The FDA is huddling with Biogen Idec and Elan on amendments to Tysabri's label. The reason, of course, is the news of two cases of the brain disorder progressive multifocal leukoencephalopathy, or PML, that emerged in late July.
In a notice on the agency's website, the FDA reiterated its belief that Tysabri taken on its own may generate a smaller risk of PML than when it's taken in combo with other meds that alter the immune system.
Compared with the response the last time PML emerged in Tysabri patients, it's mild. As you know, Tysabri was pulled from the market when PML first cropped up, but was allowed back on the market on a strict risk-management program, under which patients using the drug are monitored for infection. Investors showed their relief by pushing Biogen shares up by about 2 percent to $53.48, and Elan shares by 5 percent, to $14.25.