The results of a phase 2 clinical trial of the drug dexpramimpexole, utilized as a treatment for neurodegenerative disease amyotrophic lateral sclerosis (ALS), suggest that the drug reduces mortality and slows disease progression. 

Researchers explain that the mortality of the disease varies widely in ALS patients, some surviving for decades and others succumbing to the disease just a year after diagnosis. This, researchers say, makes it challenging to, over a brief period of time, develop phase 2 trials which require the ability to test dosage levels and determine potential effectiveness in a small pool of participants. Researchers report that they utilized a two-stage study to combat this challenge. 

The first phase encompassed 102 recently diagnosed ALS patients. Patients were reportedly organized into four groups that received oral tablets of the placebo or dexpramipexole. Researchers say participants received a 50-150-, or 300-mg dose for 12 weeks. Following completion, researchers report that participants received the placebo for 4 weeks and then were split into two different groups. These participants were given either a 50- or 300-mg dose of dexpramipexole for 24 weeks. The study’s results indicated that the drug appeared to slow progression of symptoms. Reportedly, the 300 mg group displayed the greatest protective effect, with a 30% decrease in symptom progression compared to the placebo group. Little to no effect was present in the 50-mg dose group, researchers say.

According to the second phase of the study, similar results were exhibited. Results suggested slower symptom progression and reduced mortality. Merit Cudkowicz, MD, director of the Massachusetts General Hospital (MGH) Neurology Clinical Trials Unit and ALS Center, headquartered in Boston, Mass, led the study and comments on its first and second phases. “Since individual participants could have been in different treatment groups in the first and second stages of the study, seeing the same dose-dependent differences at both stages gives us confidence in the data,” Cudkowicz says. 

Cudkowicz adds that in a way, the studies served as two supportive entities in one trial design and, “Confirmation of these findings in the phase 3 clinical trial, which is currently ongoing, would give us even more confidence in this study design for phase 2 testing in ALS.” He also articulates the hope that the addition of dexpramipexole to the approved treatments for ALS would provide patients a chance to stay healthier longer, slowing patients’ decline in function and increasing their survival rate.

Source: Massachusetts General Hospital