Avandia withdrawals increase and accelerate; TNS report

From July through September of this year, nearly 70% of changes in the prescribing of UK-headquartered drug giant GlaxoSmithKline's antidiabetic product Avandia (rosiglitazone) were the result of withdrawals - physicians switching patients to another therapy, according to new research from TNS Healthcare's DiabetesDynamics USA. In addition, the rate of withdrawals is accelerating, with as many in the third quarter alone as in the first and second quarters combined, it notes.

"Avandia prescribing has always been dynamic, with our research showing that, during the first half of 2007, 20% of physician consultations resulted in some kind of therapy change," noted Philip O'Hagan, international client services director for TNS Healthcare. "From January through June, 84% of those prescribing changes were positive - physicians starting new patients on Avandia, adding it to existing regimens or switching patients to Avandia from other therapies. From July forward, however, we see a dramatic turnaround, with the majority of Avandia changes now coming from doctors taking patients off the drug," he added.

DiabetesDynamics confirms that one of the main reasons physicians are switching patients from Avandia is reports that the drug is linked with increased cardiovascular risks. Indeed, GSK itself reported a 38% fall in third-quarter revenues from the drug, and a 48% plunge in US sales compared with the like, 2006 period (Marketletters October 29). During the first half of 2007, there were no cases of switching due to cardiac problems, though there were the first rumblings that publicity about side effects was beginning to have an effect. During the third quarter of the year, however, there was a massive change, with cardiac problems now the reason for 20% of Avandia withdrawals, the report points out.