Innogenetics is developing InnoVac-C, a vaccine using HCV E1 and E2 envelope protein sequences to produce immunity.
These proteins help protect the virus from the immune system and let the virus enter into liver cells. E1 and E2 are
the only HCV proteins that can be attacked by the immune system, so they are prime targets for vaccine development.
Phase I clinical trials involving 20 healthy males have been completed. The product was well tolerated and
induced an immune response in 19 of the subjects, antibodies in 17, and cellular immunity in 18. Adequate cellular
immune response is usually considered to be a key factor in the clearance of a viral infection. In January 2001,
Phase II studies began to test safety and efficacy in patients with chronic Hep C, genotype 1. The patients received 5
injections, plus a booster. The vaccine did not show decreases in viral load, but ALT levels improved, and immune
responses were noted. In a further study in the same patients, another 6 injections were given, and immune responses
were better still, while biopsy scores showed that fibrosis was halted, and in some cases, improved. A new extension
of the study in the same patients began in January 2003, and is expected to generate results in 2004. A European,
Phase IIb clinical trial started in the first quarter of 2003, with 150 non-responders, or difficult-to-treat patients.
In addition to these trials, pre-clinical trials in animals with a prophylactic E1 vaccine look promising, and further
studies will have reports available in the first half of 2004.