A randomized, double-blind, double-dummy, safety crossover trial comparing cumulative doses up to 96 microg of formoterol delivered via an HFA-134a-propelled pMDI vs. same cumulative doses of formoterol DPI and placebo in asthmatic patients.

BACKGROUND: Formoterol's effects on the cardiovascular system are well known, but whether these effects are altered by the reformulation of inhalers to replace CFC propellants with HFA propellants is not.

OBJECTIVES: To evaluate the effect of cumulative doses up to 96 microg of formoterol delivered via an HFA-134a-propelled pMDI, on cardiac safety and the QTc interval, compared the same cumulative doses delivered via a DPI, in adult patients with moderate-to-severe asthma.

METHODS: This study was a multicenter, double-blind, double-dummy, placebo-controlled, three-period, crossover trial in which 22 patients with moderate-to-severe asthma received cumulative doses up to 96 microg of formoterol (12 + 12 + 24 + 48 microg) delivered via a pMDI or a dry power inhaler (DPI). Vital signs and fourteen 12-lead ECG measurements were taken at each clinic visit and at 5-10 days after the final drug administration.

RESULTS: An increase from baseline in QTc interval was observed with all formoterol treatment arms in a dose-dependent manner. The maximum increases were 56.3, 62.6 and 25.0 ms for the formoterol pMDI, formoterol DPI and placebo treatments, respectively. Heart rate was increased by 10.7, 14.9 and 6.5 bpm in the pMDI, DPI and placebo groups, respectively. Both formoterol treatments were also associated with a decrease in diastolic blood pressure compared with placebo.

CONCLUSIONS: With respect to cardiovascular safety parameters, the administration of formoterol via a pMDI device is comparable to its delivery via a DPI.