LONDON — European drugmaker GlaxoSmithKline PLC said yesterday it had suspended clinical trials of an experimental drug to treat multiple sclerosis and Crohn’s disease, in line with a US regulator’s ruling.

The US Food and Drug Administration this week called for a suspension of Glaxo’s SB 683-699 because it is in the same class as the recently withdrawn Tysabri multiple sclerosis medication.

The producers of Tysabri, Biogen Idec Inc. and Elan Corp., suspended sales of the medication last month after two patients undergoing long-term treatment with Tysabri and a second Biogen Idec drug, Avonex, developed rare brain infections called PML.

GlaxoSmithKline spokesman Chris Hunter-Ward said that while the Glaxo trial drug had the same molecular target — to block a substance called alpha-4 integrin — as the withdrawn Tysabri, it showed pharmacological distinctions.

Hunter-Ward said Glaxo’s drug ”belongs to a different class of agents and therefore is unrelated to Tysabri.”

He said drug studies — which had reached a second phase, with 400 participants receiving the drug — had shown no signs consistent with PML.

Results of the study were due to be reported in the final quarter of 2005.

Hunter-Ward said the disclosure was disappointing news for GlaxoSmithKline, which was developing the drug in collaboration with Japanese company Tanabe Seiyaku Co.

Code Securities analyst Paul Diggle told Dow Jones Newswires that while the suspension of drug trials was a disappointment, it would have had a greater impact if the drug had been closer to regulatory filing.

”It’s another one of those slight hurdles of some products in the pipeline,” he said, pointing out that about two-thirds of drugs in phase 2 trials don’t make it to the next development stage.

By Associated Press | March 17, 2005

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