The US Food and Drug Administration is looking into a potential link between Roche and Novartis' asthma drug Xolair and “an elevated risk of cardiovascular and cerebrovascular adverse events”.

The agency says it is evaluating interim safety findings from an ongoing study, EXCELS, which involves approximately 5,000 patients treated with Xolair (omalizumab) and a control group of some 2,500 patients not treated with the drug. The study, which was submitted to the FDA by Roche's Genentech unit, is designed to assess the long-term safety profile of Xolair in patients followed for five years.

The agency says the interim data suggest “a disproportionate increase in ischemic heart disease, arrhythmias, cardiomyopathy and cardiac failure, pulmonary hypertension, cerebrovascular disorders, and embolic, thrombotic and thrombophlebitic events" in the Xolair arm of the study. However the FDA is not recommending any changes to the prescribing information for the drug and is not advising patients to stop taking Xolair at this time.

It added that until the evaluation of the EXCELS study is completed, and the final results are expected in 2012, “healthcare providers and patients should be aware of the risks and benefits described in the prescribing information”. Genentech spokeswoman Tara Cooper said that "at this time, there is insufficient information for the companies to change their assessment of the benefit-risk profile for Xolair”.