HeartWare International Inc. (NSDQ:HTWR) shares continued their fall for the second straight day on concerns over the higher-than-expected rate of blood clots in a clinical trial of its mechanical heart pump.
The Framingham, Mass.-based company said Friday that a 250-patient study of its HVAD Left Ventricular Assist system showed a 9 percent thrombosis rate. Results from the Advance trial, which showed a 94 percent survival rate after 180 days, were released at the International Society of Heart and Lung Transplantation in San Diego.
Concerns over the thrombosis rate had Wall Street buzzing. Physicians interviewed by several media outlets said a 9 percent blood clot rate more than doubled their expectations for the study.
The results seem to reinforce concerns raised by analysts back in February, after a Wisconsin hospital suspended clinical trials of the device after a patient developed a blood clot that caused it to malfunction. HeartWare officials were besieged by questions during a Q4 conference call about a report by Reuters that Aurora St. Luke’s Medical Center in Milwaukee recently suspended new implants after the patient — who was also treated with a blood-thinning drug — later suffered an intra-cranial hemorrhage.
Shares of HeartWare are down nearly 15 percent since posting a closing price of $83.91 April 15.
