Participants in the Phase II combination treatment arm could continue study treatment until PD developed, at which time they were to be discontinued. Participants in the single agent pomalidomide treatment arm who developed PD, confirmed by the IRAC, at any time had the option to receive oral dexamethasone in addition to their current dose of pomalidomide at the starting dose described above. Participants with PD who chose not to add dexamethasone to pomalidomide therapy were discontinued from study treatment. Participants who chose to add dexamethasone to pomalidomide therapy could continue study treatment until PD developed again, unacceptable toxicity or participant withdrew consent, at which point they were discontinued.