NEW YORK – Merck and Daiichi Sankyo said on Tuesday that they have inked a deal to codevelop and co-commercialize the delta-like ligand 3 (DLL3) T-cell engager MK-6070.
The latest agreement amends an October 2023 deal the companies inked to jointly develop and commercialize three antibody-drug conjugates (ADCs). Under the expanded deal, Merck and Daiichi Sankyo will now also jointly advance MK-6070.
Merck brought MK-6070 — formerly known as HPN328 — into its pipeline when it acquired Harpoon Therapeutics in early 2024.
Under the terms of the expanded deal with Daiichi Sankyo, Merck will receive an upfront payment of $170 million. The two drugmakers will share R&D costs, commercialization expenses, and worldwide profits. The deal excludes Japan, where Merck will retain exclusive rights to MK-6070 and Daiichi Sankyo will be eligible for royalty payments based on sales.
The firms will evaluate MK-6070 in small cell lung cancer, neuroendocrine prostate cancer, and other high-grade neuroendocrine tumor types in a Phase I/II clinical trial. Patients with small-cell lung cancer will receive MK-6070 combined with Genentech's immune checkpoint inhibitor Tecentriq (atezolizumab), whereas other patients will receive MK-6070 monotherapy.
Although patients with small cell lung and neuroendocrine prostate cancer — tumor types with high DLL3 expression — will be enrolled without prospective biomarker testing, they will still be required to provide tissue samples or fresh biopsies for retrospective biomarker evaluation. Patients with any other type of neuroendocrine cancer will need to have confirmed DLL3 positivity prior to study enrollment.
Merck and Daiichi Sankyo also plan to test MK-6070's activity in combination with other drugs, including ifinatamab deruxtecan, one of the three ADCs included in their original 2023 pact. The two companies will share profits from sales of ifinatamab deruxtecan when combined with MK-6070 in line with the terms of the 2023 deal. Merck, for its part, will generally record sales for MK-6070.