FIBER THERAPY "IRREGULARITY" CLAIM REQUIRES CLINICAL TRIALS

FIBER THERAPY "IRREGULARITY" CLAIM REQUIRES CLINICAL TRIALS to support long-term use for chronic treatment, FDA told the Nonprescription Drug Manufacturers Association in a June 11 letter. "Unless the clinical studies that support the claim for relief of occasional constipation (short-term use) could also be found adequate to support the claim for relief or avoidance of irregularity (long-term use), separate clinical trials would be needed to support this irregularity claim," OTC Drug Monograph Review Staff Director William Gilbertson explained. "Second," he added, "we are not aware of clinical studies that would adequately support a long-term indication." The FDA letter was in response to NDMA's Nov. 23, 1992 submission of a consumer research protocol aimed at supporting a statement-of-identity (SOI) claim for fiber-containing OTC laxative drug products. The proposed study is designed to obtain information on consumer understanding and physician acceptance of "fiber therapy for irregulatiry" as a statement of identity. NDMA also suggested other possible SOIs for fiber-based laxatives, such as "bulk-forming laxative" and "fiber laxative." For these terms, FDA said that clinical studies would not be required "because these terms do not imply prevention or long-term correction of disease." NDMA's proposed study would survey 200 physicians (125 general practitioners and 75 gastroenterologists) and 400 female heads of households regarding the three SOIs that would apply to fiber- based laxatives, such as Marion Merrell Dow's Citrucel, Ciba's Fiberall, Lederle's FiberCon, P&G's Metamucil, and Rhone-Poulenc Rorer's Perdiem. The purpose of the study, NDMA said, is to "assess the attitudes and perceptions of physicians and consumers in terms of the three different SOIs for OTC fiber products." FDA's response to the study protocol outlined nine reasons why the proposed study would not be sufficient to support NDMA's requested change. FDA said it is concerned whther the consumer panel will adequately represent "ordinary" consumers. FDA also argued that the study protocol "does not measure what it purports to measure, i.e., consumer understanding of certain terms related to laxatives" since it "does not provide a test of the 'best' possible terms" and because consumers often "have little knowledge of how well or poorly they understand a concept." FDA suggeted that "a more direct method" to measure consumer understanding would be to have consumers check off statements that describe how a product should or should not be used. FDA was also concerned with the "home setting" of the consumer survey and with the statistical design of the study. In addition, FDA asserted that the questions in the protocol "relate more to consumers' ability to read than on 'understanding.'" Furthermore, the agency said it did not understand the rationale behind the physician portion of the survey. "How would physicians know if consumers understand the terms being tested?" FDA asked. The Nov. 23 submission is NDMA's second research proposal regarding fiber laxative SOIs. In May 1992, NDMA sent FDA a protocol that was rejected in a July 1992 letter to the association.