Safety Board OKs Continuation of Phase 3 Trial of PXT3003 as a Charcot-Marie-Tooth Treatment

A safety review board has recommended that regulators allow Pharnext to continue conducting its Phase 3 clinical trial of PXT3003 as a treatment for the neurodegenerative disease Charcot-Marie-Tooth type 1A (CMT1A).

It was the second safety evaluation that the Independent Data Safety Monitoring Board had completed. The therapy passed the first one as well.

Pharnext has a unique approach to treatment development. It creates combinations of repositioned drugs at lower, optimal doses. It contends that the combinations, which it calls pleodrugs, are more effective and safer.

One of its pleodrugs is PXT3003, a low-dose combination of baclofen, naltrexone, and D-sorbitol for CMT1A. Patients take the oral solution twice a day.

PXT3003 has multiple mechanisms of action. To start with, it reduces excessive production of the faulty PMP22 protein associated with CMT. It also help protect nerves and improves muscle and neuromuscular  symptoms.

Positive Phase 2 clinical trial results led to both the U.S. Food and Drug Administration and the European Medicines Agency giving PXT3003 orphan drug status.

Pharnext started the Phase 3 PLEO-CMT trial (NCT02579759) in December 2015. It has enrolled 323 adults with mild to moderate CMT1A in Europe, the United States and Canada.

Over the course of 15 months, the study will compare the effectiveness and safety of two orally administered doses of PXT3003 a day and a placebo.

The primary measure of effectiveness will be whether the therapy improves patients’ disability at 12 and 15 months. The yardstick that researchers will use will be changes in patients’ neuropathy limitation scale scores.

Secondary measures of effectiveness will include muscle function tests, the time it takes a patient to walk 10 meters, changes in patients’ health-related quality of life, and adverse events.

“This second positive recommendation from an independent board of experts reinforces PXT3003’s safety profile, even in patients who received up to 15 months of treatment,” Dr. Daniel Cohen, Pharnext’s CEO, said in a press release.

“This Phase 3 clinical trial is highly significant for patients suffering from CMT1A, where only supportive care is available today,” he said. “We believe that our pleodrug PXT3003, if successful, has the potential to transform the treatment of CMT1A in adults. We look forward to completing this clinical trial and sharing top-line results in mid-2018.”