The following article features coverage from the European Society for Medical Oncology (ESMO) 2019 meeting. Click here to read more of Cancer Therapy Advisor‘s conference coverage.

Similar efficacy and cardiac toxicity results were observed at 3-year follow-up of a randomized clinical trial comparing trastuzumab and a biosimilar of trastuzumab, trastuzumab-pkrb, in patients with HER2-positive early-stage breast cancer. The findings from this study were reported at the European Society for Medical Oncology (ESMO) Congress 2019 held in Barcelona, Spain.1

Previously reported results from a double-blinded, phase 3 clinical trial (ClinicalTrials.gov Identifier: NCT02162667) comparing women with newly diagnosed stage I to stage IIIa HER2-positive (ie, 3+ by immunohistochemistry) breast cancer patients (549 individuals) randomly assigned (1:1) to receive neoadjuvant trastuzumab or trastuzumab-pkrb (both administered with docetaxel followed by 5-fluorouracil-epirubicin-cyclophosphamide chemotherapy, and then adjuvant trastuzumab or CT-P6 for up to 1 year) showed equivalent efficacy with respect to the rate of pathologic complete response, the primary study end point, and as well as similar treatment safety.On the basis of these results, trastuzumab-pkrb was approved by both the US Food and Drug Administration (FDA) for the treatment of patients with HER2-overexpressing breast cancer.3

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At a median study follow-up of 39 months, similar rates of disease-free survival (DFS; 83% in both arms) and overall survival (OS; 93% [trastuzumab]; 94% [trastuzumab-pkrb]) were observed in the intention-to-treat populations of the 2 study arms.  Neither median DFS nor median OS had been reached. Mean left-ventricular ejection fraction was over 60% in both study arms, and no additional cases of heart failure were reported in the follow-up period of the study.

In their concluding remarks, the study authors noted that these results “support the similarity of [trastuzumab-pkrb] and reference trastuzumab in early-stage breast cancer.”

Disclosure: This study was funded by Celltrion, and some of the authors disclosed payments from the pharmaceutical industry. For a full list of disclosures, please refer to the abstract.

Read more of Cancer Therapy Advisor‘s coverage of the ESMO annual meeting by visiting the conference page.

References

  1. Stebbing J, Baranau Y, Baryash V, et al. 3-year follow-up of a phase III trial comparing the efficacy and safety of neoadjuvant and adjuvant trastuzumab and its biosimilar CT-P6 in HER2 positive early breast cancer (EBC). Presented at: European Society for Medical Oncology (ESMO) Congress 2019; September 27-October 1, 2019: Barcelona, Spain. Abstract 190P.
  2. Stebbing J, Baranau Y, Baryash V, et al. CT-P6 compared with reference trastuzumab for HER2-positive breast cancer: a randomised, double-blind, active-controlled, phase 3 equivalence trial. Lancet Oncol. 2017;18:917-928. 
  3. Trastuzumab-pkrb (Herzuma®) [package insert]. North Wales, PA: Teva Pharmaceuticals, USA, Inc.; 2018.