Lithium doesn't delay progression of amyotrophic lateral sclerosis (ALS), or Lou Gehrig's disease, and shouldn't be used to treat patients with the disease, researchers say.
The findings from a new study contradict promising results from a small pilot study that led to a high level of off-label use of lithium to treat people with ALS, a fatal motor neuron condition.
Currently, there is no cure for ALS. The only approved drug for treatment of ALS is riluzole, which has been shown to extend patients' lives by an average of three months.
In the new study, American and Canadian researchers randomly assigned 84 ALS patients to receive either riluzole and a placebo or riluzole and lithium. The trial was stopped early after initial findings suggested that lithium would have little or no effect.
"Although a modest benefit of lithium was not ruled out by the study . . . we found no evidence that lithium in combination with riluzole slows progression of ALS more than riluzole alone," wrote Dr. Swati Aggarwal from Massachusetts General Hospital in Boston and Dr. Lorne Zinman of Sunnybrook Health Sciences Center in Toronto, and colleagues.
"At this time, there remains no convincing evidence for the use of lithium as a treatment for patients with ALS," they concluded in a statement.
Lou Gehrig's disease attacks the brain and spinal cord. The disease is estimated to affect two people in every 100,000, including about 30,000 Americans and 3,000 Canadians, many of whom have trouble walking, talking and eating.
Michael Swash, a neurologist from Barts and the London School of Medicine and Dentistry in London, said it was time to close the door on lithium.
"The problem with a disease like ALS is that everyone wants to treat it and people are grasping at straws," he said. Swash was not linked to the research and authored an accompanying commentary in Lancet Neurology.
He said specialized care and nutrition worked better than current drugs and could extend ALS patients' lives by a couple of years.
Scientists don't completely understand the cause of ALS, and Swash said more research is needed on how it evolves.
"The chance of finding a treatment without understanding the disease is very small," he said.
Britain's Motor Neurone Association is funding another lithium study. They insisted the drug might still be worthwhile.
"To stop our U.K. trial at this stage would throw away the real possibility that lithium might still have a significant benefit," Brian Dickie, the association's director of research development, said in a statement.