PB2137: INFLUENCE OF PREVIOUS RADIOTHERAPY ON THE EFFECT OF CART CELL THERAPY IN AGGRESSIVE B-CELL LYMPHOMA

Abstract

Background: In previous studies, radiotherapy has an effect on the number and function of lymphocytes. In recent years, with the advent of CART cell therapy, the PFS and OS of relapsed and refractory highly aggressive B-cell lymphoma have been significantly improved. Whether previous radiotherapy is effective for CART cell therapy The impact is inconclusive. Aims: To investigate the influence of the radiotherapy history before CART cell therapy on the culture, expansion and treatment effect of CART cells in patients with aggressive B-cell lymphoma. Methods: A retrospective study from December 2018 to September 2021 in adult patients with aggressive B-cell lymphoma treated with CART cells at our center who underwent radiotherapy before lymphocyte collection. The patient’s previous radiotherapy dose, radiotherapy distance from lymphocyte collection time, peripheral blood lymphocyte count before lymphocyte collection, CART cell culture dose, reinfusion dose, and curative effect statistics of 3 months after CART cell reinfusion were counted. Statistical methods such as logistic regression and spearman correlation analysis were used for analysis. Results: 16 males and 18 females were eligible, with a median age of 45.5 years (18-86 years). These included 2 Burkitt lymphoma, 26 unspecified diffuse large B-cell lymphoma, 5 primary mediastinal B-cell lymphoma, and 1 primary central lymphoma. The median time from lymphocyte collection to previous radiotherapy was 151 (5-4772) days, and the median radiation dose was 46 (4-66) Gy. The absolute value of lymphocytes before the collection of lymphocytes was 0.79 (0.14-2.58)×10^9/L, which was lower than the normal reference value. The median culture dose of CART cells was 0.837(0.1-7.03)×10^6/kg, and the median infusion dose was 0.837(0.1-4.2)×10^6/kg. After CART cell infusion, the peak CART cell expansion was 18.6(0-919)×10^6/kg, 3-month CR: 20.59%, 3-month ORR: 44.12%. The time interval between previous radiotherapy and lymphocyte collection had a significant effect on 3-month CR, P=0.0417. The effect on 3-month ORR was not statistically significant, P=0.1388. There was no significant effect of previous radiotherapy dose on CR/ORR at 3 months, with P values ​​of 0.9188/0.5078, respectively. The effect of previous radiotherapy dose on the CART cell culture dose and the maximum value of CART cell expansion was not found to be statistically significant. CR and ORR at 3 months after reinfusion were significantly correlated with the reinfusion dose, with P values ​​of 0.0102 & 0.0121, respectively. There was no significant relationship between the absolute value of lymphocytes and the proportion of lymphocytes, the culture dose and the CR/ORR of the curative effect. Summary/Conclusion: Radiotherapy affects the number and cell quality of lymphocytes, the median culture dose is significantly lower than the 2×10^6/kg reported in the literature. In patients with aggressive B-cell lymphoma who had a history of radiotherapy, the CR/ORR at 3 months after CART cell therapy was significantly lower than that reported. This adverse effect was independent of radiation dose. The CR rate is affected by the time interval between radiotherapy and lymphocyte collection. The longer the interval, the greater the adverse effect.