Abstract 3838
Background
SB3 has been approved by the European Commission as a biosimilar of reference trastuzumab (TRZ). Equivalence for efficacy between SB3 and TRZ based on breast pathologic complete response (bpCR) rates has been demonstrated and previously reported.1 Here we report results of subgroup analyses of efficacy by baseline disease characteristics and demographics.
Methods
Patients received either SB3 or TRZ for 8 cycles concurrently given with chemotherapy (docetaxel followed by 5-fluorouracil/epirubicin/cyclophosphamide). Then patients underwent surgery followed by 10 cycles of SB3 or TRZ. The primary endpoint was bpCR rate. Subgroup analyses of bpCR rate, total pathologic complete response (tpCR) rate, and overall response rate (ORR) by region, age, ethnicity, hormone receptor status, breast cancer type, and menopausal status was performed.
Results
800 patients (SB3, n = 402; TRZ, n = 398) were included in the per-protocol set (PPS). The bpCR rates were 51.7% for SB3 and 42.0% for TRZ with adjusted difference of 10.70% (95% CI, 4.13, 17.26). Subgroup analysis results are provided in the table. A trend of favourable efficacy of SB3 compared to TRZ was maintained in most of subgroup analyses. Similar trends were observed in the subgroup analysis of tpCR rate and ORR. Table: bpCR rates by baseline demographics and disease characteristics.Table: 217P
| SB3 n/n’ (%) | TRZ n/n’ (%) | Adjusted difference (%) (SB3-TRZ, 95% CI) | |
|---|---|---|---|
| Region | |||
| Europe | 53/108 (49.1) | 44/98 (44.9) | 3.44 (-9.63, 16.51) |
| Non-Europe | 155/294 (52.7) | 123/300 (41.0) | 13.18 (5.59, 20.77) |
| Age | |||
| Age <45 | 59/121 (48.8) | 48/119 (40.3) | 9.20 (-3.08, 21.48) |
| Age ≥45 | 149/281 (53.0) | 119/279 (42.7) | 11.51 (3.76, 19.26) |
| Ethnicity | |||
| Asian | 68/124 (54.8) | 51/124 (41.1) | 15.52 (4.27, 26.78) |
| White | 135/269 (50.2) | 112/264 (42.4) | 8.45 (0.28, 16.62) |
| Hormone receptor status | |||
| ER and/or PR positive | 119/254 (46.9) | 78/230 (33.9) | 12.87 (4.45, 21.28) |
| ER and PR negative | 89/148 (60.1) | 89/168 (53.0) | 7.34 (-3.14, 17.83) |
| Breast cancer type | |||
| Operable | 120/241 (49.8) | 97/238 (40.8) | 10.14 (1.44, 18.85) |
| Locally advanced | 88/161 (54.7) | 70/160 (43.8) | 11.53 (1.58, 21.48) |
| Menopausal status | |||
| Yes | 105/198 (53.0) | 92/198 (46.5) | 7.65 (-1.33, 16.64) |
| No | 103/204 (50.5) | 75/200 (37.5) | 12.97 (3.81, 22.14) |
CI, confidence interval; ER, oestrogen receptor; PR, progesterone receptor; n, number of patients achieving bpCR; n’, number of patients with available assessment results.
Conclusions
Subgroup analysis results of bpCR, tpCR, and ORR showed a tendency of favourable efficacy in SB3 compared to TRZ, which were consistent with the overall bpCR analysis result. Reference: 1. Pivot X et al. J Clin Oncol. 2018; 36:968-74.
Clinical trial identification
EudraCT: 2013-004172-35.
Legal entity responsible for the study
Samsung Bioepis Co., Ltd.
Funding
Samsung Bioepis Co., Ltd.
Editorial Acknowledgement
Disclosure
J. Cortes Castan: Honoraria: Roche, Novartis, Eisai, Celgene, Pfizer; Consulting/advisor: Roche, Celgene, Aztrazeneca, Cellestia Biotech, Biothera, Merus. X. Pivot: Principle investor: phase III study of SB3; Consultant and honoraria: Samsung Bioepis. G. Curigliano: Fee for a seminar on the abstract. S. Song, Y.C. Yoon: Employment: Samsung Bioepis. All other authors have declared no conflicts of interest.
