The Neurological Devices Panel met on May 14, 2009 at the Gaithersburg Holiday Inn located at 2 Montgomery Village Avenue, Gaithersburg, Maryland. The Panel met in order to provide recommendations on the approvability of Confluent Surgical Inc.’s Premarket Approval (PMA) application, P080013, the DuraSeal Xact™ Sealant System. The device was proposed for use as an adjunct to sutured dural repair to obtain watertight closure during spinal surgery.
The sponsor’s and FDA’s presentations covered the product description, including discussion of the hydrogel chemistry, the preclinical biocompatibility and animal modeling evaluations, as well as the clinical protocol study design and study’s findings. Both presentations, with respect to the preclinical information, noted that the device had been adequately defined and evaluated. The formulation of the device was noted to be identical to that of the sponsor’s previously approved dural sealant product indicated for use as an adjunct to sutured dural repair during cranial surgery to provide watertight closure. The sponsor’s presenters and the FDA review team found that the device had clearly met the protocol-specified primary effectiveness endpoint in attaining superiority against control, standard-of-care, treatments in achieving an intra-operative watertight, assisted closure of the dura. However, the issue of whether the intra-operative surrogate endpoint served as an adequate indicator of device performance was raised by the finding that at 3 months follow-up, patients in the two cohorts had equivalent rates of cerebrospinal fluid (CSF) leakage. In addition, while not statistically significant, the number of serious adverse events observed in the treatment arm, were noted to be higher than in the control group.
The Panel voted 4-0 to recommend to FDA that the sponsor’s application be found approvable with 3 conditions of approval. The panelists were somewhat divided over the adequacy of the intraoperative CSF leak endpoint, and a consensus did believe that a more meaningful assessment of CSF leak prevention would be the 3 month, longer term assessment. However, they did believe the device acted immediately to prevent CSF leakage during closure of dural incisions, and also believed that the device would be of benefit to surgeons when used in difficult-to-surgically close, operative procedures. The panelists recommended that the product labeling contain a precaution or warning statement regarding concern over using the material in areas where compression forces may be an issue, and they recommended that the label also inform users of the 3 month CSF leak data and instruct them to surgically close the dura, when using the device, in standard surgical fashion. The Panel recommended a third condition of approval that the sponsor conduct a Post-approval Study (PAS) to investigate the estimated rates of CSF leakage, infection and serious adverse events associated with use of the device with comparison to a control cohort as determined by FDA. The Panel did not believe the PAS should be designed to include a pivotal study-type of hypothesis but thought that comparison to known leak, infection and adverse event rates, in some manner, was necessary to be able to interpret the findings at the end of the study.