Japan-based pharma firm Daiichi Sankyo and global life sciences company Merck, known as MSD outside of the United States and Canada, have expanded their existing global co-development and co-commercialisation agreement for three investigational DXd antibody drug conjugates to include Merck’s MK-6070, an investigational delta-like ligand 3 (DLL3) targeting T-cell engager.

The companies will jointly develop and commercialise MK-6070 worldwide, except in Japan where Merck will maintain exclusive rights. Merck will be solely responsible for manufacturing and supply for MK-6070.

MK-6070 is a T-cell engager targeting DLL3, an inhibitory canonical Notch ligand that is expressed at high levels in small cell lung cancer (SCLC) and neuroendocrine tumors, currently being evaluated in a phase 1/2 clinical trial. The companies are planning to evaluate MK-6070 in combination with ifinatamab deruxtecan (I-DXd) in certain patients with SCLC, as well as other potential combinations. Merck obtained MK-6070 through its acquisition of Harpoon Therapeutics.

Under the terms of the agreement, Merck will receive an upfront cash payment of $170 million and has also satisfied a contingent quid obligation from the original collaboration agreement. The companies will share R&D and commercialisation expenses as well as profits worldwide, except for Japan where Merck retains exclusive rights and Daiichi Sankyo receives a royalty based on sales.

R&D expenses related to MK-6070 in combination with ifinatamab deruxtecan will be shared in a manner consistent with the original agreement for ifinatamab deruxtecan. Merck will generally record sales for MK-6070 worldwide.