Protecting the public from faulty targeting of medicines, while preserving the crucial distinction between product and practice regulation, may require innovative regulatory approaches and close, ongoing involvement by the medical profession. This article explores four problem areas: validation of clinical claims for tests used in targeting therapies; developing and implementing appropriate restrictions on off-label use; promoting consistent concepts of clinical utility for use in various regulatory, reimbursement, and judicial contexts; and communication of clear information to guide clinicians in appropriate use of targeted therapeutic products. The article suggests an approach for addressing these problems by sharing regulatory activities between the Food and Drug Administration and a newly-created clinical standards board formed within the medical and scientific communities.