In a $4B upfront deal, Merck is acquiring three of Daiichi Sankyo’s antibody-drug conjugate (ADC) candidates: patritumab deruxtecan (HER3-DXd), ifinatamab deruxtecan (I-DXd), and raludotatug deruxtecan (R-DXd). The two companies will jointly develop and commercialize these drugs worldwide, except in Japan where Daiichi Sankyo will maintain exclusive rights. Total potential consideration across the three programs is up to $22 billion.
Daiichi Sankyo is one of the leaders in the ADC field, which is estimated to be worth about $6B already. This is the latest, and the biggest, in a series of big ADC deals.
All three of the ADCs in this deal are in various stages of clinical development for the treatment of multiple solid tumors both as monotherapy and/or in combination with other treatments.
Patritumab deruxtecan was granted Breakthrough Therapy Designation by the US Food and Drug Administration in December 2021 for the treatment of patients with EGFR-mutated locally advanced or metastatic non-small cell lung cancer (NSCLC) with disease progression on or after treatment with a third-generation tyrosine kinase inhibitor (TKI) and platinum-based therapies.
Ifinatamab deruxtecan is being evaluated as monotherapy in IDeate-01 (ClinicalTrials.gov; NCT05280470), a Phase II clinical trial in patients with previously treated extensive-stage small cell lung cancer (SCLC). Updated results from a subgroup analysis of a Phase I/II trial of ifinatamab deruxtecan in SCLC were recently presented at the IASLC 2023 World Conference on Lung Cancer.
Raludotatug deruxtecan is being evaluated in a first-in-human Phase 1 clinical trial and updated results in patients with advanced ovarian cancer were presented at the this year’s European Society for Medical Oncology (ESMO) Congress.
Merck will pay Daiichi Sankyo upfront payments of $1.5 billion for ifinatamab deruxtecan due upon execution; $1.5 billion for patritumab deruxtecan, where $750 million is due upon execution and $750 million is due after 12 months; and $1.5 billion for raludotatug deruxtecan, where $750 million is due upon execution and $750 million is due after 24 months.
Merck also will pay Daiichi Sankyo up to an additional $5.5 billion for each DXd ADC contingent upon the achievement of certain sales milestones,
Daiichi Sankyo’s proprietary DXd ADC technology aims to target and deliver a cytotoxic payload inside cancer cells that expresses a specific cell surface antigen. Each ADC consists of a monoclonal antibody attached to a number of topoisomerase I inhibitor payloads (an exatecan derivative, DXd) via tetrapeptide-based cleavable linkers.
“The promising results from clinical trials of patritumab deruxtecan, ifinatamab deruxtecan and raludotatug deruxtecan continue to demonstrate the broad applicability of Daiichi Sankyo’s DXd ADC technology across multiple targets, with each of these medicines having the potential to change clinical practice as has been already seen with ENHERTU,” said Sunao Manabe, representative director, executive chairperson and CEO, Daiichi Sankyo Company, Limited.
“At Merck, we continue to augment and diversify our oncology pipeline while building on our immuno-oncology foundation,” said Robert M. Davis, Chairman and Chief Executive Officer, Merck. “The pioneering work by Daiichi Sankyo scientists has highlighted the far-reaching potential of ADCs to provide meaningful new options for patients with cancer. We look forward to forging this collaboration to deliver the next generation of precision cancer medicines, driven by our mutual compassion for patients around the world.”
Daiichi Sankyo’s ADC portfolio currently consists of six ADCs in clinical development across multiple types of cancer. The company’s proprietary DXd ADC technology is designed to target and deliver a cytotoxic payload inside cancer cells that express a specific cell surface antigen, each ADC consists of a monoclonal antibody attached to a number of topoisomerase I inhibitor payloads (an exatecan derivative, DXd) via tetrapeptide-based cleavable linkers.
