GlaxoSmithKline said today US regulators had halted clinical trials on multiple sclerosis drugs in the same class as recently withdrawn treatment Tysabri, including its experimental product '699.
Tysabri, which was developed by Elan and US-based Biogen Idec, was pulled from the market on February 28th after a patient died from a rare and often fatal infection of the central nervous system.
Both Tysabri and '699, which GSK is developing with Japan's Tanabe Seiyaku Co Ltd, work by inhibiting alpha-4 integrin, a substance implicated in the disease.
"The FDA has taken the precautionary measure of placing a clinical hold on investigational new drugs in the alpha-4 integrin antagonist class being tested on human subjects, which includes '699," a GSK spokesman said.
GSK said it was not aware of any similar problems with its drug to those experienced with Tysabri.
"Whilst '699 has the same molecular target as natalizumab (Tysabri), '699 is chemically unrelated to natalizumab," he said. GSK and Tanabe's drug is taken as a pill while Tysabri is given as a monthly infusion.
GSK had been expected to report Phase II trial results with '699 by the end of this year, ahead of an anticipated filing for regulatory approval in 2008.
The Food and Drug Administration (FDA) move will delay that timetable, although industry analysts said the impact on GSK's overall drug business would be limited since '699 is only one of 45 Phase II drugs in development at Europe's biggest drugmaker.