Can Enbrel and Remicade Induce MS?

According to a report in the journal, Arthritis & Rheumatism (2001;44:2862-2869), two of the biggest moneymakers in pharmacology may be even more expensive than the price on the bottle. FDA researchers warn that in a small number of cases, both Enbrel (etenercept) and Remicade (infliximab) have been associated with an effect that mimics multiple sclerosis. Very likely, the symptoms derive from the same cause: erosion of myelin, the natural insulation around the nerves. In the case of MS, as the myelin sheath deteriorates, nerve cells "short-circuit," losing the ability to fulfill their intended functions. Symptoms of the disease range from numbness and muscle weakness to loss of motor skills, paralysis and death.

It has not yet been determined by what mechanism the two drugs can sometimes produce this result in patients being treated for rheumatoid arthritis. However, both pharmaceuticals have been widely reported to be associated with increased levels of infection. There is growing evidence that MS, like rheumatoid arthritis, may have an infectious etiology. The connection between Enbrel and this disorder was first posited by neurologists at Georgetown University Medical Center, based on their observations of a male arthritis patient, 48, who complained of confusion and difficulty walking. No myelin loss was visible in an MRI brain scan, but a subsequent brain biopsy showed some nerve fiber damage. The man had been on Enbrel for only 4 months.

Later, researchers found reports of 17 other Enbrel patients and two more on Remicade with the same symptoms. In every case, the MS symptoms improved or remitted when the use of the drugs was terminated. One patient started Enbrel again after the nerve damage reversed, only to have it return.

The FDA recommends that patients receiving Enbrel or Remicade be monitored by their physicians for such neurologic symptoms as confusion, numbness, changes in vision and difficulty walking. So far, it's still perfectly legal for a doctor to prescribe either drug to RA patients regardless of any other diagnosis. However, the medical director of the Arthritis Foundation told Reuters, "I think the medical community would be of the view that these drugs should not be used in people in known demyelinating diseases like multiple sclerosis."