No one knows exactly. We had a Neuro speak to our support group the other night. Was unsure how he felt about Tysabri before he came. He is with a MS clinic. He said by July 2006 it should be back. That would put it about right considering the FDA asked for an extension until June 2006. He had 10 patients on it. ALL had good results. That was quite encouraging. One had questionable reaction. An no, it was not PML type. Just did not tolerate it, but also did not tolerate other medicines either.