A Study to Evaluate the Safety, Tolerability, PK, PD, and Clinical Activity of EQ001 in Subjects With aGVHD

The study will enroll approximately 84 subjects in two (2) parts:

Part A is an open label study and will enroll approximately 24 evaluable subjects with aGVHD
across 4 cohorts. The total number of patients will depend on the number of dose escalations
necessary to enable a decision to be made on the recommended dose to take forward into Part B
of the study. The planned dose escalation will start with cohort 1, where subjects will
receive EQ001 administered intravenously every two weeks for a total of 5 doses.

Part B is a randomized, double-blind, placebo-controlled study and will enroll approximately
60 additional subjects, randomized in a 2:1 ratio to either active treatment EQ001 (40) or
placebo (20). Subjects will receive either EQ001 or placebo administered intravenously every
two weeks for a total of 5 doses.

Inclusion Criteria:

1. Male or female subject at least 18 years of age for Part A, and at least 12 years of
age for Part B.

2. Recipients of allogeneic hematopoietic stem cell transplantation (alloHSCT) using
myeloablative or non myeloablative conditioning regimens.

3. Have a clinical diagnosis of acute GVHD requiring systemic immune suppressive therapy.

4. Deemed by the investigator to be likely to comply with the planned procedure as
required by the protocol for the duration of the study

Exclusion Criteria:

1. Presence of morphologic relapsed primary malignancy, treatment for relapse after
alloHSCT was performed, or requirement for rapid immunosuppressive treatment
withdrawal for early malignancy relapse.

2. Evidence of graft failure based on cytopenia(s), and as determined by the
investigator.

3. Evidence of post-transplant lymphoproliferative disease.

4. Any prior therapy for acute GVHD, except for alloHSCT prophylaxis regimens or
systemically administered corticosteroids.

5. As determined by the investigator, any medical, psychiatric, or other condition or
circumstance that is likely to negatively affect: the subject's participation in this
clinical study, the subject's safety, or the reliability of the study data.