Immune cells to fight leukemia.

A cancer "vaccine" that uses small proteins found in abundance on the surface of leukemia cells shows strong signs of keeping the blood cancer at bay if given when the disease is in remission.

Cancer vaccines attempt to rally a person's immune cells to fight a malignancy. Researchers gave the vaccine to 13 leukemia patients in remission and 53 others who had active disease. All the patients had received other drugs previously. Although some were in remission, none was a good candidate for continued standard treatment because all had advanced leukemia, says study coauthor Muzaffar H. Qazilbash, a hematology oncologist at the M.D. Anderson Cancer Center in Houston.

The cancer vaccine had shown early promise in stimulating production of immune T cells that attack leukemia cells, which display excess amounts of two enzymes--proteinase-3 and neutrophil elastase (SN: 1/4/03, p. 13). Patients received three to six injections of the vaccine at 3-week intervals.

The 13 patients in remission at the outset fared best, averaging nearly 9 months of continued remission. One patient has avoided any relapse for 6 years after getting the vaccine, another for 5 years, Qazilbash says. Patients who were still fighting active disease at the time they got the cancer vaccine benefited much less, averaging only about 3 months of remission.

The vaccine works only in leukemia patients who carry a specific kind of immune protein called HLA-A2. About 40 percent of people have it, Qazilbash says.--N.S.