At a time when much of the biopharma space can’t seem to get enough of antibody-drug conjugates (ADC), Bristol Myers Squibb Co. is backing away from a potential $3 billion-plus collaboration with Eisai Co. Ltd., handing back full rights to the latter’s folate receptor alpha-targeting ADC, farletuzumab ecteribulin (FZEC), citing a portfolio reprioritization. Global rights to FZEC now reside with Tokyo-based Eisai, which said it intends to accelerate work on the candidate, which is in three clinical studies, including two phase II trials in gynecological cancers and non-small-cell lung cancer.