U.S. Food and Drug Administration advisers were not persuaded by the clinical trial results on the efficacy of the drug for BioMarin Muscular Dystrophy. The drug, drisapersen, fell short in proving its effectiveness in patients suffering from Duchenne muscular dystrophy (DMD).
Duchenne muscular dystrophy causes progressive weakness and loss of muscle mass mostly seen in males. This condition is characterized by the lack dystrophin, a protein that keeps muscles and cells intact. In the long run, infants born with this condition will lose muscle mass leading to muscle degeneration and weakness.
The exact number of DMD cases is still unknown. In the latest data reported by the Centers for Disease Control and Prevention, about 15 out of every 100,000 males aged 5 to 24 years old were affected in 2007. A prevalence of about one in 3,500 boys was reported and by the time the boys reach the age of 20 or 30 years old, this condition could be fatal.
The FDA regulatory panel, instead of voting on the approval of the drug, asked its members about the strength and weakness of the presented Biomarin Trials. The result of the voting showed that 15 members said that the lack of statistical significance of the drug's late-stage clinical trial, sapped the findings of past studies. The study measured how far the patients could walk in six minutes.
BioMarin's drug, drisapersen, was developed to increase the body's production of dystrophin that can help increase muscle strength. It is an investigational antisense oligonucleotide drug candidate for the treatment of DMD.
In June, BioMarin announced that FDA accepted for review the submission of a New Drug Application for drisapersen and an advisory committee meeting to discuss the application was scheduled.
Apart from showing skepticism about the drug's effectiveness, the FDA evaluators pointed out how the phase III of the trial is not "statistically significant for its primary endpoint."
"The study diminished my conviction about the findings in studies 1 and 2, and of the post-hoc analyses or [the drug company's] potential explanations such as including patients with more advanced disease, inadequate treatment duration, expertise of various centers, or lack of a loading dose," FDA advisory committee chair Dr. Caleb Alexander from Johns Hopkins Bloomberg School of Public Health said.
"I wasn't convinced ... and [study 3] decreased my belief in the persuasiveness of the first two studies," he added.
On the other hand, one of those who voted that the phase III of the trial has no impact on the overall efficacy of the drug is the patient representative on the panel. "If a parent looked at this, they would take the possible 10-meter advantage," Cheri Gunvalson, a registered nurse and a mother of a patient. "In the face of a lethal diagnosis, it's better than what we've got," she added.
FDA will release its official decision on Dec. 27.
