The Orthopaedic and Rehabilitation Devices Panel (the Panel) met on March 31, 2009 at the Hilton Washington DC North/Gaithersburg located at 620 Perry Parkway in Gaithersburg, Maryland. The Panel met in order to provide advice and a recommendation on the approvability of the Premarket Approval (PMA) application submitted by Stryker Biotech for OP-1 Putty (P060021). This combination product is indicated for uninstrumented posterolateral spinal fusion procedures in skeletally mature patients with grade 1 or 2 lumbar spondylolisthesis who have failed at least six months of conservative non-surgical treatment.
The sponsor and FDA presentations focused on pre-clinical testing relating to manufacturing and immunogenicity of the protein, and the clinical results comparing OP-1 Putty to an autograft control. The sponsor presented clinical results using the original and modified endpoints, while FDA presented their analysis based upon the endpoint approved in the original approved IDE protocol, as well as their concerns with the subsequent analyses of modified endpoints. Except for an analysis of a modified endpoint using data collected at least three years after the initial surgery, all other analyses showed that OP-1 Putty did not achieve non-inferiority compared to the control treatment. A significant difference between the endpoints used for the radiographic evaluation related to the use of the presence of bridging bone (radiographic definition originally approved in the IDE) versus any bone (radiographic definition contained in the modified endpoints).
The Panel voted (6-1-0) to recommend that the PMA application for OP-1 Putty be found “Not Approvable.” While acknowledging that OP-1 Putty generally appeared to be safe and potentially held promise in the future, the Panel was concerned about the changes in the study protocol, not convinced that the study results based on presence of bone instead of bridging bone demonstrated effectiveness, and had outstanding concerns relating to the immunogenicity of the product. The Panel recommended that future consideration be given to understanding the immunological response of OP-1 Putty, as well as to design of a future study, including issues of contemporary study design to incorporate instrumented fusions, expanding the study population, including CT scans from the start, and characterizing the amount of product in the bloodstream.
Contact: Ronald P. Jean, Ph.D., Executive Secretary, at 240-276-3676 or firstname.lastname@example.org.
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