The chances of Pfizer's tafamidis getting approval in the USA have been hurt after staff at the Food and Drug Administration recommended against giving the green light to the treatment for patients with transthyretin familial amyloid polyneuropathy.

Documents released ahead of the FDA's Peripheral and Central Nervous System Drugs Advisory Committee meeting on May 24 claim that there is inadequate evidence to approve the drug, developed by Pfizer subsidiary FoldRx, for TTR-FAP. The latter is a progressive and fatal neurodegenerative disease that affects some 8,000 patients worldwide (including about 2,500 Americans) and tafamidis was approved by the European Commission last November, with the brand name Vyndaqel.

However the FDA seems less than impressed with the data package presented and one staffer has recommended outright that a complete response letter for tafamidis should be issued, an unusual step. The objection is based on the fact that Pfizer has presented just one single controlled trial and staffers said "we are very interested to hear the Committee’s thoughts on whether or not this study provides the sort of robust data that would ordinarily be required" to support approval".

Pfizer believes the data it has provided for tafamidis "provide substantial evidence of effectiveness and meaningful therapeutic benefit where there is a high unmet medical need".