Abstract 921
Background
Eribulin mesylate (ERI) exerts anticancer activity in both early- and late-line settings in the management of ER+HER2- metastatic breast cancer (MBC) patients; however, the utility of rechallenge or a second administration of ERI has not been well discussed.
Methods
The outcomes of ER+HER2-MBC patients who received ERI therapy at our institute from November 2011 to the present were reviewed. Statistical analyses were performed using the Kaplan-Meyer method and Spearman's rank correlation coefficient.
Results
We identified 90 ER+HER2-MBC patients who had terminated their first-line of ERI therapy (1stERI), with a median time-to-treatment failure (TTF) of 134.0 days (95% confidence interval [CI]115.6-152.4), and 22 of 90 (24.4%) underwent a 2ndERI. Of these 22 patients, the TTF was significantly better than at the 1stERI compared with patients who did not undergo 2ndERI (median 181.0 days vs. 119.0 days; P < 0.01). Patients received a median of 2 (range 1-5) regimens between the 1st- and 2nd- ERI, and the median number of regimens patients received prior to 2ndERI was 4 (range 2-10). A majority (16/22, 72.7%) received chemotherapy prior to the 2ndERI. The median TTF of prior systemic therapy was 141.0 days (95% CI 70.9-211.1), and the major cause of discontinuation was progression of known lesions (19/22, 86.4%). The median TTF of the 2ndERI was 97.0 days (95% CI 82.2-111.8), and causes of discontinuation (excluding 1 patient still on treatment) were as follows: progression of known lesions, 14 (66.7%); development of new lesions, 2 (9.5%) and others, 5 (23.8%). Among them, 3 pts achieved stable disease for ≥24 weeks. Subsequent systemic therapy was introduced to 16/21 (76.2%) patients, and 11 received chemotherapy. The median overall survival (OS) from the induction of the 2ndERI was 268.0 days (95% CI 16.1-519.9), and the median OS from the induction of the 1stERI was significantly improved by the 2ndERI (898.0 days vs. 421.0 days; P < 0.001). A significant (P < 0.001) relationship existed between the TTF of the 2ndERI and the OS from the induction of the2ndERI. No significant safety signals were noted.
Conclusions
Re-challenging eribulin is thus considered to be a viable option for patients with ER+HER2-MBC in terms of the efficacy and safety.
Editorial acknowledgement
Clinical trial identification
Legal entity responsible for the study
Junichiro Watanabe.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.