Medtronic Bone Device Cancer Risk Causes Concern for FDA Reviewers

Concerns over a possible risk of cancer associated with the use of a new proposed Medtronic bone graft device, known as Amplify, could threaten its approval this week by an FDA advisory panel. 

The Amplify implant is designed to treat degenerative disc disease in the lower backs of patients, and works with a genetically engineered protein, recombinant bone morphogenetic protein-2 (rhBMP-2), to instigate new bone growth. However, the findings of clinical trials on the device’s effectiveness seem to suggest that it may be linked to an increase in cancer among recipients.

The FDA Orthopaedic and Rehabilitation Devices Advisory Panel will meet this week to decide whether to recommend Amplify for approval. The FDA will then decide in the coming months whether the device should be available in the United States. Although the regulatory agency is not required to follow the recommendations of their advisory panel, it usually does.

In an FDA report (pdf) given to the panel before the meeting, FDA officials have raised concerns about clinical trials that indicate about 5% of Amplify patients developed cancer after five years, compared to only a 1.8% cancer rate among a control group that had more traditional lower back spine surgery. However, the cancers were all different types and Medtronic says that the number is not clinically significant. The FDA is asking the panel to make its own evaluation on the importance of the numbers.

The genetically engineered protein, rhBMP-2, is also used in the Medtronic InFuse bone graft. While meant to be used to replace damaged spinal disks in the vertebrae, that treatment is often used off-label in cervical fusion surgery.

Use of the Medtronic Infuse Bone Replacement Graft during cervical fusion surgery has been associated with a high rate of serious complications involving compression of the airway and nerves. Given the close proximity of the cervical spine to the airway, a number of patients who received the bone stimulator have experienced difficulty breathing, speaking or swallowing between 2 to 14 hours after surgery, which could lead to respiratory arrest or death.

A number of Medtronic InFuse lawsuits have been filed against the company, at least one of which is a wrongful death claim. However, the protein, known as BMP in InFuse, is used in a very different manner in the Amplify implant.

Medtronic’s spinal implant division brought in $3.5 billion for the company last year. Analysts expect the Amplify device to increase that amount by about $175 million in the first year, if approved. However, some say that the device only has about a 40% chance of approval.