Progenipoietin plus melanoma tumor antigen vaccine stimulates immune response.

2003 JUN 11 - (NewsRx.com & NewsRx.net) -- by Maria G. Essig, MS, ELS, senior medical writer - Results from a phase I clinical trial indicate that administration of progenipoietin and a vaccine containing melanoma tumor antigens stimulated in a potent immune response in patients who had undergone resection for malignant melanoma.

"The melanoma tumor antigen epitope peptides MART-1[subscript]26-35(27L), gp100[subscript]209-217(210M), and tyrosinase[subscript]368-376(370D) were emulsified with incomplete Freund's adjuvant and administered with SD-9427 (progenipoietin), an agonist of granulocyte colony-stimulating factor and the FLT-3 receptor, to evaluate the toxicities of and immune responses to this regimen as primary end points and time to relapse and survival as secondary end points," reported Vinod Pullarkat and colleagues at the University of Southern California, Stanford University, and Pharmacia.

The researchers administered the peptide vaccine plus adjuvant once a month for six months and once six months later to 15 patients who had undergone resection for stage III and IV melanoma. Subcutaneous injections of 10, 20, or 40 microgram/kg of progenipoietin were provided for three days prior to each vaccination and for seven days after each immunization.

Of 12 patients given skin tests to detect immune responses to the tumor antigens, 6 developed a positive response to at least one of the antigens.

"Seven of 10 patients tested demonstrated an immune response to at least one peptide when evaluated by IFN-gamma release assay and ELISPOT assay after vaccination, as did 11 of 12 patients analyzed by MHC-peptide

tetramer assay," stated the investigators.

One of the patients has died and four have relapsed within the 20-month median follow-up period.