Cellular Cancer Immunotherapy Development and Manufacturing in the Clinic

Abstract

The transfusion of naturally derived or modified cellular therapies, referred to as adoptive cell therapy (ACT), has demonstrated clinical efficacy in the treatment of hematologic malignancies and metastatic melanoma. In addition, cellular vaccination, such as dendritic cell-based cancer vaccines, continues to be actively explored. The manufacturing of these therapies presents a considerable challenge to expanding the use of ACT as a viable treatment modality, particularly at academic production facilities. Furthermore, the expanding commercial interest in ACT presents new opportunities as well as strategic challenges for the future vision of cellular manufacturing in academic centers. Current trends in the production of ACT at tertiary care centers and prospects for improved manufacturing practices that will foster further clinical benefit are reviewed herein.

Figure 1.

Overview of the culturing and selection of autologous TIL for use in ACT. A resected tumor sample is enzymatically digested and plated into a single cell suspension. Cell culture conditions are suitable only for lymphocyte growth, yielding a pure T-cell culture as tumor cells die out. TIL are selected on the basis of tumor reactivity and neoantigen specificity as demonstrated by co-culture and ELISA assays. Selected TIL are then rapidly expanded in culture supplemented with IL2, OKT3, and PBMC “feeder” cells, after which the cells are harvested and prepared for infusion back into the patient. (Adapted from an image created with BioRender.com.)

Figure 2.

Distinctions in the production of genetically engineered peripheral blood lymphocytes. Lentiviral or retroviral transduction of peripheral blood lymphocytes allows antitumor TCRs and CARs to be expressed in otherwise nonspecific T cells. T cells are harvested via leukapheresis and are activated prior to transduction. While transduction and expansion are similar, TCRs and CARs differ greatly in their structure, function, and selection. TCR selection requires tumor antigen screening and HLA matching to ensure proper recognition of an HLA-peptide complex presented to a TCR. Screening affinity-enhanced TCRs for off-target reactivity is also of great necessity, particularly when targeting TAAs, given past examples of severe toxicity after infusion. CAR genes are artificially designed and constructed out of a mAb-derived scFv, which binds directly to a tumor-associated surface antigen as well as intracellular signaling domains such as CD3ζ, CD28, and 4–1BB. (Adapted from an image created with BioRender.com.)

Figure 3.

General schema for the development and production of ex vivo stimulated DC vaccines. Patients undergo leukapheresis, after which the cell product is fractionated and monocytes are harvested. Monocytes are then cultured with stimulatory cytokines to generate immature DCs. Depending on the desired antigenic material, tumor harvested via biopsy or resection is used to generate tumor lysates, tumor mRNA, or antigen-specific peptides. Selected material is then pulsed into mature DCs, with the antigen-loaded DCs then being injected into the patient. (Adapted from an image created with BioRender.com.)

Figure 4.

Overview of adoptive cell therapies: their strengths, limitations, and promising new developments for academic production paradigms. The future of adoptive cell therapy at academic manufacturing centers will rely on the adoption and refinement of new technologies and production workflows. Academic centers must balance the unique strengths (indicated by “+” signs) and limitations (indicated by “−” signs) of each ACT modality with the logistical and regulatory pressures of GMP manufacturing at their respective institutions. The rapid development of closed-loop manufacturing systems, driven largely by industry and commercialization, and high-throughput cell sequencing platforms will enable the large-scale selection and expansion of T-cell products at academic centers. Associated protocols developed using these platforms will be crucial to future clinical trials, the development of academia-industry partnerships, and establishing ACT as a valuable component of cancer treatment for both hematologic and solid malignancies. (Adapted from an image created with BioRender.com.)