Japanese subgroup analysis of AQUILA trial: daratumumab vs active monitoring in high-risk smoldering multiple myeloma.

BACKGROUND: In the global phase 3 AQUILA trial, daratumumab monotherapy was associated with a significantly lower risk of progression to active multiple myeloma or death than active monitoring in patients with high-risk smoldering multiple myeloma without unexpected safety concerns (NCT03301220). METHODS: Here, we report a subgroup analysis of Japanese patients from the trial. Among the 28 Japanese patients, 15 and 13 patients received daratumumab and active monitoring, respectively. RESULTS: At the median follow-up of 60.9 months, the median progression-free survival was 59.1 and 24.8 months, respectively, with a hazard ratio of 0.25 [95% confidence interval (CI): 0.10-0.65] favoring daratumumab treatment. The overall response rate was 86.7% and 7.7%, with an odds ratio of 78.0 (95% CI: 6.24-974.71). Overall survival data were immature. Grade ≥3 adverse events were observed in five patients (33.3%) treated with daratumumab, which did not lead to treatment discontinuation, and no new safety concerns were noted. CONCLUSIONS: In this small-scale exploratory post hoc Japanese subgroup analysis, the efficacy of daratumumab monotherapy was generally comparable to that demonstrated in the global trial population, and no data suggesting new safety concerns were identified. These findings may provide useful information for determining treatment options in Japanese patients with high-risk smoldering multiple myeloma. Trial registration number: ClinicalTrials.gov number, NCT03301220.