A Phase 3, Randomized, Double-Blind, Placebo-Controlled Multicenter Study of Itolizumab in Combination with Corticosteroids for the Initial Treatment of Acute Graft Versus Host Disease

This is a multi-center study to compare the efficacy and safety of itolizumab versus placebo
as first-line therapy for subjects with Grade III-IV aGVHD or Grade II with LGI involvement,
in combination with corticosteroids

Inclusion Criteria:

1. Is willing and able to provide written informed consent/assent and to comply with all
protocol procedures and assessments required for the study.

2. Is age ≥12 years and >40kg at informed consent/assent.

3. Has had an initial allogeneic HSCT for any indication using any graft source, donor
source, conditioning regimen intensity or prophylaxis.

4. Has evidence of myeloid engraftment

5. Has a clinical diagnosis of aGVHD Grades III-IV or Grade II with LGI involvement based
on Mount Sinai Acute GVHD International Consortium (MAGIC) grading criteria.

6. Began systemic corticosteroid treatment for aGVHD ≤72 hours prior to the start of
study drug dosing AND must receive 2 mg/kg/day methylprednisolone or equivalent on Day
1.

Exclusion Criteria:

1. Evidence of morphological relapsed, progressive, persistent, or untreated malignancy,
with the exception of nonmelanoma skin cancer and in situ ductal carcinoma of the
breast.

2. An unplanned donor lymphocyte infusion for persistent or recurrent malignancy after
HSCT.

3. Evidence of persistent molecular disease requiring treatment that was not specified
prior to HSCT.

4. Evidence of cGVHD or overlap syndrome

5. Use of immunosuppressants other than corticosteroids for the treatment of aGVHD.

6. Use of any systemic corticosteroids of >0.5 mg/kg/day methylprednisolone or equivalent
for any indication other than aGVHD within 7 days before the onset of aGVHD.