Immutep completes Ph I with ImmuFact

French bioparmaceutical group Immutep says that its lead product, ImmuFact IMP321, has successfully completed two large randomized Phase I clinical studies assessing its safety, tolerability and immunogenicity in normal healthy volunteers. The product is a potent natural human T cell immunostimulatory factor designed to amplify the T cell immune response in therapeutic vaccines.

The randomized single-blind escalating-dose Phase I studies were conducted in healthy individuals with ImmuFact IMP321 alone and combined with antigens. Two well-defined standard types of antigens were used: soluble influenza virus antigens (a flu vaccine) and the particulate hepatitis B surface antigen. Recruitment of 108 healthy volunteers started in April 2005 and was completed in October 2005. The doses studied ranged from one injection of 3mcg up to three injections of 100mcg.

The studies showed that IMP321 is well tolerated with no adverse events at all dose levels either alone or associated with potent antigens. Importantly, there were no anti-IMP321 antibodies detected which means that repeat dosing should be possible including protocols calling for six or more injections. Analysis of the immune responses showed that, even with such potent antigens, IMP321 gave rise to an increase in the number of responders, associated with a substantial increase in antigen-specific T cells and a shift to the Th1 response required for therapeutic vaccines.