Mepolizumab

A HES flare is defined as a HES related clinical manifestation based on a physician-documented change in clinical signs or symptoms (worsening symptoms and/or elevated blood eosinophil level) which resulted in need for either: an increase from the most recent dose in the maintenance Oral Corticosteroid (OCS) dose (prednisone/prednisolone equivalent) by at least 10 mg per day for 5 days or an increase in or addition of any immunosuppressive and/or cytotoxic HES therapy from/to the most recent dose of HES therapy. Data is presented by the number of HES flares (0, 1, 2, 3 ,4 and \>=5) in the participants.

Total endoscopic nasal polyp score is collected at clinical visits. Independent reviewers, blinded to treatment, reviewed image recordings of nasal endoscopies to determine total endoscopic NP score based on NP size. The right and left nostrils were scored from 0 to 4 (0 = No polyps; 1 = Small polyps in the middle meatus not reaching below the inferior border of the middle concha; 2 = Polyps reaching below the lower border of the middle turbinate; 3 = Large polyps reaching the lower border of the inferior turbinate or polyps medial to the middle concha; and 4 = Large polyps causing complete obstruction/congestion of the inferior meatus). The total score is the sum of the right and left nostril scores and ranges from 0 to 8 (calculated by summing the scores \[0 to 4\] in each nostril), higher scores indicate worse status. Baseline was defined as Day 1 value. Change from Baseline = Post-baseline value minus Baseline value.

Total endoscopic nasal polyp score is collected at clinical visits. The assessments were performed by central video image recordings of nasal endoscopy (NE). The right and left nostrils were scored from 0 to 4 (0 = No polyps; 1 = Small polyps in the middle meatus not reaching below the inferior border of the middle concha; 2 = Polyps reaching below the lower border of the middle turbinate; 3 = Large polyps reaching the lower border of the inferior turbinate or polyps medial to the middle concha; and 4 = Large polyps causing complete obstruction/congestion of the inferior meatus). The total score is the sum of the right and left nostril scores and ranges from 0 to 8 (calculated by summing the scores \[0 to 4\] in each nostril), "0" score represents better status while "8" represents worse status. Baseline was defined as last value prior to first dose (Day 1). Change from Baseline = Post-baseline value minus Baseline value.

Participants rated individual (nasal obstruction, nasal discharge, mucus in the throat, loss of smell, facial pain) and overall symptoms on a visual analog scale (VAS) using an electronic diary (eDiary). Captured scores ranged between 0 (none) and 100 (as bad as you can imagine), final scores derived from the electronically captured scores by dividing by 10. The final nasal obstruction VAS score ranged between 0 (none) and 10 (worst), with higher scores indicating greater disease severity. The average of daily scores in 4-weekly intervals were calculated and data is presented for Weeks 49-52. Baseline was defined as the average score from the 7 days of eDiary data collected prior to Day 1. Change from Baseline = Post-baseline value minus Baseline value.

Participants rated individual (nasal obstruction, nasal discharge, mucus in the throat, loss of smell, facial pain) and overall symptoms on a visual analog scale (VAS) using an electronic diary (eDiary). Captured scores ranged between 0 (none) and 100 (as bad as you can imagine), final scores derived from the electronically captured scores dividing by 10. The final nasal obstruction VAS score ranged between 0 and 10, with higher scores indicating greater disease severity. The average of daily scores in 4-weekly intervals were calculated and data is presented for Weeks 49-52. Baseline was defined as the average score from the 7 days of eDiary data collected prior to Day 1. Change from Baseline = Post-baseline value minus Baseline value.

Annualized rate of moderate or severe exacerbations were assessed. Moderate exacerbations are defined as clinically significant exacerbations that require treatment with oral or systemic corticosteroids and/or antibiotics. Severe exacerbations are defined per protocol as clinically significant exacerbations that require in-patient hospitalization (that is greater than or equal to \[\>=\] 24 hours) or result in death.

An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of a study treatment, whether or not considered related to the study treatment. Serious AE was defined as any untoward medical occurrence that, at any dose results in death, is life-threatening, requires hospitalization or prolongation of existing hospitalization, results in persistent disability/incapacity, congenital anomaly/birth defect or any other situation according to medical or scientific judgment. Non-serious AEs from start of study treatment until 28 days after last dose (up to Week 20) are reported. Number of participants with common (\>=3% incidence) non-serious AEs are presented.

