Astellas Pharma US, Inc. v. Food and Drug Administration

In 1994, the Food and Drug Administration (FDA) approved a New Drug Application for an immunosuppressant drug, tacrolimus, which was manufactured and marketed by Astellas Pharma US, Inc. (Astellas) under the brand name Prograf. Prograf was used by liver, kidney, and heart transplant patients to prevent rejection. Prograf was characterized as a narrow therapeutic index drug (NTI), which meant small changes in the concentration of the drug in the body could lead to significant differences in pharmacodynamic and clinical response. Astellas also maintained that Prograf was a critical-dose drug, so that small changes in the concentration of the drug in the body could lead to acute rejection, toxicities, or even death, requiring careful monitoring of a patient’s blood levels. In 2007, Astellas submitted a citizens petition to the FDA requesting enhanced bioequivalent testing and warning labeling requirements for generic tacrolimus regarding transplant patients. In 2009, the FDA denied the petition and on the same day approved an Abbreviated New Drug Application (ANDA) for a generic version of tacrolimus submitted by Sandoz, a leading manufacturer of generic drugs. Thereafter, Sandoz marketed its generic version of tacrolimus in the United States, and Astellas sought a temporary restraining order and preliminary injunction challenging the FDA’s approval of the ANDA for generic tacrolimus. Astellas alleged that the FDA acted in an arbitrary and capricious manner in denying the citizen petition and approving Sandoz’s ANDA without requiring additional bioequivalency studies and that the public interest required such additional studies. The FDA defended its actions on the grounds that Astellas’s demand for additional testing was based on conjecture and was not supported by scientific literature.