Multicenter study of the eValuation of Eribulin (E) use in Sicily in metastatic breast cancer (MBC): A Prospective RegistrY (VESPRY trial)

Abstract

Background: Eribulin mesylate is a non taxane microtubule dynamics inhibitor that represents a firmly established therapeutic option for the treatment of MBC. Methods: This is an ongoing, open‐label, multi‐institutional, prospective, post‐marketing observational, single arm study of the use of E for the treatment of third line of patients ( pts) with pretreated locally advanced or metastatic breast cancer. This study is being conducted in 14 oncology centers in Sicily. The estimated enrollment is 120 pts who will receive, after two lines of chemotherapy for MBC, at least one dose of E at 1.23 mg/m2 on days 1 and 8 of every 21‐day cycle. Pts will receive E until progression. A population analysis of 120 patients will ensure a precision deemed sufficient for the estimation of the confidence interval at 95% of the percentage of pts with severe neutropenia (grade 3‐4), expected to be around 45% in this population. Primary Endpoints: safety profile of the Eribulin and response according to the site of metastases. Secondary Endpoint: evaluation of response according to different subtypes of breast cancer. Results: At the time of this analysis 69 pts were collected. Median age was 60.5 (range 30‐79). All pts received previously anthracycline and taxane based therapies. Subtypes: Luminal A 78%, Luminal B 6%, HER2 enriched 6% and Triple Negative 10%. The main site of metastases was: lung 45%, bone 38% and liver 27%. A median of 5 cycles of Eribulin (range 1‐21) was administrated. Acceptable and manageable safety toxicity profile was recorded (G2 diarrhea 23%, asthenia G1 23%, G1‐G2 neutropenia 18%, G1 neurotoxicity 18%). We reported only one case G4 mucositis, leading to treatment interruption. Overall response rate was 23% (all Partial Response) and Stable Disease 60%. We performed an organ‐specific analysis that revealed an higher rate of stabilization in the lung lesions compared to other site of metastases (lung 82%, liver 65% and brain 63%). The estimated median Time to Progression was 4 months (range 1‐9). Conclusions: This preliminary analysis showed that Eribulin in third line setting has a favorable safety profile and a comparable efficacy to that reported in the pivotal trial (Cortes J, 2011).