Viron's Phase 2a trial for VT-111 meets primary, secondary endpoints in ACS patients

- VT-111 results demonstrate statistically significant reduction in two key biomarkers of cardiac damage -

Viron Therapeutics Inc. today announced that the results of Viron's Phase 2a trial for VT-111 were published today in Circulation: Cardiovascular Interventions. In the study led by Dr. Jean-Claude Tardif, Director of the Research Centre at the Montreal Heart Institute, VT-111, also known as Serp-1, met both its primary and secondary endpoints of safety and biological activity in Acute Coronary Syndrome (ACS) patients receiving coronary stents. VT-111 is a protein produced by the myxoma virus that allows the virus to lower its host's inflammatory response to infection.

"Although the use of cardiovascular stents have dramatically improved the outcomes for patients with occlusive coronary artery disease, numerous studies have shown that the procedure itself can cause what is termed peri-procedural myocardial injury (PMI)," said James Rae, CEO of Viron. "A recent review in the European Heart Journal shows that 30% of patients receiving coronary stents sustain an injury to the heart tissue arising from the procedure itself and the biomarkers most useful in measuring this cardiac injury are CK-MB and Troponin I. Viron's Phase 2a trial showed a statistically significant, dose-dependent reduction in these two key biomarkers of cardiac damage, at multiple timepoints, with a particularly potent effect in the first 24 hours after the placement of the stent. If the incidence of PMI was reduced, clinical outcomes would improve for many of the almost 3 million patients each year that receive cardiac stents in North America and Europe."

Numerous studies have shown that a rise in CK-MB and Troponin I in the first 24 to 48 hours after placement of a stent is evidence that the procedure has caused damage to the heart tissue, putting these patients at a much higher risk of negative clinical outcomes. A therapy to reduce PMI would need to impact these biomarkers in that critical first 24 hours.

VT-111 also showed a strong trend towards reducing Major Adverse Cardiac Events (MACE; a clinical endpoint comprised of myocardial infarction, revascularization, coronary artery bypass graft (CABG) or death) in the higher dose group, with no MACE events at the six month follow-up, compared to the placebo group, which had 17% MACE rate.

"Reductions in these cardiac enzymes are very encouraging given the strong correlation between a rise early after the procedure and the probability that those patients will experience a subsequent clinical event," said Dr. Carl Pepine, past president of the American College of Cardiology. "These data are even more encouraging when you note that the high dose group saw no MACE compared to the 17% MACE rate seen in the placebo arm of the study. I am very interested to see a larger study of VT-111 in this patient population. It may also be possible for VT-111 to have an even greater impact if delivered in doses above the top dose of 15 micrograms per kilogram (µg/kg) tested in this trial."

Starting immediately before stent placement in this double-blind, placebo-controlled Phase 2a trial, 48 patients received intravenous doses of placebo or VT-111 once daily for three days. Subjects were then followed for six months for evaluation of safety and a variety of inflammatory and cardiac enzyme biomarkers.

Viron plans to continue further clinical testing in 2011 with a fully glycosylated version of the original drug that has shown significantly enhanced efficacy in animal models over the original drug with a similarly high margin of safety.