Duality Biotherapeutics, Inc. (Duality Biotherapeutics) has formally exercised its exclusive cost and profit/loss sharing option for the antibody-drug conjugate (ADC) DB-1311/BNT324 in the United States. Written notice was delivered to BioNTech SE on 12 May 2026 (Hong Kong time), activating a key provision of the parties’ March 2023 license and collaboration agreement.

Under the agreement terms, exercising the option obliges Duality Biotherapeutics to reimburse BioNTech for its share of historical U.S. development expenses. The option becomes effective once this payment is made, after which both partners will share future development costs as well as commercialization profits or losses for the first DB-1311/BNT324 product in the U.S. market.

Management cited encouraging clinical signals and substantial commercial potential as drivers for the decision. DB-1311/BNT324, a next-generation topoisomerase-I-inhibitor ADC targeting the immune-checkpoint protein B7-H3, is currently being assessed in a Phase 1/2 trial (NCT05914116) for advanced or metastatic solid tumors. Two additional studies are evaluating the candidate in combination with an investigational PD-L1xVEGF-A bispecific immunomodulator: a Phase 2 trial (NCT06953089) across multiple solid tumors and a Phase 1/2 trial (NCT06892548) in small cell and non-small cell lung cancers.

The Board believes that assuming shared U.S. rights positions Duality Biotherapeutics to capture potential value from DB-1311/BNT324, while aligning economic interests with partner BioNTech. No assurance can be given that the product will ultimately reach commercialization.