A clinical trial gave patients with severe hepatitis B‑related liver failure a daily injection of thymosin‑alpha‑1 for a week, then twice a week for three months. The treated group lived longer without needing a liver transplant and got fewer infections and brain‑related complications than those who only got standard care. The peptide was well‑tolerated, but the study focused on very sick liver patients, not healthy people.

Mortality from hepatitis B virus (HBV)-related acute-on-chronic liver failure (ACLF) is high. Severe infection is the most important complication that affects the outcomes of ACLF patients. Thymosin α1 (Tα1) can improve immune imbalance and this study aimed to investigate the safety and efficacy of Tα1 treatment for HBV-related ACLF. From 2017 to 2019, 120 patients with HBV-related ACLF were enrolled in this open-label, randomized, and controlled clinical trial (ClinicalTrial ID: NCT03082885). The control group (N = 58) was treated with standard medical therapy (SMT) only. The experimental group (N = 56) was subcutaneously injected with 1.6 mg of Tα1 once a day for the first week and then twice a week from week 2 to week 12. The 90-day cumulated liver transplantation free survival rate of the Tα1 group was 75.0% (95% confidence interval 63.2-86.8%) versus 53.4% (95% confidence interval 39.7-67.1%) for the SMT group (p = 0.030). No significant difference was found in the survival using competitive risk analysis. The incidences of new infection and hepatic encephalopathy in the Tα1 group were much lower than those in the SMT group (32.1% vs 58.6%, p = 0.005; 8.9% vs 24.1%, p = 0.029, respectively). Mortality from severe infection in the SMT group was higher than in the Tα1 group (24.1% vs 8.9%, p = 0.029). Tα1 is safe for patients with HBV-related ACLF and significantly improves the 90-day liver transplantation-free survival rate. There may be a subgroup which may benefit from Tα1 therapy by the mechanism of preventing infection.