Durham – November 06, 2026 -- Brii Biosciences (2137.HK) reported that 41.9% of participants (62/148) in its Phase 2b ENRICH study achieved hepatitis B surface antigen (HBsAg) loss at end of treatment (EOT), with 32.4% (48/148) sustaining it 24 weeks later. The data were presented in three late-breaking sessions at the AASLD Liver Meeting in Denver, running November 5 to 9, 2026.
ENRICH reproduces the BRII-179 priming effect seen in ENSURE Cohort 4
ENRICH prospectively tested a strategy first identified in Cohort 4 of the ENSURE study, where BRII-179-experienced participants, particularly those developing anti-HBs responses, showed higher functional cure rates. Participants received BRII-179 every 3 or 2 weeks for 12 weeks before elebsiran and pegylated interferon alpha (PEG-IFNα). Results across both dose regimens matched the ENSURE observations.
Among participants with baseline HBsAg above 1,000 IU/mL and up to 3,000 IU/mL, 32.1% achieved HBsAg loss at EOT. At 24 weeks post-EOT, the rate was 20.8% (11/53). Most adverse events were consistent with the known profile of PEG-IFNα.
ENHANCE Part A1 triple therapy outperforms PEG-IFNα alone 25.5% to 10.2%
In virologically suppressed adults, concurrent BRII-179, elebsiran and PEG-IFNα delivered HBsAg loss in 25.5% (25/98) at EOT versus 10.2% (5/49) for PEG-IFNα monotherapy (p=0.0301). At 24 weeks post-EOT, the rates were 17.3% (17/98) versus 6.1% (3/49).
Immune responses followed the same pattern. At EOT, 50.0% of the triple-therapy group reached anti-HBs levels of at least 10 IU/L, and 40.8% reached at least 100 IU/L. Anti-HBs responses stayed limited in the monotherapy arm. Exploratory findings point to a potential association between higher anti-HBs levels at EOT and sustained HBsAg loss.
The gap widened in participants with baseline HBsAg above 1,000 IU/mL. Triple therapy produced HBsAg loss in 24.2% (8/33) at EOT and 18.2% (6/33) at 24 weeks post-EOT. No one in the monotherapy group (0/18) achieved it at either time point.
Part A2 halves PEG-IFNα duration to 24 weeks while holding HBsAg loss at 22.5%
Part A2 used a 24-week priming phase of BRII-179 and elebsiran, followed by elebsiran and a shortened 24-week PEG-IFNα course. That is a 50% cut from the 48 weeks of concurrent triple therapy in Part A1. HBsAg loss reached 22.5% (18/80) at EOT and 25.0% (20/80) at eight weeks post-EOT, comparable to Part A1's 25.5%.
At Week 24, 45.0% of participants had anti-HBs of at least 10 IU/L and 21.3% had at least 100 IU/L. Anti-HBs responders (at least 10 IU/L) recorded higher EOT HBsAg loss than nonresponders, 30.6% (11/36) versus 15.9% (7/44). At eight weeks post-EOT, the responder rate rose to 33.3% (12/36).
Baseline HBsAg shaped outcomes. Participants at or below 1,000 IU/mL reached 34.4% (11/32) at EOT and 37.5% (12/32) at eight weeks post-EOT. Those above 1,000 IU/mL reached 14.6% (7/48) and 16.7% (8/48) at the same points.
Higher-baseline patients, a historically difficult group, show measurable responses
Brii Bio said the ENRICH and ENHANCE results support further evaluation of BRII-179-based priming in participants with higher baseline HBsAg, where functional cure has historically been particularly challenging. Chief Medical Officer David Margolis said the findings give a "stronger scientific foundation" for continued evaluation and may guide future study design.
Across the studies, the regimens were generally safe and well tolerated. In ENHANCE Part A1, no new or unexpected safety signals emerged. In Part A2, Grade 3 or higher adverse events were rare during the priming period, and certain adverse events were reported less frequently than in Part A1, in the context of the shorter PEG-IFNα course.
ENRICH was presented orally by Jinlin Hou of Nanfang Hospital, Southern Medical University. Margolis presented ENHANCE Part A1 orally, and ENHANCE Part A2 was shown as a poster.