Piper Jaffray downgrades Elan Corp. (ELN ).
Analyst Deborah Knobelman says she is downgrading Elan to market perform from outperform.
She believes the newly diagnosed case of PML (progressive ultifocal leukoencephalopathy) in a patient on Tysabri monotherapy adds a new level of risk to the possibility of Tysabri ever returning to market. She notes this is the third reported case of PML in a patient on Tysabri monotherapy.
Knobleman says she no longer feels comfortable recommending Elan shares, even for the most risk-tolerant investor. She maintains her earnings assumptions for Elan, as she had previously removed Tysabri from her model.