326P - National multicentre retrospective study on metastatic breast cancer patients to characterize long responder under eribulin: LORELINE study

Background

Eribulin (ERI) can respresent a therapeutic alternative for advanced breast cancer patients (pts) who have received at least one or two lines of anthracyclines-based chemotherapy and taxanes therapy. In this study, we focused on long responder patients, i.e. with objective response or stability ≥ 6 months (mo.) under ERI, in order to better characterize them.

Methods

Metastatic breast cancer pts treated by ERI in 2^nd, 3^rd or 4^th line between Sep-2011 and June-2018 were selected. The following parameters were assessed: primary tumor and metastasis characteristics, type of response and duration, disease progression, treatment received, toxicities, survival (progression free survival (PFS), overall survival (OS)) and predictive factors of PFS. A special focus was set on pts with hepatic disease (HD).

Results

Among the 98 pts included, analysis was conducted on 84 pts (median age 62) with a majority of HR+ tumor (89% HR+; 6% TN and 5% unknown), 81% of pts had visceral disease and 89% had non visceral disease. ERI was received in 2^nd, 3rd and 4th line of metastatic treatment for respectively 21%, 44% and 35% pts. Complete response (CR), partial response (PR) and stable disease (SD) were observed respectively for 2.4%, 46.4% and 51.2% of pts. The median duration of response was 25.6 weeks (95 IC 22-27.7) with a median number of infusions of 6. Response was similar irrespective of ERI line number. HD was observed in 70.2% of pts with 3.4% of CR, 50.8% of PR and 45.8% of SD. The median PFS was 9 mo. (95 %CI 8-10). Subgroup analysis showed similar PFS irrespective of HD (p=0.21) and treatment line (p=0.46). The median OS was 24 mo. (95% IC 20-31). Predictive factors of PFS in univariate analysis were progesterone receptor expression (p=0.014), number of ERI infusions (p=0.011) and duration of response (p<0.001); in multivariate analysis the main predictive factor was duration of response (p=0.003). The same predictive factors were found for pts with HD.

Conclusions

Response to ERI and PFS were independent of presence of hepatic metastasis and number of line by ERI. The duration of response, number of line by ERI and positive progesterone receptor are the main predictive factors of PFS in our cohort and in pts with HD.

Clinical trial identification

NCT03771183.

Editorial acknowledgement

Legal entity responsible for the study

Centre Jean Perrin.

Funding

Eisai.

Disclosure

All authors have declared no conflicts of interest.