Prognosis factors for long-term eribulin response in a cohort of patients with HER2negative metastatic breast cancer

e13120 Background: Eribulin is a drug used since 2010 in metastatic breast cancer. Some prognosis criteria for long progression-free survival are already described in small cohorts. We present an historic cohort to determine new prognosis criteria for long-term eribulin response in HER2-negative metastatic breast cancer. Methods: Our retrospective cohort include female patient with HER2-negative metastatic breast cancer treated with eribulin in Franche-Comté, France. We defined a long-term response as six months of eribulin treatment. The primary endpoint is the analysis of criteria that differ according to the progression-free survival. Secondaries outcomes concern overall survival, response rate and analysis of MDM2/p53 axis. Results: Median progression free survival (PFS) is 3.2 months. 23.6 percent of patients have a long-term response to eribulin. Four discriminant criteria appear to separate progression free survival in two arms (PFS < 3 months or > 6 months) predicting nearly 78% the probability of a prolonged response to eribulin: histological grade, presence of meningeal metastasis, response to prior chemotherapy and OMS status. We have developed a nomogram combining these 4 criteria. Median overall survival is 8.5 months. MDM2 amplification appear not being predictive of therapeutic response in metastatic breast cancer. Conclusions: Eribulin response in metastatic breast cancer can be drive by clinical and biological factors. The application of the nomogram proposed by our analysis can assist the clinician in the therapeutic strategy and prescription of eribulin. These results should be confirmed in real life. Multivariate logistic regression to predict PFS < 3 months vs > 6 months. [Table: see text]