Immunosuppressive Tumor Microenvironment Research Articles

The potential contribution of aberrant cathepsin K expression to gastric cancer pathogenesis

The role of cathepsin K (CTSK) expression in the pathogenesis and progression of gastric cancer (GC) remains unclear. Hence, the primary objective of this study is to elucidate the precise expression and biological role of CTSK in GC by employing a combination of bioinformatics analysis and in vitro experiments. Our findings indicated a significant upregulation of CTSK in GC. The bioinformatics analysis revealed that GC patients with a high level of CTSK expression exhibited enrichment of hallmark gene sets associated with angiogenesis, epithelial–mesenchymal transition (EMT), inflammatory response, KRAS signaling up, TNFα signaling via KFκB, IL2-STAT5 signaling, and IL6-JAK-STAT3 signaling. Additionally, these patients demonstrated elevated levels of M2-macrophage infiltration, which was also correlated with a poorer prognosis. The results of in vitro experiments provided confirmation that the over-expression of CTSK leads to an increase in the proliferative and invasive abilities of GC cells. However, further evaluation was necessary to determine the impact of CTSK on the migration capability of these cells. Our findings suggested that CTSK has the potential to facilitate the initiation and progression of GC by augmenting the invasive capacity of GC cells, engaging in tumor-associated EMT, and fostering the establishment of an immunosuppressive tumor microenvironment (TME).

Biointerface‐Engineered Hybrid Nanovesicles for Targeted Reprogramming of Tumor Microenvironment

AbstractThe tumor microenvironment (TME) of typical tumor types such as triple‐negative breast cancer is featured by hypoxia and immunosuppression with abundant tumor‐associated macrophages (TAMs), which also emerge as potential therapeutic targets for antitumor therapy. M1‐like macrophage‐derived exosomes (M1‐Exos) have emerged as a promising tumor therapeutic candidate for their tumor‐targeting and macrophage‐polarization capabilities. However, the limited drug‐loading efficiency and stability of M1‐Exos have hindered their effectiveness in antitumor applications. In this study, we have developed a hybrid nanovesicle by integrating M1‐Exos with AS1411 aptamer‐conjugated liposomes (AApt‐Lips), termed M1E/AALs. The obtained M1E/AALs are loaded with PFTBA and IR780, as P‐Is, to construct P‐I@M1E/AALs for reprogramming TME by alleviating tumor hypoxia and engineering TAMs. P‐I@M1E/AALs‐mediated tumor therapy enhances the in situ generation of reactive oxygen species, repolarizes TAMs toward an antitumor phenotype, and promotes the infiltration of T lymphocytes. The synergistic antitumor therapy based on P‐I@M1E/AALs significantly suppresses tumor growth and prolongs the survival of 4T1 tumor‐bearing mice. By integrating multiple treatment modalities, P‐I@M1E/AALs nanoplatform demonstrates a promising therapeutic approach for overcoming hypoxic and immunosuppressive TME by targeted TAM reprogramming and enhanced tumor photodynamic immunotherapy. This study highlights an innovative TAM‐engineering hybrid nanovesicle platform for the treatment of tumors characterized by hypoxic and immunosuppressive TME.This article is protected by copyright. All rights reserved

Dual depletion of myeloid-derived suppressor cells and tumor cells with self-assembled gemcitabine-celecoxib nano-twin drug for cancer chemoimmunotherapy

