New cases of PML in Tysabri users

Dublin: The latest safety update on the Tysabri multiple sclerosis (MS) drug — co-owned by Elan and US pharma Biogen Idec — has found nine new cases of PML, the potentially fatal brain disease and possible side effect of using the drug, in patients.

There have now been 59 cases of PML, among Tysabri users in Europe, 46 in the US and six in the rest of the world.

Some 20% of those patients have died from the disease.

While the number of PML cases has risen this year, this is likely to reflect the general rise in Tysabri user numbers. Elan, which earlier this week upped its full-year earnings guidance after a strong first quarter to the year, is hopeful of doubling its share of the MS treatment market to around 20%, by the introduction in the next few years of tests aimed at improving the drug’s safety and better predicting the potential for individual patients contracting PML.