The Pharmaceutical Journal
Vol 268 No 7199 p705-712
25 May 2002

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Inhaled steroids switch can destabilise asthma

Switching patients with stable persistent asthma from their inhaled corticosteroid to a long acting beta₂ agonist may not reduce their peak flow but it could destabilise their asthma and increase their risk of exacerbations, Professor Paul O'Byrne from McMaster University, Ontario, Canada, warned delegates at the American Thoracic Society meeting in Atlanta, this week.

In a review of what he considered to be the most important asthma papers published last year, Professor O'Byrne described the results of a 28-week placebo controlled trial of over 150 patients with stable persistent asthma, a third of whom were switched to salmeterol 42 micrograms twice daily and a third of whom remained on their inhaled steroid — triamcinolone 400 micrograms twice daily (JAMA 2001:285:2583). The remaining third were switched to placebo. During the study, there were no significant differences in peak flow or symptom scores between the two groups on active treatment. But there were more treatment failures in the salmeterol than the triamcinolone group (24 per cent vs 6 per cent, P=0.004) and more asthma exacerbations (20 per cent vs 7 per cent, P=0.04).

Another noteworthy trial was a study of bone density in 109 premenopausal women taking triamcinolone for their asthma (New England Journal of Medicine 2001;345:941). Those taking the largest amounts of inhaled corticosteroid (>8 puffs/day) had a reduction in hip and trochanter bone density over three years, compared to those using smaller doses. But Professor O'Byrne described the bone density data as a "scattergram" of values since there was such a large variation in results. More important, he felt, was the lack of correlation in the study between bone density data and the biochemical markers of bone turnover which are frequently used in clinical trials of inhaled corticosteroids as surrogate endpoints for effects on bone density and growth.

Professor O'Byrne praises a 28-week placebo controlled study of the anti-IgE antibody, omalizumab, administered every two or four weeks to 525 people with moderate to severe allergic asthma (Journal of Allergy and Clinical Immunology 2001;108:184). He described the "surprising degree of efficacy" of the treatment in such severely ill patients, nearly 40 per cent of whom were able to discontinue their inhaled corticosteroid.
— Contributed.