Cell and Gene Therapy Answers: What Sets Regenerative Cell Therapy Apart?

As cell therapies continue to reshape the future of medicine, developers must address distinct challenges for each therapeutic approach or specific cell type employed.  Regenerative cell therapy presents complexities and opportunities within this rapidly evolving field. We spoke with Erin Slosarek, Toxicology/Cell & Gene Therapy Study Director, Labcorp, to discuss four critical aspects of regenerative cell therapy development: defining features of regenerative vs adoptive cell therapies, strategies for translational success, unique regulatory challenges and key considerations for dose formulation. Here’s what you need to know.

How does development of regenerative cell therapies differ from other cell therapy programs?

Regenerative and adoptive cell therapies represent two distinct categories within the broader field of cell   therapy, each with unique biological mechanisms and therapeutic goals. Regenerative approaches rely on stem cells or progenitor cells, such as mesenchymal stromal cells or induced pluripotent stem cells, to repair or replace damaged tissues. Their primary objective is to restore normal tissue function through differentiation, engraftment, or paracrine effects. In contrast, adoptive cell therapies, such as CAR-T and TCR-T cells, harness or engineer mature immune cells to directly target and eliminate diseased cells, most often in oncology or infectious disease settings.

These fundamental biological differences drive distinct priorities in drug development. For regenerative therapies, long-term safety and controlled differentiation are paramount, as cells must persist and integrate without triggering tumorigenesis or inappropriate tissue formation. Manufacturing consistency and scalable production of uniform cell populations are also critical, alongside robust potency assays that demonstrate functional tissue repair. Conversely, adoptive cell therapies prioritize immune potency and functional cytotoxicity, with development programs centered on monitoring cellular kinetics, persistence, and controlled expansion post-infusion. Safety concerns for adoptive cell therapies are focused less on tumorigenicity and more on immune-mediated toxicities such as cytokine release syndrome and neurotoxicity. 

Strategically, regenerative cell therapies are directed toward chronic diseases and tissue repair, requiring extended regulatory follow-up and emphasis on long-term integration. Adoptive therapies, by contrast, dominate immuno-oncology pipelines, where rapid, potent, and durable but transient immune responses are essential to therapeutic success. As a result, regenerative programs are shaped by the need for sustained safety and tissue-specific functionality, while adoptive programs are defined by their emphasis on potency, persistence, and strategies to mitigate acute immune-related risks.

How can an integrated approach to species selection and the use of immunodeficient models improve the translational success of regenerative cell therapeutics?

Immunodeficient rodent models have proven highly valuable for initial proof-of-concept studies because they permit human cell engraftment and persistence. These models are especially useful for biodistribution, tumorigenicity, and early efficacy assessments, providing critical safety and mechanistic data in a controlled preclinical setting. Nonetheless, differences in cytokine signaling, extracellular matrix interactions, and tissue physiology can limit the ability of rodent systems to fully predict human regenerative outcomes, particularly for complex functional endpoints. 

While immunodeficient models help overcome rejection barriers, they introduce their own challenges. For example, immunodeficient rodents lack adaptive immunity but retain elements of innate immune function that may impact long-term engraftment. Moreover, because these models do not capture the complete interplay between immunity and tissue repair, they cannot fully replicate the biological environment in which regenerative therapies act. For this reason, rodent studies are typically complemented by immunosuppressed large animals that better represent human anatomy, physiology, and immunology particularly when evaluating organ-level function, integration, and durability of effect. 

An ideal approach to meet these challenges combines rodent models with advanced large-animal platforms, including minipigs and non-human primates. Minipigs provide close anatomical and physiological similarity to humans in areas such as cardiovascular, neurological, ocular, and musculoskeletal biology, and non-human primates offer unparalleled translational relevance for similar endpoints. Finally, integrating sensitive molecular assays—qPCR, ddPCR, and NGS—for persistence and biodistribution with functional assessments in appropriate large-animal models enables comprehensive evaluation of regenerative therapies. This tiered approach can leverage the strengths of rodent and large-animal models to generate robust, regulatory-aligned preclinical packages.

What regulatory challenges should developers anticipate for regenerative cell therapeutics?

1. Safety is a primary regulatory focus in regenerative cell therapy, as the persistence and plasticity of stem and progenitor cells raise concerns about tumorigenicity, inappropriate differentiation, and off-target effects. Regulators require long-term safety studies to detect late-emerging risks, and biodistribution assays to ensure cells do not migrate to unintended tissues. Validated tumorigenicity platforms in immunodeficient rodent models complement sensitive molecular assays to quantify biodistribution, persistence, and genomic stability to provide robust, regulatory-aligned data packages to support the demonstration of long-term safety.
2. Cell identity and viability also represent critical regulatory challenges, as product consistency must be demonstrated across heterogeneous populations. Regulators expect detailed characterization of cellular phenotype, potency, and viability both at release and during stability testing, with assays that meaningfully reflect the intended mechanism of action. Advanced flow cytometry, imaging, and molecular profiling platforms, ensure precise cell characterization and alignment with regulatory expectations. Customized potency assays are developed to link biological activity to therapeutic intent, strengthening regulatory submissions.
3. Engraftment and immune response present further regulatory hurdles since regenerative therapies are intended to integrate into host tissues while avoiding immune rejection. Preclinical packages must demonstrate not only whether cells persist, but also how they interact with host physiology and immunity over time. Relevant models range from immunocompromised rodents that readily enable engraftment studies to large animals such as minipigs and non-human primates that provide translationally relevant data on functional integration. Genetically humanized rodent models assess immune compatibility, complemented by immunophenotyping and cytokine profiling of host immune responses.

Are there special considerations for dose formulation of regenerative cell therapeutics?

Regenerative cell therapy presents unique challenges because living cells must remain viable, functional, and phenotypically stable from manufacturing through dose administration. Unlike small molecules or biologics, regenerative products cannot be sterilized terminally, and factors such as cell density, suspension medium, cryopreservation methods, and delivery routes can directly affect engraftment, therapeutic potency, and safety. Regulators also expect integration of pharmacokinetic and toxicokinetic (PK/TK) assessments, which in this context involve tracking biodistribution, persistence, and functional activity of cells over time to establish exposure–response relationships and inform dose selection. Cell formulation strategies that optimize stability, viability, and functional integrity across preclinical studies can include customized cryopreservation and thawing protocols, compatibility testing with administration routes and devices, and in vivo PK/TK assessments of persistence, biodistribution, and potency in relevant animal models.