Cancer Drug Fails for Inner Ear Disease
Study rules out use of methotrexate for rare autoimmune condition
TUESDAY, Oct. 7, 2003 (HealthDayNews) -- Patients suffering from an extremely rare kind of hearing loss won't benefit from a drug that helps people with a similar condition that causes arthritis, new research finds.
People with autoimmune inner ear disease did no better on a drug called methotrexate than those who took a placebo.
"It's certainly disappointing," says study co-author Dr. Jeffrey Harris, a professor who specializes in the ear, nose and throat at the University of California at San Diego.
However, the failure of methotrexate won't doom all the disease's sufferers, estimated at about 1 percent of those with hearing difficulties. More than half of people who develop autoimmune disorders in their ears go on to recover much of their hearing thanks to another drug treatment. Others can turn to implants of special cochlear hearing aids.
Doctors and scientists don't know why the ears of people of all ages -- especially those over 50 -- develop autoimmune disease. For some reason, the immune systems in their bodies become confused and begin to attack the inner ear as though it is a dangerous invader.
The immune system's attack cells "are being activated by something, an antigen or a virus or things we don't understand," Harris says. "The cells come in to it and clear it out from the body, but they don't know they're hurting the ear at the same time."
As a result, the inner ear then becomes inflamed, and hearing can start to disappear. "You feel that your hearing is going down in one ear, and you may or may not have dizziness," Harris says. "Within months, the opposite ear starts having problems as well. You can go from normal hearing to where one ear becomes completely useless in terms of hearing, and the other ear becomes increasingly more dysfunctional."
Experts said the best current treatment for autoimmune inner ear disease is prednisone, a steroid that suppresses the immune system and often lets the ear recover. But prednisone can cause a variety of side effects, including fat deposits that appear on the back and on the face, giving patients an embarrassing "moon face" appearance, Harris says.
Prednisone can also weaken bones and elevate blood sugar levels, causing a condition similar to diabetes.
If prednisone fails to work, patients often turn to cochlear implants. Perhaps the most famous person to receive such an implant is radio talk-show host Rush Limbaugh.
In the new study, researchers treated 116 autoimmune inner ear disease patients with prednisone for one month. The findings appear in the Oct. 8 issue of the Journal of the American Medical Association.
Sixty-three percent of the patients on prednisone reported better hearing in one ear, while 37 percent responded in both ears.
Those whose hearing improved significantly went on to receive a placebo or methotrexate, a cancer drug that is also successfully used to dampen the overactive immune systems in people who have rheumatoid arthritis. Of those 67 patients, however, 61 left the study because their hearing deteriorated. The methotrexate simply did not work, Harris says.
Despite its disappointing results, the research still has value, says Dr. Roberto Cueva, who treats hearing problems at the Southern California Permanente Medical Group. "The study really helps eliminate the consideration of methotrexate as a useful treatment. Even negative studies help us pursue treatments for different conditions, so we don't keep going down a blind alley and not making progress."