Patients with refractory and/or recurrent B cell malignancies have poor prognosis despite complex multimodal therapy. Despite impressive progress, more than 50% of patients treated with CD19-targeting chimeric antigen receptor T cells (CAR19) experience progressive disease. Further, more than 40% patients with progressive large B cell lymphoma (LBCL) experienced reduced or lost expression of CD19 on the tumor cells after CAR19 treatment; low surface CD19 density before treatment was associated with progressive disease. Therefore, novel curative approaches are needed. The investigation attempts to use genetically modified T cells to express a 4th generation lentiviral anti-CD19/70 bi-specific CAR (bi-4SCAR-CD19/70). The CAR molecules enable the T cells to recognize and kill tumor cells through the recognition of a surface antigen, CD19 or CD70, which is expressed at high levels on tumor cells but not at significant levels on normal tissues.~CD70 is highly expressed in many cancers, but limited in normal tissues, it is a potential CAR-T therapeutic target. Expression of CD70 was observed on multiple tumor types including solid tumor as well as B cell malignancies. In addition, it has been reported that anti-CD70 CAR T-cells can eliminate CD70-positive cells and exhibit strong anti-tumor effects in preclinical animal models. The CD70 targeted CAR-T cells with binding moiety of CD70 specific scFv exhibited a higher affinity and antitumor effect against CD70-positive tumor cells. A potential strategy to prevent relapse due to antigen escape is to infuse T-cells capable of recognizing multiple antigens.~To overcome tumor escape of single target antigen and enhance in vivo CAR-T efficacy, a novel bi-specific CD19/70 CAR-T therapy regimen is developed to include booster and consolidation CAR-T applications to target highly-refractory B cell cancer. The aim is to evaluate safety and long term efficacy of the bi-CAR-T therapy strategy in CD19 and/or CD70 positive cancer patients.
The purpose of this study is to assess the feasibility, safety and efficacy of CD19/70 bi-specific CAR-T cell therapy in patients with CD19 and/or CD70 positive B cell malignancies. Another goal of the study is to learn more about the safety and function of the anti-CD19/70 bi-specific CAR-T cells and their persistency in patients.