The efficacy of the combination of eribulin and trastuzumab in advanced HER2-positive breast cancer: the results of Russian observational study

The article presents the experience of 19 Russian medical institutions on the use of eribulin in combination with trastuzumab in various treatment lines of metastatic HER2+ breast cancer in routine clinical practice. Aim . The main objective of this retrospective observational study was to evaluate the efficacy and tolerability of eribulin and trastuzumab combo in HER2+ breast cancer patients pretreated with anthracyclines and taxanes. The analysis included 60 patients who received at least 2 cycles of eribulin in combination with trastuzumab. 2 patients (3.3%) received treatment as the 1st line, as the 2nd – 14 (23.3%), as the 3rd – 16 (26.7%), and as the 4th and more – 28 (46.7%). Materials and methods . Complete response was achieved in 2 (3.3%) patients, partial response in 9 (15%), stable disease in 33 (55%), stabilization for more than 6 months in 11 (18.3%), disease progression was detected in 16 (26.7%) patients. The objective response rate was 18.3% in the whole group, the clinical benefit rate – 36.7%. Results . The objective response rate in the group of the luminal subtype (ER/PR+HER2+) was 26.9%, in HER2-overexpressed subtype (ER-PR-HER2+) – 8.8% and 64.7%, respectively, disease progression was recorded 2.3 times more often – 35.3% versus 15.5% in the luminal subtype group. The median progression-free survival in patients with HER2+ breast cancer was 4.95 months (95% confidence interval – CI 3.04–8.29 months), in luminal subtype – 6.38 months (95% CI 3.33–8.54 months), in non-luminal – 4.44 months (95% CI 2.4–7.96 months); p =0.306. The treatment was well tolerated, the spectrum of adverse events corresponded to the eribulin toxicity profile. Conclusions . The uniqueness of this study lies in the fact that on a large clinical material from the standpoint of real clinical practice, a very promising treatment regimen that is not used routinely in a number of countries has been studied, its effectiveness and satisfactory tolerance have been confirmed.