Trial Outcomes & Findings for Open-Label Extension Of Intravenous Mepolizumab In Patients With Hypereosinophilic Syndrome (NCT NCT00097370)

NCT ID: NCT00097370

Last Updated: 2017-07-07

Results Overview

An AE is any untoward medical occurrence in clinical investigation participants temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. AEs are summarized by Treatment phase. Safety and tolerability of the study drug was assessed by number of participants with any AE

• Recruitment status: TERMINATED
• Study phase: PHASE3
• Target enrollment: 78 participants
• Primary outcome timeframe: From the first dose of study medication up to 7 days after the last dose (up to approximately 6 years)
• Results posted on: 2017-07-07

Participant Flow

Participants (par.) who completed 9 months of treatment or withdrew from Study MHE100185 after receiving >=2 infusions of study medication were enrolled in this open label extension study. Par. with daily dose of prednisone >10 milligrams (mg) or <=10 mg at the end of Study MHE100185 were enrolled in Stage 1 or Stage 2 of this study, respectively.

This study was open-label extension to previous Study MHE100185 (NCT00086658). A total of seventy-eight participants participated in this study. Of these, 38 participants previously received placebo in Study MHE100185 and 40 participants previously received mepolizumab in Study MHE100185.

Participant milestones

Measure	Mepolizumab 750 mg Participants received mepolizumab 750 mg by intravenous (IV) infusion monthly in Stage 1 along with concomitant hypereosinophilic syndrome (HES)-active medications that included prednisone (or equivalent) or other HES therapies. In Stage 2, the dosing intervals were optimized for each participant based on the individual's blood eosinophil count and the clinical presentation. In Stage 3, the dosing frequency established in Stage 2 was continued with individual participant monitoring.
Stage 1 STARTED	37
Stage 1 COMPLETED	31
Stage 1 NOT COMPLETED	6
Stage 2 STARTED	72
Stage 2 COMPLETED	59
Stage 2 NOT COMPLETED	13
Stage 3 STARTED	59
Stage 3 COMPLETED	0
Stage 3 NOT COMPLETED	59

Reasons for withdrawal

Measure	Mepolizumab 750 mg Participants received mepolizumab 750 mg by intravenous (IV) infusion monthly in Stage 1 along with concomitant hypereosinophilic syndrome (HES)-active medications that included prednisone (or equivalent) or other HES therapies. In Stage 2, the dosing intervals were optimized for each participant based on the individual's blood eosinophil count and the clinical presentation. In Stage 3, the dosing frequency established in Stage 2 was continued with individual participant monitoring.
Stage 1 Adverse Event	3
Stage 1 Withdrawal by Subject	1
Stage 1 Lack of Efficacy	2
Stage 2 Adverse Event	5
Stage 2 Withdrawal by Subject	1
Stage 2 Lack of Efficacy	3
Stage 2 Pregnancy	1
Stage 2 Sponsor Terminated Study	2
Stage 2 Lost to Follow-up	1
Stage 3 Adverse Event	2
Stage 3 Withdrawal by Subject	3
Stage 3 Lack of Efficacy	1
Stage 3 Sponsor Terminated Study	52
Stage 3 Lost to Follow-up	1

Baseline Characteristics

Open-Label Extension Of Intravenous Mepolizumab In Patients With Hypereosinophilic Syndrome

Baseline characteristics by cohort

Measure	Mepolizumab 750 mg n=78 Participants Participants received mepolizumab 750 mg by IV infusion monthly in Stage 1 along with concomitant HES-active medications that included prednisone (or equivalent) or other HES therapies. In Stage 2, the dosing intervals were optimized for each participant based on the individual's blood eosinophil count and the clinical presentation. In Stage 3, the dosing frequency established in Stage 2 was continued with individual participant monitoring.
Age, Continuous	49.2 Years STANDARD_DEVIATION 14.89 • n=5 Participants
Sex: Female, Male Female	36 Participants n=5 Participants
Sex: Female, Male Male	42 Participants n=5 Participants
Race/Ethnicity, Customized Arabic/North African	2 Participants n=5 Participants
Race/Ethnicity, Customized Black	6 Participants n=5 Participants
Race/Ethnicity, Customized East and South East Asian	2 Participants n=5 Participants
Race/Ethnicity, Customized South Asian	1 Participants n=5 Participants
Race/Ethnicity, Customized White/Caucasian	67 Participants n=5 Participants

PRIMARY outcome

Timeframe: From the first dose of study medication up to 7 days after the last dose (up to approximately 6 years)

Population: Intent-to-Treat (ITT) Population: all enrolled participants who received at least one dose of mepolizumab in this study.

An AE is any untoward medical occurrence in clinical investigation participants temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. AEs are summarized by Treatment phase. Safety and tolerability of the study drug was assessed by number of participants with any AE

Outcome measures

Measure

Mepolizumab 750 mg n=78 Participants Participants received mepolizumab 750 mg by IV infusion monthly in Stage 1 along with concomitant HES-active medications that included prednisone (or equivalent) or other HES therapies. In Stage 2, the dosing intervals were optimized for each participant based on the individual's blood eosinophil count and the clinical presentation. In Stage 3, the dosing frequency established in Stage 2 was continued with individual participant monitoring.

Number of Participants With Any Adverse Event (AE) During the Treatment Phase

76 Participants

PRIMARY outcome

Timeframe: From end of Treatment Phase up to 97 days after the last dose date (up to approximately 6 years)

Population: Follow-up Population: subset of the modified ITT Population who had evidence of being in the study \> length of dosing cycle + 7 days after the date of their last dose of study medication and up to and including 97 days after their last dose date.

