A two-part, randomised, double-blind, placebo controlled, multi-centre study to investigate the use of mepolizumab (SB-240563) in reducing the need for surgery in subjects with severe bilateral nasal polyposis.
Nasal polyposis has long been known as chronic inflammatory disease of the nasal mucosa. This disease is characterized by the presence of polyps in the upper nasal cavity, originating from within the ostiomeatal complex. The presence of polyps can cause long-term symptoms such as prominent nasal obstruction, post-nasal drip, loss of smell, and discharge. These symptoms can impact greatly upon a patient's quality of life.The etiology of nasal polyposis is currently unknown. The aim of this present study is to investigate the use of mepolizumab in reducing the potential need for surgery in subjects with severe bilateral nasal polyposis. The study is split into two parts: Part A is the treatment phase and focuses on the reduction of the need for surgery by exploring the efficacy of six doses of mepolizumab (one dose every four weeks) on nasal polyposis. This dosing regime will build upon the previous PoC study by exploring the potential for increased clinical efficacy as assessed by the potential need for surgery, and also and increased duration of action as assessed by time to relapse. Part B is the follow-up phase and will assess post-treatment nasal polyposis dynamics with a focus on time to relapse. All subjects participating in this study will undergo a run-in period on a low dose of intranasal steroids (INS) prior to first dosing. INS will be continued throughout the study up until study exit. This is to reflect the real life circumstances in which mepolizumab is intended to be used as a therapy. The overall aim of the study design is to further assess the impact in the potential need for surgery and explore an appropriate mepolizumab therapeutic regimen strategy for the treatment of nasal polyposis. In this study, the assessment of nasal polyposis will be performed by means of combining endoscopic polyp score with subject reported symptoms. This approach reflects real-life clinical assessment of nasal polyposis. Also, this study incorporates condition specific and general medical questionnaires in order to obtain a better understanding of the impact of severe nasal polyposis of the subject's quality of life (QOL). This is in line with increasing focus in the medical field on the effects of medical conditions and treatments on the quality of life of patients (Fokkens et al 2007).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
109
750 mg of mepolizumab by IV infusion
Placebo by IV infusion
subjects will undergo a run-in period of 10 - 14 days on a low dose of Intranasal Steroids (INS).
GSK Investigational Site
Ghent, Belgium
GSK Investigational Site
Amsterdam, Netherlands
GSK Investigational Site
Cambridge, United Kingdom
GSK Investigational Site
London, United Kingdom
Number of Participants With a Reduced Need for Surgery at Week 25
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.
Time frame: Week 25
Number of Participants With Endoscopic Nasal Polyp (ENP) Score Dynamics at Weeks 1, 2, 5, 9, 13, 17, 21, and 25
Each nostril was assessed for polyps and graded at Weeks 1, 2, 5, 9, 13, 17, 21, and 25. The right and left nostrils were scored from 0 to 4, where, 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 ENP score was recorded for both the right and the left nostril. The higher of the two scores was derived and used for the analysis. The ENP score ranges from 0 to 4, with a higher score indicating a larger polyp.
Time frame: Weeks 1, 2, 5, 9, 13, 17, 21, and 25
Number of Participants Who Required Polyp Surgery at Weeks 1, 2, 5, 9, 13, 17, 21, and 25
Assessment of the nasal polyposis condition was performed after 6 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 scores and a severity of condition as measured by a VAS. Surgery was required for participants with ENP scores of \>=3, or ENP scores of 2 and a VAS symptom score of \>7.
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GSK Investigational Site
London, United Kingdom
GSK Investigational Site
London, United Kingdom
Time frame: Weeks 1, 2, 5, 9, 13, 17, 21, and 25
Mean Change From Baseline in Systolic Blood Pressure (SBP) and Diastolic Blood Pressure (DBP) at Weeks 2, 5, 9, 13, 17, 21, and 25
SBP and DBP were measured at Baseline (Week 1) and at Weeks 2, 5, 9, 13, 17, 21, and 25. Baseline is defined as the Week 1 pre-dose assessment. Change from Baseline is defined as the difference between the post-dose post-Baseline visit value and the Baseline value.
Time frame: Baseline and Weeks 2, 5, 9, 13, 17, 21, and 25
Mean Change From Baseline in Pulse Rate at Weeks 2, 5, 9, 13, 17, 21, and 25
Pulse rate was measured at Baseline (Week 1) and at Weeks 2, 5, 9, 13, 17, 21, and 25. Baseline is defined as the Week 1 pre-dose assessment. Change from Baseline is defined as the difference between the post-dose post-Baseline visit value and the Baseline value.
