Durham – September 16, 2026 -- Seismic Pharmaceuticals has enrolled the first patient in its global Phase 3 trial testing istaroxime for heart-failure-related cardiogenic shock, a condition with no FDA-approved pharmacologic therapy. The study, RESCUE HF-CS, targets approximately 600 patients recruited at clinical sites across the United States, Europe, China and South America.
No approved drug currently exists for cardiogenic shock, a high-mortality condition
Cardiogenic shock occurs when the heart cannot pump enough blood to meet the body's needs, cutting off oxygen delivery to vital organs. Despite advances in critical care, the condition continues to carry high complication and mortality rates, and no medication has been specifically approved to treat it.
Istaroxime's dual mechanism separates it from existing off-label inotropic therapies
Istaroxime is a first-in-class calcitrope combining Na/K ATPase inhibition with SERCA2a activation, designed to improve both systolic contraction and diastolic relaxation. Unlike inotropes currently used off-label for cardiogenic shock, istaroxime does not increase myocardial oxygen demand and instead reduces heart rate and arrhythmias.
Phase 3 program builds on four completed Phase 2 trials enrolling more than 350 patients
RESCUE HF-CS follows four prior Phase 2 programs in which more than 350 patients were enrolled, generating the clinical data supporting the pivotal trial's design. Additional details on trial eligibility and participating sites will be published on ClinicalTrials.gov and other clinical-trial registries.
Dr. Mandeep R. Mehra of Mass General Brigham Heart & Vascular Institute and Harvard Medical School, the study's principal investigator, said cardiogenic shock remains one of the most lethal conditions in cardiovascular medicine despite the absence of an approved pharmacologic therapy developed specifically for the syndrome. He said the trial represents an opportunity to determine whether istaroxime's dual mechanism can change the treatment paradigm for critically ill patients.