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Claudin-18 isoform 2 (CLDN18.2) has emerged as a promising therapeutic target in gastric or gastro-oesophageal junction cancer. Satricabtagene autoleucel (satri-cel; also known as CT041), an autologous CLDN18.2-specific chimeric antigen receptor (CAR) T-cell therapy, showed encouraging activity in previously treated patients with advanced gastric or gastro-oesophageal junction cancer in phase 1 clinical trials. In this Article, we report the primary results from the phase 2 pivotal trial (CT041-ST-01) investigating the efficacy and safety of satri-cel for gastric or gastro-oesophageal junction cancer. In this open-label, multicentre, randomised controlled trial conducted in China, patients with CLDN18.2-positive (immunohistochemistry expression intensity ≥2+ and positive tumour cells ≥40%) advanced gastric or gastro-oesophageal junction cancer, who were refractory to at least two previous lines of treatment, were randomly allocated (2:1) to receive satri-cel or treatment of physician's choice (TPC). In the satri-cel group, satri-cel was infused up to three times at a dose of 250 × 106 cells. For the TPC group, one of the standard-of-care drugs (nivolumab, paclitaxel, docetaxel, irinotecan, or rivoceranib [apatinib]) was given, per the physician's decision. Those who had disease progression or drug intolerance in the TPC group could receive subsequent satri-cel, if eligible. The primary endpoint was progression-free survival, assessed by an independent review committee, in the intention-to-treat population. This study is registered with ClinicalTrials.gov (NCT04581473), and is closed to new patients. Between March 22, 2022, and July 29, 2024, 266 patients were screened, of whom 156 were randomly allocated to the satri-cel group (n=104) or TPC group (n=52). 88 (85%) patients in the satri-cel group and 48 (92%) patients in the TPC group received study drug. In the satri-cel group, 28 (27%) patients had previously received three or more lines of treatment and 72 (69%) patients had peritoneal metastasis. In the TPC group, ten (19%) patients had previously received three or more lines of treatment and 31 (60%) patients had peritoneal metastasis. The median follow-up time for progression-free survival was 9·07 months (95% CI 6·21–13·01) in the satri-cel group and 3·45 months (2·89–not estimable) in the TPC group, based on the reverse Kaplan–Meier method. In the intention-to-treat population, median progression-free survival was 3·25 months (95% CI 2·86–4·53) in the satri-cel group and 1·77 months (1·61–2·04) in the TPC group (hazard ratio 0·37 [95% CI 0·24–0·56]; one-sided log-rank p<0·0001). In the safety analysis set (all patients who received at least one dose of study drug), grade 3 or higher treatment-emergent adverse events occurred in 87 (99%) of 88 patients in the satri-cel group and 30 (63%) of 48 patients in the TPC group. The most common grade 3 or worse treatment-emergent adverse events related to treatment were decreased lymphocyte count (86 [98%] of 88 patients), decreased white blood cell count (68 [77%] patients), and decreased neutrophil count (58 [66%] patients) in the satri-cel group. Cytokine release syndrome occurred in 84 (95%) of 88 patients in the satri-cel group. This is the first randomised controlled trial of CAR T-cell therapy in solid tumours globally. Satri-cel treatment resulted in a significant improvement in progression-free survival, with a manageable safety profile. These results support satri-cel as a new third-line treatment for advanced gastric or gastro-oesophageal junction cancer patients. CARsgen Therapeutics.

Chimeric antigen receptor (CAR)–T cells have shown efficacy in patients with B cell malignancies. Yet, their application for solid tumors has challenges that include limited cancer-specific targets and nonpersistence of adoptively transferred CAR-T cells. Here, we introduce the developmentally regulated tight junction protein claudin 6 (CLDN6) as a CAR target in solid tumors and a strategy to overcome inefficient CAR-T cell stimulation in vivo. We demonstrate that a nanoparticulate RNA vaccine, designed for body-wide delivery of the CAR antigen into lymphoid compartments, stimulates adoptively transferred CAR-T cells. Presentation of the natively folded target on resident antigen-presenting cells promotes cognate and selective expansion of CAR-T cells. Improved engraftment of CAR-T cells and regression of large tumors in difficult-to-treat mouse models was achieved at subtherapeutic CAR-T cell doses.

