by Tobias Berg, Maj-Britt Jensen, Erik H. Jakobsen, Sami
Al-Rawi, Julia Kenholm, Michael Andersson
The Breast: VOLUME 54, P242-247, DECEMBER 01,
2020
Highlights
•Real world data on 215 patients with HER2-positive early
breast cancer.
•SB3 (biosimilar trastuzumab) and pertuzumab with
neoadjuvant chemotherapy.
•pCR in 56% and node conversion in 68% of the patients.
•pCR rate associated with ER-status and malignancy grade.
Abstract
Background
Dual blockade with trastuzumab and pertuzumab combined with
neoadjuvant chemotherapy (NACT) has been increasingly used for HER2-positive
tumours >2 cm and/or with positive axillary lymph nodes in order to
evaluate pathologic response and obtain better surgical management. SB3 is a
registered biosimilar trastuzumab approved following a phase III trial
demonstrating similar efficacy in the neoadjuvant setting as trastuzumab.
However, the study was done without pertuzumab.
Method
The database of the Danish Breast Cancer Group was used to
extract data on all patients who started NACT with SB3 and pertuzumab between
September 1, 2018 and August 31, 2019. The primary endpoint was pathological
complete response (pCR) rate.
Results
In total 215 patients received NACT and dual blockade. The
median age was 55 (24–81). NACT used was cyclophosphamide and epirubicin
followed by weekly paclitaxel (62% on six cycles, 35% on eight cycles) or other
chemotherapy followed by weekly paclitaxel (3%). Overall, 56% of patients achieved
pCR. 60 of 88 node-positive patients pre-NACT achieved ypN0(i-) after
neoadjuvant treatment. pCR rate was significantly associated with estrogen
receptor status and malignancy grade. An association with CEP17/HER2-ratio was
assessed.
Conclusion
Real world data on dual blockade with SB3 and pertuzumab in
combination with NACT in a nationwide population-based study show a pCR rate
comparable to that seen in previous clinical studies.
