The liver produces a protein called alpha-1 antitrypsin (AAT). AAT is normally released into the bloodstream. In some people, the liver makes an abnormal version of the AAT protein, called Z-AAT. Making an abnormal version of the AAT protein can result in liver disease as Z-AAT builds up in liver cells, which leads to liver problems such as liver scarring (fibrosis), continuing liver damage (cirrhosis), and eventually end stage liver disease. Fazirsiran is a medicine that reduces the creation of the Z-AAT protein and thus the build-up of this abnormal protein in the liver. People with this type of liver disease who already have mild liver scarring will take part in the study. They will be treated with fazirsiran or a placebo for about 2 years. This study will check the long-term safety of fazirsiran, whether participants tolerate the treatment and if there are any effects on liver scarring. A liver biopsy, a way of collecting a small tissue sample from the liver, will be taken twice during the study.
In the opinion of the investigator, the participant is capable of understanding and fully complying with the protocol requirements and adhering to the protocol schedule.
The participant is able to read, understand, and complete the study questionnaires electronically per the investigator's judgment.
The participant signs and dates a written Informed Consent Form (ICF). Any required privacy authorization should also be signed before the initiation of any study procedures.
The participant, of any sex, is aged 18 to 75 years, inclusive.
The participant has evidence of >= F2 fibrosis based on liver biopsy during the screening period.
The participant has a history of liver decompensating events.
The participant has a history of varices based on a previous esophagogastroduodenoscopy.
The participant has portal vein thrombosis.