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Heartseed | Company Profile | iPS Cells & Regenerative Medicine

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COMPANY PROFILE / iPS CELLS & REGENERATIVE MEDICINE

Heartseed
The company that transplants allogeneic iPS cell-derived cardiac spheroids directly into the heart. It aims to file for approval in 2026, having parted ways with its partner Novo Nordisk in 2025

Heartseed is a biotech start-up spun out of Keio University. It forms ventricular cardiomyocytes made from iPS cells into small spheroids of about 1,000 cells each and transplants them into the hearts of patients with severe heart failure. Its lead pipeline product, HS-001, is transplanted by open-chest surgery at the same time as coronary artery bypass surgery. Analysis of the 10-patient Phase 1/2 trial (the LAPiS trial) is complete, and the company is targeting a marketing approval application within 2026. In September 2026 it also obtained the licence to market regenerative medicine products. It has no approved product yet, and almost all of its revenue has been milestone payments under its alliance with Novo Nordisk. That alliance was terminated in September 2025 at the partner's initiative, and the worldwide rights, including those outside Japan, have returned to Heartseed. This profile sets out what the company has invested, who it works with, what has been confirmed and what remains open, using primary sources only.

Primary sources: Heartseed's Annual Securities Report for the year ended December 2025 (filed 26 March 2026), its Interim Report for the year ending December 2026 (dated August 2026, covering January to June), timely disclosures, results briefing materials and press releases, and ClinicalTrials.gov. Last updated October 2026.

What this article covers
  1. Heartseed in 30 seconds, and where it stands in iPS cells and regenerative medicine
  2. The logo and how the name is written
  3. Where the company sits in iPS cells and regenerative medicine
  4. Scale of the company
  5. Resources committed to iPS cells and regenerative medicine
  6. Track record so far
  7. Plans ahead
  8. What the company is aiming for in iPS cells and regenerative medicine
  9. Partnership map
  10. Technologies, products and services
  11. The risks this company carries
  12. Glossary, references and claim-to-source audit

1. Heartseed in 30 seconds, and where it stands in iPS cells and regenerative medicine

LEGAL NAMEHeartseed Inc.The name comes from the resemblance of the spheroids to the seed of a plant
HEADQUARTERSShibaura, Minato-ku,
Tokyo
Established in November 2015. A biotech start-up from Keio University
LISTINGTSE Growth: 219AListed on 30 July 2024. Fiscal year ends in December (changed from October in 2025)
CATEGORYiPS cell & cell therapyTransplants allogeneic iPS cell-derived cardiomyocytes directly into the heart
HOW IT WORKSSpheroids of cardiomyocytes transplanted into the heart wallAims at "myocardial replacement": engrafted cells that support the heartbeat
APPROVAL STATUSNo approved productsHS-001: application targeted within 2026 (conditional and time-limited approval expected)
REVENUE¥3,026 millionYear ended December 2025 (14 months). Almost all from Novo Nordisk
EMPLOYEES43As of 31 December 2025 (2 temporary staff not included). 28 work in R&D
The one thing to grasp first

In terms of the three types of company in this field, Heartseed is an iPS cell & cell therapy company, and its treatment is of the kind in which the cardiomyocytes themselves are transplanted into the heart and made to engraft Sourced. The Annual Securities Report explains that its aim differs from approaches in which substances released by non-muscle cells help the heart (a paracrine effect). In June and August 2026 the company announced the results of the 10-patient trial. These were results from an open-label, uncontrolled study of 10 patients who also had coronary artery bypass surgery, and the figures compare each patient before transplant with the same patient 52 weeks later. Regulatory review is still ahead, and whether approval will be granted is not yet known. This article does not judge the merits of any product or whether a treatment is appropriate; it sets out the company's current state from primary sources.

2. The logo and how the name is written

A note on names: the company is Heartseed Inc. (its registered name is in Latin letters). It explains that the name reflects the resemblance of the spheroids to the seed of the balloon vine (English name: heartseed), and the hope that the spheroids will become a seed for the heart and save patients with severe heart failure. The product term for the spheroids is a registered trademark of the company (in Japanese). The development codes are HS-001 (open-chest delivery), HS-005 (catheter delivery) and HS-040 (from autologous iPS cells). Novo Nordisk, the partner until September 2025, is Novo Nordisk A/S of Denmark, which is the contracting party named in the filings.

