Abstract 1377P
Background
The study assessing the safety, tolerability and preliminary efficacy for KN026 in combination with KN046 in pts with HER2 aberrated solid tumors was reported in the Society for Immunotherapy of Cancer 2020. Here we reported the efficacy and safety in pts with HER2-positive gastrointestinal tumors from expansion phase.
Methods
Chinese pts with HER2-positive gastrointestinal tumors were enrolled and received combination of KN026 and KN046 at three doses (DL1: KN026 20 mg/kg Q2W + KN046 3 mg/kg Q2W; DL2: KN026 20 mg/kg Q2W with loading on Days 1, 8 of Cycle 1 + KN046 5 mg/kg Q3W; DL3: KN026 30 mg/kg Q3W with loading on Days 1, 8 of Cycle 1 + KN046 5 mg/kg Q3W). Tumor response was evaluated Q8W per RECIST 1.1.
Results
At the time of data cutoff (12-January-2021), 19 (59%) of the 32 pts (treatment naïve mGC/GEJ 7 pts; heavily pretreated GI cancer 25 pts) enrolled were still ongoing on study treatment. The median treatment durations of KN026 and KN046 exposure were 17 weeks (4∼60 weeks) and 15 weeks (4∼58 weeks) respectively. Among 25 efficacy evaluable pts, ORR was 86% (6/7, 95% CI: 42%-100%) in the first-line mGC/GEJ cohort.ORR in the late line GI cancer cohort was 44% (8/18, 95% CI: 22%-69%). Median PFS was 5.8 months (mo). 6- and 12-month OS rates were 89.1% and 71.3%. In the late line GC/GEJ cohort, mPFS was 8.4 mo and 12-month OS rates were 91.7%. Common related AEs (≥ 15%) were anaemia (31%), diarrhea (28%), blood bilirubin increased (25%), AST increased (22%), platelet count decreased (19%), white blood cell count decreased (19%) and ALT increased (16%). Grade ≥3 related AEs were neutrophil count decreased (3.1%), platelet count decreased (3.1%), immune-mediated endocrinopathy (3.1%), encephalitis (3.1%), infusion related reaction (3.1%) and pulmonary arterial hypertension (3.1%).
Conclusions
KN026 combined with KN046 as a chemo-free regimen was safe and demonstrated potential superior clinical benefit to available standard of care in both treatment-naïve and heavily pretreated HER2-postive gastrointestinal tumors. Pivotal trials in HER2-positive GC/GEJ are planned.
Clinical trial identification
NCT04040699.
Editorial acknowledgement
Legal entity responsible for the study
Beijing Cancer Hospital, Beijing, China/Henan Cancer Hospital, Zhengzhou, China/Jiangsu Alphamab Biopharmaceuticals Co.,Ltd.
Funding
Jiangsu Alphamab Biopharmaceuticals Co.,Ltd.
Disclosure
All authors have declared no conflicts of interest.