An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of a study treatment, whether or not considered related to the study treatment. Serious AE was defined as any untoward medical occurrence that, at any dose results in death, is life-threatening, requires hospitalization or prolongation of existing hospitalization, results in persistent disability/incapacity, congenital anomaly/birth defect or any other situation according to medical or scientific judgment. Number of participants with serious AEs are presented.

Blood samples were analyzed for the presence of anti-mepolizumab antibodies by binding anti-drug antibody (ADA) assay. The binding ADA assay results at each visit were summarized as negative or positive. The binding ADA assay was performed in three steps; screening, confirmation and titration. The screening assay produced a result of positive or negative relative to a screening cut point. Positive samples continued with the confirmation assay, which also produced a result of positive or negative relative to a confirmation cut point. For positive confirmation samples, a titre value was obtained to quantify the degree of binding in a titration assay. Participants were considered 'Positive' if they had a positive confirmation ADA assay result.

Independent reviewers, blinded to treatment, reviewed image recordings of nasal endoscopies to determine total endoscopic NP score based on NP size. The right and left nostrils were scored from 0 to 4 (0 = No polyps; 1 = Small polyps in the middle meatus not reaching below the inferior border of the middle concha; 2 = Polyps reaching below the lower border of the middle turbinate; 3 = Large polyps reaching the lower border of the inferior turbinate or polyps medial to the middle concha; and 4 = Large polyps causing complete obstruction/congestion of the inferior meatus). The total score is the sum of the right and left nostril scores and ranges from 0 to 8, higher scores indicate greater disease severity. Data up to Week 52, including from participants who remained in the study after early discontinuation from IP, were included in analysis. Baseline was defined as Day 1 value. Change from Baseline = Post-baseline value minus Baseline value.

Participants rated individual (nasal obstruction, nasal discharge, mucus in the throat, loss of smell, facial pain) and overall symptoms on a visual analog scale (VAS) using an electronic diary (eDiary). Captured scores ranged between 0 (none) and 100 (as bad as you can imagine), final scores derived from the electronically captured scores by dividing by 10. The final nasal obstruction VAS score ranged between 0 and 10, with higher scores indicating greater disease severity. Data up to Week 52, including from participants who remained in the study after early discontinuation from IP, were included in analysis. The average of daily scores in 4-weekly intervals were calculated and data is presented for Weeks 49-52. Baseline was defined as the average score from the 7 days of eDiary data collected prior to Day 1. Change from Baseline = Post-baseline value minus Baseline value.

Due to differences in the labelling requirements among regulatory authorities around the world, two different labelling approaches were included in this global study: labelling that includes a pictogram plus standard labelling elements, or a standard labelling without the pictogram. Participants (and/or their caregiver) attended three on treatment visits at Week 0, 4, 8, and End of Study Visit. Training on the study treatment, device handling and administration technique was provided by the investigator or qualified site staff at Week 0 and then first dose was self-administered under observation of investigator/site staff in clinic. Second dose self-administered unobserved, at home (Week 4) and third dose was self-administered under the observation of investigator/site staff in clinic (Week 8). All Subjects (Safety) Population included all enrolled participants attempting at least one self-administration of mepolizumab. Only participants with data available at Week 8 were analyzed.

Due to differences in the labeling requirements among regulatory authorities around the world, two different labeling approaches were included in this global study: labeling that includes a pictogram plus standard labeling elements, or a standard labeling without the pictogram. Participants (and/or their caregiver) attended three on treatment visits at Week 0, Week 4, Week 8, and the End of Study Visit. Training on the study treatment, device handling and administration techniques was provided by the investigator or qualified site staff at Week 0 and then first dose was self-administered under observation of investigator/site staff in clinic. Second dose self-administered unobserved, at home (Week 4) and third dose was self-administered under the observation of investigator/site staff in clinic (Week 8). Only participants with data available at Week 8 were analyzed.

Percentage of participants who experienced \>=1 HES flare during the 32-Week treatment period or who withdrew from the study has been presented. A HES flare is defined as a HES related clinical manifestation based on a physician-documented change in clinical signs or symptoms which resulted in need for an increase in the maintenance Oral Corticosteroid (OCS) dose by at least 10 mg per day for 5 days or an increase in or addition of any cytotoxic or immunosuppressive HES therapy. HES flare is also defined as receipt of two or more courses of blinded active OCS during the treatment period. Intent-to-treat (ITT) Population comprises of all randomized participants. This population was based on the treatment to which the participants were randomized. Any participant who received a treatment randomization number were considered to be randomized.

