Alfresa Holdings Corporation (Headquarters: Chiyoda-ku, Tokyo; President and CEO: Ryuji Arakawa; hereinafter “Alfresa Holdings”), Mycenax Biotech Inc. (Headquarters: Hsinchu County, Taiwan;Representative: Pei-Jiun Chen, hereinafter “MBI”), Kidswell Bio Co., Ltd. (Headquarters: Chuo-ku, Tokyo; President and CEO: Shinya Benibayashi, hereinafter “Kidswell”), and Kaiohm Bioscience Co., Ltd. (Headquarters: Shibuya-ku, Tokyo; President and CEO: Masamichi Koike, hereinafter “Kaiohm”) have entered into a share subscription agreement (hereinafter “this Agreement”) stipulating that the four companies will subscribe to common stock issued by AlfenaX Biologics Corp. (Headquarters: Chuo-ku, Tokyo;Representative Director: Yoichi Koyanagi; hereinafter “Alfenax Biologics”) to underwrite the common stock issued by Alfenax Biologics (hereinafter “this Agreement”).

Alfenax Biologics is a wholly-owned subsidiary of Alfresa Holdings, established to conduct CDMO ^{Note 1} business for biopharmaceuticals and other products, as well as distribution business and any businesses incidental or related thereto. Following the completion of payment under this Agreement, the company is scheduled to become a joint venture owned by the four companies.

 Details

1. Background and Purpose of the Share Subscription Agreement Among the Four Companies

Biosimilars ^Note2(hereinafter “biosimilars”) are pharmaceuticals that possess the same quality, safety, and efficacy as the original biologic ^Note3, and are expected to contribute to expanding treatment options for patients and optimizing medical costs. Furthermore, from the perspective of ensuring a stable supply of pharmaceuticals, the importance of establishing a manufacturing infrastructure for biosimilars in Japan is increasing. The Ministry of Health, Labor and Welfare is advancing measures to promote the use of biosimilars and has set a target that^, by the end of fiscal year 2029, the number of active pharmaceutical ingredients (APIs) for which biosimilars account for at least 80% of the market should represent at least 60% of all APIs for which biosimilars are available ^Note4.

This project, involving four companies, was selected in May 2025 for the Ministry of Health, Labor and Welfare’s “Subsidy for Facility Development Costs at Medical Institutions, etc. (Project to Support the Development of Domestic Manufacturing Facilities for Biosimilars).”In November 2025, based on a shareholders’ agreement ^Note5signed by the four companies, Alfenax Biologics—the project operator—was established as a wholly-owned subsidiary of Alfresa Holdings. This agreement was signed to transform Alfenax Biologics into a joint venture among the four companies.

Upon completion of the payment under this agreement, the company is expected to become a four-party joint venture in which Alfresa Holdings and MBI will each hold a 45% stake, Kidswell will hold 7%, and Chiome will hold 3%.The four companies are currently preparing the site and carrying out other preparatory work to construct a manufacturing facility for biopharmaceuticals, including biosimilars (hereinafter “biopharmaceuticals, etc.”), on the premises of Alfresa Fine Chemical Co., Ltd. (Headquarters: Akita City, Akita Prefecture; President and CEO: Masaki Amano), a subsidiary of Alfresa Holdings. This manufacturing facility aims to establish an integrated production system covering everything from the manufacture of active pharmaceutical ingredients (APIs) to the formulation of biopharmaceuticals. Furthermore, by combining the Alfrezza Group’s manufacturing and distribution capabilities with MBI’s expertise in the biopharmaceutical CDMO business and its development and manufacturing know-how—along with Kidswell’s expertise in biosimilar development and product launch and Chiome’s expertise in antibody drug discovery and CMC development ^{Note 6}— , the joint venture will establish a foundation for its CDMO business for biopharmaceuticals, etc.

Currently, with the goal of commencing commercial production by the fiscal year ending March 2031, we are finalizing the business plan for Alfenax Biologics, which includes target products, manufacturing capacity, the timing of facility operations, and the scale of the business. The four companies will leverage their respective strengths to strengthen biopharmaceutical manufacturing capacity in Japan and contribute to the establishment of a stable supply system.

Note 1: CDMO (Contract Development and Manufacturing Organization): An organization that undertakes contract work ranging from the development of pharmaceutical manufacturing processes to the production of investigational drugs and commercial products

Note 2: A product that is equivalent and of the same quality as a reference biologic—a biologic drug already approved and marketed in Japan—and is sold by a different pharmaceutical company after the expiration of the reference biologic’s patent term or re-examination period.

