THE ARISING · Longevity & Healthspan
Alpha-1 Liver Disease Gets a Shared Definition as RNA Editing Data Emerge
Liver disease caused by alpha-1 antitrypsin deficiency (AATD) is still going unrecognized in adults, and a new expert consensus aims to change that by agreeing on what it is, how to stage it and how to measure whether a treatment works.
The document is a consensus guidance, not a clinical trial. Published in Gastroenterology in 2026, it comes from a multidisciplinary international panel convened by the American Gastroenterological Association with the American Association for the Study of Liver Diseases, the European Association for the Study of the Liver and the Alpha-1 Foundation. The panel combined recent epidemiologic, tissue-based and noninvasive biomarker studies with expert opinion. The lead author is Rohit Loomba and the senior author is Pavel Strnad.
According to the guidance, AATD-associated liver disease remains underrecognized despite contributing to illness and death in adults with the PiZZ genotype, the form of the inherited condition most linked to liver harm. The authors say the lack of standard definitions, diagnostic criteria and staging has slowed both diagnosis and drug development.
The panel defines the disease by liver enzyme elevations, which may come and go, and/or liver fibrosis of stage F2 or higher in adults with AATD, particularly those with PiZZ. The enzymes named are aspartate aminotransferase, alanine aminotransferase and γ-glutamyl transferase. Fibrosis is scarring of the liver.
For staging, the panel preferred noninvasive elastography, which measures liver stiffness, over other methods. It named vibration-controlled transient elastography and magnetic resonance elastography as examples. A stiffness of 8 kPa or more on the first of these was set as the threshold for clinically significant fibrosis.
An investigational treatment is WVE-006, an investigational RNA editing drug given by injection under the skin. Wave reported interim open-label phase 1b/2a results from the RestorAATion-2 trial in May 2026, in adults with PiZZ AATD, with 8 participants in each dose group. The drug edits the messenger RNA in liver cells so that the body makes normal M-type AAT instead of the faulty Z type.
According to Wave’s May 18 announcement, single doses of 200, 400 and 600 mg produced M-AAT at 44%, 48% and 52% of total AAT, with Z-AAT falling by 47%, 50% and 59%. With repeated dosing, M-AAT reached 64% and 59% of total AAT in the 200 mg and 400 mg groups, and Z-AAT fell by 71% and 68%. In the available interim data, the company reported mild-to-moderate adverse events and no serious events.
The company had already reported these figures in May 2026. They are mean maximum biomarker responses, not demonstrated improvements in clinical liver or lung outcomes. The data are interim and come from small dose cohorts.
Next to watch: whether larger trials of RNA editing use the new liver definitions and stiffness thresholds as endpoints, and how the full RestorAATion-2 results compare with the interim figures.