More MS news articles for July 2001

Derivative of lethal botulism relieves movement trouble

Toxin Useful Because It Can Paralyze

http://www0.mercurycenter.com/premium/scitech/docs/botox17.htm

Published Tuesday, July 17, 2001, in the San Jose Mercury News
BY MARIE MCCULLOUGH
Knight Ridder Newspapers

Botulinum toxin is one of the deadliest molecules known -- and one of the most versatile medicines.

Almost 60 years after researchers purified the poison as a possible biological weapon, it has at least 90 therapeutic uses, and counting.

The drug -- sold under the brand names Botox and Myobloc -- has been a godsend for people with movement and voice disorders, crossed eyes, excessive sweating, writer's cramp and, as anyone who is familiar with the latest in cosmetic treatments knows, deep wrinkles.

More recently, it has been successfully used to relieve migraine headache, drooling in Parkinson's patients, and even clubfoot in babies.

In tests, it is now showing promise for treating the jaw disorder known as TMJ, spasticity in children with cerebral palsy, and chronic lower back pain.

"It's got quite a range of uses," said Christine Cassiano, a spokeswoman for Allergan, the Irvine maker of Botox. "And in general, it's such a safe treatment."

No one could have imagined the toxin's therapeutic value a century ago when botulism -- a paralyzing illness that ends in respiratory failure -- was first recognized in Europe.

The name came from the Latin word "botulus," meaning sausage, because many cases were caused by home-fermented sausages.

Now, doctors know that the toxin is produced by a group of bacteria, Clostridium botulinum, that can multiply not only in food but in a wound or even a baby's intestine.

Ironically, the toxin's ability to cause paralysis by disabling the nerves that control muscles is what makes it medically useful.

In the 1980s, scientists using a highly purified, diluted form of the toxin showed that minute amounts could be injected into selected muscles to relieve involuntary contractions, including strabismus (cross-eye or walleye), blepharospasm (uncontrollable eye closure) and hemifacial spasm (eye twitch).

"It worked dramatically and better than any combination of medications," recalled neurologist Matthew Stern, director of the Movement Disorders Program at the University of Pennsylvania in Philadelphia.

Stern and others began expanding use of the toxin to treat a variety of "dystonias" -- abnormal muscle cramping. About 300,000 Americans suffer from these debilitating neuromuscular disorders, which can affect any part of the body, including the neck, the hand (writer's cramp), the leg, the foot, or even the voice box (larynx).

Sometimes, the cramping is linked to multiple sclerosis, cerebral palsy or a stroke. Other times, there is no apparent cause.

Rick Lansil, a retired Princeton Theological Seminary executive in New Jersey, assumed for many years that his labored, breathless voice (imagine speaking after running up three flights of stairs) was due to stress and anxiety.

Then, nine years ago, he read an article about "vocal dysphonia" and a new treatment: botulinum toxin.

"I cried when the doctor said, `I want you to know it's not psychological, it has nothing to do with stress, and you have done nothing to cause this,' " recalled Lansil, who lives in Bucks County, Pa., outside Philadelphia.

The toxin is not a panacea for the maladies it treats. The effects typically wear off in three to four months, and a few patients develop resistance to Botox, made with toxin type A -- although now they can switch to Myobloc, a newer drug made by Elan Pharmaceuticals using toxin type B.

The Food and Drug Administration has approved botulinum toxin only for blepharospasm, strabismus and, last December, for cervical dystonia, a painful contraction of the neck muscles. But Allergan is seeking approval for other indications, and doctors have discretion to use it "off-label" for other purposes.

© 2001 The Mercury News.