Poster viewing and lunch

150P - Pathological complete response after neoadjuvant chemotherapy in Her2 positive breast cancer, efficacy of biosimilar compared to Herceptin® (ID 362)

Lecture Time
12:15 - 12:15
Session Name
Poster viewing and lunch
Room
Exhibition area
Date
Fri, 12.05.2023
Time
12:15 - 13:00
Speakers
  • Nassima Kouadri (Annaba, Algeria)
Authors
  • Nassima Kouadri (Annaba, Algeria)
  • Nèche N. Belili (Annaba, Algeria)
  • Asma Boudersa (Annaba, Algeria)
  • Khadidja Cheikchouk (Annaba, Algeria)
  • Meriem Ressa (Annaba, Algeria)
  • Marwa Ghassoul (Annaba, Algeria)
  • Selsabila Bouacha (Souk ahras, DZ, Algeria)
  • Djedi Hanene (Annaba, Algeria)
  • Taha FILALI (Constantine, Algeria)

Abstract

Background

Trastuzumab biosimilar were first tested and introduced in the metastatic setting. There use in the neoadjuant setting is based on equivalence on pathological complete response rate (pCR), which remain the preferable surrograte factor in Her2-positive tumors. Two biosimilars are available at ower institution since 2017 (Hertraz® 440mg Mylan and CanMab ® AbdiBrahim). The aim of this study is to compre efficacy of trastuzumab biosimilar compared to Referent Trastuzumab based on pCR.

Methods

A retrospctive study was conducted based on 193 files of stage I-III her2-positive breast cancer treated with neoadjuvant chemotherapy (NACT) including trastuzumab only, since pertuzumab is not available at our level. Baseline characteristics between the two groups were compared. A first analyse of relatio between the use trastuzumab and pCR rate was done, then a multivariate analysis added to this parameter significant predictive factors (TNM stage, molecular sub-groupe, ER/PR levels, Ki67, histology).

Results

A total of 99 patients includes in the Referent group and 94 in the biosimilars group. Baseline characteristics are summarized in the table.

Referent trastuzumab Biosimilars
Median age (min-max) 48.1 52.4
Premenopusal (%) 59.6 55.3
T: T1-2-3-4 (%) 6.1-44.4-22.3-28.3 3.2-28.7-31.9-36.2
N: 0-1-2-3 (%) 36.4-53.5-10.6-0 35.1-47.9-6.4-10.6
Stage: I-IIA-IIB-IIIA-IIIB-IIIC (%) 6.1-25.2-24.2-20.2-24.2-0 1.1-19.1-25.5-15.9-27.6-10.6
Histology: IDC-ILC-Other (%) 83.8-14.1-2 89.4-7.4-3.2
ER (median) 30.5% 42.5%
PR (median) 20.6% 30.1%
Ki67 (median) 37.4% 37.3%
Molecular group (Luminal) 52.5% 71.3%

We noticed a statistically significant difference between luminal rate in the two arms (p=0.021) pCR rate in biosimilar arm was 41.5% vs 37.8% in the Referent groupe (p=0.331). In multivariate analysis none of the cited parameters was considered as a predictive factor of pCR.

Conclusions

Our study demonstrated the efficacy of trastuzumab biosomilar compared to Referent trastuzumab in the neoadjuvant setting, since the two arms whowed comparable pCR rates, even if more luminal tumors were recorded in the biosimilar arm, considered as resistance factor to neoadjuvant treatment. This is an important result considering different cost of the two options.

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.

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