Patient ethnicity, HBV genotype predict functional cure after therapy withdrawal

The chances of hepatitis B surface antigen (HBsAg) loss after withdrawing nucleo(s)tide analogue (NUC) treatment depend on factors such as patient ethnicity, end-of-treatment antigen levels, and HBV genotype, a new study reports.

The study included 1,216 patients (median age 50 years, 72.4 percent men) with undetectable HBV DNA levels who discontinued long-term NUC treatment. The primary outcome was HBsAg loss at any time during off-treatment follow-up. Non-response was defined as needing retreatment after cessation.

Almost half (44.5 percent; n=541) of patients reinitiated therapy a median of 34 weeks after initial withdrawal. Only 98 patients (8.1 percent) were able to clear HBsAg after a median follow-up of 102.5 weeks. None of the patients restarting therapy cleared HBsAg.

The resulting overall cumulative probabilities of HBsAg loss were 1.4 percent, 4.1 percent, and 5.9 percent at 48 weeks, 96 weeks, and 144 weeks after therapy cessation, respectively.

Ethnicity emerged as an important factor influencing HBsAg loss probability, with non-Asians being more than eight times more likely to achieve HbsAg loss than Asian counterparts (adjusted hazard ratio [aHR], 8.289; p<0.001).

Moreover, lower levels of HBsAg (aHR, 0.243; p<0.001) and hepatitis B core-related antigen (aHR, 0.718; p=0.001) at the end of treatment were significantly associated with a better likelihood of HBsAg loss.

Finally, viral genotype also significantly affected HBsAg loss. Asian patients with HBV genotype C were significantly more likely to reach such an outcome compared to counterparts with HBV genotype B (aHR, 2.494; p=0.001).