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Off-therapy response after nucleos(t)ide analogue withdrawal in patients with chronic hepatitis B: An international, multi-center, multi-ethnic cohort (RETRACT-B study).

BACKGROUND AND AIMS
Functional cure, defined by hepatitis B surface antigen (HBsAg) loss, is rare during nucleos(t)ide analogue (NA) therapy and guidelines on finite NA therapy have not been well established. We aim to analyze off-therapy outcomes following NA cessation in a large, international, multi-center, multi-ethnic cohort of chronic hepatitis B (CHB) patients.


METHODS
This cohort study included virally suppressed CHB patients who were hepatitis B e antigen (HBeAg) negative and stopped NA therapy. Primary outcome was HBsAg loss after NA cessation, and secondary outcomes included virological, biochemical, and clinical relapse, ALT flare, retreatment, and liver-related events after NA cessation.


RESULTS
Among 1,552 CHB patients, cumulative probability of HBsAg loss was 3.2% at 12 months and 13.0% at 48 months of follow-up. HBsAg loss was higher among Caucasians (vs. Asians: SHR 6.8; 95% CI 2.7-16.8; P < .001), and among patients with HBsAg levels <100 IU/mL at end of therapy (vs. ≥100 IU/mL: SHR 22.5; 95% CI 13.1-38.7; P < .001). At 48 months of follow-up, Caucasians with HBsAg levels <1000 IU/mL and Asians with HBsAg levels <100 IU/mL at end of therapy had a high predicted probability of HBsAg loss (>30%). Incidence rate of hepatic decompensation and hepatocellular carcinoma (HCC) was 0.48 per 1000 person-years and 0.29 per 1000 person-years, respectively. Death occurred in 7/19 decompensated patients and 2/14 patients with HCC.


CONCLUSION
The best candidates for NA withdrawal are virally suppressed, HBeAg negative, non-cirrhotic CHB patients with low HBsAg levels, particularly Caucasians with <1000 IU/mL and Asians with <100 IU/mL. However, strict surveillance is recommended to prevent deterioration.