Human heart showing surrounding veins and arteries to represent cardiovascular disease as predicted by polygenic risk scores

Results from a Phase III trial of Australian biotech Mesoblast’s mesenchymal precursor cell therapy for heart failure show improved ejection fraction and lower risk of heart attack or stroke in recipients.

However, despite these signs of benefit, the study did not meet its primary endpoint, which was time to recurrent nonfatal hospitalization or urgent care events caused by decompensated heart failure, or successfully resuscitated high-grade symptomatic ventricular arrhythmias. This endpoint was similar between control and treatment groups and therefore did not reach statistical significance.

It is estimated that nearly 6.5 million Americans aged 20 years or older have heart failure. Although treatments are available, the outcome for many patients with heart failure, particularly those with reduced ejection fraction, is still poor.

The field of cell therapy is still at an early stage, but many groups and companies such as Heartseed, Help Therapeutics, BioCardia and Procella, among others, are working on new cardiovascular therapies. Heart failure is a target for many, but early positive results have proved difficult to reproduce.

The DREAM-HF trial, published in the Journal of the American College of Cardiology, was led by the Texas Heart Institute, using Australian cell therapy biotech Mesoblast’s candidate mesenchymal precursor cell therapy (MPCs; rexlemestrocel-L). It was a randomized, double-blind, multi-center study and it assessed the difference in outcomes between treatment with a single infusion of MPCs, or sham-control in 565 individuals with heart failure and reduced ejection fraction. Patients were followed up for an average of 30 months.

The primary endpoint, which took into account hospitalizations or urgent care events caused by heart failure or corrected symptomatic ventricular arrhythmias, was similar between the treatment and control group. Secondary endpoints and terminal cardiac events were also similar in the two groups.

The therapy did seem to show some benefits for patients and the risk for stroke or heart attack was 58% lower in the treatment group versus controls. The therapy was particularly effective in patients with biomarkers of inflammation and these individuals had a 75% reduction in risk for these cardiovascular events. Patients in the treatment group also showed significant improvements in left ventricular ejection fraction compared with controls.

“The results of DREAM-HF are an important step in understanding how cell therapy provides benefits in patients with chronic heart failure due to poor pump function,” said Emerson C. Perin, lead author and Medical Director at The Texas Heart Institute, in a press statement.

“The cells appear to work by reducing inflammation, increasing microvascular flow, and strengthening heart muscle. Locally, in the heart, the MPCs can protect cardiac muscle cells from dying and can improve blood flow and energetics. In large blood vessels throughout the body, the reduced inflammation resulting from the activation of MPCs may decrease plaque instability, which is what leads to heart attacks and strokes.”

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