Eribulin Mesylate ‘Not Superior’ to Capecitabine for Advanced Breast Cancer

Eribulin mesylate and capecitabine show similar efficacy for patients with locally-advanced or metastatic breast cancer

medwireNews: Phase III clinical trial results suggest that eribulin mesylate does not offer significant survival benefits over those of capecitabine for women with locally-advanced or metastatic breast cancer.

“Our results contrast with those of EMBRACE, in which a statistically significant improvement in OS [overall survival] was seen with eribulin compared with [the physician’s choice]”, report Peter Kaufman, from Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire, USA, and co-authors.

Patients in the current trial were randomly assigned to receive eribulin mesylate (n=554) or capecitabine (n=548) as a first-, second- or third-line treatment for advanced or metastatic breast cancer.

By contrast, the EMBRACE trial included patients with metastatic breast cancer who had received between two and five cytotoxic regimens for advanced disease.

“It is possible that treatment earlier in the course of [metastatic breast cancer] is less likely to impact OS, as a consequence of such patients typically receiving further lines of cytotoxic or other therapy”, the authors hypothesise.

“Even if therapeutically more active, a first- or second-line regimen may not impact on OS when multiple subsequent lines of effective treatment are administered.”

As reported in the Journal of Clinical Oncology, the eribulin mesylate and capecitabine treatment groups had comparable overall survival (median 15.9 vs 14.5 months) and progression-free survival (median 4.1 vs 4.2 months).

Objective response rates were also comparable for the two groups, with independent reviewer values of 11.0% and 11.5% for eribulin mesylate and capecitabine, respectively.

And prespecified analysis found that the efficacy of eribulin mesylate did not significantly differ between patients who were negative for human Epidermal growth factor receptor (HER)2 and those who were HER2-positive or of unknown HER2 status.

“[T]he AE [adverse event] profiles of both treatments in this phase III trial were predictable, manageable, and, overall, clinically acceptable”, the researchers report.

Patients in eribulin mesylate and capecitabine treatment groups had comparable rates of AEs (94.1 vs 90.5%) and serious AEs (17.5 vs 21.1%), with 7.9% and 10.4% of patients discontinuing treatment, respectively.

Global health status and quality of life also did not differ significantly between the two treatment groups.

Reference

Kaufman PA, Awada A, Twelves C, et al. Phase III open-label randomized study of eribulin mesylate versus capecitabine in patients with locally advanced or metastatic breast cancer previously treated with an anthracycline and a taxane. J Clin Oncol 2015; Published online before print 20 January. doi:10.1200/JCO.2013.52.4892

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