A drug treatment for a rare neurodegenerative disorder won't be approved until its manufacturer comes up with new data to prove that it works, the FDA has told the company.
Pfizer said it received a "complete response letter" from the FDA regarding tafamidis meglumine (Vyndaqel) for treating transthyretin familial amyloid polyneuropathy, a genetic disorder that causes progressive and fatal nerve failure. About 8,000 people have the condition worldwide, according to the company.
The FDA told Pfizer that it should conduct a new clinical trial "to establish substantial evidence of effectiveness," the company said, adding that agency officials also want more information on the data already supplied.
Tafamidis meglumine is designed to stabilize the defective transthyretin protein so that it remains functional.
An FDA advisory committee, meeting last month, gave the drug a mixed review. It voted 13-4 that Pfizer's single randomized trial had failed to demonstrate that tafamidis slowed disease progression.
On the other hand, the panel voted by the same margin that improvements in secondary outcomes, such as lower limb function, could form the basis for approval.
The drug was approved last November in the European Union for the disorder.
Pfizer said it would "work with the FDA to address the content of the [complete response] letter" and would seek a meeting with agency staff to discuss how to proceed.