Official site: https://heartseed.jp/

3. Where the company sits in iPS cells and regenerative medicine

Three types of company in iPS cells and regenerative medicine All are "regenerative medicine companies", yet they treat patients in entirely different ways Large pharma & strategic partners Genome editing & gene therapy iPS cell & cell therapy Enters by deal; has sales channels Rewrites genes directly to treat Makes cells, then transplants them Vertex / Novartis Bristol Myers Squibb and others CRISPR Therapeutics / Intellia Beam / Prime Medicine and others Fate / Sana Cuorips / Heartseed and others Funds for late trials and sales Editing tools and safety know-how Cell manufacturing and QC scale Thin in-house cell and gene base Hit by partners' change of course Costly to make; long-term safety Heartseed is in the right-hand type: it transplants iPS cell-derived cardiac spheroids into the heart Novo Nordisk ended the alliance in September 2025; global rights returned. Nothing is approved
Fig. 1 The three types of company in iPS cells and regenerative medicine, and where Heartseed sits. The classification is our own, and the example companies are drawn from those covered in this series Our calculation. That Heartseed's business is a single segment, myocardial regenerative medicine using allogeneic iPS cell-derived cardiac spheroids, is based on its Annual Securities Report.

In terms of how it treats patients, Heartseed is of the type that transplants cells derived from allogeneic iPS cells (cells from a donor rather than the patient) into a damaged organ and makes them engraft. It makes cardiomyocytes specialised to the ventricular muscle from iPS cells, raises their purity, forms them into small spheroids, and injects them with a needle into the wall of the heart Sourced. Cuorips's cardiomyocyte sheet, by contrast, is a product that is "attached to the surface of the heart", so the aim and the method of delivery differ (see our Cuorips profile). This is not a comparison of which is better. For an explanation of iPS cells themselves, see our explainer on iPS cells in this series; for the difference between allogeneic and autologous cells, see our explainer on autologous and allogeneic cells.

4. Scale of the company

Heartseed is a small research-led company whose revenue has depended almost entirely on a single partner. Amounts are in Japanese yen, and in 2025 the fiscal year-end was changed from October to December Sourced.

Metric (non-consolidated, ¥ thousands)FY ended Oct 2023FY ended Oct 2024Nov 2024 to Dec 2025 (14 months)Jan to Jun 2026
Revenue344,725873,6103,026,500467,370
Ordinary profit (loss)−1,456,584−818,581288,985−551,683
Net profit (loss) for the period (interim)−1,473,500−812,725190,608−554,307
Cash flow from operating activities−797,930−1,343,0391,080,526−529,128
Cash and cash equivalents at period-end4,588,1185,297,1666,836,0096,335,462
Employees (people, at period-end)393943-

Of the ¥3,026,500 thousand in revenue for the 14 months ended December 2025, ¥3,025,000 thousand (99.95% Our calculation) came from Novo Nordisk, recognised as development milestones were achieved. Operating cash flow was positive because of the collection of the related receivable (a decrease in accounts receivable of ¥768,250 thousand). The company explains that the ¥467,370 thousand of revenue in January to June 2026 is also milestone income recognised in the first quarter under the pre-termination agreement. The forecast for revenue in the year ending December 2026 is ¥467 million, all of it already booked in the first half. In other words, now that the alliance has ended, new revenue is hard to foresee until product sales begin (or a new alliance is signed). The company has no interest-bearing debt, and explains that cash and deposits make up about 90% of total assets.

A caution

The year ended December 2025 was an irregular 14-month year because of the change of fiscal year-end, so it cannot be compared simply with the previous (12-month) year. The profit (ordinary profit of ¥289 million) came from one-off milestone income under the contract with Novo Nordisk and does not show that the business has become profitable on its own. The full-year forecast for the year ending December 2026 is an operating loss of ¥2,207 million, an ordinary loss of ¥2,155 million and a net loss of ¥2,158 million Not yet confirmed.

5. Resources committed to iPS cells and regenerative medicine

Heartseed is a company focused on a single line of myocardial regenerative medicine, so the company's overall figures are the scale of this field. We separate what could be confirmed from what could not, covering people, money and outside relationships.

