Second Circuit's Mandate Rule Limits New Causation Theories On Remand

On remand, indirect purchasers of the drug ACTOS sought to amend their antitrust complaint to modify their causal theory of harm. The district court denied plaintiffs' first set of amendments under the mandate rule, which prohibits re-litigation of issues decided by an appellate court in the same case. However, the court permitted a second set of amendments that may have the same practical effect as the first. In re Actos End-Payor Antitrust Litig., Case No. 13-9244, 2018 (S.D.N.Y., Feb. 12, 2018).

In 1999, Takeda gained US Food and Drug Administration (FDA) approval to sell the diabetes drug ACTOS, which is covered by three patents. In the FDA's Orange Book, Takeda listed its 4,687,777 patent as a drug-product patent, and its 5,965,584 and 6,329,404 patents as method-of-use patents. Takeda also allegedly made non-public statements to the FDA in 1999 and 2002 that the '584 and '404 patents were method-of-use and drug-product patents.