Shares of Teva Pharmaceuticals, which makes the branded version of Copaxone, fell by 11% on Wednesdsay, while Mylan, which makes the new generic version, was up as much as 18%.
"Mylan has invested tens of millions of dollars over many years to bring this important medicine to market," Mylan CEO Heather Bresch said in a statement.
"Providing patients, healthcare providers and caregivers with treatment options is very important when it comes to selecting the right therapy for relapsing forms of multiple sclerosis."
MS is a disease of the central nervous system that damages the material that surrounds your nerve cells, which are cells responsible for transmitting signals around the body. Cutting off those signals can lead to symptoms like muscle weakness, trouble with coordination, and problems with memory.
Copaxone is an injected drug, which makes it a bit more complicated to make than a standard generic pill. It's considered a "complex generic drug" by FDA Commissioner Scott Gottlieb. On Tuesday, the FDA came out with new guidance for these complex generic drugs to introduce more competition and help drive prices down.
"In some cases, costly, branded drugs that are complex drugs have lost their exclusivity, but are subject to no generic competition," Gottlieb said in a blog post. "The new policies we're announcing today are aimed at ensuring that we provide as much scientific and regulatory clarity as possible with respect to complex generic drugs."
This is the first time Copaxone will face generic competition.
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