DEGS - Dupilumab for Eosinophilic Gastritis Study

This is a phase 2, multi-center, randomized, double-blind, placebo-controlled trial testing
the efficacy of dupilumab vs. placebo in EG. Qualifying subjects will be randomized 1:1 to
either study drug (dupilumab) or placebo, and will receive 600 mg once followed by 300 mg
doses every two weeks of study treatment for a total of 6 injections. After the 6th injection
subjects may continue into an open-label treatment phase in which dupilumab will be
administered every two weeks for a total of 24 weeks.

Approximately nine sites associated with the Consortium of Eosinophilic Gastrointestinal
Disease Researchers (CEGIR) will take part in the study.

The primary objective of this study is to assess the efficacy of repeat subcutaneous (SC)
doses of dupilumab, compared with placebo, to reduce eosinophilic inflammation in the
gastrointestinal tract of patients with EG.

Inclusion Criteria:

- Able to give written informed consent

- Willing and able to comply with study visits and activities.

- Age 18-70 years at study enrollment

- Histologically active EG at time of screening, with a peak Gastric count of ≥ 30
eos/hpf in at least 5 hpfs, with no other known cause for gastric eosinophilia;
involvement of eosinophilic inflammation in other gastrointestinal segments will be
allowed but not required or sufficient.

- Ongoing clinical symptoms (i.e., abdominal pain, bloating, vomiting, diarrhea) prior
to enrollment that are not adequately managed by current therapeutic regimen, in the
opinion of the patient and investigator.

- Stable medical management of EG (and other eosinophilic disorders, if applicable)
including stable dosage of medications in the 30 days prior to study enrolment.
Subjects may be on baseline anti-EG therapy (such as elimination diet, elemental diet,
proton pump inhibitors, topical or systemic glucocorticoids, immunosuppressive agents,
cromolyn, and anti-histamines) as long as there is agreement not to change their
dosage unless medically indicated.

- Willing to maintain current dietary regimen throughout the course of the study.

- Women of childbearing potential (WOCBP) and male subjects who are sexually active and
non-sterile must agree to use an acceptable method of contraception from Screening
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

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

- 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 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 was
obtained.

- Current or recent use of biological agents (<5 half-lives prior to screening)

- Current or recent use of any investigational drug (30 days or 5 half-lives, whichever
is longer, prior to screening)

- History of anaphylaxis to any biologic therapy or vaccine

- Current pregnancy or breastfeeding

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

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

- Any other medical illness that precludes study involvement