Study Evaluating the Safety and Tolerability of Weekly Dosing of Oral IXAZOMIB in Adult Patients With Relapsed and Refractory Multiple Myeloma

The drug being tested in this study is called ixazomib citrate (MLN9708). Ixazomib citrate is being tested for people who have multiple myeloma who have relapsed after treatment or become unresponsive to treatment. This study will determine the maximum tolerated dose (MTD) of ixazomib citrate using a dose escalation scheme. Once MTD is established, participants will be enrolled at MTD into one of the 4 expansion cohorts to characterize the safety, tolerability and efficacy of MLN9708. Blood samples for safety labs, hematology, serum chemistry and pharmacokinetic evaluations will be obtained at the timepoints specified. Disease response assessment is to be performed on the first day of every other cycle beginning with Cycle 3. The study will enroll approximately 60 patients. All participants will receive treatment with ixazomib citrate. This multi-center trial will be conducted in the United States. The overall time to participate in this study is up to 60 days, and participants will make 12-16 visits to the clinic for study procedures.