An AE is any untoward medical occurrence in clinical investigation participants temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. AEs are summarized by Follow-up phase. Safety and tolerability of the study drug was assessed by number of participants with any AE

Outcome measures

Measure

Mepolizumab 750 mg n=15 Participants Participants received mepolizumab 750 mg by IV infusion monthly in Stage 1 along with concomitant HES-active medications that included prednisone (or equivalent) or other HES therapies. In Stage 2, the dosing intervals were optimized for each participant based on the individual's blood eosinophil count and the clinical presentation. In Stage 3, the dosing frequency established in Stage 2 was continued with individual participant monitoring.

Number of Participants With Any Adverse Event (AE) During the Follow-up Phase

3 Participants

SECONDARY outcome

Timeframe: up to approximately 6 years

Population: ITT Population

Participants who were receiving a prednisone dose level of =<10 mg as their sole background therapy at the end of the study were included for the analysis.

Outcome measures

Measure

Mepolizumab 750 mg n=78 Participants Participants received mepolizumab 750 mg by IV infusion monthly in Stage 1 along with concomitant HES-active medications that included prednisone (or equivalent) or other HES therapies. In Stage 2, the dosing intervals were optimized for each participant based on the individual's blood eosinophil count and the clinical presentation. In Stage 3, the dosing frequency established in Stage 2 was continued with individual participant monitoring.

Number of Participants Achieving a Prednisone Level of =<10 mg (as Sole Background Therapy) at the End of Study

62 Participants

SECONDARY outcome

Timeframe: up to approximately 6 years

Population: ITT Population

The criteria for eosinophil count was achieved if the participant's eosinophil count remained below <600 cell/uL for the last observation on study i.e. within length of dosing cycle + 7 days of last dose of study drug. For participants who entered in Stage 1, HES medications taking prior to the first infusion date in Stage 2 were considered as the lowest background therapy. For participants who entered in Stage 2, HES medications taken on the date that immediately preceded the first infusion date of study drug and had not been discontinued was regarded as the lowest background therapy. If the dose of the lowest background therapy had increased or the medication had changed or the participant had not reached their lowest background therapy, the participant was regarded as not achieving this endpoint.

Outcome measures

Measure

Mepolizumab 750 mg n=78 Participants Participants received mepolizumab 750 mg by IV infusion monthly in Stage 1 along with concomitant HES-active medications that included prednisone (or equivalent) or other HES therapies. In Stage 2, the dosing intervals were optimized for each participant based on the individual's blood eosinophil count and the clinical presentation. In Stage 3, the dosing frequency established in Stage 2 was continued with individual participant monitoring.

Number of Participants Achieving an Eosinophil Level of < 600 Cell/Microliter (uL) (in Addition to the Lowest Background Therapy) at the End of Study

46 Participants

SECONDARY outcome

Timeframe: up to approximately 6 years

Population: ITT Population. Only those participants who completed 9 months of dosing in study MHE100185 and achieved a prednisone level \<=10 mg were analyzed.

Participants from study MHE100185 who completed the 9 months treatment period and achieved a level of <=10 mg of prednisone at study end were analyzed. Duration of doses <=10 mg was determined by examining changes in the prednisone dosing or allowable alternative corticosteroid medication (prednisone equivalents). Start and stop dates of other HES medications were checked to ensure that they did not overlap with the steroid dosing dates. If it did, then the number of days <=10 mg during this overlap was considered as zero and the cumulative days reset to zero, as the endpoint was assessing prednisone dose as sole background therapy. The dosing criteria for this endpoint was considered as achieved if the duration of dosing was minimum of 84 days (3months).

Outcome measures

Measure

Mepolizumab 750 mg n=43 Participants Participants received mepolizumab 750 mg by IV infusion monthly in Stage 1 along with concomitant HES-active medications that included prednisone (or equivalent) or other HES therapies. In Stage 2, the dosing intervals were optimized for each participant based on the individual's blood eosinophil count and the clinical presentation. In Stage 3, the dosing frequency established in Stage 2 was continued with individual participant monitoring.

For Those Participants Who Completed 9 Months of Dosing in Study MHE100185 and Achieved a Prednisone Level <=10 mg: Number of Participants Achieving <= 10 mg Prednisone (as Sole Background Therapy) for >= 3months

39 Participants

SECONDARY outcome

Timeframe: up to approximately 6 years

Population: ITT Population. Only those participants who completed 9 months of dosing in study MHE100185 and achieved a prednisone level \>10 mg were analyzed.

Participants from study MHE100185 who completed the 9 months treatment period and achieved a level of prednisone of >10 mg at the end of the study were analyzed. Duration of doses <= 10 mg were determined by examining changes in the prednisone dosing or allowable alternative corticosteroid medication (prednisone equivalents). Start and stop dates of other HES medications were checked to ensure that they did not overlap with the steroid dosing dates. If overap occurred, then the number of days <=10 mg during this overlap was considered as zero and the cumulative days reset to zero, as the endpoint was assessing prednisone dose as sole background therapy. The dosing criteria for this endpoint was considered as achieved if the duration of dosing was minimum of 53 days (8 weeks).

Outcome measures

Measure

Mepolizumab 750 mg n=6 Participants Participants received mepolizumab 750 mg by IV infusion monthly in Stage 1 along with concomitant HES-active medications that included prednisone (or equivalent) or other HES therapies. In Stage 2, the dosing intervals were optimized for each participant based on the individual's blood eosinophil count and the clinical presentation. In Stage 3, the dosing frequency established in Stage 2 was continued with individual participant monitoring.

