An FDA advisory panel voted 6-1 that Stryker’s PMA for its OP-1 Putty for uninstrumented posterolateral fusion for the treatment of lumbar spondylolisthesis was “not approvable.” Stryker was seeking this approval based on 24 months of clinical outcome data and 36 month CT scan and reoperation rates. The CT scan and reoperation data was gathered via an extension study to the company’s original PMA.
There was a general consensus going into the meeting that the trial results made the likelihood of OP-1’s approval very low. Stryker has been struggling with the product’s approval since submitting the PMA application to the FDA back in 2006, at which point the clinical data was not supportive of product approval and the FDA required additional studies.
The FDA panel cited numerous issues with the data presented, including:
* The study results presented by Stryker were based on post-hoc analysis, a “flag” the group could not get past. In addition, the panelists cited biases within the study design as well as the introduction of type I errors (false positives).
* The clinicians argued that the presence of bone is not equivalent to bridging bone and the stabilization seen could have resulted from fibrous tissue formation.
* The patients selected for the study were a “stiff” patient population to start.
* There are unanswered questions related to immunologic effects of the protein.