The decision by Medtronic, the nation’s biggest producer of heart devices, raises more questions about the safety of the St. Jude component — an electrical wire that connects an implanted defibrillator to a patient’s heart — and about how executives of that company have responded to those issues.
St. Jude executives have repeatedly insisted the wire, or “lead,” known as the Durata, is safe. Asked about the new study, which was sponsored by Medtronic, a spokeswoman for St. Jude said in a statement that numerous studies and tests had demonstrated the safety of the insulating material used in the Durata.
“We do not rely on Medtronic to confirm the safety and reliability of material we use in our products,” the statement, by Amy Jo Meyer, said.
Shares of St. Jude fell more than 12 percent Wednesday, to $31.37, after the Food and Drug Administration released a plant inspection report that found significant problems in the company’s testing and oversight of the Durata. The stock price represented a three-year low.
The F.D.A. report, which raises the prospect of potential agency action against St. Jude, appears to be the latest misstep by company executives in dealing with questions from investors and doctors about the safety of the Durata and an earlier heart device lead called the Riata, which the company has recalled.
In October, St. Jude executives released the F.D.A. report as part of a filing with the Securities and Exchange Commission but blocked all references in it to the Durata. In taking the unusual action, the company stated that it believed the F.D.A. would make similar redactions when it released the report in response to a Freedom of Information Act request, but the agency did not do so.
Earlier this year, St. Jude’s chief executive, Daniel J. Starks, also publicly criticized a heart device expert, Dr. Robert G. Hauser, after he raised questions about the safety of the Riata and the Durata. Mr. Starks then sought to have a medical journal retract an article written by Dr. Hauser. The publication refused.
“It’s becoming increasingly difficult to defend Durata,” one Wall Street analyst, Lawrence Biegelsen of Wells Fargo Securities, wrote Wednesday in a note to investors in which he downgraded St. Jude stock to hold from buy. He added that the release of the full F.D.A. report was “likely to heighten concerns” among doctors about using the Durata lead.
The Medtronic-sponsored study at issue appeared in the November issue of a scientific journal, Macromolecules, which is published by the American Chemical Society, a professional group.
In it, researchers looked at the durability of two chemically related insulating materials. One material that St. Jude calls Optim is used in the Durata. Medtronic was interested in using the other material, called Pursil 35, in a new heart device lead it was developing. Both products belong to a class of materials known as silicone-based polyurethanes.
The products were developed by different companies in an effort to solve a longstanding problem. Over time, insulating materials used in implanted devices are broken down by bodily fluids, exposing them to possible electrical failure and even short circuits that can prevent a device, like a defibrillator, from working when needed to save a life.
Recent episodes involving failures of heart devices or their components have involved failures of the insulating materials used in them.
In the study, both Optim and Pursil 35 were exposed in laboratory tests to water and heating techniques aimed to accelerate aging of the materials. While the Pursil 35 material changed faster than Optim, both materials lost substantial strength in the tests, said Dr. Frank S. Bates, a professor at the University of Minnesota and a Medtronic consultant who was involved in the study.
A spokesman for Medtronic, Christopher Garland, said the study results led the company recently to cancel the development of a new lead that would have used Pursil 35 as an insulating material. St. Jude has an exclusive arrangement with the developer of Optim to use it in heart device leads. Mr. Garland said that Medtronic had also been looking at that material’s use in other kinds of medical devices.
He added that Medtronic was working with producers of both materials to find ways to resolve some of the problems detected in the laboratory study.
Dr. James Runt, a professor at Pennsylvania State University who is a St. Jude consultant, said that the Medtronic study struck him as an “outlier” because both internal St. Jude studies and external reviews had supported the durability of Optim.
Katie Thomas contributed reporting.
Article source: http://www.nytimes.com/2012/11/22/business/new-misgivings-about-st-judes-heart-device.html?partner=rss&emc=rss