Time frame: Baseline and Weeks 2, 5, 9, 13, 17, 21, and 25
Number of Participants With the Indicated Electrocardiogram (ECG) Findings at Weeks 1, 2, 5, 9, 13, 17, 21, and 25
A single safety 12-lead ECG was performed using a standard 12-lead ECG machine at Weeks 1, 2, 5, 9, 13, 17, 21, and 25. Any abnormal clinically significant (CS) and not clinically significant (NCS) findings were identified. ECG abnormaility with respect to CS and NCS findings were judged by the investigator or appropriately qualified designee. Clinically significant abnormal findings are those which are not associated with the underlying disease, unless judged by the investigator to be more severe than expected for the participant's condition.
Time frame: Weeks 1, 2, 5, 9, 13, 17, 21, and 25
Absolute Values of Clinical Chemistry Parameters Including Blood Urea Nitrogen (BUN), Glucose Fasting, Chloride, Sodium, Potassium, Carbon Dioxide, and Calcium at Weeks 1, 2, 5, 9, 13, 17, 21, and 25
BUN, glucose fasting, chloride, sodium, potassium, carbon dioxide (CO2), and calcium were assessed at Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose).
Time frame: Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose)
Absolute Values of the Clinical Chemistry Parameters of Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST), Alkaline Phosphatase (ALP), and Gamma Glutamyltransferase (GGT) at Weeks 1, 2, 5, 9, 13, 17, 21, and 25
ALT, AST, ALP, and GGT were assessed at Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose).
Time frame: Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose)
Absolute Values of the Clinical Chemistry Parameters of Albumin and Protein at Weeks 1, 2, 5, 9, 13, 17, 21, and 25
Albumin and protein were assessed at Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose).
Time frame: Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose)
Absolute Values of the Clinical Chemistry Parameters of Total and Direct Bilirubin, Creatinine (CRT), and Uric Acid (UA) at Weeks 1, 2, 5, 9, 13, 17, 21, and 25
Total bilirubin (TB) and direct bilirubin (DB), creatinine, and uric acid were assessed at Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose).
Time frame: Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose)
Absolute Values of the Hematology Parameters of Platelet Count and White Blood Cell (WBC) Count, Basophils, Eosinophils, Lymphocytes, Monocytes, and Neutrophils at Weeks 1, 2, 5, 9, 13, 17, 21, and 25
Platelet count, WBC count, basophils, eosinophils, lymphocytes, monocytes, and neutrophils were assessed at Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose).
Time frame: Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose)
Absolute Values of the Hematology Parameters of Hemoglobin and Mean Corpuscular Hemoglobin Concentration (MCHC) at Weeks 1, 2, 5, 9, 13, 17, 21, and 25
Hemoglobin and MCHC were assessed at Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose).
Time frame: Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose)
Absolute Values of the Hematology Parameter of Red Blood Cell (RBC) Count and Reticulocyte Count (RC) at Weeks 1, 2, 5, 9, 13, 17, 21, and 25
RBC count and RC were assessed at Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose).
Time frame: Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose)
Absolute Values of the Hematology Parameter of Mean Corpuscular Hemoglobin (MCH) at Weeks 1, 2, 5, 9, 13, 17, 21, and 25
MCH was assessed at Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose).
Time frame: Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose)
Absolute Values of the Hematology Parameter of Mean Corpuscular Volume (MCV) at Weeks 1, 2, 5, 9, 13, 17, 21, and 25
MCV was assessed at Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose).
Time frame: Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose)
Absolute Value of the Hematology Parameter of Reticulocyte Count/Erythrocyte Uncorrected at Weeks 1, 2, 5, 9, 13, 17, 21, and 25
Reticulocyte count was assessed at Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose).
Time frame: Week 1 pre-dose, Week 2, Week 5 pre-dose, Week 9 pre-dose, Week 13 pre-dose, Week 17 pre-dose, Week 21 pre-dose, and Week 25 (4 Weeks post last dose)
Number of Participants With Positive Clinically Relevant Urinalysis Results at Weeks 1, 2, 5, 9, 13, 17, 21, and 25
Specific gravity, power of hydrogen (pH), glucose, protein, blood, and ketones were assessed at Weeks (Wk) 1, 2, 5, 9, 13, 17, 21, and 25. Results for all urinalysis parameters were assessed for clinical relevance by physician. Clinically relevant positive results are presented. Clinically relevant positive results are defined as those which are not associated with the underlying disease, unless judged by the investigator to be more severe than expected for the participant's condition.
