Table_1_Real-World Clinical Outcomes of Biosimilar Trastuzumab (CT-P6) in HER2-Positive Early-Stage and Metastatic Breast Cancer.docx

BackgroundThe trastuzumab biosimilar CT-P6 has demonstrated equivalent efficacy and comparable safety to reference trastuzumab (RTZ) in clinical trials of human epidermal growth factor receptor 2 (HER2)-positive early breast cancer (EBC). Here, we present the first real-world comparison of CT-P6 versus RTZ with dual HER2-targeted therapy for the neoadjuvant and palliative first-line treatment with HER2-positive EBC and metastatic breast cancer (MBC) patients in two tertiary hospitals in Korea.
MethodsWe retrospectively investigated medical records in the Severance Breast Cancer Registry in Korea. We identified patients with HER2-positive EBC (n=254) who had received neoadjuvant chemotherapy with RTZ or CT-P6, plus pertuzumab, carboplatin and docetaxel (TCHP) and untreated stage IV MBC (n=103) who had received palliative first-line treatment with RTZ or CT-P6, plus pertuzumab and docetaxel (THP) between May 2014 and December 2019. The primary endpoints were pathologic complete response (pCR) in the EBC and progression-free survival (PFS) in the MBC cohort. Overall survival (OS), overall response rate (ORR), disease control rate (DCR), and cardiac safety were secondary endpoints.
ResultsA similar percentage of EBC patients achieved a pCR with CT-P6 versus RTZ (74.4% [93/125]) vs 69.8% [90/129], p=0.411). For patients with MBC, median follow-up duration was 23.0 and 41.0 months for CT-P6 and RTZ groups, respectively; median PFS did not differ significantly between two groups (13.0 vs 18.0 months, 95% confidence intervals (CIs) 0.0-26.6 vs 11.3-24.7, p=0.976). The ORR, DCR, and cardiac safety profiles did not also show significant difference efficacy outcomes between two groups.
ConclusionsThese real-world data suggest that biosimilar trastuzumab CT-P6 has similar effectiveness and cardiac safety to RTZ in HER2-positive EBC and MBC patients, when administered as part of dual HER2-targeted therapy with pertuzumab plus chemotherapy in the neoadjuvant or palliative setting.

背景 曲妥珠单抗生物类似药CT-P6在人表皮生长因子受体2（human epidermal growth factor receptor 2, HER2）阳性早期乳腺癌（early breast cancer, EBC）的临床试验中，已被证实与原研曲妥珠单抗（reference trastuzumab, RTZ）具有等效的疗效与相当的安全性。本研究首次针对韩国两所三级医院的HER2阳性EBC及转移性乳腺癌（metastatic breast cancer, MBC）患者，对比CT-P6与RTZ联合双靶HER2治疗方案在新辅助治疗及一线姑息治疗中的应用效果。

方法 本研究回顾性分析了韩国延世Severance乳腺癌登记系统（Severance Breast Cancer Registry）的医疗记录。我们筛选了2014年5月至2019年12月期间，接受含原研曲妥珠单抗或CT-P6、帕妥珠单抗、卡铂及多西他赛（TCHP）新辅助化疗的HER2阳性EBC患者（n=254），以及接受含原研曲妥珠单抗或CT-P6、帕妥珠单抗及多西他赛（THP）一线姑息治疗的未经治疗IV期MBC患者（n=103）。本研究的主要终点为EBC队列的病理完全缓解（pathologic complete response, pCR）与MBC队列的无进展生存期（progression-free survival, PFS）；次要终点包括总生存期（overall survival, OS）、客观缓解率（overall response rate, ORR）、疾病控制率（disease control rate, DCR）及心脏安全性。

结果 接受CT-P6治疗的EBC患者与RTZ组的pCR率相似（74.4% [93/125] vs 69.8% [90/129]，p=0.411）。对于MBC患者，CT-P6组与RTZ组的中位随访时间分别为23.0个月与41.0个月；两组中位无进展生存期无显著差异（13.0个月 vs 18.0个月，95%置信区间（confidence intervals, CIs）0.0~26.6 vs 11.3~24.7，p=0.976）。两组的客观缓解率、疾病控制率及心脏安全性亦未表现出显著差异。

结论 本研究的真实世界数据表明，在新辅助治疗或姑息治疗场景中，当曲妥珠单抗生物类似药CT-P6联合帕妥珠单抗与化疗组成双靶HER2治疗方案时，其在HER2阳性EBC及MBC患者中的疗效与心脏安全性均与原研曲妥珠单抗相当。