Absolute lymphocyte count prior lymphodepletion impacts outcomes in multiple myeloma patients treated with CAR-T cells.
BACKGROUND
Chimeric antigen receptor (CAR)-T cell therapy has shown unprecedented response rates in patients with relapsed/refractory (R/R) multiple myeloma (MM). However, the factors associated with immediate response and durable remission have not been fully elucidated.


OBJECTIVE
This study aimed to investigate the impact of pre-lymphodepletion (pre-LD) absolute lymphocyte count (ALC) on the outcomes of CAR-T cell therapy and cytokine release syndrome (CRS).


STUDY DESIGN
A receiver operating characteristic curve was used to determine the optimal cutoff value of pre-LD ALC. The correlation of pre-LD ALC with deep response (defined as very good partial response or better), CRS, and long-term outcomes was analyzed in 85 patients with R/R MM who received CAR-T cell treatment.


RESULTS
The median pre-LD ALC was 1.0 × 109/L (range, 0.1-2.9). The optimal cutoff value of pre-LD ALC was 0.75 × 109/L. Twenty-two (26%) patients had a low pre-LD ALC (< 0.75 × 109/L) and 63 patients (74%) had a high pre-LD ALC (≥ 0.75 × 109/L). The deep response rate was significantly higher in patients with a high pre-LD ALC compared with that in patients with a low pre-LD ALC (76% vs. 41%, P = 0.002). Patients with a low pre-LD ALC had significantly inferior overall survival (OS) and progression-free survival (PFS) compared with those with a high pre-LD ALC (median OS, 15.4 months vs. not reached, P < 0.001; median PFS, 8.4 months vs. 27.3 months, P < 0.001). No correlation between pre-LD ALC and CRS was observed.


CONCLUSION
In conclusion, pre-LD ALC could be a useful indicator to predict the outcomes of CAR-T cell therapy in patients with R/R MM.
['Liu|Yang|Y|', 'Chen|Wei|W|', 'Yu|Mingxiao|M|', 'Li|Hujun|H|', 'Cheng|Hai|H|', 'Cao|Jiang|J|', 'Yan|Zhiling|Z|', 'Shi|Ming|M|', 'Zhu|Feng|F|', 'Sun|Haiying|H|', 'Sang|Wei|W|', 'Li|Depeng|D|', 'Wu|Qingyun|Q|', 'Chen|Chong|C|', 'Zheng|Junnian|J|', 'Xu|Kailin|K|', 'Li|Zhenyu|Z|']
absolute lymphocyte count multiple myeloma Chimeric antigen receptor T cell