Long-term efficacy and safety of a third-line treatment with eribulin plus trastuzumab in a young breast cancer patient.

Eribulin mesylate is approved for the treatment of metastatic breast cancer (MBC) patients after progression with anthracyclines and taxanes. Eribulin appears especially promising when combined with trastuzumab, according to the results of a recent Phase II trial in first-line setting. Here we report the case of a young, pretreated, HER2(-) MBC patient, who achieved a long-term clinical benefit with eribulin alone and in combination with trastuzumab after re-biopsy on liver metastases showed HER2 amplification. Although it is unique for its evolving clinical/biomolecular picture, this case adds anecdotal evidence to the efficacy and tolerability of this combination. However, Phase III trials are warranted to confirm its potential in first and subsequent lines of MBC treatment.