The Food and Drug Administration sent health-care professionals an alert Thursday about a Wyeth (WYE) kidney-transplant drug that discussed a possible increased risk of death.

The FDA said Wyeth submitted clinical trial data involving Rapamune "that suggested that there may be increased mortality in patients converted from calcineurin inhibitor therapy to [Rapamune]." The study involved use of the drug in liver-transplant patients.

The drug is only approved for use in kidney-transplant patients. The agency said "the safety and efficacy of this drug in liver or lung transplant patients have not been established."

The FDA said it is determining whether a labeling change is needed. Rapamune already carries the agency's toughest boxed-warning, which includes langauge cautioning against use of the drug in liver patients.

-By Jennifer Corbett Dooren, Dow Jones Newswires; 202-862-9294; jennifer.corbett@dowjones.com