The Canadian Optimal Therapy of COPD Trial: design, organization and patient recruitment. In chronic obstructive pulmonary disease, a combination of ipratropium and albuterol is more effective than either agent alone. An 85-day multicenter trial. COMBIVENT Inhalation Aerosol Study Group.
There are no published studies that have assessed whether adding long-acting beta 2-agonist bronchodilators and/or inhaled steroids to chronic therapy with tiotropium would provide additional clinical benefit to patients with moderate to severe chronic obstructive pulmonary disease (COPD).
                The Canadian Optimal Therapy of COPD Trial is a randomized, prospective, double-blind, placebo-controlled, multicentre trial funded by the Canadian Institutes of Health Research that has been designed to determine which combination of inhaled medications will most effectively prevent exacerbations and optimize disease-specific quality of life in patients with COPD. The trial is the first to evolve from the Canadian Thoracic Society Clinical Trials Group. The study will randomize 432 patients with moderate to severe COPD to one of three parallel treatment arms for 52 weeks: tiotropium and fluticasone/salmeterol; tiotropium and salmeterol; or tiotropium and placebo inhaler. The participants will be allowed to use salbutamol as required throughout the trial period.
                The primary outcome measure is the proportion of patients in the three treatment groups who experienced a respiratory exacerbation within 52 weeks of randomization. Other outcomes that will be assessed over the 52-week trial period will include: changes in disease-specific quality of life and changes in dyspnea, health care use and changes in lung function. A pharmacoeconomic analysis will also be performed to evaluate the cost of these therapies.
                The study commenced recruitment in October 2003. It is currently operating at 22 centres across Canada and has randomized 137 patients during the first four months of recruitment. Recruitment is scheduled to continue until April 2005 or until 432 patients have been randomized.
                The present randomized, placebo-controlled trial offers a unique opportunity to answer the question, what is the best combination of inhaled medications to use for COPD patients? It is hoped that optimal use of inhaled medications will improve patient health and quality of life, reduce patient respiratory exacerbations, and ultimately, reduce health care resource use. Combination bronchodilator therapy for chronic obstructive pulmonary disease (COPD) is available widely throughout the world except in North America. Previous studies have yielded conflicting results regarding the advantages of combining anticholinergic therapy with sympathomimetic therapy in COPD. We report the results of a 12-week prospective, double-blind, parallel-group evaluation of the use of the following: albuterol, a beta-adrenergic agent; ipratropium, an anticholinergic agent; or a combination of the two, administered by metered-dose inhaler to patients with moderately severe stable COPD. Following baseline studies, 534 patients were given one of the three test bronchodilator preparations to be used at home four times daily in addition to oral theophylline and corticosteroids as required. The doses of the latter two drugs were kept stable. Subjects were tested on days 1, 29, 57, and 85. Analysis of 1-s forced expiratory volume (FEV1) curves on those test days indicated that the combination was superior to either single agent alone in peak effect, in the effect during the first 4 h after dosing, and in the total area under the curve of the FEV1 response. The mean peak percent increases in FEV1 over baseline on the four test days were 31 to 33 percent for the combination, 24 to 25 percent for ipratropium, and 24 to 27 percent for albuterol. The differences between the combination and its components were statistically significant on all test days. The AUC0-4 means for the combination were 21 to 44 percent greater than the ipratropium means and 30 to 46 percent greater than the albuterol means. Similar changes were noted in the forced vital capacity curves. Symptom scores did not change over time and did not differ among the treatment groups. We conclude that the combination of ipratropium and albuterol, when given by metered-dose inhaler to patients with COPD, is more effective than either of the two agents alone. The advantage of the combination is apparent primarily during the first 4 h after administration. The availability of combination therapy by metered-dose inhaler should help to improve patient compliance.
Since the proportion of missing outcome data compared to the observed outcome data is enough to induce a clinically relevant bias in the intervention effect, the relative efficacy and safety of combined inhalers and tiotropium remains uncertain. Further large, long-term randomised controlled trials comparing combination therapy to tiotropium are required, including adequate follow-up of all participants randomised (similar to the procedures undertaken in TORCH and UPLIFT). Additional studies comparing alternative inhaled long-acting beta2-agonist/steroid combination therapies with tiotropium are also required.