Mitchel L. Zoler/MDedge News
Dr. Fabien Zoulim
Several novel drug classes aimed at new viral targets, such as capsid inhibitors, are in various stages of clinical development, said Fabien Zoulim, MD, head of the gastroenterology and hepatology service at the Red Cross Hospital in Lyon, France, and another member of the writing panel. “We have many drug candidates” that use novel approaches to further restrict viral growth, roughly 50 agents in phase 1 and 2 studies, he said during the press briefing, held during the meeting sponsored by the European Association for the Study of the Liver. The other, immunologic aspect of the two-part cure strategy – restoring the “exhausted” HBV-specific T-cell population and stimulating production of neutralizing antibody to HBV – remains hypothetical right now, however. “It’s a concept that needs development,” Dr. Zoulim said.
A reason members of the coalition are optimistic about eventual prospects for a cure is that currently about 1% of patients on HBV antiviral treatments have a functional cure after relatively brief treatment, and the percentage of cured patients plateaus at about 10% among those who remain on current HBV antiviral drugs for several years. In addition, a substantial fraction of patients spontaneously resolve their HBV infection without any treatment. Experts estimate that more than 1 billion people worldwide have been infected by HBV and then later had their infection clear “naturally,” said Dr. Revill. But the mechanism by which this happens is currently a mystery. “We don’t know how or why” so many infected people are “cured” naturally, Dr. Revill admitted, but it gives him and his colleagues hope that the numbers can expand once more and better treatments for HBV infection are available.