Phase I trials using Sleeping Beauty to generate CD19-specific CAR T cells

Abstract

BACKGROUND.T cells expressing antigen-specific chimeric antigen receptors (CARs) improve outcomes for CD19-expressing B cell malignancies. We evaluated a human application of T cells that were genetically modified using the Sleeping Beauty (SB) transposon/transposase system to express a CD19-specific CAR. METHODS.T cells were genetically modified using DNA plasmids from the SB platform to stably express a second-generation CD19-specific CAR and selectively propagated ex vivo with activating and propagating cells (AaPCs) and cytokines. Twenty-six patients with advanced non-Hodgkin lymphoma and acute lymphoblastic leukemia safely underwent hematopoietic stem cell transplantation (HSCT) and infusion of CAR T cells as adjuvant therapy in the autologous (n = 7) or allogeneic settings (n = 19).RESULTS. SB-mediated genetic transposition and stimulation resulted in 2,200-to 2,500-fold ex vivo expansion of genetically modified T cells, with 84% CAR expression, and without integration hotspots. Following autologous HSCT, the 30-month progression-free and overall survivals were 83% and 100%, respectively. After allogeneic HSCT, the respective 12-month rates were 53% and 63%. No acute or late toxicities and no exacerbation of graft-versus-host disease were observed. Despite a low antigen burden and unsupportive recipient cytokine environment, CAR T cells persisted for an average of 201 days for autologous recipients and 51 days for allogeneic recipients.CONCLUSIONS. CD19-specific CAR T cells generated with SB and AaPC platforms were safe, and may provide additional cancer control as planned infusions after HSCT. These results support further clinical development of this nonviral gene therapy approach.

Prolonged Expression of Secreted Enzymes in Dogs After Liver-Directed Delivery ofSleeping BeautyTransposons: Implications for Non-Viral Gene Therapy of Systemic Disease

“…[42][43][44] It remains to be seen whether the SB transposons can be used in the in vivo approach as successfully as they are being used to treat blood cancers in human patients. 71 …”

Debate: Transplant is Still Necessary in the Era of Targeted Cellular Therapy for ALL

“…The use of a non-viral transduction system allows greater facility in modification of CAR construct; phase I clinical trials use the Sleeping Beauty (SB) transposon/transposase system were completed and shown to be safe. 27 The SB system can adapt to express more than one transposon. In a technology dubbed "double transposition" three DNA plasmids (two transposons and one transposase) have been electro-transferred into T cells to co-express CAR and membrane-bound IL-15 (mbIL15).…”

Advances in cancer immunology and cancer immunotherapeutics

“…[76] The most investigated CAR cell therapy is against CD19 for B cell lineage malignancies with overwhelming response across multiple clinical trials. [77][78][79][80][81] Unfortunately, the data are not very encouraging in solid tumors. [82] Obvious on target-off tumor side effects should be expected as the target antigen might be expressed on the normal tissue.…”