Merck expands ADC partnership with Daiichi Sankyo in a $170m deal

The firms will co-commercialize the products globally, except for MK-6070 in Japan where Merck (known as MSD outside of the US and Canada) will retain the exclusive rights. Merck will also be solely responsible for the manufacture and supply of MK-6070, an investigational delta-like ligand 3 (DLL3) targeting T-cell engager.

In October 2023, Merck signed a partnership agreement with the Japanese firm to co-develop Daiichi Sankyo's patritumab deruxtecan (HER3-DXd), ifinatamab deruxtecan (I-DXd) and raludotatug deruxtecan (R-DXd) – three ADC candidates in Phase III, Phase I/II, and Phase I clinical trials, respectively. Under the agreement, Merck paid $4 billion upfront, with an additional $1.5 billion in contingency payments over the next two years.

“We look forward to further evaluating MK-6070 as monotherapy and in combination with ifinatamab deruxtecan, as well as other potential combinations. Expanding our oncology pipeline with a DLL3 T-cell engager further supports Daiichi Sankyo’s strategy to create new standards of care for patients with cancer worldwide,” a spokesperson for Daiichi Sankyo told BioProcess Insider.

MK-6070 is being evaluated as a monotherapy in a Phase I/II clinical trial (NCT04471727) in patients with advanced cancers associated with expression of DLL3. The study is also evaluating MK-6070 in combination with atezolizumab in patients with small cell lung cancer (SCLC).

DLL3 is a target relevant for 80% to 96% of SCLC and highly expressed in neuroendocrine prostate cancer and other neuroendocrine neoplasms. Merck gained MK-6070 through the acquisition of Harpoon Therapeutics in a deal worth $680 million in January 2024.

“Daiichi Sankyo looks forward to continuing our relationship with Merck with the addition of MK-6070 as it provides potential synergies with our established ADC collaboration, particularly ifinatamab deruxtecan, and demonstrates our shared commitment to advancing new medicines for patients,” the spokesperson added.