Myeloid-derived suppressor cells (MDSCs) have played a significant role in facilitating tumor immune escape and inducing an immunosuppressive tumor microenvironment. Eliminating MDSCs and tumor cells remains a major challenge in cancer immunotherapy. A novel approach has been developed using gemcitabine-celecoxib twin drug-based nano-assembled carrier-free nanoparticles (GEM-CXB NPs) for dual depletion of MDSCs and tumor cells in breast cancer chemoimmunotherapy. The GEM-CXB NPs exhibit prolonged blood circulation, leading to the preferential accumulation and co-release of GEM and CXB in tumors. This promotes synergistic chemotherapeutic activity by the proliferation inhibition and apoptosis induction against 4T1 tumor cells. In addition, it enhances tumor immunogenicity by immunogenic cell death induction and MDSC-induced immunosuppression alleviation through the depletion of MDSCs. These mechanisms synergistically activate the antitumor immune function of cytotoxic T cells and natural killer cells, inhibit the proliferation of regulatory T cells, and promote the M2 to M1 phenotype repolarization of tumor-associated macrophages, considerably enhancing the overall antitumor and anti-metastasis efficacy in BALB/c mice bearing 4T1 tumors. The simplified engineering of GEM-CXB NPs, with their dual depletion strategy targeting immunosuppressive cells and tumor cells, represents an advanced concept in cancer chemoimmunotherapy.Graphical

A dual-enzyme-like photosensitive nanozyme for remodeling the tumor immunosuppressive microenvironment to enhance immunotherapy

In “immune-cold” tumors, the upregulation of immunosuppressive cells and insufficient infiltration of lymphocytes contribute to the resistance against immune therapy. Herein, we have developed a dual-enzyme-like photosensitive nanozyme (PBAF) to remodel the tumor immunosuppressive microenvironment (TIME) and induce the tumor infiltration of cytotoxic T lymphocytes (CTLs). Specifically, PBAF exhibits peroxidase (POD)-like activity and glutathione oxidase (GSHOx)-like activity and can be stimulated by 750 nm laser, promoting oxidative stress at the tumor site. Consequently, this process further leads to the reconstruction of TIME in animal experiments, inducing tumor-associated macrophages (TAMs) toward the immunostimulatory M1 phenotype, eliminating myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs). Simultaneously, PBAF also promotes dendritic cells (DCs) maturation to enhance CTLs infiltration into the tumor. The remodeled TIME and enhanced immune responses by PBAF demonstrate significant post-administration inhibition of recurrence and metastasis in the treatment of malignant tumors.

Nano-Pulse Treatment Overcomes the Immunosuppressive Tumor Microenvironment to Elicit In Situ Vaccination Protection against Breast Cancer.

We previously reported that nano-pulse treatment (NPT), a pulsed power technology, resulted in 4T1-luc mammary tumor elimination and a strong in situ vaccination, thereby completely protecting tumor-free animals against a second live tumor challenge. The mechanism whereby NPT mounts effective antitumor immune responses in the 4T1 breast cancer predominantly immunosuppressive tumor microenvironment (TME) remains unanswered. In this study, orthotopic 4T1 mouse breast tumors were treated with NPT (100 ns, 50 kV/cm, 1000 pulses, 3 Hz). Blood, spleen, draining lymph nodes, and tumors were harvested at 4-h, 8-h, 1-day, 3-day, 7-day, and 3-month post-treatment intervals for the analysis of frequencies, death, and functional markers of various immune cells in addition to the suppressor function of regulatory T cells (Tregs). NPT was verified to elicit strong in situ vaccination (ISV) against breast cancer and promote both acute and long-term T cell memory. NPT abolished immunosuppressive dominance systemically and in the TME by substantially reducing Tregs, myeloid-derived suppressor cells (MDSCs), and tumor-associated macrophages (TAMs). NPT induced apoptosis in Tregs and TAMs. It also functionally diminished the Treg suppression capacity, explained by the downregulation of activation markers, particularly 4-1BB and TGFβ, and a phenotypic shift from predominantly activated (CD44+CD62L-) to naïve (CD44-CD62L+) Tregs. Importantly, NPT selectively induced apoptosis in activated Tregs and spared effector CD4+ and CD8+ T cells. These changes were followed by a concomitant rise in CD8+CD103+ tissue-resident memory T cells and TAM M1 polarization. These findings indicate that NPT effectively switches the TME and secondary lymphatic systems from an immunosuppressive to an immunostimulatory state, allowing cytotoxic T cell function and immune memory formation to eliminate cancer cells and account for the NPT in situ vaccination.

Bisphenol-A in Drinking Water Accelerates Mammary Cancerogenesis and Favors an Immunosuppressive Tumor Microenvironment in BALB-neuT Mice.

