Viron completed its Phase I clinical trial with VT-111 in healthy volunteers in the U.S. No serious adverse events were reported and VT-111 was well tolerated at all dose levels. VT-111 elicited no adverse clinical effect on hematology, coagulation or clinical chemistry parameters, and was not immunogenic.

VT-111 has undergone extensive pre-clinical testing in four species to screen for signs of toxicity. In a pivotal monkey toxicology study in which VT-111 was administered by a single daily bolus injection for 14 consecutive days at doses significantly higher than the anticipated human dose, VT-111 elicited no adverse clinical effect on body weight, food consumption, hematology, coagulation or clinical chemistry parameters, organs weights, macroscopic observations at necropsy, or tissue architecture. In a separate cardiovascular safety study in monkeys, VT-111 administration up to 50 times the proposed clinical dose (750 µg/kg) had no effect on heart rate, blood pressure or the electrocardiographic complex.

All proteins have the potential to induce an immune response. Based on a comprehensive set of data, Viron believes that immunogenicity will not be a serious threat to its development compounds. Since immunogenicity would negatively affect the potency of these viral proteins, it stands to reason that viruses have evolved to produce anti-inflammatory drugs that have extremely low immunogenicity. Similarly, viral proteins such as VT-111 have evolved to produce highly potent anti-inflammatory signals at low doses, which also reduces the immunogenic potential of the drug.