MRK, Daiichi Begin Pivotal Esophageal Cancer Study With ADC Drug

Core Insights - Merck and Daiichi Sankyo have initiated the phase III IDeate-Esophageal01 study for the B7-H3 directed ADC, ifinatamab deruxtecan (I-DXd), targeting advanced or metastatic esophageal squamous cell carcinoma (ESCC) patients [1][2] - The study aims to compare the safety and efficacy of I-DXd against an investigator's choice of chemotherapy in patients who have progressed after platinum-based therapy and immune checkpoint inhibitors [2] - The primary endpoint is overall survival, with secondary endpoints including progression-free survival and objective response rate [3] Company Developments - Merck's stock has decreased by 22.3% year-to-date, while the industry has seen a decline of 5.2% [6] - Merck acquired global co-development and co-commercialization rights for I-DXd and two other ADCs from Daiichi Sankyo for a potential total of up to $22 billion, retaining exclusive rights for Daiichi in Japan [8] - Merck has expanded its collaboration with Daiichi to co-develop MK-6070, a T-cell engager targeting DLL3, following its acquisition of Harpoon Therapeutics [9] Industry Context - ADCs are viewed as a disruptive innovation in the pharmaceutical industry, enhancing cancer treatment by using antibodies to deliver cytotoxic drugs directly to tumors [11] - Daiichi Sankyo is developing several ADCs across various cancer types, including Enhertu, which is marketed in partnership with AstraZeneca [12] - Pfizer has entered the ADC market by acquiring Seagen for $43 billion, adding three ADCs to its portfolio that have significantly contributed to its revenues in 2024 [13][14]