Biogen's Tysabri a Blockbuster! - Analyst Blog

Biogen Idec Inc. (BIIB) recently announced that its multiple sclerosis (MS) drug Tysabri achieved blockbuster status in 2009. Sales of the drug, which is approved for relapsing forms of MS in the US and for relapsing-remitting MS in the EU, achieved $1 billion in sales in 2009. Tysabri is marketed by Biogen in collaboration with Elan Corp. (ELN).
 
In addition to reporting Tysabri sales, Biogen provided an update on other products and pipeline candidates. The company stated that it intends to grow Avonex and Rituxan sales through lifecycle management. 

Meanwhile, Biogen recently submitted a marketing authorization application seeking approval from the European Medicines Agency for Fampridine prolonged release tablets. The company is seeking approval for the use of the candidate to improve the walking ability of adult patients with MS. Biogen is also seeking approval in Canada. Partner, Acorda Therapeutics (ACOR) has filed for approval in the US.
 
Biogen also has plans to commence a registrational trial with its recombinant Factor IX Fc fusion protein in hemophilia B patients and a phase I study with anti-LINGO-1 for MS in the first half of 2010.
 
While we are pleased to hear that Tysabri is now a blockbuster drug, we are concerned about the slowdown in the number of new patients adopting Tysabri. As of the end of December 2009, Biogen estimates that about 48,800 patients have been on commercial and clinical Tysabri therapy worldwide, up from 46,200 patients at the end of September 2009.
 
This means that approximately 2,600 new patients adopted Tysabri in the fourth quarter of 2009. The company reported 2,900 and 3,300 new patient additions in the third and second quarters of 2009, respectively. We note that the number of new patients adopting Tysabri has been declining over the past few quarters. 

We remain concerned that an increase in the number of cases of progressive multifocal leukeoencephalopathy (PML), a deadly brain infection, associated with the use of Tysabri could lead to a slowdown in Tysabri sales going forward. About 28 cases of PML infection have been reported by the company. 

We continue to expect additional cases of PML to be reported over the next several quarters. Additional instances of PML cases could hamper Tysabri's acceptance in the medical community thereby limiting its sales growth. Tysabri is the second multiple sclerosis product in Biogen’s portfolio and is a major growth driver for the company.
 
We currently have a Neutral recommendation on Biogen. Although Biogen’s core business should remain stable in the coming quarters, we believe investor focus will remain on the occurrence of additional PML cases associated with the use of Tysabri. This could remain as an overhang on Biogen's shares in the coming quarters.
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