FDA ortho panel rejects PMA application for spine anti-adhesion gel by 5-2 vote

In its first meeting in a year, on July 15 the FDA Orthopaedic and Rehabilitation Devices Panel voted 5-2 against recommending the premarket approval application for a spinal anti-adhesion gel intended for use in patients undergoing lumbar spine surgery.

Oxiplex S/P Gel, a tissue barrier product (FzioMed Inc., San Luis Obispo, Calif.), is approved for use in 49 countries, including Canada. It has been used in about 100,000 procedures worldwide, company officials said.

"I don't think there are enough numbers," orthopedic surgeon Edward N. Hanley, MD, said during the meeting. "There is so much variability and I think the thing got mucked up in a statistical conundrum," particularly the efficacy results, he said.

FzioMed conducted a multicenter, randomized, third-party blinded, 352-patient clinical trial between October 2002 and October 2006 looking at efficacy and safety of the gel.

According to documents submitted to the FDA, FzioMed sought approval "as a surgical adjuvant during posterior lumbar laminectomy, laminotomy, or discectomy to improve patient outcomes by reducing postoperative leg pain, back pain and neurological symptoms." They proposed the gel be applied by syringe to exposed exiting nerve roots and along the dura at the end of surgery, prior to closing soft tissue incisions.

In the clinical trials, patients undergoing procedures at L4-5 through L5-S1 were randomized to receive the gel during surgery or to a control group who did not receive it. Investigators followed them 6 months postoperatively using the Lumbar Spine Outcomes Questionnaire to assess outcomes and satisfaction.

While the pivotal study showed the gel was reasonably safe, with only one patient in the Oxiplex group requiring a reoperation and no adverse events, panelists concluded the study suffered from unconvincing efficacy data. For example, improvement was seen in leg pain in the Oxiplex group but it "was not amenable to statistical testing by univariate methods," the sponsor's executive summary noted.

Furthermore, statistically significant improvements related to efficacy endpoints seemed to occur mainly in subpopulations rather than the overall group. Panelist Stuart B. Goodman, MD, PhD, of Stanford University, Stanford, Calif., noted even the sponsor expressed the overall group did not meet those endpoints, yet a subset they identified did.

Many panelists, like Hanley, of Carolinas Medical Center, Charlotte, N.C., thought the product was likely safe, but voted against approval due to serious concerns over its efficacy. "While I deep down as a spine surgeon want to approve this stuff ... I have to reject this, based upon the training and principles of the FDA process. ... I think there is a need for something like this and it may well be that in certain patients it can be helpful," Hanley said.