Time frame: Weeks 1, 2, 5, 9, 13, 17, 21, and 25
Number of Participants With Any Treatment-emergent Adverse Event (AE) and Serious Adverse Event (SAE)
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. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a medicinal product. An 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, is an important medical event that jeopardizes the participants or may require medical or surgical intervention to prevent one of the other outcomes listed in the above definition, or is associated with liver injury and impaired liver function.
Time frame: Up to 11 months
Mean of the Forced Expiratory Volume in 1 Second (FEV1) at Weeks 2, 5, 9, 13, 17, 21, and 25
FEV1 is defined as the volume of air forcefully expelled from the lungs in one second. FEV1 measurements were taken by spirometry at each clinic visit. FEV1 was calculated as the maximum of three readings taken at each time point for each participant. Spirometry data is plotted and analyzed using a repeated measures model to calculate treatment difference, confidence intervals and p-values.
Time frame: Weeks 2, 5, 9, 13, 17, 21, and 25
Mean of Forced Vital Capacity (FVC) at Weeks 2, 5, 9, 13, 17, 21, and 25
FVC is defined as the maximum amount of air that can forcibly be blown out after a maximum inspiration. FVC was calculated as the maximum of three readings taken at each time point for each participant. Spirometry data are plotted and analyzed using a repeated measures model to calculate treatment difference, confidence intervals and p-values.
Time frame: Weeks 2, 5, 9, 13, 17, 21, and 25
Mean Peak Expiratory Flow Rate (PEFR) at Indicated Weeks 2, 5, 9, 13, 17, 21, and 25
PEFR is defined as the maximum airflowrate generated during a forced expiration beginning with the lungs fully inflated. PEFR was calculated as the maximum of three readings taken at each time point for each participant. Spirometry data is plotted and analyzed using a repeated measures model to calculate treatment difference, confidence intervals and p-values.
Time frame: Weeks 2, 5, 9, 13, 17, 21, and 25
Individual Symptoms Visual Analogue Scale (VAS) Scores at Weeks 1, 2, 5, 9, 13, 17, 21, and 25
Participants were asked to indicate on a VAS (0 to 10 centimeters) the severity of nasal polyposis and its four symptoms (one VAS for each symptom): rhinorrhea; mucus in the throat; nasal blockage; loss of smell. The left-hand side of the scale (0) represents "not troublesome," and the right hand side of the scale (10) represents "worst possible troublesome." Hence the score ranges between 0 to 10, with higher scores indicating greater severity.
Time frame: Weeks 1, 2, 5, 9, 13, 17, 21, and 25
Mean Peak Nasal Inspiratory Flow (PNIF) at Weeks 2, 5, 9, 13, 17, 21, and 25
Participants used a portable hand-held inspiratory flow meter to measure and record PNIF in the morning prior to taking the study medication. Three measurements were taken, and the largest measurement was recorded in the electronic diary. PNIF data is plotted and analyzed using a repeated measures model to calculate treatment difference, confidence intervals and p-values.
Time frame: Weeks 2, 5, 9, 13, 17, 21, and 25
Olfaction Testing: Worst Nostril Score (WNS) and Mean Nostril Score (MNS) at Weeks 2, 5, 9, 13, 17, 21, and 25
Sniffin'Sticks were used to assess each participant's sense of smell (olfaction). Olfaction testing results were recorded for both the right and left nostrils The worst nostril score (number of correct answers for the worst nostril) and the mean nostril score (mean number of correct answers across both nostrils) were recorded. Scores range from 0 to 12 (high score indicating normal olfactory sensation). Olfaction data are plotted and analyzed using a repeated measures model to calculate treatment difference, confidence intervals and p-values.