Type of resourceDetailsCategory
People (headcount)43 employees (2 temporary staff not included, 31 December 2025), average age 45.0, of whom 28 work in R&D. The Annual Securities Report describes President and Representative Director Keiichi Fukuda as having continued his research as a cardiologist at Keio University. He holds 13.74% of the shares in issue (the largest shareholder as of 30 June 2026)Sourced
People (sites)Head office in Minato-ku, Tokyo. Research space at a research base in Kawasaki (the Kawasaki Business Incubation Center), expanded in 2020. It has no manufacturing facilities and uses outside contract manufacturersSourced
Money (R&D expense)R&D expense for the 14 months ended December 2025 was ¥2,032,919 thousand (73.8% of selling, general and administrative expenses), mainly commissioned R&D. For January to June 2026 it was ¥779,927 thousandSourced
Money (funds)Cash and cash equivalents were ¥6,335 million at the end of June 2026. On 14 August 2026 it signed a special overdraft agreement with Sumitomo Mitsui Banking Corporation (¥2 billion, one year, unsecured and unguaranteed, floating rate). It raised ¥381 million in the year ended December 2025 through the exercise of stock acquisition rightsSourced
Money (manufacturing facilities)No investment in its own manufacturing facilities is stated in the Annual Securities Report (it states that it does not carry out production). Manufacture of the trial product is outsourced to Nikon Cell Innovation Co., Ltd.Could not be confirmed (own facilities)
Investment in and acquisition of other companiesNo subsidiaries or affiliates are stated in the Annual Securities Report (it states that it has no related companies). No acquisition of or investment in other companies is stated eitherCould not be confirmed
Technology brought in (licences)From Keio University, patents on purification of cardiomyocytes and others, by transfer or exclusive licence (from 2016). From iPS Academia Japan, a non-exclusive licence of the basic iPS cell patents (2019). The consideration is royalties tied to sales and similar; the rates are not disclosedSourced
Technology licensed outIn May 2021 it signed an exclusive worldwide alliance and licence agreement with Novo Nordisk (up to US$598 million in upfront payment and milestones combined, plus royalties on overseas sales). On 29 September 2025 the partner gave notice of termination, and the rights reverted to Heartseed. In September 2023 it also licensed out to a biotech company its intellectual property on removing undifferentiated iPS cells by fatty acid synthesis inhibitionSourced
Universities and public fundingKeio University (the source of the technology) and Shinshu University Hospital (first patient in the EMERALD trial). Under subsidy projects of AMED (the Japan Agency for Medical Research and Development): an evaluation platform for allogeneic iPS cell-derived cardiac spheroids (FY2018 to FY2020) and development of base technology for autologous iPS cell-derived cardiac spheroids (selected September 2023). Non-operating income of ¥58,511 thousand in the year ended December 2025 came mainly from AMED subsidy projectsSourced

6. Track record so far

WhenWhat happenedWhat it means
November 2015Established as a biotech start-up from Keio UniversityThe research of Keiichi Fukuda and colleagues was the starting point
2016Patents on cardiomyocyte purification and production of high-quality iPS cells transferred from Keio University. Joint research agreement signedTransfer of technology
March 2020Capital and business alliance with Itochu Chemical Frontier and Medipal HoldingsA base of funding and distribution
May 2021Exclusive worldwide alliance and licence agreement with Novo NordiskAlliance with a large pharma company
February 2023Dosing of the first patient in the domestic Phase 1/2 trial of HS-001 (the LAPiS trial) completedStart of clinical validation
July 2024Listed on the TSE Growth market. In the LAPiS trial, review by the safety evaluation committee of the low-dose group (5 patients) was completed and the trial moved on to the high-dose group-
January 2025Dosing of all 10 patients in the LAPiS trial completedEnrolment in the trial completed
29 September 2025Novo Nordisk gave notice of termination of the licence agreement, citing a focus on its core business areas and a review of strategy in other areas. The rights and intellectual property revertLost the partner, but the rights are back in-house
From November 2025The 30-day review of the clinical trial notification for HS-005 (catheter delivery) was completed (November). In January 2026 the 52-week follow-up of all 10 patients in the LAPiS trial was completedPreparation for the next trial; follow-up completed
1 June 2026Announced completion of the LAPiS analysis, including image reading by a third-party body. Said no safety concerns were found that would affect the policy for a marketing approval application, and that it is aiming to apply for approval within 2026Moved into application preparation
12 June 2026Announced that the first patient in the EMERALD trial of HS-005 (heart failure from dilated cardiomyopathy) had been treated (late March 2026, Shinshu University Hospital). The independent data safety monitoring committee approved continuing the trial based on data for four weeks after dosingThe first trial of catheter delivery of iPS cell-derived cardiac spheroids
14 to 17 August 2026¥2 billion special overdraft agreement with Sumitomo Mitsui Banking Corporation. Applied to the Tokyo Metropolitan Government for the licence to market regenerative medicine productsBuilding the set-up for commercialisation
29 August 2026Presented the 52-week topline results of the LAPiS trial in an invited lecture at the European Society of Cardiology Congress (ESC Congress 2026)Public presentation at an international congress
28 September 2026Obtained the licence to market regenerative medicine products from the Tokyo Metropolitan GovernmentPart of the set-up needed to sell after approval

Trial results (the company's announcement, within what the primary sources say)

What follows are the 52-week topline results of the LAPiS trial, which Heartseed published on 31 August 2026. The trial was open-label, uncontrolled and dose-escalating, with 10 patients; the figures compare each patient before transplant (week 0) with week 52, and the company's materials note them as read by the study site. As of writing, we have not been able to confirm an evaluation by regulators or a peer-reviewed paper. The results do not guarantee any treatment effect or safety, and are not medical advice.

