Kaigene Enters Into Exclusive Licensing Agreement With Taisho Pharmaceutical For Next-Generation Autoimmune Asset KG006 In Japan

Key Highlights:

• Taisho Pharmaceutical secures exclusive rights to clinically develop, register, and commercialize Kaigene's next-generation FcRn inhibitor, KG006, in Japan.
• Kaigene will receive a $5 million upfront payment and is eligible for up to a combined total of $22 million and ¥57.5 billion JPY (approximately $351 million) in development, regulatory, and sales milestone payments, plus tiered royalties on net sales.
• The agreement is expected to establish a robust framework for a three-way multi-regional clinical trial (MRCT) collaboration among Kaigene, Taisho and Celltrion, significantly accelerating the global clinical development of KG006.
• Taisho brings proven biologics expertise to the alliance, having extensive experience in the development and commercialization of Nanozora ®, an innovative anti-TNF VHH antibody therapeutic for the treatment of Rheumatoid Arthritis in Japan.

Rockville, MD and Tokyo /PRNewswire/ - Kaigene, Inc., a U.S.-based biotechnology company pioneering next-generation antibody therapeutics for autoimmune disorders, announced today that it has entered into an exclusive licensing agreement with Taisho Pharmaceutical Co., Ltd. ("Taisho"), a leading Japanese pharmaceutical company, for the exclusive development and commercialization of Kaigene's next-generation human neonatal Fc receptor (hFcRn) inhibitor, KG006, in Japan.

Under the terms of the agreement, Kaigene will receive a one-time upfront payment of $5 million. Kaigene is also eligible to receive up to a combined total of $22 million and ¥57.5 billion JPY (approximately $351 million) in aggregate development, regulatory, and sales milestone payments upon the achievement of specific clinical, regulatory, and cumulative net sales milestones. In addition, Kaigene will receive tiered royalties on net sales of the product in Japan. Taisho will assume full responsibility and hold exclusive rights for the clinical development, regulatory approval, and commercialization of KG006 within the Japanese territory.

Taisho is a distinguished pharmaceutical company with a proven, successful track record in the autoimmune space, notably having extensive experience in the development and commercialization of Nanozora®, an anti-TNF VHH therapeutic, in Japan. Through this strategic alliance, Taisho significantly bolsters its innovative autoimmune portfolio, while Kaigene secures an optimal local partner with deeply rooted clinical and commercialization capabilities and marketing infrastructure to ensure a rapid, smooth, and successful market launch for KG006 in Japan.

Importantly, this agreement complements Kaigene's existing global alliance with Celltrion Inc., which holds global development and commercialization rights to KG006 outside of Greater China and Japan. Subject to further clinical and regulatory planning, the new partnership is expected to provide a collaborative framework for Taisho's participation in the planned Multi-Regional Clinical Trial (MRCT) Phase 3 study led by Celltrion. This three-way clinical development cooperation among Celltrion, Kaigene, and Taisho aims to streamline global clinical development and potentially accelerate the development timeline for KG006.

"We are thrilled to partner with Taisho, a company with an exceptional legacy and validated capabilities in successfully bringing advanced antibody therapeutics to patients," said Minjae Shin, Chief Executive Officer and Founder of Kaigene, Inc. "In today's landscape, the ultimate key to success lies in uniting the unique strengths and complementary expertise of each partner to accelerate global clinical development and commercialization. Through this powerful collaboration, we can fast-track clinical trials, driving rapid market launches within our designated territories while jointly exploring additional high-value indications to maximize the full potential of KG006. Following our deep alliance with Celltrion as our global development leader, the integration of Taisho as our definitive Japanese partner completes a formidable 'One Team.' This collective synergy will maximize the potential of KG006 as a true best-in-class therapeutic in the global FcRn market."

About KG006
KG006 (also referred to by Celltrion as CT-P77) is a next-generation FcRn inhibitor with a novel antibody structure, being developed as a potentially best-in-class therapeutic that offers deep pathogenic antibody degradation, extended durability, and a convenient, patient-administered subcutaneous injection formulation. As a class, FcRn inhibitors possess immense market potential and commercial scalability across a broad spectrum of autoantibody-mediated autoimmune diseases.

About Kaigene, Inc.
Kaigene, Inc. is a biotechnology company focused on developing innovative antibody therapeutics that have the potential to transform the treatment paradigm for pathogenic antibody-mediated autoimmune diseases.

Leveraging its proprietary PDEG™ (Pathogenic Antibody Degrader) platform—a dual-acting technology optimized to selectively degrade pathogenic antibodies and suppress the B cells that produce autoantibodies—Kaigene has consistently validated its immunology pipeline through consecutive, high-profile global transactions. In April 2025, Kaigene entered into a collaboration agreement regarding its PDEG pipelines for undisclosed targets with a U.S. venture capital group specializing in the creation of emerging I&I biotech companies. Subsequently, in November 2025, Kaigene executed a global licensingagreement with Celltrion, under which Celltrion obtained worldwide rights for KG002, and global rights excluding Japan and Greater China for KG006 (CT-P77).

In addition, Kaigene is advanding its NanoBxTM (Nanobody-based Brain Shuttle) platform to enhance antibody penetration across the blood–brain barrier. Through this platform, the company is developing multiple therapeutic candidates aimed at addressing the significant unmet clinical needs in CNS autoimmune diseases, an area that remains largely unexplored.

For more information, please visit www.kaigene.com.

About Taisho Pharmaceutical Co., Ltd.
Headquartered in Tokyo, Japan, Taisho Pharmaceutical Co., Ltd. is a leading pharmaceutical company with a strong presence across both prescription pharmaceuticals (Rx) and over-the-counter (OTC) medicines. Taisho is highly regarded for its specialized research and commercialization capabilities in the autoimmune disease therapeutic area, notably highlighted by its successful in-house development and launch of the anti-TNF VHH antibody Nanozora®. Taisho continues to expand its biopharmaceutical footprint through strategic pipelines, licensing opportunities, and ongoing R&D investments. To learn more, please visit www.taisho.co.jp.