Long-term effect of α1-antitrypsin augmentation therapy on the decline of FEV 1 in deficient patients: an analysis of the AIR database

Background: Patients with ZZ (Glu342Lys) α-1-antitrypsin deficiency (ZZ-AATD) who received augmentation therapy with α-1-antitrypsin (AAT) in randomised controlled trials over 2-3 years failed to show a significant reduction of the annual decline of forced expiratory volume in 1 s (FEV 1).

Methods: To compare the trajectory of FEV 1 change during 4 or more years in ZZ-AATD patients with emphysema receiving or not receiving intravenous augmentation therapy, a retrospective analysis of FEV 1 values entered in the Alpha-1 International Registry (AIR) of ZZ-AATD patients from five different European countries (Germany, UK, Spain, Italy and the Netherlands) was performed. The post-bronchodilator FEV 1 % predicted values for baseline and follow-up over time from patients were analysed using linear mixed effects models.

Results: Data of 374 patients were analysed: 246 untreated and 128 treated with intravenous AAT augmentation therapy. The mean±sd follow-up duration of the untreated group was 8.60±3.34 years and 8.59±2.62 years for the treated group. The mixed effects model analysis showed a mean FEV 1 decline of -0.931% predicted per year (95% CI -1.144 to -0.718) in the untreated group and a decline of -1.016% predicted per year (95% CI -1.319 to -0.7145) in the treated group. The likelihood ratio test showed no difference between the two groups (p=0.71).

Conclusion: In our study population, we could not detect a significant difference in the annual decline of FEV 1 by AAT augmentation treatment over a mean period of 8.6 years. Other approaches are needed to validate any benefit of augmentation therapy.