Bisphenol-A (BPA), a synthetic compound ubiquitously present in the environment, can act as an endocrine disruptor by binding to both canonical and non-canonical estrogen receptors (ERs). Exposure to BPA has been linked to various cancers, in particular, those arising in hormone-targeted tissues such as the breast. In this study, we evaluated the effect of BPA intake through drinking water on ErbB2/neu-driven cancerogenesis in BALB-neuT mice, transgenic for a mutated ErbB2/neu receptor gene, which reproducibly develop carcinomas in all mammary glands. In this model, BPA accelerated mammary cancerogenesis with an increase in the number of tumors per mouse and a concurrent decrease in tumor-free and overall survival. As assessed by immunohistochemistry, BALB-neuT tumors were ER-negative but expressed high levels of the alternative estrogen receptor GPR30, regardless of BPA exposure. On the other hand, BPA exposure resulted in a marked upregulation of progesterone receptors in preinvasive tumors and of Ki67, CD31, and phosphorylated Akt in invasive tumors. Moreover, based on several infiltration markers of immune cells, BPA favored an immunosuppressive tumor microenvironment. Finally, in vitro cell survival studies performed on a cell line established from a BALB-neuT breast carcinoma confirmed that BPA's impact on cancer progression can be particularly relevant after chronic, low-dose exposure.

Colloidal Hydrogel for Sensitizing Microwave Ablation‐Induced in Situ Tumor Vaccination and Modulating Innate and Adaptive Immunotherapy

AbstractDrawing inspiration from recent advances in microwave ablation (MWA) induced in situ tumor vaccination, a colloidal hydrogel comprising amphoteric gelatin nanoparticles and poly (acrylic acid) (PAA)‐calcium carbonate nanorods (PAA‐CaCO3 NRs) is developed to deliver the microwave‐sensitive agent sodium fluoride (NaF) which can also act as a glycolysis inhibitor in conjunction with the blockade of the T‐cell Ig and ITIM domain (TIGIT), a coinhibitory receptor expressed by both natural killer (NK) cells and T cells. The combination of NaF with microwave (MW) thermal‐dynamic sensitization effectively reversed the acidic and immunosuppressive tumor microenvironment (TME). Moreover, the incorporation of anti‐TIGIT monoclonal antibody (aTIGIT) molecules amplified both the innate and adaptive immune responses by counteracting the exhaustion of NK and effective CD8+ T cells. This augmentation resulted in enhanced tumor elimination and suppression of tumor metastasis and recurrence. Thus, this study underscores the potential of colloidal hydrogel‐sensitized MWA therapy, in conjunction with aTIGIT treatments, as a promising clinical strategy for in situ cancer vaccination.

Dual-Targeted Self-Adjuvant Heterocyclic Lipidoid@Polyester Hybrid Nanovaccines for Boosting Cancer Immunotherapy.

Tumor vaccines have demonstrated a modest response rate, primarily attributed to their inefficient delivery to dendritic cells (DCs), low cross-presentation, DC-intrinsic immunosuppressive signals, and an immunosuppressive tumor microenvironment (TME). Here, draining lymph node (DLN)-targeted and tumor-targeted nanovaccines were proposed to address these limitations, and heterocyclic lipidoid (A18) and polyester (BR647) were synthesized to achieve dual-targeted cancer immunotherapy. Meanwhile, oligo hyaluronic acid (HA) and DMG-PEG2000-Mannose were incorporated to prepare dual-targeted nanovaccines encapsulated with STAT3 siRNA and model antigens. The nanovaccines were designed to target the DLN and the tumor, facilitating the delivery of cargo into the cytoplasm. These dual-targeted nanovaccines improved antigen presentation and DC maturation, activated the stimulator of interferon genes (STING) pathway, enhanced the pro-apoptotic effect, and stimulated antitumor immune responses. Additionally, these dual-targeted nanovaccines overcame immunosuppressive TME, reduced immunosuppressive cells, and promoted the polarization of tumor-associated neutrophils from N2 to N1. Among the four dual-targeted nanovaccines that induced robust antitumor responses, the heterocyclic lipidoid@polyester hybrid nanovaccines (MALO@HBNS) demonstrated the most promising results. Furthermore, a combination strategy involving MALO@HBNS and an anti-PD-L1 antibody exhibited an immensely powerful anticancer role. This work introduced a dual-targeted nanovaccine platform for antitumor treatment, suggesting its potential combination with an immune checkpoint blockade as a comprehensive anticancer strategy.

