Trastuzumab Combined with Irinotecan in Patients with HER2-Positive Metastatic Colorectal Cancer: A Phase II Single-Arm Study and Exploratory Biomarker Analysis
- Author:
Ting XU
1
;
Xicheng WANG
;
Ying XIN
;
Zhenghang WANG
;
Jifang GONG
;
Xiaotian ZHANG
;
Yanyan LI
;
Congcong JI
;
Yu SUN
;
Feilong ZHAO
;
Depei HUANG
;
Yuezong BAI
;
Jian LI
;
Lin SHEN
Author Information
- Publication Type:Original Article
- From:Cancer Research and Treatment 2023;55(2):626-635
- CountryRepublic of Korea
- Language:English
-
Abstract:
Purpose:The human epidermal growth factor receptor 2 (HER2) is an established therapeutic target for various kinds of solid tumors. HER2 amplification occurs in approximately 1% to 6% of colorectal cancer. In this study, we aimed to assess the efficacy and safety of trastuzumab in combination with chemotherapy in HER2-positive metastatic colorectal cancer (mCRC).
Materials and Methods:An open-label, phase II trial (Clinicaltrials.gov: NCT03185988) was designed to evaluate the antitumor activity of trastuzumab and chemotherapy in HER2-positive digestive cancers excluding gastric cancer in 2017. Patients from this trial with HER2-positive, KRAS/BRAF wild-type, unresectable mCRC were analyzed in this manuscript. Eligible patients were treated with trastuzumab (8 mg/kg loading dose and then 6 mg/kg every 3 weeks) and irinotecan (120 mg/m2 days 1 and 8 every 3 weeks). The primary endpoint was the objective response rate.
Results:Twenty-one HER2-positive mCRC patients were enrolled in this study. Seven patients (33.3%) achieved an objective res-ponse, and 11 patients (52.4%) had stable disease as their best response. The median progression-free survival (PFS) was 4.3 months (95% confidence interval, 2.7 to 5.9). Four of the 21 patients (19.0%) had grade 3 adverse events, including leukopenia, neutropenia, urinary tract infection, and diarrhea. No treatment-related death was reported. Exploratory analyses revealed that high tumor tissue HER2 copy number was associated with better therapeutic response and PFS. Alterations in the mitogen-activated protein kinase pathway, HER2 gene, phosphoinositide 3-kinase/AKT pathway, and cell cycle control genes were potential drivers of trastuzumab resistance in mCRC.
Conclusion:Trastuzumab combined with chemotherapy is a potentially effective and well-tolerated therapeutic regimen in mCRC with a high HER2 copy number.