Targeted therapy and immunotherapy have revolutionized treatment of various cancers in the past decade. Despite targeted therapy with trastuzumab in Her2-positive gastric cancer patients, survival has been dismal, mostly due to disease progression and toxicity related to the treatments. One area of active development is looking for ideal monoclonal antibodies (IMAB) specific to the proteins only on the tumor and hence avoiding unnecessary side effects. Claudin proteins with isoform 2 are one such protein, specific for several cancers, particularly gastric cancer and its metastases, leading to the development of anti-claudin 18.2 specific antibody, claudiximab. This review will highlight the latest development of claudiximab as first in class IMAB for the treatment of gastric cancer.

Background Autism spectrum disorders (ASD) are complex conditions whose pathogenesis may be attributed to gene–environment interactions. There are no definitive mechanisms explaining how environmental triggers can lead to ASD although the involvement of inflammation and immunity has been suggested. Inappropriate antigen trafficking through an impaired intestinal barrier, followed by passage of these antigens or immune-activated complexes through a permissive blood–brain barrier (BBB), can be part of the chain of events leading to these disorders. Our goal was to investigate whether an altered BBB and gut permeability is part of the pathophysiology of ASD. Methods Postmortem cerebral cortex and cerebellum tissues from ASD, schizophrenia (SCZ), and healthy subjects (HC) and duodenal biopsies from ASD and HC were analyzed for gene and protein expression profiles. Tight junctions and other key molecules associated with the neurovascular unit integrity and function and neuroinflammation were investigated. Results Claudin ( CLDN )-5 and -12 were increased in the ASD cortex and cerebellum. CLDN-3 , tricellulin , and MMP-9 were higher in the ASD cortex. IL-8 , tPA , and IBA-1 were downregulated in SCZ cortex; IL-1b was increased in the SCZ cerebellum. Differences between SCZ and ASD were observed for most of the genes analyzed in both brain areas. CLDN-5 protein was increased in ASD cortex and cerebellum, while CLDN-12 appeared reduced in both ASD and SCZ cortexes. In the intestine, 75% of the ASD samples analyzed had reduced expression of barrier-forming TJ components ( CLDN-1 , OCLN , TRIC ), whereas 66% had increased pore-forming CLDNs ( CLDN-2 , -10 , -15 ) compared to controls. Conclusions In the ASD brain, there is an altered expression of genes associated with BBB integrity coupled with increased neuroinflammation and possibly impaired gut barrier integrity. While these findings seem to be specific for ASD, the possibility of more distinct SCZ subgroups should be explored with additional studies.

Claudin18.2 (CLDN18.2) is highly expressed with the development of various malignant tumors, especially gastrointestinal cancers, and is emerging as a new target for cancer treatment. Satricabtagene autoleucel (satri-cel)/CT041 is an autologous chimeric antigen receptor (CAR) T cell targeting CLDN18.2, and the interim results of the CT041-CG4006 trial were reported in June 2022. Here we present the final results of this single-arm, open-label, phase 1 trial, which evaluated the safety and efficacy of satri-cel in patients with CLDN18.2-positive advanced gastrointestinal cancers. This trial included a dose-escalation stage ( n  = 15) and a dose-expansion stage in four different cohorts (total n  = 83): cohort 1, satri-cel monotherapy in 61 patients with standard chemotherapy-refractory gastrointestinal cancers; cohort 2, satri-cel plus anti-PD-1 therapy in 15 patients with standard chemotherapy-refractory gastrointestinal cancers; cohort 3, satri-cel as sequential treatment after first-line therapy in five patients with gastrointestinal cancers; and cohort 4, satri-cel monotherapy in two patients with anti-CLDN18.2 monoclonal antibody-refractory gastric cancer. The primary endpoint was safety; secondary endpoints included efficacy, pharmacokinetics and immunogenicity. A total of 98 patients received satri-cel infusion, among whom 89 were dosed with 2.5 × 10 8 , six with 3.75 × 10 8 and three with 5.0 × 10 8 CAR T cells. Median follow-up was 32.4 months (95% confidence interval (CI): 27.3, 36.5) since apheresis. No dose-limiting toxicities, treatment-related deaths or immune effector cell-associated neurotoxicity syndrome were reported. Cytokine release syndrome occurred in 96.9% of patients, all classified as grade 1–2. Gastric mucosal injuries were identified in eight (8.2%) patients. The overall response rate and disease control rate in all 98 patients were 38.8% and 91.8%, respectively, and the median progression-free survival and overall survival were 4.4 months (95% CI: 3.7, 6.6) and 8.8 months (95% CI: 7.1, 10.2), respectively. Satri-cel demonstrates therapeutic potential with a manageable safety profile in patients with CLDN18.2-positive advanced gastrointestinal cancer. ClinicalTrials.gov identifier: NCT03874897 . In the largest study so far of CAR T cells in patients with solid tumors, autologous CLDN18.2-targeting CAR T cell therapy was well tolerated in patients with advanced CLDN18.2-positive gastrointestinal cancers, with an overall response rate of 42.2% and a disease control rate of 91.1%.

