MEA112997 Open-label Long Term Extension Safety Study of Mepolizumab in Asthmatic Subjects

Inclusion Criteria:

- Informed Consent.

- MEA112997 Study Participation: Received at least 2 doses of double-blind
investigational product during the MEA112997 trial.

- MEA112997 Treatment Assignment: If the subject received mepolizumab, they must have
had a positive risk: benefit ratio.

- Currently being treated with a controller medication and the subject has been on a
controller medication for the past 12 weeks.

- Male or Eligible Female Subjects. To be eligible for entry into the study, females of
childbearing potential must commit to consistent and correct use of an acceptable
method of birth control for the duration of the trial and for 4 months after the last
study drug administration.

Exclusion Criteria:

- Hypersensitivity related to mepolizumab.

- Clinically significant change in health status since completing participation in the
MEA112997 trial.

- A current malignancy or previous history of cancer in remission for less than 12
months prior to screening.

- For those subjects who had a SAE in MEA112997 that was assessed as possibly related to
mepolizumab by the investigator.

- Subjects who are pregnant or breastfeeding. Subjects should not be enrolled if they
plan to become pregnant during the time of study participation.

- Screening ECG which has a clinically significant abnormality.

- Received Xolair (omalizumab) within the past 130 days.

- Participated in a clinical trial within the past 30 days or have received
investigational medication within five terminal half-lives of Screen Visit, whichever
is longer.

- Current smokers.