Multicenter study of the evaluation of eribulin (E) use in Sicily in metastatic breast cancer (MBC): A prospective registry (VESPRY trial).

Abstract

e12565 Background: Eribulin Mesylate is a non taxane microtubule dynamics inhibitor, approved for heavily-pretreated MBC patients (pts). Methods: This is a multicenter, prospective, single arm study for E-treatment of third line in pretreated MBC pts, conducted in 14 oncology centers in Sicily. All pts had received two previous chemotherapy regimens for MBC. Pts received E at 1.23 mg/m2 on days 1,8 every 3 weeks until progression. Primary Endpoints: overall response rate (ORR) according to the site of metastases and safety. Secondary objectives: Progression-free survival (PFS) and ORR according to different subtypes. PFS curve was estimated using the Kaplan-Meier method. Multivariable logistic regression model were used to evaluate the associations of each variables with tumor response. ORR was assessed according to RECIST 1.1 and safety with CTCAE v4.0. Results: 122 pts were enrolled and received at least 1 dose of E. Median age was 58 (range 29-79). All received previously anthracycline and taxane based-therapies. Subtypes: Luminal A 69%, Luminal B 7%, HER2 enriched 4% and Triple Negative 20%. The most common metastatic sites were bone and liver; 67% had metastatic disease involving two or more organs. A median of 5 cycles of E (range 1-26) was administrated. 106/122 pts were evaluable for efficacy, all for safety. ORR was 48%. Exploratory subset analysis showed significantly higher ORR in the lung, liver and bone lesions compared to other site of metastases and in HER2 negative pts. Multivariable regression model showed that HER2 positive subtype was correlated with a poor response (odd ratio 6.7, 95% CI 1.2-36.5). The median PFS was 14.7 months (mos) (95% CI 7.2–25.7). Among pts with < 65 and ≥ 65 years, the median PFS was 14.7 and 25.7 mos, respectively. Most common toxicities: G2 diarrhea 1%, asthenia G1 4%, G2 neutropenia 6%, G1 neurotoxicity 5%, QT prolongation 1%, G4 mucositis in only one case. Conclusions: This study showed a significant improved of PFS with E in third line setting and a favorable safety profile compared with results reported in the pivotal trial. Our findings suggest that E has substantial antitumor activity when used early for the treatment for MBC with acceptable safety.