One of the fascinating aspects of DNDN's antigen cassette technology, which uses a chemical linker to fuse an antigen with GM-CSF, and CEGE's GVAX, which genetically engineers metastatic cancer cell lines to express GM-CSF in vivo and irradiates them to stop in vivo prolifertaion, is that their different approaches to coupling GM-CSF, an immune stimulant, appears to be so critical to success. CEGE showed slides at the FDA/NCI workshop that showed that merely dosing GM-CSF as a separate recombinant protein at the same time, as the failed Canvaxin melanoma vaccine tried, not only doesn't work, but that GM-CSF if overdosed can potentially act as an immune suppressor. DNDN tried dosing just the fusion protein in its Ph2 trials, but that also didn't work well. It would be an interesting experiment to see if pulsing GVAX cells ex vivo with a patient's immune cells per the "method of Hsu" used by DNDN offers any advantages over injecting patients with the GVAX cells. All JMHO.
