Table 1.

Patient characteristics at baseline.

Characteristics	Number of cases (%)
Age (years)
Median (range)	53 (30–73)
Hormone receptor status
ER+/PR+	42 (95.5%)
ER+/PR-	2 (4.5%)
Menopausal status
Postmenopausal	23 (52.3%)
Premenopausal	21 (47.7%)
Disease-free survival (months)
Median (range)	28.5 (0–144)
De novo	13 (29.5%)
≤24	8 (18.2%)
>24	23 (52.3%)
Number of metastatic sites
1	6 (13.6%)
2	12 (27.3%)
≥3	26 (59.1%)
Metastatic site
Bone	28 (63.6%)
Viscera	34 (77.3%)
Liver	25 (56.8%)
Lung	24 (54.5%)
Brain	4 (9.1%)
Lines of previous therapy of CDK4/6i
1	9 (20.5%)
2	7 (15.9%)
≥3	28 (63.6%)
Benefits of CDK4/6 Inhibitor
Benefits	27 (61.4%)
No benefits	17 (38.6%)
Number of therapy between CDK4/6i and tucidinostat
Median (range)	1 (0–7)
0	7 (15.9%)
1	22 (50.0%)
2	6 (13.6%)
≥3	9 (20.5%)
Previous endocrine therapy in the metastatic setting
Tamoxifen or toremifene	8 (18.2%)
Letrozole or anastrozole	29 (65.9%)
Exemestane	17 (38.6%)
Fulvestrant	34 (77.3%)
Everolimus	5 (11.4%)
Sensitivity to prior hormonal therapy
Yes	39 (88.6%)
No	5 (11.4%)
Endocrine partner of Tucidinostat
Tamoxifen or toremifene	5 (11.4%)
Letrozole or anastrozole	8 (18.2%)
Exemestane	19 (43.2%)
Fulvestrant	10 (22.7%)
Medroxyprogesterone	2 (4.5%)
Number of previous chemotherapy for MBC
Median (range)	2 (0–7)
0	2 (4.5%)
1	10 (22.7%)
2	13 (29.5%)
≥3	19 (43.2%)
Previous chemotherapy
(Neo)adjuvant only	2 (4.5%)
Metastatic ± (neo)adjuvant	42 (95.5%)
Number of previous endocrine therapy for MBC
Median (range)	2 (1–5)
1	11 (25.0%)
2	17 (38.6%)
≥3	16 (36.4%)
Number of previous therapy for MBC
Median (range)	5 (1–15)
1	1 (2.3%)
2	6 (13.6%)
≥3	37 (84.1%)