Measure (week 0 → week 52)Low dose: 50 million cells (n=5)High dose: 150 million cells (n=5)
LVEDVI (left ventricular end-diastolic volume index, a measure of heart enlargement), mean141.1 → 122.2 mL/m² (maintained or reduced in 4 of 5)134.5 → 119.2 mL/m² (maintained or reduced in 4 of 5)
LVEF (left ventricular ejection fraction), mean25.0 → 31.0% (maintained or raised in 4 of 5)22.7 → 31.2% (maintained or raised in 5 of 5)
KCCQ-OS (quality of life and symptoms), mean66.0 → 62.7 points (maintained or increased in 2 of 5)75.8 → 95.5 points (maintained or increased in 5 of 5)
Six-minute walk distance, mean374.5 → 371.5 m (increased in 2 of 4; one value missing)462.6 → 500.2 m (increased in 4 of 5)
NYHA classMaintained or improved in 5 of 5Maintained or improved in 5 of 5
Safety (the primary endpoint is at week 26)No ventricular arrhythmia lasting 30 seconds or more, or requiring treatment. One patient had herpes zoster during the period of combined use of three immunosuppressants (it resolved with treatment). The company states that no safety concerns were found that would affect the policy for a marketing approval application

The Annual Securities Report states that all patients also had coronary artery bypass surgery (CABG), and that differences in cardiac function improvement by transplant site and by whether CABG was performed will be examined in future analysis. The immunosuppression is designed to start with three drugs immediately after transplant, at lower doses than for heart transplantation, and from week 26 to continue with one drug at a very low dose Sourced.

7. Plans ahead

HS-001 APPLICATIONTargeted within 2026In discussion with the PMDA. Use of conditional and time-limited approval expected
DOMESTIC LAUNCHTargeted within 2027Marketing licence obtained in September 2026. Price and volumes not published
HS-005 (CATHETER)EMERALD trial
14 patients planned
7 each for dilated cardiomyopathy and ischaemic heart disease. The first patient had dilated cardiomyopathy
OVERSEASWorldwide rights
held by the company
Whether to find a new partner or go it alone will be considered
Planned or in-development itemWhere it stands (company's account)Category
HS-001 (allogeneic iPS cell-derived cardiac spheroids, open-chest delivery)Analysis of all 10 LAPiS patients is complete, including image reading by a third-party body; the efficacy data are to be used in the marketing approval application. The trial has been notified to the PMDA as the "main trial" (see the glossary). In discussion with a target of a marketing approval application within 2026, and a target of starting domestic sales within 2027. As of 1 October 2026 we found no disclosure showing that the application has been filedNot yet confirmed
HS-005 (the same, catheter delivery)A domestic Phase 1/2 company-sponsored trial (the EMERALD trial): 7 patients each with ischaemic heart disease and dilated cardiomyopathy and severe heart failure, 14 in all. The high dose (150 million cells) is divided among up to 15 sites, and the primary endpoint is safety at week 26. The company describes it as the world's first trial of catheter delivery of iPS cell-derived cardiac spheroids. The first patient with dilated cardiomyopathy has been dosed, and the first patient with ischaemic heart disease has been decided. ClinicalTrials.gov (NCT07347197) still shows "not yet recruiting", so it may be behind on updatesNot yet confirmed
HS-040 (autologous iPS cell-derived cardiac spheroids)At the basic research stage. Because the patient's own cells are used, immune rejection is thought to be less of a concern, and applications are envisaged for patients using a ventricular assist device and for heart failure in children. Basic and non-clinical work is progressing with support from AMED subsidy projects. In November 2023 the company announced that it had stably made high-purity cardiomyocytes from iPS cell lines from several donors made by I PeaceNot yet confirmed
Overseas expansionIt holds worldwide rights to both HS-001 and HS-005, and receives at no extra cost the know-how and intellectual property that Novo Nordisk obtained during the alliance. Overseas, it is at the stage of considering manufacturing technology development and trial design for a global trial, and will consider later whether to secure a new partner to entrust the work to or to proceed itselfNot yet confirmed
What could not be confirmed

None of the following appears in the primary sources, or the company has not disclosed it Not yet confirmed.

The actual date of the approval application and the expected timing of approval / the selling price of HS-001 and the expected number of eligible patients / commercial manufacturing capacity and the terms of any commercial contract with a CDMO / when overseas trials will start / whether there is a new partner / the results of the EMERALD trial. The LAPiS results are the company's announcement, and we have not yet been able to confirm an evaluation of efficacy and safety by regulators or a peer-reviewed paper. This article does not use figures from press reports or market-size estimates.

8. What the company is aiming for in iPS cells and regenerative medicine

This section includes things the company does not say directly. We set them out as inferences within what the primary sources support, with the evidence for each.

