Table 1 Patient demographic and baseline characteristics

Median age, years (range)

60.5 (29–84)

59.0 (41–78)

60.0 (29–84)

Race, n (%)

  Black or African American

0

1 (2.0)

1 (1.0)

  Asian

1 (1.9)

0

1 (1.0)

  Native Hawaiian or other Pacific Islander

1 (1.9)

0

1 (1.0)

  White

44 (84.6)

41 (80.4)

85 (82.5)

  Missing

6 (11.5)

9 (17.6)

15 (14.6)

ECOG PS, n (%)

  0

38 (73.1)

30 (58.8)

68 (66.0)

  1

14 (26.9)

21 (41.2)

35 (34.0)

Menopausal status, n (%)

  Premenopausal

1 (1.9)

4 (7.8)

5 (4.9)

  Postmenopausal

50 (96.2)

47 (92.2)

97 (94.2)

  Missing

1 (1.9)^a

0

1 (1.0)^a

Bone-only metastases at screening, n (%)

  No

13 (25.0)

19 (37.3)

32 (31.1)

  Yes

38 (73.1)

32 (62.7)

70 (68.0)

  Missing

1 (1.9)^a

0

1 (1.0)^a

Previous systemic chemotherapy in metastatic setting, n (%)

6 (11.5)

3 (5.9)

9 (8.7)

Previous fulvestrant treatment,^b n (%)

26 (50.0)

19 (37.3)

45 (43.7)

Previous CDK4/6 inhibitor,^b n (%)

39 (75.0)

39 (76.5)

78 (75.7)

Endocrine resistance,^c n (%)

  Primary

15 (28.8)

12 (23.5)

27 (26.2)

  Secondary

37 (71.2)

39 (76.5)

76 (73.8)