jondoeuk
3 months ago
(OT) Artec Biotech is built upon methods for differentiating iPSCs into NK cells, as well as proprietary modifications. One example is the alteration of checkpoint receptors, such as PD-1 KO, which will be used for ART-002. The lead is ART-001, an unmodified NK product.
Although iPSC-NKs and PB-NKs of the same donor exhibited similar gene expression profiles, analysis revealed notable differences in genes that are important for NK cell function. Some of these genes were highlighted. Given the success of checkpoint inhibition in treating certain types of cancer, they evaluated checkpoint receptor expression in iPSC-NKs compared to PB-NKs. As demonstrated by a recent study, the expression of multiple checkpoint inhibitors was significantly higher in CD73+ cells, and the frequency of CD73+ cells correlated with larger tumour size in breast cancer patients https://www.jci.org/articles/view/128895
In their differentiation system, they produced NKs with down-regulated CD73 expression.
The next gene of interest was PTGER4, which encodes prostaglandin E2 receptor 4 (EP4). In NK cells, the binding of prostaglandin E2 to the receptor can initiate immunosuppression. In contrast, EP4 inhibition has been shown to enhance NK antitumour activity https://www.tandfonline.com/doi/full/10.1080/2162402X.2021.1896643
EP4 was down-regulated.
TIGIT was another gene of focus. Although not expressed in iPSC-NKs, it was highly expressed in PB-NK control. Overall, TIGIT is variably expressed in human NKs. Notably, NKs with lower TIGIT expression have exhibited higher cytokine secretion capability, degranulation activity, and cytotoxic potential https://onlinelibrary.wiley.com/doi/10.1002/eji.201545480
Furthermore, blocking TIGIT expression via monoclonal antibodies alleviated NK exhaustion https://www.nature.com/articles/s41590-018-0132-0
Similar to TIGIT, cytokine-inducible Src homology 2–containing protein (CIS), encoded by the CISH gene, is also involved in cytokine secretion. CIS is a member of the suppressor-of-cytokine signaling family of proteins. CISH deletion in either iPSC-NKs or PB-NKs increases their sensitivity to IL-15 and enhances JAK/STAT and mTORC1 signaling. This leads to increased NK metabolic fitness that contributes to an improved antitumour response https://ashpublications.org/blood/article/137/5/624/463715/Targeting-a-cytokine-checkpoint-enhances-the
Their iPSC-NKs have significantly down-regulated CISH expression compared to PB-NKs.
Aside from direct mechanisms that tumours employ to down-regulate NK function, the tumour microenvironment also impairs NK function by negatively affecting NK metabolism https://www.frontiersin.org/articles/10.3389/fimmu.2019.02278/full
Enhancing NK metabolic functionality is currently being pursued as one of the avenues for increasing NK cell activity against tumours https://www.pnas.org/doi/10.1073/pnas.2107507118
Considering this, they further evaluated the metabolic profile of iPSC-NKs and PB-NKs. The assessment focused on significantly expressed genes, which impact NK metabolic function. The following genes showed up-regulation in iPSC-NKs: Slc2a1 (involved in glucose transport), Slc7a5 (an amino acid transporter), Slc3a2/CD98 (an amino acid transporter), and TFRC/CD71 (involved in receptor-mediated iron uptake). These data yield insight into the efficacy of iPSC-NKs because nutrient transport is essential and increased expression of nutrient transporters promotes an increased metabolic rate, as well as elevated NK activity https://stemcellres.biomedcentral.com/articles/10.1186/s13287-021-02377-8
jondoeuk
5 months ago
Yes, that was one of at least five (from memory) trials testing aNKs (non-engineered NK-92s).
In metastatic pancreatic IBRX tested low-dose nab-paclitaxel, gemcitabine, aldoxorubicin, cyclophosphamide, low-dose SBRT, N-803 (an IL-15 superagonist) and PD-L1 CAR-NKs.
In all patients (3rd to 6th line) mOS is 5.8 months; median PFS 2.3 months. In 3rd line, mOS is 6.3 months. While this exceeds historical results, there were no controls.
Going forward (for other types), they plan on adding a number of other agents, including a heterologous prime-boost vaccine.
jondoeuk
5 months ago
Has any bio co-cultured their CARNK with TAM and cancer cell lines?
No, but one of the co-founders of Shoreline showed that while macrophages alone did not kill AML blasts, the addition of NKs (both without a CAR) significantly improved killing of AML blasts by half. The addition of an anti-CD47 mAb further increased killing by 23%.
Another (academic) group has created iPSC-derived CAR-macrophages, CAR-NKs, CAR-eosinophils, and CAR-neutrophils. Some of the preclinical data shows that both CAR-M and CAR-NK suppressed cancer cell survival more efficiently than either alone, even at higher doses of these cells. Also that the phagocytosis activity of CAR-M was increased in the presence of CAR-NK. In addition, CAR-eosinophils improved CAR-NK activity, and CAR-M with CAR-eosinophils enhance the activity of CAR-NK.
Anyone testing CARNK + ATEZO?
Not that I'm aware. One group showed that combination of allo NKs with pembrolizumab was well-tolerated and improved PFS and OS in patients (with NSCLC) compared with pembrolizumab alone https://www.jci.org/articles/view/132712
Also, a PhI testing allo tumour-reactive PD-L1+ NKs engineered to express soluble IL-15 in patients with NSCLC refractory to PD-1/PD-L1 inhibitors is ongoing.
jondoeuk
6 months ago
Trogocytosis has been documented for other leukocytes, including T-cells. In this paper, CAR-T cells were also shown to exhibit it when co-cultured with different types of cancer cells, including CARs that used the high-affinity CD19 binding domain FMC63 (most CAR-T therapies use it) https://www.nature.com/articles/s41586-019-1054-1
Similarly, it can be triggered by engagement of the CD16 receptor on NKs with mAbs leading to reduced efficacy https://ashpublications.org/blood/article/125/5/762/34055/Fc-receptor-mediated-trogocytosis-impacts-mAb https://aacrjournals.org/clincancerres/article/22/21/5211/79645/Checkpoint-Inhibition-of-KIR2D-with-the-Monoclonal
In this, they investigated if it contributed to (anti-CD19) CAR-NK cell fratricide and tumour progression in patients with lymphoid malignancies treated in a previously reported trial https://www.nature.com/articles/s41591-022-02003-x
Using blood samples collected at multiple time points after CAR-NK cell infusion, patients were divided into two groups based on the overall trogocytosis expression on CAR-NK cells [high (n=4) vs. low (n=7)]. It was found that acquisition of trogocytosised CD19 expression on CAR-NK cells was associated with a reduction in CD19 expression on B-cells and a higher probability of relapse (3 of 4 patients) compared to patients in the low group (0 of 7 patients). Also, expression was associated with improved clinical response. Those with a lower level had improved responses (100% ORR vs. 25% ORR).
They hypothesised that an inhibitory CAR, which incorporated an scFv directed to an NK-specific antigen linked to a inhibitory signal might overcome it. To determine that, they synthesised a CAR that recognised an NK self antigen. This was done by fusing the transmembrane and intracellular domains of a CAR with an scFv targeting CS1, a co-receptor that is expressed on all normal NKs, but absent on most CD19+ lymphoid-derived malignancies.
While this did not impact the extent of trogocytosis, they observed less trogocytosis-mediated in vivo fratricide (NK self killing), as evidenced by the better cell viability, higher persistence and improved effector functions compared with control groups.
So, companies should be able to address it, but I'm not aware of any that currently are.