Cytori has shut down its ATHENA and ATHENA II clinical trials.
Cytori Therapeutics has halted the trials for its experimental stem cell therapy for heart failure. The company placed a clinical hold on its drug trial after patients began developing problems with blood flow to the brain. It is working with the FDA to resolve the issues.
Patients that are candidates for the drug would be patients who are not eligible for bypass surgery or stents.
The trials involve a two-step procedure. The trial was used in 45 patients with advanced heart disease.
In the first step, patients had liposuction to harvest some fat which is used to isolate adipose-derived regenerative cells (ADRC). Then the patient undergoes cardiac catheterization where the heart is imaged and the ADRCs are injected.
"The decision to place the trials on hold was based on a safety review of reported cerebrovascular events," according to the press release. "Symptoms occurred in three patients, of which two patients' symptoms fully resolved within a short period of time and the third patient has had substantial resolution of symptoms."
The statement also said these events had not been previously reported. Symptoms "appear to be related in part to the medical co-morbidities in the treated population and the complex nature of the procedures involved in the trial."
The company's shares fell 13 percent.
Timothy Henry, co-investigator of the trials, said the events occurred in both the experimental and control groups, but he is still blinded to the assignments because it was a double blind study.
He said they were "temporally related" and they were classified as strokes because the events lasted longer than 24 hours.
Henry also said that these complications are common with any invasive cardiac procedure.
The trial was suspended two months ago, but he is optimistic that they might be able to resume the trial in 2 months.
According to the press release, the company is working with the FDA's Data Monitoring Committee (DMC) to understand the adverse events and adjust the protocols accordingly.
Possible solutions include enrolling less sick patients or making the trial more restrictive, but then it would be more difficult to detect the effect of the treatment.