In the latest high profile antibody drug conjugate (ADC) deal, this week Hangzhou-based Bliss Biopharmaceutical (BlissBio) announced a clinical trial collaboration agreement with Eisai for its lead ADC BB-1701, which is in Phase I/II in China and the U.S. BB-1701 has an eribulin-payload directed against Human Epidermal Growth Factor Receptor 2 (HER2) for cancer treatment. The deal, which is worth up to $2B, includes an option for strategic collaboration.
Just this spring, Pfizer, BioNTech, and BMS all dove deep into ADCs with big deals. Pfizer’s was the biggest, as the company shelled out $43B for Seagen.
BB-1701 is a potential standout because it could compete with breakout “HER2-low” drug Enhertu (from Daiichi and AstraZeneca), which was approved for that subtype of breast cancer in August 2022. It is estimated to have raked in more than $1B that year.
“This clinical collaboration with Eisai, one of a leading Japanese pharmaceutical companies with strong oncology R&D capability worldwide, is a significant accomplishment for BlissBio, as it allows us to further develop this promising compound, BB-1701”, said Ziping Wei, Chief Executive Officer of BlissBio.
The HER2-low breast cancer subtype is a newly defined subset consisting of tumors that would have previously been considered HER2-negative based on immunohistochemistry (IHC) assay and in situ hybridization (ISH) assays. These tumors express low amounts of the HER2 protein, but not enough to be considered HER2-positive.
Erbulin (Halaven), a laboratory-made form of halichondrin B, is manufactured by Eisai. It is a long-established chemotherapy in breast cancer and soft tissue sarcoma. Recently, Eisai has been investigating the treatment’s efficacy in HER2- low breast cancer.
Through this new deal, Eisai and Bliss will work together to develop BB-1701 globally. BB-1701 is currently being studied in over one hundred patients with various types of cancers.
Under the terms of the agreement, BlissBio will receive upfront and milestone payments, and BlissBio and Eisai will conduct co-development activities related to BB-1701 through an option period.
Upon Eisai’s exercise of its option to enter into a strategic collaboration license of BB-1701, BlissBio will receive an option exercise payment and be eligible for development and commercial milestone payments up to an aggregate of $2 billion, as well as royalties on sales. Upon the exercise of the option, Eisai will receive worldwide (excluding Greater China) rights to develop and commercialize the drug.
BB-1701 was designed to provide a safer and more effective treatment for patients with locally advanced/metastatic HER2 expressing solid tumors. The company reports that the compound has unique mechanism of action including potent bystander effect and immunogenic cell death activity.
BlissBio has an ADC-focused pipeline that includes BB-1701, BB-1705 (phase I for triple negative breast cancer, head and neck, non-small cell lung cancer, digestive tumors, and more), BB-1709 (Phase I for solid tumors), and several other compounds in preclinical development for solid tumors.
The company also reports it has “GMP manufacture capability that could support antibody and ADC production for both clinical development and early commercialization.”