FDA SEEKS UVA TESTING PROCEDURES FROM CTFA, NDMA
FDA SEEKS UVA TESTING PROCEDURES FROM CTFA, NDMA to be presented at an agency-sponsored workshop on UVA labeling and testing methodologies, OTC Drug Evaluation Director William Gilbertson said in May 15 letters to Cosmetic, Toiletry and Fragrance Association President Edward Kavanaugh and Nonprescription Drug Manufacturers Association President James Cope. "We believe that for the agency to propose appropriate testing procedures, the results of standardized, validated testing procedures must be submitted to the agency for review and public comment," the FDAer said. Gilbertson asked each association president to give an estimate of "how long it would take your members to come to a consensus regarding an appropriate, validated testing procedure" for UVA protection so that the agency can schedule the meeting. The OTC director said the agency is "considering having a public meeting/workshop" on UVA labeling and testing methodologies in order to expedite their inclusion in the sunscreen monograph. While the tentative final monograph is expected to be published by December, it will not address UVA I and UVA II broad spectrum protection claims or testing procedures, Gilbertson said at a recent OTC "feedback" meeting. Comments from the workshop, however, will be included in the Amended Tentative Final Monograph, which Gilbertson previously estimated would be published in approximately two years ("The Pink Sheet" May 7, T&G-7). Some industry executives have been calling on FDA to expedite the sunscreen monograph proceedings and standardize the UVA testing procedures. For example, Bristol-Myers Squibb VP-Dermatology R&D Lincoln Krochmal, MD, pointed out at a recent drug development conference in Washington, D.C. that the various "yardsticks" in the research community for measuring UVA protection "result in tremendous confusion not only for the consumer but for the recommending physician, pharmacist, and so forth." The May 14-15 conference was sponsored by International Business Communications and F-D-C Reports, Inc. Krochmal mentioned three measurements which have been developed by industry to indicate UVA protection: Bristol-Myers Squibb's "APF" UVA Protection Factor (Westwood's PreSun); Herbert Labs' "PPF" Phototoxic Protection Factor (Photoplex); and Schering-Plough's "APP" UVA Protection Percentage (Shade). The Bristol-Myers Squibb exec observed that FDA "will have to ...[allow] another number, if possible, on the sunscreens of the future. I think SPF [sun protection factor] numbers will remain, but ultimately, there will be a UVA number of some sort." He also suggested that the short, powerful UVC wavelengths, now filtered out by the ozone layer, as well as the warming infrared rays, may be a target for sunscreens in the future if the ozone layer continues to be depleted. Krochmal also discussed a number of efficacy parameters in sunscreen testing, aside from erythema, that may become preferred indicators in the future. "It is clear now...that erythema is a relevant and important parameter, but probably...it's not going to be the number one way in the future to determine if the product truly gives you benefit to your health," he predicted. "Sunburn cells," or abormal keratinocytes in the epidermis, have been discussed in the research literature as a possible "marker for premalignant changes that occur in the skin," Krochmal said. In addition, Langerhans' cells, described by the R&D exec as "the first line of defense for the immune system in determining abnormal cells in the skin," detect abnormal formations of malignant cells and trigger the immune system. Since Langerhans' cells are depleted by sun exposure, he added, "you can measure the depletion of [the cells] with and without sunscreen use just as you can measure the formation of sunburn cells with or without sunscreen use." Krochmal noted that measuring the changes in collagen and elastin in connective tissue exposed to different sunscreens can lead to understanding UVA and UVB rays' effect on skin. Further, accelerated DNA synthesis in epidermal cells or keratinocytes can indicate an attempt by the cell to repair damage by the sun, he noted.
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