On Monday, Coherus BioSciences announced that the FDA had declined to approve its biosimilar version of Amgen’s Neulasta. Neulasta is used to fight infections in cancer patients. Coherus shares fell 30 percent on the market, and Amgen’s shares saw a slight uptick. If the Coherus Neulasta biosimilar had been approved, it would have been the first biosimilar Neulasta copycat to hit the market. Currently, the drug accounts for one fifth of Amgen’s annual sales. There are other companies racing to produce a biosimilar version of the drug, and Amgen expects competition by the end of 2017.