Zarxio® is biosimilar to Amgen's Neupogen® (filgrastim), which was originally approved for use in 1991 to stimulate the proliferation and differentiation of white blood cells. On July 24, 2014, Sandoz announced that the FDA had accepted its Biologics License Application (BLA) for filgrastim, an application which was filed under the new biosimilar pathway created in the Biologics Price Competition and Innovation Act of 2009 (BPCIA). Amgen brought suit on October 24, 2014, alleging that Sandoz violated the terms of the BPCIA for biosimilar applicants and asserting, among other claims, California state law claims for unfair competition.