In a bid to bolster its oncology portfolio, Merck & Co. has entered into a development and commercialisation agreement with Daiichi Sankyo for three of the latter’s exatecan derivative (DXd) antibody-drug conjugate (ADC) clinical candidates for different cancers. The deal is one of the largest licensing deals to date, with a US$4 B upfront payment and the potential to reach US$22 B in total. The collaboration marks yet another move by Merck to secure a place in the growing ADC market, following its previous deals with Seagen and Kelun-Biotech.