An ongoing clinical trial of the asthma drug Xolair suggests that patients taking the medication may have an increased risk of blood clots, heart failure, stroke, cardiac arrhythmias and heart enlargement when compared to patients not treated with the asthma drug, the Food and Drug Administration said Thursday. The agency announced it was assessing the significance of the preliminary findings to determine if further regulatory actions are necessary to protect patients.
Omalizumab, marketed as Xolair, is approved as a treatment for adults and children older than 12 who suffer from moderate to severe asthma complicated by seasonal allergies. The concern over possible side effects has arisen out of a trial comparing 5,000 Xolair users and 2,500 asthmatics not taking Xolair over a five-year period. Xolair was approved by the FDA in 2003, and last year, brought its maker, Genentech, $517 million in revenues.
The FDA said that "interim data" provided by Genentech from that trial "suggests a disproportionate increase in ischemic heart disease, arrhythmias, cardiomyopathy, cardiac failure, pulmonary hypertension, cerebrovascular disorders, and embolic, thrombotic and thrombophlebitic events" among users of Xolair. The agency's announcement emphasized that no causal link between the drug and the adverse events has been established, and advised patients prescribed the drug not to discontinue its use at this time.
The FDA's announcement is termed an "early communication."
Unless the FDA calls a halt to the safety trial, it is expected to continue, with final results expected in 2012. The FDA in 2007 required Xolair's maker to include a "black box warning" -- the agency's highest level of consumer alert -- warning patients that Xolair may cause potentially fatal anaphylactic reactions.