Heart attack cell therapy MultiStem is well tolerated when administered to damaged regions of the heart following acute myocardial infarction, according to the results of a Phase I clinical trial.

Angiotech Pharmaceuticals and their partner, Athersys, said the allogeneic cell therapy product also had meaningful impact on improving heart function in treated patients following a heart attack.

The dose escalation study assessed the safety and maximum tolerated dose of a single administration of MultiStem administered to acute myocardial infarction patients.

The primary endpoints were the evaluation acute adverse events during the first 24 hours following administration, post-acute adverse events up to 30 days later, and catheter-related events.

The study found no clinically significant changes to vital signs, allergic reactions, infusion-related toxicities or clinically significant cardiac adverse events associated with MultiStem administration.

All three dose groups in the study showed improvement in mean left ventricular ejection fraction (LVEF), a measure of heart function, compared to baseline and relative to the registry group.

Among patients with more severe heart attacks, two dose groups each showed better than 25% improvement in mean LVEF over baseline at four months post-treatment.