Aastrom Biosciences, a developer of autologous adult stem cell treatments for cardiovascular diseases, has temporarily suspended enrollment and patient treatment in its U.S. Phase II IMPACT-DCM clinical trial, following a report that a trial participant who received the recommended treatment died at home after being released from the hospital.

The patient's cause of death has not yet been determined and is the subject of a pending investigation at the clinical site, according to the Ann Arbor, Mich.-based company. An independent Data Safety Monitoring Board (DSMB) will also assess the circumstances of the event.

In accordance with standard operating procedures, the company said it has informed the FDA of the following: the death of the patient after being released from the hospital; the initiation of an investigation into the cause of death; and that it has voluntarily suspended patient enrollment and treatment in the trial. Subsequently, the FDA placed the trial on temporary clinical hold pending an investigation.

Aastrom reported that follow up of patients previously enrolled in the IMPACT-DCM trial will continue in accordance with study protocol.

IMPACT-DCM is a U.S. clinical trial evaluating the surgical delivery of autologous cells directly into the human heart muscle for the treatment of congestive heart failure associated with dilated cardiomyopathy in both ischemic and non-ischemic patients. The company said that patients were randomized into the treatment group of the IMPACT-DCM trial, treated with Aastrom's Cardiac Repair Cells, an autologous, mixed-cell product containing expanded populations of stem and early progenitor cells produced from a small sample of the patient's own bone marrow.