This Phase 1 study of oral CX-4945 is designed to test the safety, tolerability, and highest safe dose level of this CK2 inhibitor in patients with relapsed or refractory multiple myeloma.

Elevated CK2 activity has been associated with malignant transformation and aggressive tumor growth. Over expression of CK2 has been documented in multiple types of cancers, including multiple myeloma, and inhibition of CK2 represents a potential therapeutic strategy to target a specific molecular defect perpetuating many cancers. CX-4945 has demonstrated potent inhibition of CK2 enzymatic activity. This study will evaluate the safety, pharmacokinetics, and pharmacodynamic effects of CX-4945 when administered to patients with multiple myeloma.

Inclusion Criteria:

• Males or females at least 18 years of age
• Confirmed relapsed or refractory multiple myeloma after at least two prior lines of therapy.
• Measureable disease.
• Karnofsky Performance Status at least 60%
• Adequate liver and renal function and hematology laboratory values
• Female patients of child-bearing potential must have a negative pregnancy test.
• Signed informed consent.

Exclusion Criteria:

• Treatment with systemic cancer therapy within 21 days before screening.
• Major surgery within 4 weeks or minor surgery within 2 weeks of the start of study drug.
• Grade 3 sensory neuropathy or motor neuropathy with pain
• Concurrent severe or uncontrolled medical disease.
• Active systemic fungal, bacterial, and/or viral infection.
• Difficulty with swallowing, or an active malabsorption syndrome.
• Gastrointestinal diseases including Crohn's disease or hemorrhagic coloproctitis.
• History of gastric or small bowel surgery.
• Pregnant or nursing females.