Researchers at Nanjing Drum Tower Hospital, affiliated with Nanjing University, have reported results from a phase 2 clinical study that tested a stem cell therapy for severe heart failure. The long-term follow-up results, released on a Wednesday and published in the journal Nature Medicine, showed that nine out of ten patients who received injections of heart muscle cells derived from induced pluripotent stem cells (iPSCs) had significantly better cardiac function at the 12-month mark compared with a control group.
The trial involved 20 patients, with ten receiving injections of stem cells that had been programmed to grow into heart muscle cells, and ten undergoing coronary artery bypass surgery as a control. The therapy aims to help ageing or damaged hearts grow new muscle tissue and restore function, addressing the fact that dead heart muscle cannot regrow.
Patients who received the stem cell injections showed notable improvements in several measures. Nine out of ten demonstrated significant recovery in heart function, with their cardiac function restored to only mild symptoms and allowing normal daily activity. They also performed better on a six-minute walking test, with improvements nearly double those seen in the control group. In comparison, only 60 per cent of the control group reached the same level of improvement, and one control patient died eight months after surgery.
The research team noted that no severe adverse events were observed in the treated patients. Two patients experienced tachycardia that peaked at two to three weeks after the procedure but resolved completely.
The trial is part of a larger effort to address the limited treatment options for severe heart failure. Patients with this condition often experience shortness of breath after walking a few steps, inability to lie flat, and frequent hospital visits. Heart failure can result from several end-stage cardiac diseases. While a heart transplant can cure the condition, donor hearts are scarce.
The findings highlight the potential of iPSC-based therapy, but researchers caution that future studies are needed to determine the risk-to-benefit ratio associated with this approach. The results were published in Nature Medicine, marking a significant step in the field of regenerative medicine for heart disease.