A Food and Drug Administration panel of medical experts said a Stryker Corp. (SYK) spinal “putty” should not be approved for use in a wider group of patients.
The panel voted 6 to 1 in recommending that the FDA not approve the product, known as OP-1 putty, which is currently on the market for use in a small group of patients for whom previous spine surgeries have failed. Most panel members said the main clinical trial comparing use of the putty to another procedure didn’t show the putty was equally as good, although many said they thought the putty was safe to use. The FDA usually follows its panels’ advice but is not required to.
In a statement, Styker said, “We are very disappointed by the FDA advisory panel’s vote.” The company said it believed the clinical evidence it had submitted and postmarketing experience with the product “demonstrate OP-1’s proven safety record.”
The FDA had raised several concerns about the product in background memos prepared for the meeting, including the manufacturing of the protein used in the product and patients’ immune responses to it.
The agency also said the main clinical study comparing OP-1 putty in patients undergoing surgery with an auotgraft showed those receiving the autograft did better.
In an autograft, bone is typically taken from a patient’s hip and used to fix damaged vertebrae in the spine. The OP-1 putty is also designed to help fuse bones together in spinal surgery.
The FDA said “control subjects had a higher rate of bone formation” compared with patients receiving the OP-1 putty.
“Based on our reviews of these data the agency has questions whether or not this combination product can be considered relatively safe and effective when compared to auotgraft control,” the agency said.
Stryker said the main study findings were driven by bone growth measured by an X-ray 24 months after the procedures. The company said while bone growth wasn’t seen on many patients in the putty group at 24 months it was seen on CT scans at nine months and suggests “that the plain film technique used to assess fusion at 24 months was flawed for assessing the medial bone formation associated with OP-1 putty.” The clinical study was designed before CT scanning was considered an acceptable standard of measurement.
The company said patients receiving the OP-1 putty had similar clinical outcomes as patients undergoing autograft spine procedures and fewer patients in the putty group had to be retreated.