The drug being tested in this study is called ixazomib. This study will evaluate the tolerability, safety, and PK of ixazomib administered alone or in combination with lenalidomide and dexamethasone in participants with relapsed and/or refractory multiple myeloma.~This study will enroll approximately 24 participants (3 to 6 participants in each dose-escalation cohort). Participants will be assigned to receive treatment in one of the four treatment cohorts:~Cohort 1: Ixazomib 4.0 mg~Cohort 2: Ixazomib 4.0 mg + Lenalidomide and Dexamethasone~Cohort 3: Ixazomib 5.5 mg~Cohort 4: Ixazomib 5.5 mg + Lenalidomide and Dexamethasone~This multi-center trial will be conducted in Japan. The overall time to participate in this study is approximately 7 years. Participants will make a final visit 29 days after receiving their last dose of drug for a follow-up assessment.
The purpose of this study is to evaluate the tolerability, safety, pharmacokinetics (PK) of ixazomib alone or in combination with lenalidomide and dexamethasone (Rd), and antitumor activity of ixazomib in participants with RRMM.