CMC Considerations for ex vivo vs in vivo CAR-T
In vivo CAR-T represents one of the most significant potential evolutions in the cell and gene therapy (CGT) landscape. By eliminating individualized ex vivo manufacturing and enabling direct generation of CAR-T cells within the patient, these approaches have greater potential to improve scalability, accessibility, and operational simplicity. However, in vivo CAR T also introduces new challenges related to targeted delivery, immunogenicity, quality control, and regulatory oversight.
While conventional ex vivo CAR-T CMC is focused on the manufacture and control of an engineered cellular product, in vivo CAR-T shifts the CMC focus toward on controlling a delivery platform that generates the cellular product inside the patient. As a result, CQAs move from cell-centric attributes such as viability and phenotype toward delivery-centric attributes such as vector potency, payload integrity, targeting specificity, purity, transduction efficiency and more.
Here’s a summary of the main CMC differences between ex vivo and in vivo CAR T:
CMC Comparison: Ex Vivo vs. In Vivo CAR T
| CMC Area | Ex Vivo CAR-T | In Vivo CAR-T |
|---|---|---|
| Drug Substance | Genetically modified autologous or allogeneic T cells |
Viral or non-viral delivery approaches can be used to deliver CAR-encoding genetic material to target T cells, enabling the generation of CAR-T cells directly within the patient. Viral approaches: targeted lentiviral vectors (tLVV) and AAV Non-viral approaches: targeted lipid nanoparticles (LNPs), polymeric nanoparticles, extracellular vesicles (EVs) |
| Primary Manufacturing Focus | Cell isolation, activation, transduction, expansion, harvest, cryopreservation | Vector or nanoparticle production, formulation, purification, and particle characterization |
| Critical Quality Attributes (CQAs) | Cell identity, viability, phenotype, transduction efficiency, potency, purity | Particle size/distribution, functional titer, encapsulation efficiency, targeting specificity, genomic integrity, potency, purity |
| Potency Strategy | Direct measurement of CAR-T cell function (cytotoxicity, cytokine secretion, activation markers) | Demonstration of successful target-cell transduction and functional CAR expression for in vitro efficacy |
| Process Controls | Cell activation and transduction conditions; culture parameters; cell expansion kinetics; in-process cell count and viability; harvest and formulation controls | Vector production or nanoparticle formulation parameters; raw-material and payload controls; purification and formulation parameters; payload integrity; critical in-process vector/particle attributes |
| Batch-to-Batch Variability | Significant due to patient-specific starting material | Potentially lower due to standardized manufacturing processes, although biological variability remains in vivo |
| Release Testing | Identity, viability, safety, potency, vector copy number | Physiochemical, identity, content, purity, potency, safety, vector/nanoparticle characterization |
| Supply Chain Model | Vein-to-vein, patient-specific logistics | Conventional drug distribution model with potential off-the-shelf inventory |
| Scalability | Limited by individualized manufacturing capacity | Potentially scalable through large-scale vector or nanoparticle manufacturing |
| Comparability Challenges | Manufacturing changes may affect cellular CQAs such as phenotype, CAR expression, purity, and potency | Manufacturing changes may alter delivery-product CQAs, potency, stability, targeting/transduction capability, or other attributes relevant to in vivo performance |
| Analytical Development Priorities | Cell identity and phenotype, CAR expression, purity, viability, potency, and safety testing | Platform-specific vector/particle characterization, payload characterization, purity, potency and targeting/transduction assays |
| Regulatory Focus | Manufacturing consistency and comparability, product quality, potency, cellular persistence, and long-term safety | Manufacturing consistency and comparability, potency and product quality with targeting efficiency and safety |
When transitioning from ex vivo to in vivo CAR-T development, success will depend on recognizing a fundamental shift in the therapeutic paradigm: the administered product is no longer a pre-manufactured population of engineered T cells, but an in vivo cell product designed to generate functional CAR-T cells within the patient. Rather than simply replacing a manufacturing process with a viral or non-viral targeted delivery system, it is crucial to adapt scientific, manufacturing, and regulatory strategies accordingly to capture the next wave of innovation in cell and gene therapy.
Your Strategic Partner for Targeted Immunotherapy
In vivo CAR-T calls for a partner who understands both the delivery platform and the cell it creates. ProBio brings these together with integrated plasmid DNA, antibody, targeted lentiviral vector (tLVV), and targeted lipid nanoparticle (RNA-tLNP) platforms, backed by phase-appropriate CMC strategy and IND-ready regulatory support. We’ll help targeted immunotherapy developers reduce risk, simplify development, and bring next-generation in vivo CAR-T programs to patients faster.