During the clinic visits the Investigator or designee evaluated if the participants were able to self-administer the third dose at Week 8 by visual inspection immediately following injection and by using an 'Observer checklist' based on the safety syringe Instructions for Use (IFU). The 'self-administration' was defined as administration of mepolizumab liquid drug product in safety syringe either by the participants themselves or by their caregiver. Failure to perform one of the critical steps was deemed to be failure to successfully administer the injection. Participants with data available at Week 8 have been analyzed. Analysis was performed on All Subjects (Safety) Population which comprised of all enrolled participants attempting at least one self administration of mepolizumab liquid drug product in a safety syringe.

Blood samples were collected at indicated time points. Cmax following a single dose administration of liquid mepolizumab using a safety syringe and an autoinjector were compared with reconstituted lyophilized drug product from the vial. Pharmacokinetic (PK) Population comprised of all participants receiving study drug for whom a pharmacokinetic sample was obtained and analyzed.

Blood samples were collected at indicated time points. AUC(0-t) and AUC(0-inf) following a single dose administration of liquid mepolizumab using a safety syringe and an autoinjector were compared with lyophilized drug product. Fixed effects analysis of covariance model was used for analysis. Only those participants with data available at the specified data points were analyzed (represented by n=X in category titles).

Clinically significant exacerbation was defined as worsening of asthma which requires use of systemic corticosteroids (e.g., prednisone) for at least 3 days or a single intramuscular (IM) corticosteroid dose and/or hospitalization and/or emergency department (ED) visits. For participants on maintenance systemic corticosteroids, at least double the existing maintenance dose for at least 3 days is required. Percentage of participants with clinically significant exacerbation over time during the on-treatment period of Part C and 95% confidence interval were estimated using Kaplan-Meier estimates. Intent-to-Treat Population includes all randomized participants who received at least one dose of double-blind study medication within Part C.

An AE is any untoward medical occurrence in a subject, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. SAE is defined as any untoward medical occurrence that, at any dose: results in death; is life-threatening; requires hospitalization or prolongation of existing hospitalization; results in disability/incapacity; is a congenital anomaly/birth defect; other important medical events based on medical or scientific judgment; and is associated with liver injury and impaired liver function. Additionally, systemic (that is, allergic/hypersensitivity and non-allergic) reactions and local injection site reactions were recorded throughout the treatment and follow-up period.

SGRQ consisted of 50 questions (scored from 0 to 100 where 0 indicates best and 100 indicates worst health) designed to measure Quality of Life in par. with diseases of airway obstruction, measuring symptoms, impact, and activity. Questions were completed by the par. with a recall over the past 4 weeks. SGRQ Total Score was calculated by summing the pre-assigned weights of answers, dividing by the sum of the maximum weights for items in SGRQ and multiplying by 100 to get a %. Change from BL in SGRQ was calculated as value at Week 24 minus value at BL for each par. and was analyzed using mixed model repeated measures allowing for covariates of BL value, region, BL maintenance oral corticosteroid (OCS) therapy, exacerbations in the year prior to the study (as an ordinal variable), BL % predicted FEV1 and visit, plus interaction terms for visit by BL and visit by treatment group. Modified Intent-to-Treat (mITT) Population consisted of all randomized par. who received \>= 1 dose of drug.

Exacerbations are defined as the worsening of asthma which requires use of systemic corticosteroids intravenous (IV) or oral steroid like prednisone, for at least 3 days or a single intramuscular (IM) corticosteroid (CS) dose is required. For maintenance systemic corticosteroids, at least double the existing maintenance dose for at least 3 days was required) and/or hospitalization and/or emergency department (ED) visit. On-Treatment data between first dose date and earliest of Withdrawal date/last dose + 28 days was considered for analysis. Analysis of the number of exacerbations was performed using a negative binomial generalized linear model.

An AE is any untoward medical occurrence in a participant or clinical investigation participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. Any untoward event resulting in death, life threatening, requires hospitalization or prolongation of existing hospitalization, results in disability/incapacity, congenital anomaly/birth defect, any other situation according to medical or scientific judgment that may not be immediately life-threatening or result in death or hospitalization but may jeopardize the participant or may require medical or surgical intervention or event associated with liver injury and impaired liver function were categorized as SAE. On-treatment AEs and on-treatment SAEs are the events occurring on/after the first dose of open-label mepolizumab date and before/on last dose+28 days.

