Repeated IV stem cell infusions go on trial for ischemic heart failure in new CATO study

Heart failure remains a major cause of disability and death, and regenerative approaches such as cell therapy have been explored for years with mixed results. Nearly all prior trials delivered a single dose of cells directly into the heart or coronary arteries. The authors argue that transplanted cells disappear quickly, so one dose likely limits benefit, while invasive delivery makes repeat dosing hard and is not feasible for many patients.

CATO (NCT06145035) is a Phase IIA, randomized, double-blind, placebo-controlled, multicenter trial testing intravenous umbilical cord-derived mesenchymal stromal cells in patients with ischemic heart failure. Sixty participants will be randomized to placebo, a single UC-MSC dose, or four repeated UC-MSC doses. Over 12 months, investigators will assess cardiac function and structure, functional capacity, quality of life, and biomarkers.

This is a design-and-rationale paper, so there are no efficacy or safety results. Enrollment began March 4, 2024, and 47 patients were enrolled by November 30, 2025. Enrollment is expected to finish by March 2026 and follow-up by March 2027.

The authors describe CATO as the first US trial of UC-MSCs for heart failure, the first of intravenous cell therapy for ischemic heart failure in the US, and the first randomized, double-blind, placebo-controlled test of repeated cell doses in chronic heart failure. If positive, intravenous repeat dosing could offer a cheaper, simpler, less invasive alternative to catheter-based delivery.

Caveats: the trial is small and early-phase, and the benefit of this strategy is unproven. Only the abstract was available. One author reports financial ties to cell therapy companies, though the authors state no company funded this work.