Usability of mepolizumab single-use prefilled autoinjector for patient self-administration

Figures & data

Figure 1. Summary of patient disposition (AP population). *The electronic case report form did not allow a reason for prescreen failure to be defined. ^†Including protocol-defined continuation criteria. Prescreen failure includes any patient who was assigned a patient number but did not complete any screening procedures. Screen failure includes any patient who completed at least one screening procedure, but the patient/caregiver did not attempt to self-administer a dose of mepolizumab via an AI. Study completion includes any patient who completed all assessments at the end of study visit. Two patients were withdrawn from the study after self-administering their first dose of mepolizumab; one patient owing to serious AEs relating to a traffic accident and one patient owing to physician decision (failure to comply with study procedures and unreliability). AE: adverse event; AI: autoinjector; AP: all patients enrolled.

Table 1. Demographics and baseline characteristics (APT population).

	Mepolizumab AI (N = 159)
Females, n (%)	98 (62)
Age (years)*
Mean (SD)	49.3 (16.18)
Range	12, 77
Age group (years), n (%)
12–17	11 (7)
18–64	122 (77)
≥65	26 (16)
BMI (kg/m^2), mean (SD)^†	31.4 (7.61)
Ethnicity, n (%)
White	127 (80)
African-American	25 (16)
Asian	6 (4)
Other^‡	1 (<1)
Disease duration (years)
Mean (SD)	23.3 (16.47)
Range	2, 68
Patients not currently receiving mepolizumab, n (%)	75 (47)

*Birth day and month is imputed with June 30.

^†BMI was collected for 158 patients.

^‡No suitable race category was available in the electronic case report form for this patient.

AI: autoinjector; APT: all patients treated; BMI: body mass index; SD: standard deviation.

Table 2. Summary of injection success including observer and at-home checklists (APT population).

Dose interval	Mepolizumab AI with pictogram (N = 104) Number of patients, n (%) [95% CI]	Mepolizumab AI without pictogram (N = 55) Number of patients, n (%) [95% CI]
Week 0, first dose (injection observed, in-clinic)
Attempted injections	104 (100)	55 (100)
Successful injections*	101 (97) [92, 99]	52 (95) [85, 99]
Observer checklist completed	103	53
Steps completed with some difficulty or repeated references to IFU
Expiration date checked	1 (<1)	6 (11)
Inspection window checked	–	2 (4)
Removed clear needle cap	3 (3)	2 (4)
Injected within 5 minutes of removing needle cap	–	1 (2)
AI positioned straight on injection site with yellow needle guard flat on skin	–	1 (2)
AI pushed all the way down and held^†^,^‡	–	5 (9)
AI kept in position and pushed all the way down until full dose administered^†^,^§	1 (<1)	2 (4)
Week 4, second dose (injection unobserved at home)
Attempted injections	103 (99)	54 (98)
Successful injections*	101 (98) [93, 100]	52 (96) [87, 100]
At-home checklist completed	102	53
Steps completed with some difficulty or repeated references to IFU
Expiration date checked	2 (2)	–
Inspection window checked	–	1 (2)
Injected within 5 minutes of removing needle cap	1 (<1)	–
AI pushed all the way down and held^†^,^‡	1 (<1)	1 (2)
AI kept in position and pushed all the way down until full dose administered^†^,^‡	2 (2)	2 (4)
Week 8, third dose (injection observed, in-clinic)
Attempted injections	103 (99)	54 (98)
Successful injections*	102 (99) [95, 100]	53 (98) [90, 100]
Observer checklist completed	102	52
Steps completed with some difficulty or repeated references to IFU
Expiration date checked	5 (5)	1 (2)
Inspection window checked	5 (5)	–
Removed clear needle cap	–	1 (2)
AI positioned straight on injection site with yellow needle guard flat on skin	1 (<1)	–
AI pushed all the way down and held^†	–	1 (2)
Weeks 4 and 8
Attempted injections	103 (99)	54 (98)
Successful injections*	100 (97) [92, 99]	51 (94) [85, 99]
Weeks 0, 4, and 8
Attempted injections	103 (99)	54 (98)
Successful injections*	98 (95) [89, 98]	48 (89) [77, 96]

*Denominator was the number of patients/caregivers attempting an injection at that visit(s). Reasons for unsuccessful injection at Week 0 in the AI with pictogram group were injecting into the upper arm (n = 2) and AI pulled away before end of injection/evidence of liquid leaking from injection site (n = 1). One patient failed both the Week 0 and Week 4 injections due to use of an incorrect injection site (upper arm). Reasons for unsuccessful injection at Week 0 in the AI without pictogram group were: AI pulled away before end of injection (n = 2) and evidence of liquid leaking from the injection site (n = 1).

^†Critical injection step.

^‡One patient in the AI with pictogram group did not complete this step.

^§One patient in the AI with pictogram group and one patient in the AI without pictogram group did not complete this step.

AI: autoinjector; APT: all patients treated; IFU: instructions for use.

Table 3. Patient/caregiver perception of AI usability (APT population).

