An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of the study intervention, whether or not it is considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of the study intervention. An SAE is defined as any untoward medical occurrence that results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, congenital anomaly/birth defect, suspected transmission of any infectious agent, an important medical event. AEs and SAEs including any pulmonary AEs or SAEs indicative of worsening pulmonary condition (example, pulmonary exacerbation, respiratory infection, significant pulmonary function test decline) will be reported.

Standard pulmonary function parameters will be used to study lung function. Clinical significance of pulmonary function parameters will be determined at the investigator's discretion.

Change from baseline in whole lung 15th percentile density as measured by CT lung densitometry will be assessed.

Vital signs include body temperature, respiratory rate, blood pressure (systolic and diastolic), pulse (beats per minute) and pulse oximetry. Clinical significance of vital signs will be determined at the investigator's discretion.

12-lead ECG will be evaluated. Any clinically significant change in ECG assessments will be determined at the investigator's discretion.

Laboratory parameters assessments include hematology, biochemistry including liver tests, coagulation, and urinalysis. Clinical significance of laboratory parameters will be determined at the investigator's discretion.

Standard pulmonary function parameters measured will be used to study lung function. Clinical significance of pulmonary function parameters will be determined at the investigator's discretion.

Laboratory parameters include hematology, biochemistry including liver tests, coagulation, and urinalysis. Clinical significance of laboratory parameters will be determined at the investigator's discretion.

Reduction from baseline of at least 1 stage of histologic fibrosis METAVIR staging in the centrally read liver biopsy at Week 106 in AATD-LD with METAVIR stage F2 and F3 fibrosis will be assessed.