An Open-Label Study to Evaluate the Efficacy and Safety of Two CDC-501 Dose Regimens When Used Alone or in Combination With Dexamethasone for the Treatment Relapsed or Refractory Multiple Myeloma

Inclusion Criteria

- Subject must be diagnosed with multiple myeloma (with measurable M-Protein in serum
and/or urine), and be considered to have disease progression after at least two
cycles of treatment or have relapsed after treatment.

- Subject must understand and voluntarily sign an informed consent document.

- Subject must not have received corticosteroids, other chemotherapy, thalidomide, or
other investigational agents, within 21 days of baseline

- ECOG (Zubrod) performance status of 0 to 2.

- Subject must be able to adhere to the study visit schedule and other protocol
requirements.

- Women of childbearing potential (WCBP ) must have a negative serum or urine pregnancy
test within 7 days of baseline. In addition, sexually active WCBP must agree to use
adequate contraceptive methods (oral, injectable, or implantable hormonal
contraceptive; tubal ligation; intra-uterine device; barrier contraceptive with
spermicide; or vasectomized partner) while on study drug.