Successfully extending immunotherapies to solid tumors involves addressing several key challenges, importantly the “antigen dilemma”, the expression of a solid tumor target antigen on the normal tissue of tumor origin. Claudin 18.2 (CLDN18.2) has emerged as an important target for upper gastrointestinal (GI) cancer therapies (such as Zolbetuximab, a naked antibody, recently approved; or CT041, a second-generation chimeric antigen receptor (CAR) T cell therapy with promising clinical data). However, GI toxicities are reported from clinical use of both Zolbetuximab and CT041. Here, we describe clinical Zolbetuximab treatment associated cases of gastric erosive lesions. We also demonstrate and characterize on-target/off-tumor gastric toxicity targeting CLDN18.2 in a preclinical mouse model of CT041-scFv derived CAR T cell therapy. By developing CLDN18.2 fully-human VH-only single domain CARs, we demonstrate that on-target/off-tumor toxicity inversely correlates with affinity of the binder, and that a lower affinity CAR may widen the therapeutic window for CLDN18.2 by decreasing on-target/off-tumor toxicity while preserving efficacy. Claudin 18.2 (CLDN18.2) has emerged as a target for gastrointestinal cancer, however, on-target/off-tumor toxicities have been also reported. Here, after reporting evidence of erosive gastritis in patients treated with CLDN18.2 targeted immunotherapies, the authors develop and characterize CLDN18.2 fully-human VH-only single domain CARs, showing that a lower affinity CAR mitigates on-target/off-tumor toxicity while preserving anti-tumor efficacy in gastric cancer models.

Claudin 18.2 (CLDN18.2)-targeted CAR-T cell therapies have shown promising clinical efficacy in gastric cancer. However, early-phase trials have reported gastrointestinal adverse events due to on-target off-tumor recognition of CLDN18.2 in the gastric mucosa. By leveraging shared CLDN18.2 epitopes and expression in humans and mice, we establish an in vivo model that replicates the on-target off-tumor toxicity of CLDN18.2 CAR-T. Our findings confirm that this toxicity is independent of the CAR construct’s design, co-stimulatory domain, and tumor model. Additionally, we demonstrate the utility of this model in testing strategies to mitigate on-target toxicity, such as Boolean-logic AND-gate approaches. Our results offer insights into the use of mouse models that recapitulate on-target off-tumor toxicities, with the caveat that although we are often concerned that models will undercall toxicities in humans, they may also overcall the incidence and severity of toxicities, prematurely discarding promising therapeutic agents from further clinical development. Promising clinical activity of Claudin (CLDN) 18.2-directed CAR-T cell therapy in patients with gastric cancer has been recently reported, however gastrointestinal toxicities have also been described. Here the authors recapitulate the on-target off-tumor toxicity of CLDN18.2-directed CAR-T cells due to gastric mucosa damage in preclinical models, suggesting an AND-gate strategy targeting CLDN18.2 and mesothelin to overcome CAR-T cell toxicity

Expression of claudin-2, a tight junction protein, is highly upregulated during inflammatory bowel disease (IBD) and, due to its association with epithelial permeability, has been postulated to promote inflammation. Notably, claudin-2 has also been implicated in the regulation of intestinal epithelial proliferation. However, precise role of claudin-2 in regulating colonic homeostasis remains unclear. Here, we demonstrate, using Villin-Claudin-2 transgenic mice, that increased colonic claudin-2 expression augments mucosal permeability as well as colon and crypt length. Most notably, despite leaky colon, Cl-2TG mice were significantly protected against experimental colitis. Importantly, claudin-2 expression increased colonocyte proliferation and provided protection against colitis-induced colonocyte death in a PI-3Kinase/Bcl-2-dependent manner. However, Cl-2TG mice also demonstrated marked suppression of colitis-induced increases in immune activation and associated signaling, suggesting immune tolerance. Accordingly, colons from naive Cl-2TG mice harbored significantly increased numbers of regulatory (CD4+Foxp3+) T cells than WT littermates. Furthermore, macrophages isolated from Cl-2TG mouse colon exhibited immune anergy. Importantly, these immunosuppressive changes were associated with increased synthesis of the immunoregulatory cytokine TGF-β by colonic epithelial cells in Cl-2TG mice compared with WT littermates. Taken together, our findings reveal a critical albeit complex role of claudin-2 in intestinal homeostasis by regulating epithelial permeability, inflammation and proliferation and suggest novel therapeutic opportunities.

