WASHINGTON Early data from a 4-year clinical trial show no increased risk of stroke in patients given Pfizer Inc's lung drug Spiriva compared with placebo, the U.S. Food and Drug Administration said on Tuesday.
Favorable results from the trial contrast with retrospective pooled analyses of dozens of previous studies that had suggested a higher risk of stroke among patients taking the once-daily inhaled medicine.
The FDA said a clearer picture of the drug's safety will not be available until it receives and analyzes final data from the new formal study, which involved almost 6,000 patients with chronic obstructive pulmonary disease (COPD). The condition, which is highly linked to smoking, involves bronchitis and emphysema.
The FDA in March had cautioned patients and doctors about the possible complication of stroke after a company analysis of 29 clinical trials showed a greater risk in those taking the medicine.
Concern about possible risks of the drug intensified last month, when a separate analysis of pooled data from 17 international studies suggested the medicine raises the risk of heart attack, stroke and death from heart disease. The analysis was performed by independent investigators.
But results from the new 4-year trial, known as Uplift, showed no such risk for Spiriva, Pfizer and its marketing partner Boehringer Ingelheim said last month. The drugmakers sponsored the trial.
"The preliminary results of Uplift reported by Boehringer Ingelheim to the FDA showed that there was no increased risk" with Spiriva, the FDA said on Tuesday.
The agency said it expects to receive complete data from the Uplift trial next month, and it will likely take another several months to review the results and report its own interpretations of the findings.
Late in the session on a sharply lower New York Stock Exchange, Pfizer shares were off 98 cents or 5.2 percent at $17.96.
(Reporting by Susan Heavey and Ransdell Pierson in New York, editing by Gerald E. McCormick)