For Those Participants Who Completed 9 Months of Dosing in Study MHE100185 and Achieved a Prednisone Level >10 mg: Number of Participants Achieving <=10 mg Prednisone (as Sole Background Therapy) for >= 8 Weeks

5 Participants

SECONDARY outcome

Timeframe: up to approximately 6 years

Population: ITT Population. Only those participants who entered Stage 2 from study MHE100185 with a prednisone level of \<=10 mg prednisone were analyzed.

Participants from study MHE100185 who completed the 9 months treatment period and achieved a level of <=10 mg of prednisone at study end and participants who withdrew from the study early who were at a prednisone dose level <=10 mg were analyzed. Duration of doses <= 10 mg were determined by examining changes in the prednisone dosing or allowable alternative corticosteroid medication (prednisone equivalents). Start and stop dates of other HES medications were checked to ensure that they did not overlap with the steroid dosing dates. If overlap occurred, then the number of days <=10 mg during this overlap was considered as zero and the cumulative days reset to zero, as the endpoint was assessing prednisone dose as sole background therapy. The dosing criteria for this endpoint was considered as achieved if the duration of dosing was minimum of 84 days (3months).

Outcome measures

Measure

Mepolizumab 750 mg n=48 Participants Participants received mepolizumab 750 mg by IV infusion monthly in Stage 1 along with concomitant HES-active medications that included prednisone (or equivalent) or other HES therapies. In Stage 2, the dosing intervals were optimized for each participant based on the individual's blood eosinophil count and the clinical presentation. In Stage 3, the dosing frequency established in Stage 2 was continued with individual participant monitoring.

For Those Participants Who Entered Stage 2 From Study MHE100185 With a Prednisone Level of <=10 mg Prednisone: Number of Participants Achieving a Prednisone Dose <=10 mg (as Sole Background Therapy) for >=3 Months;

43 Participants

SECONDARY outcome

Timeframe: up to approximately 6 years

Population: ITT Population. Only those participants who entered Stage 1 from study MHE100185 with \>10 mg prednisone were analyzed.

Participants from study MHE100185 who completed the 9 months treatment period and achieved a level of >10 mg prednisone at the end of the study and participants who withdrew from the study early who were at a prednisone dose level >10 mg were analyzed. Duration of doses <= 10 mg was determined by examining changes in the prednisone dosing or allowable alternative corticosteroid medication (prednisone equivalents). Start and stop dates of other HES medications were checked to ensure that they do not overlap with the steroid dosing dates. If it did, then the number of days <=10 mg during this overlap was considered as zero and the cumulative days reset to zero, as the endpoint was assessing prednisone dose as sole background therapy. The dosing criteria for this endpoint was considered as achieved if the duration of dosing was minimum of 84 days (3months)

Outcome measures

Measure

Mepolizumab 750 mg n=30 Participants Participants received mepolizumab 750 mg by IV infusion monthly in Stage 1 along with concomitant HES-active medications that included prednisone (or equivalent) or other HES therapies. In Stage 2, the dosing intervals were optimized for each participant based on the individual's blood eosinophil count and the clinical presentation. In Stage 3, the dosing frequency established in Stage 2 was continued with individual participant monitoring.

For Those Participants Who Entered Stage 1 From Study MHE100185 With >10 mg Prednisone: Number of Participants Achieving a Prednisone Dose <=10 mg (as Sole Background Therapy) for>=3 Months

22 Participants

SECONDARY outcome

Timeframe: up to approximately 6 years

Population: ITT Population. Only those participants available at the specified time points were analyzed (represented by n=X in the category titles).

Mean blood eosinophil counts were summarized over time taking into account the effect of HES background therapy. Eosinophil count observations for only those participants taking mepolizumab in conjunction with prednisone or as monotherapy were included.

Outcome measures

Measure	Mepolizumab 750 mg n=78 Participants Participants received mepolizumab 750 mg by IV infusion monthly in Stage 1 along with concomitant HES-active medications that included prednisone (or equivalent) or other HES therapies. In Stage 2, the dosing intervals were optimized for each participant based on the individual's blood eosinophil count and the clinical presentation. In Stage 3, the dosing frequency established in Stage 2 was continued with individual participant monitoring.
Blood Eosinophil Count (With Consideration of the HES Background Therapy) During Stages 1-3 MHE100185 Baseline; n=78	456.2 Cell/uL Standard Deviation 713.81
Blood Eosinophil Count (With Consideration of the HES Background Therapy) During Stages 1-3 MHE100901 Baseline, n=65	467.2 Cell/uL Standard Deviation 719.66
Blood Eosinophil Count (With Consideration of the HES Background Therapy) During Stages 1-3 Week 12; n= 69	176.4 Cell/uL Standard Deviation 228.41
Blood Eosinophil Count (With Consideration of the HES Background Therapy) During Stages 1-3 Week 24; n= 68	272.6 Cell/uL Standard Deviation 499.78
Blood Eosinophil Count (With Consideration of the HES Background Therapy) During Stages 1-3 Week 48; n= 59	163.1 Cell/uL Standard Deviation 146.64
Blood Eosinophil Count (With Consideration of the HES Background Therapy) During Stages 1-3 Week 72; n=49	237.3 Cell/uL Standard Deviation 358.36
Blood Eosinophil Count (With Consideration of the HES Background Therapy) During Stages 1-3 Week 96; n=43	272.8 Cell/uL Standard Deviation 485.06
Blood Eosinophil Count (With Consideration of the HES Background Therapy) During Stages 1-3 Week 120; n=40	174.3 Cell/uL Standard Deviation 172.58
Blood Eosinophil Count (With Consideration of the HES Background Therapy) During Stages 1-3 Week 144; n=36	291.4 Cell/uL Standard Deviation 546.03
Blood Eosinophil Count (With Consideration of the HES Background Therapy) During Stages 1-3 Week 168; n=33	210.6 Cell/uL Standard Deviation 283.35
Blood Eosinophil Count (With Consideration of the HES Background Therapy) During Stages 1-3 Week 192; n=27	208.5 Cell/uL Standard Deviation 249.01
Blood Eosinophil Count (With Consideration of the HES Background Therapy) During Stages 1-3 Week 216; n=23	274.8 Cell/uL Standard Deviation 337.50
Blood Eosinophil Count (With Consideration of the HES Background Therapy) During Stages 1-3 Week 240; n=21	138.1 Cell/uL Standard Deviation 138.08
Blood Eosinophil Count (With Consideration of the HES Background Therapy) During Stages 1-3 Week 264; n=9	466.7 Cell/uL Standard Deviation 533.99
Blood Eosinophil Count (With Consideration of the HES Background Therapy) During Stages 1-3 Week 288; n=2	350.0 Cell/uL Standard Deviation 212.13

