Trial results for spi-VECTM oral immunotherapeutic vaccine reported.

2004 DEC 1 - (NewsRx.com & NewsRx.net) -- Microscience announced further significant results from a phase I clinical study of its spi-VECTM oral immunotherapeutic vaccine designed for the treatment of subjects chronically infected with the hepatitis B virus (HBV).

The trial met its primary objectives and successfully demonstrated safety and immunogenicity, supporting the vaccine's continued development as a therapeutic for chronic HBV carriers.

A phase I, open-label, dose-escalating study was performed in 30 healthy adult volunteers to evaluate the safety and immunogenicity of a candidate oral immunotherapy given on two occasions, 56 days apart.

The primary aim of the study was to assess safety and to determine the cellular immune responses against hepatitis B core antigen ("HBcAg") raised by two dose levels of this novel vaccine. It is known that a cellular immune response is critical for an immunotherapy to be effective against this life-threatening infection.

The vaccine was shown to be safe and well tolerated. The immunological data have demonstrated that all subjects mounted a T-cell proliferative response to both the HBcAg and to groups of peptides representing the whole sequence of HBcAg, indicating that the antigen had been successfully delivered to the immune system in all subjects.

In addition, 95% of responders in the high dose group elicited a Th1-biased response characterized by the secretion of gamma interferon and the absence of IL-5 secretion by stimulated T-cells. Th1 responses are known to play an important role in the promotion of viral clearance in chronic hepatitis B. The ...