Background and Importance Eribulin is one of the therapeutic alternatives for patients with metastatic breast cancer. In clinical practice, its use will depend on the particular characteristics of each patient.

Aim and Objectives To review the treatment used with eribulin in our patients and to analyse the effectiveness and safety achieved.

Material and Methods Retrospective observational study of patients diagnosed with metastatic breast cancer was conducted. Age, dose and eribulin cycles received were recorded. Previous lines of treatment were analysed. Progression-free survival (PFS), overall survival (OS) and safety of eribulin treatment in our patients were evaluated.

Results Forty women diagnosed with her2- metastatic breast cancer during January 2021 until January 2023 were included. The mean age was 60 years (42–80 years). 58% (23/40) received full doses of treatment and 42% (17/40) received reduced doses. The average number of cycles received was 6 cycles (2–19). The mean number of treatments prior to eribulin was 3 treatments(1–6). Eribulin was used in most patients in the fourth line of treatment 58%(23/40),second and third line 20% (8/40), fifth line 15%(6/40),between sixth and eighth lines 20%( 8/40).The first line of treatment used was estrogen blockers together with cyclin inhibitors (48%). The second line of treatment was oral capecitabine (45%) and vinorelbine (37%). In the third line capecitabine (18%), vinorelbine (18%), taxol (15%) and liposomal doxorubin (15%).The PFS achieved with eribulin treatment was 6 months(3–20) and the OS was 3 months.(6–2). Eleven (27%) patients were exitus. Grade III adverse reactions described were alopecia (20%), neurotoxicity, neutropenia and pain(2%). Grade II were asthenia, alopecia, mucositis, neurotoxicity and diarrhoea (2% ).Grade I bone pain, mucositis, asthenia, increased transaminase levels (10%).

Conclusion and Relevance Eribulin has been able to be used at full doses despite being an advanced line of treatment in multi-treated patients.

Progression-free survival and overall survival achieved is acceptable as a treatment in patients with advanced metastatic disease.

Alopecia is a frequent and important reaction that can condition the choice of treatment in these patients and justifies the use of eribulin in later lines of treatment.

Conflict of Interest No conflict of interest.