The US orphan drug programme 1983-1995.

The Orphan Drug Act has become a staple of food and drug law in the US. The experience with the US programme continues to serve as a useful reference point as interest in orphan drug incentive programmes expands globally. This article first reviews details of the legislation and orphan drug regulations, and then provides a 13-year overview (1983-1995) of orphan drug activity in the US, including descriptive data on the designated and approved orphan drugs, their indications and sponsors. In light of a recent challenge to the Food and Drug Administration's (FDA's) authority under the Act, we also examine the interplay between the exclusivity provision of the Act and the orphan drug regulations that define when 2 drugs will be considered the 'same' for the purposes of the Act. A recent court decision affirming the FDA's interpretation of the clinical superiority provisions of the regulations suggests that orphan exclusivity may be less predictable and less certain than it has been in the past. Finally, we consider the usefulness to orphan drug sponsors of other initiatives such as FDA's early access and fast-track approval programmes, and the extent to which the FDA's discretion to waive, defer and reduce prescription drug user fees has worked to the benefit of orphan drug sponsors. Over the 13-year analysis period, the FDA granted 631 orphan designations involving 450 different drugs, for which 121 FDA marketing approvals have been granted. Those with both treatment investigational drug designation and fast-track approval status appeared to benefit substantially from shorter development times. The indications targeted by the orphan drugs fall into 8 categories, with 40% of all orphan indications involving cancer and genetic diseases. Evident in the latter part of the analysis period is the increasing share of orphan activity attributable to biotechnology firms. Even though the Prescription Drug User Fee Act of 1992 did not recognise orphan status for the purpose of waiving or reducing the amount of fees payable, almost one-third (32%) of the $US 8,531,550 in user fee revenue foregone through waivers and reductions was attributable to orphan drugs.