 The purpose of this clinical study ChAMP - Comparability pharmacokinetics of Alpha-1 Modified Process is to compare the pharmacokinetic, safety and tolerability of Alpha-1 Proteinase Inhibitor Human, modified process Alpha-1 MP and Prolastin in adult Alpha1-antitrypsin deficient patients. Patients will be infused intravenously with study drug on a weekly schedule for 24 weeks. 