This excerpt taken from the ELN 20-F filed Mar 30, 2006.
Evaluating Tysabri in Rheumatoid Arthritis
In February 2004, in collaboration with Biogen Idec, we filed an Investigational New Drug (IND) application with the FDA for Tysabri for the treatment of RA and initiated a Phase 2 clinical trial in May 2004 to evaluate Tysabri in patients with RA. It was a multi-center, double-blind, placebo-controlled study of the efficacy and
tolerability of intravenous Tysabri in patients with moderate-to-severe RA receiving concomitant treatment with methotrexate.
This study was prematurely discontinued in February 2005 due to the voluntary suspension of Tysabri dosing in all clinical trials. The available results from the discontinued trial demonstrated biological activity, but less than competitive efficacy results. For this reason, we and Biogen Idec have decided not to pursue the development of Tysabri for the treatment of RA at this time.