A Serevent side effect information study designed to further evaluate the safety of Serevent was called off after an interim analysis showed more life-threatening asthma drug side effects and asthma-related deaths in patients taking the drug than those taking a placebo.

Serevent Side Effects Statistically Significant Among African Americans

The study was begun in 1996 after the Food and Drug Administration (FDA) received reports of several asthma deaths associated with use of the drug. Preliminary data showed a small, statistically insignificant number of adverse events in relation to use of the drug, however, among African Americans taking Serevent the number or adverse events, including deaths, was statistically significant.

Further, according to national treatment guidelines, asthma sufferers should take Serevent along with an inhaled corticosteroid daily. Preliminary study data showed that patients who were not taking inhaled corticosteroids at the study's start seemed to have greater risk for serious asthma drug side effects than those who were taking inhaled corticosteroids.

Though the study's data was inconclusive, the adverse events were enough to cause researchers to question why the events were happening, and the study wasn't designed to determine that. About 26,000 people had participated in the study so far, though the study was intended to enroll 60,000 patients.

The FDA plans to meet with Serevent's manufactuer, GlaxoSmithKline (GSK), to obtain more detailed data and determine what further steps should be taken. Among the FDA's top priorities is to evaluate whether certain patients may be at an increased risk for serious adverse events due to Serevent use. The FDA approved Serevent in 1994 to treat asthma and later for use in the treatment of chronic obstructive pulmonary disease.

However, the FDA stressed that patients should not stop taking Serevent without discussing it with their doctors. Based on the available evidence, they say that the benefits of Serevent outweigh the risks of adverse events.

About 20 million people suffer from asthma in the United States, and an estimated 1.3 million take Serevent. The asthma drug is one of GSK's major sellers with worldwide sales of $929 million--$549 million in the United States--in 2002. Analysts did not expect the cancelled study to greatly influence the company's economic standing.