Table 2. Phase II studies in metastatic breast cancer.

Study	Patient population	No. of patients	Setting	Key efficacy and safety findings
211 [18]	Western	291	≥ 3rd line, LABC/mBC	ORR (independent review) = 9.3% (95% CI, 6.1%-13.4%; all PRs), SD rate = 46.5%
				Clinical benefit rate = 17.1%
				PFS 2.6 mo
				OS 10.4 mo
				Most common treatment-related grade 3/4 toxicities were neutropenia (54%); febrile neutropenia (5.5%); leukopenia (14%), and asthenia/fatigue (10%, no grade 4). Grade 3 neuropathy occurred in 6.9% of patients (no grade 4).
201 [19]	Western	193	≥ 2nd line, LABC/mBC	ORR = 11.5% (95% CI, 5.7%-20.1%)
				Clinical benefit rate 17.2% (95% CI, 10.0%-26.8%)
				PFS 79 days (2.6 mo; range, 1-453 days)
				OS 275 days (9.0 mo; range, 15-826 days)
				The most common drug-related grade 3/4 toxicities were neutropenia (64%); leukopenia (18%); fatigue (5%); peripheral neuropathy (5%); and febrile neutropenia (4%)
221 [20]	Japanese*	80	1-4th line, LABC/mBC	ORR = 21.3% (95% CI, 12.9%-31.8%; all PRs)
				Clinical benefit rate = 27.5% (95% CI, 18.1%-38.6%)
				PFS 3.7 mo (95% CI, 2.0-4.4 mo)
				OS 11.1 mo (95% CI, 7.9-15.8 mo)
				Most frequent treatment-related grade 3/4 AEs were neutropenia (95.1%); leukopenia (74.1%); and febrile neutropenia (13.6%)
				Grade 3 peripheral neuropathy occurred in 3.7% of patients (no grade 4)

LABC=locally advanced breast cancer; mBC=metastatic breast cancer; ORR=objective response rate; CI=confidence interval; SD=stable disease; PFS=progression-free survival; OS=overall survival; PR=partial response; AEs=adverse events.

^*Japanese registrational phase II study to support the use of eribulin in Japanese patients with locally advanced or mBC.