Resources from the same session
5349 - Prognostic implications of circulating tumor cells (CTCs) after neoadjuvant chemotherapy for triple negative breast cancer (TNBC)
Presenter: Carolyn Hall
Session: Poster display session: Breast cancer - early stage, locally advanced & metastatic, CNS tumours, Developmental therapeutics, Genitourinary tumours - prostate & non-prostate, Palliative care, Psycho-oncology, Public health policy, Sarcoma, Supportive care
Resources:
Abstract
2568 - A prediction model for pathological complete response after neoadjuvant chemotherapy of HER2-negative breast cancer patients
Presenter: Lothar Häberle
Session: Poster display session: Breast cancer - early stage, locally advanced & metastatic, CNS tumours, Developmental therapeutics, Genitourinary tumours - prostate & non-prostate, Palliative care, Psycho-oncology, Public health policy, Sarcoma, Supportive care
Resources:
Abstract
5413 - Evaluation of the MammaTyper® as a molecular predictor for pathological complete response (pCR) after neoadjuvant chemotherapy (NACT) and outcome in patients with different breast cancer (BC) subtypes
Presenter: Peter A. Fasching
Session: Poster display session: Breast cancer - early stage, locally advanced & metastatic, CNS tumours, Developmental therapeutics, Genitourinary tumours - prostate & non-prostate, Palliative care, Psycho-oncology, Public health policy, Sarcoma, Supportive care
Resources:
Abstract
2260 - Impact of clinical, morphologic and molecular characteristics on response to neoadjuvant systemic therapy (NAST) in metaplastic breast cancer (MpBC)
Presenter: Clinton Yam
Session: Poster display session: Breast cancer - early stage, locally advanced & metastatic, CNS tumours, Developmental therapeutics, Genitourinary tumours - prostate & non-prostate, Palliative care, Psycho-oncology, Public health policy, Sarcoma, Supportive care
Resources:
Abstract
4722 - Evaluation of Human epidermal growth factor receptor 2 overexpression (HER2+) after administration of neoadjuvant treatment (NAT) and prognostic impact in breast cancer (BC)
Presenter: Duarte Machado
Session: Poster display session: Breast cancer - early stage, locally advanced & metastatic, CNS tumours, Developmental therapeutics, Genitourinary tumours - prostate & non-prostate, Palliative care, Psycho-oncology, Public health policy, Sarcoma, Supportive care
Resources:
Abstract
4307 - Complete response (CR) to anthracycline-based chemotherapy using magnetic resonance imaging (MRI) predicts high rates of pathologic complete response (pCR) for triple negative breast cancer (TNBC) patients treated preoperatively with anthracycline and taxane-based regimens
Presenter: Maria Marin Alcala
Session: Poster display session: Breast cancer - early stage, locally advanced & metastatic, CNS tumours, Developmental therapeutics, Genitourinary tumours - prostate & non-prostate, Palliative care, Psycho-oncology, Public health policy, Sarcoma, Supportive care
Resources:
Abstract
5018 - Immunomonitoring of triple negative breast cancer patients undergoing neoadjuvant therapy (GBG89, Geparnuevo trial)
Presenter: Barbara Seliger
Session: Poster display session: Breast cancer - early stage, locally advanced & metastatic, CNS tumours, Developmental therapeutics, Genitourinary tumours - prostate & non-prostate, Palliative care, Psycho-oncology, Public health policy, Sarcoma, Supportive care
Resources:
Abstract
3203 - Impact of breast cancer subtype on survival after lumpectomy versus mastectomy for early stage invasive breast cancer
Presenter: YU-CHEN Tsai
Session: Poster display session: Breast cancer - early stage, locally advanced & metastatic, CNS tumours, Developmental therapeutics, Genitourinary tumours - prostate & non-prostate, Palliative care, Psycho-oncology, Public health policy, Sarcoma, Supportive care
Resources:
Abstract
4887 - Survival Outcomes of Dose Dense Neoadjuvant and Adjuvant Chemotherapy in Triple-Negative Breast Cancer Patients – Indian Scenario
Presenter: TANVI Sood
Session: Poster display session: Breast cancer - early stage, locally advanced & metastatic, CNS tumours, Developmental therapeutics, Genitourinary tumours - prostate & non-prostate, Palliative care, Psycho-oncology, Public health policy, Sarcoma, Supportive care
Resources:
Abstract
1449 - Prognostic factors associated with pathological complete response in early breast cancer patients undergoing neoadjuvant chemotherapy. The importance of Ki-67 and molecular subtype.
Presenter: Bernardo Rapoport
Session: Poster display session: Breast cancer - early stage, locally advanced & metastatic, CNS tumours, Developmental therapeutics, Genitourinary tumours - prostate & non-prostate, Palliative care, Psycho-oncology, Public health policy, Sarcoma, Supportive care
Resources:
Abstract