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

Soong June Bae, Jee Hung Kim, Sung Gwe Ahn, Hei Cheul Jeung, Joohyuk Sohn, Gun Min Kim, Min Hwan Kim, Seung Il Kim, Seho Park, Hyung Seok Park, Ji Ye Kim, Joon Jeong

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Background: The 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. Methods: We 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. Results: A 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. Conclusions: These 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.

Original languageEnglish
Article number689587
JournalFrontiers in Oncology
Publication statusPublished - 2021 Jun 4

Bibliographical note

Funding Information:
Medical writing support (including development of a first draft, based on an outline provided by the authors, and subsequent drafts in consultation with the authors, assembling tables and figures, collating author comments, copyediting, fact checking, and referencing) was provided by Beatrice Tyrrell, DPhil, at Aspire Scientific Limited (Bollington, UK), and funded by Celltrion Healthcare (Incheon, Republic of Korea).

Publisher Copyright:
© Copyright © 2021 Bae, Kim, Ahn, Jeung, Sohn, Kim, Kim, Kim, Park, Park, Kim and Jeong.

All Science Journal Classification (ASJC) codes

  • Oncology
  • Cancer Research


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