Pfizer received a refusal to file letter from the FDA for tafamidis, a treatment for transthyretin familial amyloid polyneuropathy (TTR-FAP). The agency determined that the application, which was submitted in February, was not sufficiently complete to permit a substantive review. The company says that the additional information needed to support this filing is available without further clinical studies.
Pfizer obtained tafamidis when it acquired FoldRx Pharmaceuticals in June 2010. The firm specializes in drugs to treat diseases caused by protein misfolding including orphan diseases and CNS diseases.
Tafamidis was FoldRx’ lead clinical candidate. It reportedly stabilizes the protein transthyretin (TTR) and prevents dissociation of the tetramer, the rate-limiting step in TTR-FAP. FoldRx completed an international Phase II/III study in 128 patients.
Tafamidis is also being developed for cardiomyopathy. FoldRx also has research- and preclinical-stage candidates for cystic fibrosis, Huntington disease, and Parkinson disease.