The purpose of this clinical study is to assess the safety and tolerability of Alpha-1 MP in adult Alpha1-antitrypsin deficient patients.

The objective of this clinical trial (STAMP: Safety and Tolerability of Alpha-1 Modified Process) is to study the safety and tolerability of Alpha-1 MP in adult Alpha 1-antitrypsin deficient subjects as reported over 20 weeks of therapy. The primary objective is to describe the nature and frequency of treatment-emergent adverse events with "treatment-emergent" defined as any adverse event occurring after the start of the first study drug infusion.

Inclusion Criteria:

• Documented diagnosis of congenital Alpha1-antitrypsin deficiency
• Documented forced expiratory volume in 1 second (FEV1 ) between 20% - 80% of predicted value within last 6 months.
• Signed written informed consent prior to initiation of any study related procedures.

Exclusion Criteria:

• Females who are pregnant, breast feeding, or if of child-bearing potential, unwilling to practice adequate contraception throughout the study
• Use of systemic steroids within the 2 weeks prior to receiving study treatment (this does not include the use of inhaled steroids used on a routine or as needed basis).
• Subjects who have had exacerbations of their disease within one month of trial entry