BioCentury
ARTICLE | Product Development

Designs on NS5b

October 6, 2008 7:00 AM UTC

The HCV polymerase non-structural protein 5b has been known for many years, but to date no company has successfully targeted it because of toxicology issues or lack of potency. Anadys Pharmaceuticals Inc. believes its structure-based drug design and medicinal chemistry approaches have overcome those problems. Late last month, the company reported preliminary results from a Phase I trial of its NS5b inhibitor, ANA598.

NS5b is essential for viral replication, making it an attractive target. Yet its history is littered with failed antagonists, including VP 50406, a non-nucleoside NS5b inhibitor from ViroPharma Inc. and Wyeth. The partners halted development in 2001 after it failed to show significant antiviral activity in Phase IIa testing. In April, the partners discontinued development of another HCV compound, HCV-796, because of hepatotoxicity in a U.S. Phase II trial. HCV-796 was a non-nucleoside viral polymerase inhibitor...