FDA is seeking to clarify language in Orphan drug regulations and propose areas of minor improvement, according to a proposed rule issued Wednesday. The changes are intended to eliminate sponsors' confusion, which is evident in that 124 (38%) of 324 requests for Orphan drug designation in 2010 were denied or stayed so that the sponsor could submit additional material to respond to deficiencies.
The rule clarifies that a compound under development for a subset of a non-rare disease will not be considered for Orphan designation unless the company demonstrates that the compound would not be appropriate for use in the broader population of patients with the non-rare disease. The agency said 24% (79) of requests for Orphan drug designation in 2010 were denied or stayed because they did not identify a medically plausible subset of a non-rare disease.
The rule also clarifies that a compound could receive multiple Orphan drug exclusivities for multiple subsets of the same underlying Orphan disease, and that a drug approved for any indication could still receive Orphan drug designation for an unapproved use. The rule proposes that FDA may consider a designation request to be voluntarily withdrawn if the sponsor does not respond to a deficiency letter within one year, but the agency anticipates granting extension requests for sponsors who need to develop data supporting a designation request for a subset of a non-rare disease. Comments on the proposed rule are due by Jan. 17, 2012