Eli Lilly & Co. v. American Cyanamid Co.
United States Court of Appeals for the Federal Circuit
82 F.3d 1568 (1996)
Opos (defendant) used Lilly's (plaintiff's) patented process to manufacture Compound 6, an intermediate compound, in Italy, but subjected Compound 6 to four additional chemical-reaction steps — adding and removing hydroxyl and carboxyl groups — to produce the structurally different final antibiotic cefaclor before importing it into the United States for distribution; the district court found Lilly unlikely to succeed on its infringement claim because the intervening processing materially changed the product before importation.
Whether infringement occurs when a chemical product made using a patented process is imported into the United States if, prior to importation, the product was subjected to additional processes resulting in a final compound with substantially different properties.