June 12 (HealthDay News) -- High doses of a drug used to fight cancer may reduce disease activity and disability in people with aggressive multiple sclerosis, results of a small trial suggest.

In relapsing-remitting MS, the most common type of the disease, patients experience periods of symptoms followed by stretches of symptom-free remission when they used the immunosuppressant drug cyclophosphamide.

In the two-year open label trial that included nine patients with aggressive relapsing-remitting MS, six men and three women with the average age of 35, received 50 milligrams per kilogram per day of cyclophosphamide intravenously for four consecutive days.

After an average of 23 months follow-up, the patients experienced an average 39.4 percent reduction in disability and an 87 percent improvement on scores of physical and mental function. MRI imaging showed a decrease in the average number of MS-related brain lesions, from 6.5 to 1.2 lesions.

"High-dose cyclophosphamide (sold commercially as Cytoxan or Neosar) induced a functional improvement in most of the patients we studied," wrote lead author Chitra Krishnan of the Bloomberg School of Public Health at Johns Hopkins University in Baltimore, Md. "In many of those patients, the functional improvement was sustained through the length of the study (up to 24 months) despite the absence of any immunomodulatory therapies beyond the initial high-dose cyclophosphamide treatment," she concluded.

The study was published online this week in the journal Archives of Neurology and was expected to be in the August print issue.

Cyclophosphamide has been used in combatting a number of cancers, including lymphomas, multiple myeloma, leukemia, mycosis fungoides, neuroblastoma, ovarian carcinoma, retinoblastoma and breast cancer. The drug affects the function of immune cells known as T and B cells.

Multiple sclerosis is an inflammatory disease in which the protective coating covering nerve cells degenerates. Autoimmune dysfunction -- in which the body attacks itself -- is believed to be linked with MS.

"This immunoablative regimen (an immune-related therapy involving the destruction of a cell population) of cyclophosphamide for patients with aggressive MS is worthy of further study and may be an alternative to bone marrow transplantation," the study authors concluded.

SOURCE: JAMA/Archives journals news release, June 9, 2008