A Six-week Study Comparing the Efficacy and Safety of Tiotropium Plus Formoterol to Salmeterol Plus Fluticasone in Chronic Obstructive Pulmonary Disease (COPD)

Tiotropium (Spiriva®) is a once-daily inhaled anticholinergic for the treatment of COPD. A six-week, multicentre, randomized, double-blind, parallel group study was conducted to compare the efficacy and safety of the free combination of tiotropium 18 µg once daily plus formoterol 12 µg b.i.d. [Tio+For] to salmeterol 50 µg b.i.d. plus fluticasone 500 µg b.i.d. [Sal+Flu] in COPD patients. Information regarding the differential efficacy and safety of the two different combinations may be essential for physicians to make informed choices of therapy for COPD patients considered candidates for combination therapy.

Following an initial screening visit, subjects entered a two or four-week run-in period in which they received ipratropium (Atrovent®) on a regular basis. At the second visit (Baseline), subjects were randomized into the six-week, double blind portion of the study in which they received either Tio+For or Sal+Flu. After three weeks of treatment, an interim visit was scheduled. After six weeks of treatment, a 12-hour profile of pulmonary function testings (FEV1, FVC) was obtained. Spirometric measurements were performed at pre-dose and 30 minutes, 1, 2, 3, 4, 6, 8, 10 and 12 hours post-dosing. There were two co-primary endpoints: FEV1 area under the curve for the time period 0 to 12 hours (FEV1 AUC0-12) and peak FEV1.

The efficacy evaluation (intention-to-treat) comprised 592 patients [Tio+For: N=297, Sal+Flu: N=295]. The two treatment groups were comparable with regard to demographic data and baseline disease characteristics [Baseline FEV1 (±SE): Tio+For: 1.310 L (±0.026 L); Sal+Flu: 1.325 L (±0.025 L)]. Adjustment was done for baseline and centre-effects.

Study Hypothesis:

The following primary hypotheses (one-sided) were tested with regard to superiority (all means are adjusted means):

H01: FEV1AUC(0-12 hours) (tiotropium+formoterol) <= FEV1AUC (0-12 hours) (salmeterol+fluticasone) versus H11: FEV1AUC(0-12 hours) (tiotropium+formoterol) > FEV1AUC 0-12 hours(salmeterol+fluticasone)

It was stipulated in the protocol that, if the null hypothesis H01 was rejected in favour of H11, then the following hypothesis would be tested:

H01: Peak FEV1 (tiotropium+formoterol) <= Peak FEV1 (salmeterol+fluticasone) versus H11: Peak FEV1 (tiotropium+formoterol) > Peak FEV1 (salmeterol+fluticasone)

Each step was only considered confirmatory providing all previous steps were successful. If any of the previous steps were not successful, any analysis of the current step would have been considered descriptive.

Comparison(s):

Test therapy:

Test product: Tiotropium inhalation capsules plus formoterol inhalation capsules Dose: 18 µg tiotropium per day (one capsule), 12 µg formoterol twice daily (two times one capsule) Mode of administration: inhalation via the Handihaler device (tiotropium), inhalation via the Blue Inhaler device (formoterol)

Reference therapy:

Test product: Salmeterol plus fluticasone propionate Dose: Salmeterol 50 µg (2 puffs of 25 µg each) b.i.d., fluticasone propionate 500 µg (2 puffs of 250 µg each) b.i.d.

Mode of administration: inhalation via MDI

The treatment duration was 42 days each. Primary endpoint measurements were performed on the last treatment day.