Study of Mepolizumab Safety Syringe in Asthmatics

Inclusion Criteria:

- Age: At least 12 years of age inclusive, at the time of signing the informed consent.
For those countries where local regulations permit enrolment of adults only, subject
recruitment will be restricted to those who are >=18 years of age.

- Asthma: A physician diagnosis of asthma for >=2 years that meets the National Heart,
Lung and Blood Institute guidelines or Global Initiative for Asthma guidelines.

- Mepolizumab treatment:

a. Not receiving mepolizumab treatment at Visit 1. These subjects must also meet
following inclusion criteria related to eosinophilic asthma, inhaled corticosteroid,
controller medication and exacerbation history):

- Eosinophilic asthma: A high likelihood of eosinophilic asthma as per the required
'Continuation to Treatment'-criterion,

- Inhaled corticosteroid: A well-documented requirement for regular treatment with high
dose inhaled corticosteroid (ICS) in the 12 months prior to Visit 1 with or without
maintenance oral corticosteroids (OCS), for subjects >=18 years old, ICS dose must be
>=880 micrograms (mcg)/day fluticasone propionate (FP) (ex-actuator) or equivalent
daily, For ICS/long-acting-beta-2-agonist (LABA) combination preparations, the highest
approved maintenance dose in the local country will meet this ICS criterion, for
subjects >=12 to <=17 years old, ICS dose must be >=440 mcg/day FP (ex-actuator) or
equivalent daily, for ICS/LABA combination preparations, the mid-strength approved
maintenance dose in the local country will meet this ICS criterion.

- Controller medication: Current treatment with an additional controller medication,
besides ICS, for at least 3 months or a documented failure in the past 12 months of an
additional controller medication (e.g., LABA, leukotriene receptor antagonist [LTRA],
or theophylline) for at least 3 successive months.

- Exacerbation history: Previously confirmed history of one or more exacerbations
requiring treatment with systemic corticosteroid (CS) [intramuscular (IM),
intravenous, or oral] in the 12 months prior to Visit 1, despite the use of high-dose
ICS. For subjects receiving maintenance CS, the CS treatment for an exacerbation must
have been a two-fold dose increase or greater.

or, b. Receiving 100 mg SC mepolizumab administered for the treatment of severe
eosinophilic asthma every 4 weeks for at least 12 weeks prior to Visit 1.

- Body weight: A minimum body weight >=40 kilograms (kg) at Visit 1

- Gender: Male or female. A female subject is eligible to participate if she is not
pregnant (as confirmed by a negative urine human chorionic gonadotrophin [hCG)]test),
planning to become pregnant during the time of study participation (and up to 16 weeks
after the last dose), not lactating, and at least one of the following conditions
applies: Non-reproductive potential defined as: pre-menopausal females with documented
tubal ligation or documented hysteroscopic tubal occlusion procedure with follow-up
confirmation of bilateral tubal occlusion or hysterectomy or documented bilateral
oophorectomy, postmenopausal female, reproductive potential and agrees to follow
highly effective methods for avoiding pregnancy in females of reproductive potential
from 30 days prior to the first dose of study medication and until 16 weeks after the
last dose of study medication and completion of the end of study/early withdrawal
visit. The investigator is responsible for ensuring that subjects understand how to
properly use these methods of contraception.

- Informed consent: Capable of giving signed informed consent.

Exclusion Criteria

- Presence of a known pre-existing, clinically important lung condition other than
asthma. This includes current infection, bronchiectasis, pulmonary fibrosis,
bronchopulmonary aspergillosis, or diagnoses of emphysema or chronic bronchitis
(chronic obstructive pulmonary disease other than asthma) or a history of lung cancer.

- Subjects with other conditions that could lead to elevated eosinophils such as
Hypereosinophilic Syndromes, including Churg-Strauss Syndrome, or Eosinophilic
Esophagitis. Subjects with a known, pre-existing parasitic infestation within 6 months
prior to Visit 1 are also to be excluded.

- A current malignancy or previous history of cancer in remission for less than 12
months prior to screening (Subjects that had localized carcinoma of the skin which was
resected for cure will not be excluded).

- A known immunodeficiency (e.g. human immunodeficiency virus - HIV), other than that
explained by the use of corticosteroids taken as therapy for asthma.

- Subjects who have known, pre-existing, clinically significant cardiovascular,
endocrine, autoimmune, metabolic, neurological, renal, gastrointestinal, hepatic,
haematological or any other system abnormalities that are uncontrolled with standard
treatment.

- Known, pre-existing, unstable liver disease (as defined by the presence of ascites,
encephalopathy, coagulopathy, hypoalbuminaemia, esophageal or gastric varices or
persistent jaundice), cirrhosis, and known biliary abnormalities (with the exception
of Gilbert's syndrome or asymptomatic gallstones)

- QT interval corrected for heart rate by either Fridericia's or Bazett's formula
QTc(F)/QTc(B) ≥450milliseconds (msec) or QTc(F)/QTc(B) ≥480 msec for subjects with
Bundle Branch Block at Visit 1 confirmed by electrocardiogram (ECG).

- Subjects who have received omalizumab within 130 days of Visit 1.

- Subjects who have received any monoclonal antibody (other than Xolair) to treat
inflammatory disease within 5 half-lives of Visit 1.

- Subjects who have received treatment with an investigational drug, other than
mepolizumab within the past 30 days or five terminal phase half-lives of the drug
whichever is longer, prior to visit 1 (this also includes investigational formulations
of marketed products) or experimental anti-inflammatory drugs (non biologicals) in the
past 3 months.

- Subjects who have received chemotherapy within 12 months prior to Visit 1.

- A history (or suspected history) of alcohol misuse or substance abuse within 2 years
prior to Visit 1.

- Subjects with hypersensitivity to mepolizumab or to any of the excipients (sodium
phosphate, citric acid, sucrose, ethylenediamine tetraacetic acid (EDTA), polysorbate
80).

- Subjects who have known evidence of lack of adherence to controller medications and/or
ability to follow physician's recommendations.