Moderate exacerbations are defined as clinically significant exacerbations that require treatment with oral/systemic corticosteroids and/or antibiotics. Severe exacerbations are defined as clinically significant exacerbations that require in-patient hospitalization (\>=24 hours) or result in death. Moderate and severe exacerbations occurring from the start of investigational product (IP) up to the Week 52 visit, including exacerbations reported after early discontinuation from IP by participants who remained in the study, were included in the analysis. The analysis was performed on the modified intent-to-treat (mITT) Population (all randomized participants who received at least one dose of study treatment).

Moderate exacerbations are defined as clinically significant exacerbations that require treatment with oral/systemic corticosteroids and/or antibiotics. Severe exacerbations are defined as clinically significant exacerbations that require in-patient hospitalization ( \>= 24 hours) or result in death. Moderate and severe exacerbations occurring from the start of investigational product (IP) up to the Week 52 visit, including exacerbations reported after early discontinuation from investigational product by subjects who remained in the study, were included in the analysis. The analysis was performed on the mITT high stratum (mITT-H) Population which comprised of participants in the mITT Population (all randomized participants who received at least one dose of study treatment) with blood eosinophil counts \>=150 cells/µL at Screening or \>=300 cells/ µL in the 12 months prior.

Moderate and severe exacerbations occurring from the start of IP up to the Week 52 visit, including exacerbations reported after early discontinuation from IP by participants who remained in the study, were included in the analysis. The analysis was performed on the mITT Population which comprised of all randomized participants who received at least one dose of trial medication. The strata were combined as pre-specified in the protocol and reporting and analysis plan (RAP).

Total accrued duration of remission is the accrued number of weeks where Birmingham Vasculitis Activity Score (BVAS) =0 plus prednisolone/prednisone dose \<=4 mg/day over the 52 week study treatment period was reported. The accrued duration was categorized into zero, \>0 to \<12 weeks, 12 to \<24 weeks, 24 to \<36 weeks and \>=36 weeks. Statistical analysis was based on a proportional odds regression model with covariates including treatment group, Baseline prednisolone/prednisone daily dose, Baseline BVAS score and region. Intent-to-Treat (ITT) Population was used for the analysis and was defined as all participants who were randomized and received at least one dose of trial medication. Randomized participants were assumed to have received study treatment unless definitive evidence to the contrary exists. The odds ratio for treatment difference and associated probability (p)-value and 95 percent confidence interval (CI) were calculated.

The number of participants who were in remission (i.e ., BVAS=0 and prednisolone /prednisone \<=4 mg/day) at both Weeks 36 and 48 of the study treatment period was reported. The statistical analysis was performed using a logistic regression model on ITT Population. The odds ratio for treatment difference and associated p-value and 95 percent CI were calculated.

AEs were collected from the Baseline visit until the follow-up visit (approx. 12 weeks post-last dose). Participants were monitored to evaluate the AEs of systemic and local site reaction. AE is defined as any untoward medical occurrence in a patient or clinical investigation subject, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. On treatment AEs were defined as events occurring from the first dose until 28 days after the last dose of mepolizumab.

Clinically significant exacerbations of asthma are defined as worsening of asthma which required use of systemic corticosteroids (IV or oral steroid like prednisone, for at least 3 days or a single intramuscular (IM) corticosteroid (CS) dose is required. For maintenance of systemic corticosteroids, at least double the existing maintenance dose for at least 3 days was required) and/or hospitalization and/or emergency department (ED) visits. The frequency of clinically significant exacerbations of asthma over the 32-week treatment period is expressed as the number of exacerbations per year. Analysis of the number of exacerbations performed using a negative binomial model with covariates of treatment group, baseline maintenance OCS therapy (OCS vs. no OCS), region, exacerbations in the year prior to the study (as an ordinal variable) and baseline % predicted FEV1, and with logarithm of time on treatment as an offset variable.

Baseline (BL) dose was the prescribed optimized prednisone/prednisolone dose following the OCS Optimization Phase. Maintenance (MN) dose was the mean of all daily prednisone/prednisolone doses during the MN Phase (weeks 20 to 24). The percent reduction of OCS dose during weeks 20 to 24 compared to BL dose was calculated as: 100 x (BL dose minus MN dose)/BL dose. Asthma control between weeks 20 and 24 was defined as no clinically significant exacerbation (worsening of asthma that required use of systemic corticosteroids or hospitalization and/or emergency department visits) during this period. The percent reduction of OCS was categorized as: 90 to 100%; 75 to \<90%; 50 to \<75%; \>0 to \<50%; no decrease in prednisone dose, or lack of asthma control, or withdrawal (WD) from treatment. Analysis was performed using a proportional odds model with terms for treatment group, region, duration of OCS use at BL (\<5 years vs. \>=5 years) and BL OCS dose.