SECONDARY outcome

Timeframe: up to approximately 6 years

Population: ITT Population. Only those participants available at end of Stage 2 were included.

The number of participants at the end of Stage 2 with study medication dosing frequencies of 4 weeks, 5-6 weeks, 7-8 weeks, 9-10 weeks, 11-12 weeks, 13-16 weeks, 17-20 weeks, 21-24 weeks and >24 weeks were summarized. The first infusion date in Stage 3 and the last infusion date in Stage 2 were used to calculate the dosing frequency.

Outcome measures

Measure	Mepolizumab 750 mg n=59 Participants Participants received mepolizumab 750 mg by IV infusion monthly in Stage 1 along with concomitant HES-active medications that included prednisone (or equivalent) or other HES therapies. In Stage 2, the dosing intervals were optimized for each participant based on the individual's blood eosinophil count and the clinical presentation. In Stage 3, the dosing frequency established in Stage 2 was continued with individual participant monitoring.
Number of Participants by Dosing Frequency Groups (Defined as Two Week Dosing Ranges Greater Than a 4 Week Interval) at the End of Stage 2 21 to 24 Weeks	4 Participants
Number of Participants by Dosing Frequency Groups (Defined as Two Week Dosing Ranges Greater Than a 4 Week Interval) at the End of Stage 2 <4 Weeks	1 Participants
Number of Participants by Dosing Frequency Groups (Defined as Two Week Dosing Ranges Greater Than a 4 Week Interval) at the End of Stage 2 4 Weeks	5 Participants
Number of Participants by Dosing Frequency Groups (Defined as Two Week Dosing Ranges Greater Than a 4 Week Interval) at the End of Stage 2 5 to 6 Weeks	6 Participants
Number of Participants by Dosing Frequency Groups (Defined as Two Week Dosing Ranges Greater Than a 4 Week Interval) at the End of Stage 2 7 to 8 Weeks	4 Participants
Number of Participants by Dosing Frequency Groups (Defined as Two Week Dosing Ranges Greater Than a 4 Week Interval) at the End of Stage 2 9 to 10 Weeks	5 Participants
Number of Participants by Dosing Frequency Groups (Defined as Two Week Dosing Ranges Greater Than a 4 Week Interval) at the End of Stage 2 11 to 12 Weeks	8 Participants
Number of Participants by Dosing Frequency Groups (Defined as Two Week Dosing Ranges Greater Than a 4 Week Interval) at the End of Stage 2 13 to 16 Weeks	12 Participants
Number of Participants by Dosing Frequency Groups (Defined as Two Week Dosing Ranges Greater Than a 4 Week Interval) at the End of Stage 2 17 to 20 Weeks	8 Participants
Number of Participants by Dosing Frequency Groups (Defined as Two Week Dosing Ranges Greater Than a 4 Week Interval) at the End of Stage 2 >24 Weeks	6 Participants

SECONDARY outcome

Timeframe: Baseline and up to approximately 6 years

Population: ITT Population. Only those participants available at the specified time points were analyzed (represented by n=X in the category titles).

The pruritus visual analogue scale asks participants to rate the status of their Pruritus based on the severity of their itch. Scores range from 0-100 with 0 = No itch and 100 = Worst imaginable itch. Change from Baseline in pVAS score is the difference between the pVAS score at the time point being considered to the MHE100901 Baseline score.

