 That and other related litigation lasted until 1982.Often, the series of cases is referred to as the “antibiotics litigation.”

The focal point of the case was the two companies’ settlement of an interference proceeding before the PTO (the U.S. Patent and Trademark Office) over the priority of their respective applications for tetracycline.Under the settlement, American Cyanamid, which had acquired Heyden Chemicals‘s pending tetracycline application, conceded the priority of Pfizer’s application, withdrew its own application and exchanged cross licenses with Pfizer.