Augmentation therapy for alpha-1 antitrypsin deficiency ‘ineffective’
MedWire News: Intravenous augmentation therapy for patients with alpha-1 antitrypsin (A1A) deficiency cannot be recommended as it has no proven clinical benefit, say researchers who conducted a systematic review of published studies.
A1A is a protease inhibitor that protects lung tissue against damage from inflammatory cells. People with A1A deficiency - an inherited condition - are at significantly increased risk for chronic obstructive pulmonary disease with emphysema, particularly those who are smokers.
The aim of A1A augmentation therapy is to boost levels of the protective protein in deficient patients, thus limiting damage to lung tissue and reducing mortality.
Peter Gøtzsche and Helle Krogh Johansen from the Nordic Cochrane Centre in Copenhagen, Denmark, searched the literature for randomized controlled trials of augmentation therapy with A1A.
Just two trials involving 140 patients with A1A deficiency met criteria for inclusion in the final analysis. In one trial, patients received intravenous A1A or placebo every 4 weeks for 3 years, and in the other patients received intravenous A1A or placebo weekly for a minimum of 2 years.
Mortality data, and the number of lung infections and hospital admissions were not reported in either study, the researchers report in the Cochrane Database of Systematic Reviews.
Overall, there were no significant differences between A1A- and placebo-treated patients in terms of quality of life (St George's Respiratory Questionnaire) or the annual number of exacerbations (2.6 vs 2.2).
Mean annual FEV1 and carbon monoxide diffusion deteriorated more in A1A- than placebo-treated patients, by 20 ml and 0.06 mmol/min/kPa, respectively.
However, lung density, as measured by computed tomography, decreased by 1.14 g/l more in placebo- than A1A-treated patients over the course of the studies.
Gøtzsche and Krogh conclude: "Augmentation therapy with alpha-1 antitrypsin cannot be recommended, in view of the lack of evidence of clinical benefit and the cost of treatment."
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By Mark Cowen