Background: Eribulin mesylate is a nontaxane microtubule dynamics inhibitor approved for second-line (European Union) or third-line (United States) treatment of metastatic breast cancer. Two phase 2 single trials, evaluating first-line eribulin as monotherapy (Study 206; NCT01268150) or in combination with trastuzumab (Study 208; NCT01269346) in locally recurrent or metastatic breast cancer, demonstrated objective response rates of 28.6 and 71.2%, respectively. Median progression-free survival was 6.8 and 11.6 months, respectively. Tolerability profiles were similar to those from previous studies. This secondary analysis was conducted to assess health-related quality of life (HRQoL) in both phase 2 trials.
Methods: Patients received eribulin mesylate 1.4 mg/m2 intravenously on days 1 and 8 of each 21-day cycle. Patients in Study 208 also received intravenous trastuzumab on day 1 of each cycle (8 mg/kg in cycle 1, then 6 mg/kg). HRQoL was assessed by the European Organization for Research and Treatment of Cancer Quality-of-Life (QLQ-C30) assessment tool and the Quality-of-Life Questionnaire for Breast Cancer (QLQ-BR23) at baseline and cycles 2, 4, and 6. Results for clinically meaningful changes were based on previously published minimum important differences.
Results: Of the 108 patients (56 in Study 206 and 52 in Study 208) treated, 57 and 87%, respectively, completed 6 cycles. Completion rates for both questionnaires were 94 and 98%, respectively, at cycle 6. Most patients had stable/improved HRQoL scores with some exceptions; for example, more patients experienced a worsening in cognitive functioning and systemic therapy side effects than experienced improvement. Mean QLQ-C30 symptom scores correlated with corresponding adverse event rates for nausea/vomiting, dyspnea, appetite loss, constipation, and diarrhea in Study 206 and for fatigue, nausea/vomiting, pain, dyspnea, insomnia, constipation, and diarrhea in Study 208.
Conclusions: First-line eribulin ± trastuzumab therapy did not lead to deterioration of overall HRQoL in most patients, with more than 60% of patients having stable/improved global health status/quality-of-life scores. Eribulin has been demonstrated to be comparable with other chemotherapy agents with an acceptable safety profile. Therefore, further evaluation is warranted to determine whether eribulin ± trastuzumab therapy may be a potential option for first-line treatment in some patients with metastatic breast cancer who were recently treated in the neoadjuvant setting.
Trial registration: NCT01268150 (December 29, 2010), NCT01269346 (January 4, 2011).
Keywords: Eribulin; First-line therapy; Health-related quality of life; Metastatic breast cancer; Trastuzumab.