Daiichi Sankyo and MSD have broadened their partnership for the global joint development and commercialisation of three DXd-based antibody-drug conjugates (ADCs).

DXd is Daiichi Sankyo's proprietary ADC technology platform. The deal will include MSD’s delta-like ligand 3 (DLL3) targeting T-cell engager, MK-6070.

MK-6070 was acquired by MSD through its purchase of Harpoon Therapeutics.

This asset is being assessed in a Phase I/II clinical trial for its potential in treating small cell lung cancer (SCLC) and neuroendocrine tumours.

The parties will collaborate to jointly develop and commercialise MK-6070 globally, except in Japan where MSD will hold exclusive rights.

MSD will exclusively manufacture and supply MK-6070.

The companies plan to explore the potential of MK-6070 in combination with ifinatamab deruxtecan (I-DXd) in certain SCLC patients, as well as other possible combinations.

MSD will receive $170m as an upfront payment and has fulfilled a contingent payment obligation from the original deal.

The two companies will evenly split research and development (R&D) costs, as well as profits from the global sales of MK-6070, excluding Japan, and Daiichi Sankyo will earn sales-based royalties.

R&D expenses for MK-6070 in combination with ifinatamab deruxtecan will be shared according to the terms set in the original agreement.

The expanded collaboration builds on an existing partnership initiated in October 2023, where Daiichi Sankyo and MSD agreed to jointly develop and commercialise three investigational DXd antibody-drug conjugates.

These assets are patritumab deruxtecan (HER3-DXd), ifinatamab deruxtecan (I-DXd) and raludotatug deruxtecan (R-DXd), with Daiichi Sankyo retaining exclusive rights in Japan.

Daiichi Sankyo R&D global head Ken Takeshita stated: “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.

“We look forward to continuing our relationship with Merck with the addition of MK-6070 as it provides potential synergies with our established antibody-drug conjugate collaboration, particularly ifinatamab deruxtecan, and demonstrates our shared commitment to advancing new medicines for patients.”