Benralizumab for Eosinophilic Gastritis

Primary Objective:

To assess the efficacy of repeat subcutaneous (SC) doses of benralizumab, compared with
placebo, to reduce eosinophilic inflammation in the gastrointestinal tract of patients with
EG Secondary Objectives: To assess changes in endoscopic score/histological features/blood
and biopsy eosinophil counts/clinical symptoms/esophageal, gastric, and duodenal tissue
transcriptome changes/ before and after treatment with benralizumab.

26 subjects are planned to be enrolled into the study at Cincinnati Children's Hospital
Medical Center.

Qualifying Subjects will receive 3 monthly sub-coetaneous injections of benralizumab/Placebo,
followed by an option six month Open Label Extension period.

Inclusion Criteria:

- Informed Consent: Able to give written informed consent prior to participation in the
study, which will include the ability to comply with the requirements and restrictions
listed in the consent form. Subjects must be able to read, comprehend, and write at a
level sufficient to complete study related materials.

- Males and females between the ages of 12-60 years with confirmed diagnosis of EG
involving stomach; involvement of eosinophilic inflammation in other gastrointestinal
segments will be allowed but not required or sufficient.

- Histologically active EG at time of screening, with a peak Gastric count of ≥ 30
eos/hpf in at least 5 hpfs.

- Must be symptomatic (defined as having experienced symptoms within 4 weeks prior to
enrollment)

- Blood eosinophilia (defined as having an absolute eosinophil count > 500 cells per mcL
of blood ) at least once during the 6 months prior to enrollment.

- Must be on baseline anti-EG/EGE therapy as long as there is agreement to not change
their dosage unless medically indicated.

- Clinical symptoms (i.e., abdominal pain, bloating, vomiting, diarrhea) severe enough
to impact daily life (e.g., school/work attendance, social activities) ≥ 2 days/week
for 3 of the 4 weeks prior to enrollment despite treatment (such as diet, proton pump
inhibitors or corticosteroids). See addendum number 1, page 55.

- Female subjects: Women of childbearing potential (WOCBP) must use an effective form of
birth control (confirmed by the Investigator). Effective forms of birth control
include: true sexual abstinence, a vasectomized sexual partner, Implanon, female
sterilization by tubal occlusion, any effective IUD intrauterine device/IUS
levonogestrel Intrauterine system, Depo-Provera(tm) injections, oral contraceptive,
and Evra Patch(tm) or Nuvaring(tm). WOCBP must agree to use effective method of birth
control, as defined above, from enrollment, throughout the study duration and within
16 weeks after last dose of IP, and have negative serum pregnancy test result on Visit
0.

- Women not of childbearing potential are defined as women who are either permanently
sterilized (hysterectomy, bilateral oophorectomy, or bilateral salpingectomy), or who
are postmenopausal. Women will be considered postmenopausal if they have been
amenorrheic for 12 months prior to the planned date of visit -1 without an alternative
medical cause. The following age-specific requirements apply:

- Women <50 years old would be considered postmenopausal if they have been amenorrheic
for 12 months or more following cessation of exogenous hormonal treatment and follicle
stimulating hormone (FSH) levels in the postmenopausal range.

- Women ≥50 years old would be considered postmenopausal if they have been amenorrheic
for 12 months or more following cessation of all exogenous hormonal treatment.

- All male subjects who are sexually active must agree to use an acceptable method of
contraception (condom with or without spermicide, vasectomy) from Visit 0 until 16
weeks after their last dose.

Exclusion Criteria:

- Concurrent H. pylori gastritis or parasitic infection

- Other gastrointestinal disorders such as Crohn's disease, inflammatory bowel disease,
or Celiac disease

- Esophageal stricture that prevents the easy passage of a standard endoscope

- Use of any investigational biologic drug within 6 months prior to screening

- Hypereosinophilic syndrome, defined by multiple organ involvement (with the exception
of atopic disease or EGID) and persistent blood absolute eosinophil count ≥1500/mcL.

- A diagnosis of celiac disease, inflammatory bowel disease, eosinophilic granulomatosis
with polyangiitis (EGPA), drug hypersensitivity or connective tissue rheumatological
disorders,

- History of cancer: Subjects who have had basal cell carcinoma, localized squamous cell
carcinoma of the skin, or in situ carcinoma of the cervix are eligible provided that
the subject is in remission and curative therapy was completed at least 12 months
prior to the date informed consent, and assent when applicable was obtained. Subjects
who have had other malignancies are eligible provided that the subject is in remission
and curative therapy was completed at least 5 years prior to the date informed
consent, and assent when applicable, was obtained.

- A helminth parasitic infection diagnosed within 24 weeks prior to the date informed
consent is obtained that has not been treated with, or has failed to respond to
standard of care therapy.

- Pregnant or nursing

- Receipt of any investigational non-biologic within 30 days or 5 half-lives prior to
visit 0, whichever is longer.

- A history of known immunodeficiency disorder including a positive human
immunodeficiency virus (HIV) test.

- Any other medical illness that precludes study involvement

- Positive hepatitis B surface antigen, or hepatitis C virus antibody serology, or a
positive medical history for hepatitis B or C. Subjects with a history of hepatitis B
vaccination without history of hepatitis B are allowed to be enrolled.

- Patients who are currently receiving or have previously received benralizumab or any
other type of anti-interleukin therapy (i.e. mepolizumab, reslizumab, lebrikizumab
etc.) within the last 6 months or 5 half-lives whichever is longer.

- History of anaphylaxis to any biologic therapy or vaccine.

- Receipt of immunoglobulin or blood products within 30 days prior to the date informed
consent is obtained.