In the latest deal from the burgeoning antibody-drug conjugate (ADC) space, Eisai Co. Ltd. and privately held Bliss Biopharmaceutical (Hangzhou) Co. Ltd. reached a development and commercialization agreement that could be worth up to $2 billion. The massive collaboration is the eighth largest so far this year and one of three that involve ADCs in the year’s top 10 deals. The year’s biggest, according to BioWorld statistics, is the partnership extension between Evotec SE and Bristol Myers Squibb Co. to identify neurodegenerative disease therapies for eight years. The other ADC deals involve Synaffix BV, which signed a $2 billion pact in January with Amgen Inc., and a $2.2 billion expanded deal in February with Macrogenics Inc.