Mepolizumab Long-term Study to Assess Real World Safety and Effectiveness of Eosinophilic Granulomatosis With Polyangiitis (EGPA) in Japan

An AE is any untoward medical occurrence in a clinical study participant, temporally associated with study participation, whether or not considered related to study participation. An SAE is defined as any untoward medical occurrence that, at any dose: results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent disability/incapacity, is a congenital anomaly/birth defect, and other situations which involve medical or scientific judgment. An AESI may be of scientific and medical concern related to the treatment, monitored, and rapidly communicated by investigator to sponsor. AESIs included Hypersensitivity (including anaphylaxis), Infections and Malignant tumors.

An ADR is defined as an AE for which the investigator classifies the possible relationship to study intervention as "Yes". ADRs related to NUCALA were collected.

Clinical symptoms as assessed by 9 organ-systems (i.e. systemic, skin, mucous membranes/eyes, ears/nose/throat, chest, cardiovascular, abdominal, renal, nervous system [motor and sensory]) relevant to EGPA in systemic vasculitis were assessed. Data were summarized for following categories; none, active, worsening, active + worsening. "None" is defined as absence of clinical symptoms. "Active disease" is defined as follows: The participant has clinical symptoms, or worsening of symptoms is noted as compared to those in the preceding observation period and the status in the preceding observation period was assessed as "None". "Worsening" is defined as follows: The participant has worsening clinical symptoms, or worsening of symptoms is noted as compared to those in the preceding observation period and the status in the preceding observation period was assessed as "Active disease" or "Worsening". Percentage values are rounded off.

EGPA relapse is defined as any of the following with worsening EGPA: increased dose of oral corticosteroids (OCS), initiation/increased dose of immuno-suppressive agents or EGPA treatment with hospitalization. Percentage of participants with EGPA relapse were reported. Percentage values are rounded off.

Annualized rate of hospitalization = (Number of corresponding hospital visits * 365)/ (number of days in the observation period). The annualized rate and associated 95 percent (%) confidence intervals (CIs) were calculated using a negative binomial generalized linear model with logarithm of time as an offset variable, without covariate. Number (estimated event per person year) and 95% CI were reported.

Annualized rate of Emergency Room/Unscheduled Visit = (Number of corresponding Emergency Room/Unscheduled Visits * 365)/(number of days in the observation period). The annualized rate and associated 95% CIs were calculated using a negative binomial generalized linear model with logarithm of time as an offset variable, without covariate. Number (estimated event per person year) and 95% CI were reported.

Average daily dose of OCS for each participant was calculated by 12-weekly periods as: Total dosage of OCS (mg) / Total duration of administration of OCS (day). Total duration of administration is defined as: Last date of period minus later date of (first date of each period or start date of OCS) +1.

Number of participants by each category of average daily prednisolone-equivalent of OCS were assessed. The dosing categories included: zero, greater than (>)0 to less than or equal to (<=) 4.0 milligrams per day (mg/day), >4.0 to <=7.5 mg/day, >7.5 mg/day.