Phase IIb study of vanoxerine shows strong safety efficacy signals for treatment of atrial fibrillation


ChanRx has announced positive safety and statistically significant efficacy data from a phase IIb study of vanoxerine (GBR-12909), a drug in development for the treatment of atrial fibrillation. The data were presented yesterday at the American Heart Association 2013 Scientific Sessions (16–20 November, Dallas, USA)

“Atrial fibrillation affects millions of patients in the US annually, causing substantial morbidity,” said Peter Kowey, professor of Medicine and Pharmacology, Jefferson School of Medicine and Lankenau Institute for Medical Research, USA. “Currently, drugs that correct this arrhythmia are inadequate and carry safety risks including life-threatening arrhythmias, long-term toxicity and liver failure. Both the patients with this condition and the physicians treating them could benefit greatly from a drug that could safely treat this arrhythmia.”

In the randomised, placebo-controlled trial, 104 patients presenting with symptomatic atrial fibrillation or atrial flutter of recent onset were assigned to one of three doses of vanoxerine or placebo. Vanoxerine was found to be well tolerated at all doses. No episodes of monomorphic or polymorphic ventricular tachycardia were seen.

Patients participating in the trial were measured for conversion from atrial fibrillation or flutter to normal sinus rhythm. Overall, there was a highly statistically significant dose-dependent increase in the conversion to normal sinus rhythm (p-value for all doses=0.0005) compared to placebo. The highest oral dose (400mg) achieved a conversion rate of 76% at eight hours and 84% within the first 24 hours, a rate approaching that of direct current cardioversion. Patients taking placebo achieved a 25% conversion rate at eight hours and a 38% conversion rate at 24 hours.

“Not only has vanoxerine demonstrated very promising safety data, it has statistically significant efficacy signals overall and in the two highest doses tested,” said Howard Dittrich, chief medical officer for ChanRx. “The efficacy data, coupled with a remarkable safety profile in this phase II study, bodes well for the next phase of vanoxerine’s clinical development.”