FDA’s Obstetrics and Gynecology Device panel recommends second-generation mini-slings to treat stress urinary incontinence be subject to 510(k) pre-market clinical trial requirements and additional post-market data collection mandates.

During a Sept. 9 meeting, the advisory panel concluded that data supporting safety and effectiveness of first-generation suburethral synthetic mesh slings was stronger than second-generation, single-incision mini-slings, which are placed through the vagina to treat stress urinary incontinence (SUI), associated with involuntary urine leakage.

Manufacturers of suburethral mesh slings, which are class II devices, include Johnson & Johnson/Ethicon, C.R. Bard, Boston Scientific and EndoPharmacueticals/American Medical Systems.

FDA convened the panel to consider the evidence on slings for stress urinary incontinence to inform the agency’s oversight of the products. FDA recently conducted a review of adverse events and the literature for the products in conjunction with a similar data review for transvaginal mesh devices for treating pelvic organ prolapse.

“The midurethral retropubic or transobturator slings are probably among the best studied procedures in gynecology” – Cleveland Clinic’s Matthew Barber

Stress urinary incontinence slings did not show the same concerning safety signals that the agency observed for mesh prolapse procedures, FDA and the panel agreed. On the previous day of the two-day meeting, the panel urged FDA to reclassify transvaginal mesh products to the highest-risk class III category and require PMAs. (See “ Also see "FDA Panel: Transvaginal Mesh For Prolapse Should Be Class III" - Medtech Insight, 12 September, 2011. ” – “The Gray Sheet” Sept. 12, 2011.)

The same level of scrutiny is not required for SUI sling products, the panel determined. But due to a gap in data between older sling designs and the more recently introduced mini-slings, more study requirements within the class II special controls system are warranted for the newer products, the advisors said.

Urogynecological surgeons at the meeting emphasized the differences between the safety profiles of the two types of transvaginal mesh devices.

“One of the most important things that hopefully will come from the panel is a clear distinction between slings and transvaginal mesh products,” said Matthew Barber, president-elect of the American Urogynecologic Society and professor of surgery at Cleveland Clinic, in an interview following the meeting.

In contrast to transvaginal mesh for prolapse, which is newer to the market, “the midurethral retropubic or transobturator slings are probably among the best studied procedures in gynecology and certainly the best studied procedure within the sub-specialty of urogynecology," he said.

Safety Of First- Vs. Second-Generation Slings

FDA’s recent literature review focused on the first generation mesh slings, which include retropubic and transobturator mesh slings that received 510(k) clearance through the late 1990s and early 2000s. The agency found those devices were as effective as surgery without mesh to treat incontinence and the main adverse events that can occur over the long term, such as erosion, infection and urinary problems.

FDA affirmed that these first-generation slings are well studied, with over 800 published studies, and said that additional pre-market and post-market studies were not necessary.

The panel agreed, concluding that unless there was a significant material change or change in the surgical access in new devices, pre-market clinical trials were not necessary. The advisors also suggested that rare adverse events could be identified using existing large-scale health databases.

In contrast, FDA and the panel questioned the safety and efficacy of the second-generation mini-slings, which have significantly less published data supporting their use.

The mini-slings first appeared on the market in the mid-2000s, and offer a smaller and less invasive treatment for incontinence than the earlier slings. (See box.)

FDA said that mini-slings are associated with greater intraoperative blood loss and higher rates of vaginal mesh erosion compared to first-generation slings.

The 510(k) pre-market trials for new mini-slings should either be randomized control studies comparing mini-sling devices to a retropubic or transobturator sling, or cohort studies, panel members said.

The advisors also called for Section 522 post-market surveillance study orders for currently marketed mini-slings. These studies should be randomized against a retropubic or transobturator sling, or include a rigorous cohort design with three to five years of patient follow-up.

Industry’s Current Post-Market Studies

But industry representatives at the meeting stressed that manufacturers were already involved in several ongoing post-market studies for single-incision mini-slings, including company sponsored studies and investigator-initiated studies.

For instance, American Medical Systems says it is conducting a post-market study of its MiniArc device, following 186 patients for up to two years, and is supporting investigator-initiated randomized control trials that are completing enrollment in Europe and Australia.

Ethicon said it is partially funding five investigator-initiated post-market studies for its Gynecare TVT Secur mini-sling.

Studies are also underway for C.R. Bard’s Adjust and Boston Scientific’s Solyx , said Piet Hinoul, director of medical affairs at Ethicon, who spoke on behalf of an AdvaMed-led industry working group at the meeting.

Sergio Gadaleta, VP of regulatory affairs at Becton Dickinson and the industry representative on the advisory panel, argued that FDA should not move too quickly to impose post-market surveillance orders while studies are already proceeding.

“I think the most appropriate approach is to see what these data provide, and then if the data that come out of these studies don’t address the questions that you all have, then to require Section 522,” Gadaleta said.

Cleveland Clinic’s Barber said he expects the forthcoming data from the current post-market studies to address many of FDA’s safety concerns with the mini-slings.

“I think within the next year or so, a lot of post-marketing questions that FDA had may be satisfied,” he said. “There’s going to be more data very soon on them. There’s nothing ever wrong with more data.”

By Rebecca Kern

FDA Panel Calls For More Studies Of Mini-Slings For Urinary Incontinence

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