PHILADELPHIA (AP) -- Doctors at Drexel University reported promising results using huge doses of a potent chemotherapy drug in treating autoimmune diseases including multiple sclerosis, though an MS researcher said more patients and time are needed before any victory is declared.

The drug, cyclophosphamide, is given to patients at such high doses that most or all of the person's disease-fighting immune cells are destroyed.

The patient's stem cells within their bone marrow survive the drug's onslaught, the doctors say, and are stimulated with drugs to rebuild the immune system from scratch -- but without the bad triggers that cause the body to attack its own cells.

"Once the immune cells are destroyed, they come back no longer recognizing the stimulus that brought them on," Dr. Isadore Brodsky, director of hematology and oncology at Drexel's Hahnemann University Hospital, said Monday. "The immune system comes back naive, so it's tolerant of whatever trigger caused the autoimmune response."

So far, just six MS patients have completed the chemotherapy, which is administered over three to five days, and the first patient finished it just six months ago. All were determined to have advanced cases of MS and had tried at least three other types of therapies, from steroids to immune-suppressing drugs, with no benefit, said Brodsky, who is developing the treatment with his son, Dr. Robert Brodsky at John Hopkins University.

Stephen Reingold, vice president for research with the National Multiple Sclerosis Society, said that the results are too preliminary to draw any conclusions.

"Any study that claims extraordinary benefits based on a short term, uncontrolled study with a small number of patients has to be treated cautiously," Reingold said. "The big questions here are how long it lasts and whether it leaves you open for infections and other problems."

Autoimmune diseases typically are suppressed with the drug interferon, steroids, radiation and other chemo drugs that stop reproduction of the confused cells that treat the body's own cells like they're foreign invaders. Brodsky's work involves killing the immune cells, not merely suppressing their growth.

Patient follow-up and more research is necessary but the initial results were "striking and unexpected," said Dr. Robert Schwartzman, a Hahnemann neurologist who has referred patients to Brodsky for treatment and is evaluating them afterward.

Several of his patients who had autoimmune-related cognitive problems, difficulty walking, or other coordination troubles have seen much of their symptoms disappear in as little as three to six weeks, Schwartzman said.

Terry Davis, 47-year-old teacher from Pennsville, N.J., said she had the high-dose chemo treatment in September after other therapies failed and no longer needs a cane or walker to get around. She lost her hair, experienced severe nausea and had a "flare up" of her MS symptoms after the treatment, all of which have since subsided, she said.

"The chemo was rough but it was well worth it. I can walk unassisted," she said. "There are no words to describe how dramatically this treatment has affected the quality of my life, physically and mentally."

Brodsky has used the chemotherapy drug since 1997 on more than 300 patients with autoimmune diseases of the blood, peripheral nervous and neuromuscular systems, and extended it to the handful of MS patients starting last fall.

Results from the study, which was approved by the FDA, were presented at a symposium in Philadelphia last week.

Copyright 2004 The Associated Press. All rights reserved.