Biogen stock slips after FDA approves first biosimilar to Tysabri MS treatment

Biogen Inc.
BIIB,
-0.90%
shares slipped in the extended session Thursday after the Food and Drug Administration granted a soon-to-be Novartis AG
NVS,
-1.94%
spinoff approval for the first biosimilar treatment of multiple sclerosis. The FDA granted approval to Sandoz Inc. for Tyruko, or natalizumab-sztn, the first biosimilar to Biogen’s Tysabri, or natalizumab, to treat adults with relapsing forms of MS, and adult patients with moderately to severely active Crohn’s Disease. Biosimilars are to branded biologics the way generic drugs are to branded drugs except the FDA regulates the two classes in different ways. Last week, Novartis said that it plans to spin off generics and biosimilars business Sandoz in October. On Wednesday, CVS Health Corp.
CVS,
+0.14%
said it will launch a new unit named Cordavis to work with Sandoz to produce a biosimilar to AbbVie Inc.’s
ABBV,
-0.31%
Humira. The FDA first granted approval to Biogen and Elan Corp. to market Tysabri as a treatment for MS back in 2004. In its July earnings report, Biogen reported U.S. Tysabri sales of $259.9 million, accounting for 32.4% of its U.S. product revenue in the June-ending quarter, down from $291.9 million in the year-ago period. Biogen shares dipped 0.5% after hours, following a 0.9% decline to close the regular session at $262.43.