Inclusion Criteria:

- Histologically/cytologically confirmed diagnosis of:

- Multiple myeloma (MM)

- Chronic Lymphocytic Leukemia (CLL) / Small Lymphocytic Lymphoma (SLL)

- Mantle Cell Lymphoma (MCL)

- Chronic Myelogenous Leukemia (CML)

- Refractory to/relapsed after and/or intolerant of one or more standard therapies or
for which no standard therapy exists.

- ECOG performance status 0-2.

- Adequate bone marrow, cardiovascular, renal and hepatic function

- Recovery from all adverse events due to prior therapies

- Contraception

Exclusion Criteria:

- Prior chemotherapy, monoclonal antibodies, investigational agents, or radiation
therapy (involving ≥ 30% of the active bone marrow) within 14 days prior to the first
dose (note nitrosoureas and mitomycin are not permitted for at least 42 days before
the first dose of RGB-286638).

- CNS involvement of the hematological malignancy.

- Active or unstable cardiac disease and/or history of myocardial infarction within 6
months and/or history of clinically significant ventricular arrhythmias.

- Concomitant therapies that are known to prolong the QT interval and are associated
with a risk of Torsades de Pointes (TdP) are not permitted within 7 days before the
first dose; however, amiodarone is not permitted within 90 days before the first
dose.

- Patients with uncontrolled and unstable intercurrent illness.

- Concomitant therapy with inhibitors and/or inducers of CYP450 3A4 within 1 week of
the first dose.

- Bleeding disorder unrelated to hematological malignant disease.

- HIV or HIV-related malignancy.

- History of other malignancies except: (i) adequately treated basal or squamous cell
carcinoma of the skin; (ii) curatively treated, a) in situ carcinoma of the uterine
cervix, b) prostate cancer, or c) superficial bladder cancer; or (iii) other
curatively treated solid tumor with no evidence of disease for ≥ 2 years.

- Any other condition that would, in the investigator's judgment, contraindicate the
patient's participation in the clinical study due to safety concerns or compliance
with clinical study procedures.