---according to this Cochrane review. Med Page Today commentary here. The Cochrane reviewers were only able to find two studies that met their criteria: Randomised trials of augmentation therapy with alpha-1 antitrypsin compared with placebo or no treatment. Both looked at surrogate endpoints and neither addressed mortality. One surrogate endpoint (change in CT lung density) showed a statistically significant difference favoring treatment but the clinical significance is not known. There was no difference in exacerbations, quality of life of other endpoints.
I am not familiar with the primary literature on treatment of alpha-1 so this report raises more questions than answers for me. The medical press has hyped this somewhat but it's not as if it should be breaking news given that there were only two high level trials, both essentially negative, such that it wouldn't have taken a statistician to figure it out.
Professional societies endorse replacement therapies in their guidelines. Surely they were already aware of this literature. I have no idea whether this will change their recommendations for treatment. The important point is not that the treatment doesn't work (it seems to improve at least one surrogate endpoint and may ease the severity, although not the frequency, of exacerbations) but that we need a large RCT looking at mortality and other hard clinical endpoints, something like the National Emphysema Treatment Trial.
What about screening? Screening is widely advocated and has been widely believed to be underperformed. Although it will be interesting to see what the next round of guidelines say I will not change my approach that all patients with COPD or unremitting asthma should be screened. Screening is easy to do, is important for non-pulmonary disease associations and may still have treatment implications.