Outcome Notes
ADVERSE EVENTS
See Baseline demographic and clinical characteristics.Data are median (range) or 
Abbreviation: DFS: disease-free survival.Treatment exposure and dose modifications.Data are mean (SD) or 
Summary of adverse events.Efficacy outcomes of progression-free survival (PFS) in the FAS population. (Efficacy outcomes of progression-free survival (PFS) as classified by the patients. (Kaplan-Meier survival curves of PFS in the sensitivity analysis. During the whole treatment period, the 3-week schedule of Kaplan-Meier survival curves of overall survival (OS). The median OS was 28.0 (95% CI, 21.4-34.6) months in the 3-week arm and 25.8 (95% CI, 17.3-34.3) months in the 4-week arm. There was no significant OS difference between the 2 arms (HR = 1.04; 95% CI, 0.58-1.89; Schedule modification is a common strategy in clinical oncology to optimize the therapeutic index of established cytotoxic agents. The present head-to-head randomized phase II study in HER2-negative mBC demonstrated a better efficacy and more favorable safety profile for the 3-week Several clinical trials have investigated alternative There was no OS benefit in the 3-week regimen compared with the 4-week arm, which might be attributed to the complex situation of the treatment of mBC. In addition, patient compliance, endocrine sensitivity, and subsequent maintenance treatments may affect OS to a large extent. Consistently, the ORR (51.1% vs. 48.9%) and DCR (93.6% vs. 80.9%) also exhibited no notable differences between the 2 arms. Our results were generally comparable with the data from a previous trial reported by Tamura et al,The 3-week schedule was investigated in the hope of providing a better safety profile to the patients. Consistently, here, the 3-week schedule of Several limitations of the present study should be recognized. First, this analysis was based on a small sample, which may have led to a hidden bias. Second, a small proportion of patients in the 2 arms had delayed treatment because of the COVID-19 pandemic, which might have affected the interpretation of the efficacy results. However, the calculated RDI data showed that the patients in 2 arms comparability received more than 80% of the planned dose intensities because of the prophylactic use of G-CSF, and this RDI level also ensured the anticipated efficacy well.In summary, this study demonstrated the better safety profile and anti-cancer activity of the 3-week schedule of 