Catalyst to re-submit rare disease drug after trial success

Catalyst Pharmaceuticals is to go back to the FDA with new data from Firdapse, its treatment for ultra-rare neuromuscular disease, Lambert- Eaton myasthenic syndrome (LEMS).

The drug was rejected last February when the FDA refused to review Firdapse, saying its clinical dossier was not sufficiently complete.

Firdapse has already been on the European market for about seven years as a treatment for LEMS, but it appears the FDA has taken a much different approach to its European counterparts when it comes to approving the drug.

In Europe amifampridine-containing medicines have been used for around 20 years, and regulators were content to approve Firdapse based on previously published studies involving around 38 patients.

But the FDA has required a whole new set of clinical trial data, although it has tried to accelerate development by granting a Breakthrough Therapy designation, and helping development by providing a Special Protocol Assessment.

This resulted in a trial with two defined co-primary endpoints – a quantitative myasthenia gravis (muscle weakness) score, and subject global impression.

Results from the LMS-003 trial announced today showed that the trial of the oral medicine met both endpoints with high statistical significance.

There was also a clinically significant improvement in the muscle weakness score, which the company hopes will reassure doctors about its effectiveness when deciding whether or not to prescribe it.

The trial also met secondary endpoints of triple-timed “up and go”, and muscle weakness in limb domains. A most bothersome symptom endpoint showed a positive trend but was not statistically significant.

Patrick McEnany

After last year's failed attempt to convince the FDA with immature data Catalyst’s president and CEO, Patrick McEnany, said the company is on track to refile the drug with the FDA in the first quarter of 2018.

"We are extremely pleased with the top-line efficacy and safety results from this second phase 3 trial, which reinforces the potential of Firdapse to be an important treatment for patients suffering from LEMS. We look forward to presenting further data in future publications and at medical conferences,” he added.