What the evidence suggestsPrimary information it rests onCategory
The first priority is to obtain conditional and time-limited approval in Japan and start earning revenueThe management policy states that, after completing the LAPiS trial, the company will aim for conditional and time-limited approval in Japan and put in place a set-up that generates sales revenue. In 2026 it applied for and obtained the marketing licence, and describes this as moving into the phase of building a set-up for commercialisation and launchSourced
The eventual shape of treatment is to widen from HS-001 to HS-005, which is less burdensome for the bodyAfter demonstrating efficacy with HS-001, the Annual Securities Report says the company is considering developing HS-005 globally as a next-generation product. The target extends from ischaemic heart disease to dilated cardiomyopathyInference
The policy is to own no manufacturing facilities and leave production to outside CDMOsThe company explains that it does not carry out production, has completed the transfer of manufacturing technology to a CDMO, and is "asset-light". No investment in its own manufacturing facilities is statedInference
Overseas, it is likely to look again for a large partnerWhile keeping the worldwide rights, it says it will either secure a new partner and entrust overseas development to it, or proceed itself. Under the earlier arrangement, Novo Nordisk bore the cost of overseas development, manufacturing and salesInference
Revenue for now is close to zero until product sales beginThe revenue forecast for the year ending December 2026 is ¥467 million (already booked in the first half), with an operating loss of ¥2,207 million expected. All of past revenue came from Novo NordiskInference
One piece of evidence in more detail

The reading that "overseas it will look for a partner again" rests on how the contract framework has changed with the termination. Under the contract with Novo Nordisk, Heartseed carried forward clinical development in Japan, while Novo Nordisk held the rights, and bore the costs, of development, manufacturing and sales outside Japan; Heartseed could receive up to US$598 million in upfront payment and milestones combined Sourced. Now that the contract has ended and the rights have returned, the primary sources do not allow us to tell whether the company can fund overseas trials and manufacturing on its own. The reference figures are cash of ¥6,335 million at the end of June 2026, a half-year operating loss of ¥621 million, and an overdraft facility of ¥2 billion Sourced. From this we think it natural that the company lists securing a new partner as the first option for overseas Not yet confirmed. This inference says nothing about the merits of the company's policy or its prospects of success.

9. Partnership map

Partnership and support links centred on Heartseed Only links in the securities report, interim report and disclosures; press reports excluded Heartseed iPS spheroids Keio University Patent transfer, licences Novo Nordisk Global alliance (ended Sep 2025) Japan Lifeline Co-develops delivery catheter iPS Academia Japan Basic iPS patents (non-exclusive) I Peace Joint research, autologous iPS Nikon Cell Innovation Makes trial product (contract) SPLine (Medipal subsidiary) Transports spheroids, devices Linical Contract trial services (CRO) Itochu Chemical Frontier Capital alliance (March 2020) AMED (public funding) Subsidy projects (from FY2018) Joint development (dashed: ended) Contracted services Equity, public funds (dotted)
Fig. 2 Partnership and support links centred on Heartseed. Sources: the Annual Securities Report for the year ended December 2025, the Interim Report for the year ending December 2026, timely disclosures and results briefing materials. The figure includes only links stated in official materials, not links reported in the press. Novo Nordisk gave notice of termination of the contract on 29 September 2025. SPLine is a wholly owned subsidiary of Medipal Holdings.

How to read the figure: Heartseed takes its technology from Keio University, leaves manufacturing, transport and trial operations to outside parties, and concentrates itself on development and regulatory affairs. It used to have a contract under which Novo Nordisk held the rights, and bore the costs, of development, manufacturing and sales outside Japan; with that ended, it now holds the worldwide rights alone, and its partners are mainly contractors for practical work and supporters of funding Sourced.

10. Technologies, products and services

ItemDetails (from the Annual Securities Report and public materials)
HS-001A treatment in which cardiomyocytes specialised to the ventricular muscle are made from allogeneic iPS cells, formed into cardiac spheroids (clumps of about 1,000 cardiomyocytes) and transplanted into the heart wall by open-chest surgery at the same time as coronary artery bypass surgery. Low dose 50 million cells, high dose 150 million cells
HS-005A treatment delivering the same spheroids from inside the heart by catheter. Developed with Japan Lifeline as a system of two catheters: a mapping catheter and a delivery catheter. An electrode at the tip of the delivery catheter shows, through changes in the electrocardiogram, that the needle has reached the heart muscle
Delivery device (SEEDPLANTER)For open-chest delivery. The needle tip is rounded so as not to injure tissue, and has six side holes sized to the spheroids. A guide adapter fixed on the heart keeps angle and depth constant
Purification technologyThe glucose and glutamine that all cells need are removed from the culture medium and lactate, which only cardiomyocytes can use, is added; undifferentiated iPS cells and others die and cardiomyocytes are selected. Cardiomyocyte purity is stated as 98% or higher
Cell banks and manufacturingFrom an original iPS cell stock obtained from an outside body, master and working cell banks were made with the help of a CDMO and are maintained and managed by the company. Cardiomyocytes can be stored for a long time at ultra-low temperature, and are thawed to match the surgical schedule to make the spheroids. Manufacturing technology has been transferred to the CDMO
A materials engineer's view: purifying by changing only the medium, and turning frozen cells into stock

In this company's product, what matters for materials and processes is the composition of the culture medium itself Sourced. In general, when target cells are made from iPS cells, contamination by non-target or undifferentiated cells raises concerns such as tumour formation. Heartseed explains that it can purify by a simple step of exchanging the culture medium, using the metabolic difference that only cardiomyocytes can survive on lactate: remove glucose and glutamine from the medium and add lactate. Compared with methods that add equipment to sort cells, the simpler step could be a strength in large-scale manufacture Not yet confirmed.

