Patients with HR+/HER2- Metastatic Breast Cancer Treated with CDK4/6 Inhibitors: A Real-World Study in Italy

Figures & data

Table 1. Demographic parameters of the included patients before propensity score matching.

Variables	Palbociclib, n = 2878	Abemaciclib, n = 478	Ribociclib, n = 1083
Age at index date, years, mean ± standard deviation	64.0 ± 11.8	62.5 ± 11.9	61.3 ± 11.8
Age groups, n (%)
18–39 years	53 (1.8%)	11 (2.3%)	31 (2.9%)
40–49 years	293 (10.2%)	67 (14%)	164 (15.1%)
50–59 years	704 (24.5%)	114 (23.8%)	273 (25.2%)
60–69 years	796 (27.7%)	137 (28.7%)	324 (29.9%)
70–79 years	770 (26.8%)	118 (24.7%)	230 (21.2%)
≥80 years	262 (9.1%)	31 (6.5%)	61 (5.6%)

Continuous variables are given as the mean ± standard deviation, and categorical variables are given as numbers and percentages in brackets.

Table 2. Clinical and past medical history of the included patients before propensity score matching.

Variables	Palbociclib, n = 2878	Abemaciclib, n = 478	Ribociclib, n = 1083
Concomitant diseases at baseline, n (%)
Diabetes	337 (11.7%)	49 (9.6%)	117 (10.8%)
Hypertension	1,611 (56%)	250 (52.3%)	546 (50.4%)
Cardiovascular disease	115 (4%)	14 (2.9%)	31 (2.9%)
COPD	501 (17.4%)	61 (12.8%)	152 (14%)
Arthritis	8 (0.3%)	NI	6 (0.6%)
Osteoporosis	687 (23.9%)	98 (20.5%)	148 (13.7%)
Previous breast cancer-related hospitalizations, n (%)	1405 (48.8%)	213 (44.6%)	434 (40.1%)
Previous surgery, n (%)	1899 (66%)	315 (65.9%)	758 (70%)
Previous metastases reported in the database, n (%)	2000 (69.5%)	376 (78.7%)	846 (78.1%)
Follow-up, months, mean ± standard deviation	22.2 ± 14.6	11.5 ± 8.3	16.2 ± 10.9

Continuous variables are given as the mean ± standard deviation, and categorical variables are given as numbers and percentages in brackets.

COPD: Chronic obstructive pulmonary disease; NI: Not issuable (for data privacy).

Table 3. Distribution of patients, expressed as numbers and percentages, in the three cohorts according to the year of inclusion and by line of treatment.

Year	Palbociclib, n = 2878		Abemaciclib, n = 478		Ribociclib, n = 1083
	1L	2L+	1L	2L+	1L	2L+
2017	124 (62.3%)	75 (37.7%)	0 (0%)	0 (0%)	0 (0%)	0 (0%)
2018	653 (67.8%)	310 (32.2%)	0 (0%)	0 (0%)	22 (64.7%)	12 (35.3%)
2019	595 (75.1%)	197 (24.9%)	25 (71.4%)	10 (28.6%)	289 (83.8%)	56 (16.2%)
2020	423 (75.7%)	136 (24.3%)	169 (79.7%)	43 (20.3%)	285 (81.4%)	65 (18.6%)
2021	301 (83.6%)	59 (16.4%)	180 (87.4%)	26 (12.6%)	297 (87.1%)	44 (12.9%)
2022 ^†	5 (100%)	0 (0%)	21 (84%)	4 (16%)	13 (100%)	0 (0%)

† Referred to the 6-month period January 2022–June 2022 (only a part of the Italian healthcare entities involved in the analysis have data available during 2022).

Percentages computed on the overall number of patients (1L and 2L+) for each year combination of year of inclusion and cohort.

1L: First line; 2L+: Second line or subsequent.

Table 4. Distribution of concomitant endocrine therapy (presented as numbers and percentages) in palbociclib, abemaciclib and ribociclib cohorts stratified by menopausal status.

