AB2 Bio will receive $30 million from Nippon Shinyaku after the Japanese pharmaceutical company exercised its option to commercialise Tadekinig alfa in the US for an ultra-rare paediatric inflammatory disease.

The option exercise gives Nippon Shinyaku exclusive US commercialisation rights for Tadekinig alfa in Primary Monogenic IL-18-Driven Hyperinflammatory Syndrome in patients with NLRC4 and XIAP mutations.

AB2 Bio retains worldwide rights to Tadekinig alfa for other indications and rights outside the US for the lead indication. The company will also continue to lead preparation of the Biologics License Application (BLA) and other US regulatory activities.

Under the agreement, AB2 Bio will receive a $30 million option exercise payment and is eligible for up to $100 million in development milestones and up to $500 million in commercial milestones and royalties.

The deal builds on a 2025 option and licence agreement between the companies, under which AB2 Bio previously received a $6 million option fee.

The transaction may require clearance under the Hart-Scott-Rodino Antitrust Improvements Act, depending on the circumstances at the time of exercise.

Tadekinig alfa targets IL-18-driven hyperinflammation

Tadekinig alfa is a recombinant human interleukin-18 binding protein designed to neutralise excess free IL-18, a protein involved in driving severe inflammation.

The lead indication is an ultra-rare, potentially life-threatening condition primarily affecting infants and young children with mutations in the NLRC4 or XIAP genes.

Patients can develop severe systemic hyperinflammation, which may progress to multiorgan dysfunction and irreversible organ damage.

AB2 Bio said there are currently no FDA-approved treatments for the condition.

The company’s Phase 3 clinical programme enrolled patients with genetically confirmed NLRC4 or XIAP mutations who continued to experience severe hyperinflammation despite standard supportive care.

Djordje Filipovic, CEO of AB2 Bio, said: “This progress represents an important milestone for AB2 Bio and, more importantly, for patients and families affected by this devastating disease.”

The company said Tadekinig alfa is designed to target the underlying mechanism driving the disease by neutralising excess free IL-18, rather than treating the resulting symptoms.

Nippon Shinyaku takes US commercialisation rights

Nippon Shinyaku’s option exercise gives the company exclusive commercialisation rights in the US for the lead indication.

AB2 Bio retains rights to Tadekinig alfa for all other indications in the US and for all indications outside the US.

The company has also completed its Phase 3 clinical programme in the lead indication and has reported clinical proof of concept in three additional life-threatening orphan diseases, according to the company.

Tadekinig alfa has received Orphan Drug Designation in the US and Europe, as well as Breakthrough Therapy and Rare Pediatric Disease Designations from the FDA.

The Rare Pediatric Disease Designation could make the therapy eligible for a Priority Review Voucher if it is ultimately approved and meets the relevant regulatory requirements.

Toru Nakai, president and representative director of Nippon Shinyaku, said: “There are currently no FDA-approved therapies for this rare and potentially life-threatening disease.”

Nippon Shinyaku said the expanded partnership with AB2 Bio would support efforts to bring Tadekinig alfa to patients in the US.

AB2 Bio retains global development rights

The agreement allows AB2 Bio to retain significant rights to Tadekinig alfa beyond the US lead indication.

The company continues to develop the therapy for additional IL-18-driven inflammatory diseases, while Nippon Shinyaku will take responsibility for US commercialisation of the lead indication following regulatory approval.

AB2 Bio said the potential value of the agreement includes up to $100 million in development milestone payments and up to $500 million in commercial milestone and royalty payments, in addition to the $30 million option exercise payment.

The company will continue to lead the BLA preparation and US regulatory activities for Tadekinig alfa.

The deal comes as biopharmaceutical companies continue to pursue targeted treatments for ultra-rare diseases where conventional approaches may not address the underlying biological drivers of disease.

For AB2 Bio, the agreement provides non-dilutive funding and a commercialisation partner for the US market while allowing the company to retain rights to Tadekinig alfa across other indications and territories.