Necroptosis-Mediated Synergistic Photodynamic and Glutamine-Metabolic Therapy Enabled by a Biomimetic Targeting Nanosystem for Cholangiocarcinoma.

Targeted delivery of glutamine metabolism inhibitors holds promise for cholangiocarcinoma therapy, yet effective delivery vehicles remain a challenge. This study reports the development of a biomimetic nanosystem, termed R-CM@MSN@BC, integrating mesoporous organosilicon nanoparticles with reactive oxygen species-responsive diselenide bonds for controlled release of the glutamine metabolism inhibitor bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl) ethyl sulfide (BPTES) and the photosensitizer Ce6. Erythrocyte membrane coating, engineered with Arg-Gly-Asp (RGD) peptides, not only enhanced biocompatibility but also improved tumor targeting and tissue penetration. Upon laser irradiation, R-CM@MSN@BC executed both photodynamic and glutamine-metabolic therapies, inducing necroptosis in tumor cells and triggering significant immunogenic cell death. Time-of-flight mass cytometry analysis revealed that R-CM@MSN@BC can remodel the immunosuppressive tumor microenvironment by polarizing M1-type macrophages, reducing infiltration of M2-type and CX3CR1+ macrophages, and decreasing T cell exhaustion, thereby increasing the effectiveness of anti-programmed cell death ligand 1 immunotherapy. This strategy proposed in this study presents a viable and promising approach for the treatment of cholangiocarcinoma.

Why does circadian timing of administration matter for immune checkpoint inhibitors' efficacy?

Tolerability and antitumour efficacy of chemotherapy and radiation therapy can vary largely according to their time of administration along the 24-h time scale, due to the moderation of their molecular and cellular mechanisms by circadian rhythms. Recent clinical data have highlighted a striking role of dosing time for cancer immunotherapy, thus calling for a critical evaluation. Here, we review the clinical data and we analyse the mechanisms through which circadian rhythms can influence outcomes on ICI therapies. We examine how circadian rhythm disorders can affect tumour immune microenvironment, as a main mechanism linking the circadian clock to the 24-h cycles in ICIs antitumour efficacy. Real-life data from 18 retrospective studies have revealed that early time-of-day (ToD) infusion of immune checkpoint inhibitors (ICIs) could enhance progression-free and/or overall survival up to fourfold compared to late ToD dosing. The studies involved a total of 3250 patients with metastatic melanoma, lung, kidney, bladder, oesophageal, stomach or liver cancer from 9 countries. Such large and consistent differences in ToD effects on outcomes could only result from a previously ignored robust chronobiological mechanism. The circadian timing system coordinates cellular, tissue and whole-body physiology along the 24-h timescale. Circadian rhythms are generated at the cellular level by a molecular clock system that involves 15 specific clock genes. The disruption of circadian rhythms can trigger or accelerate carcinogenesis, and contribute to cancer treatment failure, possibly through tumour immune evasion resulting from immunosuppressive tumour microenvironment. Such emerging understanding of circadian rhythms regulation of antitumour immunity now calls for randomised clinical trials of ICIs timing to establish recommendations for personalised chrono-immunotherapies with current and forthcoming drugs.

DYRK1B blockade promotes tumoricidal macrophage activity in pancreatic cancer

ObjectiveHighly malignant pancreatic ductal adenocarcinoma (PDAC) is characterised by an abundant immunosuppressive and fibrotic tumour microenvironment (TME). Future therapeutic attempts will therefore demand the targeting of tumours and stromal compartments...

