Shares in US firm Corautus Genetics went into freefall yesterday after patient recruitment was suspended into a trial of a catheter-delivered drug, intended as a treatment for unstable angina.

Corautus said it was halting the study of vascular endothelial growth factor (VEGF-2), delivered using a catheter system developed by Boston Scientific, after the independent monitoring committee said the risks of the treatment outweighed its benefits. Its shares slumped 69% to close at $1.07 as a result.

Last month, Corautus said three incidents of a serious cardiac condition called pericardial effusion occurred among trial participants, and the US Food and Drug Administration promptly placed a clinical hold on the study until the monitoring committee examined the data. Pericardial effusion is an inflammation of the sack-like covering of the heart and can be life-threatening.

The company said it will continue to collect data from the Phase IIb GENASIS trial until the last patient enrolled has been followed for six months. At that time, it will lock the study database and analyse the efficacy of the VEGF-2 treatment. It is still hoping to develop VEGF-2 for peripheral artery disease and diabetic neuropathy.

Corautus had to cancel a proposed stock offering last month as a result of the clinical hold on the trial.