Impact of eribulin on overall survival in patients with metastatic breast cancer with visceral disease.

239 Background: Visceral disease is associated with poor survival outcome in women with metastatic breast cancer (mBC). Eribulin mesylate is a nontaxane microtubule dynamics inhibitor indicated for 3rd-line monotherapy in patients (pts) with mBC previously treated with at least two chemotherapeutic regimens in the metastatic setting, including an anthracycline and a taxane.,Evidence from the global, randomized, multicenter, phase III clinical trial of eribulin in mBC (EMBRACE) demonstrated improved overall survival (OS) for eribulin-treated pts when compared to treatment of physician's choice (TPC). In this unplanned subgroup analysis, we compare the clinical benefit of eribulin to TPC in mBC pts with visceral disease using the Independent Review database. Patients were categorized as having visceral disease if they had target or non-target lesion involvement in the adrenal gland, liver, lung, pleural, pericardial/peritoneal cavity, spleen, or thyroid. Patients with brain metastases were excluded from the trial.,EMBRACE enrolled 762 pts with mBC, with single organ disease present in 120 pts (15.7%). The remaining pts had multi-organ disease. A total of 81.9% (624) of pts were classified as having visceral disease-81.3% (413) randomized to receive eribulin and 83.1% (211) to receive TPC. Metastatic tumor site was similar in eribulin and TPC arms, with liver (58.3%; 62.6%), lung (38.8%; 37.4%) and pleural (17.1%; 16.5%) involvement. Patients with visceral disease treated with eribulin demonstrated a significant benefit in OS compared to TPC (HR 0.77, p=0.02). Median OS in mBC pts with visceral disease was 12.45 months (mos) for eribulin-treated pts, with ORR=11.0% and CBR*=21.7% compared to OS=10.12 mos, ORR=5.0%, CBR*=16.6% for TPC-treated patients (*CBR defined as CR+PR+SD>6mos). No significant treatment difference was observed in the non-visceral disease patients however due to the small number of patients with non-visceral disease, no robust statistical conclusions can be made.,Treatment with eribulin resulted in significant improvement in overall survival for mBC pts with visceral disease compared to other commonly used chemotherapeutic agents.