Updated results from first-in-human phase 1 dose-escalation trial of TAK-102, a GPC3-targeted armored CAR T cells, in patients with advanced solid tumors.

2543 Background: Glypican 3 (GPC3) is a member of the glypican family of heparan sulfate proteoglycans that are attached to the cell surface by a glycosylphosphatidylinositol anchor. High GPC3 expression rates are reported in numerous cancer types with a high unmet medical need, including hepatocellular carcinoma (HCC). TAK-102 is a GPC3-targeted autologous chimeric antigen receptor T cell (CAR-T) immunotherapy armored with IL-7 and CCL19. The addition of IL-7 and CCL19 to the construct was designed to support the expansion of memory subsets and persistence of CAR-T cells. We hypothesized TAK-102 would help overcome the challenges associated with an immunosuppressive tumor microenvironment that limit the activity of nonarmored CAR-T therapies in solid tumors. Methods: The first-in-human, Phase 1 dose escalation study evaluated TAK-102 in patients (pts) with GPC3-expressing solid tumors who were refractory or intolerant to standard treatments. TAK-102 was administered via a single infusion to 3 dose cohorts after lymphodepleting chemotherapy (LDC; consisting of fludarabine and cyclophosphamide): dose level (DL) 1 (starting cohort), 1x107 CAR+ cells/body; DL2, 1x108 CAR+ cells/body; DL3, 5x108 CAR+ cells/body. Objectives included evaluation of safety, dose-limiting toxicity (DLT), recommended phase 2 dose, cellular kinetic (CK) parameters, tumor markers, cytokine/chemokine and antitumor activity based on RECIST 1.1. Results: Eleven pts were enrolled and infused TAK-102 (DL1: 3 pts, DL2: 3 pts, DL3: 5 pts): 1 gastric neuroendocrine carcinoma, 2 liposarcoma, 8 HCC. Five pts achieved stable disease (SD), HCC (GPC3 H-Score: 36) . In patients achieving SD, the greatest reduction in tumor size was 26.4%. No DLTs or neurotoxicity were observed. Six pts experienced cytokine release syndrome (Grade1: 5 pts, Grade2: 1 pt); all cases were manageable. AFP was measured as a tumor marker for HCC. Among 8 pts with HCC, 4 had SD after treatment with TAK-102 and 3 showed a decrease or stabilization of AFP levels corresponding to their clinical status. CK profiles for pts were assessed by flow cytometry and qPCR-based assays. Overall, there was improvement in TAK-102 exposure (Cmax, AUC) when escalating from DL1 to DL2. There was a slight decrease in Tmax from DL2 to DL3. Homeostatic cytokine (IL-7) spiked post-LDC and showed no further increase after TAK-102 infusion across all the DLs. There was dose-dependency observed in peak CCL19, IFN-γ and IL-6 levels. Conclusions: TAK-102, an armored CAR-T, is well tolerated and has a manageable safety profile with some early signs of anti-tumor activity. For CK, TAK-102 exposure (Cmax, AUC) showed improvement from DL1 to DL2, and slight decrease in Tmax from DL2 to DL3. Dose-dependency was observed in peak CCL19, IFN-γ and IL-6 levels, which may point towards increased signal of activity from DL1 to DL3. Clinical trial information: NCT04405778 .

Enhanced anti-ovarian cancer efficacy with MSLN-chimeric antigen receptor T cells secreting anti-CD39 antibody.

