'Me-Too' Innovation in Pharmaceutical Markets.

Critics of me-too innovation often argue that follow-on drugs offer little incremental clinical value over existing pioneer products, while at the same time increasing health care costs. We examine whether consumers view follow-on and pioneer drugs as close substitutes or distinct clinical therapies. For five major classes of drugs, we find that large reductions in the price of pioneer molecules after patent expiration-which would typically lead to decreased consumption of strong substitutes-have no effect on the trend in demand for follow-on drugs. Our findings are likely unaffected by health insurance, competitive pricing of me-toos, marketing, and switching costs.