PENILE INFLATABLE IMPLANT PMAs

PENILE INFLATABLE IMPLANT PMAs should include studies with five-year followup, FDA says in a draft guidance on the development of premarket approval applications for the devices. The document, which was reviewed on April 15 by the agency's gastroenterology and urology devices panel, states that studies with "five-year follow-up data are necessary in order to characterize the safety and effectiveness of the device over its expected lifetime." The agency adds, however, that "appropriately justified alternate follow-up schedules will be considered." FDA soon expects to publish its call for the penile inflatable implant PMAs ("The Gray Sheet" Jan. 11, p. 5). The devices are not among the 31 Class III devices for which the agency in January 1989 announced it would call for PMAs. However, the draft guidance notes that due to the more than 6,500 medical device reports FDA has received for the devices since 1984, the agency has made PMAs for the devices a "high priority." FDA is accepting comments on the draft guidance through May 31. In addition to discussing the necessary clinical data, the guidance document specifies other requirements for PMAs, including manufacturing data covering chemical characterization, sterilization processes and quality assurance/control. Preclinical requirements addressed include finished product chemistry, toxicological evaluation and physical, mechanical and reliability testing. Labeling needs also are outlined. The draft guidance stipulates that the PMAs "in order to provide reasonable assurance of the safety and effectiveness" of the device "should include information from well-controlled, prospective, clinical studies, with statistically justified sample size and detailed long-term follow-up." FDA noted at the panel meeting that retrospective studies could be used as part of the PMA but should not be used exclusively. According to the guidance draft, a risk assessment for the implants "should include time course presentation of clinical data demonstrating the presence or absence of device leakage, tubing bending/kinking or disconnection,...component migration, extrusion,...infection,...patient dissatisfaction leading to surgical removal, or any other device malfunction or adverse health event." To demonstrate efficacy, the studies should determine whether the device "provides adequate rigidity (as well as length/girth enhancement, if such claims are made) to the penis to permit coitus"; the "male's psychological well-being post-implantation"; "partner satisfaction with the device"; and "the enhancement of the male's ability to conceive naturally, as a result of the improved intromission provided by the implant." The guidance document also specifically addresses potential risks associated with silicone-containing penile implants. FDA believes that data are not available "to make a reasonable and fair judgment" as to "the risks of cancer and immune related connective tissue disorders posed by silicone in the human body." Therefore, the agency stipulates that it "will require long-term post-approval follow-up" for devices allowed "to continue in commercial distribution." These "clinical studies must collect long-term data on the reproductive/teratogenic effects of the device as well as the later effects on offspring." Due to preliminary clinical data indicating that anti-silicone antibodies may be biomarkers of autoimmune disease, FDA recommends that blood testing for anti-silicone antibodies be conducted for 10-to-15 years after patients have received a silicone-containing penile inflatable implant. Although the panel did not make formal recommendations to change the draft guidance, members did air opinions on the document. Issues discussed included the merits of psychological assessments in determining efficacy of the device, the feasibility of large epidemiological studies for silicone-containing penile inflatable implants and the study of implant-associated fertility increases. Mark McIntyre, director of medical affairs for American Medical Systems and an industry representative on the panel, contended that psychological evaluations and patient/partner satisfaction should not be considered in efficacy studies. He said that assessment of clinical benefit should be limited to whether the device works properly, and not "side benefits" such as improved quality of life. Panel consultant Craig Donatucci, MD, Fitzsimmons Army Medical Center, Aurora, Colorado, was among those who concurred, saying that a device should not be categorized as failing simply because it was not used by patients. Panel Chairman John Wallin, MD, Louisiana State University School of Medicine, New Orleans, Louisiana, disagreed, stating that "the psychological aspects are extremely important both to the person who gets the penile device and his partner, and I can't say that any kinds of studies can be conducted without that type of psychological testing." Wallin added: "What happens to somebody's sex life should be the focus rather than other types of well-being parameters. So I think the psychologists really need to go and find specific tests that are going to give that kind of information." Several panel members agreed, including Marsha Wolfson, MD, Veterans Administration Medical Center, Portland, Oregon, who suggested, however, that claims of partner satisfaction need not be investigated as rigorously as claims of the patient. An alternative to epidemiological studies on silicone-containing penile inflatable implant-linked autoimmune disease was offered by panel consultant Daniel Clauw, MD, Georgetown University, Washington, DC. Maintaining that the problems in designing and executing an appropriate epidemiological study probably would be "insurmountable," Clauw proposed establishing a prospective patient registry of penile implant recipients "so that we don't make the same mistakes in trying to collect data on...[other] silicone-containing devices" that were made with breast implants. Clauw argued that "you'd have to try to track those people for a number of years. . . The five year time point is useful for the other variables," but if "we're looking at any of the autoimmune diseases that may be associated with silicone, [that] occurs seven to ten years later, so we're talking about this almost certainly being in the realm of postmarketing surveillance, not being in the realm of something that would be in an original PMA application." The guidance document does not state that epidemiological studies must be conducted; it does, however, state that any epidemiological studies that are submitted "should contain enough subjects to detect a small but significant increase in one or more connective tissue diseases (especially scleroderma) that may be associated with the use of the device." Three panel members recommended that the penile inflatable implant's effect on fertility not be studied. Addressing the issue, Wallin agreed with "the proposition that the devices not be promoted as a fertility agent unless the company desires to do that specifically." No panel members spoke out in favor of requiring fertility studies if such claims are not going to be made by sponsors.