Patient preferences for frontline therapies for Philadelphia chromosome-positive acute lymphoblastic leukemia: a discrete choice experiment

Figures & data

Table 1. Final attributes and levels included in the discrete choice experiment.

Attribute	Definition	Levels
Overall survival	Number of months of expected survival after starting treatment, including the time in remission and the time when no longer in remission.	Variant A: 30, 35, 40, 45, 50, 55, 60 Variant B: 60, 65, 70, 75, 80, 85, 90
Duration of remission	Number of months after achieving remission that participant can expect to remain in remission. Remission achieved 3 months after starting treatment.	Variant A: 15, 20, 25, 30, 35, 40, 45 Variant B: 45, 50, 55, 60, 65, 70, 75
Major CV events	Percentage of risk of experiencing a major CV event requiring hospitalization (e.g., heart attack, stroke). In rare cases, they are fatal.	Both variants: 0%, 25%, 50%
Myelosuppression	Percentage of risk of suppressed immune system during the first 6 months of treatment. Symptoms: feeling tired, shortness of breath, getting infections more easily (potentially requiring hospitalization), fever, increased bruising, bleeding more easily. After 6 months, less intensive treatment required (maintenance phase) and participant will not experience these symptoms.	Both variants: 0%, 50%, 100%

Attribute definitions were provided to patients before starting the survey. Definitions shown are shortened versions of the actual wording used.

CV: Cardiovascular.

Figure 1. Example discrete choice experiment task.

CV: Cardiovascular; TKI: Tyrosine kinase inhibitor.

Table 2. Patient demographics and baseline characteristics in the main survey.

Characteristic	Value (n = 201)
Gender, n (%)
Male	121 (60)
Female	80 (40)
Age (years), mean ± SD	44.8 ± 12.9
Racial background, n (%)
White	130 (65)
Black or African–American	19 (9)
Asian	12 (6)
Hispanic or Latinx	39 (19)
Other	4 (2)
Not reported	10 (5)
Education level, n (%)
Elementary/primary school	0 (0)
High school	22 (11)
Some college	44 (22)
College degree	79 (39)
Postgraduate degree	56 (28)
Remission status^†, n (%)
Just started treatment	33 (16)
Not achieved remission	25 (12)
In remission	102 (51)
Achieved remission but have since relapsed	38 (19)
Have previously relapsed but now back in remission	32 (16)
Relapses, n (%)
None	104 (52)
1	62 (31)
2–3	31 (15)
>3	4 (2)
Ph+ ALL-related ER visits in past year, mean ± SD	1.5 ± 1.8
Ph+ ALL diagnosis, n (%)
<3 months ago	12 (6)
3–6 months ago	31 (15)
6–12 months ago	42 (21)
>12 months ago	116 (58)
Past treatments for Ph+ ALL, n (%)
0	16 (8)
1	52 (26)
2–3	58 (29)
4–5	21 (10)
>5	54 (27)
Current treatments for Ph+ ALL, n (%)
0	25 (12)
1	113 (56)
2–3	45 (22)
>3	18 (9)
Current TKIs, n (%)
Dasatinib	48 (24)
Imatinib	36 (18)
Ponatinib	17 (8)
Nilotinib	13 (6)

† Not mutually exclusive. ‘Not achieved remission’ could not be selected with ‘In remission’ or ‘have previously relapsed but now back in remission.’

ER: Emergency room; Ph+ ALL: Philadelphia chromosome-positive acute lymphoblastic leukemia; SD: Standard deviation; TKI: Tyrosine kinase inhibitor.

Figure 2. Preference weights.

Discrete choice experiment preference data collected from the main survey were analyzed using a linear multinomial logit model. Preferences for changes in the attributes are expressed as part-worth utilities. Markers indicate maximum likelihood estimates, and the bars indicate 95% CI.

CV: Cardiovascular; DOR: Duration of remission; OS: Overall survival.

Figure 3. Maximal acceptable risk of cardiovascular vevent.

CV: Cardiovascular; DOR: Duration of remission; OS: Overall survival.

Figure 4. Preference heterogeneity.

Maximum acceptable CV risk for 1 month additional OS by participant subgroups.

CV: Cardiovascular; ER: Emergency room; MAR: Maximum acceptable risk; OS: Overall survival; Ph+ ALL: Philadelphia chromosome-positive acute lymphoblastic leukemia; y: Year.

Table 3. Patient preferences from the qualitative interviews (n = 5).

Choice task presented	Preference (n/N)	Sample quotations
(A) 55-month remission, 75-month OS, 50% risk of myelosuppression, 50% risk of major CV event vs (B) 50-month remission, 65-month OS, 50% risk of myelosuppression, 25% risk of major CV event	Prioritized survival (2/5)	“[T]o be honest, I’m just basing this information of the total of months that I can be alive. Then I can deal with the side effects” (US002) “Okay, well the first thing I look at is which one has the longer OS and that was 75 months. The bottom one is 65 months So, we're talking an additional ten months…So, I think ten months is worth it, […] I’m going to try to have a higher opportunity for a longer survival.” (US003)
	Prioritized avoiding CV risk (3/5)	“[T]he cardiac event is…really worries me, that’s 50% or 50 people have experienced a cardiac event. So, I would probably choose the 10 months shorter of life […] If I had a stroke or a heart attack […] there’s just more […] things that I would not be able to do with the remainder of time that I have left.” (US001) “The cardio risk is scary […] I worry about the […] stroke event […] because I know people who have had strokes and it's not fun.” (US005)
(A) 55-month remission, 75-month OS, 50% risk of myelosuppression, 25% risk of major CV event vs (B) 50-month remission, 65-month OS, 0% risk of myelosuppression, 25% risk of major CV event	Prioritized survival (2/5)	“I would probably choose treatment A as I would live longer, I mean, suppressed immune system doesn’t bother me as much as cardiac events I’d rather live longer and have a suppressed immune system than live shorter and not have…” (US001) On mitigating suppressed immune system risk: “Well, there’s ways… there’s like taking extra vitamin C, […], there’s over the counter medications that can help build up your immune system, wearing a mask out in public, […] keeping hand sanitizer on you, washing your hands constantly. So, there’s ways to increase your immune system and prevent any colds or anything like that from happening.” (US001)
	Prioritized avoiding myelosuppression risk (3/5)	“I’m not going to take ten months for a risk of the suppressing my immune system, against not being, it’s not worth ten months ever.” (US003)
(A) 55-month remission, 75-month OS, 100% risk of myelosuppression, 50% risk of CV event vs (B) 50-month remission, 65-month OS, 50% risk of myelosuppression, 25% risk of CV event	Prioritized avoiding risks (5/5)	“I am going to be hospitalized and very sick. I can’t take that offer. I can’t take that chance. It’s not worth it, especially for ten months.” (US003) “[T]he suppressed immune system, that’s very bad […] if I had that you got to be very careful […] I would definitely not leave the house you know, […] I could walk down the street and catch something…” (US005)

CV: Cardiovascular; OS: Overall survival.