- Bristol Myers Squibb and Eisai are partnering to develop a targeted drug that could be used to treat several types of cancer, with Bristol Myers paying Eisai $650 million upfront for rights to the Japanese company's synthetic antibody linked to a chemical toxin.
- Under the terms of the deal, $200 million of the upfront fee will pay Eisai's research and development costs. Eisai would also be eligible for up to $2.5 billion in milestone payments. If successful, the partners will jointly commercialize the drug in the Asia-Pacific region, the U.S., Canada, Europe and Russia.
- The deal is a sign of Bristol Myers' interest in so-called antibody drug conjugates, or ADCs, and extends a spate of dealmaking in the space by large pharmaceutical companies. Merck & Co., AstraZeneca and Gilead have all spent billions of dollars to secure access to ADCs. Before Thursday's deal, Bristol Myers had rights to only one, via its acquisition of Celgene.
Eisai's drug binds to tumor cells that have a large number of proteins known as folate-receptor alpha on their surface. Once bound, the drug releases eribulin, which Eisai also markets as a chemotherapy called Halaven, to kill the tumor cells.
These types of drugs have become increasingly common over the past decade, despite setbacks to the first one approved, Pfizer's Mylotarg. The drug was removed from the market for seven years because of side effects before being reintroduced at a lower dose.
SeaGen, the Bothell, Washington-based drugmaker, has since paved the way for biotechs interested in ADCs. Its medicine Adcetris gained approval as a treatment for certain blood cancers in 2011, and has helped rekindle big pharma's interest. Eleven ADCs are now on the market.
Merck's become one of the major players in the space, paying nearly $3 billion to acquire ADC specialist VelosBio and spending another $1.7 billion to get rights to two SeaGen drugs. Gilead, meanwhile, bought Immunomedics and its approved ADC for breast cancer, Trodelvy, for $21 billion, marking the largest acquisition in the company's history.
AstraZeneca has also shelled out more than $2 billion on an ADC-focused partnership with Japan's Daiichi Sankyo.
Eisai's drug is currently in the early stages of human testing in Japan and the U.S., where researchers are evaluating it in solid tumors positive for folate receptor-alpha, which include endometrial, ovarian, lung and breast cancers. In a statement, the companies said next year they plan to begin late-stage trials that could be used to support approval.
The drug has some catching up to do, though. An experimental folate receptor-targeting medicine developed by the biotech Immunogen has advanced to late-stage testing for ovarian cancer. If the first of these trials is successful, Immunogen believes it will be able to file for accelerated approval in 2022.
A small biotech called Sutro Biopharma also has a folate receptor-targeting ADC in Phase 1 trials.