The Sept. 4, 2015, at-risk launch of Sandoz Inc.’s Zarxio as the first biosimilar to hit the U.S. market came several months after the FDA had approved the filgrastim biosimilar due to a court battle over the requirements of the 2010 Biologics Price Competition and Innovation Act, which laid out the rules of the road for the new class of follow-on drugs. Ten years later, biosimilar developers are still struggling with some of those rules that were drafted by Congress in an effort to balance competition with innovation in the biologics space. Insulin biosimilars may be the hardest hit.