About Saisei Ventures
Saisei Ventures is a venture capital firm founded in 2020. It is primarily based out of Shinagawa, Japan. As of Apr 2026, Saisei Ventures is an active investor, having invested in 5 companies, with 1 new investment in the last 12 months. It primarily invests in Seed round in Japan based startups. Its investments are spread across Life Sciences and High Tech sectors. Most recently it participated in the $***** Seed round of Senno Therapeutics A lot of funds co-invest with Saisei Ventures, with names like Hakuhodo DY Ventures sharing a substantial percentage of its portfolio. Saisei Ventures has team of 9 people including 2 partners.Key Metrics
Team Members
Portfolio Count
Portfolio Sectors
Portfolio Locations
Rounds of Entry
Seed, Series A & 1 more
Portfolio Soonicorns
Deals in last 12 months
Saisei Ventures' List of All Investments
Saisei Ventures has a portfolio of 5 companies. Their most notable investments are in Craif and Kenai Therapeutics.Their portfolio spans across Japan and United States. They have invested in Life Sciences, High Tech, across Seed, Series A and 1 more. Here is the list of all investments by Saisei Ventures:
Developer of allogeneic cell therapies for neurological diseases. The company utilizes allogeneic induced pluripotent stem cell technology to advance neuron replacement therapeutics. The company's pipeline include RNDP-001 is an iPSC-derived, allogeneic dopamine progenitor cell therapy for the treatment of both idiopathic and inherited forms of Parkinson’s disease.
Key facts about Kenai Therapeutics
- Founded Year: 2022
- Location: San Diego (United States)
- Stage: Series A
- Total Funding till date: $89M
- Employee Count: 38 as on May 31, 2026
- Investors: The Column Group, Alaska Permanent Fund and 4 Others
- Latest Funding Round: Series A, Feb 29, 2024, $*****
- Highlight: Editors' Pick
2. Craif
Developer of a device for cancer detection. The company has developed a novel device that is used to collect and separate the microRNA secreted from cancer cells present in the urine. The device uses a combination of zinc oxide nanostructures and microflow channel technologies for the process and early cancer detection.
Key facts about Craif
- Founded Year: 2018
- Location: Tokyo (Japan)
- Stage: Series C
- Total Funding till date: $39.7M
- Employee Count: 53 as on May 31, 2026
- Investors: Aflac Innovation Partners, Mori Trust and 19 Others
- Latest Funding Round: Series C, Apr 28, 2025, $*****
- Highlight: Editors' Pick
3. Ryne Bio
Developer of treatments for neurological disorders. It offers a lead program RNDP-001 a cryopreserved iPSC dopamine neuron progenitor for the treatment of Parkinson’s Disease.
Key facts about Ryne Bio
- Founded Year: 2021
- Location: San Diego (United States)
- Stage: Series A
- Total Funding till date: $30M
- Employee Count: 34 as on Mar 31, 2026
- Investors: State of California and Saisei Ventures
- Latest Funding Round: Series A, Feb 26, 2024, $*****
Developer of chimeric antigen receptor T-cell therapies for cancer. The company has developed Eumbody System technology that enables to develop and detect scFv-based product candidates for therapeutic purposes. This technology has the potential to develop T-cell therapies for cancer, autoimmune and infectious diseases.
Key facts about Optieum Biotechnologies
- Founded Year: 2020
- Location: Japan
- Stage: Series A
- Total Funding till date: $8.45M
- Investors: ANRI, Keio Innovation Initiative and 3 Others
- Latest Funding Round: Series A, Jan 14, 2025, $*****
Developer of human cell therapies for treating fatal liver failure. This organization creates treatments using liver progenitor cells and organoids derived from human cells. These biological products are designed to address medical conditions in patients requiring organ transplantation. The technology focuses on the synthesis of cellular structures that replicate specific organ functions to provide therapeutic interventions for liver disease.
