LAUSANNE, Switzerland, July 30, 2026
AB2 Bio Ltd. has reached a major commercial and regulatory milestone after Nippon Shinyaku Co., Ltd. exercised its exclusive option to obtain U.S. commercialization rights for Tadekinig alfa, triggering a $30 million option exercise payment to the Swiss biotechnology company. The agreement follows positive interactions with the U.S. Food and Drug Administration (FDA) and supports the continued development of Tadekinig alfa, an investigational biologic targeting Primary Monogenic IL-18-Driven Hyperinflammatory Syndrome in patients with NLRC4 and XIAP mutations. The ultra-rare pediatric disorder currently has no FDA-approved treatment, making the collaboration an important step toward addressing a significant unmet medical need. Under the expanded agreement, AB2 Bio remains responsible for Biologics License Application (BLA) preparation and U.S. regulatory activities, while retaining worldwide rights outside the United States and for all other disease indications. In addition to the upfront payment, AB2 Bio is eligible to receive up to $600 million in future development, commercial milestone, and royalty payments, reinforcing the strategic value of the partnership and highlighting growing confidence in the therapeutic potential of Tadekinig alfa.
Nippon Shinyaku Expands Partnership Through U.S. Commercialization Rights
The expanded collaboration strengthens the partnership originally established in 2025, with Nippon Shinyaku exercising its exclusive commercialization option after encouraging regulatory discussions and continued clinical progress. The licensing agreement specifically covers the lead indication in the United States, while AB2 Bio preserves exclusive global rights for all other indications and all territories outside the U.S. for the lead program. Beyond the immediate $30 million payment, the agreement includes the potential for up to $100 million in development milestones and up to $500 million in commercial milestones and royalties, creating substantial long-term value for AB2 Bio. The transaction reflects increasing confidence in the company’s IL-18-targeted therapeutic platform and leverages Nippon Shinyaku’s established expertise in developing and commercializing therapies for rare diseases within the U.S. market.
Tadekinig Alfa Targets a Rare Life-Threatening Inflammatory Disease
Tadekinig alfa is a recombinant human interleukin-18 binding protein (IL-18BP) engineered to neutralize excess free IL-18, a key inflammatory mediator responsible for severe systemic hyperinflammation. The investigational biologic is being developed to treat Primary Monogenic IL-18-Driven Hyperinflammatory Syndrome, an ultra-rare pediatric disorder caused by NLRC4 and XIAP genetic mutations. Patients suffering from this condition experience uncontrolled inflammation that can rapidly progress to multiorgan dysfunction, irreversible organ damage, and even death. Unlike conventional supportive therapies, Tadekinig alfa is designed to directly target the underlying disease mechanism by restoring the natural balance between IL-18 and its endogenous inhibitor. The therapy has successfully completed its Phase 3 clinical program in the lead indication and has demonstrated clinical proof of concept in multiple additional orphan diseases. It has also received FDA Breakthrough Therapy, Rare Pediatric Disease, and Orphan Drug Designations, highlighting its potential to address a critical unmet medical need.
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Regulatory Progress Positions AB2 Bio for Future Growth
With AB2 Bio continuing to lead BLA preparation and regulatory interactions with the FDA, the company remains central to advancing Tadekinig alfa toward potential U.S. approval. The strengthened alliance combines AB2 Bio’s expertise in IL-18 biology with Nippon Shinyaku’s proven commercialization capabilities in rare diseases, creating a pathway for accelerated market access if regulatory approval is achieved. The collaboration also enables AB2 Bio to continue expanding Tadekinig alfa across additional IL-18-mediated inflammatory disorders, preserving significant long-term pipeline value beyond the initial indication. As demand grows for targeted therapies treating rare immune-mediated diseases, the licensing agreement underscores increasing industry confidence in precision biologics designed to address previously untreatable inflammatory conditions. The milestone positions both companies to advance innovative treatments for patients with devastating rare diseases while supporting continued investment in next-generation immunology therapeutics.
Source: AB2 Bio press release
