Prognosis of Invasive Lobular Carcinoma and Effectiveness of Eribulin in Clinical Practice: A Post Hoc Analysis of a 2-Year Post-Marketing Surveillance.

Abstract

Aim: Invasive lobular carcinoma (ILC) is the second most common breast cancer type after invasive ductal carcinoma (IDC). Eribulin mesylate (eribulin) is a non-taxane microtubule dynamics inhibitor approved for advanced or metastatic breast cancer, including ILC and IDC. However, real-world data from eribulin-treated patients with advanced or metastatic ILC are scarce.

Methods: This post hoc analysis of a Japanese multicenter, prospective, observational post-marketing surveillance (ClinicalTrials.gov: NCT02371174) evaluated data from eribulin-treated patients with ILC or IDC. Overall survival (OS) from the initiation of first-line chemotherapy, OS from the first date of eribulin administration, and time-to-treatment failure (TTF) were evaluated. OS from eribulin initiation was also evaluated by line of eribulin treatment (first-line, second-line, and third-line or later). Adverse drug reactions (ADRs) with ≥ 5% frequency in both groups were evaluated.

Results: Among patients with ILC (n = 33) and IDC (n = 543), median OS from the initiation of first-line chemotherapy was 25.5 and 39.0 months, respectively (hazard ratio 1.94 [95% confidence interval 1.28-2.94]; p < 0.05), median OS from the first date of eribulin administration was 16.0 and 18.0 months, respectively (1.31 [0.87-1.97]), and TTF was 6 and 5 months (0.92 [0.65-1.32]). No significant differences were observed in median OS when stratified by line of eribulin treatment. Type and frequency of ADRs did not differ significantly between the groups.

Conclusion: OS and TTF after eribulin initiation were similar between ILC and IDC cases, suggesting that eribulin might be a beneficial treatment option for ILC.