurrent validity was assessed by correlating counts of symptoms and other patient-reported measures. Responsiveness was examined by calculating change scores of the VAS symptom-intensity measures from baseline to 1 hour among patients who reported symptoms during the 1-hour monitoring period after PS infusion. Low to moderate correlation was defined as a coefficient between 0.3 and 0.5. RESULTS: A total of 324 patients enrolled in the 2 studies. Content validity of the VAS symptom-intensity and overall-bother measures was established, with nearly all patients reporting that they were a useful way to rate symptom intensity and overall bother. VAS ratings were moderately to highly correlated with physician-rated AE intensity, and patient-reported assessments of symptom intensity, discomfort, and concern (r(s) = 0.21 r(s) = 0.84). Findings to support discriminant validity were inconclusive because of small sample size. Responsiveness was demonstrated with VAS symptom-intensity change scores ranging from 2.8 for headache to 4.9 for chest pain; effect sizes for these differences were large, ranging from 1.6 to 7.3, respectively. CONCLUSION: Findings support the validity, reliability, and responsiveness of the modified VAS symptom-intensity measure, and the reliability and validity of the overall-bother measure for use in patients completing PS procedures.

Design, rationale, and populations of an international outcomes and utilization study of pharmacologic stress SPECT myocardial perfusion imaging in contemporary practice.

BACKGROUND: A prospective, international, multicenter, observational study was conducted to investigate patient and population characteristics; utilization of radiopharmaceuticals and pharmacologic stress (PS) agents; imaging protocols; clinical outcomes; the incidence, intensity, and time to onset of adverse events; and the prognostic value of single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) procedures. The rationale, study methods, and data on presenting populations are described. METHODS AND RESULTS: Investigators recorded the demographics, American College of Cardiology/American Heart Association pretest likelihood for coronary artery disease, cardiovascular risk factors, antianginal drug use, use of PS agents and associated adverse events, and radiopharmaceutical(s) and imaging protocol for each patient enrolled. SPECT images were reconstructed at each site; investigators assigned summed stress and summed rest scores using a 17-segment model (rating perfusion on a scale ranging from 0 to 4). Patients were followed up for 1 year for clinical outcomes of revascularization, nonfatal myocardial infarction, or death. CONCLUSION: The design offers a unique opportunity to study the characteristics of patients referred for SPECT imaging over a period of time consistent with the laboratories' usual practices, provides an up-to-date PS safety registry, and allows assessment of the prognostic value of PS SPECT MPI across a wide number of covariables, as well as relationships between patient and population characteristics, SPECT MPI results, and clinical outcomes.

Coronary circulation responses to binodenoson, a selective adenosine A2A receptor agonist.

The purpose of this study was to define binodenoson dosing regimens that produce coronary hyperemia comparable to those of adenosine and that are tolerated well by patients. An open-label, randomized, parallel-group, multicenter study enrolled adult patients who had completed diagnostic cardiac catheterization. Coronary blood flow velocity (CBFV) was measured with a Doppler flow wire, and CBFV reserve was determined before binodenoson administration. Patients (n = 133) received a 3-minute infusion of 0.3, 0.5, or 1 microg/kg/min or a bolus intravenous injection of 1.5 or 3 microg/kg. Coronary hyperemic responses were evident within seconds of administering binodenoson, and the magnitudes and durations of coronary hyperemic responses were dose related. The 1.5- and 3-microg/kg doses, by infusion or bolus, produced maximal coronary hyperemia equivalent to CBFV reserve. All doses transiently decrease blood pressure and increased heart rate and rate-pressure product. In conclusion, the 1.5-microg/kg binodenoson bolus dose produced nearly maximal coronary hyperemia by 4.5 +/- 3.7 minutes that was sustained for 7.4 +/- 6.86 minutes, was accompanied by modest changes in blood pressure, heart rate, and rate-pressure product, and produced no adverse changes on electrocardiogram, including no second- or third-degree atrioventricular block.

Pharmacokinetics and safety of binodenoson after intravenous dose escalation in healthy volunteers.

BACKGROUND: Binodenoson, a highly selective agonist of the adenosine A 2A receptor, is being developed as a short-acting coronary vasodilator as an adjunct to radiotracers for use in myocardial stress imaging. This study was designed to assess the single-dose pharmacokinetics, safety, and tolerability of intravenous binodenoson. METHODS AND RESULTS: This was a single-center, open-label, nonrandomized, dose-escalation study in 24 healthy volunteers. Each subject received 3 successive intravenous doses of binodenoson (0.1, 0.2, 0.4, 0.6, 1, 2, 3, 4, 5, and 6 microg/kg), each infused over a period of 10 minutes and separated by washout periods of at least 120 minutes. Generally, binodenoson was well tolerated. There were no serious adverse events. However, there was a dose-related increase in adverse events (e.g., headache, nausea, vasodilation, chest pain), consistent with the pharmacology of the drug. Binodenoson exhibited linear pharmacokinetics as indicated by a dose-proportional increase in peak concentration (C max ) and area under the concentration-time curve (AUC). Systemic clearance was independent of dose but was correlated with body weight. The mean terminal half-life of binodenoson across all doses was 10 +/- 4 minutes. CONCLUSIONS: Overall, binodenoson was well tolerated and exhibited linear pharmacokinetics when administered intravenously over a 60-fold dose range from 0.1 to 6 microg/kg.

Randomized, controlled dose-ranging study of the selective adenosine A2A receptor agonist binodenoson for pharmacological stress as an adjunct to myocardial perfusion imaging.

BACKGROUND: Dipyridamole and adenosine cause frequent side effects as a result of nonspecific adenosine receptor stimulation. Selective agonism of the adenosine A2A receptor should result in a similar degree of coronary vasodilation (and thus similar perfusion images) with fewer side effects. METHODS AND RESULTS: In a multicenter, randomized, single-blind, 2-arm crossover trial, 240 patients underwent 2 single photon emission computed tomographic (SPECT) imaging studies in random order, first after pharmacological stress with adenosine and a second study with the selective adenosine A2A receptor agonist binodenoson, using 1 of 4 dosing regimens. Safety, tolerability, and SPECT image concordance between the 2 agents were examined. Exact categorical agreement in the extent and severity of reversible perfusion defects ranged from 79% to 87%, with kappa values from 0.69 to 0.85, indicating very good to excellent agreement between binodenoson and adenosine. The risk of any safety event/side effect was significantly lower with any dose of binodenoson than with adenosine (P< or =0.01) because of a dose-related reduction in subjective side effects, as objective events were infrequent. There was a reduction in the severity of chest pain, dyspnea, and flushing in all binodenoson doses compared with adenosine (P<0.01), and the magnitude of severity reduction was dose-related. CONCLUSIONS: The selective adenosine A2A receptor agonist binodenoson results in an extent and severity of reversible perfusion defects on SPECT imaging similar to nonselective adenosine receptor stimulation, accompanied by a dose-related reduction in the incidence and severity of side effects.