Title: Functional cure of chronic HBV infection

Background: Functional cure, defined as confirmed HBsAg loss after chronic HBV infection, is the surrogate gold standard goal for HBV management. This is thought to be a rare event: The HBV-Target consortium of 25 clinical sites have identified 111 with Functional Cure.

Purpose: Describe the population of those who have achieved functional cure in a single clinic in Toronto.

Method: SlicerDicer module of Epic was used to identify those who had achieved functional cure – labeled as ICD10 Z09.9. Of the 87 charts identified, 84 were confirmed to have functional cure.

Result(s): From June 6, 2022 to Jun 30, 2023, N=2,577 individual patients have been assessed. N=87 charts were identified by SlicerDicer, 84 individuals were confirmed to have Functional Cure on individual chart review. Most were males 60 (71%), mean age 65.5 years old, HBsAg loss documented at mean age 60 (range 30-80). Only 9 (10.7%) were born in Canada, most born in Asia 55 (65.5%) and Europe 13 (15.5%). Self identified race was predominantly East Asian 54 (64.3%) and White 20 (23.8%). 43 (51%) were treatment naïve. Of those who were treatment experienced, only 11 (13%) were still on treatment at the time of HBsAg loss. The remainder had been off treatment for 1-19 years. HCC diagnosed in 6 (7%) at age 71.5 years (range 56-82).

Conclusion(s): Functional cure is rare but does occur. Only 13% achieved HBsAg loss while on antiviral therapy whereas 41% achieved HBsAg loss after cessation of antiviral therapy.