F.D.A. Asks If Faulty Blood Monitor Tainted Xarelto Approval
By KATIE THOMAS FEB. 22, 2016
The Food and Drug Administration is investigating whether a faulty blood-testing device may have compromised the results of a clinical trial that led to the approval of Xarelto, a blockbuster anticlotting drug that has been prescribed to millions of Americans since it arrived on the market in 2011.
The agency has asked the drug’s manufacturer, Johnson & Johnson, detailed questions about whether there was evidence that the device was malfunctioning while the trial was underway, according to a legal brief filed in federal court on Monday by lawyers for patients and their families who say they were injured by the drug. The lawyers also cited internal company documents that they said showed doctors were complaining to the trial leadership during the course of the study.
The clinical trial, known as Rocket AF, was led by Dr. Robert M. Califf, currently President Obama’s nominee for head of the Food and Drug Administration. It involved more than 14,000 patients worldwide and took place from 2006 to 2010.
Xarelto, which is also known by its scientific name, rivaroxaban, is one of a new class of drugs that are seen as a replacement for warfarin, a cumbersome 60-year-old drug used to prevent strokes in people with a heart-rhythm disorder known as atrial fibrillation. Warfarin requires careful monitoring of a patient’s diet and drug regimen, and frequent blood tests to ensure that is working. If patients receive too little of the drug, they could experience a stroke. But if they receive too much, their lives could be threatened by catastrophic bleeding.
Questions about the trial have been stirring since last fall, when Johnson & Johnson and Bayer, which sells Xarelto overseas, notified regulators that the device that was used in the trial had been recalled in 2014 because it was understating patients’ risk of bleeding. The device, the INRatio sold by Alere, was used in the trial to help doctors gauge whether patients were getting the right dose of warfarin. The trial compared the number of strokes and bleeding events experienced by patients taking Xarelto to those of patients who were given warfarin.
Regulators are looking at whether the malfunctioning device might have led doctors to give patients the wrong dose of warfarin, which could have led to additional bleeding episodes and given an unfair advantage to Xarelto.
This month, researchers with the Duke Clinical Research Institute, which oversaw the trial, published their own analysis in the New England Journal of Medicine and concluded that the faulty device did not affect the trial’s outcome. A few days later, an analysis by the European Medicines Agency, the F.D.A.’s European counterpart, came to the same conclusion.
But rather than settling the matter, the analyses have raised additional questions and have come under harsh criticism from some medical experts. The Duke researchers, for example, never mentioned the existence of central laboratory tests — taken at two points during the trial — that could have been used to assess whether the device’s readings were accurate. And the analysis released by the European drug agency, while it did include those readings, was done by the companies themselves and not by independent statisticians.
“There are so many questions that are yet unaddressed,” said Dr. Harlan M. Krumholz, a cardiologist and director of the Yale University Open Data Access Project, which has an agreement with Johnson & Johnson to make the company’s data from clinical trials available to outside researchers. He has asked the company for access to the trial data, he said, and the company has agreed — but Bayer has refused.
Dr. Krumholz called on Alere to release more information about its device. “We do not know why the device did not work well,” he said.
In a statement, a spokeswoman for the F.D.A. said that while the agency was looking into the issue, it had not changed its recommendations for the drug, which “provides an important health benefit when used as directed.”
A spokeswoman for Alere declined to comment, and a representative for Duke referred to an earlier statement detailing the results of its reanalysis.
Johnson & Johnson said the INRatio device was selected because it was F.D.A.-approved and easy to use. It said it was not informed of the device recall until last September, when it and Bayer “acted with urgency, diligence and in the best interests of patients and prescribers.” The company said that it has provided answers to the questions the F.D.A. asked and that the analysis published in the New England Journal of Medicine confirmed the safety and efficacy of the drug.
A spokesman for Bayer said the company was confident in the results of the trial and dismissed the issue as being driven by plaintiffs’ lawyers, saying, “They have cherry-picked testimony and documents divorced from any context.”
Dr. Califf is the former director of the Duke Clinical Research Institute, which conducted the trial, and served as the study’s co-chairman. He has since left Duke and is now a deputy commissioner of the F.D.A. Dr. Califf, who did not respond to an email, has no role in the inquiry into the Rocket AF trial, the F.D.A. has said. The Senate was expected to vote Tuesday on whether to confirm his nomination as head of the agency.
Just as the trial was getting underway in 2006, the INRatio was facing scrutiny by the F.D.A. In 2005 and 2006, the agency sent warning letters to HemoSense, then the manufacturer of INRatio, claiming that the devices were generating “clinically significant” erroneous values and that the company, which was later acquired by Alere, was not properly investigating the complaints.
In 2014, Alere recalled the INRatio monitors, saying that they might provide inaccurate results.
However, the connection to the Rocket trial was not made public until this past fall, when a journalist for the British Medical Journal began asking the companies about it. A spokesman for Johnson & Johnson told the journal that the company had been unaware of the recall. The revelation led to the reanalysis by the Duke researchers as well as inquiries by the European Medicines Agency and the F.D.A.
But while the European agency concluded that the trial outcome was not affected by problems with the device, the F.D.A. appears to be taking a closer look, asking pointed questions about whether the company had evidence that the device was malfunctioning during the trial and what actions it took, according to the legal document, which was filed with Judge Eldon E. Fallon in the Eastern District of Louisiana.
The legal motion filed on Monday also cited internal emails that, the lawyers said, showed that some doctors were questioning the accuracy of the device while the trial was underway. The lawyers said so many concerns were raised about the device that a special program was set up to investigate the malfunctions, but none of these details were provided to the F.D.A. when Johnson & Johnson responded to the agency this month.
The Rocket trial has previously come under criticism. In 2011, the F.D.A.’s medical reviewers recommended against approval of Xarelto, citing concerns that the patients receiving warfarin during the trial were being poorly managed, which could give an unfair advantage to Xarelto.
An outside advisory committee later voted to approve the drug — although several members cited reservations — and the agency allowed it to go on the market. It has since become the best-selling drug in its class, bringing in $1.9 billion in the United States in 2015, according to Johnson & Johnson.
Some said the fact that Xarelto has been on the market since 2011 gave them faith in the safety of the product. “The real world has already made the case for this drug,” said Dr. Jürgen vom Dahl, a German cardiologist who served as an investigator in the trial, who said he did not recall encountering any problems with the device.
Dr. vom Dahl also said that he and his German colleagues have wondered whether Dr. Califf’s F.D.A. nomination was playing a role in the renewed questions about the trial. “We don’t know what is real science, and what is more politics,” he said.
But others say that plenty of questions remain, and that they are disheartened by a seeming reluctance by Duke, Johnson & Johnson and Bayer to be forthright about the problem.
“It depends on where you put the flashlight,” said Robert Powell, a clinical pharmacologist who has worked in the drug industry, as well as for six years at the F.D.A. “I think they were directing people away from the problem.”
Sabrina Tavernise contributed reporting.
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