FDA Panel Backs Cancer Drug for Multiple Sclerosis

From the WebMD Archives

Jan. 28, 2000 (Washington) -- People with one form of multiple sclerosis (MS) got one step closer to finally having at least one FDA-approved treatment option, as an advisory panel recommended Friday that the FDA approve Seattle-based Immunex Corporation's chemotherapy drug mitoxantrone (Novantrone).

MS is a chronic, debilitating disease of the central nervous system. Symptoms such as tingling, numbness, muscle weakness, and stiffness result from loss of the myelin sheath, which insulates the nerve fibers of the brain and spinal cord. This leads to scar tissue formation, interfering with the nerve's ability to transport messages from the brain to the body.

About 350,000 Americans have MS. Novantrone works on the form of the disease that is chronic and gets worse over time. There's another form of the disease, in which symptoms flare up and then ease or even disappear for months or years.

Mitoxantrone is currently used in the U.S. for the treatment of prostate cancer and a form of leukemia.

In support of this new use of the drug, Immunex submitted results from two studies. The application also contained safety data from 500 individuals with MS, who had received at least one dose of Novantrone in a clinical setting.

In one study, Novantrone resulted in significant clinical improvement in symptoms in over 60% of the MS patients. In addition, 70% had fewer relapses of the disease. The other study showed that the drug slowed progression of the disease, as measured by an MRI.

One important issue was the safety of the drug. When used to treat cancer patients, the drug has been shown to cause heart failure and a weakened immune system. Both of these adverse effects were seen in a small number of patients in the studies. Speaking on behalf of the committee in response to an FDA question about the potential for heart problems, "I think the likelihood is very low," said James Grotta, MD, professor of neurology at the University of Texas. In addition to heart failure, the FDA also tracked five reports of liver failure.

The committee also took into consideration the results of a European study, where the drug was associated with 20 deaths. However, the patients in that study took the drug for nearly four years, whereas Novantrone would be limited to two years of use in the U.S.