There are two parts to this study:~Phase 1: To determine a safe dose of the medication cyclophosphamide in combination with pomalidomide and dexamethasone.~Phase 2: To see the difference in effectiveness of pomalidomide in combination with high dose dexamethasone with or without cyclophosphamide for the treatment of participants who have myeloma, which has relapsed to or become refractory (not responding) to prior treatment.
The main purpose of this study is to see whether pomalidomide can help people with myeloma. Researchers also want to find out if pomalidomide is safe and tolerable.