Heartseed Inc.
Heartseed Inc. is a leading Japanese clinical-stage biotechnology company pioneering the field of cardiac regenerative medicine. Founded in 2015 as a spin-off from the Keio University School of Medicine, the company is headquartered in Tokyo, Japan, and was established by Dr. Keiichi Fukuda, a renowned professor of cardiology.
The company's core mission is to replace lost heart muscle cells and cure advanced heart failure, a condition that has historically lacked definitive treatment options outside of heart transplantation. Heartseed achieves this through its proprietary technology, which develops highly purified ventricular cardiomyocytes (heart muscle cells) derived from induced pluripotent stem cells (iPSCs).
To ensure the transplanted cells successfully integrate and survive in the patient's heart, Heartseed utilizes a unique "cardiomyocyte spheroid" approach. By grouping approximately 1,000 iPSC-derived heart cells into micro-tissue clusters, the company significantly improves cell retention and structural graft efficiency within the damaged heart wall.
Its flagship therapeutic candidate, HS-001, is currently undergoing clinical trials for patients suffering from severe ischemic heart failure. Backed by strategic global partnerships—notably a high-profile exclusive collaboration and license agreement with Novo Nordisk—Heartseed represents the cutting edge of cell therapy, moving the medical community closer to an era where heart disease can be reversed rather than merely managed.
Heartseed is gaining attention in 2026 following the first patient dosing in its Phase I/II EMERALD trial of HS-005, a catheter-delivered therapy using iPSC-derived heart muscle cell spheroids for severe heart failure. The minimally invasive approach could offer an alternative to the open-heart surgery required for its earlier HS-001 program. In February 2026, Heartseed was also selected for the JPX Start-Up Acceleration 100 Index, underscoring its growing profile in Japan’s life sciences sector.
Heartseed is making headlines with HS-005, the world’s first clinical trial of catheter-based delivery of iPSC-derived cardiomyocyte spheroids. Unlike its lead candidate HS-001, which requires open-heart surgery, HS-005 uses endocardial catheter delivery, offering a potentially less invasive approach to cardiac regenerative medicine.
“Heartseed is advancing next-generation heart failure treatment through iPSC-derived cell therapies, with HS-005’s catheter-based approach marking a key step toward less-invasive cardiac regeneration.”
HS 001
Mechanism of Action: Cell replacements
Drug Class: Induced pluripotent stem cell therapies Originator: Heartseed Inc. Indication: Heart failure
Heartseed’s HS-001 is an allogeneic iPSC-derived cardiac cell therapy designed to treat heart failure with reduced ejection fraction (HFrEF), including dilated cardiomyopathy, prior myocardial infarction, and dilated-phase hypertrophic cardiomyopathy. The therapy involves transplanting clusters of purified heart muscle cells into the patient’s heart to restore cardiac function.
The Phase I/II LAPiS trial delivered promising results, with no major safety concerns and encouraging efficacy signals. Based on these findings, Heartseed plans to seek marketing approval for HS-001 in Japan, marking an important step toward bringing iPSC-based cardiac regenerative therapy to patients with severe heart failure.
HS 005
Mechanism of Action: Cell replacements
Drug Class: Induced pluripotent stem cell therapies Originator: Heartseed Inc.
Manufacturer: Nikon CeLL innovation Co., Ltd. (NCLi) Indication: Heart failure
Heartseed has dosed the first patient in its Phase I/II EMERALD trial of HS-005, an investigational iPSC-derived cardiomyocyte spheroid therapy for patients with severe heart failure with reduced ejection fraction (HFrEF) caused by ischemic heart disease or dilated cardiomyopathy. Delivered directly to the heart through a catheter, HS-005 represents the world’s first clinical trial using catheter-based delivery of iPSC-derived heart muscle cells, potentially offering a less invasive approach to cardiac regeneration.
Nikon CeLL innovation (NCLi), a subsidiary of Nikon, manufactures the purified cardiomyocyte spheroids for HS-005 under contract to Heartseed. The two companies plan to continue their collaboration to support future commercial supply in Japan, combining their manufacturing expertise and technologies to advance the practical use of regenerative medicine and improve patients’ quality of life.
Market revenue of Heartseed Inc.
Heartseed Inc.’s market revenue has remained volatile over the past five years, reflecting its development-stage business model and milestone-driven income. Revenue declined from JPY 499 million in 2022 to JPY 345 million in 2023, before rising sharply to JPY 874 million in 2024 and JPY 3.03 billion in 2025. The 2025 surge was primarily driven by development milestone income from Novo Nordisk, enabling the company to achieve its first annual profitability, with an operating profit of JPY 272 million and net profit of JPY 190 million.
For 2026, revenue is forecast to fall 85.1% to JPY 451 million, alongside an expected operating loss of JPY 2.21 billion, as milestone-related income declines and Heartseed increases investment toward commercialization. Despite the near-term decline, the company is advancing its key pipeline, with HS-001 targeting a Japanese approval filing in 2026 and potential launch in 2027, while HS-005 is progressing through its Phase I/II EMERALD study.
Five-year market revenue of Heartseed Inc. (2022- 2026)
Fig 14: Market revenue of Heartseed Inc.
Advancing cardiac regeneration through iPSC-derived cardiomyocyte spheroid therapy for heart failure
Heartseed HS-001 is an innovative regenerative cell therapy designed to treat Heart Failure with Reduced Ejection Fraction (HFrEF). The therapy utilizes allogeneic induced pluripotent stem cell (iPSC)-derived cardiomyocytes that are formed into spheroids and delivered directly into damaged heart muscle through intramyocardial injection. By engrafting and expanding within the myocardium, the transplanted cardiomyocytes are intended to improve cardiac contractility and restore heart function. HS-001 is being developed for patients with HFrEF, including those with Dilated Cardiomyopathy (DCM), Old Myocardial Infarction (OMI), and Dilated-phase Hypertrophic Cardiomyopathy (D-HCM), addressing a significant unmet need in cardiovascular disease treatment.
