A Phase 1 trial shows that trastuzumab rezetecan (SHR-A1811), a next-generation antibody-drug conjugate (ADC), is effective and well-tolerated in patients with HER2-expressing gastric (GC/GEJ) and colorectal cancers (CRC).
Trastuzumab rezetecan works like a “smart bomb”: the HER2-targeting antibody directs the drug to cancer cells, while a linked chemotherapy payload is released inside tumors, limiting damage to healthy tissue.
Across 16 centers in China, the trial reported strong results even in patients who had failed prior therapies. Objective response rates were 45% in HER2+ gastric cancer and 40.5% in HER2+ colorectal cancer, with median progression-free survival of about 9–9.5 months and median overall survival of 16–23 months. HER2-low gastric cancer patients also showed a 25% response rate.
Side effects were mostly low blood counts, which were manageable. Only 2% experienced serious lung issues, much lower than with similar drugs, and just 5% discontinued treatment.The recommended dose is 6.4 mg/kg every three weeks. Phase 2 and 3 trials are planned to test an every-two-week schedule to maintain effectiveness while reducing blood-related toxicities.