* Researchers in study had financial ties-FDA staff
* No statistical evidence money led to bias-FDA staff
* Advisory panel to weigh wider use of Dynesys device
* Zimmer shares unchanged in after-hours trade (Adds details from FDA summary paragraph 3)
By Lisa Richwine
WASHINGTON, Nov 2 (Reuters) - U.S. reviewers have raised the possibility of bias in the evaluation of a spine device made by Zimmer Holdings Inc ZMH.N, saying a majority of patients in a study were treated by researchers with a financial interest in the company.
In documents released on Monday, Food and Drug Administration reviewers said there was “a trend which suggests the possibility of bias from compensation” when payments or stock holdings were analyzed for any influence in the study of a proposed new use for the Dynesys Spinal System.
One analysis found a positive correlation between payments to doctors and success rates for the device. However, the FDA staff said the results were “far from being statistically significant” — meaning the results could have been due to chance.
The Dynesys system is already approved as an addition to spinal fusion for treating lower back and leg pain. Zimmer is seeking FDA clearance to market the device for use without fusion. The product employs screws and cables to help keep the spine stable.
The FDA reviewers said they would ask an advisory panel that meets on Wednesday if Zimmer’s application provided reasonable assurance the proposed new use was safe and effective. The panel’s input is key as the agency usually approves applications that win support from advisory panels.
Ten out of 26 research sites reported a total compensation from the company exceeding $100,000, the FDA staff said. Nearly 54 percent of Dynesys patients, and 54 percent who received fusion in a comparison group, were treated at those 10 sites.
Zimmer had no immediate comment on the financial compensation issue.
Shares of Zimmer rose 20 cents in regular trading on Monday to $52.77 on the New York Stock Exchange, and were unchanged in after-hours trading.
The FDA reviewers said Zimmer’s study showed a 52 percent success rate for Dynesys compared with 40 percent for fusion patients. Success was defined as a reduction in leg pain, a lack of major complications and improvements in other measurements.
No difference was seen in rates of device-related or surgery-related complications, FDA reviewers said. There were, however, 10 additional surgeries in Dynesys patients after the 24-four month original study period, compared with one in the fusion group, the FDA reviewers said.
In a separate summary, also released by the FDA on Monday, Zimmer said its data “clearly demonstrate the safety and effectiveness” of the device for treating symptoms such as leg pain and muscle weakness caused by problems in the lower back.
The FDA posted the staff analysis here. (Reporting by Lisa Richwine; Editing by Tim Dobbyn and Carol Bishopric)