Jun 11, 2008

Small Study Suggests High Dose Regimen of Cancer Drug Cyclophosphamide Reduces MS Disease Activity

A small, uncontrolled clinical trial involving nine people with relapsing-remitting MS suggests that a regimen of high-dose chemotherapy (cyclophosphamide given intravenously) significantly reduced disability and MRI-detected disease activity in most, and resulted in sustained remission in some, who had been followed for an average of 23 months. Larger, controlled trials are needed to establish the safety and long-term effectiveness of this therapy to treat MS. The study, by Johns Hopkins University researchers Chitra Krishnan, Douglas Kerr and collaborators, was funded in part by the National MS Society. Results were published early online on June 9, 2008 in the Archives of Neurology (Vol. 65, No. 8).

Background:

Multiple sclerosis involves immune-system attacks on the brain and spinal cord. The partially effective therapies available for treating MS focus on modulating these immune attacks. Wholesale immune suppression is also sometimes used in attempts to treat aggressive MS. One of several such drugs used to kill immune cells is cyclophosphamide, a powerful chemotherapy that has been used to treat many types of cancer, and has also been used “off label” to treat MS with mixed results.

This Study:

Nine individuals with active, relapsing-remitting MS were included in this pilot safety study. Eight had used available immune-modulating therapies without success, and one had refused approved therapy. Each received high-dose, intravenous cyclophosphamide for four days to kill white blood cells (immune cells) circulating in the bloodstream. The stem cells in the bone marrow are tolerant of cyclophosphamide and are for the most part spared. After the infusions, the patients were given a growth factor (granulocyte colony-stimulating factor) to stimulate the growth of immune cells in the bone marrow. The patients’ immune systems were reconstituted from bone marrow stem cells in 10 to 17 days.

The authors report that the nine participants were followed for an average of 23 months, during which time no unexpected serious adverse events occurred. Most experienced stabilization of disability or significant reductions in disability (as measured by the standard EDSS measure). Five of the patients had a sustained decrease (meaning improvement) of greater than one point on the EDSS. There was an 81.4% reduction in the average number of active (enhancing) MRI brain lesions, compared to pretreatment scans. Two of the patients experienced MS relapses and were given immune-modulating therapy.

This small, uncontrolled study provides further evidence that some people with very active forms of MS, refractory to other medications, respond favorably to high-dose immunosuppressive therapy. This type of aggressive immune suppression carries risks, but in capable hands these risks can be largely circumvented.

In the future, larger, controlled trials of high-dose cyclophosphamide should help determine how this treatment regimen might be most beneficial for people with MS.