GAITHERSBURG, Maryland Advisers on Tuesday narrowly backed an experimental Medtronic Inc spine implant that uses a protein to stimulate bone growth and help relieve low-back pain.
The committee of Food and Drug Administration advisers voted 6-5 that the benefits of the Amplify device outweighed risks. Three panelists abstained.
The FDA will consider the recommendation as it decides whether to approve Amplify, which could help Medtronic boost the spine business that now accounts for 22 percent of the company's sales.
Amplify contains a genetically engineered form of a protein to help fuse vertebrae by promoting bone growth.
Medtronic said Amplify offered a safe and effective alternative to standard fusion surgery using a piece of a patient's hip bone implanted in the spine.
FDA reviewers, however, voiced concern about cancer cases seen in some patients treated with Amplify.
At five years, cancer rates were 5 percent with Amplify and 1.8 percent in the standard fusion group. Medtronic said the differences were not statistically significant, meaning they could have been due to chance, and there was no biological reason to suggest Amplify caused cancer.
Panel members were split on whether the protein in the device might contribute to cancers. They voted 9-4, with one abstention, that Medtronic provided "reasonable assurance" that Amplify was safe.
Some said their concerns were eased because the reported cancers were several different types. If the device was to blame, it is likely the cancers would be similar, they said.
"Seeing a smattering of all these different cancers ... it doesn't raise a red flag to me," said panelist Mary Kemeny, an oncologist at Queens Cancer Center in New York.
Several panel members urged more study of cancer rates after the device reaches the market.
The protein used in Amplify is called recombinant human bone morphogenetic protein-2, or rhBMP-2. It is used in Medtronic's InFuse device, which is already on the market for spinal surgery and other uses.
Morgan Stanley analyst David Lewis said the panel "failed to deliver a clear endorsement" for Amplify. Committee members "had difficulty reaching agreement on statements around Amplify's safety, particularly with regard to cancer, and efficacy data," Lewis said in a note to clients.
A delay for the product would be a "small negative" for Medtronic as InFuse already is used in the types of surgeries the company wants to target with Amplify, he added.
For Amplify, Medtronic studied 463 patients randomly chosen to receive the new device or the standard fusion procedure. After two years, 60.5 percent of Amplify procedures were judged a success compared with 55.5 percent in the control group.
The FDA panel voted 10-3 that Medtronic provided reasonable assurance the device was effective. One panelist abstained.
Medtronic argued that Amplify offered an option that avoids the extra surgery needed to remove part of the hip bone and its possible complications such as pain or infection. Company officials said they were pleased with the panel votes and would work with the FDA to address any concerns.
Dr. Susan Alpert, Medtronic's senior vice president for global regulatory affairs, said she did not hear any panel concerns "that could not be overcome."
"There are issues that can be addressed," she said.
Spinal products accounted for $3.5 billion of Medtronic's $15.8 billion in fiscal 2010 sales.
Medtronic shares closed up 1.1 percent at $37.39 the New York Stock Exchange.
(Reporting by Lisa Richwine; Editing by Gary Hill and Carol Bishopric)