Prophylactic Tocilizumab Prior to Anti-CD19 CAR-T Cell Therapy for Non-Hodgkin Lymphoma

Abstract

Anti-CD19 chimeric antigen receptor T (CAR-T) cells have demonstrated activity against relapsed/refractory lymphomas. Cytokine release syndrome (CRS) and immune effector cell - associated neurotoxicity syndrome (ICANS) are well-known complications. Tocilizumab, a monoclonal antibody targeting the interleukin-6 (IL-6) receptor was administered 1 hour prior to infusion of anti-CD19 CAR-T cells with CD3ζ/4-1BB costimulatory signaling used to treat non-Hodgkin lymphoma patients. Relapsed/refractory lymphoma patients treated with anti-CD19 CAR-T cells were included in this analysis. Cytokine plasma levels were measured by electrochemiluminescence before lymphodepleting chemotherapy, prior to infusion and then on days 2, 4,6, and 14 days after treatment. Twenty patients were treated. Cell products included locally manufactured anti-CD19 CAR-T (n=18) and tisagenlecleucel (n=2). There were no adverse events attributed to tocilizumab. Ten patients had grade 1-2 CRS at a median of 4 (range 3-7) days. There were no cases of grade ≥3 CRS. Five patients had ICANS, grade 1 (n=4) and grade 4 (n=1). Laboratory studies obtained prior to lymphodepleting chemotherapy were comparable between patients with and without CRS, except for interleukin (IL)-15 plasma concentrations. patients with CRS had higher post-infusion ferritin and C reactive protein, with more marked increases in inflammatory cytokines, including IL-6, IL-15, IFN-γ, fractalkine and MCP-1. Fifteen patients (75%) achieved CR and 2 (10%), PR. One-year OS and PFS estimates were 83% and 73%. Prophylactic tocilizumab was associated with low CRS incidence and severity. There were no adverse events associated with tocilizumab, no increase in frequency or severity of ICANS and excellent disease control and overall survival.

Keywords: CAR- T cells; cytokine release syndrome (CRS); lymphoma; prophylaxis; tocilizumab.

Figure 1

Laboratory parameters, tumor burden and CAR-T cell expansion. (A) Baseline laboratory parameters (n = 20): clockwise: absolute lymphocyte count, CD3+ lymphocytes, LDH, total metabolic tumor volume, CRP, ferritin. Comparisons done with Wilcoxon rank sum test. (B) Peak laboratory parameters: Ferritin, CRP, absolute lymphocyte count. Blue boxes, bars, dots and lines represent results of patients without CRS, red boxes, bars, dots and lines those with CRS. CRP: C reactive protein; CRS: cytokine release syndrome; LDH: Lactate dehydrogenase. Comparisons done with Wilcoxon rank sum test. (C) Mean CAR-T transgene expansion, measured by qPCR, 6, 14, 21 and 30 days after infusion. N = 13. Comparisons done with Wilcoxon rank sum test. **p < 0.01. (D) Scatterplot of CAR-T expansion measured by qPCR, trends generated by locally estimated scatterplot smoothing (loess), AUC of CAR-T transgene (copy/pg DNA x days), n = 13, compared with Wilcoxon rank sum test, p = 0.16. Blue boxes, bars, dots and lines represent results of patients without CRS, red boxes, bars, dots and lines those with CRS. AUC, Area under the curve; CRP, C reactive protein; CRS, cytokine release syndrome; LDH, Lactate dehydrogenase qPCR, quantitative polymerase chain reaction.

Figure 2

Cytokine changes in CAR-T cell patients treated with prophylactic tocilizumab, (n = 13). (A) Median fold change from baseline (pre-lymphodepletion) over time in plasma cytokine concentrations in patients with CRS (left panel) and without CRS (right panel). Days are represented on the horizontal axis. Larger increases from baseline are shown in the green – yellow spectrum. Gray tiles represent missing values. (B) Comparisons of mean plasma cytokine concentrations of patients with CRS and without CRS (Wilcoxon test). Red tiles denote p values < 0.05. Not significant values (NS) are noted with black tiles.

Figure 3

Cytokine changes in CAR-T cell patients treated with prophylactic tocilizumab (n = 13). Scatterplots of cytokine concentrations measured by electrochemiluminescence. Trends generated by locally estimated scatterplot smoothing (LOESS). AUC of cytokine concentration (pg/mL x days) compared with Wilcoxon rank sum test. Blue dots and lines represent patients without CRS, red dots and lines represents patients with CRS. AUC, Area under the curve; CRS, cytokine release syndrome; INFγ, interferon gamma; IL, interleukin; MCP, monocyte chemoattractant protein; MIP, Macrophage inflammatory protein; TNFα, tumor necrosis factor alpha. A. Boxplot of time – based changes in cytokine concentrations with statistically significant differences between patients with CRS (red) and without CRS (blue). Comparisons done with Wilcoxon test.