Liver specialists from around the world have agreed on a unified definition for acute-on-chronic liver failure, a condition that has long lacked a consistent standard across regions despite being common and potentially fatal.
The agreement is more than a terminology cleanup. By aligning how ACLF is diagnosed, the group is also trying to remove a major obstacle to treatment development: if different parts of the world use different definitions, trial populations, endpoints, and care pathways are harder to compare.
The Definition
According to the position paper published in Hepatology last month, a patient must have a bilirubin level of at least 1.5 and an international normalized ratio, or INR, of at least 5 to be diagnosed with ACLF. If those thresholds are met, providers can then assess dysfunction in the brain, kidneys, circulatory system, or respiratory system.
The effort brought together experts from five liver societies, along with pharmaceutical companies and regulators, at a meeting in Barcelona this May. Jasmohan Bajaj, a hepatologist and professor of internal medicine at Virginia Commonwealth University’s School of Medicine, told STAT that confusion around the condition had made it difficult for clinicians to know how to use the concept in practice.
The source described ACLF as an acute injury worsening underlying liver disease. In the U.S., that often means long-simmering cirrhosis that is suddenly exacerbated by alcohol or a viral infection. One reason a formal definition mattered is that ACLF can be confused with acute liver failure, which develops rapidly without an underlying liver illness.
Why It Matters For Policy And Development
The line between those two conditions has practical consequences. Bajaj said that, at least in the U.S. and some Western countries, patients with acute liver failure receive extra points that can move them to the top of the liver transplant list, while patients with ACLF do not currently receive the same treatment.
The paper also includes guidance on drug-induced liver injury, transplant, and clinical trial endpoints for pharmaceutical companies developing therapies. Bajaj said the participants received unofficial feedback from the FDA on clinical trial endpoints, including warnings that some approaches would not support a registrational intervention.
That gives the definition policy weight beyond academic consensus. A standard tied to how regulators think about endpoints can shape which studies are run, how sponsors choose inclusion criteria, and whether data generated in one region can be used more broadly.
What Was Settled, And What Was Not
Bajaj said the group benchmarked the framework to 30-day mortality across multiple consortia rather than relying only on expert preference for particular cutoffs. He also said some issues were left unresolved for future work, including whether to subdivide patients with no decompensation cirrhosis versus decompensated cirrhosis, as well as questions around immune dysfunction and gut failure.
Even with those open points, the immediate signal is that liver medicine now has a common thread for diagnosing ACLF and studying it. For companies and investigators, that does not create a therapy by itself, but it does create a clearer basis for building one.