Outcome measures

Measure	Mepolizumab 750 mg n=73 Participants Participants received mepolizumab 750 mg by IV infusion monthly in Stage 1 along with concomitant HES-active medications that included prednisone (or equivalent) or other HES therapies. In Stage 2, the dosing intervals were optimized for each participant based on the individual's blood eosinophil count and the clinical presentation. In Stage 3, the dosing frequency established in Stage 2 was continued with individual participant monitoring.
Change From Baseline in the Pruritus Visual Analogue Scale (pVAS) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 12; n= 58	-6.8 Scores on the scale Standard Deviation 20.01
Change From Baseline in the Pruritus Visual Analogue Scale (pVAS) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 24; n= 51	-4.5 Scores on the scale Standard Deviation 17.49
Change From Baseline in the Pruritus Visual Analogue Scale (pVAS) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 48; n= 46	-5.1 Scores on the scale Standard Deviation 26.19
Change From Baseline in the Pruritus Visual Analogue Scale (pVAS) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 72; n=39	-0.1 Scores on the scale Standard Deviation 20.77
Change From Baseline in the Pruritus Visual Analogue Scale (pVAS) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 96; n=41	1.0 Scores on the scale Standard Deviation 27.63
Change From Baseline in the Pruritus Visual Analogue Scale (pVAS) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 120; n=38	-0.3 Scores on the scale Standard Deviation 17.84
Change From Baseline in the Pruritus Visual Analogue Scale (pVAS) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 144; n=32	-2.8 Scores on the scale Standard Deviation 18.68
Change From Baseline in the Pruritus Visual Analogue Scale (pVAS) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 168; n=33	-4.9 Scores on the scale Standard Deviation 26.55
Change From Baseline in the Pruritus Visual Analogue Scale (pVAS) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 192; n=30	-1.2 Scores on the scale Standard Deviation 21.54
Change From Baseline in the Pruritus Visual Analogue Scale (pVAS) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 216; n=21	-0.8 Scores on the scale Standard Deviation 13.99
Change From Baseline in the Pruritus Visual Analogue Scale (pVAS) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 240; n=17	4.4 Scores on the scale Standard Deviation 12.33
Change From Baseline in the Pruritus Visual Analogue Scale (pVAS) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 264; n=7	2.7 Scores on the scale Standard Deviation 13.14
Change From Baseline in the Pruritus Visual Analogue Scale (pVAS) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 288; n=2	39.5 Scores on the scale Standard Deviation 54.45

SECONDARY outcome

Timeframe: Baseline and up to approximately 6 years

Population: ITT Population. Only those participants available at the specified time points were analyzed (represented by n=X in the category titles).

The erythema subscale score and edema subscale score are each graded on a 0-3 scale, with 0 = absent , 1 = mild, 2 = moderate, 3 = severe. The total score ranged from 0 to 6, with higher scores indicative of more severe Erythema/Edema. The total score was obtained by summing together the responses for each of the two subscale items. Change from Baseline in erythema/edema total score is the difference between erythema/edema total score at the time point being analyzed to the MHE100901 Baseline score..

Outcome measures

Measure	Mepolizumab 750 mg n=78 Participants Participants received mepolizumab 750 mg by IV infusion monthly in Stage 1 along with concomitant HES-active medications that included prednisone (or equivalent) or other HES therapies. In Stage 2, the dosing intervals were optimized for each participant based on the individual's blood eosinophil count and the clinical presentation. In Stage 3, the dosing frequency established in Stage 2 was continued with individual participant monitoring.
Change From Baseline in Erythema/Edema Score 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 12; n= 59	0.0 Scores on a scale Standard Deviation 1.07
Change From Baseline in Erythema/Edema Score 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 24; n= 54	0.0 Scores on a scale Standard Deviation 1.00
Change From Baseline in Erythema/Edema Score 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 48; n= 36	0.0 Scores on a scale Standard Deviation 1.13
Change From Baseline in Erythema/Edema Score 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 72; n=38	0.2 Scores on a scale Standard Deviation 0.98
Change From Baseline in Erythema/Edema Score 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 96; n=21	-0.1 Scores on a scale Standard Deviation 1.01
Change From Baseline in Erythema/Edema Score 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 120; n=11	-0.2 Scores on a scale Standard Deviation 0.60
Change From Baseline in Erythema/Edema Score 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 144; n=9	-0.2 Scores on a scale Standard Deviation 0.67
Change From Baseline in Erythema/Edema Score 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 168; n=6	0.5 Scores on a scale Standard Deviation 1.05
Change From Baseline in Erythema/Edema Score 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 192; n=4	0.8 Scores on a scale Standard Deviation 0.96
Change From Baseline in Erythema/Edema Score 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 216; n=4	0.3 Scores on a scale Standard Deviation 1.26
Change From Baseline in Erythema/Edema Score 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 240; n=11	0.3 Scores on a scale Standard Deviation 0.65
Change From Baseline in Erythema/Edema Score 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 264; n=8	0.0 Scores on a scale Standard Deviation 0.00
Change From Baseline in Erythema/Edema Score 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 288; n=3	-1.0 Scores on a scale Standard Deviation 1.00

SECONDARY outcome

Timeframe: Baseline and up to approximately 6 years

Population: ITT Population. Only those participants available at the specified time points were analyzed (represented by n=X in the category titles).

The SF-12v2 is the 12 item abbreviated form of SF-36v2 survey . It provides information about how participants feel, and how well they have been able to perform their usual activities, over the past 4 weeks. SF-12v2 questions make up 8 scales: Physical Functioning, Role Physical, Bodily Pain, General Health, Vitality, Social Functioning, Role Emotional, Mental Health . Transformed physical component summary score (PCS-12) is derived using all the 12 items and scored onto a 0-100 scale such that a higher score indicates a better health state and better functioning. Change from Baseline in scale or summary measure score is the difference between the score at the time point being analyzed to Baseline.

