[Impact of autologous hematopoietic stem cell transplantation on the efficacy of CAR-T treatment of relapsed/refractory multiple myeloma].

ABSTRACT

Objective: To evaluate the effect of autologous hematopoietic stem cell transplantation (ASCT) on the treatment of relapsed/refractory multiple myeloma (RRMM) with chimeric antigen receptor T cell (CAR-T) therapy. Methods: A retrospective cohort study. The clinical data of 168 patients with RRMM who underwent CAR-T therapy at the Department of Hematology, Xuzhou Medical University Hospital from 3 January 2020 to 13 September 2022 were analyzed. Patients were classified into a transplantation group (TG; n=47) and non-transplantation group (NTG; n=121) based on whether or not they had undergone ASCT previously. The objective response rate (ORR), progression-free survival (PFS), overall survival (OS) and the levels of CD3, CD4, CD8, CD19, CD56 and natural killer (NK) cells before CAR-T infusion were analyzed by χ2 test, Kaplan-Meier method and independent sample t-test. Results: Among 168 patients with RRMM, 98 (58.3%) were male. The median age of onset was 57 (range 30-70) years. After CAR-T therapy, the ORR of patients was 89.3% (92/103) in the NTG and 72.9% (27/73) in the TG. The ORR of the NTG was better than that of the TG (χ2=5.71, P=0.017). After 1 year of CAR-T therapy, the ORR of the NTG was 78.1% (75/96), and that of the TG was 59.4% (19/32). The ORR of the NTG was better than that of the TG (χ2=4.32, P=0.038). The median OS and PFS in the NTG were significantly longer than those in the TG (OS, 30 vs. 20 months; PFS, 26 vs. 12 months; both P<0.05). The CD4 level before CAR-T infusion in the TG was significantly lower than that in the NTG (25.65±13.56 vs. 32.64±17.21; t=-2.15, P=0.034), and there were no significant differences in the counts of CD3, CD8, CD19, CD56, and NK cells between the TG and NTG (all P>0.05). Conclusion: Among patients suffering from RRMM who received CAR-T therapy, patients who did not receive ASCT had significantly better outcomes than those who had received ASCT previously, which may have been related to the CD4 level before receiving CAR-T therapy.