Efficacy of a new intravenous β₂-adrenergic agonist (bedoradrine, MN-221) for patients with an acute exacerbation of asthma

Background Many patients with acute exacerbation of asthma are non-responders to inhaled β-adrenergic agonists. The goal of this study was to evaluate the safety and efficacy of intravenous bedoradrine (MN-221), a highly selective β₂-adrenergic agonist, as adjunct to standard therapy in the management of patients with acute exacerbation of asthma who did not respond to standard therapy. Methods Patients (N = 167) received standard therapy and were randomized to either bedoradrine (1200 μg) or placebo. Safety and efficacy parameters were monitored hourly for 3 h, followed by a 24-h follow-up visit and an 8-day follow-up phone call. Change in %FEV₁ from baseline to Hour 3 was the primary outcome. Secondary outcome measures included change in %FEV₁ at 1 and 2 h, change in dyspnea score at 1, 2, and 3 h, treatment failure rate, defined as a combination of hospitalization on the index visit or return to the emergency department within 1 week, and safety monitoring. Results There was no significant difference in %FEV₁ at 3 h between the 2 groups. The dyspnea scores were significantly improved for patients treated with bedoradrine compared to placebo (AUC_{0-2 h} P < 0.005, AUC_{0-3 h} P < 0.05). The safety profile for those treated with bedoradrine was consistent with the known mechanism of action of β-adrenergic agonists, and included both cardiovascular and metabolic effects. Conclusions Intravenous bedoradrine, in addition to standard therapy, did not significantly increase %FEV₁ at 3 h, but it was associated with significantly improved dyspnea scores.