Outcome measures

Measure	Mepolizumab 750 mg n=75 Participants Participants received mepolizumab 750 mg by IV infusion monthly in Stage 1 along with concomitant HES-active medications that included prednisone (or equivalent) or other HES therapies. In Stage 2, the dosing intervals were optimized for each participant based on the individual's blood eosinophil count and the clinical presentation. In Stage 3, the dosing frequency established in Stage 2 was continued with individual participant monitoring.
Change From Baseline in Quality of Life (QoL) and Current Health Status: Physical Summary Score of the Study Short Form Health Survey (SF-12) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 12; n= 64	-2.0 Scores on the scale Standard Deviation 8.25
Change From Baseline in Quality of Life (QoL) and Current Health Status: Physical Summary Score of the Study Short Form Health Survey (SF-12) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 36; n= 50	-1.4 Scores on the scale Standard Deviation 8.76
Change From Baseline in Quality of Life (QoL) and Current Health Status: Physical Summary Score of the Study Short Form Health Survey (SF-12) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 60; n=48	-1.1 Scores on the scale Standard Deviation 8.91
Change From Baseline in Quality of Life (QoL) and Current Health Status: Physical Summary Score of the Study Short Form Health Survey (SF-12) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 84; n=47	-0.8 Scores on the scale Standard Deviation 8.43
Change From Baseline in Quality of Life (QoL) and Current Health Status: Physical Summary Score of the Study Short Form Health Survey (SF-12) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 108; n=39	-1.0 Scores on the scale Standard Deviation 8.23
Change From Baseline in Quality of Life (QoL) and Current Health Status: Physical Summary Score of the Study Short Form Health Survey (SF-12) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 132; n=37	-1.3 Scores on the scale Standard Deviation 8.33
Change From Baseline in Quality of Life (QoL) and Current Health Status: Physical Summary Score of the Study Short Form Health Survey (SF-12) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 156; n=41	-1.1 Scores on the scale Standard Deviation 8.66
Change From Baseline in Quality of Life (QoL) and Current Health Status: Physical Summary Score of the Study Short Form Health Survey (SF-12) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 180; n=45	-2.1 Scores on the scale Standard Deviation 8.10
Change From Baseline in Quality of Life (QoL) and Current Health Status: Physical Summary Score of the Study Short Form Health Survey (SF-12) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 204; n=43	-2.2 Scores on the scale Standard Deviation 10.02
Change From Baseline in Quality of Life (QoL) and Current Health Status: Physical Summary Score of the Study Short Form Health Survey (SF-12) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 228; n=44	-0.1 Scores on the scale Standard Deviation 9.41
Change From Baseline in Quality of Life (QoL) and Current Health Status: Physical Summary Score of the Study Short Form Health Survey (SF-12) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 252; n=24	-1.3 Scores on the scale Standard Deviation 9.60
Change From Baseline in Quality of Life (QoL) and Current Health Status: Physical Summary Score of the Study Short Form Health Survey (SF-12) 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 276; n=12	-1.4 Scores on the scale Standard Deviation 10.76

SECONDARY outcome

Timeframe: Baseline and up to approximately 6 years

Population: ITT Population. Only those participants available at the specified time points were analyzed (represented by n=X in the category titles).

The SF-12v2 is the 12 item abbreviated form of SF-36v2 survey developed by the Medical Outcomes Trust and QualityMetric Incorporated. It provides information about how participants feel, and how well they have been able to perform their usual activities, over the past 4 weeks. SF-12v2 scale questions make up 8 scales: Physical Functioning, Role Physical, Bodily Pain, General Health, Vitality, Social Functioning, Role Emotional, Mental Health are for mental component summary. Transformed mental component summary score (MCS-12) is derived using all the 12 items and scored onto a 0-100 scale such that a higher score indicates a better health state and better functioning. Change from Baseline in scale or summary measure score is the difference between the score at the time point being analyzed to Baseline.

Outcome measures

Measure	Mepolizumab 750 mg n=75 Participants Participants received mepolizumab 750 mg by IV infusion monthly in Stage 1 along with concomitant HES-active medications that included prednisone (or equivalent) or other HES therapies. In Stage 2, the dosing intervals were optimized for each participant based on the individual's blood eosinophil count and the clinical presentation. In Stage 3, the dosing frequency established in Stage 2 was continued with individual participant monitoring.
Change From Baseline in QoL and Current Health Status: Mental Summary Score of the SF12 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 12; n= 64	2.8 Scores on a scale Standard Deviation 8.46
Change From Baseline in QoL and Current Health Status: Mental Summary Score of the SF12 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 36; n= 50	1.6 Scores on a scale Standard Deviation 10.75
Change From Baseline in QoL and Current Health Status: Mental Summary Score of the SF12 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 60; n=48	2.8 Scores on a scale Standard Deviation 10.34
Change From Baseline in QoL and Current Health Status: Mental Summary Score of the SF12 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 84; n=47	1.5 Scores on a scale Standard Deviation 8.46
Change From Baseline in QoL and Current Health Status: Mental Summary Score of the SF12 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 108; n=39	2.9 Scores on a scale Standard Deviation 11.02
Change From Baseline in QoL and Current Health Status: Mental Summary Score of the SF12 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 132; n=37	5.3 Scores on a scale Standard Deviation 10.20
Change From Baseline in QoL and Current Health Status: Mental Summary Score of the SF12 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 156; n=41	2.1 Scores on a scale Standard Deviation 10.82
Change From Baseline in QoL and Current Health Status: Mental Summary Score of the SF12 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 180; n=45	2.7 Scores on a scale Standard Deviation 11.95
Change From Baseline in QoL and Current Health Status: Mental Summary Score of the SF12 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 204; n=43	1.9 Scores on a scale Standard Deviation 11.54
Change From Baseline in QoL and Current Health Status: Mental Summary Score of the SF12 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 228; n=44	1.8 Scores on a scale Standard Deviation 11.43
Change From Baseline in QoL and Current Health Status: Mental Summary Score of the SF12 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 252; n=24	0.6 Scores on a scale Standard Deviation 12.13
Change From Baseline in QoL and Current Health Status: Mental Summary Score of the SF12 3 Months After the Start of Study MHE100901 and Every 6 Months Thereafter Week 276; n=12	3.3 Scores on a scale Standard Deviation 12.44

