The FDA finalized its 2016 guidance discussing the nonclinical evaluation of drugs intended to treat osteoporosis. The guidance provides recommendations on the design of bone quality studies in appropriate animal models that are needed to support the approval of osteoporosis drugs and biologics. It also discusses bone-specific pharmacologic and toxicologic endpoints to evaluate the effects of a drug on bone quality in the nonclinical testing. The final guidance modifies the recommended number of dose levels to be evaluated in the bone quality studies and adds a recommendation to use a multifactorial approach to determine the treatment duration in the studies, according to a notice to be published in Thursday's Federal Register.