FDA'S PRK STUDY GUIDANCE FOLLOWUP REQUIREMENT FOR PHASE IIA
This article was originally published in The Gray Sheet
FDA'S PRK STUDY GUIDANCE FOLLOWUP REQUIREMENT FOR PHASE IIA would be lengthened under a proposal presented by FDA at a Feb. 26 panel meeting. Dennis McCarthy, director of the diagnostic and surgical devices branch of FDA's ophthalmic devices division, told the panel that FDA is considering extending the Phase IIa study followup periods in its draft clinical guidance for trials of photorefractive keratectomy devices to as long as 12 months. A draft of the guidance issued in January 1992 required minimum followup of six months. Other protocol modifications being considered by the agency include expanding the patient population for Phase IIb studies; the draft currently mandates the evaluation of 125 patients at five sites. In addition, FDA is thinking about requiring that all safety concerns be ruled out during Phase I feasibility studies. The panel commented on FDA's proposals but did not make any formal recommendations. Panel member Doyle Stulting, MD, PhD, Emory University, Atlanta, stated that "it's reasonable to eliminate the major safety problems" during Phase I. However, he did not agree with all of FDA's planned changes for the Phase II studies. He said that it would be appropriate to "increase the number of patients in" Phase IIa as well as Phase IIb; however, he added that it would be counterproductive to lengthen the followup time. Stulting suggested instead that FDA "shorten the [followup] time intervals so that the technology could evolve a little bit more rapidly....As long as you're reasonably sure that this is not a very dangerous technology," a shorter followup period "allows the company to move along with their studies." FDA asked the panel to comment on several other possible changes to the guidance, including adding a requirement that sponsors of PRK trials compare their safety and efficacy data with that of spectacles and contact lenses. Panel member Michael Harris, OD, JD, University of California at Berkeley School of Optometry, said that "spectacles and contact lenses could give you a good baseline to use for comparison." Several other members agreed that such data should be gathered. For example, Stulting said that "in the labeling we are going to have to have the alternatives, so the data will have to be incorporated" into the studies. Among the other issues addressed by the panel were whether substudies of the use of steroids as treatment after PRK surgery should be required and whether the scope of the guidelines should be expanded to include phototherapeutic keratectomy. Panel members did not object to adding PTK requirements to the guidance, but suggested that separate study standards should be developed for this procedure. Testing of steroids by sponsors was not advocated.
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