Randomized subjects will receive CC-5013 plus high-dose dexamethasone or placebo appearing identical to CC-5013 plus high-dose dexamethasone in 4-week cycles. Each subject will participate in a treatment phase and a follow-up phase.

This was a phase 3, multicenter, double-blind, placebo-controlled, parallel-group study of the efficacy and safety of CC-5013 plus oral pulse high-dose dexamethasone and oral pulse high-dose dexamethasone therapy alone in subjects with relapsed or refractory multiple myeloma. Eligible subjects were randomized in a 1:1 ratio to 1 of 2 treatment groups: Subjects in the CC-5013/Dex treatment group took 25 mg of CC-5013 orally once daily on Days 1 to 21 and a matching placebo capsule once daily on Days 22 to 28 of each 28-day cycle; Subjects in the Placebo/Dex treatment group took 1 placebo capsule on Days 1 to 28 of each 28-day cycle. Subjects in both treatment groups took 40 mg of dexamethasone orally once daily on Days 1 to 4, 9 to 12, and 17 to 20 of each 28-day cycle for the first 4 cycles of therapy. Beginning with Cycle 5, the dose of dexamethasone was reduced to 40 mg orally once daily on Days 1 to 4 for the remaining cycles.

Inclusion Criteria:

• Prior or current diagnosis Durie-Salmon stage II or III multiple myeloma.
• No more than 3 previous anti-myeloma regimens
• No high-dose dexamethasone (total monthly dose of dexamethasone greater than 200 mg) within 6 months of study randomization.
• Measurable levels of myeloma paraprotein in serum or urine (24-hour collection sample).

Exclusion Criteria:

• Prior development of disease progression during high-dose dexamethasone containing therapy.
• Laboratory abnormalities: Absolute neutrophil count less than 1,000 cells/mm cubed
• Laboratory abnormalities: Platelet count less than 75,000/mm cubed
• Laboratory abnormalities: Serum creatinine greater than 2.5 mg/dL
• Laboratory abnormalities: Serum glutamic oxaloacetic transaminase (SGOT, aspartate transaminase [AST]) or serum glutamic pyruvic transaminase (SGPT, alanine transaminase [ALT])greater than 3.0 x upper limit of normal
• Laboratory abnormalities: Serum total bilirubin greater than 2.0 mg/dL
• Prior history of malignancies other than multiple myeloma unless the subject has been free of the disease for greater than or equal to 5 years.
• Known hypersensitivity to thalidomide or dexamethasone.
• Development of a desquamating rash while taking thalidomide.