#China #Chengdu #Kelun-Biotech #ESMO 2025 #Trastuzumab Botidotin

Promising Phase 3 Results for Trastuzumab Botidotin

At the 2025 European Society for Medical Oncology (ESMO) Congress held in Berlin, Germany, Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. made headlines with the presentation of Phase 3 clinical trial results for their innovative HER2-targeted antibody-drug conjugate (ADC), Trastuzumab Botidotin, also known as A166. Leading oncologist Professor Xichun Hu from Fudan University Shanghai Cancer Center provided insights into the study, which evaluated the efficacy of Trastuzumab Botidotin in comparison to Trastuzumab Emtansine (T-DM1) for patients diagnosed with unresectable or metastatic breast cancer that expresses the HER2 marker.

The Study Overview

The study included 365 patients who had previously undergone at least one anti-HER2 therapy. Of these participants, a significant number—53%—had been treated with two or more lines of anti-HER2 therapies, while 61% exhibited a HER2 immunohistochemistry (IHC) score of 3+. Importantly, 60% of the patients had experience with Tyrosine Kinase Inhibitors (TKIs), such as Pyrotinib. With a median follow-up period of 14.9 months as of April 26, 2025, the results highlighted the comparative benefits of Trastuzumab Botidotin in managing this challenging subset of breast cancer patients.

Efficacy and Safety Outcomes

The progression-free survival (PFS) was substantially better in the Trastuzumab Botidotin group compared to T-DM1, reporting a median PFS of 11.1 months versus 4.4 months respectively—yielding a hazard ratio (HR) of 0.39 (95% CI, 0.30-0.51, p<0.0001). This pattern of beneficial outcomes was consistent across all prior lines of anti-HER2 therapies. The trial also revealed an impressive overall response rate (ORR) of 76.9% for Trastuzumab Botidotin against 53.0% for T-DM1 in blinded central reviews. Additional trends suggested improved overall survival with Trastuzumab Botidotin as well (HR 0.62; 95% CI, 0.38-1.03).

Both treatment options presented challenges in terms of grade 3 or higher treatment-emergent adverse events (TEAEs), with 69.8% of patients on Trastuzumab Botidotin experiencing significant symptoms compared to 63.7% with T-DM1. Notably, ocular adverse events led to the most dose reductions within the Trastuzumab Botidotin cohort. Importantly, only two patients permanently ceased treatment due to TEAEs, and there were no on-treatment deaths reported in the Trastuzumab Botidotin group, while T-DM1 had a 1.6% mortality rate, all unrelated to the treatment.

Implications for Future Treatment

The presented findings underscore Trastuzumab Botidotin's potential to provide meaningful treatment advancements for patients who have become resistant to other options. As Professor Hu stated, “Trastuzumab Botidotin demonstrates an effective balance of safety and efficacy through its unique molecular design.” This design aims to mitigate risks of complications such as interstitial lung disease and hematologic toxicity, which are critical considerations in treating sensitive patient groups.

The excitement surrounding these findings is matched only by the anticipation they evoke for clinicians and patients alike, who have long sought new, viable treatment avenues. As Kelun-Biotech continues its progress with Trastuzumab Botidotin, including an ongoing Phase 2 clinical trial targeting HER2-positive breast cancers previously treated with topoisomerase inhibitors, the future looks bright for enhancing personalized treatment protocols in oncology.

About Kelun-Biotech

Kelun-Biotech is not just a player in the pharmaceutical arena; it represents a commitment to addressing significant healthcare needs globally. As a subsidiary of Kelun Pharmaceutical, their innovative biological drugs and commitment to research and development focus primarily on solid tumors, autoimmune diseases, and metabolic disorders. With a robust pipeline of over 30 innovative drug projects and several already approved for market launch, Kelun-Biotech aims to redefine the landscape of treatment options available for cancer and beyond. Further details on their projects and innovations can be accessed through their website at https://kelun-biotech.com.