BB-1701 has survived Eisai’s decision not to option the HER2-directed antibody-drug conjugate. Weeks after Eisai quietly made its choice, its liquid biopsy partner has revealed Bliss Biopharmaceutical plans to progress the program independently.
Eisai agreed to pay BlissBio up to $2 billion to secure an option on BB-1701 in 2023. By then, AstraZeneca and cancer drug partner Daiichi Sankyo had already validated the blockbuster potential of HER2-directed ADCs with Enhertu. But Eisai identified BB-1701 as a potential best-in-class molecule, citing its eribulin-based payload-linker technology as a differentiator that could enable the ADC to carve out a niche in the HER2 space.
The partners went on to report responses in solid tumors, including in breast cancer patients who had previously received another anti-HER2 ADC. Yet, last month, Eisai revealed (PDF) it had decided not to exercise its BB-1701 option. The Japanese drugmaker recorded an impairment loss tied to the decision.
Eisai’s decision had implications for Angle, a liquid biopsy company that provided circulating tumor cell analysis to a phase 2 trial of BB-1701. Friday, Angle said the trial showed its assay can measure changes in HER2 status over time, potentially giving the test an advantage over tissue-based assessments.
Angle said the full phase 2 study of BB-1701 is ongoing and the drug efficacy results are unknown. Eisai has tapped out before seeing the results, but Angle said BlissBio has confirmed its intention to progress the ADC independently. The diagnostic company is now seeking to work with BlissBio on the next stage of BB-1701 development. Eisai will continue to work with BlissBio as a licensor for the eribulin payload.
The changes leave China’s BlissBio without a global partner for BB-1701. BlissBio faces competition in its home market from a clutch of local companies such as Duality Biologics, GeneQuantum Healthcare and Jiangsu HengRui Medicine. BioNTech licensed ex-China rights to DualityBio’s candidate in 2023. Johnson & Johnson picked up a HER2-directed ADC in its $2 billion takeover of Ambrx last year.