Image: Tiotropium – CC/BenWeber. Trial info: Supported by Boehringer Ingelheim and Pfizer. ClinicalTrials.gov numbers, NCT00772538 and NCT00776984.
Primer: Exacerbations in asthmatics may persist despite treatment with inhaled glucocorticoids and long-acting beta-agonists (LABAs) – standard of care. Tiotropium is a long-acting anticholinergic bronchodilator approved for chronic obstructive pulmonary disease, but not asthma. The literature has suggested it provides benefit in asthmatics on top of standard care, however its effect on exacerbation frequency has never been assessed in a long-term clinical trial.
This [randomized] study: Just released today (Sept. 3) by the New England Journal of Medicine [NEJM], the results of two replicate (referred to as A and B) 48 week randomized trials assessing tiotropium + glucocorticoids/LABAs vs. placebo + glucocorticoids/LABAs were examined. 912 patients were split between the two replicate trials and then into respective treatment vs. placebo groups. The patient population selected were symptomatic, had forced expiratory volume in 1 second (FEV1) of <80% predicted and at least one severe exacerbation in the previous year. Primary outcomes measured included lung function and time to first severe exacerbation.
The change in FEV1 from baseline was greater with tiotropium group vs. the placebo population (p<.01 in trial A, p<.001 in trial B). The absolute effect was <10% improvement, but note that this is above the current standard treatment. The trough FEV1 was significantly improved in the tiotropium groups in both trials. Furthermore, tiotropium not only extended the time to first severe exacerbation by 56 days but also significantly reduced the risk of a severe exacerbation.
In sum: The number needed to treat in the 48-week period to prevent 1 exacerbation was 15. There were no differences in adverse events in either group. Though both trials (A and B) were true replicates, the authors could not explain the difference in the signifcance of results between the trials.
Click to read the report in the New England Journal of Medicine [NEJM]
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