Pomalidomide and Dexamethasone With or Without Ixazomib in Treating Patients With Relapsed Multiple Myeloma

This randomized phase I/II trial studies the side effects and best dose of pomalidomide and ixazomib when given together with dexamethasone and to see how well pomalidomide and dexamethasone with or without ixazomib works in treating patients with multiple myeloma that has come back. Biological therapies, such as pomalidomide and dexamethasone, may stimulate the immune system in different ways and stop cancer cells from growing. Ixazomib may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth. It is not yet known whether pomalidomide and dexamethasone are more effective with or without ixazomib in treating multiple myeloma.

PRIMARY OBJECTIVES: I. To establish the maximum tolerated dose (MTD) for combination therapy pomalidomide/dexamethasone/ixazomib. (Phase I) II. To assess whether the combination of pomalidomide/dexamethasone/ixazomib improves progression-free survival (PFS) relative to pomalidomide/dexamethasone. (Phase II) SECONDARY OBJECTIVES: I. To determine dose-limiting toxicities (DLTs). (Phase I) II. To analyze type and grade of all serious adverse events (SAEs). (Phase I) III. To analyze type and grade of all adverse events (AEs). (Phase I) IV. To analyze the reason for and incidence of dose modifications/omissions/delays. (Phase I) V. To assess preliminary evidence of clinical efficacy. (Phase I) VI. To assess whether the overall response rate (ORR), partial response (PR), very good partial response (VGPR), complete response (CR) or stringent CR (sCR) rate differ with respect to treatment regimen. (Phase II) VII. To assess the clinical benefit rate (CBR: minimal response \[MR\] + ORR) for pomalidomide/dexamethasone/ixazomib compared to pomalidomide/dexamethasone. (Phase II) VIII. To assess the disease control rate (DCR: stable disease \[SD\] + CBR) for pomalidomide/dexamethasone/ixazomib compared to pomalidomide/dexamethasone. (Phase II) IX. For those patients achieving a PR or better, we will assess whether the combination of pomalidomide/dexamethasone/ixazomib increases the duration of response (DOR) compared to pomalidomide/dexamethasone. (Phase II) X. To assess whether the combination of pomalidomide/dexamethasone/ixazomib improves overall survival (OS) compared to those taking pomalidomide/dexamethasone alone. (Phase II) XI. To assess time to next treatment (TNT) for patients taking pomalidomide/dexamethasone/ixazomib compared to those on pomalidomide/dexamethasone. (Phase II) XII. To evaluate the safety of pomalidomide/dexamethasone/ixazomib compared with pomalidomide/dexamethasone. (Phase II) XIII. For patients on the pomalidomide/dexamethasone arm who opt to cross-over to the pomalidomide/dexamethasone/ixazomib arm, assessment of response rate (ORR, CBR, DCR), DOR, TNT, PFS and OS will be evaluated from date of cross-over. (Phase II) XIV. To determine if baseline level of perceived fatigue and overall quality of life (QOL) is associated with OS. (Phase II) OUTLINE: This is a phase I, dose-escalation study of pomalidomide and ixazomib followed by a phase II study. After completion of study treatment, patients are followed up every 4 weeks until disease progression and then every 3 months for 3 years.