A phase 2, open-label, multicenter study of ixazomib plus lenalidomide and dexamethasone in adult Japanese patients with relapsed and/or refractory multiple myeloma

BACKGROUND: TOURMALINE-MM1 was a global study that demonstrated a significant improvement in progression-free survival with ixazomib plus lenalidomide and dexamethasone compared with placebo plus lenalidomide and dexamethasone, in patients with relapsed and/or refractory multiple myeloma. The current study was conducted to evaluate further the efficacy and safety of ixazomib plus lenalidomide and dexamethasone in Japanese patients. METHODS: This phase 2, open-label, single-arm, multicenter study enrolled patients aged ≥ 20 years with relapsed and/or refractory multiple myeloma at 16 sites in Japan. Patients refractory to lenalidomide or proteasome inhibitor-based therapy at any line were excluded. The primary endpoint was the rate of very good partial response or better in the response-evaluable analysis set. Secondary endpoints were progression-free survival, overall response rate, duration of response, time to progression, overall survival and safety. RESULTS: In total, 34 patients were enrolled. The rate of very good partial response or better was 50.0% (95% confidence interval 31.9–68.1) and the overall response rate was 84.4% (95% confidence interval 67.2–94.7). Median progression-free survival was 22.0 months (95% confidence interval 17.3–not evaluable) and median overall survival was not estimable. The safety profile of ixazomib plus lenalidomide and dexamethasone in this study was similar to that in the TOURMALINE-MM1 study. CONCLUSIONS: The efficacy and safety of ixazomib plus lenalidomide and dexamethasone in Japanese patients with relapsed and/or refractory multiple myeloma are comparable with reported TOURMALINE-MM1 study results. CLINICALTRIALS.GOV IDENTIFIER: NCT02917941; date of registration September 28, 2016. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10147-021-02030-7.