Adverse Events

Mepolizumab 750 mg

Serious events: 40 serious events

Other events: 72 other events

Deaths: 0 deaths

Serious adverse events

Measure	Mepolizumab 750 mg n=78 participants at risk Participants received mepolizumab 750 mg by IV infusion monthly in Stage 1 along with concomitant HES-active medications that included prednisone (or equivalent) or other HES therapies. In Stage 2, the dosing intervals were optimized for each participant based on the individual's blood eosinophil count and the clinical presentation. In Stage 3, the dosing frequency established in Stage 2 was continued with individual participant monitoring.
Infections and infestations Pneumonia	5.1% 4/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Acquired immunodeficiency syndrome	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Bronchiectasis	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Bronchitis	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Device related infection	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Gastroenteritis	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Gastroenteritis clostridial	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations HIV infection	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Herpes zoster	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Influenza	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Lobar pneumonia	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Pneumocystis jiroveci pneumonia	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Post procedural infection	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Sepsis	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Upper respiratory tract infection	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
General disorders Pyrexia	3.8% 3/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
General disorders Disease progression	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
General disorders Fatigue	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
General disorders Influenza like illness	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
General disorders Multi-organ failure	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
General disorders Sudden death	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Respiratory, thoracic and mediastinal disorders Dyspnoea	2.6% 2/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Respiratory, thoracic and mediastinal disorders Asthma	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Respiratory, thoracic and mediastinal disorders Nasal polyps	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Respiratory, thoracic and mediastinal disorders Pulmonary fibrosis	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Respiratory, thoracic and mediastinal disorders Respiratory arrest	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Respiratory, thoracic and mediastinal disorders Rhinitis hypertrophic	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Respiratory, thoracic and mediastinal disorders Status asthmaticus	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Gastrointestinal disorders Diarrhoea	2.6% 2/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Gastrointestinal disorders Abdominal pain upper	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Gastrointestinal disorders Gastritis	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Gastrointestinal disorders Gastroenteritis eosinophilic	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Gastrointestinal disorders Gastrooesophageal reflux disease	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Gastrointestinal disorders Pancreatitis	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Nervous system disorders Cervicobrachial syndrome	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Nervous system disorders Haemorrhage intracranial	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Nervous system disorders Ischaemic stroke	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Nervous system disorders Migraine	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Nervous system disorders Motor neurone disease	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Nervous system disorders Myelitis transverse	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Nervous system disorders Optic neuritis	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Nervous system disorders Radiculitis brachial	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Blood and lymphatic system disorders Eosinophilia	2.6% 2/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Blood and lymphatic system disorders Anaemia	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Blood and lymphatic system disorders Autoimmune thrombocytopenia	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Blood and lymphatic system disorders Hypereosinophilic syndrome	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Prostate cancer	2.6% 2/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Angioimmunoblastic T-cell lymphoma	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Hepatic neoplasm	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Multiple myeloma	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Vascular disorders Arterial occlusive disease	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Vascular disorders Extremity necrosis	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Vascular disorders Hypertension	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Vascular disorders Hypotension	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Vascular disorders Temporal arteritis	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Vascular disorders Thrombophlebitis	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Injury, poisoning and procedural complications Accidental overdose	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Injury, poisoning and procedural complications Hip fracture	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Injury, poisoning and procedural complications Splenic rupture	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Thermal burn	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Skin and subcutaneous tissue disorders Eczema	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Skin and subcutaneous tissue disorders Eosinophilic cellulitis	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Skin and subcutaneous tissue disorders Skin erosion	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Swelling face	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Cardiac disorders Cardiac failure	2.6% 2/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Cardiac disorders Atrioventricular block	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Cardiac disorders Bradycardia	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Cardiac disorders Cardiac failure congestive	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Cardiac disorders Myocardial infarction	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Hepatobiliary disorders Cholecystitis acute	2.6% 2/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Hepatobiliary disorders Cholangitis sclerosing	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Metabolism and nutrition disorders Calciphylaxis	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Metabolism and nutrition disorders Dehydration	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Metabolism and nutrition disorders Hypoglycaemia	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Metabolism and nutrition disorders Hypokalaemia	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Renal and urinary disorders Nephrotic syndrome	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Renal and urinary disorders Renal colic	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Renal and urinary disorders Renal failure	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Renal and urinary disorders Renal failure acute	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Investigations Hepatic enzyme increased	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Investigations T-lymphocyte count increased	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Endocrine disorders Adrenal insufficiency	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Musculoskeletal and connective tissue disorders Spinal disorder	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Psychiatric disorders Depression	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Psychiatric disorders Self-injurious ideation	1.3% 1/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study

