Thoratec has received approval from the US Food and Drug Administration (FDA) for full expansion of the HeartMate III US clinical trial.

The approval allows the company to enroll up to 1,028 patients in the trial at up to 60 sites.

According to the company, the approval was based on the FDA’s assessment of safety data from the first ten HeartMate III implants carried out in recent months during a limited enrollment phase at five sites.

Thoratec president and CEO Keith Grossman said: "We are very pleased to reach this most recent milestone with our HeartMate III clinical program, along with the increasing enthusiasm for our latest product advancements.

"Building on our recent success with rapid enrollment in the HeartMate III CE Mark study, we look forward to bringing this differentiated technology to 60 of the most active implanting centers throughout the US."

HeartMate III is a centrifugal-flow chronic left ventricular assist system that uses magnetically levitated technology foundation to reduce adverse event rates and enhance the ease of surgical placement through a compact size.

The HeartMate III US trial is a randomized non-inferiority study that compares HeartMate III with HeartMate II, including a primary endpoint of survival free of device replacement and debilitating stroke.

The firm completed enrollment of the HeartMate III CE Mark study in late 2014, and is expecting a commercial approval and launch in European markets during late 2015.

Thoratec produces products, including HeartMate II LVAS (Left Ventricular Assist Systems), Thoratec VAD (Ventricular Assist Device), as well as CentriMag, PediMag/PediVAS product lines.