TherOx Completes Enrollment in Pilot Study of Next-Generation SSO2 Therapy as Adjunct to PCI for AMI

September 11, 2013—TherOx, Inc. (Irvine, CA) announced completion of enrollment in the multicenter pilot study of the company's second-generation system that delivers supersaturated oxygen (SSO₂) therapy for reduction of infarct size after an acute myocardial infarction (AMI).

The study, which commenced enrollment in February 2013, is being conducted under an investigational device exemption (IDE). The pilot phase of the IDE study enrolled 20 patients at three cardiac centers in the United States. Gregg W. Stone, MD, who is Professor of Medicine at Columbia University Medical Center in New York, New York, serves as Principal Investigator of the IDE trial.

In TherOx's press release, Dr. Stone commented, “We value the efforts of the investigators and research coordinators, and we believe the positive response we received is due to our investigators' eagerness for a new treatment option for further reducing infarct size in heart attack patients. Final infarct size correlates with improved cardiac function and mortality in heart attack patients, as demonstrated by several randomized clinical studies. Additional reduction of infarct size is an unmet clinical need that SSO₂ therapy may help address.”

According to TherOx, SSO₂ therapy is intended to provide interventional cardiologists with a treatment option beyond percutaneous coronary intervention (PCI) to salvage heart muscle in heart attack patients. The second-generation system that is now being studied builds on the success of the AMIHOT II trial and includes the additional benefits of shortening the treatment time to 60 minutes and broadening the treatment area to the entire left coronary system so that no ischemic area goes untreated. SSO₂ therapy is consistent with the 90-minute door-to-balloon initiative and supports the current guidelines for interventional cardiology procedures.

“The new system is user-friendly and allows for rapid and seamless setup by the cath lab staff immediately after PCI of the infarct-related artery,” commented study investigator Shukri David, MD, in the company's announcement. Dr. David is Section Chief of the Division of Cardiology at Providence Hospital near Detroit, Michigan.

The company explained that SSO₂ therapy is adjunctive to PCI and is intended to salvage the jeopardized myocardium and thus to reduce infarct size. SSO₂ therapy is designed to boost oxygen delivery to the heart muscle immediately after the coronary artery has been opened by PCI. The TherOx system creates SSO₂ therapy by mixing highly oxygenated saline with the patient's blood and delivering it through a catheter directly to the targeted ischemic area of the heart.

TherOx advised that in the United States, SSO₂ therapy is delivered by an investigational device and is not available for sale or distribution.

The first-generation system to deliver SSO₂ therapy has received European CE Mark approval and was successful in meeting the safety and effectiveness endpoints in the AMIHOT II trial.

TherOx noted that statistical results from the AMIHOT II trial of SSO2 therapy, together with PCI and stenting, demonstrated a relative reduction of 26% in infarct size compared to PCI and stenting alone. In addition, the finding of device effectiveness was supported by additional analyses that showed a 53% increased likelihood of having a small (< 5% damage of the left ventricle) infarct among SSO₂ therapy patients. The AMIHOT II results were published in 2009 by Dr. Stone, et al in Circulation: Cardiovascular Interventions (2009;2:366–375).