MLN9708, also known as ixazomib citrate, is a prodrug of Ixazomib (MMLN-2238). MLN9708 is an orally bioavailable second generation proteasome inhibitor (PI) with potential antineoplastic activity. MLN9708, after hydrolyzing to pharmacologically active MLN2238 (ixazomib), is a next-generation proteasome inhibitor with demonstrated preclinical and clinical antimyeloma activity. MLN9708, compared with bortezomib, has improved pharmacokinetics, pharmacodynamics, and antitumor activity in preclinical studies.