Eisai Co., Ltd. entered into a joint development agreement with Bliss Biopharmaceutical  Co., Ltd., for BB-1701, an antibody-drug conjugate (ADC) with option rights for a strategic collaboration.

BB-1701 is an ADC that is composed of Eisai’s in-house developed anticancer agent eribulin, and anti-HER2 antibody using a linker, and is expected to have anti-tumor effects on breast, lung and other solid tumors that express HER2. The linker-payload, which uses eribulin as a payload, is a technology platform developed by Eisai’s U.S. research base Exton Site, and Eisai is investigating the possibilities of using this platform to link to various antibodies.

Under a license agreement signed in 2018, Eisai has granted BlissBio global exclusive development rights for several ADCs to use eribulin as the payload. Based on the status of the Phase I/II trials of BB-1701 currently being conducted by BlissBio, both companies have decided to co-develop this drug.

Under the terms of the joint development agreement, Eisai will make upfront and development milestone payments to BlissBio, conduct a Phase II clinical trial in breast cancer, and obtain option rights to develop and commercialize BB-1701 globally, excluding Greater China (China, Hong Kong, Macau, Taiwan).

If Eisai exercises the option rights, an additional upfront payment will be made to BlissBio, as well as development and regulatory milestone payments, sales milestone payments and certain royalties on sales of BB-1701. If all development, regulatory and sales milestones are achieved, up to a total of $2 billion will be paid.

“BB-1701 is characterized by its payload of eribulin, which is a product of our modern synthetic organic chemistry that has already made contributions to patients with breast cancer and soft tissue sarcoma,” said, Takashi Owa, chief scientific officer, senior vice president, Eisai Co., Ltd. “Our collaboration with BlissBio will accelerate the development of BB-1701 with the goal of bringing a new treatment option to patients globally.”