Pfizer’s Drug for Rare Nerve Disease Rejected by U.S. FDA

Pfizer Inc. (PFE), the world’s largest drugmaker, failed to win U.S. regulators’ approval of its drug to treat TTR-FAP, a rare and deadly genetic disorder affecting 8,000 people worldwide.

The Food and Drug Administration asked for a second clinical trial showing the effectiveness of tafamidis meglumine, New York-based Pfizer said today in a statement. The pill would be the first approved treatment in the U.S. for TTR-FAP, or Transthyretin Familial Amyloid Polyneuropathy.

TTR-FAP robs patients of the use of their limbs from the feet upwards, and as their digestive system turns against them, they waste away and die in about a decade. In Europe, the drug was approved in November for sale under the name Vyndaqel. Pfizer estimates there are 3,000 U.S. patients.

“TTR-FAP is a relentless and debilitating disease. We understand the urgent need within the patient community and stand firmly behind this innovative medicine,” Yvonne Greenstreet, senior vice president and head of medicines development group for Pfizer’s Specialty Care Business Unit, said in the company’s statement. “It is our intention to request a meeting as soon as possible with the agency in order to discuss a potential path forward.”

Tafamidis works by locking down transthyretin, a protein made by the liver. In healthy people, the protein holds together. In those with TTR-FAP, it breaks apart, forming toxic plaques that attack the body’s longest nerves, paralyzing limbs and ruining the digestive system.

Liver Transplant

The current treatment is a liver transplant -- the organ produces the problematic protein and a new one can extend patients’ lives.

Analysts haven’t estimated a market for the medicines. Pfizer declined to comment on its European or potential U.S. sales.

Alnylam Pharmaceuticals Inc. (ALNY), based in Cambridge, Massachusetts, also has a drug in early trials to treat TTR-FAP. Isis Pharmaceuticals Inc. (ISIS), based in Carlsbad, California, and London-based GlaxoSmithKline Plc have teamed to develop a treatment.

The Alnylam and Isis drugs stop production of the transthyretin protein, said Rodney Falk, director of Boston- based Brigham and Women’s Hospital’s program for cardiac amyloidosis, a related disease where patients’ heart muscles are damaged.

To contact the reporter on this story: Drew Armstrong in New York at darmstrong17@bloomberg.net;

To contact the editor responsible for this story: Reg Gale at rgale5@bloomberg.net

Bloomberg reserves the right to remove comments but is under no obligation to do so, or to explain individual moderation decisions.

Please enable JavaScript to view the comments powered by Disqus.