February 17, 2005

Biogen/Elan: MS drug achieves two-year primary endpoint - After two years, medicine shows 42% reduction in disease progression and low side effects.

Tysabri, a once-a-month drug, was approved by U.S. regulators last November and is seen as key for both U.S.-based Biogen (Research) and Ireland's Elan

The companies' so-called AFFIRM monotherapy trial showed a 42 percent reduction in the risk of disability progression compared to a placebo.

Importantly, the drug also demonstrated a 67 percent reduction in the rate of clinical relapses over two years, which was consistent with the one-year results.

Jack Gorman - said sustaining the relapse rate reduction over two years was impressive and a positive surprise.

It was also encouraging that adverse side effects remained modest after two years of treatment, he added.

"The results are very good," Gorman wrote in a research note. "This will help convince neurologists that the product is safe and effective over a longer time period, and will underpin revenue forecasts.

Tysabri, formerly called Antegren, is the first kind of drug to prevent inflamed cells from escaping into the tissue of the brain, where they can cause unpredictable neurological problems.

It is also the first drug for MS given once a month intravenously, versus more frequent injections.