On June 4 local time, Innovent Biologics announced that its pivotal Phase III clinical trial of IBI343 (generic name arcotatug tavatecan, Takeda code name TAK-921), a CLDN18.2-targeted ADC drug developed in deep collaboration with Takeda Pharmaceutical, has met its primary endpoint.
An arrow incrementally going up stairs before pointing straight up. Blue backgroundMeanwhile, China's National Medical Products Administration (NMPA) has formally accepted IBI343's marketing application and included it in the priority review process , making it the world's first CLDN18.2-targeted ADC to enter the regulatory review stage . Just one year after Takeda acquired the overseas rights to the drug for $1.2 billion last year, Innovent has once again solidified its leading position in the global ADC field with solid clinical data.
I. Key results of Phase III clinical trial: Excellent efficacy and manageable safety.
The Phase III clinical trial announced this time is an international multicenter study covering China and Japan, which enrolled a total of 464 patients with locally advanced unresectable or metastatic CLDN18.2-positive gastric or gastroesophageal junction adenocarcinoma. All subjects had received at least two lines of systemic therapy.
The trial results showed that, compared with the standard chemotherapy regimen chosen by the investigators, the IBI343 treatment group achieved a statistically significant prolongation of progression-free survival (PFS) , successfully meeting the trial's pre-specified primary endpoint. Clinical experts involved in the study rated its efficacy as "excellent" in a press release, while also noting the drug's good safety and tolerability , and a low incidence of gastrointestinal toxicity.
It is worth noting that Cinda has not yet disclosed specific PFS values, overall survival (OS) data, and detailed adverse event rates. The company stated that complete data will be officially published in subsequent international academic conferences or authoritative journals.
II. $1.2 billion in transnational cooperation landed, with global development progressing simultaneously.
The global development of IBI343 adopted a typical model of "China-led + multinational pharmaceutical company cooperation". In 2025, Takeda Pharmaceutical and Innovent Biologics entered into a major collaboration, with Takeda paying an upfront payment and milestone payments of US$1.2 billion to acquire exclusive rights to IBI343 and another bispecific antibody drug, IBI363, outside of China . Innovent Biologics, on the other hand, retained all rights to IBI343 in Greater China.
The successful Phase III trial and NMPA priority review not only pave the way for IBI343's initial launch in Greater China but also provide a strong boost to Takeda's global development efforts. Currently, clinical trials of IBI343 for first-line gastric and pancreatic cancer are progressing globally, potentially further expanding its indications.
III. The global CLDN18.2 market is fiercely competitive, with Cinda leading the first tier of ADCs.
CLDN18.2, as one of the most promising targets in the field of gastric cancer, has become a fiercely contested area for global pharmaceutical companies in recent years. In 2024, Astellas' CLDN18.2 monoclonal antibody was the first to receive FDA approval, becoming the first drug to market targeting this target. However, the industry generally believes that novel therapies such as ADCs and bispecific antibodies will bring better treatment effects, so major pharmaceutical companies are increasing their investment in this area.
AstraZeneca: In 2022, it licensed a CLDN18.2 bispecific antibody, and in 2023, it reached another ADC collaboration.
Astellas: Following the launch of its monoclonal antibody, it acquired a CLDN18.2 ADC in 2025 to solidify its leading position.
Moderna: Officially entered the field in 2023
Merck: It obtained a CLDN18.2 ADC through a collaboration with Kolen Biotech, but returned the rights in 2024.
Amidst fierce competition, Innovent Biologics has temporarily secured a leading global position in the CLDN18.2 ADC track thanks to the successful Phase III trial and priority review of IBI343, and is expected to become the first approved ADC drug in this field.
IV. Industry Significance: Another Milestone Achieved in China's ADC Technology, Ushering in New Hope for Gastric Cancer Treatment
The success of IBI343 is of great significance to China's innovative drug industry and to gastric cancer patients worldwide. On the one hand, this is another milestone for Chinese pharmaceutical companies in the field of ADCs (Advanced Drug Delivery Systems) targeting popular targets globally, once again demonstrating the global competitiveness of Chinese biotech in innovative drug development. On the other hand, gastric cancer is a highly prevalent malignant tumor worldwide, especially in China, where patients with advanced gastric cancer have very limited second-line treatment options. The approval of IBI343 will provide these patients with a completely new treatment plan.

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