TOKYO, Japan, June 2026
Heartseed Inc. announced the successful treatment of the first patient in its Phase I/II EMERALD clinical trial, evaluating HS-005, an investigational regenerative therapy using allogeneic iPS cell-derived cardiomyocyte spheroids delivered directly into the heart through a catheter system. The milestone represents the world’s first clinical trial to administer iPS cell-derived cardiomyocyte spheroids via catheter, marking a significant advancement in minimally invasive cardiac regenerative medicine for patients suffering from severe heart failure caused by ischemic heart disease or dilated cardiomyopathy. The first procedure was completed at Shinshu University Hospital in Japan, and the patient was discharged after an uneventful recovery. Following review of four-week safety data, an independent Safety Monitoring Committee approved continuation of the study in the dilated cardiomyopathy cohort.
HS-005 Advances Next-Generation Cardiac Regenerative Medicine
HS-005 is being developed as a next-generation regenerative therapy designed to repair damaged heart muscle using allogeneic induced pluripotent stem cell (iPS cell)-derived cardiomyocyte spheroids. Unlike Heartseed’s lead candidate HS-001, which requires open-heart surgery, HS-005 utilizes a specialized catheter system that enables endocardial delivery, allowing physicians to administer therapeutic cardiomyocyte microtissues from inside the heart. The technology is intended to provide a less invasive treatment option for patients with advanced heart failure while maintaining the regenerative benefits of cell-based therapy. Preclinical studies demonstrated that the spheroid structure improves cell retention and viability compared with individual cell injections, increasing the potential for successful engraftment and long-term therapeutic benefit.
First Patient Successfully Treated in EMERALD Phase I/II Study
The EMERALD study is a Phase I/II clinical trial evaluating the safety and efficacy of HS-005 in patients with heart failure with reduced ejection fraction (HFrEF) resulting from ischemic heart disease or dilated cardiomyopathy. The trial plans to enroll 14 patients, including seven patients in each disease cohort. According to Heartseed, the first patient suffering from dilated cardiomyopathy received treatment in late March 2026.
Advertisement
The procedure was completed without complications, and the patient’s postoperative course remained stable throughout the initial monitoring period. Investigators reported that catheter-based administration was completed efficiently, demonstrating the feasibility of delivering regenerative cardiac tissue through a minimally invasive approach. The company believes this achievement represents an important step toward expanding access to regenerative therapies for a growing population of patients with severe heart failure.
Potential to Restore Heart Function Through Remuscularization
Heartseed’s technology is designed to promote cardiac remuscularization, a process in which transplanted cardiomyocytes integrate into damaged heart tissue and contribute to improved contractile function. Once delivered into the myocardium, the cardiomyocyte spheroids are expected to engraft within the heart muscle, helping restore lost cardiac tissue while secreting angiogenic factors that stimulate new blood vessel formation around damaged regions.
Researchers believe the dual mechanism of remuscularization and neovascularization could provide meaningful clinical benefits beyond symptom management, potentially addressing the underlying causes of heart failure. With more than 65 million people worldwide living with heart failure and limited curative treatment options available outside heart transplantation, regenerative therapies such as HS-005 may represent a transformative new treatment approach.
Heartseed stated that it will continue advancing clinical development of HS-005 and remains committed to establishing innovative regenerative medicine solutions capable of improving outcomes for patients with severe heart failure through less invasive therapeutic approaches.
Source: Heartseed press release
