My last entry described the facts leading to Amgen’s suit against FDA over denial of pediatric exclusivity for Sensipar. Below I describe what’s at issue in the case. At bottom, this litigation relates to a federal agency developing a new standard (a new interpretation of its statute) that it will apply when ruling on applications for a benefit, after its prior interpretation suffered a defeat in federal court. Rather than announcing the standard publicly, the plaintiff in this case argues, the agency applied the standard in non-public rulings for more than a decade. Not only does the standard conflict with the statute, plaintiff adds, but the agency has not been consistent in its application of the standard. Thus the dispute is more about how a federal agency is operating than it is about the law of pediatric exclusivity.