BACKGROUND:
Severe congenital deficiency for alpha1-antitrypsin is associated with the early onset of emphysema, usually by the third decade of life. One approach to correct this deficiency is though replacement with alpha1-antitrypsin (referred to as alpha1-proteinase (A1Pi) inhibitor in its purified form). An intravenous preparation of A1Pi concentrate was produced from human plasma by Cutter Biological, a division of Miles, Inc., Berkeley, California. This preparation had been evaluated in a clinical study for its safety and biochemical efficacy. Based on the augmentation of its levels in the lung upon intravenous administration, the A1Pi preparation was licensed by the Food and Drug Administration for replacement therapy to treat individuals with severe congenital deficiency and impaired lung function. When the registry began in 1988, clinical efficacy was plausible, but unproven and there was no data base for estimating the degree of clinical benefit, if any.
Slow progression of emphysema and lack of an adequate control group have made it difficult to evaluate the proteinase inhibitor through a controlled clinical trial. A patient registry was an alternative method to collect data on the effect of long-term replacement therapy with A1Pi on rate of decline of lung function. The registry also included individuals who did not receive the replacement therapy in order to obtain a better knowledge of the rate of decline of lung function associated with the congenital deficiency for alpha1-antitrypsin.
DESIGN NARRATIVE:
The registry consisted of a clinical coordinating center, 37 participating clinical centers that contributed patient data to the registry, a steering committee, and a data analysis and policy board, both appointed by the National Heart, Lung, and Blood Institute. Data collected on all patients included a clinical history, laboratory evaluations such as chest x-ray, lung function studies of vital capacity, total lung capacity, forced expiratory volume in one second (FEV1) and blood studies. In addition, patients receiving replacement therapy had baseline lung function tests, spirometry every six months following initiation of replacement therapy, and measurements of serum alpha1-antitrypsin level pre- and post-infusion, once every six months. The recruitment phase ended in September 1990. Support for the registry ended in June, 1998.
