Phase 4, Double-blind Study Evaluating the Response on Computed Tomography (CT) Lung Density Decline Rates of Respreeza / Zemaira Weekly for 3 Years in Adults With alpha1 Antitrypsin Deficiency (AATD)

A Phase 4, Multicenter, Double-blind, Study to Investigate the Efficacy, Safety, and Tolerability of 3 Active Doses of Respreeza® / Zemaira® Weekly Intravenous Infusions Administered Over 3 Years as Longterm Maintenance Therapy in Adult Subjects With Emphysema Related to Alpha1 Antitrypsin Deficiency

This is a multicenter, parallel-group, double-blind, randomized phase 4 study designed to identify the optimal dose of CE1226 (2 active doses) to slow disease progression as assessed by reduced rates of annual lung density decline in alpha-1 antitrypsin (AAT) deficient participants over 3 years as compared with the marketed dose 60 milligrams per kilogram (mg/kg).

Inclusion Criteria:

• • Age greater than or equal to (>=) 18 and less than or equal to (<=) 65 years at the time of providing written informed consent.
• • Confirmed diagnosis of emphysema related to AATD with either the PiZZ, PiZ(null), or Pi(null/null) genotype with documented serum AAT levels less than (<) 11 micrometer (μM) (or < 50 mg/dL [milligram/deciliter]) at any time before the first administration of CE1226 on Day 1 (Baseline).

Exclusion Criteria:

• • Participants should not have acute illness or pulmonary exacerbation within 6 weeks before the first administration of CE1226 on Day 1 (Baseline).
• • Participants should not have previously received gene therapy for AATD at any point.
• • Participants with liver disease secondary to AATD.