A Safety and Tolerability Study of CDX-301 With or Without Plerixafor for Stem Cell Mobilization in Matched Related Allogeneic Donor/Recipient Sibling Transplant Pairs

Inclusion Criteria:

Donors:

- Read, understood and provided written informed consent and willing to comply with all
study requirements and procedures

- 6 out of 6 HLA-matched sibling

- Negative test for human immunodeficiency virus (HIV), hepatitis B, and hepatitis C

- Both male and female patients of childbearing potential enrolled in this trial must
use adequate birth control measures

- Subjects should be in generally good health and without significant medical
conditions, based upon pre-study medical history, physical examination,
electrocardiogram (ECG), chest X- ray, and laboratory tests

- Meets all criteria to serve as a mobilized blood cell donor in accordance with all
applicable individual Transplant Center criteria

Recipient:

- Read, understood and provided written informed consent and willing to comply with all
study requirements and procedures

- 6 out of 6 HLA-matched sibling

- Both male and female patients of childbearing potential enrolled in this trial must
use adequate birth control measures

Diagnosis of one of following:

- Acute Myelogenous Leukemia (AML) in 1st remission or beyond

- Acute Lymphoblastic Leukemia (ALL) in 1st remission or beyond

- Chronic Myelogenous Leukemia (CML)

- Chronic Lymphoblastic Leukemia (CLL), relapsing after at least one prior regimen

- Myelodysplastic Syndrome (MDS), either intermediate 1,2, or high risk by IPI Scoring
System or transfusion dependent

- Non-Hodgkins Lymphoma (NHL) or Hodgkins Disease (HD) in 2nd or greater complete
remission, partial remission, or in relapse

- Meets all criteria to serve as a transplant recipient in accordance with all
applicable individual Transplant Center criteria

Exclusion Criteria:

Donors:

- Unwilling or unable to give informed consent, or unable to comply with the protocol
including required follow-up and testing

- Prior treatment with any rhuFlt3L product

- Any vaccination within 4 weeks prior to CDX-301 dosing

- Donation of blood within 8 weeks, or donation of plasma within 2 weeks prior to
CDX-301 dosing

- Any experimental treatment within 4 weeks prior to CDX-301 dosing

- Use of systemic immunosuppressive agents (excluding topical steroids) within 12
months prior to CDX-301 dosing.

- History of first degree relatives with primary or secondary immunodeficiency to
include type 1 diabetes, multiple sclerosis, rheumatoid arthritis, scleroderma or
psoriasis

- History of tuberculosis infection

- Herpes zoster within 3 months prior to starting study drug

- Pregnant or nursing

Recipient:

- Unwilling or unable to give informed consent, or unable to comply with the protocol
including required follow-up and testing

- Prior allogeneic transplant

- More than one prior autologous transplant

- Prior treatment with any rhuFlt3L product

- Any vaccination within 4 weeks prior to transplant

- Uncontrolled infection at the time of the transplant conditioning regimen

- Pregnant or nursing

- Any condition, which, in the opinion of the clinical investigator, would interfere
with the evaluation of the study outcome