6th Case of PML Found in Tysabri Patients
This past weekend, Biogen Idec, Inc. (BIIB) reported that another patient taking Tysabri had developed a case of progressive multifocal leukoencephalopathy, or PML.
This is the sixth case of PML since July 2008. In the most recent case, a patient being treated for multiple sclerosis on Tysabri developed the disease after 31 months. All patients are taking Tysabri as a notherapy, with the minimum therapy before noted disease of 12 months. The average length of time for the sixth patients dosing is 19 months. Five of the six reported cases were located outside the U.S.
Despite the new case of PML, Biogen Idec and Elan continue to educate and train physicians under the risk management plan (RiskMAP). This includes the recent warning on potential liver damage as well. As of the end of the first quarter, there are currently 39,900 patients on Tysabri worldwide (20,800 in the U.S, 18,500 Ex-U.S, 600 in clinical trials).
Some 25,000 patients have been on the drug over 1-year, with 14,400 patients on the drug over 18 months and 6,800 on the drug over two years. When re-approved in June 2006, Biogen, Elan, and the FDA / EMEA agreed the risk threshold for keeping the drug on the market would be 1/1000. Using the 18+ month 18,500 patient group, the current incidence rate of 6/18,500 still falls well within the acceptable range.
We continue to expect reported cases of PML over the next several quarters. Biogen has been reporting, on average, about one new case per quarter. However, given the powerful efficacy of the drug, as well as the increased education and awareness around PML, we do not believe this will be a significant deterrent to new patient growth.
Worldwide sales of Tysabri were $227 million, $116 million in the U.S. and $111 million outside the U.S., in the first quarter. Despite the most recent case of PML, we expect that Tysabri revenues will grow to $1,045 million ($536 million in the U.S. and $509 million internationally) worldwide in 2009. Full report in Zacks Investment Research
