An exploratory analysis of patent fencing in pharmaceuticals: The case of PDE5 inhibitors

Firms pursue a number of strategies to appropriate value, including patenting. In this paper I study patent fencing, a specific filing strategy to use multiple related patents to further enhance value appropriation. The paper addresses the pharmaceutical industry, which shows a high patenting propensity and strong lifecycle management activities leading to additional patent filings per drug. Building on an inductive case study, this paper explores the mechanisms behind patent fencing within a novel class of drugs. Patents with offensive blocking potential are primarily filed in the a later stage of the lifecycle and are tied to certain categories of patents with a low potential to substitute prior filings economically, while filing of patents with defensive blocking potential occurs more often in the early lifecycle stage. Finally, a model is developed on patent fencing in pharmaceuticals that builds on these patents’ characteristics.