Recombinant EphB4-HSA Fusion Protein and Azacitidine or Decitabine for Relapsed or Refractory Myelodysplastic Syndrome, Chronic Myelomonocytic Leukemia, or Acute Myeloid Leukemia Patients Previously Treated With a Hypomethylating Agent

PRIMARY OBJECTIVES:

I. To describe the toxicities and assess the tolerability of recombinant EphB4-HSA fusion
protein (sEphB4-HSA) in combination with an approved hypomethylating agent (HMA) among
patients with myelodysplastic syndrome (MDS) who are refractory to or have lost their
response to one or more HMAs and among patients with relapsed/refractory acute myeloid
leukemia (AML) previously treated with a HMA.

SECONDARY OBJECTIVES:

I. To measure the expression of EphB4 among marrow and peripheral blood blasts in patients
with MDS & AML at baseline and over the course of treatment.

II. To measure the expression of immune check-point activating ligands (such as PD-L1, PD-L2)
on marrow and peripheral blood blasts in patients treated with HMA and sEphB4-HSA in
combination.

III. To profile immune subsets (activated and exhausted T cells, natural killer [NK] cells, T
regulatory cells, and myeloid derived suppressor cells) in the peripheral blood and marrow in
patients treated with HMA and sEphB4-HSA in combination.

IV. To assess efficacy of sEphB4-HSA in combination with an HMA as manifest by International
Working Group (IWG) response criteria, as well as time to development of acute myeloid
leukemia (AML) in patients with MDS and time to progression.

OUTLINE:

Patients receive recombinant EphB4-HSA fusion protein intravenously (IV) over 60 minutes on
days 1 and 15. Patients also receive azacitidine IV or subcutaneously (SC) on days 1-7 or
days 1-5 and 8-9, or decitabine IV on days 1-5. Administration of recombinant EphB4-HSA
fusion protein occurs before or after the HMA (not concurrently). Treatment repeats every 28
days for up to 12 courses in the absence of disease progression or unacceptable toxicity.

After completion of study treatment, patients are followed up every 6 months.

Inclusion Criteria:

- Adult subjects with advanced MDS requiring treatment with HMA and either refractory to
at least 4 cycles or progressing after previously documented response

- Patient must be treated within 6 months of the last HMA treatment and must be
willing to be treated with the same agent they last received on this study

- Prior treatment with novel HMA analog of decitabine on clinical trial is allowed;
in such cases, decitabine will be used as the standard of care agent

- MDS classified as intermediate 1-risk or high risk according to the international
prognostic scoring system (IPSS) or revised-IPSS

- Chronic myelomonocytic leukemia (CMML)

- Acute myeloblastic leukemia (AML) that was previously treated with HMA and is unfit
for intensive chemotherapy

- Patient must be within 6 months of prior treatment with HMA and must be willing
to be treated with the same agent on this study

- During the 8 weeks prior to inclusion in study, subjects must have a baseline bone
marrow examination including all of the following:

- Cytomorphology to confirm bone marrow blasts

- Cytogenetics

- Eastern Cooperative Oncology Group (ECOG) status 0-2

- Subject is able to understand and willing to comply with protocol requirements and
instructions

- Subject has signed and dated informed consent

- Total bilirubin (except for Gilbert's syndrome) =< 2.5 x upper limit of normal (ULN)

- Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) =< 3 x ULN

- Creatinine =< 2.5 x ULN

- Women of childbearing potential (WOCBP) and male patients with WOCBP as partners must
be using an adequate method of contraception to avoid pregnancy throughout the study
and for up to 12 weeks after the last dose of the investigational agent; subject is
practicing an acceptable method of contraception (documented in case report form
[CRF]); WOCBP include any female who has experienced menarche and who has not
undergone successful surgical sterilization (hysterectomy, bilateral tubal ligation,
or bilateral oophorectomy) or is not postmenopausal; post menopause is defined as:

- Amenorrhea >= 12 consecutive months without another cause or

- For women with irregular menstrual periods and on hormone replacement therapy (HRT), a
documented serum follicle stimulating hormone (FSH) level > 35 mIU/mL

- Women who are using oral contraceptives, other hormonal contraceptives (vagina
products, skin patches, or implanted or injectable products), or mechanical products
such as an intrauterine device or barrier methods (diaphragm, condoms, spermicides) to
prevent pregnancy, or are practicing abstinence or where their partner is sterile
(e.g., vasectomy) should be considered to be of childbearing potential

- WOCBP must have a negative serum test (minimum sensitivity 25 IU/L or equivalent units
of human chorionic gonadotropin [HCG]) within 72 hours prior to the start of
investigational product

- Patients with uncontrolled hypertension

Exclusion Criteria:

- Patients with AML whose white blood cell count exceeds 25,000

- Corrected QT (QTc) (Fridericia Correction Formula) > 480 on electrocardiogram (ECG)

- Patients whose electrolytes (sodium, potassium, calcium, magnesium) are abnormal or
cannot be normalized with standard intervention on the day of treatment with study
drug

- Patients who are actively receiving any other anticancer therapy

- Patients with a history of allergic reactions attributed to compounds of similar
chemical or biologic composition to HMAs

- Patients with a diagnosis of acute promyelocytic leukemia

- Patients with short life expectancy (less than 3 months) due to comorbidity other than
MDS

- Female subjects who are nursing or pregnant (positive serum or urine Beta-human
chorionic gonadotropin [B-hCG] pregnancy test)

- Patients with current alcohol or drug abuse

- Patients who have received treatment with an investigational drug within 30 days
preceding the first dose of study medication

- Patients with uncontrolled inter-current illness including, but not limited to,
ongoing or active infection, symptomatic congestive heart failure, unstable angina
pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would
limit compliance with study requirements

- Patients infected with hepatitis B, C or human immunodeficiency virus (HIV), unless
they are on stable and effective antiviral treatment

- Patients with a condition requiring systemic treatment with either corticosteroids (>
10 mg daily prednisone equivalent) or other immunosuppressive medications within 14
days of randomization; inhaled or topical steroids and adrenal replacement steroid
doses > 10mg daily prednisone equivalent, are permitted in the absence of uncontrolled
autoimmune disease

- MEDICATION-RELATED EXCLUSION CRITERIA

- Patients with uncontrolled hypertension (HTN) (> 160/90) will not be admitted onto the
study