The other point is cryopreservation. The design is to freeze purified cardiomyocytes as stock and thaw them to match the surgical schedule to make the spheroids, so the cryopreservation solution, survival after thawing and the spheroid-forming step all affect supply stability and cost. The specifications of the medium, freezing solution and forming equipment used have not been disclosed. See also our explainers in this series on cell manufacturing and cell banks, GMP, CDMO, and autologous versus allogeneic cells.

11. The risks this company carries

RiskDetailsCategory
The partner's departure and the loss of its revenue sourceNovo Nordisk, the source of almost all revenue, terminated the alliance in September 2025. The upfront payment and milestones of up to US$598 million under the contract can no longer be received. The revenue forecast for the year ending December 2026 is ¥467 million (already booked in the first half), with an operating loss of ¥2,207 million expectedSourced
The underlying trial is smallThe LAPiS trial was open-label, uncontrolled and dose-escalating, with 10 patients (5 low dose, 5 high dose), combined with coronary artery bypass surgery. The figures in the company's announcement compare each patient with his or her own pre-transplant state. Evaluation by regulators is still to comeSourced
Long-term safetyBecause the transplanted cells remain in the body for a long time, the company states that safety, including tumour formation and arrhythmia, has to be confirmed through an accumulation of non-clinical studies and long-term follow-up. It also states that it cannot completely rule out safety concerns not anticipated in the trialsSourced
Use of immunosuppressantsBecause the cells are allogeneic, the design combines three immunosuppressants immediately after transplant and continues one at a low dose from week 26. One patient had herpes zoster during the period of combined use of three drugs (it resolved with treatment)Sourced
Whether and when approval will be grantedAn application within 2026 and domestic sales within 2027 are both targets. The regulator may ask for additional trials or materials, and delays in filing or non-approval are always possibleInference
Reliance on outside manufacturingManufacture of the trial product is outsourced to a single company, Nikon Cell Innovation. Commercial manufacturing capacity and contract terms are not disclosed. Disasters or interruptions of supply could affect itInference
Emergence of competitorsThe company states that competition in iPS cell research is intense worldwide and that, for example, a competitor reaching the market first could have a material effect on its business. In March 2026 conditional and time-limited approval was granted to a product using iPS cells (Interim Report)Sourced
Funding outlookCash at the end of June 2026 was ¥6,335 million and the half-year operating loss was ¥621 million. It has secured a ¥2 billion overdraft facility, but building manufacturing and sales systems after approval, and overseas expansion, may need further fundsInference
Small staffWith 43 employees it is pursuing the approval application, a sales set-up, a second trial and overseas expansion at the same timeInference

12. Glossary

Cardiac spheroid
A tiny clump of about 1,000 cardiomyocytes made from iPS cells. A registered trademark of Heartseed (in Japanese).
Myocardial replacement (remuscularisation)
A treatment that aims to make up for lost heart muscle with transplanted cardiomyocytes, directly raising the heart's contractile force.
Allogeneic
Using cells from another person (a donor) rather than from the patient. Drugs to suppress rejection are needed.
Coronary artery bypass grafting (CABG)
Surgery that connects a blood vessel to bypass a blocked coronary artery. In the LAPiS trial it is done at the same time as transplanting the spheroids.
LVEF
Left ventricular ejection fraction. An index of the share of blood the heart pumps out with each beat.
LVEDVI
Left ventricular end-diastolic volume index. The volume of the left ventricle when it is dilated, corrected for body size. A measure of heart enlargement.
NYHA class
A classification of the severity of heart failure symptoms from class I to IV.
KCCQ-OS
The overall summary score of a questionnaire that scores heart failure symptoms and quality of life. The higher the score, the better.
Conditional and time-limited approval
A Japanese system that lets a regenerative medicine product go on the market early, with conditions and a time limit, when a small trial has confirmed safety and some efficacy can be expected. Efficacy is then confirmed after launch.
CDMO and CRO
A CDMO is a company that develops and manufactures on commission; a CRO is a company that carries out clinical trial work on commission.
Main trial (pivotal trial)
A trial notified on the PMDA's website as the final stage of domestic development, after which an approval application is expected.
Asset-light
Running a business lightly by leaving factories and other assets to outside parties instead of owning them.
Fig. 3 Concept diagram of how cardiac spheroids from allogeneic iPS cells are made, stored and transplanted into the heart (AI-generated concept; it does not depict actual products or facilities).

