In a recent decision, the U.S. Court of Appeals for the First Circuit held that Rule 23’s “predominance” requirement barred certification of a class of all indirect purchasers of a prescription drug because the class included members who were uninjured by the alleged anti-competitive activity – they were “brand loyal” and would not have purchased a cheaper generic product even were it available. Asacol makes it more difficult to certify antitrust class actions in the First Circuit and its effects may extend further if the First Circuit’s reasoning is adopted by other circuits.