The randomized, multicenter trial, which enrolled 365 patients, demonstrated that trastuzumab botidotin nearly tripled median progression-free survival, reaching 11.1 months compared to 4.4 months for those treated with T-DM1. Beyond these primary results, the drug showed a more durable clinical response, with an objective response rate of 76.9% versus 53.0%. Researchers also noted a 38% reduction in the risk of death, though overall survival data remain immature.

Safety profiles favored the new therapy, which exhibited lower incidences of hematologic, hepatic, and gastrointestinal toxicities compared to T-DM1. While ocular events were identified as the most common side effect, investigators reported these were manageable through standardized clinical strategies. Following these findings, which were previously showcased at the 2025 ESMO Congress, China’s National Medical Products Administration granted approval for the drug as a second-line treatment for advanced HER2-positive breast cancer, marking a significant milestone for Chinese-developed oncology therapeutics.