BRISTOL-MYERS SQUIBB POLYURETHANE-COATED BREAST IMPLANT STUDY

BRISTOL-MYERS SQUIBB POLYURETHANE-COATED BREAST IMPLANT STUDY finds trace amounts of 2,4 toluene diamine (TDA) in the urine of approximately 75% of 61 women who received the company's implants. TDA, a known animal carcinogen and mutagen, was found in "extremely small amounts," in the "parts per trillion" range, BMS says in a Sept. 25 press release. According to FDA, the study results show a direct correlation between the level of TDA detected in urine and the time elapsed since the devices were implanted. BMS submitted preliminary results from the study to FDA in mid-August. The data was generated in the first phase of a 122-patient postmarket surveillance study, begun in July 1992, to determine the levels of "free" TDA in the urine, blood and breast milk of women with PU-foam covered breast implants ("The Gray Sheet" July 8, 1991, p. 5). In addition to the 61 women with implants, the study included 61 control patients without breast implants. The study has not found any TDA in the plasma of study subjects. BMS discontinued the breast milk segment due to lack of patient availability, according to FDA. BMS says that "trace" quantities of TDA were detected in the urine of "a few" women in the control group. This data suggests that there are "environmental sources" of TDA exposure, the company maintains. The postmarket surveillance study was mandated by FDA in June 1991, a few months after BMS' former subsidiary Surgitek, the largest manufacturer of polyurethane foam-coated implants, pulled its Meme and Replicon prostheses from the market ("The Gray Sheet" July 1, 1991, p. 5). BMS made its decision to discontinue the products after FDA reported that TDA was released from degraded polyurethane foam in lab studies. BMS subsequently sold Surgitek's non-breast implant product lines to Cabot, but retains responsibility for the postmarket study. At the time it ordered the study, FDA stated that the risk of cancer from PU-coated implants appeared to be "minimal" and was probably less than the risks involved with removing the implants; however, the agency maintained that the study was necessary for determining whether polyurethane foam breaks down into TDA in the body. FDA says that the data available to date have not convinced the agency that it should change its recommendation not to explant the devices. FDA staffers met with BMS officials during the week of Sept. 27 to discuss the methodology to be used in the second phase of the postmarket study, which will measure the concentrations of "bound" TDA in the patients' urine and blood. When the study is completed, BMS will submit a final report to the agency.