Safety Evaluation of Intramuscular Injections of PLX-R18 in Subjects With Incomplete Hematopoietic Recovery Following Hematopoietic Cell Transplantation

Inclusion Criteria:

1. Age ≥18 years.

2. At least 4 months after HCT, either autologous or allogeneic (of any source, with any
preparatory regimen, for any indication), prior to study treatment.

3. Sustained platelet count ≤50,000/µL, and/or sustained Hgb ≤8 g/dL and/or sustained ANC
≤1000/mm3, which is considered by the Investigator as related to the nature of the
graft (higher transient levels following occasional blood product transfusions are
allowed).

4. Stable donor cell chimerism in at least 3 consecutive tests prior to treatment.

5. If the subject had allogeneic HCT for a malignant disease, the subject should have
complete donor chimerism. (*complete donor chimerism determined by the investigator
per site's standards)

6. General performance status evaluated by ECOG 0-2 scale.

Exclusion Criteria:

1. Evidence of active malignancy at the time of HCT or at any time since the HCT.

2. No other known etiology of the thrombocytopenia (such as infection, medication, etc.)
or anemia (such as blood loss, iron deficiency, etc.).

3. Current active infection requiring systemic treatment.

4. Acute graft versus host disease (GvHD) Grade III or IV, or severe chronic GvHD.

5. History of malignancy (other than the disease that required the HCT) within 5 years
prior to screening.

6. History of severe allergic/hypersensitivity reaction or significant transfusion
reaction.

7. Severe or uncontrolled/unstable cardiac, pulmonary, hepatic or renal disease,
including MI or CVA within 3 months prior to treatment.