BOSTON, April 20 (Reuters) - A sixth patient taking Biogen Idec Inc’s (BIIB.O) multiple sclerosis drug Tysabri has developed a potentially deadly brain infection since the drug was reintroduced onto the market in July 2006.
The Cambridge, Massachusetts-based biotech company announced the news late on Friday on its website, saying the case was confirmed on April 15th.
Biogen has said it does not plan to announce each new case of progressive multifocal leukoencephalopathy, or PML, except as a weekly update on its website.
Even so, the confirmation occurred a day before Biogen’s first-quarter earnings conference call, and some analysts questioned why the company did not mention it.
“While we applaud management’s decision to update PML cases weekly, we think it’s fair to ponder why this wasn’t fully discussed on the earnings call,” said Christopher Raymond, an analyst at Robert W. Baird, in a research note.
A spokeswoman for Biogen was not immediately available for comment.
Sales of Tysabri, Biogen’s most important potential growth driver, have been curtailed by concerns over PML. The drug was temporarily withdrawn from the market in 2005 before being returned with stricter safety warnings.
Biogen insists physicians are becoming more comfortable with the risk of PML, but sales of Tysabri in the first quarter were $227 million, less than the $246 million analysts had expected.
“While Biogen continues its clinical/commercial initiatives to drive Tysabri utilization, sales uptick from physicians’ improved confidence on Tysabri...has yet to be seen,” said Eun Yan, an analyst at Jefferies & Company, in a research report.
Biogen sells Tysabri in partnership with Elan Corp Plc ELN.I of Ireland.
Biogen’s shares closed on Friday at $50.09 on Nasdaq. (Reporting by Toni Clarke, editing by Dave Zimmerman)