52P - Chemotherapy selection in routine clinical practice in Japan for HER2-negative advanced or metastatic breast cancer (KBCRN A001: E-SPEC Study)

Background

Anthracycline-based (A) and taxane-based (T) chemotherapy (ChT) are standards of care for triple-negative (TN) or hormone-resistant advanced/metastatic breast cancer (AMBC) in 1st- or 2nd-line ChT. However, the choice of regimen for oncologists and patients is diverse, requiring consideration of not only survival benefit but also quality of life issues. We reported that most patients received eribulin (E) in 1st- or 2nd- line therapy in the Japanese real-world setting at the ESMO 2018 congress. Here, we report updated data regarding ChT sequences and treatment discontinuation.

Methods

We prospectively registered TN AMBC patients and estrogen receptor-positive and HER2-negative AMBC patients who relapsed during or within 6 months after the end of adjuvant endocrine therapy (ET) and were refractory to at least one previous ET. Patterns of ChT and their feasibility were evaluated (ClinicalTrials.gov No. NCT02551263).

Results

Between June 2015 and July 2017, a total of 201 patients were enrolled, 180 of whom were analyzed. The frequent 1st- and 2nd-line ChT sequences were as follows: T followed by E (n=33), oral FU-based therapy (FU) followed by E (n=26), E followed by T (n=21), T followed by FU (n=11), and E followed by FU (n=10). E was administered in 1st- or 2nd-line therapy for 60 patients who did not receive A, and for 35 patients who did not receive T. The main reason the attending physician chose E for patients who did not receive A was “reducing toxicity” in 38.3%, “non-life threatening” in 30.0%, and “patient preference” in 18.3%. Respective ratios in patients who did not receive T were 34.3%, 34.3%, and 20.0%. Patients treated with E or FU in 1st- and 2nd-line ChT had significantly less discontinuation due to adverse events than those with A/T (1st line: p=0.011, 2nd-line: p=0.036). In contrast, there was no statistical difference between E/FU and A/T in 3rd-line ChT (p=1.000).

Conclusions

This study showed that various 1st- and 2nd-sequence treatments including E were chosen in a real-world setting. The lower proportion of adverse events and lower discontinuation rate of E/FU in 1st- and 2nd-line therapy may be due to the better feasibility of these treatments.

Clinical trial identification

NCT02551263.

Editorial acknowledgement

Legal entity responsible for the study

Kyoto Breast Cancer Research Network.

Funding

Eisai Co., Ltd.

Disclosure

T. Kagimura: Research grant/Funding (self): Eisai. T. Taguchi: Honoraria (self), Donation: Eisai. All other authors have declared no conflicts of interest.