Further analyses of Study 301, which compared eribulin to capecitabine in the treatment of advanced breast cancer, showed greater improvements in quality of life (QOL) with eribulin, and overall survival (OS) benefits in subsets of patients.
The open-label, randomized, phase 3 Study 301 compared the therapies in 1102 women with locally advanced or metastatic breast cancer previously treated with no more than 2 regimens, including anthracyclines and taxanes. Median OS was numerically but not significantly improved with eribulin in the overall population: 15.9 versus 14.5 months (hazard ratio [HR] = 0.88; P = .056).
The additional analyses of Study 301 were presented at the 2013 American Society of Clinical Oncology (ASCO) Annual Meeting.1,2
New Findings on Quality of Life in Study 301
Study 301 included QOL as a secondary end point, exploring patients’ experience of symptoms, functions, and overall well-being. The analysis found significantly greater improvements in QOL among patients treated with eribulin, reported Javier Cortes, MD, of Vall D’Hebron University Hospital in Barcelona, Spain.
QOL was assessed with the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) and the breast cancer–specific supplementary measure (QLQ-BR23), administered at baseline, 6 weeks, and 3, 6, 12, 18, and 24 months after the start of treatment (or until progressive disease or treatment change) and at unscheduled visits.
End points included the absolute change from baseline for Global Health Status (GHS), overall QOL, and for each functional domain and symptoms score. Functional domains and symptoms were standardized into a scale from 0 (worst) to 100 (best). An increase in scores indicated improvement in functional domains and deterioration of symptoms.
GHS and overall QOL scores were low at baseline for both arms (approximately 55) but they improved to a significantly greater degree for patients receiving eribulin than for those receiving capecitabine, with an estimated treatment effect of 6.52 (P = .048), Cortes reported.
“Over time, GHS and overall QOL scores improved in both arms but significantly more so for eribulin, suggesting subjective patient benefit,” he said.
Patients receiving eribulin also had significantly better cognitive functioning (P <.001), whereas emotional functioning significantly improved for patients receiving capecitabine (P = .033). The estimated treatment effect for cognitive functioning was quite large, 15.33. The treatment effect for capecitabine with regard to emotional functioning was 3.29.
“Changes in symptoms appeared to mirror the adverse event profiles of the 2 drugs,” Cortes indicated. “As expected, advantages in parameters linked to gastrointestinal effects were observed with eribulin, while advantages in parameters related to hair loss were observed with capecitabine.”
Symptom changes favoring eribulin included improvements in nausea and vomiting (P = .032) and diarrhea (P = .001), while systemic adverse effects (P <.001) and upset related to hair loss changes (P = .023) favored capecitabine. Change in body image was improved more with capecitabine (P <.01). Pain was comparable between the treatments at baseline and diminished at each visit.
The EORTC QLQ-C30 and QLQ-BR23 questionnaires are widely used in international clinical trials to assess the QOL of patients with breast cancer. The QLQ-C30 includes 5 functional scales, 3 symptom scales, and 1 GHS scale. The QLQ-BR23 is a specific questionnaire containing 23 items measuring functioning and symptoms related to breast cancer.
Overall Survival Improvements
While the primary analysis of OS did not meet the predefined criterion for statistical significance in Study 301, the investigators hypothesized that significant differences might be observed within certain patient subgroups.
The 1102 patients were randomized to receive eribulin or capecitabine as their first- (20.0%), second- (52.0%), or third-line treatment (27.2%) for advanced disease. The median number of treatment cycles was 6 for eribulin and 5 for capecitabine.
“A nonsignificant trend favoring improved overall survival with eribulin compared with capecitabine, consistent with the results of the overall population, was maintained over most patient subgroups, including those receiving study treatment as their first-, second-, or third-line regimen for advanced disease,” according to Peter A. Kaufman, MD, of the Norris Cotton Cancer Center at Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, who presented the study at ASCO.
Some patient subgroups seemed to have a greater benefit in survival with eribulin compared with capecitabine. In particular, median OS was improved by eribulin in patients with the following characteristics:
- Human epidermal growth factor receptor 2 (HER2) negative (15.9 vs 13.5 months: HR = 0.84; P = .03)
- Estrogen receptor–negative (14.4 vs 10.5 months: HR = 0.78;
P = .02)
- Triple negative (14.4 vs 9.4 months: HR = 0.70; P = .01)
Also deriving relatively more benefit from eribulin were patients who were Latin American, had nonvisceral disease only, had more than 2 organs involved, had progressed more than 6 months after their last chemotherapy, and had received an anthracycline and/or taxane in the metastatic setting (versus the neoadjuvant or adjuvant setting), he said.
1. Cortes J, Awada A, Kaufman PA, et al. Quality of life (QoL) in patients (pts) with locally advanced or metastatic breast cancer (MBC) previously treated with anthracyclines and taxanes who received eribulin mesylate or capecitabine: a phase III, open-label, randomized study. J Clin Oncol. 2013;31(suppl):Abstract 1050. Presented at: 2013 American Society of Clinical Oncology Annual Meeting; May 31-June 4, 2013; Chicago, IL.
2. Kaufman PA, Cortes J, Awada A, et al. A phase III, open-label, randomized study of eribulin mesylate versus capecitabine in patients with locally advanced or metastatic breast cancer (MBC) previously treated with anthracyclines and taxanes: subgroup analyses.
J Clin Oncol. 2013;31(suppl):Abstract 1049. Presented at: 2013 American Society of Clinical Oncology Annual Meeting; May 31-June 4, 2013; Chicago, IL.