e17553 Background: The effectiveness of chimeric antigen receptor (CAR) T cell therapy directed at mesothelin (MSLN) in solid tumors, such as ovarian cancer, is hindered by the immunosuppressive tumor microenvironment (TME), where adenosine plays a crucial role in impairing CAR-T cell function. Preclinical and clinical studies have demonstrated that targeting CD39, a pivotal enzyme catalyzing the conversion of extracellular ATP into adenosine, yields significant antitumor effects. Therefore, combining MSLN CAR-T with an anti-CD39 antibody emerges as a potential therapeutic strategy against cancer. Methods: We have previously designed OriA631, an antibody antagonist targeting CD39 in VHH format. Our preclinical investigation has highlighted the outstanding potential of OriA631, showcasing superior performance in binding affinity, effective inhibition of CD39 enzyme activity, and remarkable in vivo high anti-tumor efficacy. Subsequently, we undertook further engineering of MSLN CAR-T cells to secrete the VHH component of OriA631 (MSLN CAR-T-CD39-VHH) and systematically assessed its antitumor effects in NSG mice. Results: Our data reveals that MSLN CAR-T cells exhibit a significant upregulation of CD39 upon activation by ovarian cancer cells in both in vitro and in the tumor microenvironment (TME). To assess the combined effect of MSLN CAR-T with anti-CD39, B-NDG mice were subcutaneously inoculated with 3x10^6 ovarian cancer cells (SKOV3-MSLNhi-CD39hi). Subsequently, different T cells (1x10^7 cells/mouse) were injected when the tumor reached around 80 mm³, and the groups were divided into Mock T, MSLN CAR-T, MSLN CAR-T-CD39-VHH, and MSLN CAR-T in combination with locally injected CD39 Ab (OriA631). The data demonstrated that MSLN CAR-T inhibited tumor growth from approximately 1000mm³ (Mock T group) to 300mm³ at day 30 relative to T cell injection. Tumors in the MSLN CAR-T in combination with OriA631 group were around 100mm³, suggesting a significant combination anti-tumor efficacy of MSLN CAR-T in conjunction with CD39 targeting. Furthermore, MSLN CAR-T-CD39-VHH, where MSLN CAR-T cells secrete the VHH component of OriA631, completely eliminated the tumor at day 18 with no relapse during the experimental period. This result underscores the superior anti-tumor efficacy of MSLN CAR-T-CD39-VHH, with the high level of VHH component of CD39 Ab observed in the TME. Importantly, the low or undetectable level of VHH component of CD39 Ab in the serum also indicates the safety of the product. Conclusions: Our study introduces the innovative therapeutic agent MSLN CAR-T-CD39-VHH, showcasing superior anti-tumor efficacy and the potential for reduced antibody-associated side effects. These findings strongly endorse the application of MSLN CAR-T-CD39-VHH as a promising and impactful therapeutic approach for the treatment of ovarian cancer.

Genomic characteristics of tumour necrosis in lung squamous cell carcinoma.

e20030 Background: Tumor necrosis and cavity on enhanced chest CT are common hallmarks of lung squamous cell carcinoma (LUSC). However, the genetic characteristics of necrosis on CT scan remain unclear. This study aims to elucidate the genetic landscape of LUSC with tumor necrosis. Methods: We implemented transcriptome and whole-exome sequencing to analyze early postoperative LUSC specimens. They were classified into necrosis and non-necrosis group based on preoperative enhanced chest CT. Subsequently, the genomic landscape between the two groups were compared. To substantiate our findings, we further employed immunohistochemistry and analysis of a clinical cohort as comprehensive methods of validation. Results: In study cohort (65 samples), the necrosis group (n = 37) showed a higher number and length of copy number variations (CNVs) and elevated Genomic Instability Index (GII) compared to the non-necrosis group (n = 28). Transcriptome sequencing revealed increased hypoxic hallmarks and activation of 11 fundamental metabolic pathways in the necrosis group. Endothelial cells were observably fewer, but matrix remodeling score was higher in the necrosis group. Here, the decreased activity of several immune-related pathways, such as antigen processing and presentation, natural killer cell-mediated cytotoxicity, etc, were notably suppressed in the necrosis group. Immunohistochemistry indicated that the expressions of hypoxy-related genes (HIF-1, NDRG1), proliferation-related genes (ki-67) and angiogenesis related genes (CD31) in necrosis group were significantly higher than those in non-necrosis group. In the clinical validation cohort, we enrolled 538 advanced LUSC patients from 25 medical centers receiving systemic treatment, categorized into chemotherapy (n = 270) and ICIs (n = 268) groups. A notable difference in progression-free survival (PFS) was observed in the ICIs group, with patients without tumor necrosis or cavity exhibiting significantly longer PFS (8.7 vs. 6.5 months; HR 0.67; 95% CI 0.42–0.63; p < 0.001). Multivariate Cox analysis identified necrosis or cavity as an independent predictor of reduced PFS (HR 0.68; 95% CI, 0.51-0.9; p = 0.007). Conclusions: LUSC with necrosis is distinguished by increased genomic instability, hypoxia, enhanced tumor proliferation, matrix remodeling, and an immunosuppressive tumor microenvironment. Baseline chest CT findings of tumor necrosis or cavities may serve as negative predictors for the efficacy of ICIs treatment in LUSC.

