After the Health and Resource Service Administration (HRSA) issued a December Advisory Opinion requiring 340B discounts for drugs dispensed through contract pharmacies, four drug manufacturers—Eli Lilly, AstraZeneca, Sanofi, and Novo Nordisk—have now filed four separate lawsuits in three jurisdictions challenging the validity of the Advisory Opinion. The lawsuits argue that the Advisory Opinion is both procedurally and substantively deficient in violation of the Administrative Procedure Act. Several of the manufacturers, and the Pharmaceutical Research and Manufacturers of America in a separate lawsuit, also have challenged HRSA’s final alternative dispute resolution rule issued in December.