BioWorld International Correspondent
PARIS - Innogenetics NV reported mixed results from Phase IIb trials of its E1 viral protein-based therapeutic vaccine for chronic hepatitis C.
The data confirmed the safety and tolerability of the vaccine and its ability both to stimulate immune responses and to stabilize liver fibrosis in patients treated with the vaccine. But the control group showed a slower deterioration of the liver (fibrosis) than in previous literature and there was no statistically significant difference between the vaccine-treated patients group and the placebo group.
The company said the unexpectedly small difference between the groups could have been due to parameters such as dosing or the length of treatment. The main investigators suggested that the treatment period of one of the trials, which is ongoing, be extended by at least another 15 months. Innogenetics intends to follow that recommendation, providing it is approved at the full investigators' meeting at the end of June.
The company's CEO, Frank Morich, said he "remains confident about the potential of our therapeutic E1 vaccine. It remains our lead project within our therapeutic vaccine portfolio." But he acknowledged that its development program has been set back by more than a year. "The next crucial milestone for this program is now expected for approximately mid-2007," he said.
Two Phase IIb trials were differentiated by the dosage and the origin of the vaccine material. The first involved Innogenetics' HCV E1 vaccine, which incorporates mammalian-derived E1 material and was administered at 20 mg. The second trial, still ongoing, involves administration of a vaccine incorporating yeast-derived E1 material (the HCV E1y vaccine) at 50 mg.
An earlier Phase IIa trial confirmed the strong immune response in patients treated with the vaccine. Liver fibrosis was stabilized after 17 months, and there even was a regression of fibrosis after three years.
Innogenetics' chief therapeutics officer, Guy Buyens, said "the behavior of the placebo group was quite unexpected." Pointing out that "the vaccine candidate again induced strong immune responses and reproduced the results of the Phase IIa study on liver histology," Buyens said the extension of the second Phase IIb study with its higher dosing would "optimize the study design for proof of efficacy."
At the end of March, Innogenetics reported positive results from a Phase I trial in the U.S. of a therapeutic vaccine candidate for hepatitis B acquired from Genencor International Inc. A week earlier, the company had raised €34.5 million through a private placement of 2.7 million new shares with institutional investors, although it had initially planned to raise no more than €20 million.