Long-awaited Yale study raises questions about integrity of previous studies of Medtronic's Infuse.

  • Article by: JAMES WALSH , Star Tribune
  • Updated: June 18, 2013 - 5:45 AM

Independent researchers looking into Medtronic’s spine fusion product found that claims of its effectiveness were overblown.


Medtronic's InFuse device used in spinal surgery.

For years, spine surgeons praised Medtronic’s Infuse in helping to speed healing and reduce pain after spinal fusion surgeries, saying it was better than alternatives. Turns out, they were wrong, according to a review by Yale University.

Medtronic Inc., the world’s largest device maker, commissioned Yale researchers to oversee two independent reviews of its spinal fusion product after spine experts and U.S. lawmakers charged that Medtronic-sponsored studies had overstated benefits and downplayed the product’s risks.

To blunt such criticism, Medtronic offered complete access to its data and paid $2.5 million to have Yale lead an independent review of its spinal product, called Infuse. Yale contracted with researchers at the University of York in England and at Oregon Health and Science University (OHSU) to conduct independent studies. Both concluded in a report published Monday in the journal Annals of Internal Medicine that there is little to no difference in effectiveness between Infuse and an older method for spurring bone growth.

“The review also found ‘substantial evidence of reporting bias’ in the previous studies on the product,” officials at Oregon Health and Science University said in a statement. “The review found that Medtronic-sponsored publications analyzed or reported results in biased ways to indicate that it was more effective.”

Medtronic said Monday that the analyses confirm what the company has long claimed — that Infuse is a safe and effective product for patients, though it emphasized that it poses some risks that must be considered by patients and physicians.

“We recognize that our products and therapies must have the public and medical community’s trust, and so we will continue to create, test and explore new ways to make our clinical research available,” Medtronic CEO Omar Ishrak said in a statement.

The FDA approved Infuse spinal fusion in 2002 for use in the lower back and it has been used on more than 1 million patients. The approach involves the removal of a degenerated disc and the fusing of adjacent vertebrae to improve stability. Since its introduction, sales of Infuse quickly soared, reaching nearly $1 billion a year before falling to $528 million, according to the most recent company report.

What remains to be seen is whether the Yale project’s findings will further erode Infuse sales.

Findings and ramifications

In fusion surgeries, doctors have typically used graft material taken from the patient’s hip — called an iliac crest bone graft — to promote bone growth and improve stability.

Infuse uses recombinant human bone morphogenetic protein-2 (rhBMP-2), a genetically engineered protein, to stimulate bone growth instead. The bioengineered material is inserted into a thimble-like cage between the vertebrae.

The York and OHSU studies both determined that Infuse did not show significantly different results from the use of a hip graft. OHSU researchers concluded that Infuse has “no proven clinical advantage,” while York researchers found Infuse increased fusion rates, reduced pain by “a clinically insignificant amount and increases early post-surgical pain.” There may also be an increased risk of cancer associated with Infuse, although the risk was deemed very low.

Officials at the Spine Journal released a statement Monday, calling the Yale study the “latest shock” involving Infuse.

“The take-home message from this debacle … is that the public needs better safeguards against conflicted and tainted medical research,” said Dr. Eugene Carragee, editor-in-chief of the Journal.

He added: “At present, Medtronic-sponsored surgeons may have to finally retire the line that ‘this product is completely safe, don’t worry about it,’ but I would not count on it.”

Chris O’Connell, Medtronic executive vice president and president of its restorative therapies group, said the company will continue to invest in Infuse and that the Yale results are consistent with Medtronic’s original studies — studies that led to FDA approval of the product.

There remains an advantage to using Infuse, he said — the advantage of not having to do the second surgery to take bone from the hip. That often leads to more pain and longer recovery for patients, he said.

When asked what type of impact the Yale study could have on sales, O’Connell said he expects it to create a discourse among physicians “so they can use their expertise in the real world and apply it. Our belief is that this will generate a very balanced view.”

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