QC and Release Testing of Clinical Vector and Cell Gene Therapy Products

Division Of Basic Sciences - Nci

Investigators

Linked publications, trials & patents

Abstract

The SBQC team executes multiple assays to demonstrate conformance of viral and cell products manufactured both at the Surgery Branch and from external labs such as Contract Manufacturing Organizations (CMOs). All assays are executed according to specific GMP compliant SOPs and the specifications for product use are captured on the Certificate of Analysis (COA). These assays are complex cell-based, multi-day assays that are executed under time constraints to meet clinical patient treatment schedules. As each product (virus or cell) is unique and intended for a single, unique patient every vector and cell product must be tested (in contrast to bulk testing for a product administered to multiple patients). Both the vector (encoding a patient specific TCR targeting a mutant neoantigen) and the cells transduced with this vector must conform to the COA specifications. Some reagents such as the antigen presenting cells (APCs) required for co-culture cell based assays are generated and assessed in the SB-QCU for use in release testing. Unique APCs must be generated for each individualized therapy and can take 1 month to generate and test. To date, the unit has generated and banked B cells for every vector tested (to 80 banks). Release of Vector: The assays required to demonstrate that a vector produced at the SB or other facility is appropriate, safe and meets specification for clinical use are: vector titer, TCR specificity and presence (absence) of replication competent retrovirus, residual plasmid, residual benzonase endonuclease and sterility (microbiology, endotoxin and mycoplasma). All assays except the sterility assays are performed by the SB-QCU group. Release of Cell Products: The assays required to demonstrate that cellular products manufactured at the SB is appropriate, safe and meets specification for clinical use are: transduction efficiency, TCR specificity, presence (absence) of replication competent retrovirus, residual plasmid, residual benzonase endonuclease, vector copy number (per cell) and sterility (microbiology, endotoxin and mycoplasma). All assays except the sterility assays are performed by the SB-QCU group. The SB-QCU, since its inception in 2018, has performed testing on 80 individual vector products (20 since the last annual report) and 50 individual cellular products (15 since the last annual report). An unfortunate consequence of personalized therapies with long lead times from discovery of patient specific TCRs through to a vetted patient treatment is that many vector products are made but not used as the patient becomes ineligible due to disease progression before the treatment is ready. This is the primary cause for the discrepancy in vectors tested for clinical use versus patient products generated for treatment/infusion. Other unique factors of the trials supported by this project are that some vectors are made for allogeneic use (TCR identified in another patient, but vector used in manufacturing of patient autologous cells for treatment) as well as some TCRs are transferred to clinical vector production but the data generated by the research team is either incomplete or cannot be replicated using the GMP-qualified assays. The team has recently expanded to begin development of new assays or implementation of existing assays that were not a part of the unit portfolio to support upcoming IND submissions as well as INDs with low or infrequent enrollment (prior to 2018, the SB-QCU did not exist and assays were carried out by manufacturing personnel). The new (4) or resurrected (3) assays include flow cytometry, PCR, qPCR and cell-based assays (ELISA read-out).