Other adverse events

Measure	Mepolizumab 750 mg n=78 participants at risk Participants received mepolizumab 750 mg by IV infusion monthly in Stage 1 along with concomitant HES-active medications that included prednisone (or equivalent) or other HES therapies. In Stage 2, the dosing intervals were optimized for each participant based on the individual's blood eosinophil count and the clinical presentation. In Stage 3, the dosing frequency established in Stage 2 was continued with individual participant monitoring.
Respiratory, thoracic and mediastinal disorders Sinusitis	28.2% 22/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Respiratory, thoracic and mediastinal disorders Upper respiratory tract infection	28.2% 22/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Respiratory, thoracic and mediastinal disorders Bronchitis	26.9% 21/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Respiratory, thoracic and mediastinal disorders Nasopharyngitis	23.1% 18/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Rhinitis	11.5% 9/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Ear infection	9.0% 7/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Gastroenteritis	7.7% 6/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Pharyngitis	7.7% 6/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Urinary tract infection	7.7% 6/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Cystitis	6.4% 5/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Gastroenteritis viral	6.4% 5/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Herpes zoster	6.4% 5/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Localised infection	6.4% 5/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Respiratory tract infection	6.4% 5/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Fungal infection	5.1% 4/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Influenza	5.1% 4/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Infections and infestations Pneumonia	5.1% 4/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
General disorders Fatigue	29.5% 23/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
General disorders Pyrexia	17.9% 14/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
General disorders Influenza like illness	12.8% 10/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
General disorders Pain	12.8% 10/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
General disorders Oedema peripheral	11.5% 9/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
General disorders Chest pain	10.3% 8/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
General disorders Oedema	9.0% 7/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
General disorders Asthenia	6.4% 5/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
General disorders Local swelling	5.1% 4/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Gastrointestinal disorders Nausea	23.1% 18/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Gastrointestinal disorders Abdominal pain	21.8% 17/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Gastrointestinal disorders Diarrhoea	21.8% 17/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Gastrointestinal disorders Vomiting	12.8% 10/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Gastrointestinal disorders Abdominal pain upper	10.3% 8/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Gastrointestinal disorders Dyspepsia	10.3% 8/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Gastrointestinal disorders Abdominal discomfort	9.0% 7/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Gastrointestinal disorders Gastrooesophageal reflux disease	7.7% 6/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Gastrointestinal disorders Constipation	5.1% 4/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Gastrointestinal disorders Gastritis	5.1% 4/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Gastrointestinal disorders Oesophagitis	5.1% 4/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Gastrointestinal disorders Toothache	5.1% 4/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Respiratory, thoracic and mediastinal disorders Cough	33.3% 26/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Respiratory, thoracic and mediastinal disorders Dyspnoea	21.8% 17/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Respiratory, thoracic and mediastinal disorders Asthma	14.1% 11/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Respiratory, thoracic and mediastinal disorders Oropharyngeal pain	14.1% 11/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Respiratory, thoracic and mediastinal disorders Epistaxis	7.7% 6/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Respiratory, thoracic and mediastinal disorders Rhinorrhoea	7.7% 6/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Respiratory, thoracic and mediastinal disorders Nasal congestion	6.4% 5/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Respiratory, thoracic and mediastinal disorders Sinus congestion	6.4% 5/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Respiratory, thoracic and mediastinal disorders Wheezing	5.1% 4/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Musculoskeletal and connective tissue disorders Arthralgia	24.4% 19/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Musculoskeletal and connective tissue disorders Back pain	20.5% 16/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Musculoskeletal and connective tissue disorders Pain in extremity	16.7% 13/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Musculoskeletal and connective tissue disorders Myalgia	14.1% 11/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Musculoskeletal and connective tissue disorders Muscle spasms	11.5% 9/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Musculoskeletal and connective tissue disorders Neck pain	6.4% 5/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Skin and subcutaneous tissue disorders Rash	21.8% 17/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Skin and subcutaneous tissue disorders Pruritus	19.2% 15/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Skin and subcutaneous tissue disorders Urticaria	16.7% 13/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Skin and subcutaneous tissue disorders Erythema	7.7% 6/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Skin and subcutaneous tissue disorders Night sweats	6.4% 5/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Nervous system disorders Headache	29.5% 23/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Nervous system disorders Hypoaesthesia	15.4% 12/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Nervous system disorders Dizziness	11.5% 9/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Nervous system disorders Paraesthesia	7.7% 6/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Blood and lymphatic system disorders Hypereosinophilic syndrome	9.0% 7/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Blood and lymphatic system disorders Anaemia	7.7% 6/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Blood and lymphatic system disorders Thrombocytopenia	6.4% 5/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Psychiatric disorders Anxiety	11.5% 9/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Psychiatric disorders Insomnia	7.7% 6/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Psychiatric disorders Depression	6.4% 5/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Investigations Weight decreased	9.0% 7/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Metabolism and nutrition disorders Decreased appetite	9.0% 7/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Injury, poisoning and procedural complications Contusion	7.7% 6/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Cardiac disorders Palpitations	6.4% 5/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Eye disorders Vision blurred	5.1% 4/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study
Vascular disorders Hypotension	5.1% 4/78 • On treatment serious adverse events (SAEs) and non-serious adverse events (AEs) were collected from from the first dose of study medication up to 7 days after the last dose (up to approximately 6 years). SAEs and non-serious AEs were collected in members of the Intent to treat (ITT)population, comprised of all enrolled participants who received at least one dose of mepolizumab in this study

Additional Information

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Results disclosure agreements

• Principal investigator is a sponsor employee GSK agreements may vary with individual investigators, but will not prohibit any investigator from publishing. GSK supports the publication of results from all centers of a multi-center trial but requests that reports based on single-site data not precede the primary publication of the entire clinical trial.
• Publication restrictions are in place

Restriction type: OTHER