Abstract 1210P
Background
KN026 is a novel bispecific antibody that simultaneously binds to two distinct HER2 epitopes. KN046 is a novel bispecific antibody that blocks both PD-L1 interaction with PD-1 and CTLA-4 interaction with CD80/CD86. An IIT study (KN046-IST-02) had proved efficacy and safety of KN026 combined with KN046 for late line HER2 positive gastrointestinal cancer.
Methods
KN026-203 study (NCT04521179) is an open-label, phase II, multi-center study to evaluate the efficacy and safety of KN026 (30mg/kg, Q3W, C1D8 loading) combined with KN046 (5mg/kg, Q3W) in patients with HER2-positive solid tumors. Patients received treatment until disease progression or unacceptable toxicity. Tumor assessments were scheduled every 6 weeks. The primary endpoint was objective response rate (ORR) and duration of response (DOR).
Results
As of 30 Jan 2022, a total of 31 HER2 positive locally advanced unresectable or metastatic gastric/gastroesophageal junction cancer (GC/GEJ) patients without prior systemic treatment were enrolled. The median age was 64 years old with 14 patients (45.2%) aged ≥ 65 years. 21 patients (67.7%) were male. 26 patients (83.9%) were HER2 IHC 3+ and the other 5 patients (16.1%) were HER2 IHC 2+ with FISH positive. 19 patients (61.3%) had liver metastasis and 4 patients (12.9%) had lung metastasis. 27 patients were evaluable for efficacy assessment. The ORR was up to 77.8% (95% CI: 57.7, 91.4), and the DCR was 92.6% (95% CI: 75.7, 99.1). Common TRAEs were diarrhea (32.3%), Pyrexia (32.3%), leukopenia (22.6%), neutropenia (16.1%), and infusion related reaction (16.1%). Most of them were Grade 1 or 2. Only 5 patients (16.1%) occurred grade ≥ 3 TRAEs, and the most common was diarrhea (6.5%). There was no treatment related death.
Conclusions
KN026 combined with KN046 treatment had demonstrated outstanding efficacy and manageable safety in HER2 positive GC/GEJ patients without prior systemic treatment. It might be deserved to plan a randomized study to compare the KN026+KN046 treatment and the standard of care to further confirm the efficacy and safety.
Clinical trial identification
NCT04521179.
Editorial acknowledgement
Legal entity responsible for the study
Alphamab Oncology.
Funding
Alphamab Oncology.
Disclosure
X. Li: Financial Interests, Personal, Full or part-time Employment: Alphamab Oncology. B. Xia: Financial Interests, Personal, Full or part-time Employment: Alphamab Oncology. All other authors have declared no conflicts of interest.