	Mepolizumab AI with pictogram	Mepolizumab AI without pictogram
	(N = 104)	(N = 55)
	Number of patients, n (%)	Number of patients, n (%)
Ease to self-administer using AI at home	102^†	51^‡
How easy was it to give yourself an injection using the pen at home?*
Not at all	0	0
A little	2 (2)	2 (4)
Moderately	6 (6)	5 (10)
Very	34 (33)	18 (35)
Extremely	60 (59)	26 (51)
Confidence at study completion in ability to use AI at home	102	51
At the end of the study, how confident were you about your ability to use the pen in the correct way on your own when you were not at the doctor’s office?
Not at all	1 (<1)	0
A little	1 (<1)	1 (2)
Moderately	2 (2)	5 (10)
Very	23 (23)	17 (33)
Extremely	75 (74)	28 (55)
Anxiety felt about self-administering mepolizumab using the AI at home	102	51
How anxious did you feel about administering mepolizumab using the pen at home?
Not at all	55 (54)	36 (71)
A little	21 (21)	10 (20)
Moderately anxious	18 (18)	3 (6)
Very anxious	3 (3)	0
Extremely anxious	5 (5)	2 (4)
Preferred injection site	102	51
Which injection site did you prefer?
Upper thigh	54 (53)	28 (55)
Abdomen	48 (47)	23 (45)

*The AI was referenced as the “pen” in the device usability/functionality questionnaire.

^†Of those patients who injected themselves correctly at Week 8 (n = 102) 93/101 (92%) responded it was “very” or “extremely” easy to give themselves an injection using the AI at home. One patient injected themselves correctly at Week 8 but did not complete the device usability/functionality questionnaire.

^‡Of those patients who injected themselves correctly at Week 8 (n = 53) 43/50 (86%) responded it was “very” or “extremely” easy to give themselves an injection using the AI at home. Three patients injected themselves correctly at Week 8 but did not complete the device usability/functionality questionnaire.

AI: autoinjector; APT: all patients treated.

Figure 2. Mean plasma mepolizumab concentration-time plots (C_trough) by baseline mepolizumab use (APT population). Data are presented as mean ± SD. Lower limit of quantification was 50 ng/mL. APT: all patients treated; SD: standard deviation.

Figure 3. Absolute blood eosinophils by baseline mepolizumab use (PD population). Data are presented as geometric mean ± 95% CI. CI: confidence interval; PD: pharmacodynamic.

Table 4. Adverse events (APT population).

	Mepolizumab AI (N = 159) Number of patients, n (%)
Any on-treatment AE	56 (35)
Drug-related*	5 (3)
Led to discontinuation of study treatment and/or withdrawal from the study	1 (<1)
Common on-treatment AEs^†
Nasopharyngitis	9 (6)
Headache	8 (5)
Upper respiratory tract infection	6 (4)
Lower respiratory tract infection	5 (3)
Urinary tract infection	5 (3)
Any on-treatment SAE	4 (3)
Non-fatal	4 (3)
Any posttreatment AE	5 (3)
Any AE of special interest
Systemic reactions	1 (<1)
Other systemic reactions	1 (<1)
Local injection site reactions	5 (3)
Infections	31 (19)
Opportunistic infections	1 (<1)

*As judged by the investigator.

^†Occurring in ≥3% of patients.

AE: adverse event; AI: autoinjector; APT: all patients treated; SAE: serious adverse event.

Table 5. Injection pain summary (APT population).

Dose interval	Mepolizumab AI (N = 159) Number of patients, n (%)
	Time following self-administration
	Immediately	1 h	24 h
Week 0, first dose, n	141	140	136
Patients experiencing any pain (VAS score >0)	85 (60)	51 (36)	30 (22)
Pain greater than expected	12 (14)	4 (8)	2 (7)
Pain acceptable*	85 (100)	51 (100)	30 (100)
VAS score, n
Mean (SD)	10.5 (17.09)	3.3 (8.43)	1.8 (5.79)
Median	3.0	0.0	0.0
Range	0, 70	0, 51	0, 41
Week 4, second dose, n	129	109	134
Patients experiencing any pain (VAS score >0)	73 (57)	32 (29)	33 (25)
Pain greater than expected	9 (12)	5 (16)	6 (18)
Pain acceptable*	72 (99)	32 (100)	31 (94)
VAS score, n
Mean (SD)	8.4 (16.58)	3.7 (12.29)	2.3 (8.08)
Median	2.0	0.0	0.0
Range	0, 100†	0, 100^†	0, 70
Week 8, third dose, n	150	130	116
Patients experiencing any pain (VAS score >0)	65 (43)	27 (21)	18 (16)
Pain greater than expected	13 (20)	2 (7)	0
Pain acceptable*	65 (100)	27 (100)	18 (100)
VAS score
Mean (SD)	7.3 (16.17)	2.2 (8.22)	1.0 (4.46)
Median	0.0	0.0	0.0
Range	0, 100^†	0, 68	0, 35

*All patients were asked if the pain was acceptable, despite the degree of pain experienced and the relative pain to expectation.

^†One patient reported a VAS score of 100 immediately and 1 h after the second dose (Week 4) and immediately after the third dose (Week 8).

VAS Score: 0 (no pain) to 100 (worst possible pain).

AI: autoinjector; APT: all patients treated; SD: standard deviation; VAS: visual analog scale.

Data sharing statement

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