Barriers to clinical translation with diagnostic drugs.

Radioactive imaging agents, like diagnostic drugs generally, undergo a drug development process that parallels that of therapeutic agents, with similar development times but substantially lower development costs and substantially smaller postapproval markets. Although rapid advances in genetic and expression profiling are furthering the development of expensive pharmacotherapies targeted to small patient populations, the commercial development of imaging agents for small patient populations is blocked by the limited revenues available with current per-dose pricing and the relatively small numbers of imaging procedures that would be performed. A wide-ranging discussion on the best approaches to allow new diagnostic imaging agents to become part of the health-care system, and benefit the patient, is needed.