In its long-awaited decision in Amarin Pharma. v. ITC, the Federal Circuit provided guidance on the U.S. International Trade Commission’s discretion to decline to institute an investigation under section 337 of the Tariff Act (19 U.S.C. § 1337) and the interplay between section 337 claims and the Food, Drug, and Cosmetics Act (FDCA) – an increasingly common issue at the ITC. The opinion also addressed the Federal Circuit’s appellate jurisdiction to review the ITC’s non-institution decisions. Companies that litigate at the ITC, particularly those that manufacture, distribute, or import FDA-regulated products, should be aware of the implications of this decision.