OBJECTIVES: The shifting paradigm in NDMM pSCT toward continuous therapy to delay progression must be balanced against its impact on HRU. Ixazomib uniquely meets the ideal attributes of MT – efficacy, convenient oral administration and dosing, and tolerable toxicity – to minimize HRU burden. To compare HRU for ixazomib vs placebo MT in TOURMALINE-MM3.

METHODS: Patients from 167 institutions in 30 countries were randomized in a 3:2 ratio to MT with oral ixazomib or placebo on days 1, 8, and 15 in 28-day cycles for 2 years pSCT. HRU was collected every 4 weeks up to first progression and every 12 weeks thereafter. In each arm, mean inpatient length of stay (LOS) and rates per total patient-years from start of protocol MT to end of follow-up were estimated for inpatient, intensive care unit [ICU], emergency department [ED] and non-protocol directed outpatient medical encounters.

RESULTS: Among patients randomly assigned to ixazomib (n=395) or placebo (n=261) MT, the baseline characteristics between arms were well balanced – overall median age: 58; ECOG performance status 0-1: 97%; at least very good partial response prior to MT: 79%. At median follow-up (31 months), HRU rates per patient-year were similar between ixazomib and placebo (inpatient: 0.42 [95% CI: 0.36, 0.47] vs 0.36 [95% CI: 0.30, 0.42]; ICU: 0.02 [95% CI: 0.01, 0.03] vs 0.02 [95% CI: 0.00, 0.03]; outpatient: 5.37 [95% CI: 5.19, 5.55] vs 5.18 [95% CI: 4.95, 5.40]) with the exception of ED: 0.17 [95% CI: 0.14, 0.20] vs 0.08 [95% CI: 0.06, 0.11]. The inpatient/ICU mean LOS (days) were similar between ixazomib and placebo (6.2 [95% CI: 4.7, 7.7] vs 5.1 [95% CI: 3.4, 6.8]/0.4 [95% CI: 0.1, 0.7] vs 0.6 [95% CI: 0.0, 1.2]).

CONCLUSIONS: With the exception of ED admissions, HRU burden with ixazomib MT is comparable to placebo.