#Japan #Tokyo #ADC technology #CastBio #Real Tech Fund

CastBio Secures Funding Through J-KISS Options

CastBio Inc., headquartered in Chuo-ku, Tokyo, has recently announced a successful fundraising round through the issuance of J-KISS type stock acquisition rights, with the Real Tech Fund as the investor. The Real Tech Fund, managed by UntroD Capital Japan, is renowned for its focus on deep-tech investments, making it an apt partner for CastBio's ambitious plans.

This funding is set to enhance the company's research and development framework, particularly in advancing preclinical development for antibody-drug conjugates (ADCs) built on their proprietary VLK linker technology. CastBio, established in March 2026, has a unique foundation inherited from Rin Research Institute. The company aims to pioneer a novel drug delivery strategy through its CAST (Cancer Stromal Targeting) therapy, targeting insoluble fibrin (IF) present in tumor stroma. This innovative approach seeks to solve the complex challenges presented in the existing ADC landscape.

Objectives of Fundraising

The funds raised in this round will primarily be allocated towards:

• - Building a robust research and development infrastructure for anti-IF ADCs.
• - Accelerating the preclinical development of anti-IF ADCs.
• - Strengthening and protecting intellectual property.

Understanding J-KISS Fundraising

The J-KISS (Japanese Keep It Simple Security) method employed in this fundraising round is widely recognized in Japan for initial capital-raising among startups. This structure allows companies to defer business valuations until future funding rounds, thus facilitating quicker capital acquisition—a flexible financing method particularly suited to research-driven startups. The Real Tech Fund has a proven track record in financing numerous startups in deep-tech domains, positioning CastBio for significant growth in research and development activities.

Future Fundraising Strategy

Following this Pre-seed round, CastBio plans to pursue a Seed round, aiming to close by November 2026. The proceeds from this Seed round will be instrumental in conducting GLP safety trials for anti-IF ADCs, manufacturing investigational drugs for clinical trials, and laying groundwork for discussions with the PMDA and collaborations for trial initiation with the National Cancer Center.

To facilitate a swift fundraising process in subsequent rounds, CastBio is actively inviting additional investors to join following UntroD's participation.

Looking Ahead

CastBio is determined to accelerate its research and development efforts on its unique ADC drug discovery platform. The company seeks to foster collaborations with both domestic and international pharmaceutical firms, investors, research institutions, and contract manufacturing organizations. Ultimately, CastBio aims to maximize its corporate valuation and contribute to medical advancements by creating innovative cancer treatments.

Comments from Leadership

“Here at CastBio, we are extremely pleased to secure funding from the Real Tech Fund. ADC technologies are gaining significant global attention for their potential in treating difficult cancers. Our unique technology platform targeting tumor stroma represents considerable value in next-generation ADC drug discovery. We look forward to further strengthening our R&D capabilities during the upcoming Seed round and remain committed to the creation of groundbreaking cancer therapies,” commented Masaki Fujiwara, CEO of CastBio.

Company Overview

CastBio Inc.
Location: 2F Success Ginza East Building, 1-13-10 Tsukiji, Chuo-ku, Tokyo
CEO: Masaki Fujiwara
Established: March 30, 2026
Main Business: Research and development of pharmaceuticals, including antibody-drug conjugates (ADC), ADC-related technology development and licensing, as well as consulting services for drug discovery research.