Note 3: Refers to biologics already approved and marketed in Japan that serve as the reference standard for biosimilars. Biologics are pharmaceuticals with complex structures whose active ingredients consist of proteins and other substances produced by living organisms using genetic recombination or cell culture technologies; they are expected to be effective even against diseases that are difficult to treat with conventional chemically synthesized drugs.

Note 4: “Policy Guidelines for Promoting the Use of Biosimilar Products” (quoted from the Ministry of Health, Labor and Welfare website)

https://www.mhlw.go.jp/content/10807000/001310038.pdf

Note 5: For reference: Announced on November 25, 2025

”Signing of an Agreement Regarding the Establishment of a Joint Venture to Manufacture Active Pharmaceutical Ingredients and Formulations for Biosimilars”

https://ssl4.eir-parts.net/doc/2784/ir_material15/265432/00.pdf

Note 6: CMC (Chemistry, Manufacturing, and Controls): Research and development related to manufacturing methods and quality control to ensure the quality of pharmaceuticals

<Rendering of the Biopharmaceutical Manufacturing Facility>

2. Overview of Alfenax Biologics (as of November 9, 2026)

Note 7: The manufacturing facility is located on the premises of Alfresa Fine Chemical Co., Ltd. in Akita City, Akita Prefecture

Note 8: Following the completion of the capital contribution on November 25, 2026 (scheduled), the capital stock will be 1,20 1 million yen.

Note 9: After payment is completed on November 25, 2026 (scheduled), the ownership ratios will be: Alfresa Holdings 45%, MBI 45%, Kidswell 7%, and Chiome 3%.

■ About Alfresa Holdings

Alfresa Holdings is a corporate group with consolidated revenue exceeding 3.1 trillion yen, engaged in businesses ranging from the development and manufacturing of pharmaceuticals and other products to distribution and the operation of dispensing pharmacies. It also holds the No. 1 position in Japan ^{Note 10}in terms of sales of prescription drugs.

Guided by the group philosophy of “Creating and delivering vibrant lives for everyone,” the entire group supports the supply chain for pharmaceuticals and other products—which serve as social infrastructure—and contributes to a wide range of healthcare needs. The group is working to evolve and expand its comprehensive supply chain services, which span the entire process—from the introduction, development, and manufacturing of pharmaceuticals and other products to logistics, sales, post-marketing surveillance, and the “last mile.”

https://www.alfresa.com/

Note 10: Source: Drug Magazine, August 2026 issue, “Pharmaceutical Industry Rankings,” Top 5 Major Wholesale Groups (Drug Magazine, Inc.)

■About MBI

MBI is a pioneer in biopharmaceutical CDMO in Taiwan and provides a wide range of CDMO services, from development—including cell line establishment, manufacturing processes, analytical methods, and formulation—to commercial production and aseptic filling. Based in Taiwan, the company provides services globally.
https://www.mycenax.com/?lang=jp

■About Kidswell

Guided by its corporate philosophy of “Creating Value Through Biotechnology—Aiming for Care That Envelops Children, Families, and Society,” Kidswell has already launched four biosimilar products. The company is advancing its biosimilars business—which serves as a stable revenue base—and its cell therapy business (regenerative medicine), which has entered the clinical development stage and is expected to serve as a foundation for future exponential growth.We are dedicated to our daily research and development efforts to provide innovative drugs and treatments to patients suffering from illness and to contribute to the realization of a society where people can live bright and happy lives.

https://www.kidswellbio.com/

■ About Chiome

Chiome is a biotechnology company focused on discovering and developing antibody drug candidates for diseases with high unmet medical needs, leveraging its proprietary ADLib® system and multispecific antibody generation technologies, including Tribody®.In addition to its “Drug Discovery Business,” which focuses on in-house drug discovery, and its “Drug Discovery Support Business,” which provides high-quality technical services to pharmaceutical companies and others, the company promotes collaboration with pharmaceutical companies and startups as part of its IDD (Integrated Drug Discovery) business model to advance the biosimilar business and contribute to the sustainability of Japan’s drug discovery ecosystem.

https://www.chiome.co.jp/

<Contact Information Regarding This Matter>

Mycenax Biotech Inc.

(TEL: +886-2-26558951 Ext. 6102 email：liru.yeh@mycenax.com)

Alfresa Holdings, Corporate Communications Department

(TEL: +81-3-5219-5102 email:ir@alfresa.com )

Kidswell, Corporate Planning Department

(Email:info@kidswellbio.com )

Chiome, Investor Relations

(TEL: +81-3-6383-3561 email: ir@chiome.co.jp )