Variables	Palbociclib, n = 2878	Abemaciclib, n = 478	Ribociclib, n = 1083
Premenopausal status	611 (21.2%)	110 (23%)	297 (27.4%)
Fulvestrant	356 (58.3%)	61 (55.5%)	62 (20.9%)
Aromatase inhibitor	229 (37.5%)	41 (37.3%)	221 (74.4%)
Tamoxifen	NI	0 (0%)	NI
Postmenopausal status	2267 (78.8%)	368 (77%)	786 (72.6%)
Fulvestrant	1251 (55.2%)	171 (46.5%)	194 (24.7%)
Aromatase inhibitor	886 (39.1%)	166 (45.1%)	531 (67.6%)
Tamoxifen	NI	0 (0%)	NI

NI: Not issuable due to privacy (≤3 patients).

Figure 1. Mean daily dosing of CDK4/6 inhibitors prescribed.

CDK4/6 inhibitors prescribed (A) at the index date; (B) by 3 months among patients with at least 3 months of treatment; (C) by 6 months among patients with at least 6 months of treatment.

*Label-recommended daily dose.

NI: Not issuable due to privacy (≤3 patients).

Table 5. Demographic parameters of the included patients after propensity score matching.

Variables	Palbociclib, n = 478	Abemaciclib, n = 478	Ribociclib, n = 478	Standardized mean difference
Age at index date, years, mean ± standard deviation	62.9 ± 11.3	62.5 ± 11.9	62.1 ± 11.9	0.044
Age groups, n (%)
18–39 years	5 (1%)	11 (2.3%)	15 (3.1%)
40–49 years	57 (11.9%)	67 (14%)	64 (13.4%)
50–59 years	142 (29.7%)	114 (23.8%)	116 (24.3%)
60–69 years	120 (25.1%)	137 (28.7%)	142 (29.7%)
70–79 years	122 (25.5%)	118 (24.7%)	108 (22.6%)
≥80 years	32 (6.7%)	31 (6.5%)	33 (6.9%)

Continuous variables are given as the mean ± standard deviation, and categorical variables are given as numbers and percentages in brackets.

Table 6. Clinical and past medical history of the included patients after propensity score matching.

Variables	Palbociclib, n = 478	Abemaciclib, n = 478	Ribociclib, n = 478	Standardized mean difference
CCI (mean ± standard deviation)	0.5 ± 0.7	0.5 ± 0.7	0.5 ± 0.7	0.022
0, n (%)	292 (61.1%)	285 (59.6%)	285 (59.6%)
1, n (%)	147 (30.8%)	154 (32.2%)	161 (33.7%)
≥2, n (%)	39 (8.2%)	39 (8.2%)	32 (6.7%)
Previous breast cancer-related hospitalizations, n (%)	225 (47.1%)	213 (44.6%)	226 (47.3%)	0.036
Previous surgery, n (%)	311 (65.1%)	315 (65.9%)	306 (64%)	0.027
Previous metastases reported in the database, n (%)	370 (77.4%)	376 (78.7%)	375 (78.5%)	0.020
Follow-up, months, mean ± standard deviation	22.3 ± 14.9	11.5 ± 8.3	15.7 ± 10.7	0.614

Continuous variables are given as the mean ± standard deviation, and categorical variables are given as numbers and percentages in brackets.

CCI: Charlson comorbidity index.

Figure 2. Kaplan–Meier curves for time to treatment discontinuation in patients on treatment at each time point for palbociclib, abemaciclib and ribociclib groups after propensity score matching.

(A) Total patients receiving combined therapy with CKD4/6 and endocrine therapy, (B) patients receiving combined therapy with CKD4/6 plus fulvestrant; (C) patients receiving combined therapy with CKD4/6 plus aromatase inhibitors.

CKD4/6i: CDK4/6 inhibitor; TTD: Time to treatment discontinuation.

Data sharing statement

All data used for the current study are available upon reasonable request to CliCon S.R.L.