Key facts about Senno Therapeutics
- Founded Year: 2024
- Location: Tokyo (Japan)
- Stage: Seed
- Total Funding till date: $4.72M
- Investors: Mizuho Capital, One Capital and 1 Other
- Latest Funding Round: Seed, Apr 15, 2026, $*****
Saisei Ventures' Year-on-Year Investment Trends
Saisei Ventures has invested in 5 companies over the last 4 years, with an average of 1 new investment annually in the last 3 years. In 2025, it made 1 investment, while as of Apr 2026, it has made 1 investment in this year. Its most recent first time investment was in Senno Therapeutics and most recent follow-on round was in Kenai Therapeutics.Year | No. of Investments | ||
|---|---|---|---|
1st Round | Follow-on | Total | |
2026 (YTD) | 1 | 0 | 1 |
2025 | 1 | 0 | 1 |
2024 | 0 | 1 | 1 |
2023 | 0 | 0 | 0 |
2022 | 3 | 0 | 3 |
Saisei Ventures' Investments by Stage
Saisei Ventures has made 3 investments in Seed stage with an average round size of $4.72M, 1 investment in Series A stage with an average round size of $8.45M and 1 investment in Series B stage.Stage of entry | No. of Investments |
|---|---|
Seed | 3 |
Series A | 1 |
Series B | 1 |
Note: We have considered here, only first round of investments
Saisei Ventures' Investments by Sector
Saisei Ventures has a diverse portfolio, with companies operating in the Life Sciences and High Tech. Notably, it has invested in 5 Enterprise (B2B) companies, 5 Tech companies and 1 Tech hardware company.Sector | No. of Investments |
|---|---|
Life Sciences | 5 |
High Tech | 1 |
Note: We have considered here, only first round of investments
Saisei Ventures' Investments by Geography
Saisei Ventures has made most investments in Japan (3), followed by United States where it has made 2 investments.Country | No. of Investments |
|---|---|
Japan | 3 |
United States | 2 |
Note: We have considered here, only first round of investments
Saisei Ventures' recent investments
Saisei Ventures has made 1 investments in 2026 so far - Senno Therapeutics.Here are the most recent investments by Saisei Ventures:
Filter this listDate | Company | Location | Round Details | Round Amount | Co-Investors |
|---|---|---|---|---|---|
Apr 15, 2026 | Japan | Seed | 7755 | [+1] | |
Jan 14, 2025 | Japan | Series A | 5896 | ||
Feb 29, 2024 | United States | Series A | 4151 | ||
2022 | United States | Seed | 9921 | - | |
2022 | United States | Seed | 3272 | - |
Team profile of Saisei Ventures
Saisei Ventures has a team of 9 members including 2 Partners and 2 Venture Partners located in Japan and United Kingdom. Saisei Ventures' team does not sit on the board of any company as of now.Here is a list of all team members in Saisei Ventures:
Name | Designation | Location | Board Memberships | Contact Details |
|---|---|---|---|---|
Partner | Tokyo | - | ||
Partner | United Kingdom | - | ||
Venture Partner | Tokyo | - | ||
Venture Partner | - | - | - |
Co-investors of Saisei Ventures
Over the past 4 years, 29 investors have co-invested in Saisei Ventures's portfolio companies. This includes only funds.
- Invested before Saisei Ventures: Aflac Innovation Partners, ANRI and 3 others have invested in rounds before Saisei Ventures. There is 1 company where Aflac Innovation Partners has invested before Saisei Ventures and 1 company where ANRI has invested before Saisei Ventures.
- Top Co-investors of Saisei Ventures: 10 investors entered a company along with Saisei Ventures. These include investors like Hakuhodo DY Ventures (1 company).
- Invested after Saisei Ventures: A total of 14 investors have invested in Saisei Ventures's portfolio after their investments. Top Investors include State of California (2 companies), Alaska Permanent Fund (1 company) and Cure Ventures (1 company).
Recent News related to Saisei Ventures
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Saisei Ventures Launches Bridge-to-Biotech Venture Creation InitiativeBusiness Wire•Feb 09, 2026•Saisei Ventures
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Saisei Ventures launches executive fellows programme for Japan’s biotech leadership pipeline
BioSpectrum Asia•Apr 15, 2025•Saisei Ventures
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Saisei Ventures Launches Executive Fellows Program for Japan's Biotech LeadersBioSpectrum Asia•Apr 15, 2025•Saisei Ventures
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Saisei Ventures Launches Executive Fellows Program to Boost Japan's Biotech LeadershipBusiness Wire•Apr 14, 2025•Saisei Ventures
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Saisei Ventures Announces the Appointment of Dr. Sven Kili, MD, as PartnerBusiness Wire•Jan 09, 2025•Saisei Ventures, Antion Biosciences
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Kenai Emerges from Stealth With $82M Series A, Targets Parkinson’sBioSpace•Mar 01, 2024•Kenai Therapeutics, The Column Group, Cure Ventures, Saisei Ventures and 4 others
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Japanese public investment fund JIC investing $30m in Saisei BioventuresShareandstocks•Feb 08, 2023•Japan Investment Corporation, Saisei Ventures
