Final overall survival analysis of the phase 3 HERITAGE study demonstrates equivalence of trastuzumab-dkst to trastuzumab in HER2-positive metastatic breast cancer

Breast Cancer Res Treat. 2021 Jul;188(2):369-377. doi: 10.1007/s10549-021-06197-5. Epub 2021 Jun 14.


Purpose: The phase 3 HERITAGE trial demonstrated that the biosimilar trastuzumab-dkst is well tolerated with similar efficacy (measured by overall response rate [ORR] and progression-free survival [PFS]) compared with originator trastuzumab combined with taxane followed by monotherapy in patients with HER2-positive metastatic breast cancer (MBC). Herein, we present final overall survival (OS) from HERITAGE.

Methods: HERITAGE is a multicenter, double-blind, randomized, parallel-group study. Patients were randomized 1:1 to receive trastuzumab-dkst or trastuzumab plus taxane followed by continued monotherapy until disease progression. Overall survival was to be assessed at 36 months or after 240 deaths, whichever occurred first, as observed from time of randomization of last patient.

Results: At the final analysis (36 months), 242 patients in the intention-to-treat population had died during the study: 116 and 124 in the trastuzumab-dkst and trastuzumab groups, respectively, and 1 untreated patient from each treatment group. Median OS by Kaplan-Meier analysis was 35.0 months with trastuzumab-dkst and 30.2 months with trastuzumab. Evaluation of PFS showed a median of 11.1 months in both treatment groups. No new safety concerns were reported from week 48 until the end of the survival follow-up.

Conclusion: This is the first phase 3 trial of a trastuzumab biosimilar to report long-term survival data similar to originator trastuzumab in patients with MBC. The comparable long-term OS between the trastuzumab-dkst and originator trastuzumab groups further supports the similarity of trastuzumab-dkst with originator trastuzumab and establishes trastuzumab-dkst as a safe and effective treatment option for patients with HER2-positive MBC. NCT02472964; 6/16/2015.

Keywords: Biosimilar; Metastatic breast cancer; Overall survival; Trastuzumab.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial

MeSH terms

  • Antibodies, Monoclonal, Humanized / therapeutic use
  • Antineoplastic Combined Chemotherapy Protocols / adverse effects
  • Breast Neoplasms* / drug therapy
  • Female
  • Humans
  • Receptor, ErbB-2 / genetics
  • Survival Analysis
  • Trastuzumab / therapeutic use
  • Treatment Outcome


  • Antibodies, Monoclonal, Humanized
  • Receptor, ErbB-2
  • Trastuzumab

Associated data