New Med Not the Answer for Lou Gehrig's

Dexpramipexole for amyotrophic lateral sclerosis not effective over placebo in study of Lou Gehrigs disease patients

(RxWiki News) A cure for Lou Gehrig's disease has yet to be discovered. As researchers explore possibilities, a new study has shown that what was thought to be a potential new medication for the condition might not be the answer. 

The study explored the safety and effectiveness of a medication called dexpramipexole in patients with Lou Gehrig's disease.

The researchers found that the patients receiving the medication fared no better in terms of symptoms or lifespan than those not receiving the medication.

"Discuss signs of muscle weakness with a health professional."

Amyotrophic lateral sclerosis (ALS), perhaps better known as Lou Gehrig's disease, is a neurological disease. According to the National Institutes of Health, the rapidly progressive condition attacks the nerve cells, called neurons, that help to control voluntary muscles like those found in the arms, legs and face. 

The authors of this new study, led by Merit E. Cudkowicz, MD, of the Neurology Clinical Research Institute at Massachusetts General Hospital in Charlestown, explained that finding ways to treat ALS has proved difficult. It is thought that since cells' mitochondria are important energy producers for neurons, medications that focus on mitochondria might help ALS patients. 

The medication tested here, dexpramipexole, is thought to improve the function of mitochondria, Dr. Cudkowicz and colleagues explained. Their study aimed to test the usefulness and safety of dexpramipexole in patients with ALS. 

This study included 942 ALS patients gathered from 81 academic medical centers in 11 different countries. These participants were between 18 and 80 years old. Their first onset of ALS symptoms started within two years of the study's beginning.

One group of participants (474 patients) received 150 milligrams of dexpramipexole twice a day, and the comparison group (468 patients) received a placebo, or inactive sugar pill, for 12 months.

To measure the outcomes, the researchers used the Combined Assessment of Function and Survival (CAFS) score. This measurement ranks outcomes based on the patient's time of death and changes to their score on the Amyotrophic Lateral Sclerosis Functional Rating Scale-revised (ALSFRS-R).

The ALSFRS-R measures the progression of symptoms in ALS patients, including speech, swallowing, handwriting and walking. The possible range of scores is 0 to 48, with a lower score representing more severe symptoms.

For CAFS, the ALSFRS-R score was combined with time of death (with an earlier time of death ranked worse and survival ranked higher) and compared to other patients. The average CAFS score for the group was then calculated, with a higher score showing a better group outcome. 

After one year, average CAFS scores did not show a significant difference between the two groups. The dexpramipexole group scored an average of 441.76 and the placebo group scored an average of 438.84.

There was also no major difference seen in the average change from the beginning ALSFRS-R score. The dexpramipexole group saw an average 13.34 point drop in scores and the placebo group saw an average 13.42 drop in scores.

No significant difference was seen in the number of deaths either — 74 (16 percent) of the dexpramipexole patients and 79 (17 percent) of the placebo patients died during the year-long period.

Most reports of side effects were similar between the two groups, including issues like constipation, nausea, weight loss, insomnia and muscular weakness. However, 37 patients (8 percent) from the dexpramipexole group developed neutropenia, a condition characterized by low levels of a type of white blood cell called neutrophils. Only eight patients (2 percent) from the placebo group developed this condition. 

"Dexpramipexole was generally well tolerated but did not differ from placebo on any prespecified efficacy endpoint measurement," wrote Dr. Cudkowicz and colleagues. "Our trial can inform the design of future clinical research strategies in amyotrophic lateral sclerosis."

The study was published in online September 23 by The Lancet Neurology. The study was designed by Biogen Idec and Knopp Biosciences and funded by Biogen Idec. Both companies produce medication for neurological conditions.

A number of the study's authors have served as consultants and board members for a variety of pharmaceutical companies including Teva Pharmaceuticals, GlaxoSmithKline, Biogen Idec and Knopp Biosciences and a number of the authors have received research funding from a variety of organizations, including National Institutes of Health and the ALS Association.

Review Date: 
October 14, 2013