( and the knowledge of thelong-term safe...)Data Presented at the American Academy of Neurology's Annual,Meeting Provide Update on Utilization and Safety of Tysabri in,Patients with Multiple Sclerosis,Health

The combination of TOUCH, TYGRIS and the pregnancy registry will be the largest long-term follow-up undertaken for an MS therapy, and the companies plan to continue to provide similar updates at upcoming medical meetings.

The companies recently announced that as of mid-April, approximately 12,500 patients have been prescribed TYSABRI worldwide. In both commercial use and clinical trials, there are currently over 10,000 patients on TYSABRI therapy worldwide.

-- In the US, approximately 6,600 patients are on TYSABRI therapy commercially. Approximately 10,000 patients have enrolled in the TOUCH program and 1,500 physicians have enrolled patients.

-- In the EU, approximately 2,500 patients internationally have received TYSABRI infusions commercially, mostly in Germany and the Nordic countries.

-- In clinical trial settings, over 1,000 patients are on TYSABRI therapy.

TYSABRI Efficacy Sustained through Three Years

Patients who participated in the Phase III TYSABRI program were eligible to enroll in an open-label extension study that evaluated the therapy's long-term effects. Included in this were patients from AFFIRM, a randomized, double-blind, placebo-controlled, two-year monotherapy study of TYSABRI that enrolled 942 patients (627 patients on TYSABRI, 315 on placebo). In AFFIRM, TYSABRI reduced the annualized relapse rate in patients with MS by 67% (p<0.001) and the risk of 12-week sustained disability progression by 42% (p<0.001) compared with placebo.

In the intent to treat analysis, the annualized relapse rate for patients treated with TYSABRI over the three-year period was 0.23, translating into an average of one relapse every 4.3 years. The relapse rate also continued to remain low over the three-year treatment period with TYSABRI: 0.27 during the first year; 0.20 during the second year; and 0.15 during the third year (based on 531 patien
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