Can a drug once commonly used to treat schizophrenia patients also be effective in amyotrophic lateral sclerosis (ALS) patients? That is the question being investigated in a new clinical trial being led by University of Calgary’s Lawrence Korngut, MD, associate professor at the Cumming School of Medicine.
The phase 2 clinical trial plans to recruit 100 patients with ALS who will be given pimozide (4 mg/day) or placebo for up to 22 weeks. The study follows an earlier study showing antipsychotic medications can stabilize neuromuscular transmission in ALS.
ALS is a neurodegenerative disease in which a person’s ability to control their peripheral muscles progressively declines. Over the course of just a couple of years, ALS patients become paralyzed, losing the ability to walk, talk, eat, swallow, and eventually breathe.
Current treatment options for ALS patients are generally limited to improving the patient’s quality of life rather than slowing down the progression of the disease. The new study led by Dr, Korngut is designed to see if pimozine can halt the progression of the disease.
Pimozide is an older medication originally used to treat schizophrenia. It is also one of the first ‘orphan drugs’ to be approved in the United States. In 1985, it was approved to treat Tourette’s syndrome. Its antipsychotic effects are believed to be due to the drugs ability to block certain dopamine and serotonin receptors. With regard to ALS, animal studies have shown that it improves the communication process at the neuromuscular junction – the site that is deteriorating in ALS patients.
One of the major drop backs of pimozide is its severe side effects and the drug has largely been replaced by more effective, safer drugs to treat schizophrenia. Fortunately, a preliminary study led by Dr. Korngut indicates that a lower dose of pimozide may be sufficient for ALS patients. In a news report, Dr. Korngut said they did a proof-of-principle study in 25 ALS patients and it showed that a lower dose of pimozide may be useful in stabilizing ALS. In that study, they measured the functionality of the thenar muscles in ALS patients given pimozide for 6 weeks and found no decline in function. In a typical ALS patient, functional deteriortation of the thenar muscles, located in the palm of the hand, are usually one of the first signs of ALS.
In addition to the lower, safer dose being used in the study, another advantage of the drug is its cost. “Pimozide has been well known for decades as a drug approved for treating certain types of psychiatric conditions, like schizophrenia, and it only costs nine cents per pill,” says Dr. Korngut.
Eligibility criteria for the current clinical trial can be found at clinicaltrials.gov/ct2/show/NCT03272503
To learn more about ALS, visit www.als.ca