Tysabri has been linked to its first U.S. case of an often-deadly brain infection since it was re-introduced to the domestic market two years ago. Cambridge, MA-based Biogen Idec (NASDAQ: BIIB) and its partner Elan said today they have notified regulators that a rare brain infection called PML has been diagnosed in a patient with multiple sclerosis, according to a regulatory filing.
The patient, a woman, has a history of taking other immune-suppressing drugs for MS, including beta-interferons, and methotrexate for a rheumatology condition, Biogen said. The infection was diagnosed early based on a doctor’s observation of possible symptoms, an MRI scan, and an examination of spinal fluid. The patient, who had taken 14 infusions of Tysabri over a little more than a year, is being treated by her physician, said company spokeswoman Naomi Aoki.
Tysabri is under intense scrutiny for its link to PML, since it was pulled off the market in February 2005 after doctors discovered two cases of the rare infection, which can be deadly. The FDA allowed Tysabri back to the U.S. market in July 2006 after deciding that the benefit of the drug-the most effective yet against MS-was worth the risk. The drug was brought back under a strict patient monitoring program called TOUCH. No new cases of the infection had been reported until this past July, when Biogen and Elan disclosed that two patients in Europe had been diagnosed. Since then, the first patient, who was described as remaining able to walk and live at home, has “continued to improve,” Aoki says. The second patient who was hospitalized remains in the hospital, but has also made improvement, Aoki says.
More than 35,000 patients worldwide were taking Tysabri as of the end of September, so three cases is well within the warning in the drug’s label that the chances of getting PML are about 1 case in 1,000. Two analysts who sent me their notes, Christopher Raymond of Robert W. Baird and Christopher James of Rodman & Renshaw, didn’t seem alarmed by the new case. Raymond said he still expects Tysabri to generate $1.6 billion in annual sales in 2011.
“Although the headline of a new PML case is never good for the stock, given the slowdown in patient additions highlighted by management on its third quarter conference call, we believe physicians may already be reacting to this reality,” of new PML cases, Raymond said.