Multiple Sclerosis Related: European regulators recommend Tysabri label update

* Say risk of the brain infection remain low

* Recommend updating label to reflect two-year risk (Adds European recommendations)

BOSTON, Jan 21 (Reuters) – European regulators have identified 31 cases of a potentially deadly brain infection in patients taking Biogen Idec Inc’s (BIIB.O) multiple sclerosis drug Tysabri and recommended new measures for dealing with the risks of the drug.

The European Medicines Agency’s Committee for Medicinal Products for Human Use, or CHMP, said Thursday that the figure was based on reported cases of progressive multifocal leukoencephalopathy, or PML, through Jan. 20.

Of the 31 cases worldwide, 23 patients had been taking Tysabri for more than two years — roughly one case of PML for every 1,000 patients treated for two years. The rate is consistent with the risk noted in the drug’s prescribing label.

Biogen markets the drug with partner Elan Corp Plc (ELN.I)

The European Medicines Agency said in a statement that it recommends additional measures to better manage the risk of PML, and said the risk of developing the disease increases after two years.

However, it said the benefits of Tysabri continue to outweigh risks for patients with highly active relapsing-remitting multiple sclerosis.

The agency recommended that several measures be put in place to ensure patients and doctors are fully aware of the risks of PML.

They include updating prescribing information about the increase in the risk of PML after two years of treatment, and providing additional advice on how to manage patients who show signs of PML.

The agency also recommended that forms be signed by patients at the beginning of treatment with Tysabri, and again after two years of treatment. The new measures are designed to complement existing measures, the agency said.

The recommendations mean the drug’s prescribing information in Europe will look more like the U.S. label.

CHMP undertook its review after it had received reports of side effects of Tysabri, including 23 cases of PML reported between July 2008 and October 2009, resulting in four deaths. Fourteen cases, including one death, were reported in Europe. (Reporting by Toni Clarke, editing by Gerald E. McCormick)