A randomized, double-blind, placebo-controlled study assessing the safety and tolerability of regadenoson in subjects with asthma or chronic obstructive pulmonary disease.

BACKGROUND: Adenosine receptor stress agents for myocardial perfusion imaging (MPI) may cause A(2B) and/or A(3) receptor-mediated bronchoconstriction, of particular concern to physicians testing patients with asthma or chronic obstructive pulmonary disease (COPD). METHODS: A Phase 4, randomized, double-blind study (NCT00862641) assessed the safety of the selective A(2A) receptor agonist, regadenoson, compared with placebo in subjects with asthma or COPD who represented likely candidates for MPI. RESULTS: Overall, 356 and 176 subjects with asthma and 316 and 151 subjects with COPD received regadenoson and placebo, respectively. The percentage of subjects experiencing a >15% decrease in FEV(1) from baseline to any assessment up to 24 hours post-baseline was not statistically significantly different between the regadenoson and the placebo groups in the asthma or COPD stratum. Dyspnea, the most frequent respiratory adverse event, occurred with higher incidence (P < .0001) in the regadenoson group than the placebo group in the asthma (10.7% vs 1.1%) and COPD (18.0% vs 2.6%) strata. No subjects experienced severe bronchoconstriction, although the occurrence of such reactions with adenosine receptor agonists cannot be ruled out, such that caution is advised. CONCLUSIONS: This information may be helpful to physicians selecting a pharmacologic stress agent for MPI in patients with asthma or COPD.

Efficacy and safety of 30-minute infusions of conivaptan in euvolemic and hypervolemic hyponatremia.

PURPOSE: The efficacy and safety of conivaptan administered via 30-minute i.v. infusion to patients with euvolemic or hypervolemic hyponatremia were evaluated. METHODS: Hospitalized adults with a baseline serum sodium concentration (SSC) of 115-130 meq/L and euvolemia or hypervolemia on clinical evaluation were randomized to receive conivaptan hydrochloride 20 mg once or twice daily or placebo via 30-minute i.v. infusion. The primary efficacy measure was the change in SSC from baseline to 48 hours. RESULTS: A total of 49 patients received one of the three treatment regimens. Conivaptan once and twice daily produced significant least-squares mean changes from baseline in SSC at 48 hours of 3.46 meq/L (95% confidence interval [CI], 1.75-5.18 meq/L) and 6.22 meq/L (95% CI, 4.34-8.10 meq/L), respectively (p = 0.028 between conivaptan-treated groups). These changes were significantly greater compared with those in the placebo group at hour 4 (p = 0.049) and at all time points onward of hour 28 (p ≤ 0.019) for the once-daily regimen and at all time points for the twice-daily regimen (p = 0.045 at hour 4, then p ≤ 0.010). Both conivaptan regimens were more efficacious than placebo in all secondary efficacy outcomes. Conivaptan was generally well tolerated, with infusion-site reactions being the most common adverse effects (AEs). CONCLUSION: Conivaptan hydrochloride 20 mg, administered once or twice daily via 30-minute i.v. infusion, significantly increased SSCs over 48 hours in patients with euvolemic or hypervolemic hyponatremia when compared with placebo. Common AEs were similar to those seen with continuous conivaptan infusions.

Effect of loading dose and formulation on safety and efficacy of conivaptan in treatment of euvolemic and hypervolemic hyponatremia.

PURPOSE: The effect of loading dose and formulation on the safety and efficacy of conivaptan in the treatment of euvolemic and hypervolemic hyponatremia was studied. METHODS: This parallel-group study randomized 121 hospitalized patients with euvolemic or hypervolemic hyponatremia to one of four treatment regimens: placebo loading dose followed by conivaptan continuous i.v. infusion using the ampul formulation (regimen 1), conivaptan loading dose followed by continuous i.v. infusion using the ampul formulation (regimen 2), placebo loading dose followed by conivaptan continuous i.v. infusion using the premixed formulation (regimen 3), or conivaptan loading dose followed by continuous i.v. infusion using the premixed formulation (regimen 4). The primary variable was the incidence and severity of injection-site reactions (ISRs), as evaluated using the ISR modified 5-point scale (ISRMS). Secondary outcomes included effects on serum sodium concentration (SSC), duration of effect, and safety and tolerability. RESULTS: All four dosing regimens were efficacious, safe, and well tolerated. No significant differences in ISRMS scores or differences in changes from baseline SSC or in the duration of effects on SSC were observed between the regimens. Overly rapid SSC increases occurred in 7%, 7%, 3%, and 21% of patients treated with regimens 1, 2, 3, and 4, respectively. Overall, adverse events related to general disorders and ISRs occurred in 39%, 43%, 53%, and 55% of patients receiving regimens 1, 2, 3, and 4, respectively. CONCLUSION: Intravenous conivaptan regimens with or without a loading dose, whether using the ampul or a premixed formulation, had similar safety, tolerability, and efficacy in patients with euvolemic or hypervolemic hyponatremia. The pre-mixed formulation used with a loading dose may be associated with an increased frequency of overly rapid increase in SSC compared with the other regimens studied.

Effect of caffeine on SPECT myocardial perfusion imaging during regadenoson pharmacologic stress: rationale and design of a prospective, randomized, multicenter study.

BACKGROUND: Caffeine attenuates the coronary hyperemic response to adenosine by competitive A2(A) receptor blockade. This study aims to determine whether oral caffeine administration compromises diagnostic accuracy in patients undergoing vasodilator stress myocardial perfusion imaging (MPI) with regadenoson, a selective adenosine A(2A) agonist. METHODS: This multicenter, randomized, double-blind, placebo-controlled, parallel-group study includes patients with suspected coronary artery disease who regularly consume caffeine. Each participant undergoes three SPECT MPI studies: a rest study on day 1 (MPI-1); a regadenoson stress study on day 3 (MPI-2), and a regadenoson stress study on day 5 with double-blind administration of oral caffeine 200 or 400 mg or placebo capsules (MPI-3; n = 90 per arm). Only participants with ≥ 1 reversible defect on the second MPI study undergo the subsequent stress MPI test. The primary endpoint is the difference in the number of reversible defects on the two stress tests using a 17-segment model. Pharmacokinetic/pharmacodynamic analyses will evaluate the effect of caffeine on the regadenoson exposure-response relationship. Safety will also be assessed. CONCLUSION: The results of this study will show whether the consumption of caffeine equivalent to 2-4 cups of coffee prior to an MPI study with regadenoson affects the diagnostic validity of stress testing (ClinicalTrials.gov number, NCT00826280).