Daiichi Sankyo and Merck have entered into a global development and commercialization agreement for three of Daiichi Sankyo’s DXd antibody-drug conjugate (ADC) candidates: patritumab deruxtecan (HER3-DXd), ifinatamab deruxtecan (I-DXd) and raludotatug deruxtecan (R-DXd), in a deal worth up to $22 billion ($4 billion upfront, $1.5 billion in continuation payments, and $16.5 billion in milestone payments).  

All three DXd ADCs 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. The submission of a biologics license application (BLA) in the US is planned by the end of March 2024 for patritumab deruxtecan.  

Ifinatamab deruxtecan is currently being evaluated as monotherapy in a Phase II clinical trial in patients with previously treated extensive-stage small cell lung cancer (SCLC). 

The companies will jointly develop and potentially commercialize these ADC candidates worldwide, except in Japan where Daiichi Sankyo will maintain exclusive rights. Daiichi Sankyo will be solely responsible for manufacturing and supply. 

Under the agreement, 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. When combined with the additional refundable upfront payment of $1 billion described below, total potential consideration across the three programs is up to $22 billion. 

Source: Merck & Co.