Rare diseases, orphan drugs and their regulation: questions and misconceptions.

Sustained advocacy efforts driven by patients' organizations to make rare diseases a health priority have led to regulatory and economic incentives for industry to develop drugs for these diseases, known as orphan drugs. These incentives, enacted in regulations first introduced in the United States in 1983 and later in Japan, Europe and elsewhere, have resulted in substantial improvements in the treatment for patients with a range of rare diseases. However, the advent of orphan drug development has also triggered several questions, from the definition of rarity to the pricing of orphan drugs and their impact on health-care systems. This article provides an industry perspective on some of the common questions and misconceptions related to orphan drug development and its regulation, with the aim of facilitating future progress in the field.