CAR-NK

What is CAR-NK?

CAR-NK is a genetically modified cell therapy in which an artificial receptor (CAR), combining an antigen-binding site (such as an scFv) and T-cell receptor signaling domains (such as CD3ζ, 4-1BB/CD28), is introduced into autologous or allogeneic NK cells derived from the patient. Starting with the high clinical efficacy demonstrated in hematological cancers,BCMA-targeted, allogeneic "off-the-shelf" products, and next-generation designs aiming for expanded indications to solid tumors (such as ARMOR and logic-gated CARs)Drug discovery and development are progressing toward [this goal]. Compared to CAR-T cells, safety and versatility leveraging the characteristics of NK cells are also expected.

Representative examples of CAR-NK

Since there are no approved CAR-NK drugs at present (as of the end of July 2026), we have selected three approaches from "representative pioneering clinical investigational drugs and technological concepts currently undergoing clinical development" that differ in their source cells and CAR structures, making them easy to compare.

Cord blood (CB)-derived CAR-NK (IL-15 co-expressing) cells

Umbilical cord blood (CB)-derived CAR-NK is a pioneering approach undergoing clinical development at institutions such as MD Anderson Cancer Center. Targeting CD19,Enhancing the in vivo persistence of NK cells by incorporating an autocrine IL-15 supply cassetteThe design is a defining feature.

iPS cell-derived CAR-NK (iNK) cells

iPS cell-derived CAR-NK (iNK) cells represent an approach exemplified by Fate Therapeutics' FT596. By genetically modifying them at the iPS cell stage,It can be mass-produced as a completely off-the-shelf product with uniform quality.It features points. Furthermore, we aim to achieve multi-functionality by incorporating high-affinity CD16 and NKG2D signals (DAP10/DAP12), among others.

CAR-NK derived from NK-92 cell line

CAR-NK derived from the NK-92 cell line is an approach based on established NK-92 cells, with targoNK-92 as an example. Its advantages are consistent quality and ease of large-scale culture. On the other hand, since radiation is required for clinical use,Molecular design taking into account in vivo persistence and effects on PK due to growth arrestis important.

Important challenges in CAR-NK development

Low in vivo persistence and rapid attenuation of proliferative capacity

Compared to T cells, NK cells have a shorter in vivo half-life and rapidly undergo apoptosis without cytokine support such as IL-15 or IL-2.Quantify the correlation between blood/tissue persistence and therapeutic efficacy in non-clinical models, and establishing an evaluation system capable of predicting clinical persistence is an important challenge.

The intrinsic "inhibitory receptor signaling" of NK cells and their inactivation by the tumor microenvironment (TME)

Even if a tumor is recognized by CAR, negative signals from inhibitory receptors such as KIR or NKG2A via HLA class I cancel out the killing ability. Furthermore, in the TME of solid tumors,TGF-β and hypoxia decrease activating receptors such as NKG2D, leading to the progression of NK cell dysfunction.That is the challenge.

Low efficiency of gene transfer into primary cells and functional decline after freeze-thaw (post-thaw)

Primary NK cells are highly resistant to retroviral or lentiviral infection, making it difficult to achieve a sufficient CAR expression rate. Furthermore, upon freeze-thawing, which is essential for off-the-shelf products,Cell recovery rate (recovery) and killing capacity (kill rate) tend to decrease easily due to membrane damage or reduced activity.becomes an important manufacturing and quality challenge.

Non-clinical evaluation required for CAR-NK

Rating 1: "IL-15-introduced humanized mouse PK/CK (Cellular Kinetics) evaluation reproducing human NK engraftment and cytokine dynamics"

Standard NSG mice lack human IL-15, making it impossible to properly evaluate CAR-NK persistence. Therefore, using NSG-hIL15 mice,Simultaneous measurement of CAR gene copy number by ddPCR/qPCR and tumor/cell kinetics by BLI to evaluate the correlation among dose, persistence, and efficacyis important.

Evaluation 2: Elucidating the NK cell-specific receptor network and TME resistance using "Single-Cell Multi-Omics analysis"

In CAR-NK cells, in addition to antigen recognition by CAR, it is important to capture the balance of activating and inhibitory receptors that change in the TME.Analyze the expression of KIR, NKG2A, TIGIT, etc., and the maintenance of Perforin and Granzyme B at the single-cell level using scRNA-seq, CITE-seq, and CyTOF., and identify the mechanism of functional decline in the TME.

Rating 3: "Post-thaw function and recovery evaluation system" ensuring the practical application of off-the-shelf products

For off-the-shelf formulations, it is important that CAR-NK function is maintained even after freeze-thawing.Evaluate sustained cytotoxicity by RTCA, degranulation capacity by CD107a, and responsiveness to serial antigenic stimulation (re-challenge), and confirm post-thaw viability and killing capacity.Therefore, we verify the validity of the manufacturing and formulation processes.

Rating 4: Integrated safety profiling of "GvHD, off-target toxicity, and allogeneic immune responses" in allogeneic-heterologous use

For allogeneic CAR-NK cell therapies, it is necessary to comprehensively evaluate GvHD caused by residual T cells, on-target/off-tumor toxicity, and alloimmune responses.Combining MLR using PBMCs, cross-reactivity with normal tissue organoids, and ultra-sensitive detection of residual CD3+ cells to establish safety margins and quality control standards.is important.

Key points when choosing a contract research organization (CRO) for non-clinical studies

In CAR-NK non-clinical development, simply measuring PK (Persistence) is not enough. In addition to efficacy evaluation, it is crucial to have a system capable of consistently evaluating disease models, the TME (tumor microenvironment), and resistance models. In particular, selecting a CRO that can integrate these to generate data with high clinical extrapolability is a key factor for development success.