Question: Which type of myeloma is ixazomib being evaluated for?

Context:
Next generation proteasome inhibitors include carfilzomib and oprozomib which are irreversible epoxyketone proteasome inhibitors; and ixazomib and delanzomib which are reversible boronic acid proteasome inhibitors. Two proteasome inhibitors, bortezomib and carfilzomib are FDA approved drugs and ixazomib and oprozomib are in late stage clinical trials. 
The disease focus for all the proteasome inhibitors is multiple myeloma.
In addition, novel drug classes have shown promising activity in RR MM, including the orally-administered proteasome inhibitors ixazomib and oprozomib; monoclonal antibodies such as the anti-CS1 monoclonal antibody elotuzumab and anti-CD38 monoclonal antibody daratumumab; and histone deacetylase inhibitors such as panobinostat and rocilinostat.
These findings have informed the subsequent clinical development of ixazomib in multiple myeloma.
Phase 1 study of twice-weekly ixazomib, an oral proteasome inhibitor, in relapsed/refractory multiple myeloma patients.
An evidence-based review of ixazomib citrate and its potential in the treatment of newly diagnosed multiple myeloma.
Phase 1 study of weekly dosing with the investigational oral proteasome inhibitor ixazomib in relapsed/refractory multiple myeloma.
(18)F-FDG-PET/CT imaging in an IL-6- and MYC-driven mouse model of human multiple myeloma affords objective evaluation of plasma cell tumor progression and therapeutic response to the proteasome inhibitor ixazomib.
Sixty patients with relapsed and/or refractory multiple myeloma were enrolled on this phase 1 trial to evaluate safety and tolerability and determine the maximum tolerated dose (MTD) of single-agent, oral ixazomib given weekly for 3 of 4 weeks.
Sixty patients with relapsed and/or refractory multiple myeloma were enrolled on this phase 1 trial to evaluate safety and tolerability and determine the maximum tolerated dose (MTD) of single-agent, oral ixazomib given weekly for 3 of 4 weeks
Among second-generation proteasome inhibitors, ixazomib (MLN9708) is the first oral compound to be evaluated for the treatment of MM
Sixty patients with relapsed and/or refractory multiple myeloma were enrolled on this phase 1 trial to evaluate safety and tolerability and determine the maximum tolerated dose (MTD) of single-agent, oral ixazomib given weekly for 3 of 4 weeks. 
Ixazomib is the first investigational oral proteasome inhibitor to be studied clinically. In this phase 1 trial, 60 patients with relapsed/refractory multiple myeloma (median of 4 prior lines of therapy; bortezomib, lenalidomide, thalidomide, and carfilzomib/marizomib in 88%, 88%, 62%, and 5%, respectively) received single-agent ixazomib 0.24 to 2.23 mg/m(2) (days 1, 4, 8, 11; 21-day cycles). 
Safety and tolerability of ixazomib, an oral proteasome inhibitor, in combination with lenalidomide and dexamethasone in patients with previously untreated multiple myeloma: an open-label phase 1/2 study.
In a phase 1/2 trial we aimed to assess the safety, tolerability, and activity of ixazomib in combination with lenalidomide and dexamethasone in newly diagnosed multiple myeloma.METHODS: We enrolled patients newly diagnosed with multiple myeloma aged 18 years or older with measurable disease, Eastern Cooperative Oncology Group performance status 0-2, and no grade 2 or higher peripheral neuropathy, and treated them with oral ixazomib (days 1, 8, 15) plus lenalidomide 25 mg (days 1-21) and dexamethasone 40 mg (days 1, 8, 15, 22) for up to 12 28-day cycles, followed by maintenance therapy with ixazomib alone. 
Among second-generation proteasome inhibitors, ixazomib (MLN9708) is the first oral compound to be evaluated for the treatment of MM. Ixazomib has shown improved pharmacokinetic and pharmacodynamic parameters compared with bortezomib, in addition to similar efficacy in the control of myeloma growth and prevention of bone loss.
Among 55 response-evaluable patients, 15% achieved partial response or better (76% stable disease or better). These findings have informed the subsequent clinical development of ixazomib in multiple myeloma.
Ixazomib is an investigational, orally bioavailable 20S proteasome inhibitor. Sixty patients with relapsed and/or refractory multiple myeloma were enrolled on this phase 1 trial to evaluate safety and tolerability and determine the maximum tolerated dose (MTD) of single-agent, oral ixazomib given weekly for 3 of 4 weeks.

Answer: The disease focus for the  irreversible epoxyketone proteasome inhibitor ixazomib is multiple myeloma.
Exact answer: Multiple myeloma