Time frame: Weeks 2, 5, 9, 13, 17, 21, and 25
Sino-Nasal Outcome Test (SNOT)-22 Questionnaire Total Score at Week 25 (Adjusted for Week 1 Baseline)
SNOT-22 questionnaire is a modification of the SNOT-20 and contains the questions (ques) related to smell and nasal obstruction. Each ques is graded with a numerical score for each response (resp); scores range from 0 for "no symptoms" to 5 for "as bad as things could be." Scores for each of the ques is summed to derive the total score for that par. at that visit. If the par. did not complete any ques at a visit, then he/she were not to have any missing values imputed, and his/her total score for that visit was set to missing. If a par. had some missing scores (but no more than 50% missing at that visit), then scores for the missing resp were imputed as the mean of the non-missing resp for that par. at that visit. The SNOT-22 total score ranges from 0 to 110, with higher scores representing a worse quality of life. Questionnaire data analysis was done using an ANCOVA to obtain the LS-means, treatment difference and confidence interval at Week 25, adjusting for Week 1 Baseline scores.
Time frame: Week 1 (Baseline) and Week 25
Index Score of the EuroQoL Quality of Life-5D (EQ-5D) Questionnaire at Week 25 (Adjusting for Week 1 Baseline Scores)
The EQ-5D is a standardized, 2-part questionnaire used to measure health outcomes. The first part contains descriptions of the following five components: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Responses to each of the five domains are measured on a 3-point scale (1-no problems, 2-some problems, and 3-severe problems). An index for the descriptive scores was derived using the general European weights, obtained for each of the countries in this study. Index scores were derived for each participant at each time point by taking sum of weights. Index score ranges from -0.718 to 1, with lower scores indicating poor health. ANCOVA model with treatment, Baseline (Week 1 scores) and country as factors was used to calculate treatment difference and confidence intervals at Week 25.
Time frame: Week 1 (Baseline) and Week 25
VAS Score of the EQ-5D Questionnaire at Week 25 (Adjusting for Week 1 Baseline Scores)
The EQ-5D is a standardized, 2-part questionnaire used to measure health outcomes. The second part of the questionnaire is a VAS question, requiring the participant to self rate his/her health score on a scale of 0 (worst imaginable health state) to 100 (best imaginable health state). ANCOVA model with treatment, Baseline (Week 1 scores) and country as factors was used to calculate treatment difference and confidence intervals at Week 25.
Time frame: Week 1 (Baseline) and Week 25
Systemic Clearance of Mepolizumab 750 mg
Blood samples were collected for the assessment of systemic clearance at Weeks 1, 2, 5, 9, 13, and 25. Systemic Clearance (CL) is estimated using a population-Pharmacokinetic model incorporating all available data points from all participants. Individual values were estimated from the model as post-hoc values after incorporating between-participant variability.
Time frame: Weeks 1, 2, 5, 9, 13, and 25
Volume of Distribution of Mepolizumab 750 mg
Volume of distribution at steady-state was derived from pharmacokinetic parameter estimates of a population pharmacokinetic model. Blood samples were collected for analysis of volume of distribution at Weeks 1, 2, 5, 9, 13, and 25. All available concentrations at all available datapoints from all participants were incorporated into the model. Individual values were estimated from the model as post-hoc values after incorporating between-participant variability.
Time frame: Weeks 1, 2, 5, 9, 13, and 25
Bodyweight-adjusted Clearance
Clearance is the volume of plasma that would contain the amount of drug excreted per day. Blood samples were collected for the assessment of bodyweight-adjusted clearance at Weeks 1, 2, 5, 9, 13, and 25. Clearance was estimated using a population-pharmacokinetic model incorporating all available data points from all participants. Individual values were estimated from the model as post-hoc values after incorporating between-participant variability.
Time frame: Weeks 1, 2, 5, 9, 13, and 25
Steady-State Volume of Distribution
Steady-state volume of distribution is the blood and tissue volume into which a drug is distributed and the relative binding of drug to protein in these spaces. Blood samples were collected for the assessment of steady-state volume of distribution at Weeks 1, 2, 5, 9, 13, and 25. Steady-state volume of distribution was estimated using a population-pharmacokinetic model incorporating all available data points from all participants. Individual values were estimated from the model as post-hoc values after incorporating between-participant variability.
Time frame: Weeks 1, 2, 5, 9, 13, and 25
Maximum Observed Plasma Drug Concentration (Cmax), Average Concentration (Cav[0-inf]), and Steady State Maximum Observed Plasma Drug Concentration (Cmax SS)
Blood samples were collected for the assessment of Cmax, Cav(0-inf), and Cmax SS at Weeks 1, 2, 5, 9, 13, and 25. These parameters were estimated using a population-pharmacokinetic model incorporating all available data points from all participants. Individual values were estimated from the model as post-hoc values after incorporating between-participant variability.
