Oncologist and Patient Preferences for Attributes of CDK4/6 Inhibitor Regimens for the Treatment of Advanced/Metastatic HR Positive/HER2 Negative Breast Cancer: Discrete Choice Experiment and Best–Worst Scaling

Figures & data

Table 1 Attributes and Levels Included in the DCE

Attribute	Definition	Levels
Safety-Related Attributes
Risk of dose reduction due to AEs	[INSERT LEVEL] risk of lowering treatment dose due to side effects	36% 43% 45%
Risk of diarrhea	[INSERT LEVEL] risk of diarrhea with a [INSERT LEVEL] chance of severe diarrhea (increase of seven or more loose or watery stools per day which requires hospitalization)	81%, 9% 35%, 1% 26%, 1%
Risk of abdominal (belly) pain	[INSERT LEVEL] risk of abdominal (belly) pain, with [INSERT LEVEL] chance of severe abdominal pain	29%, 1% 17%, 1% 11%, 1%
Need for ECG monitoring to assess heart function	Requires ECG testing to assess heart function 3 times within the first 3 months of treatment to monitor the 6% risk of arrhythmia Do not require ECG testing to assess heart function	yes no
Risk of Grade 3/4 neutropenia	[INSERT LEVEL] chance you will develop low white blood cell counts during treatment that may not cause symptoms, but may result in a [INSERT LEVEL] risk of a serious infection	22%, 4% 60%, 1% 66%, 5%
Non-Clinical Attributes
Regimen	[INSERT LEVEL]	2 pills per day taken with food 3 pills per day taken with or without food 4 pills per day taken with or without food
Dosing schedule	[INSERT LEVEL]	Pills taken everyday Stop taking 1 pill for 7 days per month Stop taking 3 pills for 7 days per month

Abbreviations: AE, adverse event; ECG, electrocardiogram.

Table 2 Sample Characteristics

Oncologist Variables		N	%
Practice Location	Major metropolitan/urban area	132	63.2
	Suburb/small city	70	33.5
	Rural/small town	7	3.3
Primary Specialty	Medical oncology	172	82.3
	Hematology oncology	37	17.7
		Mean	SD
Years in Practice		15.75	6.67
Median (IQR)		15.0	10.0, 20.0
Percent of Time Spent in Direct Patient Care		93.33	6.78
Median (IQR)		95.0	90.0, 100.0
Percent of Time in Practice Setting	Community-based solo or group practice	44.95	44.73
	Median (IQR)	40.0	0.0, 100.0
	Out-patient oncology center or clinic	22.39	36.81
	Median (IQR)	0.0	0.0, 30.0
	Academically-based practice	23.06	38.69
	Median (IQR)	0.0	0.0, 25.0
	NCCN designated cancer center	9.17	27.08
	Median (IQR)	0.0	0.0, 0.0
	Other setting	0.43	2.78
	Median (IQR)	0.0	0.0, 0.0
Number of Patients with mBC Seen/Treated in Past 3 Months		71.24	24.83
Median (IQR)		75.0	50.0, 99.0
Percent of Time Treating Patients with mBC		57.76	28.60
Median (IQR)		60.0	30.0, 80.0
Number of Patients with HR+/HER2- mBC		41.64	21.79
Median (IQR)		40.0	24.0, 60.0
Number of Patients with HR+/HER2- mBC on Systemic Treatment		36.53	19.83
Median (IQR)		34.0	20.0, 50.0
Patient Variables		N	%
Education	Some high school/high school graduate	55	18.1
	Some college or higher	249	81.9
Marital Status	Single/separated/divorced/widowed	114	37.5
	Married/committed relationship	190	62.5
Employment Status	Unemployed/retired	155	51.0
	Employed	130	42.8
	Other	19	6.3
Household Income	<$50,000	144	47.4
	≥$50,000	149	49.0
	Prefer not to answer	11	3.6
Race/Ethnicity	African-American/Black	64	21.1
	Asian	22	7.2
	American Indian	39	12.8
	Hispanic	70	23.0
	White	192	63.2
First Diagnosed with Breast Cancer	In the last year/past 12 months	25	8.3
	1 to 2 years ago	71	23.4
	>2 years, but <5 years ago	119	39.3
	≥5 years ago	88	29.0
		Mean	SD
Age		47.35	9.96
Median (IQR)		47.0	40.0, 55.0
Number of months from initial diagnosis when breast cancer reached advanced/metastatic stage		21.34	21.80
Median (IQR)		15.0	8.0, 26.5

Notes: For patient race/ethnicity, the total sums to >100% because multiple options could be selected.

Abbreviations: HR+/HER2-, hormone receptor positive/HER2 negative; IQR, interquartile range; mBC, metastatic breast cancer; NCCN, National Comprehensive Cancer Network; SD, standard deviation.

Figure 1 Attribute-level preference weights for oncologists and patients.

Abbreviations: AE, adverse event; ECG, electrocardiogram.

Table 3 Preferences Among Oncologists and Patients for Selected CDK4/6i Treatment Profiles

Attribute	Levels	Palbociclib + AI	Abemaciclib+ AI	Ribociclib+ AI
Oncologist Preferences
Risk of dose reduction due to AEs	36%	0.10
	43%		−0.03
	45%			−0.07
Risk of diarrhea	26% (1% severe diarrhea)	1.04		1.04
	35% (1% severe diarrhea)
	81% (9% severe diarrhea)		−1.39
Risk of abdominal (belly) pain	11% (1% severe diarrhea)	0.25		0.25
	17% (1% severe diarrhea)
	29% (1% severe diarrhea)		−0.41
Need for ECG monitoring to assess heart function	No	0.52	0.52
	Yes			−0.52
Risk of Grade 3/4 neutropenia	22% (4% serious infection)		0.86
	60% (1% serious infection)			−0.02
	66% (5% serious)	−0.84
Regimen	2 pills per day taken with food	0.06
	3 pills per day taken with or without food		0.02
	4 pills per day taken with or without food			−0.08
Dosing schedule	Pills taken everyday		0.26
	Stop taking 1 pill for 7 days per month	−0.16
	Stop taking 3 pills for 7 days per month			−0.10
Total profile utility		0.97	−0.17	0.50
Patient Preferences
Risk of dose reduction due to AEs	36%	0.24
	43%		−0.03
	45%			−0.21
Risk of diarrhea	26% (1% severe diarrhea)	0.74		0.74
	35% (1% severe diarrhea)
	81% (9% severe diarrhea)		−1.16
Risk of abdominal (belly) pain	11% (1% severe abdominal pain)	0.29		0.29
	17% (1% severe abdominal pain)
	29% (1% severe abdominal pain)		−0.36
Need for ECG monitoring to assess heart function	No	0.26	0.26
	Yes			−0.26
Risk of Grade 3/4 neutropenia	22% (4% serious infection)		0.99
	60% (1% serious infection)			−0.14
	66% (5% serious infection)	−0.85
Regimen	2 pills per day taken with food	0.17
	3 pills per day taken with or without food		0.03
	4 pills per day taken with or without food			−0.20
Dosing schedule	Pills taken everyday		0.15
	Stop taking 1 pill for 7 days per month	−0.10
	Stop taking 3 pills for 7 days per month			−0.05
Total profile utility		0.75	−0.12	0.17

Abbreviations: AE, adverse event; AI, aromatase inhibitor; ECG, electrocardiogram.

Figure 2 BWS exercise ratings for oncologists and patients.

Note: An asterisk *Indicates that groups significantly differ at p<0.05.

Abbreviation: ECG, electrocardiogram.