CAR T Cells in Trials: Recent Achievements and Challenges that Remain in the Production of Modified T Cells for Clinical Applications

Abstract

The adoptive transfer of chimeric antigen receptor (CAR)-modified T cells is attracting growing interest for the treatment of malignant diseases. Early trials with anti-CD19 CAR T cells have achieved spectacular remissions in B-cell leukemia and lymphoma, so far refractory, very recently resulting in the Food and Drug Administration approval of CD19 CAR T cells for therapy. With further applications and increasing numbers of patients, the reproducible manufacture of high-quality clinical-grade CAR T cells is becoming an ever greater challenge. New processing techniques, quality-control mechanisms, and logistic developments are required to meet both medical needs and regulatory restrictions. This paper summarizes the state-of-the-art in manufacturing CAR T cells and the current challenges that need to be overcome to implement this type of cell therapy in the treatment of a variety of malignant diseases and in a greater number of patients.

B Cell-Based Cancer Immunotherapy

“…Thus, a tumor entity should be chosen where TILs are easily assessable, i.e., surgery is part of the standard procedure, a possible tumor antigen for pulsing is known, and where there is a great clinical need. Manufacturing of B cells under GMP-conditions comprises no obstacles anymore after today’s experience with CAR trials [86] and B cell-adoptive transfer [81], and suitable tumor antigens for pulsing have been discovered in many solid tumor entities [87]. The whole isolation and activation process of CD40B cells in general would also be suitable for an automated manufacturing process, e.g., in the CliniMACS Prodigy (Miltenyi Biotec) [88].…”

Functionality and Cell Senescence of CD4/ CD8-Selected CD20 CAR T Cells Manufactured Using the Automated CliniMACS Prodigy® Platform

“…To date, release specifications of the final product include cell identity, vector copy number, microbiological, endotoxin, and mycoplasma testing, as well as flow cytometric quantification of transgene expression. The latter has so far been accepted as an indirect potency assay in early phase I/II trials and is partly combined with cytotoxicity assays against the respective target cells and/or quantification of cytokine secretion of the engineered T cells [12]. …”

CAR-T-Zellen: Update 2019

“…Durch den großen Erfolg von CAR-T-Zellen in der Krebstherapie stellt sich die Frage nach einem möglichen Einsatz bei anderen Krankheiten. fristig sollen regulatorische T-Zellen (T reg ) mit CAR-Expression Autoimmunkrankheiten sowie die Transplantatgegen-Wirt-Krankheit (graft-versus-host disease, GvHD) heilen [9].…”

“…Qualitätskontrollen werden vom Ausgangsmaterial, als In-Prozess-Kontrollen und vom Endprodukt durchgeführt [9]. Die Herstellung und Freigabe unterliegen getrennt jeweils dem Leiter der Herstellung und dem Leiter der Qualitätskontrolle und übergeordnet der Sachkundigen Person (qualified person, QP).…”

“…Da es zwischen den Herstellern grundsätzlich Unterschiede im CAR-Design, in der Geninsertion, Zellkultur und in den Zellaufreinigungstechnologien gibt, muss die Qualitätskontrolle den jeweiligen spezifischen Produktionsprozess berücksichtigen [18]. Des Weiteren sind Parameter wie das Ausgangsmaterial wichtige Einflussfaktoren, da beispielsweise eine intensive Vorbehandlung von Patienten mit oftmals kritischem Immunstatus eine hohe Variabilität des Zellmaterials zur Folge hat [9].…”