Preclinical evaluation of CAR20(NAP)-T cells for B cell lymphoma

CD19-targeted CAR-T cell therapy has shown striking results against B cell malignancies, which has led to the approval of four CD19CAR-T cell products in the USA and EU. However, in long-term follow up evaluations it has become evident that many patients relapse after CD19CAR-T cell treatment and then in many cases present with CD19-negative tumors. In that case renewed CAR-T cell therapy targeting CD20 could be an option for lymphoma patients. Our previous study showed that CAR-T cells armed with immunomodulatory neutrophil-activating protein (NAP) from Helicobacter pylori (termed CAR(NAP)-T) can trigger the endogenous T-cell mediated immune response and further eliminate “CAR-target-antigen-negative” tumor cells. Here, we report the development of CD20-targeted (targeting moiety from Rituximab) CAR-T cells (CAR20-T cells), as well as the NAP-armed CAR20(NAP)-T cells and their pre-clinical evaluations in a murine lymphoma model. CAR20-T cells displayed efficient and specific cytotoxic potential against multiple human B cell lymphoma cell lines in vitro . In addition, primary mantle cell lymphoma cells isolated from a patient who relapsed after Rituximab treatment were also killed by CAR20-T cells. CAR20(NAP)-T cell treated mice showed delayed tumor growth and prolonged survival and NAP did not induce any severe toxicity. Human blood from healthy volunteers was exposed to recombinant NAP protein in an ex vivo human whole blood loop assay, without resulting in excessive cytokine release of immune cell activation, indicating a safe profile as a therapeutic transgene. CAR20(NAP)-T cells are worth further investigation especially in patients relapsing with CD19-negative tumors after CD19CAR-T cell therapy.