# Final OS analyses from the TOURMALINE- MM3 and -MM4 RCTs of ixazomib maintenance in newly diagnosed multiple myeloma

## TL;DR

Two clinical trials found that ixazomib maintenance treatment did not significantly improve overall survival in newly diagnosed multiple myeloma patients compared to placebo.

## Contribution

The study provides final overall survival data from two phase 3 trials of ixazomib maintenance in multiple myeloma.

## Key findings

- Median OS was not reached in TOURMALINE-MM3 for either treatment arm.
- OS was 64.8 months with ixazomib and 69.5 months with placebo in TOURMALINE-MM4.
- No new safety signals were identified in either study.

## Abstract

TOURMALINE-MM3 (NCT02181413) and -MM4 (NCT02312258) were phase 3 studies of fixed-duration, single-agent ixazomib maintenance in post-transplant (TOURMALINE-MM3)/transplant-ineligible (TOURMALINE-MM4) patients with newly diagnosed multiple myeloma (NDMM) that demonstrated improved median progression-free survival (PFS) for ixazomib vs placebo. We present the final overall survival (OS) analyses for each study separately. In both studies, eligible patients were randomized 3:2 to receive ixazomib maintenance (3 mg [cycles 1–4], 4 mg [from cycle 5 if tolerated]) or matching placebo for ≤26 cycles, or until progressive disease/unacceptable toxicity. At median follow-up of approximately 8 years (TOURMALINE-MM3) and 5 years (TOURMALINE-MM4), median OS was not reached in either arm in MM3 (hazard ratio [HR], 1.025; 95% confidence interval [CI], 0.789–1.332; p = 0.850), and was 64.8 (ixazomib) vs 69.5 (placebo) months in MM4 (HR, 1.090; 95% CI, 0.861–1.381; p = 0.473). No new safety signals were identified in either study; incidence of new primary malignancies was low. Despite meeting their primary endpoints (PFS), neither final OS analysis of TOURMALINE-MM3/-MM4 showed statistically significant differences between fixed-duration ixazomib maintenance and placebo in patients with NDMM. The growing number of available, highly effective salvage treatments with novel mechanisms of action make demonstrating an OS advantage in front-line myeloma studies increasingly challenging.