Chidamide Bridging for CAR-T Therapy

Background: CAR-T cell therapy has been shown to be superior to conventional therapy in patients with r/r B-cell NHL. However, prior clinical studies and real-world data suggest that approximately 30-40% of cases of drug resistance still occur after CAR-T cell therapy, and approximately 50-60% of cases have recurrent disease progression over time of infusion. The investigators used genome-wide CRISPR/Cas9 to screen for CAR T-resistant cells and identified low NOXA expression as associated with CAR-T resistance. NOXA protein is a member of the Bcl2 protein family, which plays a critical role in P53-dependent apoptosis. The previous research suggests that the low expression of NOXA protein may be an important biomarker for the treatment of drug resistance of CAR-T cells. Through the verification of nearly 40 clinical samples previously treated with CAR-T, the investigators found that low NOXA expression was associated with poor prognosis. Meanwhile, animal experiments demonstrated that HDACi can up-regulate the expression of NOXA in tumor cells and significantly improve the efficacy of CAR-T therapy by reducing the incidence of resistance. The research was published in Signal Transduction and Targeted Therapy in 2022. Objective: The primary objective of the study was to evaluate whether chidamide bridging intervention improved clinical response to CAR-T in patients with r/r B-cell NHL. A secondary objective was to evaluate the safety of bridging therapy with chidamide and subsequent CAR-T infusion in above patients. The exploratory objective was to investigate the effect of chidamide intervention on NOXA expression. Design: This is a multicenter, prospective, controlled, open-label, phase Ⅰ/Ⅱ study. 120 patients with r/r B-cell NHL will be enrolled. Biopsy was performed before peripheral blood mononuclear cell (PBMC) collection, and NOXA expression level was detected by immunohistochemistry (IHC). Patients with high NOXA expression (IHC score \> 4) were treated with conventional CAR-T process (n=60), including PBMC collection, bridging therapy (without chidamide), fludarabine and cyclophosphamide (FC) regimen conditioning, CAR-T cell infusion, efficacy evaluation and follow-up; Patients with low NOXA expression (IHC score 0 - 4) were randomly assigned 1:1 to conventional CAR-T group as mentioned earlier (n=30) or CAR-T group containing chidamide bridging therapy (n=30). The bridging therapy regimen containing chidamide was divided into monotherapy and combination therapy. Chidamide combination intervention can be used in cases of high tumor burden, rapid progression of disease, symptoms of compression, involvement of specific sites or organs, and other burden reduction that need to be addressed. The combination of one or more of the following drugs in addition to chidamide is permitted: glucocorticoids, BTK inhibitors, chemotherapy, other previously used resistance drugs, etc. In this study, commercial CAR-T cells (mainly Relma-cel, with Axi-cel or other commercial CAR-T cells also acceptable) or experimental CAR-T cells targeted at CD19 were acceptable. If feasible, for the group with low NOXA expression, a secondary biopsy was performed at the same site to detect changes in NOXA expression before CAR-T infusion.