Rx ANTIFUNGAL VEHICLE & MINOR FORMULATION CHANGES SHOULD REQUIRE ONE STUDY

Executive Summary

Rx ANTIFUNGAL VEHICLE & MINOR FORMULATION CHANGES SHOULD REQUIRE ONE STUDY to support the safety and efficacy of the product, FDA's Dermatologic Drugs Advisory Cmte. recommended at its May 14 meeting. Noting that two controlled studies showing safety and effectiveness are now required for approval of a new antifungal, FDA had asked the cmte. how much data should be required for a new vehicle and for minor changes in the original formulation. Cmte. member Lowell Goldsmith, MD, University of Rochester, asserted that in the case of a new vehicle "there's a possibility" of a "bioavailability problem." He remarked that "one small study" or even a bioavailability determination would be sufficient for approval of a new vehicle. FDA posed a series of questions to the cmte. on draft guidelines for antifungal testing. In response to a question on the usefulness of evaluating new compounds with studies using an active control, the cmte. voted 5-to-3 that a positive control study could replace one of two required vehicle control studies. An investigational antifungal could, therefore, be tested against a marketed antifungal as well as its vehicle, according to the cmte. recommendation. The agency asked the cmte. "if there were adequate data to show a drug's effectiveness in tinia corporis or tinea cruris due to T. rubrum, could one extrapolate that the drug would be effective in tinea pedia due to T. rubrum if the drug showed effectiveness in tinea pedia due to other organisms?" The cmte. unanimously responded no, that tests would be required. Additionally, the cmte. agreed that cultures and KOH mounts should be required both before the after treatment to determine presence of the fungus. The cmte. also voted 6-to-3 that a study should be disqualified if it failed to include a final evaluation two weeks after discontinuation of treatment.