PRIMARY OBJECTIVES:
I. To determine the confirmed overall response rate (>= partial response [PR]) of ixazomib [ixazomib citrate], used as a single agent in patients with relapsed multiple myeloma, who are proteasome inhibitor naive (including bortezomib) naive OR have received less than 6 cycles of therapy with bortezomib and had a better than PR with no progression at the time of discontinuation. (Arm A - Permanently closed to accrual as of Addendum 5) II. To determine the confirmed overall response rate (>= PR) of ixazomib at a 4 mg dose level in combination with dexamethasone in patients with relapsed multiple myeloma, who are proteasome inhibitor naive (including bortezomib) naive OR have received less than 6 cycles of therapy with bortezomib and had a better than PR with no progression at the time of discontinuation. (Arm B) III. To determine the confirmed overall response rate (>= PR) of ixazomib at a 5.5 mg dose level in combination with dexamethasone in patients with relapsed multiple myeloma, who are proteasome inhibitor naive (including bortezomib) naive OR have received less than 6 cycles of therapy with bortezomib and had a better than PR with no progression at the time of discontinuation. (Arm C) IV. To determine the confirmed overall response rate (>= PR) of ixazomib in combination with cyclophosphamide and dexamethasone in patients with relapsed multiple myeloma, who are proteasome inhibitor naive (including bortezomib) naive OR have received less than 6 cycles of therapy with bortezomib and had a better than PR with no progression at the time of discontinuation. (Arm D) V. To determine the confirmed overall response rate (>= PR) of ixazomib in combination with cyclophosphamide, daratumumab, and dexamethasone in patients with relapsed multiple myeloma. (Arm E)
SECONDARY OBJECTIVES:
I. To determine the overall response rate of ixazomib in combination with dexamethasone, when dexamethasone is added to ixazomib for lack of response or for progression. (Arm A) II. To determine the event free survival and overall survival among patients with relapsed myeloma following treatment with ixazomib with dexamethasone added for lack of response or progression. (Arm A) III. To determine the event free survival and overall survival among patients with relapsed myeloma following treatment with ixazomib at two different doses, in combination with dexamethasone. (Arms B and C) IV. To determine the event free survival and overall survival among patients with relapsed myeloma following treatment with ixazomib in combination with cyclophosphamide and dexamethasone. (Arm D) V. To determine the event free survival and overall survival among patients with relapsed myeloma following treatment with ixazomib in combination with cyclophosphamide, daratumumab, and dexamethasone. (Arm E)
OUTLINE: Patients are randomized to 1 of 4 treatment arms (Arm A permanently closed to accrual as of Addendum 5).
ARM A: Patients receive ixazomib citrate orally (PO) on days 1, 8, and 15. Patients with lack of minor response by the end of the second cycle or lack of partial response by the end of the fourth cycle also receive dexamethasone PO on days 1, 2, 8, 9, 15, and 16. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity.
ARM B: Patients receive ixazomib citrate PO on days 1, 8, and 15 and dexamethasone PO on days 1, 8, and 15. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity.
ARM C: Patients receive higher dose of ixazomib citrate PO on days 1, 8, and 15 and dexamethasone PO on days 1, 8, and 15. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity.
ARM D: Patients receive ixazomib citrate PO on days 1, 8, and 15 and cyclophosphamide PO (cycles 1-18 only) and dexamethasone PO on days 1, 8, 15, and 22. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity.
ARM E: Patients receive ixazomib citrate PO on days 1, 8, and 15, cyclophosphamide PO (cycles 1-12 only) on days 1, 8, 15, 22, and daratumumab intravenously (IV) on days 1, 8, 15, 22 (cycles 1-2), days 1 and 15 (cycles 3-6), and day 1 in all subsequent cycles. Patients also receive dexamethasone IV or PO on days 1, 8, 15, and 22. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity.
After completion of study treatment, patients are followed up every 6 or 12 months for 2 years.