FDA Issues Guidances on Trial Designs for Rhinitis, Anthrax Drugs

The FDA is providing additional information on trial designs for sponsors developing therapies to treat allergic and nonallergic rhinitis and anthrax exposure.

For both seasonal allergic rhinitis and perennial allergic rhinitis, at least two Phase 3 trials are needed to support either indication, the agency recommends in draft guidances released last week.

An appropriate primary efficacy endpoint is the change from baseline in the reflective total nasal symptom for the whole treatment period — two weeks for seasonal allergic rhinitis and four weeks for perennial allergic rhinitis — according to the guidance.

The anthrax guidance notes that drugs developed for prophylaxis of inhalational anthrax would be considered under the animal rule, as it would be unethical to expose healthy human subjects. Definitive human efficacy studies, therefore, cannot be conducted. The data must meet special criteria, including the endpoint being clearly related to increasing survival.