Cytokine release syndrome (CRS) greatly impacts survival in patients who undergo chimeric antigen receptor (CAR)-T cell therapy, and the identification of its determinants is still challenging. We analysed the impact of systemic immunoinflammatory index (SII) and body composition parameters derived from CT images on the severity of CRS in 45 patients with advanced gastric cancer treated with CLDN18.2-targeted CAR-T cells. The waist circumference, skeletal muscle index (SMI), skeletal muscle density (SMD), subcutaneous fat area (SFA), visceral fat area (VFA) and VFA-to-SFA ratio (VSR) on baseline CT were automatically segmented and calculated using a deep learning-based tool. The relationship between SII, body composition, and CRS severity was investigated by using ROC analysis, univariate and multivariate binary logistic regression. There were no significant differences in SMI, SMD, SFA and waist circumference between patients with CRS grade 1 and 2. CRS grade 2 patients exhibited significantly higher VSR and SII than patients with CRS grade 1 ( P  = 0.003 and 0.012, respectively). ROC analysis showed that the AUCs of VSR and SII for predicting CRS grade were 0.762 (0.620–0.905) and 0.721 (0.563–0.879), respectively. Logistic regression analysis demonstrated that SII > 553 × 10 9 /L and VSR ≥ 0.21 were significantly linked with high grade CRS ( P  = 0.035 and 0.014, respectively). We constructed a two-step scoring CRS prediction model based on VSR and SII, and the AUC of this model achieved 0.802 (0.665–0.939) for predicting high-grade CRS in advanced gastric cancer patients receiving CLDN18.2-targeted CAR-T cell therapy, providing a practical tool for early risk stratification and clinical intervention.

Gastric cancer with peritoneal metastasis (GCPM) carries a poor prognosis, constrained by inadequate drug delivery, systemic toxicity, and an immunosuppressive microenvironment. We developed E3C4, a single mRNA-lipid nanoparticle (LNP) co-encoding EpCAM×CD3 and Claudin18.2×41BB bispecific antibodies (BsAbs), to achieve localized dual-antigen T cell co-activation against GCPM. E3C4 was prepared by co-encapsulating m Ψ-modified mRNAs using ionizable lipids. Functional characterization included surface plasmon resonance (SPR) for binding affinity, T cell-dependent cytotoxicity (TDCC), and 4-1BB reporter assays. In vivo efficacy was evaluated in PBMC-humanized mice bearing subcutaneous or orthotopic NCI-N87 tumors. Immune infiltration and cytokine release were analyzed via flow cytometry and ELISA. Safety was assessed in C57BL/6J mice through acute and repeated-dose toxicity studies. Consequently, E3C4 exhibited optimal particle size and encapsulation efficiency. SPR confirmed high affinity for both BsAbs (KD ~10 M). Synergistic T cell activation achieved 80.9% cytotoxicity in vitro, significantly surpassing EpCAM×CD3 alone (29.1%, P<0.001). In subcutaneous models, 3 μg E3C4 induced 98.5% tumor growth inhibition with enhanced T cell infiltration and granzyme B expression. Intraperitoneal delivery enabled 96.4% tumor-localized expression, yielding superior efficacy over recombinant BsAbs in orthotopic models. E3C4 showed no mortality or cytokine release syndrome, with only transient elevations in IL-6, AST and ALT, as well as a >10% body weight loss that resolved within 2 weeks. The maximum tolerated dose exceeded the therapeutic dose by >200-fold. E3C4 constitutes a localized, synergistic platform that enables dual-antigen T cell co-activation within the peritoneal cavity. This approach maximizes antitumor efficacy while circumventing systemic toxicity, offering a novel immunotherapeutic strategy for GCPM.