Together with the check point T cell inhibition, Adoptive Cell Therapy (ACT) with chimeric antigen receptor (CAR) redirected T cells is perhaps, the most attractive anti-cancer strategy. CARs need to absolve dual function: antigen recognition and triggering of the lytic machinery of reprogrammed T cells. However, the full realization of the therapeutic potential of these approaches still relies on the possibility to overcome some of the limitations that obstacle the successful and the diffusion of clinical application of CAR-T cell-based immunotherapies. They are: the off-target toxicity, the cancer immune evasion, the high manufacturing cost and the elevated GMP standard conditions necessary for the production of viral vectors for cell transduction, safety for patients and operators.
We engineered two types of FcgR-CRs (CD16A-CR and CD64-CR equipped with CD28/z-chain signaling domains), to redirect T cell functions against opsonized tumor cells (Italian patent - Brevetto Italiano N° 0001429214). Among the advantages, "Universal FcgR-CRs" combine the mAbs therapeutic activities with a T cell-dependent activation at the tumor site, targeting antigens sequentially or in combination, according to appropriate administration of mAbs.
Furthermore, to advance the chimeric receptor towards its clinical application, we propose the transposon system PiggyBac in alternative to the viral-based systems for gene transduction of T lymphocytes.
In our application, we aim to:
a) verify the potentiality of using FcgR-CRs to kill opsonized acute myeloid leukemia (AML) cells.
b) optimize the strategy of gene delivery in cytokine-induced killer (CIK) and primary T cells using the transposon/transposase system PiggyBac.
We believe that our proposal indicates innovative aspects regarding methodology clinical relevance and economic impact.
Methodology:
Innovations are: a) use of CD16-CR and CD64-CR allowing the target of any tumor cell provided the availability of TAA-specific mAbs with required specificities; b) use of CIK cells expressing-CR in ACT; c) use of the transposon/transposase PiggyBac system for gene transduction.
In principle, ACT aimed to enhance ADCC through the administration of T cells expressing FcgR-CRs overcome the limitation of using CARs for each potential tumor antigen, while boosting the immune system with an antibody-dependent T cell response, and maintaining the biological and clinically relevant advantages the therapeutic mAbs necessary for treatment.
Furthermore, FcgR-CRs introduce a further level of control for safeness, represented by the natural Abs lifetime in the blood (about 3 weeks). This would be an intrinsic level to control CAR-T cells activity and off-target toxicity, with better chances to protect patients from GVH reactions.
Clinical relevance:
There is considerable evidence that CD123 has emerged as an attractive immunotherapeutic target for AML. This is supported by the differential expression of CD123 on leukemic stem cells and normal hematopoietic cells, which makes the CD123 a therapeutically important TAA.
Currently, several clinical trials in phase I and II are ongoing with SB-generated CD19 CAR-T cells, and one with MUC1-CAR for metastatic breast cancer is currently under review (US-1360).
Economic impact:
The overall study is expected to indicate parameters for the setup of protocols to produce FcgR-CRs-CIK and T cells and for the establishment of efficient, safe and certified bioprocesses that could be adopted by the biotechnology industries introducing transposons, including PiggyBac for gene transfer. This information represents a platform for developing FcgR-CRs-based targeted therapies (Italian patent - Brevetto Italiano N° 0001429214) of virtually any malignancies, as long as therapeutic mAbs with the appropriate specificity are available.