Investigation of the risk factors to predict cytokine release syndrome in relapsed or refractory B-cell acute lymphoblastic leukemia patients receiving IL-6 knocking down anti-CD19 chimeric antigen receptor T-cell therapy

Abstract

CD19 chimeric antigen receptor-T (CAR-T) cell therapy has achieved remarkable results in patients with relapsed or refractory B-cell acute lymphoblastic leukemia (r/r B-ALL). However, the cytokine release syndrome (CRS) was presented in most patients as common toxicity and severe CRS (sCRS) characterized by the sharp increase in interleukin-6 (IL-6) could be life-threatening. We conducted a phase II clinical trial of ssCAR-T-19 cells, anti-CD19 CAR-T cells with shRNA targeting IL-6, in 61 patients with r/r B-ALL. This trial was registered at www.clinicaltrials.gov as #NCT03275493. Fifty-two patients achieved CR while nine patients were considered NR. The median duration of response (DOR) and overall survival (OS) were not reached (>50 months). CRS developed in 81.97% of patients, including 54.10% with grades 1 to 2 (grade 1, 31.15%; grade 2, 22.95%) and 27.87% with grades 3 to 4 (grade 3, 26.23%; grade 4, 1.64%). sCRS occurs earlier than mild CRS (mCRS). A multivariable analysis of baseline characteristics identified high bone marrow disease burden and poor genetic risk before infusion as independent risk factors for sCRS. After infusion, patients with sCRS exhibited larger expansion of ssCAR-T-19 cells, higher peak levels of IL-6, IL-10, and IFN-γ, and suffered more severe hematological and non-hematological toxicities compared with those with mCRS.

Keywords: IL-6 knocking down; chimeric antigen receptor T-cell therapy; cytokine release syndrome; relapsed or refractory B-cell acute lymphoblastic leukemia; risk factors.

Conflict of interest statement

Authors M-HLi, L-QKang, and LYu were employed by the Shanghai Unicar-Therapy Bio-Medicine Technology Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Copyright © 2022 Gong, Qiu, Li, Chen, Li, Yu, Kang, Sun, Wu, Yu and Xue.

Figures

Figure 1

Duration of response and overall survival. (A) Kaplan–Meier estimates of the duration of response (DOR) in patients who achieve CR after ssCAR-T-19 infusion with censoring patients at subsequent allogeneic stem-cell transplant. (B) Kaplan–Meier estimate of overall survival (OS) in all the patients without censoring of patients at subsequent allogeneic stem-cell transplant. Median DOR in patients who achieved CR and median OS in all the patients were not reached. Dashed lines in (A) and (B) denote the 95% confidence interval.

Figure 2

Analysis of patient characteristics associated with the severity of CRS. (A, B) Comparison of bone marrow disease burden or MRD between patients with mCRS and sCRS. All the patients were evaluated for bone marrow disease burden and MRD before ssCAR-T-19 cell infusion. Mean values were calculated for each group. P-values were calculated using Mann–Whitney U test. **means p <0.01, *p-values <0.05. (C, D) The test for linear trend between bone marrow disease burden or MRD and the severity of CRS. Bone marrow disease burden and MRD were divided into four groups and the CRS were graded into five levels. The size of the circle represented the number of patients. Mantel–Haenszel chi-square test was used to calculate the linear trend.

Figure 3

The ROC curve for the two-variable regression model. Sixty-one r/r B-ALL patients receiving ssCAR-T-19 therapy were enrolled in the forward-selected logistic regression model. The model was used to predict which patients would develop sCRS after ssCAR-T-19 cell infusion. The logit(p) function transformed the logistic regression score into the predicted probability of the case model. Logit (p) = ln (p/1 − p). The ROC curve was drawn using the logistic regression score. The severity of CRS was predicted using bone marrow disease burden and genetic risk of patients with r/r B-ALL before ssCAR-T-19 infusion. The sensitivity was 70.6%, the specificity was 86.4%, and AUC was 0.785.

Figure 4

Peak cytokines, CRP, ferritin after ssCAR-T-19 infusion. (A–C) Levels of peak cytokines, CRP and ferritin of the patients after ssCAR-T-19 infusion. P-values were calculated using t-test. ****means p-values <0.0001, ***p <0.001, and **p <0.01. (A) IL6, IL10, and IFN-γ, (B) CRP and, (C) ferritin are shown in patients with mCRS and sCRS, respectively. The error bars in (A–C) represent mean ± SD.

Figure 5

Hematologic and non-hematologic toxicities after ssCAR-T-19 infusion. (A–G) Hematologic and non-hematologic toxicities after ssCAR-T-19 infusion. P-values were calculated using t-test. ****means p-values <0.0001, ***p <0.001, **p <0.01, and *p <0.05. (A) Minimum absolute neutrophil count, (B) hemoglobin (Hb) and platelet count (PLT), (C) maximum PT and APTT, (D) minimum fibrinogen (FIB), (E) maximum total bilirubin (TB), serum aspartate aminotransferase (AST), and gamma-glutamyl transpeptidase (GGT), (F) creatinine (Cr), and (G) N-terminal pro-brain natriuretic peptide (NT-proBNP) is shown in patients with mCRS and sCRS, respectively. The upper and lower boundaries of each box indicate the 25th and 75th percentiles. The middle horizontal lines represent the median values and the whiskers mean the minimum and maximum.

Figure 6

Expansion and persistence of ssCAR-T-19 cell in peripheral blood. The copies of ssCAR-T-19 cells in peripheral blood measured by qRT-PCR after infusion. Forty-eight patients with complete expansion data were included. Patients who achieved CR were shown in black while patients who achieved NR were shown in red.

Figure 7

Relationship between peak copies of ssCAR-T-19 cell, bone marrow disease burden and CRS grade in r/r B-LL patients. (A) Comparison of ssCAR-T-19 cell expansion between patients with mCRS and sCRS. Mean values were calculated for each group. P-value was calculated using a Mann–Whitney U test. **means p-value <0.01. (B) Relationship between peak copies of ssCAR-T-19 cell, bone marrow disease burden, and CRS grade in r/r B-ALL patients. The bone marrow disease burden was divided into four groups. The y-axis represented the peak copies of the ssCAR-T-19 cells within 14 days after infusion. Mean values were calculated for each group and error bars indicate standard deviation. The different shapes of icons represented the grade of CRS. Red represented patients who achieved CR while blue represented patients who had no remission.