A phase I study to evaluate the safety and tolerability of JCXH-211 (a self-replicating mRNA encoding IL-12) intratumoral injection in patients with malignant solid tumors: Results from the phase Ia dose escalation.

2539 Background: Although interleukin (IL)-12 demonstrated strong preclinical antitumor activity and potent immune-stimulating potentials clinically, systemic administration of IL-12 protein was associated with poor clinical safety profiles. IL-12 functions locally through paracrine and autocrine mechanisms, thus maximizing local concentration of IL-12 in the tumors is important. JCXH-211 is a self-replicating ribonucleic acid (srRNA) encoding human IL-12 encapsulated in lipid nanoparticles. Intratumoral (IT) administration of JCXH-211 is expected to produce the desired spatiotemporal distribution of IL-12 in the cancer lesions. srRNA features enhanced translatability in immunosuppressed tumor microenvironment (TME) than in normal tissues further limiting off-target toxicity. Additionally, the self-replicating nature of JCXH-211 engages multiple immune effector mechanisms and helps inflame TME. We present interim results of the dose escalation part of JCXH-211 IT injection as monotherapy in patients (pts) with malignant solid tumors. Enrollment for the 100 μg cohort is ongoing and updated data will be presented at the meeting. Methods: Pts with advanced solid tumors suitable for IT injection are enrolled. JCXH-211 at 5, 25, 50, and 100 μg are given every 4 weeks (Q4W). Dose Limiting Toxicities (DLT) are monitored for 28 days after 1st dose. Dose escalation follows “3+3” principle. Tumor assessment is performed Q6W using RECIST v1.1. Results: Ten pts with advanced cancers have been enrolled in 5 μg, 25 μg, and 50 μg cohorts: 3 melanoma (MEL), 3 breast cancer (BC), 2 head and neck cancer (HNSC), 1 nasopharyngeal cancer and 1 sarcoma. Nine pts completed DLT observation without DLT; 1 pt withdrew early. No drug-related SAE was reported. Most drug-related AEs were Grade 1/2 and recovered quickly. Only 1 pt in the 25 μg cohort reported 3 Grade 3 AEs possibly related to drug: lymphocytopenia (2 events) and anemia. Seven pts completed at least one post-dose tumor assessment. Three pts experienced shrinkages of the treated lesions by 13.0%, 33.3% and 43.0%, corresponding to BC, HNSC and MEL in the 5 μg, 25 μg, and 50 μg cohorts, respectively. Tumor shrinkage of 31% was also observed in a non-injected lesion of an HNSC pt receiving 25μg JCXH-211 suggesting abscopal effects. Histopathological analysis of the treated lesions demonstrated increased T and NK cell infiltration (as high as 138 folds) post study drug administration. Conclusions: JCXH-211 IT administration with doses of 5μg, 25μg, 50μg Q4W demonstrated good safety profile. Antitumor activities were observed in the heavily pretreated late-stage pts. Significant increases of T and NK cell infiltration were observed. These data support continued evaluation of JCXH-211 IT. Clinical trial information: NCT05727839 .

A phase 2 study of ipatasertib in combination with pembrolizumab for first-line treatment of recurrent or metastatic squamous cell cancer of the head and neck.

