The Senate Finance Committee is investigating whether Medtronic and physicians with "substantial financial ties" to the company were aware of complications associated with the company's Infuse bone graft product and failed to report them in published clinical trials.

In a letter requesting a host of documents from the medical device manufacturer, Senate Finance Committee Chairman Max Baucus (D-Mont.) and Senior Member Charles Grassley (R-Iowa) write that they are "extremely troubled by press reports" suggesting that in its own funded clinical trials, Medtronic and its paid consultant physicians may have "unreported or under-reported" potential risks associated with the use of Infuse, a recombinant human bone morphogenetic protein 2 (rhBMP-2) treatment used in spinal fusion surgery. The product is used to stimulate bone growth and, by Medtronic's estimates, has been used in more than 500,000 patients.

Despite its widespread use, Infuse has come under scrutiny for alleged off-label use and accusations of falsified research funded by Medtronic.

Several independent studies have identified risks ranging from sterility in men to "life-threatening complications," such as neurological impairment and swelling in the neck and throat.

The senators have given Medtronic until July 11, 2011, to provide "all documents and communications pertaining to adverse post-operative events and/or medical complications relating to the use of" rhBMP-2 treatments, as well as details of all payments made to clinical investigators of the Infuse bone graft. They warn Medtronic not to destroy or modify any of the requested documents.

In an e-mailed statement, Medtronic spokeswoman Marybeth Thorsgaard said the company has received and will respond to the senators' request. She also noted that the FDA-approved product labeling for Infuse warns users of several of the complications listed in the letter. "Medtronic provides PMA clinical study adverse event data to the FDA irrespective of any financial relationship between the company and the clinical investigator or study author," adds Ms. Thorsgaard.

Another statement on the company's website specifically addresses the allegations that Medtronic has not disclosed the risk of sterility associated with Infuse.

For more background on the controversy surrounding Infuse, see this report from the Milwaukee Journal Sentinel and MedPage Today.

Irene Tsikitas