Zoll Medical’s TherOx SSO2 Therapy to Be Studied in ISO SHOCK IDE Trial

May 13, 2021—Zoll Medical Corporation, an Asahi Kasei company, announced that the FDA has approved an investigational device exemption (IDE) for a randomized prospective study evaluating the use of TherOx supersaturated oxygen (SSO2) therapy in patients presenting with ST-elevation myocardial infarction (STEMI) and cardiogenic shock and treated concurrently with a mechanical circulatory support device.

According to the company, the ISO SHOCK study will assess the safety and feasibility of SSO2 therapy in patients with this complex and highly fatal condition (a subset of high-risk patients with a mortality rate between 40% and 60%) compared to standard practice and outcomes demonstrated in the National Cardiogenic Shock Initiative (NCSI).

The study potentially lays the groundwork for future trials to benefit high-risk heart attack patients. SSO2 therapy is an FDA-approved treatment to significantly reduce cardiac muscle damage in heart attack patients after percutaneous coronary intervention. It is currently indicated for patients with LAD STEMI who are treated within 6 hours of symptom onset.

The ISO SHOCK study will randomize 60 patients in 20 sites across the United States to assess whether SSO2 therapy could provide benefit to these complex patients compared to the current standard of care. The primary safety endpoint will assess mortality at 30 days with the SSO2 therapy group compared to the control group as well as against the historical 32% mortality from the NCSI. The feasibility endpoints will measure completion of a 60-minute SSO2 infusion after successful PCI and obtaining an MRI 3 to 7 days after PCI.

The company stated that multiple clinical trials have demonstrated the efficacy of SSO2 therapy to reduce infarct size resulting from high-risk heart attacks such as left anterior descending (LAD) artery STEMI by delivering hyperoxemic levels of dissolved oxygen (7 to 10 times normal levels) directly to damaged heart muscle immediately after percutaneous coronary intervention (PCI).

A STEMI heart attack is associated with a two-fold increased risk of developing cardiogenic shock, which represents the highest risk category of STEMI with the greatest myocardial damage from ischemia. SSO2 therapy could potentially mitigate damaged tissue while improving left ventricular structure and function in this complex patient population.

SSO2 therapy is FDA-approved treatment to significantly reduce cardiac muscle damage in heart attack patients after percutaneous coronary intervention. It is currently indicated for patients with LAD STEMI and are treated within 6 hours of symptom onset.

William O’Neill, MD, and M. Babar Basir, MD, are coinvestigators of ISO SHOCK.

“Cardiogenic shock remains one of the most challenging diagnoses for interventional cardiologists to manage, especially in the setting of STEMI,” commented Dr. O’Neill in the company's announcement. “I have utilized SSO2 therapy in previous trials for anterior STEMI and seen positive results, and I think there is a significant potential benefit for this high-risk population as well.”