A Multicenter In-class Transition Study of Ixazomib Combined With Pomalidomide and Dexamethasone or With Lenalidomide and Dexamethasone in Adults With Relapsed/Refractory Multiple Myeloma

The main aim is to show that long-term use of ixazomib can improve symptoms of multiple myeloma and provide an effective long-term alternative treatment. Participants will take ixazomib orally (by mouth) with pomalidomide and dexamethasone or lenalidomide and dexamethasone in 28-day treatment cycles. Participants will be treated for a maximum of 39 cycles but may continue to receive ixazomib beyond 39 cycles if they are benefiting from it. A follow-up study visit will occur 30 days after the last dose of ixazomib. Participants will be monitored for up to 3 years.