Patients whose stomach cancer keeps growing after two or more rounds of treatment typically have few options left and survival measured in months. Gastric cancer remains one of the deadliest tumors worldwide, and Japan and China sit among the regions where it is most common. Takeda tested its experimental drug in that late-line population, in a trial run across both countries. Takeda said in data presented at the European Society for Medical Oncology congress that median overall survival was 10.2 months with arcotatug tavatecan versus 6.9 months for patients given a chemotherapy chosen by their physician, and that the drug also delayed progression and produced far more tumor responses. The comparator drugs are standard later-line treatments in this setting, making the gap more notable than a comparison against placebo would be.
The drug belongs to a class known as antibody-drug conjugates, which use an antibody to ferry a cell-killing payload directly into tumors. Its target, claudin 18.2, is a protein normally confined to the stomach lining but abundant on many gastric tumors, and it has become one of the most contested targets in gastrointestinal oncology. China's Innovent Biologics discovered the molecule and said in June that it granted Takeda exclusive rights outside greater China in October 2025, and that its own Chinese marketing application was the first for any claudin 18.2 conjugate.
Safety matters as much as efficacy for patients already weakened by prior treatment. Severe treatment-related side effects occurred in 47.4% of patients on the drug versus 55.9% on chemotherapy, with low rates of serious nausea, vomiting and diarrhea, though one treatment-related death was recorded in the drug arm, the release said. Innovent is handling the Chinese review, where regulators have granted priority status. Takeda intends to use these data to support a regulatory filing in Japan. A Japanese approval would be the drug's first outside China.