Anadys Pharmaceuticals, Inc. reported at the 10th international meeting on hepatitis C and related viruses in Kyoto, Japan that interim results from an ongoing clinical trial of isatoribine (ANA245) demonstrate that the drug is safe and well tolerated. Although efficacy is not a stated objective of the Phase 1B clinical trial and the number of patients was small, results showed that isatoribine is biologically active in adults with chronic hepatitis C virus (HCV) infection. Isatoribine, which is believed to act by a mechanism of action involving interaction with Toll-like receptor 7 (TLR7) and stimulate the patient's own immune system, is one of a new class of drugs being developed by Anadys to regulate innate immunity, combat hepatitis C virus infection and overcome limitations of current therapies. Devron R Averett, PhD, Anadys' senior vice president of drug development presented the data at the meeting.
In an oral presentation at the meeting, Dr Averett presented data from the first three of four cohorts of an ongoing open-label, dose-escalation Phase 1B clinical trial of isatoribine administered intravenously over a period of seven days to thirteen adults with chronic hepatitis C infection. The trial was designed to determine the safety, tolerability and pharmacokinetics of isatoribine. Results corroborate and extend previously disclosed safety, tolerability, and pharmacokinetic data derived from single doses of isatoribine in healthy volunteers. The study revealed that no serious adverse events were observed with a low frequency of mild to moderate adverse events.
The data generated in this clinical trial shows that isatoribine is biologically active in adults with chronic hepatitis C infection based on statistically significant changes in biologic markers; one such biological marker that was measured in the trial was the level of 2'-, 5'-oligoadenylate synthetase (OAS), which increases during interferon-alpha treatment and is thought to mediate antiviral effects. Also, a trend toward reduction of viral load over the seven-day course of treatment was seen.
"The interim results of this ongoing Phase 1B trial indicate that isatoribine is well tolerated and biologically active in patients with hepatitis C," said Dr Averett. "We observed induction of a recognized biological marker for interferon-alpha activity in patients receiving isatoribine, and the magnitude of this induction appears to be dose related."