US FDA staff question Pfizer lung drug data
* Boehringer, Pfizer seek new claim for Spiriva
* FDA notes statistical issues, safety concerns
* Boehringer says drug not linked with more deaths (Corrects to show deaths higher with new formulation of drug compared with placebo in three studies)
By Lisa Richwine
WASHINGTON, Nov 17 (Reuters) - U.S. reviewers will ask an advisory panel about statistical issues and safety concerns as they weigh a proposed new claim for a lung drug sold by Pfizer Inc (PFE.N) and Boehringer Ingelheim, documents released on Tuesday said.
The companies are asking the Food and Drug Administration for permission to claim the drug Spiriva reduces flare-ups of chronic obstructive pulmonary disease (COPD).
Spiriva is currently considered the gold standard treatment for COPD, or "smoker's lung," commonly caused by cigarette smoke and other harmful fumes and characterized by a persistent obstruction of airflow in the lungs which results in breathlessness.
It is approved for treating COPD but not specifically for reducing flare-ups, a claim made by GlaxoSmithKline's (GSK.L) competing drug Advair.
FDA reviewers, in an analysis prepared for an outside advisory committee, said in two Boehringer studies of Spiriva "there are statistical issues with consideration of an exacerbation claim, which may preclude a single trial from supporting the claim."
The agency also said it will ask the panel at a meeting on Thursday to consider recent safety concerns surrounding the possibility of strokes, cardiovascular-related deaths and heart attacks with Spiriva, a daily inhaled medicine.
Boehringer, in a summary also released by the FDA on Tuesday, said findings from two clinical trials backed the proposed new claim and "updated safety data provides substantial evidence that (Spiriva) is not associated with an increased risk for fatal events or cardiovascular morbidity including stroke."
A team of researchers reported in September 2008 that Spiriva raised the risk of heart attack, stroke and death from heart disease. In the documents released on Tuesday, the FDA's drug safety unit said available data suggesting an increased risk was "not compelling."
FDA staff noted, however, that three clinical trials of a new formulation called Spiriva Respimat showed there were more deaths with that version of the drug than with a placebo. The agency said there was "no obvious pattern" that could explain the difference.
That formulation is under FDA review for approval and already is sold in Europe, said Dr. Steven Kesten, a Boehringer vice president.
Kesten said researchers who had raised concerns about the currently marketed version of Spiriva, known as Spiriva HandiHaler, did not have access to all the most recent data and the level of detail available to the company.
"When we look at that, we certainly see no association with an increased risk for any of these events," Kesten said in an interview.
In October 2008 the FDA said preliminary data from one of Boehringer's studies showed no increased stroke risk from Spiriva.
Pfizer shares closed flat at $17.94 on the New York Stock Exchange. (Reporting by Lisa Richwine; Editing by Dave Zimmerman, Steve Orlofsky and Carol Bishopric)
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