Cytori Therapeutics, a company developing cell therapies based on autologous adipose-derived regenerative cells (ADRCs) to treat cardiovascular disease and other medical conditions, has placed enrollment in the ATHENA and ATHENA II trials on clinical hold and therefore anticipates that it will not be possible to complete enrollment of the ATHENA I trial prior to the end of 2014 as previously anticipated.

The decision to place the trials on hold was based on a safety review of reported cerebrovascular events. 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. Such events had not been previously reported in Cytori’s other cardiovascular trials and 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 US ATHENA and ATHENA II clinical trials are randomised, double-blind, placebo controlled studies designed to evaluate the safety and feasibility of adipose-derived regenerative cells (ADRCs) in heart failure patients with ischemic heart disease who are already receiving maximal therapy with no options for revasculariasation. The procedure involves a fat harvest through small volume liposuction, cardiac catheterisation, electromechanical mapping of the heart to determine where to inject ADRCs (or placebo), the actual ADRC (or placebo) injection and related data collection and monitoring activities.

Cytori has been working with the FDA, an independent Data Monitoring Committee (DMC), trial investigators and external expert consultants to fully understand any adverse events and to carefully define adjustments to the protocol intended to minimise risks to patients and to improve the benefit to risk profile of the study.

Adverse events are expected in trials in which participants suffer from advanced cardiac disease and protocol revisions during phase II safety and feasibility studies in compromised populations are common. Cytori is committed to refining the trial protocol as needed, to mitigate risks as much as possible. Updated information regarding enrollment projections will be communicated upon final protocol revisions and agreement amongst the investigators, the DMC and FDA as to the safety and feasibility of continuing the trial as amended.