Akeso Unveils Promising Phase II Efficacy Data for Ivonescimab in TNBC Treatment at ESMO IO 2025

Akeso, Inc., a notable player in the biopharmaceutical sector, has recently shared noteworthy findings from a Phase II clinical trial involving ivonescimab, a novel PD-1/VEGF bispecific antibody, combined with chemotherapy as a first-line intervention for locally advanced and unresectable metastatic triple-negative breast cancer (TNBC). This research was presented at the prestigious European Society for Medical Oncology Immuno-Oncology Congress (ESMO IO) in London, marking a significant stride in the ongoing fight against this aggressive breast cancer subtype.

Previously, the combination therapy of ivonescimab and chemotherapy garnered Breakthrough Therapy Designation (BTD) from China's National Medical Products Administration (NMPA), reflecting its positive safety and efficacy profile. The momentum continues with the ongoing multicenter, randomized, double-blind Phase III clinical trial, known as HARMONi-BC1/AK112-308, which aims to further validate this promising treatment approach.

The findings presented at ESMO IO 2025 follow earlier results disclosed at the ESMO Congress 2024 and the 2024 San Antonio Breast Cancer Symposium, building upon an extended follow-up period of 22.1 months in this study. Akeso maintains a focus on the efficacy and safety of ivonescimab in treating TNBC patients, and the results suggest robust therapeutic benefits.

As of July 15, 2025, 36 patients participated in the study, predominantly women with a median age of 55 years. Notably, over 80% of these participants had a PD-L1 combined positive score (CPS) of less than 10, and around 56% had received taxane-based neoadjuvant or adjuvant therapies prior to enrolment. With 35 patients having undergone at least one tumor assessment post-baseline, the investigation revealed that the combination therapy of ivonescimab and chemotherapy yielded exceptional tumor response, consistent disease control, and notable survival advantages across various PD-L1 subgroups of TNBC patients on first-line treatment.

Key outcomes from this study included an impressive objective response rate (ORR) of 80.0% for the overall patient population, and a striking disease control rate (DCR) of 100.0%. The median duration of response (mDOR) stood at 12.2 months, complemented by a median progression-free survival (mPFS) of 15.2 months, with a 12-month PFS rate of 56.3%.

Delving further into the data, the results for the CPS≥10 subgroup indicated an ORR of 83.3%, DCR of 100%, and similar mDOR and mPFS outcomes as the overall population. Conversely, those in the CPS<10 subgroup displayed an ORR of 79.3%, sustaining the DCR at 100%, while the mDOR and mPFS illustrated slightly lower values of 9.9 months and 13.04 months respectively, with a 12-month PFS rate of 54.3%. Importantly, the group with CPS≥1 showed an ORR of 72.2% with mDOR at 12.2 months and a mPFS of 15.9 months, achieving a 63.8% PFS rate at the one-year mark. However, the overall survival (OS) data is still awaited as it has not matured yet.

In terms of safety, ivonescimab combined with chemotherapy showcased a favorable profile with no treatment-related adverse events (TRAEs) causing discontinuation or fatalities during the study. The TRAEs recorded were predominantly categorized as grade 1-2, indicating that the regimen is manageable and well-tolerated by patients.

These promising results highlight the potential of ivonescimab as a viable first-line treatment option for TNBC, a cancer subtype known for its aggressive nature and poor prognosis. Akeso’s dedication to expanding treatment options and improving patient outcomes reflects the company's commitment to innovative biopharmaceutical solutions.

Conclusion

As the clinical trial progresses, it will be pivotal to monitor the ongoing therapy effectiveness and safety to ensure that ivonescimab can provide sustained benefits. The journey towards enhancing TNBC treatment continues, with Akeso leading the charge through rigorous research and unwavering innovation.