GSK reveals positive but lackluster data from the Ph2b B-Together study (bepirovirsen + pegIFN) in AASLD 2023 abstract

AASLD 2023 abstracts were released on October 10^th, 2023.

GSK presents an oral abstract that will highlight results from the Ph2b B-Together study (bepirovirsen + pegIFN, N=108).  

Key Highlights of the Oral Abstract

• The Ph2b B-Together study (N=108) was an open label study where patients received 300mg of bepirovirsen (bepi) (SC Q1W) for 12 wks or 24 wks and then received pegIFN for 24 wks
• Serious adverse events were experienced by 8 pts (7%), however no new safety signals were observed for bepi
• Efficacy results were:

CI Assessment

• This is the first look of bepi activity in combination with another component required for potential functional cure of 30%
  • Data from this study demonstrates lackluster functional cure rates and limited additive benefit of pegIFN when compared to results from B-CLEAR bepi monotherapy study, which demonstrated ~9% functional cure rate
  • Recall, VIR-2218 + peg-IFN demonstrated a SVR24 was 16.1% (5/31)
• This data supports the notion that ASOs in combination therapies can achieve a durable response in HBV but addition of a third component is likely needed
  • GSK is currently conducting a Ph2b study evaluating bepi in combination with a vaccine (N=184); data from this study is expected to readout in H1 2026
  • GSK is the only competitor in HBVCure who has all three components to potentially achieve functional cure, however, GSK is yet to initiate a clinical trial with three components
• If GSK continues to develop the bepi + pegIFN combination, an approval as early as 2028 would be possible following the successful completion of a Ph3 study
  • If bepi monotherapy is approved (~2026), bepi could be combined with Peg-IFN off-label before approval of the combo

In addition to this abstract, GSK will also present 8 other abstracts for HBV including 2 post-hoc analyses from Ph2b B-Together study. The post-hoc analyses explore the responses of different HBV genotypes to bepi + pegIFN and mechanistic PK/PD modelling and simulation to inform Ph3 study design. More details on the HBV abstracts from GSK can be found in the table below.

HBV portfolio

Other GSK HBV studies: