The controversy surrounding recombinant bone morphogenetic protein-2 (rhBMP-2), the synthetic bone growth material used in Medtronic's "Infuse" graft product, has been "a cautionary tale" for the surgical industry, remarks spine surgeon Christopher M. Bono, MD, in the June issue of The Spine Journal, which is dedicated solely to discussion of the research and promotion of rhBMP-2.

In the issue, a group of spine surgeons allege that the authors of early studies of the material, which is frequently used as an alternative to bone grafts in spinal fusion surgery, promoted its benefits while minimizing and even omitting mention of its risks.

These early studies, funded in part by Medtronic, glossed over adverse events stemming from Infuse's use, they argue. But more recent patient studies have linked the product to such side effects as inflammation, infection, osteolysis, male sterility and even cancer, in numbers that have led the Food and Drug Administration to require listing these complications on the product's label.

"The spine care field is currently at a precarious intersection of professionalism, morality and public safety," writes Dr. Bono, chief of spine services at Brigham & Women's Hospital in Boston. "As physicians and journal editors, we felt an obligation to present a thorough examination of this controversial issue."

In a statement posted on Medtronic's website, Omar Ishrak, chairman and chief executive officer for the Minneapolis-based medical device manufacturer, stands by Infuse's safety and its benefits for patients with bone healing impairments.

"While the Spine Journal articles raise questions about researchers' conclusions in their published peer-reviewed literature," he says, "the articles do not raise questions about the data Medtronic submitted to the FDA in the approval process or the information available to physicians today through the instructions for use brochure attached to each product sold." Mr. Ishrak maintains that the company kept a vigilant eye on financial conflicts of interest with physicians.

In its coverage of the controversy, the New York Times notes that Medtronic officials admit to reviewing pre-publication studies of their products, but deny any interference with the presentation of data. "Several researchers who were involved in the Medtronic-sponsored studies have defended their reports as scientifically sound and free of company influence, either directly or indirectly," the Times writes.

Earlier this month, 2 powerful U.S. senators launched a formal investigation into Infuse and Medtronic's financial ties to physicians who conducted clinical studies of the product. For background on the ongoing controversy, read OSM's previous coverage of the Senate investigation here.

David Bernard