Spinal Tap: Medtronic Studies Are Repudiated

Spinal Tap: Medtronic Studies Are Repudiated

June 29th, 2011 // 1:09 pm @

In a highly unusual move, a medical journal has devoted an entire issue to dissecting a mushrooming controversy over Infuse, a genetically engineered protein that is made by Medtronic and has been widely used in spinal surgeries. But the Spine Journal reviewed 13 studies previously published elsewhere and discovered that side effects were downplayed or omitted.

What sort of side effects? Cancer, sterility, infections and dissolving bones. There was also leg and back pain. And these occurred between 10 to 50 times the original estimates calculated in the studies. Moreover, all 13 studies were funded by Medtronic. However, none of these side effects were reported in the papers, even though the studies were peer reviewed.

And just when you think things can’t get any worse… The authors of these papers maintained Infuse rarely caused complications and – guess what? – they also had financial ties to Medtronic worth tens of millions of dollars. The median financial association ranged from $12 million to $16 million, according to The Spine Journal, which is the official publication of the North American Spine Society and devoted its issue to the reviewing Infuse research.

We should note that the US Senate Finance Committee is currently investigating Medtronic over reports that doctors with financial ties to the device maker were aware of serious problems with Infuse, but never disclosed potential health complications in published studies. The US Department of Justice opened its own investigation three years ago.

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In reviewing the studies, The Spine Journal also found that study design appeared biased against common alternatives for spinal fusion, which could inflate the apparent benefit of the products. And the studies included invalid claims about risks and complications associated with using a patient’s own bone to assist fusion.

Six of the 13 papers were published in Spine, a publication that has no relation to The Spine Journal, while the other seven papers were published in the Journal of Spinal Disorders & Techniques; the Journal of Bone and Joint Surgery, and the Journal of Neurosurgery: Spine. But yes, The Spine Journal did publish one of the papers.

”It harms patients to have biased and corrupted research published,” five doctors, including the editor of The Spine Journal, wrote in a joint editorial called ‘Years of Living Dangerously.’ “It harms patients to have unaccountable special interests permeate medical research. It harms patients when poor publication practices become business as usual. Yet harm has been done.”

Christopher Shaffrey, an editorial board member of the Journal of Neurosurgery: Spine, tells The Wall Street Journal that the complications “should have been reported” in the papers. “This is an important article that calls attention to the need for full disclosure and full reporting” by study authors.

This latest chapter in the Infuse controversy presents a stiff challenge to Omar Ishrak, who recently joined Medtronic as ceo. In response to The Spine Journal, he issued a statement in which he says “integrity and patient safety are my highest priorities. While the Spine Journal articles raise questions about researchers’ conclusions in their published peer-reviewed literature, 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.

“Based on that data, we strongly believe that the safety profile reported to the FDA and summarized in the product label support the safe use of (Infuse) for the identified indications. We remain committed to ongoing study of the safety and efficacy of (Infuse), especially in applications not covered by FDA labeling. For several years Medtronic has been leading the industry in reforms designed to eliminate or mitigate conflicts of interest. We will continue to investigate questions surrounding researchers’ potential conflicts of interest, refine our policies as warranted, and strive to lead the industry in ethical and transparent business practices” .

Ishrak may regret some of his words. In the review, The Spine Journal found that one study that was published in 2009 in the Journal of Bone and Joint Surgery about a related Medtronic product called Amplify did mention a high probability of a link to cancer. This link occupied 15 pages of a 68-page FDA summary discussing Amplify prior to approval earlier this year, but was mentioned in the study. However, Medtronic chief scientific officer Richard Kuntz says the cancer link is not convincing.


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