On December 10, 2025 Akeso, Inc. (9926.HK) ("Akeso" or the "Company") reported the presentation of a Phase II clinical study that included a longer-term efficacy data evaluating ivonescimab (a PD-1/VEGF bispecific antibody) combined with chemotherapy as a first-line treatment for locally advanced unresectable or metastatic triple-negative breast cancer (TNBC) at the 2025 European Society for Medical Oncology Immuno-Oncology Congress (ESMO IO) in London, UK.

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Based on positive efficacy and safety profile, the ivonescimab combination therapy for first-line TNBC was previously included in the Breakthrough Therapy Designation (BTD) list by the Center for Drug Evaluation (CDE) of China’s National Medical Products Administration (NMPA). Currently, the multicenter, randomized, double-blind Phase III clinical trial (HARMONi-BC1/AK112-308) for this indication is currently ongoing.

Preliminary results from this study were previously announced at the European Society for Medical Oncology (ESMO) (Free ESMO Whitepaper) Congress 2024 and the 2024 San Antonio Breast Cancer Symposium (SABCS). With the follow-up period now extended to 22.1 months, the study further validates the efficacy and safety profile of the ivonescimab regimen in first-line TNBC treatment.

As of July 15, 2025, a total of 36 patients with TNBC were enrolled. The median age was 55 years, 83.3% of patients had a PD-L1 combined positive score (CPS) <10, and 55.6% had received prior taxane-based neo/adjuvant therapy. As of the data cutoff, 35 patients had undergone at least one post-baseline tumor assessment and were included in the efficacy analysis set. The results showed that the ivonescimab combined with chemotherapy regimen demonstrated efficient tumor relief, disease control, and survival benefits in all PD-L1 subgroups of TNBC patients receiving first-line treatment. The key results are:

The objective response rate (ORR) for the overall population was 80.0%, the disease control rate (DCR) was 100.0%, and the median duration of response (mDOR) was 12.2 months; the median progression-free survival (mPFS) was 15.2 months, with a 12-month PFS rate of 56.3%.
In the CPS≥10 subgroup, the ORR was 83.3%, the DCR was 100%, the mDOR was 12.2 months; the mPFS was 15.9 months, with a 12-month PFS rate of 66.7%.
In the CPS<10 subgroup, the ORR was 79.3%, the DCR was 100%, the mDOR was 9.9 months; the mPFS was 13.04 months, with a 12-month PFS rate of 54.3%.
In the CPS≥1 subgroup, the ORR was 72.2%, the DCR was 100%, the mDOR was 12.2 months; the mPFS was 15.9 months, with a 12-month PFS rate of 63.8%.
Overall survival (OS) data is not yet mature.
Ivonescimab combined with chemotherapy as first-line treatment for TNBC demonstrated a good safety profile. No treatment-related adverse events (TRAEs) led to discontinuation or death in this study, and the most common TRAEs were mostly grade 1-2.

(Press release, Akeso Biopharma, DEC 10, 2025, View Source [SID1234661352])