SILICONE GEL-FILLED BREAST IMPLANT STUDY CONSENT FORM MUST TELL PATIENTS OF STUDY RESULTS LINKING SILICONE GEL WITH HEIGHTENED IMMUNE RESPONSE, FDA SAYS
This article was originally published in The Gray Sheet
Executive SummarySilicone gel-filled breast implant manufacturers must modify the informed consent form used for clinical trials of silicone gel-filled breast implant manufacturers so that it includes information on recent animal studies linking silicone gel with heightened immune response. In a March 22 "Talk Paper," FDA says that after reviewing the two rat studies, it has decided to require that silicone gel- filled breast implant manufacturers "update information about the possible connection between the implants and immune-related disorders in the informed consent documents for women receiving breast implants under clinical studies." One of the rat studies was conducted by Dow Corning ("The Gray Sheet" March 22, p. 6); the other was done by John Naim, MD, Rochester University Hospital, et al. and published in the March issue of Immunologic Investigations. FDA's order will principally affect Mentor, the only firm with full clearance to distribute silicone gel implants for clinical studies under an FDA-designed three-stage protocol ("The Gray Sheet" April 20, 1992, p. 1). McGhan has agency clearance to distribute a limited number of the silicone gel breast implants for women with the company's temporary tissue expander in place. The firm is otherwise barred from distributing the devices because it is out of compliance with good manufacturing practices. Dow Corning, which has withdrawn from the breast implant business, submitted the results of its study to FDA on March 10 and then met with the agency on March 15 to discuss the data in detail. The firm released information on the study in a March 17 statement. Dow Corning says that it undertook its study after learning about the results of Naim's trial. In the Immunologic Investigations report, Naim et al. state that their study of 60 rats demonstrates that "silicone gel is a potent immunological adjuvant." The investigators note that "the first step toward establishing whether silicone gel and/or silicone oil has the potential of inducing an auto-immune syndrome is to determine their adjuvancy potential in general." Based on the study results, Naim et al. conclude that "the probability exists that silicone gel is able to mediate an autoimmune reaction." In its Talk Paper, FDA says that the Dow Corning and Naim studies, which were similar in design, "have shown that silicone gel of the type used in breast implants can act as an antibody adjuvant -- that is, it can enhance the ability of the animals' immune systems to produce antibodies to an antigen." FDA notes that "under these test conditions, the antigen alone would not have been expected to produce an immune response. In the presence of silicone gel or another [control] adjuvant, however, it produced a strong antibody response." The agency adds that it "believes that these studies help provide a scientific understanding for the possible link between silicone gel-filled breast implants and autoimmune-like disorders." FDA comments that, although the studies "do not prove the implants cause immune-related disorders," the results are "consistent" with the agency's long-standing concern that "silicone gel might provoke an immune response in at least some women." The agency concludes: "More research will be needed before the relevance of these studies to women with breast implants can be established."
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