Real-world clinical outcomes in patients with multiple myeloma treated with isatuximab after daratumumab treatment

Isatuximab and daratumumab are anti-CD38 monoclonal antibodies used to treat refractory multiple myeloma. Isatuximab is often used after unsuccessful daratumumab treatment; however, the clinical benefits of receiving isatuximab after daratumumab treatment have not been fully evaluated. Therefore, this retrospective cohort study assessed the clinical outcomes of 39 patients with multiple myeloma who were administered isatuximab after daratumumab. The median follow-up period was 8.7 months (range 0.1–25.0 months). The overall response rate was 46.2% (18 patients). The 1-year overall survival was 53.9%, with a median progression-free survival of 5.6 months. The median progression-free survival in patients with high and normal lactate dehydrogenase levels was 4.5 and 9.6 months, respectively ( P = 0.004). The median progression-free survival in patients with and without triple-class refractory disease was 5.1 months and not reached, respectively ( P = 0.001). The median overall survival in patients with high and normal lactate dehydrogenase levels was not reached and 9.3 months, respectively ( P = 0.001). The median overall survival in patients with and without triple-class refractory disease was 9.9 months and not reached, respectively ( P = 0.038). Our findings provide insight into the optimal use and timing of anti-CD38 antibody therapy.