What RAINBOW does

RAINBOW Co., Ltd. (株式会社RAINBOW) is a Sapporo, Japan-based clinical-stage biotechnology company founded in August 2019 as a Hokkaido University spin-off, built on approximately twenty years of neurosurgery research on brain regeneration. The company develops autologous (patient-derived) bone marrow mesenchymal stem cell (MSC) products for chronic stroke, where current medical consensus holds that functional recovery is no longer achievable beyond six months post-onset. Its lead product HUNS001 targets chronic cerebral infarction and is in an active physician-initiated Phase I/IIa trial (RAINBOW2a), with two patients dosed as of February 2026 against a planned enrollment of eight; a second product HUFF-01 is in development for chronic intracerebral hemorrhage with a Phase I/IIa notification submitted to PMDA in October 2023. The scientific rationale centers on autologous MSCs enabling long-term brain engraftment (over five years confirmed in prior prototype studies) and functional neural network recovery in the chronic phase, differentiating the approach from allogeneic competitors that target only the acute or subacute window.

The company's core technology stack comprises a proprietary automated, closed-system cell culture process intended to overcome the labor-intensity and cost barriers that historically limited autologous cell therapy economics, paired with a planned Central CPC plus Local CPC hub-and-spoke supply chain model designed to enable nationwide distribution from bone marrow harvest at local hospitals through three to four weeks of central culture to same-day delivery for transplantation. Manufacturing scale-up is being co-developed with Daicel Corporation and Daisen Membrane Systems under a January 2024 joint development agreement, and the company holds an exclusive license from Mizuho (November 2022) to patents covering stereotactic brain surgery devices relevant to the transplantation procedure.

RAINBOW is pre-revenue, with all activity centered on clinical development and regulatory preparation rather than commercial sales. The go-to-market model targets a network of university hospitals operating Local CPCs, regional base hospitals, and comprehensive stroke centers post-approval, with physician-initiated clinical trials at Hokkaido University Hospital currently serving as the primary validation channel. As of late 2024, the company has seven to eight employees, is headquartered at the Hokkaido University Food and Medical Innovation International Hub in Sapporo, and is capitalized at approximately 100 million yen of registered capital with total disclosed funding of roughly 657 million yen across three capital raises between 2020 and 2026.

Name

RAINBOW

Legal name

株式会社RAINBOW

Website

https://rainbowinc.co.jp

Company type

Private

Founded year

2019

Operating status

Operating

Headcount range

1–10 employees

Short description

RAINBOW is a Sapporo-based, pre-revenue clinical-stage biotech developing autologous bone marrow mesenchymal stem cell therapies (HUNS001, HUFF-01) for chronic stroke patients, using proprietary automated cell culture technology and a planned Central CPC plus Local CPC distribution network.

Ownership category

akta.pro rank

Product category

Regenerative Medicine / Cell Therapy

NAICS

Scientific Research and Development Services (5417)

SIC

Biological Products, (No Disgnostic Substances) (2836)

akta.pro primary industry

Stem Cell Therapies (MSC/iPSC/HSC-derived) (HLAAABAE)

akta.pro secondary industries

Stem Cell–Based Regenerative Therapies (HLAAAGAA), Cell Therapy Developers (Autologous) (HLAAABAA)

Keywords

• Regenerative medicine
• Stem cell therapy
• Mesenchymal stem cell products
• Cell therapy manufacturing
• Autologous cell processing

Headquarters

HQ city

Kita

HQ country

Japan

HQ region

Asia

Offices2 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Technology or R&D, Personnel, Operations, Marketing or Sales, Infrastructure

Revenue model

1. Regenerative Medicine Product Sales: The company is developing and seeking regulatory approval for its autologous MSC products (HUNS001, HUFF-01) for treating chronic stroke patients. Revenue will be generated through manufacturing and selling regenerative medicine products to hospitals and medical institutions upon regulatory approval. The company is currently in clinical trial stage and has not yet commercialized any products.

Go-to-market motion2 records

Distribution channels1 record

Marketing channels4 records

Core offering

RAINBOW is a clinical-stage regenerative medicine company developing autologous bone marrow-derived mesenchymal stem cell (MSC) products for chronic stroke patients. Its lead product HUNS001 targets chronic cerebral infarction (6+ months post-stroke onset), while HUFF-01 targets chronic cerebral hemorrhage. The company uses proprietary automated closed-system cell culture technology and a Central CPC + Local CPC supply chain to enable nationwide hospital delivery of autologous cell therapies.

Product overview

RAINBOW is a regenerative medicine company developing autologous (patient-derived) stem cell therapies for neurological conditions. The company's core product portfolio consists of two main pipeline products: HUNS001, an autologous bone marrow mesenchymal stem cell (MSC) product for chronic cerebral infarction currently in Phase I/IIa clinical trials; and HUFF-01, a related MSC product for chronic cerebral hemorrhage in pre-clinical/early clinical stages. Both products leverage the company's proprietary automated culture technology and Central CPC (Cell Processing Center) supply chain model for scalable manufacturing and nationwide distribution.

Differentiator

Problem solved

Functional benefit

Brands

• HUNS001: Autologous bone marrow mesenchymal stem cell (MSC) product for treatment of chronic cerebral infarction (6 months or more post-onset). The company's primary development product.
• HUFF-01

Products and services

• HUNS001 Autologous bone marrow-derived mesenchymal stem cell (MSC) product for treating chronic cerebral infarction (stroke occurring 6 months or more after onset). The product is manufactured from the patient's own bone marrow and transplanted directly into the brain to induce neurogenesis and restore neural network function. Currently in Phase I/IIa clinical trials.
• HUFF-01 Autologous bone marrow-derived mesenchymal stem cell (MSC) product for treating chronic cerebral hemorrhage (brain bleeding) in the chronic phase. Currently in pre-clinical/early clinical development stage with IND submitted to PMDA in October 2023.