AE is any untoward medical occurrence in a participant or clinical investigation participant, temporally associated with use of a medicinal product (MP), whether or not considered related to MP. AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with use of MP. SAE is any untoward medical occurrence that, at any dose results in death, is life-threatening, requires hospitalization or prolongation of existing hospitalization, results in disability/incapacity, or is a congenital anomaly/birth defect or is medically significant or all events of possible drug induced liver injury with hyperbilirubinemia. As Treated (AT) Population consisted of participants who received at least one dose of open label mepolizumab. On-treatment AEs and on-treatment SAEs are the events occurring on/after the first dose of open-label mepolizumab date and before/on last dose of mepolizumab + 28 days.

Dysphagia will be assessed by the Eosinophilic Esophagitis Symptom Activity Index (EEsAI) which measures dysphagia frequency, dysphagia severity, and food avoidance/modification behaviors. EEsAI scores range from 0 to 100, with higher scores indicating more severe symptoms. A decrease of ≥ 20 points is felt to be a meaningful clinical response and scores ≤ 20 representing clinical remission.

PK of mepolizumab was evaluated in participants using Cmax. PK samples were collected at pre-dose on Weeks 4 and 8; and at Weeks 9, 12, 16 and 20 post-dose. Cmax was evaluated by population PK methods and mean and standard error from the final model has been tabulated. Estimates have been presented from the final model centered to mean bodyweights of 27 kg, 50 kg and 70 kg. Note the average bodyweight of 70 kg (mean body weight observed in adults) was not investigated in the study. PK Population included all participants receiving at least one dose of mepolizumab beginning at Visit 2 (Week 0) and having at least one blood sample taken at Visit 3 (Week 4) or thereafter with measurable mepolizumab plasma concentration.

PK of mepolizumab was evaluated in participants using AUC (0-inf). PK samples were collected at pre-dose on Weeks 4 and 8; and at Weeks 9, 12, 16 and 20 post-dose. AUC (0-inf) was evaluated by population PK methods and mean and standard error from the final model has been tabulated. Estimates have been presented from the final model centered to mean bodyweights of 27 kg, 50 kg and 70 kg. Note the average bodyweight of 70kg (mean body weight observed in adults) was not investigated in the study.

PK of mepolizumab was evaluated in participants using t1/2. PK samples were collected at pre-dose on Weeks 4 and 8; and at Weeks 9, 12, 16 and 20 post-dose. T1/2 was evaluated by population PK methods and mean and standard error from the final model has been tabulated. Estimates have been presented from the final model centered to mean bodyweights of 27 kg, 50 kg and 70 kg. Note the average bodyweight of 70kg (mean body weight observed in adults) was not investigated in the study.

PK of mepolizumab was evaluated in participants using CL/F. PK samples were collected at pre-dose on Weeks 4 and 8; and at Weeks 9, 12, 16 and 20 post-dose. CL was evaluated by population PK methods and mean and standard error from the final model has been tabulated. Estimates have been presented from the final model centered to mean bodyweights of 27 kg, 50 kg and 70 kg. Note the average bodyweight of 70kg (mean body weight observed in adults) was not investigated in the study.

PD of mepolizumab was evaluated in participants using ratio to Baseline in absolute blood eosinophil count. Blood samples were collected at indicated time points. Baseline was defined as the latest value recorded prior to the first dose of mepolizumab. Ratio to Baseline was calculated as post-dose visit value/Baseline value. It was evaluated by Pharmacodynamic Eosinophils (PDe) Population which included all participants receiving at least one dose of mepolizumab beginning at Visit 2 (Week 0) and having at least one Part A blood sample evaluable for blood eosinophil count.

An AE is any untoward medical occurrence in a participant or clinical investigation participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. Any untoward event resulting in death, life threatening, requires hospitalization or prolongation of existing hospitalization, results in disability/incapacity, congenital anomaly/birth defect, any other situation according to medical or scientific judgment or all events of possible drug-induced liver injury with hyperbilirubinemia are to be categorized as SAE. On-treatment SAEs and non-SAEs are defined as events occurring from the first Part B dose until 28 days following the last Part B dose. Safety Population includes all participants who received at least one dose of mepolizumab beginning at Visit 9.

