An old drug shows new promise for patients with nondystrophic myotonias

October 03, 2012

By Andy Hyland

Aaron Chronister
After receiving mexilitene in a clinical trial, Aaron Chronister's nondystrophic myotonia symptoms improved significantly.

A decades-old drug previously used to treat abnormal heart rhythms is showing new promise in the fight against a rare neurological disorder, according to research conducted at the University of Kansas Medical Center.

People who have nondystrophic myotonias are rare. The disorders are estimated to affect about 1 of every 100,000 people. The disorders aren't life-threatening but can be debilitating as patients' muscles contract and won't relax, causing functionally limiting pain, stiffness and fatigue.

Richard J. Barohn, M.D., chair of the KU Medical Center Department of Neurology, led the randomized, double-blind, placebo-controlled study at the KU Medical Center site. He and his collaborators reported their research in the Oct. 3 edition of the Journal of the American Medical Association (JAMA), and significantly expanded on the mostly anecdotal data collected on the disorders before the study. An accompanying editorial praised the research as "a trial triumph for rare disease networks."

Barohn said the drug had been sitting on the shelves in pharmaceutical companies since the 1970s after newer and better heart arrhythmia treatments came along.

Barohn and his colleagues in the Consortium for the Investigation of Neurologic Channelopathies (CINCH) found that patients who took the repurposed drug, mexilitine, reported that their stiffness improved, they had less pain and they also performed better on handgrip tests.

"Our data showed that the impact of the drug was dramatic," Barohn said. "It was unbelievable. Almost everything we tested got better when patients took mexilitene and got worse when they took a placebo."

Aaron Chronister, a 36-year-old Kansas City, Mo., resident, was diagnosed at the Mayo Clinic about 18 years ago, he said, after initially being misdiagnosed elsewhere.

"They didn't have any medication for it at the time," he said. "My muscles didn't ever relax. They were squeezing constantly."

Today, after receiving mexilitene, his symptoms aren't completely gone, but they have improved significantly, he said. Chronister is known on the national competitive barbecue circuit for helping to create the Bacon Explosion recipe, which went viral on the Internet and was featured in The New York Times, CNN and Good Morning America.

"Don't eat too much of it," Chronister said of the bacon-wrapped and bacon-stuffed Italian sausage concoction.

Today, he works from home, directing online properties for CBS Interactive. He still participates in barbecue competitions from time to time, but has scaled back recently to spend more time with his family.

He said his condition is genetic, so he participated in the clinical trial at KU Medical Center not just for him, but also to contribute to scientific knowledge for the rare disease for others with experiences like his own. Though his daughter doesn't have the condition, he knows that future generations might, he said.

The first author on the study is Jeffrey M. Statland, M.D., a research fellow at the University of Rochester Medical Center. Statland assisted Barohn and his colleagues in developing the project when he was a research assistant and then neurology resident at KU. After finishing his residency at KUMC in 2010, Statland stayed involved with the project while at Rochester and eventually took the lead in assembling the final manuscript.

The study involved 59 patients and was supported by the National Institutes of Health-funded Rare Disease Clinical Research Network and a Food and Drug Administration program that supports research into rare diseases. It was conducted at seven sites in four countries.

 "We're hoping that these drug companies will see this research and hopefully will be inclined to make this drug more available," Barohn said.

Last modified: Nov 01, 2012