The relative effectiveness of eribulin for advanced breast cancer treatment: a study of the southeast Netherlands advanced breast cancer registry

Figures & data

Table 1. Patient characteristics in each group.

Treatment group	Eribulin (N)	%	Treatment line matched non-eribulin	%	Unmatched non-eribulin	%
Number of patients	45		45		74
Age, median (min–max)	61	(41–73)	56 (40–74)		60 (29–77)
Tumor subtype
ER+/HER2−	25	56%	25	56%	45	61%
ER+/HER2+	4	9%	4	9%	18	24%
ER−/HER2+	2	4%	2	4%	5	7%
Triple negative	11	24%	14	31%	6	8%
Unknown	3	7%	0	0	0	0
Dominant metastatic site
CNS	10	22%	7	16%	12	16%
Visceral	31	69%	35	78%	52	70%
Non-visceral	4	9%	3	7%	10	14%
Bone only^a	2	4%	3	7%	9	12%
Unknown	0	0%	0	0%	0	0%
Number of metastatic sites
1	2	4%	4	9%	12	16%
2	12	27%	11	24%	17	23%
3	15	33%	10	22%	18	24%
4	8	18%	13	29%	14	19%
5+	8	17%	7	16%	13	17%
Number of previous endocrine therapy lines in the ABC setting
0	16	36%	19	42%	20	27%
1	7	16%	6	13%	13	18%
2	7	16%	3	7%	13	18%
3	5	11%	9	20%	16	22%
4+	10	22%	8	18%	12	16%
Number of previous chemotherapy lines in the ABC setting
2	15	33%	17	38%	49	66%
3	13	29%	11	24%	13	18%
4+	17	37%	17	37%	12	16%
Number of previous chemotherapy lines in all settings, i.e., (neo)adjuvant and ABC settings
2	4	9%	3	7%	9	12%
3	13	29%	17	38%	41	55%
4	13	29%	14	31%	16	22%
5+	15	33%	11	24%	8	11%

^a Subgroup of non-visceral metastasis.

ABC: advanced breast cancer; CNS: central nervous system; ER: endocrine receptor status, HER2: human epidermal growth factor 2 receptor.

Table 2. Chemotherapy regimens administered to the treatment line matched non-eribulin group, n = 45.

Chemotherapy regimens	N	%
Anthracycline-based chemotherapy
Doxorubicin in non-pegylated liposomes	5	11%
Taxane-based chemotherapy
Docetaxel	2	4%
Paclitaxel	1	2%
Paclitaxel, trastuzumab, carboplatin, pertuzumab	1	2%
Capecitabine-based chemotherapy
Capecitabine	11	24%
Capecitabine-lapatinib	1	2%
Capecitabine-neratinib	1	2%
Carboplatin-based chemotherapy
Carboplatin	6	13%
Carboplatin-paclitaxel	1	2%
Other
Gemcitabine	3	7%
T-DM1	2	4%
Vinorelbine	10	22%
CMF–trastuzumab^a	1	2%

^a Intravenous cyclophosphamide.

CMF: cyclophosphamide, methotrexate and 5-fluorouracil; T-DM1: trastuzumab-emtansine.

Figure 1. Comparison of progression-free survival (A) and overall survival (B) between the eribulin and the treatment line matched non-eribulin group. CI: confidence interval; OS: overall survival; PFS: progression-free survival.

Table 3. Results of the multivariate Cox proportional hazard models.

	PFS			OS
Covariates	Coefficient (SE)	Hazard ratio (95% CI)	Significance	Coefficient (SE)	Hazard ratio (95% CI)	Significance
Treatment
Non-eribulin	Reference	1.00	–	–	1.00	–
Eribulin	−0.19 (0.26)	0.83 (0.49–1.38)	0.47	−0.42 (0.27)	0.66 (0.38–1.13)	0.13
Tumor subtype
HR+/HER2−	Reference	1.00	–	–	1.00	–
HR+/HER2+	−0.60 (0.47)	0.55 (0.22–1.37)	0.20	−1.05 (0.51)	0.35 (0.13–0.94)	0.04
HR−/HER2+	0.01 (0.66)	1.01 (0.28–3.66)	0.98	−0.42 (0.76)	0.66 (0.15–2.93)	0.58
Triple negative	1.02 (0.28)	2.76 (1.58–4.81)	<0.01	0.97 (0.31)	2.63 (1.44–4.78)	<0.01
Unknown	0.41 (0.72)	1.50 (0.37–6.12)	0.57	0.95 (0.74)	2.60 (0.61–11.09)	0.20
Age at treatment start	<−0.01 (0.01)	0.99 (0.96 − 1.02)	0.59	<0.01 (0.02)	1.01 (0.98 − 1.04)	0.67
Number of previous chemotherapy lines for ABC
2	Reference	1.00	–	–	1.00	–
3	−0.65 (0.35)	0.52 (0.26–1.04)	0.06	−0.25 (0.36)	0.78 (0.39–1.58)	0.49
4+	0.33 (0.31)	1.40 (0.77–2.55)	0.27	0.54 (0.31)	1.72 (0.93–3.19)	0.08
Presence of CNS metastasis
No CNS metastasis	Reference	1.00	–	–	1.00	–
CNS metastasis	0.76 (0.36)	2.15 (1.06–4.33)	0.03	0.98 (0.40)	2.67 (1.22–5.86)	0.01

CI: confidence interval; CNS: central nervous system; HER2: human epidermal growth factor 2 receptor; HR: hormonal status; SE: standard error.

Table 4. Overview of adverse events leading to dose delay or reduction in the eribulin group, n = 45.

Toxicities	Number of patients	%
Leucopenia or neutropenia	6	13%
Neuropathy	4	9%
Gastro-intestinal complaints	3	7%
Fatigue	2	4%
Febrile neutropenia	1	2%
Stomatitis	1	2%
Asymptomatic decreased left ventricular ejection fraction	1	2%
Thrombocytopenia	1	2%
Liver test abnormalities	1	2%
Other	1	2%