Blood sample were collected for the determination of anti-mepolizumab binding antibodies and neutralizing antibodies response in Part B at Weeks 44, 68 and 80 prior to study treatment administration. Participant was considered 'Positive' if they had at least one positive post-Baseline anti-drug antibody assay result. All Part B visits (including scheduled and unscheduled) post-Baseline were considered for Any-time Post-Baseline visit derivation. The number of participants with positive anti-mepolizumab binding antibodies and neutralizing antibodies response at Any Time Post Baseline has been presented. The neutralizing antibodies response results only presented for participants with positive anti-drug antibody assay.

Sitting blood pressure measurements included SBP and DBP. Measurements were done pre-infusion/injection with the participant sitting, having rested in this position for at least 5 minutes before each reading. The Baseline was defined as the latest value recorded prior to the first dose of mepolizumab. Change from Baseline was defined as value at indicated time point minus Baseline value. Only those participants with data available at the specified time points were analyzed (represented by n=X in the category titles).

Sitting pulse rate measurements were performed pre-infusion/injection with the participant sitting, having rested in this position for at least 5 minutes before each reading. The Baseline was defined as the latest value recorded prior to the first dose of mepolizumab in Part A. Change from Baseline was defined as value at indicated time point minus Baseline value. Only those participants with data available at the specified time points were analyzed (represented by n=X in the category titles).

Blood samples were collected for analysis of alanine aminotransferase (ALT), alkaline phosphatase (ALP), aspartate aminotransferase (AST), gamma glutamyl transferase (GGT), albumin, protein, bilirubin, creatinine, urate, direct bilirubin, calcium, carbon dioxide (CO2), chloride, glucose, potassium, sodium and urea. Baseline was defined as the latest value recorded prior to the first dose of mepolizumab in Part A. Change from Baseline was defined as value at indicated time point minus Baseline value. All Part B visits (scheduled and unscheduled) post-Baseline were considered for Any-time Post-Baseline visit derivation. If participant had at least one value for categories "To Low" and/or "To High" along with "To Normal or No Change" then participant was counted under "To Low" and/or "To High". If participant had values which belong only to "To Normal or No Change" then participant was counted under "To Normal or No Change" only. Any Time Post-Baseline values have been presented.

Blood samples were collected for analysis of basophils, eosinophils, leukocyte, monocyte, neutrophils, lymphocyte, platelets, mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), hemoglobin (Hgb), mean corpuscular volume (MCV), erythrocytes, hematocrit, and reticulocytes/erythrocytes (Ret/Ery). Baseline was defined as the latest value recorded prior to first dose of mepolizumab in Part A. Change from Baseline was defined as value at indicated time point minus Baseline value. All Part B visits (scheduled and unscheduled) post-Baseline were considered for Any-time Post-Baseline visit derivation. If participant had at least one value for categories "To Low" and/or "To High" along with "To Normal or No Change" then participant was counted under "To Low" and/or "To High". If participant had values which belong only to "To Normal or No Change" then participant was counted under "To Normal or No Change" only. Any Time Post-Baseline values have been presented.

Urine samples were collected from participants at indicated time points for analysis of urinalysis parameters including Specific gravity and potential of hydrogen (pH) of urine, presence of glucose, protein, blood and ketones in urine by dipstick test. Microscopic examination was performed if blood or protein was abnormal. Only those participants with data available at the specified time points were analyzed.

Change from Baseline in blood eosinophils was calculated as the post-Baseline value minus the Baseline value. The change from Baseline in log-transformed blood eosinophil levels at Week 12 was analyzed using both a linear and non-linear (Imax) dose response models. The dose response was found to be non-linear and hence only the results of the non-linear model are presented. Mepolizumab 75mg IV assumed to equate to 100 mg SC within model. Prior to log10-transformation, zero values were imputed with half the minimum value across all dose groups and time points. An adjustment for Baseline eosinophil count was also incorporated into the model.

Area under the absolute blood eosinophil time curve to Day 84 (AUECeos\[0-day 84\]) determined using the linear trapezoidal rule for subset of participants with blood eosinophil data to Day 84. Blood samples for the analyses of AUEC(eos) (0-day 84) were collected at Days 1, 3, 7, 28, 56, 70 and 84.

Blood samples were collected at Days 1, 3, 7, 28, 56, 70, 84, 112 and 140 to assess the maximum reduction from Baseline in blood eosinophils between Day 1 pre-dose and last quantifiable study measurement. Change from Baseline was calculated as the ratio of the post-Baseline value divided by the Baseline value. The maximum reduction from Baseline in eosinophils is represented by the minimum ratio to Baseline.

