GM-CSF lookalikes

Cancer vaccines being developed by The Immune Response Corp. and Cell Genesys Inc. may appear nearly identical, as both products are engineered to secrete the cytokine GM-CSF. But there are differences between the products that could affect their versatility in the clinic. IMNR's vaccine contains irradiated glioma cell lines mixed with cultured fibroblasts engineered to secrete granulocyte-macrophage colony stimulating factor, while CEGE's GVAX is comprised of irradiated tumor cells which themselves have been genetically modified to secrete GM-CSF.

According to IMNR, which last week began U.S. Phase I testing of its product to treat malignant brain tumors, separating tumor cells from GM-CSF secretion "allows us to use our fibroblast in multiple cell lines - therefore it's a platform technology," said Richard Bartholomew, executive director of research operations. Furthermore, said Bartholomew, keeping the two separate allows for differential dosing of cytokine and tumor cell...