Quantifiable outcome

• Patients who could not walk due to stroke recovered walking ability in Phase I clinical trial of HUNS001
• +2 more outcomes

Named customers1 record

Segments2 records

Ideal customer profiles2 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature4 records

Partnerships

Eight partnerships are on record, tiered core and supportive.

• 北海道大学医学部 (Hokkaido University Graduate School of Medicine)coreStrategic or Co-development Partner · 1 May 2025Joint research with Hokkaido University Graduate School of Medicine and Japanese Red Cross Hokkaido Block Blood Center on successful manufacturing of human platelet lysate from waste blood leukocyte reduction filters for MSC culture supplement.
• 日本赤十字社北海道ブロック血液センター (Japanese Red Cross Hokkaido Block Blood Center)supportiveStrategic or Co-development Partner · 1 May 2025Collaborated research on platelet lysate manufacturing from waste blood materials for use as effective culture supplement in MSC proliferation.
• 北海道大学病院脳神経外科 (Hokkaido University Hospital Neurosurgery)coreImplementation/ SI/ Consulting Partner · 1 December 2024Physician-initiated clinical trial partnership for RAINBOW2a study. Professor Fujimura's department leads the Phase I/IIa trial for HUNS001 in chronic stroke patients.
• 株式会社ダイセル (Daicel Corporation)coreStrategic or Co-development Partner · 1 January 2024Joint development agreement signed January 2024 for cell product manufacturing technology development with Daicel Corporation and Daisen Membrane Systems Corporation.
• ダイセン・メンブレン・システムズ株式会社 (Daisen Membrane Systems Corporation)coreStrategic or Co-development Partner · 1 January 2024Joint development agreement signed January 2024 with Daicel Corporation for cell product manufacturing technology.
• ミズホ株式会社 (Mizuho Co., Ltd.)coreOEM/ Whitelabel/ Licensing Partner · 1 November 2022Exclusive license agreement for patent 'Puncture Needle, Puncture Needle Kit, and Stereotactic Brain Surgery Device' in Japan for brain surgery procedures related to cell transplantation.
• テルモBCT株式会社 (Terumo BCT)coreStrategic or Co-development Partner · 1 June 2020Selected together with Hokkaido University for Ministry of Economy, Trade and Industry's Strategic Core Technology Advancement Program (サポイン). Collaboration on foundational technology development for cell processing.
• 北海道大学 (Hokkaido University)coreStrategic or Co-development Partner · 1 March 2020Joint research agreement signed in March 2020 for development of BMSC (bone marrow stromal cell) therapy technology. The company originated from approximately 20 years of Hokkaido University neurosurgery research on brain regeneration. Founding scientists include university faculty.

Scale indicators10 records

Recent moves6 records

Expansion highlights6 records

Direct peers

• SanBio: SanBio develops allogeneic stem cell therapies (SB623) for neurological conditions including chronic stroke. CSO Kawabori previously worked at SanBio, making it a directly comparable peer in stroke cell therapy. Unlike RAINBOW's autologous approach, SanBio uses allogeneic bone marrow-derived cells targeting subacute stroke.
• Healios: Japanese regenerative medicine company developing allogeneic stem cell therapies (HLCM051 / MultiStem) for ischemic stroke and ARDS. Kawabori also has prior experience at Healios. Operates under Japan's Regenerative Medicine Law with similar regulatory pathway to RAINBOW.
• Athersys: US-based clinical-stage company developing MultiStem, an allogeneic stem cell therapy for ischemic stroke (Phase III program) and other indications. Direct peer in stroke cell therapy category, though using a different cell type and allogeneic platform.
• BrainStorm Cell Therapeutics: Clinical-stage company developing NurOwn, an autologous MSC-based therapy for neurodegenerative diseases including ALS and progressive MS. Closely comparable to RAINBOW's autologous MSC platform applied to neurological indications.
• Hope Biosciences: Clinical-stage company developing autologous adipose-derived stem cell therapies for various neurological and autoimmune conditions. Comparable autologous cell therapy business model targeting chronic neurological disease populations.
• Pluristem Therapeutics: Clinical-stage company developing placenta-derived allogeneic cell therapy products (PLX cells) for multiple indications including ischemic stroke and muscle injury. Comparable cell therapy platform with neurological indication overlap, though using allogeneic placenta-derived rather than autologous bone marrow-derived cells.

Broad incumbents

• Mesoblast: Established commercial-stage company with multiple MSC-based therapeutic candidates across inflammatory and cardiovascular indications. Broader portfolio than RAINBOW but uses similar mesenchymal stem cell platform; well-capitalized incumbent in the MSC space.

Regional players

• Heartseed: Tokyo-based clinical-stage regenerative medicine company developing iPSC-derived cardiomyocytes for heart failure. Japanese peer operating under the same Regenerative Medicine Law framework; outside director Kaneko serves as Part-time Director. Indirect comparison as a Japanese regenerative medicine company navigating similar regulatory pathway.

Others

• RoosterBio: MSC-focused manufacturing and technology company supplying MSC production platforms and cell banks to therapy developers. Adjacent player — potential supplier/enabler to autologous MSC therapy developers like RAINBOW rather than a direct competitor.
• CytoTherapeutics: Cell therapy infrastructure and services provider supporting MSC and other cell therapy development. Adjacent enabler in the cell therapy supply chain rather than a direct stroke therapy competitor.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks6 records

Key highlights7 records

Customer concentration

• Facebookfacebook.com/rainbowjapan

Revenue estimate

Valuation estimate

Number of profiles

Profiles9 records

Funding overview

Funding rounds1 record

Investors4 records

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about RAINBOW