Blood samples were collected at Days 1, 3, 7, 28, 56, 70, 84, 112 and 140 to assess the time to first occurrence of maximum reduction from baseline in blood eosinophil levels between Day 1 pre-dose and last quantifiable study measurement.

This summarizes the number of participants who returned to at least 50% of their Baseline blood eosinophil levels after maximum inhibition had been achieved and without any subsequent decrease in blood eosinophil levels. Blood samples were collected at Days 1, 3, 7, 28, 56, 70, 84, 112 and 140.

AUC of mepolizumab was estimated by population modeling techniques using non-linear mixed effect methods for the individual and population pharmacokinetic parameters from the sparse sampling. Individual cumulative plasma of mepolizumab AUC to Day 84 (cumAUC(0-day 84)), is the sum of the AUCs over each dosing interval after each of the three doses administered, for those participants with data up to Day 84. Individual cumulative plasma of mepolizumab AUC to Day 140 (cumAUC(0-day 140) is the sum of the AUCs over each dosing interval after each of the three doses administered plus the AUC post the last dose interval up to Day 140 (i.e. from Day 84 to Day 140). Blood samples for PK analyses were collected on dosing days (Days 1, 28 and 56) at pre-dose and 0.5 hour (h), 1 h and 2 h post-dose (time was relative to the end of infusion in the IV cohort) as well as on Days 3, 7, 70, 84, 112 and 140 (follow-up visit).

Maximum plasma concentration was estimated by population modelling techniques using non-linear mixed effect methods for the individual and population pharmacokinetic parameters from the sparse sampling. Blood samples for PK analyses of mepolizumab were collected on dosing days (Days 1, 28 and 56) at pre-dose and 0.5 h, 1 h and 2 h post-dose (time was relative to the end of infusion in the IV cohort) as well as on Days 3, 7, 70, 84, 112 and 140 (follow-up visit).

Time to maximum plasma concentration was estimated by population modelling techniques using non-linear mixed effect methods for the individual and population pharmacokinetic parameters from the sparse sampling. Blood samples for PK analyses of mepolizumab were collected on dosing days (Days 1, 28 and 56) at pre-dose and 0.5 h, 1 h and 2 h post-dose (time was relative to the end of infusion in the IV cohort) as well as on Days 3, 7, 70, 84, 112 and 140 (follow-up visit).

Terminal half-life (t1/2) was estimated by modelling techniques using non-linear mixed effect methods for the individual and population pharmacokinetic parameters for mepolizumab from the sparse sampling. Blood samples for PK analyses of mepolizumab were collected on dosing days (Days 1, 28 and 56) at pre-dose and 0.5 h, 1 h and 2 h post-dose (time was relative to the end of infusion in the IV cohort) as well as on Days 3, 7, 70, 84, 112 and 140 (follow-up visit).

Assessment of the nasal polyposis condition was performed after six months of dosing to determine the situation indicative of a reduction in the need for surgery. The components used to determine the need for surgery were endoscopic polyp (ENP) scores and a severity of condition as measured by a visual analogue scale (VAS). Surgery was still deemed required for a participant with an ENP score of \>=3, or an ENP score of 2 and a VAS symptom score of \>7. The number of participants with reduced need for polyp surgery are presented as missing data set to non-responders (NR) and missing data last observation carry forward (LOCF). LOCF is defined as missing responses at Week 25 imputed with the last non-missing post-dose observation for that participant.

An AE is defined as any untoward medical occurrence in a participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. A serious adverse event is defined as any untoward medical occurrence that, at any dose that Results in death, life-threatening; requires hospitalization or prolongation of existing hospitalization; results in disability/incapacity; a congenital anomaly/birth defect. Drug-related AE's were considered to have a reasonable possibility of being related to treatment by the investigator. AE, SAE and drug-related AEs are summarized by TP and FP.

Blood samples were collected at Day 1, Weeks 4, 8, 12, 16, 20 and 24 to estimate the following biochemistry parameters: alanine amino transferase (ALT), aspartate amino transferase (AST), albumin (Ab), total protein (ToP), creatinine (Cr), total bilirubin (TB), calcium (Ca), bicarbonate (Bi), chloride (Cl), glucose (Glu), potassium (Pot), and sodium (Sod). Laboratory abnormalities outside the reference range (high and low values) at any time post baseline were presented. Any time post Baseline = all visits (including scheduled and unscheduled). If participant had given both high and low value at least once then participant is counted under both high and low category for this visit.