13. References

  1. Heartseed Annual Securities Report (10th fiscal year, November 2024 to December 2025, filed with the Kanto Local Finance Bureau on 26 March 2026) (in Japanese). History, business description, pipeline, trial summaries, management policy, risks, material contracts and R&D activities. https://ssl4.eir-parts.net/doc/219A/yuho_pdf/S100XUL5/00.pdf
  2. Heartseed Interim Report (first half of the 11th fiscal year, January to June 2026, August 2026) (in Japanese). Results of operations, major shareholders and R&D activities. https://ssl4.eir-parts.net/doc/219A/yuho_pdf/S100YX0K/00.pdf
  3. Heartseed Second-quarter (interim) results briefing materials for the year ending December 2026 (August 2026) (in Japanese). Progress against development targets, pipeline and balance sheet. https://ssl4.eir-parts.net/doc/219A/ir_material_for_fiscal_ym/210915/00.pdf
  4. Heartseed Press release, "52-week topline results of the Phase 1/2 trial (LAPiS) of allogeneic iPS cell-derived cardiac spheroids (HS-001) presented in an invited lecture at ESC Congress 2026" (31 August 2026) (in Japanese). https://heartseed.jp/news/assets/2026/08/b8af9c4bbc2cb3583655085e2067640f1b13730b.pdf
  5. Heartseed Timely disclosure, "Analysis results of the Phase 1/2 trial (LAPiS) of allogeneic iPS cell-derived cardiac spheroids (HS-001)" (1 June 2026) (in Japanese). https://ssl4.eir-parts.net/doc/219A/tdnet/2827696/00.pdf
  6. Heartseed Timely disclosure, "First patient treated in the Phase 1/2 company-sponsored trial of myocardial regenerative medicine HS-005 (catheter delivery)" (12 June 2026) (in Japanese). https://ssl4.eir-parts.net/doc/219A/tdnet/2834857/00.pdf
  7. Heartseed Timely disclosure, "Notice of conclusion of a special overdraft agreement" (14 August 2026) (in Japanese). https://ssl4.eir-parts.net/doc/219A/tdnet/2873646/00.pdf
  8. Heartseed Timely disclosure, "Notice of application for a licence to market regenerative medicine products" (17 August 2026) (in Japanese). https://ssl4.eir-parts.net/doc/219A/tdnet/2875044/00.pdf
  9. Heartseed Timely disclosure, "Notice of obtaining a licence to market regenerative medicine products" (28 September 2026) (in Japanese). https://ssl4.eir-parts.net/doc/219A/tdnet/2887710/00.pdf
  10. U.S. National Library of Medicine ClinicalTrials.gov NCT04945018 (LAPiS trial, Phase 1/2 of HS-001). https://clinicaltrials.gov/study/NCT04945018
  11. U.S. National Library of Medicine ClinicalTrials.gov NCT07347197 (EMERALD trial, Phase 1/2 of HS-005). https://clinicaltrials.gov/study/NCT07347197
  12. Heartseed Official website (source of the logo). https://heartseed.jp/

