Press Release

MONTREAL, July 29th, 2019 – Replicor Inc., a privately held biopharmaceutical company targeting a cure for patients with chronic hepatitis B virus (HBV) and chronic HBV and hepatitis delta virus (HDV) co-infection, today announced the publication of new data examining the evolution of HBsAg immunoreactivity during REP 2139 therapy in the Journal of Viral Hepatitis (

This article, entitled “Kinetics of hepatitis B surface antigen quasispecies during REP 2139‐Ca therapy in HBeAg positive chronic HBV infection” is a follow-up study of the analysis of HBsAg during REP 2139 therapy in the REP 102 study ( and provides a deep sequencing analysis of the major immunoreactive domain (the a-determinant) of HBsAg and adjacent regions within the major hydrophilic region. This new study was from Replicor’s collaboration with Dr. Michael Roggendorf at the Technical University of Munich (TUM), Germany.

From this deep sequencing analysis, no HBsAg quasispecies with mutations that would evade detection were observed throughout REP 2139 exposure. Moreover, the kinetics of changes in quasispecies diversity suggested HBsAg declines may be linked to immune clearance and the ability of the host immune system to efficiently target all existing quasispecies. These data continue to confirm the validity of HBsAg responses observed in all clinical studies with NAPs and are consistent with the improved HBsAg clearance observed with the addition of immunotherapy to REP 2139.

Dr. Vaillant, CSO at Replicor commented, “This study reminds us of the plasticity of HBV infection, which can rapidly endanger numerous quasispecies that can persist chronically in cccDNA and perhaps even dictate the composition of integrated HBV DNA overtime. Since REP 2139 can only prevent replenishment of HBsAg, the clearance of HBsAg from the blood during REP 2139 therapy is likely governed at least in part by the ability of the immune response to react against the multitude of HBsAg quasispecies present. This study adds to the data we have previously generated suggesting immune function is important to overall virologic response during REP 2139 therapy and will be used to help guide future immunological analyses during REP 2139-Mg based therapy.”

About Replicor

Replicor is a privately held biopharmaceutical company with the most advanced animal and human clinical data in the development of the cure for HBV and HDV. The company is dedicated to accelerating the development of an effective treatment for patients with HBV and HBV/HDV co-infection. For further information about Replicor please visit our website at

Media Contact:
Natacha Dorget
(514) 733-1998