DOXYLAMINE AND LIDOCAINE ADVISORY COMMITTEE RULINGS
This article was originally published in The Tan Sheet
DOXYLAMINE AND LIDOCAINE ADVISORY COMMITTEE RULINGS could serve as precedents for FDA in dealing with animal carcinogenicity issues, Nonprescription Drug Manufacturers Association staff members suggested at the association's annual research and scientific conference in Washington, D.C. on Nov. 18. Participating in a group presentation outlining NDMA's activities over the previous year, NDMA Pharmacology/Toxicology Scientific Associate Patrice Wright suggested that the advisory committee recommendations on doxylamine and lidocaine "should be carried agency-wide to other OTC issues." Wright noted that in the case of lidocaine, NDMA was able to successfully demonstrate that "suggestive animal bioassay data of little known relevance to human OTC use does not belong on the OTC label." FDA's Anesthetic and Life Support Advisory Committee concluded Aug. 23 that lidocaine rodent carcinogenicity studies do not show a link to cancer in humans ("The Tan Sheet" Aug. 30, p. 10). NDMA Pharmacology/Toxicology Director Lorna Totman, PhD, held up doxylamine as another "issue that stands out by way of general principle." FDA's Nonprescription Drugs Advisory Committee resolved at a meeting in late June that a doxylamine tumorigenicity label warning is not warranted based on the animal data available and given the limitations of such a consumer warning ("The Tan Sheet" July 5, p. 5). Regarding NDAC's doxylamine decision, Totman said NDMA was "able to convey the importance of framing scientific questions before the advisory committee in the context of long-standing FDA regulatory policy." NDMA is currently involved in a similar animal carcinogenicity issue with the OTC anti-acne ingredient benzoyl peroxide. In response to FDA's 1991 request for more data on the ingredient's potential tumorigenicity, NDMA has begun animal studies and recently reported to the agency that 13-week rat/mouse oncogenicity studies are expected to begin by the end of the year ("The Tan Sheet" Nov. 15, p. 7). FDA downgraded the ingredient from Category I (safe and effective) to Category III (data insufficient to permit classification) in August 1991 after studies showed that benzoyl peroxide promotes tumors in rats. FDA plans to propose a warning statement citing the animal studies. The NDMA staff also questioned the appropriateness of revisiting the safety and efficacy of monograph ingredients in light of evolving scientific standards. While acknowledging FDA's "need to send out a call for data from industry to address new significant questions from an old ingredient" previously determined to be safe and effective, NDMA Scientific Affairs Committee Chairman and Schering-Plough Senior VP-Scientific and Regulatory Affairs John Clayton, PhD, said NDMA "clearly" has "concerns when this might be taken to the point of suggesting all Category I ingredients should be reconsidered in the light of a nominal 1993 standard." He suggested that this "runs counter to the intent of established regulations" and would "amount to throwing out the OTC review." "What we would hope is that we can work cooperatively to develop the needed data to respond to a real problem, and that we are given the time needed to provide the data through appropriately designed clinical or epidemiologic trials or animal studies," Clayton explained. NDMA Senior VP-Science and Technology William Soller, PhD, noted that despite NDAC's successes over the past year, "we can all do a better job." In the "spirit of cooperative interaction," Soller recommended that the agency adopt the Institute of Medicine's December 1992 recommendations on FDA advisory committees. FDA has established working groups that are considering ways to implement the IoM recommendations.
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