Time frame: Weeks 1, 2, 5, 9, 13, and 25
Area Under the Plasma Drug Concentration Versus Time Curve From Time 0 Extrapolated to Infinite Time (AUC[0-inf])
Blood samples were scheduled to be collected for the assessment of AUC(0-inf) at Weeks 1, 2, 5, 9, 13, and 25 AUC\[0-inf\] is derived from individual systemic clearance estimates using the expression AUC\[0-inf\] = Dose/CL. Hence all data are incorporated into the estimation of CL and by implication AUC\[0-inf\].
Time frame: Weeks 1, 2, 5, 9, 13, and 25
Half-life (Alpha) and Half-life (Beta)
Half-life (Alpha) is the rate of decline in plasma concentrations due to the process of drug redistribution from the central to the peripheral compartment and half-life (Beta ) is the rate of decline due to the process of drug elimination due to metabolism. Blood samples were collected for the assessment of half-life (Alpha) and half-life (Beta) at Weeks 1, 2, 5, 9, 13, and 25. Half-life was estimated using a population-pharmacokinetic model incorporating all available data points from all participants. Individual values were estimated from the model as post-hoc values after incorporating between-participant variability.
Time frame: Weeks 1, 2, 5, 9, 13, and 25
Pharmacokinetic/Pharmacodynamic (PK/PD) Model Derived Baseline
Blood samples were collected for the assessment of PK/PD model derived Baseline at Weeks 1, 2, 5, 9, 13, 17, 21 and 25. An exploratory Emax direct response model was fitted to serial blood eosinophil count data (including placebo) using model-predicted mepolizumab concentrations (with zero imputed for placebo treated participants). All available blood eosinophil count data were incorporated into the model. Individual values were estimated from the model as post-hoc values after incorporating between-participant variability.
Time frame: Weeks 1, 2, 5, 9, 13, 17, 21 and 25
PK/PD Model Derived Coefficient of Variation of Baseline (CV[Baseline]), Variation of Maximal Effect of Drug (CV[Emax]), and Residual
A residual is the difference between the observed and predicted values. Blood samples were collected for the assessment of PK/PD model derived CV(Baseline), CV(Emax), and residual at Weeks 1, 2, 5, 9, 13, 17, 21 and 25. An exploratory Emax direct response model was fitted to serial blood eosinophil count data (including placebo) using model-predicted mepolizumab concentrations (with zero imputed for placebo treated subjects). All available datapoints were incorporated into the model. Individual values are estimated from the model as post-hoc values after incorporating between-participant variability.
Time frame: Weeks 1, 2, 5, 9, 13, 17, 21 and 25
PK/PD Model Derived Half Maximal Effective Drug Concentration (EC50)
Blood samples were collected for the assessment of PK/PD model derived EC50 at Weeks 1, 2, 5, 9, 13, 17, 21 and 25. An exploratory Emax direct response model was fitted to serial blood eosinophil count data (including placebo) using model-predicted mepolizumab concentrations (with zero imputed for placebo treated participants). All available datapoints were incorporated into the model. Individual values are estimated from the model as post-hoc values after incorporating between-partcipant variability.
Time frame: Weeks 1, 2, 5, 9, 13, 17, 21 and 25
PK/PD Model Derived Maximum Inhibition
Blood samples were collected for the assessment of Maximum Inhibition at Weeks 1, 2, 5, 9, 13, 17, 21 and 25. An exploratory Emax direct response model was fitted to serial blood eosinophil count data (including placebo) using model-predicted mepolizumab concentrations (with zero imputed for placebo treated participants). All available datapoints were incorporated into the model. Individual values are estimated from the model as post-hoc values after incorporating between-participant variability.
Time frame: Weeks 1, 2, 5, 9, 13, 17, 21 and 25
Number of Participants With Positive Immunogenicity (Anti-mepolizumab Antibody Testing)
Blood samples were collected at Week 1 pre-dose, Week 5 pre-dose, Week 13 pre-dose and Week 25 (4 weeks post last dose) for anti-mepolizumab antibody testing using a validated electrochemiluminescent (ECL) immunoassay. The assay involved screening, confirmation and titration steps. If serum samples tested positive in the screening assay, they were considered 'potentially positive' and were further analyzed for the specificity using the confirmation assay. Samples that confirmed positive in the confirmation assay were reported as 'positive'.
Time frame: Week 1 pre-dose, Week 5 pre-dose, Week 13 pre-dose and Week 25 (4 weeks post last dose)