Intravenous alpha-1 antitrypsin augmentation therapy for treating patients with alpha-1 antitrypsin deficiency and lung disease

BACKGROUND: Alpha-1 antitrypsin deficiency is an inherited disorder that can cause chronic obstructive pulmonary disease (COPD). People who smoke are more seriously affected and have a greater risk of dying from the disease. Therefore, the primary treatment is to help people give up smoking. There are now also preparations available that contain alpha-1 antitrypsin, but it is uncertain what their clinical effect is. OBJECTIVES: To review the benefits and harms of augmentation therapy with intravenous alpha-1 antitrypsin in patients with alpha-1 antitrypsin deficiency and lung disease. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed and ClinicalTrials.gov to 25 March 2016. SELECTION CRITERIA: We included randomised trials of augmentation therapy with alpha-1 antitrypsin compared with placebo or no treatment. DATA COLLECTION AND ANALYSIS: The two review authors independently selected trials, extracted outcome data and assessed the risk of bias. MAIN RESULTS: ) deteriorated more in participants in the treatment group than in the placebo group but the confidence interval (CI) included no difference (standardised mean difference -0.19, 95% CI -0.42 to 0.05; P = 0.12). For carbon monoxide diffusion, the difference was -0.11 mmol/minute/kPa (95% CI -0.35 to 0.12; P = 0.34). Lung density measured by computer tomography (CT) scan deteriorated significantly less in the treatment group than in the placebo group (mean difference (MD) 0.86 g/L, 95% CI 0.31 to 1.42; P = 0.002). Several secondary outcomes were unreported in the largest and most recent trial whose authors had numerous financial conflicts of interest. AUTHORS' CONCLUSIONS: This review update added one new study and 143 new participants, but the conclusions remain unchanged. Due to sparse data, we could not arrive at a conclusion about the impact of augmentation therapy on mortality, exacerbations, lung infections, hospital admission and quality of life, and there was uncertainty about possible harms. Therefore, it is our opinion that augmentation therapy with alpha-1 antitrypsin cannot be recommended.