Blood samples were collected pre-infusion at Day 1, Week 4 and Week 8; and 24h and 72h post-infusion at Day 1, Week 4 and Week 8 time points and at Weeks 2, 6, 10, 12, 16, 20, 24, and 34 to estimate the following hematology parameters: basophils (Bas), percentage of basophils (% Bas), lymphocytes (Lym), percentage of Lym (% Lym), monocytes (Mon), percentage of Mon (% Mon), platelet count (PC), total neutrophils (TN), percentage of TN (% TN), white blood cell count (WBC), hematocrit (He), hemoglobin (Hg), and red blood cell count (RBC). Laboratory abnormalities outside the reference range (high and low values) at any time post baseline were presented. Any time post Baseline = all visits (including scheduled and unscheduled). If participant had given both high and low value at least once then participant is counted under both high and low category for this visit.

12-lead ECG assessments were obtained at the following time points: screening, and Weeks 4, 8 and 12.. Overall ECG findings were summarized using the worst case findings without regard to visits ie. "any time post Baseline". Change from Baseline in ECG findings were categorized as clinically significant change from Baseline; no clinically significant change from Baseline and not applicable.

SBP and DBP measurements were obtained at the following time points: screening, pre-infusion, 10 minutes (m), 30m, 1 hour (h), 2h post-infusion on Day 1, Week 4, Week 8; and Weeks 12, 16, 20 and 24. Screening value was considered as the Baseline value. Change from Baseline was calculated as the post-Baseline value minus the Baseline value.

Heart rate measurements were obtained at the following time points: Screening, pre-infusion, 10m, 30m, 1h, 2h post-infusion on Day 1, Week 4, Week 8; and Weeks 12, 16, 20 and 24. Screening value was considered as the Baseline value. Change from Baseline was calculated as the post-Baseline value minus the Baseline value.

Temperature measurements were obtained at the following time points: Screening, Day 1, and Weeks 4, 8, 12, 16, 20 and 24. Screening value was considered as the Baseline value. Change from Baseline was calculated as the post-Baseline value minus the Baseline value.

Blood samples for testing anti-mepolizumab antibodies were collected on Day 1, Week 4 and 8 Infusion Visit (before the IV infusion) and at Week 12, 24 and 34 Week follow-up visits. The presence of anti-human mepolizumab antibodies was assessed using an immunoelectrochemiluminescent (ECL) assay. To address transient positive results, an assessment of repeated results were made. For any visit category: results were considered as positive if it was positive at any visit during the study, and results were considered as negative if it were negative at all visits during the study. For repeat visit category: results were considered as postive if the result was positive at \>1 visit, and results were considered as negative if the result was negative at all visits or was positive at only one visit.

A responder was defined as a participant achieving a reduction in esophageal eosinophils to \<5 cells per HPF as the highest count of eosinophils per HPF in all the esophageal sites biopsied at Week 12, confirmed by biopsy at Week 12 or at an early withdrawal visit prior to Week 12. A worst case (WC) approach was considered, if a particiapant withdrew prematurely : If a particiapnt dropped out of the study without having a biopsy taken, due to lack of efficacy or an adverse event, their response was imputed as not achieved. Participants who withdrew, without a biopsy, for other reasons (e.g. lost to follow-up) were considered non-evaluable for the primary analysis. For participants who withdrew early from the study and had a biopsy, the biopsy was used to determine their response.

Volume of distribution is defined as the theoretical volume in which the total amount of drug is uniformly distributed to produce the desired plasma concentration of a drug. Central volume of distribution is a hypothetical volume into which a drug initially distributes upon administration. Peripheral volume of distribution is the sum of all tissue spaces outside the central compartment. Steady state volume of distribution (Vss) is the apparent volume of distribution at steady-state. Blood samples were obtained at pre-infusion and 5m, 2h, 24h, 72-96h post-infusion at Day 1, Weeks 4, 8; and Weeks 2, 6 10, 12, 16, 20, 24 and 34 from each participant to estimate central (V1) and periperial (V2) and Steady State (Vss) volume of distribution of mepolizumab.

Clearance is defined as the removal of drug from a volume of plasma in a given unit of time (drug loss from the body). Blood samples were obtained at pre-infusion and 5m, 2h, 24h, 72-96h post-infusion at Day 1, Weeks 4, 8; and Weeks 2, 6 10, 12, 16, 20, 24 and 34 from each participant to estimate plasma clearance of mepolizumab.

IL8 cytokine mRNA and protein expression

IL5 and thymic stromal lymphopoietin cytokine mRNA and protein expression

IL1 receptor mRNA and protein expression

E-cadherin

alpha-smooth muscle actin protein expression