The search for new drugs: a theory of R&D in the pharmaceutical industry

摘要

Purpose: The purpose of this paper is to use a dynamic model of optimal patent design and, in the presence of information externalities, to study the evolution of technological progress in the context of a pharmaceutical industry. Design/methodology/approach: A theoretical analysis approach is adopted to drive the paper’s findings. Findings: Pharmaceutical firms with an active drug discovery program behave strategically in their R&D and in the product markets. It is shown that a firm holding an earlier-expiring patent only chooses to proceed with R&D activates when the patent it holds expires if the expected discounted payoff net of R&D costs yielded by this action is positive. The expected discounted payoff net of R&D costs obtained by this firm is then decreasing in R&D costs, increasing in the cumulative quality discovered in the past R&D activates, and decreasing in the number of past R&D activities, etc. Originality/value: The preceding literature on the topic works with only one brand, the brand with the highest quality. As well, the demand is assumed to be completely inelastic. In the conventional models of patent design, the role of competitive fringe firms is discussed implicitly. The model presented in this research is a rigorous continuous in-time dynamic model. It considers several differentiated products. Furthermore, the demand for a brand is taken to be a function of income, its price, and the prices of other brands. The interaction of the fringe firm with other patent-holding firms is also explicitly considered under this framework.