14. Claim-to-source audit

Claim in the articleCategorySource
Legal name, establishment (November 2015), head office, listing (TSE Growth 219A, July 2024), change of fiscal year-endSourcedReferences 1 and 12 https://ssl4.eir-parts.net/doc/219A/yuho_pdf/S100XUL5/00.pdf https://heartseed.jp/
43 employees, 28 in R&D, average age 45.0SourcedReference 1 https://ssl4.eir-parts.net/doc/219A/yuho_pdf/S100XUL5/00.pdf
Revenue, profit and cash flow (year ended October 2023 to January to June 2026)SourcedReferences 1 and 2 https://ssl4.eir-parts.net/doc/219A/yuho_pdf/S100XUL5/00.pdf https://ssl4.eir-parts.net/doc/219A/yuho_pdf/S100YX0K/00.pdf
99.95% of revenue from Novo Nordisk (¥3,025,000 thousand of ¥3,026,500 thousand)Our calculationReference 1 https://ssl4.eir-parts.net/doc/219A/yuho_pdf/S100XUL5/00.pdf Our own calculation
Earnings forecast for the year ending December 2026 (operating loss of ¥2,207 million and others), cash and deposits at about 90% of assets, no interest-bearing debtNot yet confirmedReference 3 https://ssl4.eir-parts.net/doc/219A/ir_material_for_fiscal_ym/210915/00.pdf
R&D expense (¥2,032,919 thousand, 73.8% of SG&A) and ¥779,927 thousand in January to June 2026SourcedReferences 1 and 2 https://ssl4.eir-parts.net/doc/219A/yuho_pdf/S100XUL5/00.pdf https://ssl4.eir-parts.net/doc/219A/yuho_pdf/S100YX0K/00.pdf
Special overdraft agreement (¥2 billion, Sumitomo Mitsui Banking Corporation)SourcedReference 7 https://ssl4.eir-parts.net/doc/219A/tdnet/2873646/00.pdf
Patents brought in from Keio University and iPS Academia JapanSourcedReference 1 https://ssl4.eir-parts.net/doc/219A/yuho_pdf/S100XUL5/00.pdf
The contract with Novo Nordisk (up to US$598 million), the notice of termination of 29 September 2025 and the return of rightsSourcedReference 1 https://ssl4.eir-parts.net/doc/219A/yuho_pdf/S100XUL5/00.pdf
Contracting and joint development with Nikon Cell Innovation, Linical, SPLine and Japan LifelineSourcedReference 1 https://ssl4.eir-parts.net/doc/219A/yuho_pdf/S100XUL5/00.pdf
AMED subsidy projects (FY2018 to FY2020, selected September 2023) and non-operating incomeSourcedReferences 1 and 4 https://ssl4.eir-parts.net/doc/219A/yuho_pdf/S100XUL5/00.pdf https://heartseed.jp/news/assets/2026/08/b8af9c4bbc2cb3583655085e2067640f1b13730b.pdf
Design of the LAPiS trial (10 patients; low dose 50 million cells, high dose 150 million cells) and primary endpointSourcedReferences 1, 4 and 10 https://ssl4.eir-parts.net/doc/219A/yuho_pdf/S100XUL5/00.pdf https://heartseed.jp/news/assets/2026/08/b8af9c4bbc2cb3583655085e2067640f1b13730b.pdf https://clinicaltrials.gov/study/NCT04945018
52-week topline results of the LAPiS trial (LVEF, LVEDVI, KCCQ-OS, six-minute walk and others)SourcedReference 4 https://heartseed.jp/news/assets/2026/08/b8af9c4bbc2cb3583655085e2067640f1b13730b.pdf
Completion of the LAPiS analysis (1 June 2026) and the target of an approval application within 2026SourcedReference 5 https://ssl4.eir-parts.net/doc/219A/tdnet/2827696/00.pdf
Design of immunosuppression (three drugs, then one from week 26) and combination with CABGSourcedReference 1 https://ssl4.eir-parts.net/doc/219A/yuho_pdf/S100XUL5/00.pdf
Design of the EMERALD trial (14 patients), the first patient (dilated cardiomyopathy) and approval by the data safety monitoring committeeSourcedReferences 1, 6 and 11 https://ssl4.eir-parts.net/doc/219A/yuho_pdf/S100XUL5/00.pdf https://ssl4.eir-parts.net/doc/219A/tdnet/2834857/00.pdf https://clinicaltrials.gov/study/NCT07347197
Application for (17 August 2026) and receipt of (28 September 2026) the licence to market regenerative medicine productsSourcedReferences 8 and 9 https://ssl4.eir-parts.net/doc/219A/tdnet/2875044/00.pdf https://ssl4.eir-parts.net/doc/219A/tdnet/2887710/00.pdf
The target of starting domestic sales within 2027, progress of HS-040, and the overseas policyNot yet confirmedReferences 1 and 3 https://ssl4.eir-parts.net/doc/219A/yuho_pdf/S100XUL5/00.pdf https://ssl4.eir-parts.net/doc/219A/ir_material_for_fiscal_ym/210915/00.pdf
Actual date of the approval application, selling price, commercial manufacturing capacity and start of overseas trialsNot yet confirmedNo outlook has been published. This article does not estimate them either
The three-type classification (large pharma / genome editing / iPS cell and cell therapy)Our calculationThis article's own grouping. Company names are examples from this series
Purification technology (using lactate), manufacture of the spheroids, and features of the delivery devicesSourcedReferences 1 and 4 https://ssl4.eir-parts.net/doc/219A/yuho_pdf/S100XUL5/00.pdf https://heartseed.jp/news/assets/2026/08/b8af9c4bbc2cb3583655085e2067640f1b13730b.pdf
The reading that the eventual shape of treatment is to widen from HS-001 to HS-005InferenceThis article's interpretation of how the Annual Securities Report positions HS-005
The reading that the policy is to own no manufacturing facilities and leave production to outside CDMOsInferenceThis article's interpretation of the statement that the company does not carry out production, and similar
The reading that overseas it is likely to look again for a large partnerInferenceThis article's interpretation of the policy after the rights returned and the change in the contract framework
The reading that revenue for now is close to zero until product sales beginInferenceThis article's interpretation of the earnings forecast and the dependence on Novo Nordisk
The risks of reliance on outside manufacturing, the funding outlook and small staffInferenceThis article's interpretation of the manufacturing contractor, cash and the number of employees
The risk that whether and when approval will be granted is uncertainInferenceThis article's interpretation of the fact that the application is still at the target stage

Last updated 1 October 2026 / Troy Technical
The figures in this article are based on Heartseed's Annual Securities Report, Interim Report, timely disclosures, results briefing materials and press releases, and on ClinicalTrials.gov. No research-firm estimates or press-based figures have been used. Passages marked "Inference" are this article's interpretation of the primary sources, not statements made by the company. This article does not recommend any treatment or product and is not medical advice.

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