TPS6117 Background: Single agent pembrolizumab in relapsed / metastatic head and neck squamous cell carcinoma (R/M HNSCC) has an estimated ORR of 19% and median OS of 13.6 months. There are several factors which may influence which patients respond to antibodies targeting the PD-1 axis. Regulatory T cells (Tregs) play a significant role in an immunosuppressive tumor microenvironment. Anti-PD-1 antibodies induce Treg activation in part through AKT pathway activation, which may contribute to low response rates to checkpoint inhibitor therapy. AKT blockade selectively inhibits the proliferation of human Tregs. Additionally, inhibition of the PI3K-AKT-mTOR pathway limits myeloid-derived suppressor cells (MDSC) infiltration and differentiation, and boosts CD8+ T cell memory and effector function. Ipatasertib is an oral highly selective small-molecule inhibitor of all three isoforms of AKT. This phase 2 trial is designed to compare progression-free survival (PFS) in first line R/M, HNSCC patients treated with the combination ipatasertib and pembrolizumab versus pembrolizumab monotherapy treatment. Methods: In this open-label randomized phase 2 multicenter trial, patients with R/M HNSCC are treated with pembrolizumab 200mg on day 1 +/- ipatasertib 400mg QD days 1-14 of 21-day cycles. Patients must have PD-L1 CPS score ³ 1, have measurable disease per RECIST 1.1, and consent to on-treatment biopsy. Patients will be excluded if they have received prior systemic therapy for R/M HNSCC, cannot swallow a pill, or require insulin for diabetes. The primary objective is to compare the PFS between the two arms. We will estimate the relative hazard ratio associated with ipatasertib plus pembrolizumab compared to pembrolizumab alone using the Cox Model where randomized treatment assignment is the only variable in the model. Secondary objectives include ORR, safety and tolerability of the combination, and changes in tumor immune cell infiltration, AKT signaling, and changes in peripheral blood immune cells. Ultimately, a total of 48 patients will be enrolled, with 24 patients in each cohort. To date, a total of 22 patients have been enrolled from 15 sites. Accrual is ongoing (NCT05172258). Clinical trial information: NCT05172258 .

Phase I, open-label, dose-escalation trial investigating the safety and efficacy of oncolytic virus BI 1821736 in patients with advanced solid tumors.

TPS2688 Background: Despite some advances, the need for novel anti-cancer therapies remains high in patients with advanced solid tumors. Although immunotherapy with checkpoint inhibitors is the preferred treatment for several cancer types, a proportion of patients will have non-responsive tumors or develop resistance. Oncolytic viruses have potential as novel immunotherapies, due to their tumor-selectivity and ability to stimulate a systemic anti-tumor immune response. BI 1821736 is a genetically engineered pseudotype variant of VSV-GP encoding an immune-stimulatory cargo. The VSV-GP backbone is a recombinant chimeric vesicular stomatitis virus modified to replace the innate neurotropic G glycoprotein with the non-neurotropic GP glycoprotein from the lymphocytic choriomeningitis virus. BI 1821736 selectively replicates and lyses cells with defective interferon signaling, which is seen particularly in cancer cells. The immune-stimulating cargo leads to T-cell priming and reactivation within the immunosuppressed tumor microenvironment. Preclinical efficacy, toxicology, and environmental safety results support BI 1821736 administration in humans. Methods: 1467-0001 (NCT05839600) is a Phase I, open-label, dose-escalation study evaluating the safety and early efficacy of BI 1821736 in patients with advanced solid tumors. The study is enrolling adult patients who have exhausted available treatment options, with an Eastern Cooperative Oncology Group Performance Status of 0 or 1, ≥1 lesion amenable to biopsy, and adequate organ function. Patients with brain metastases are excluded unless they have completed brain radiotherapy and are asymptomatic. Patients will receive escalating doses of intravenous BI 1821736 for up to 3 months. Dose escalation will be guided by a Bayesian 2-parameter logistic regression model with overdose control (BLRM-EWOC). The primary objective is to determine the maximum tolerated dose (MTD) and/or recommended Phase II dose based on occurrence of dose-limiting toxicities (DLTs) during the MTD evaluation period of the first treatment cycle (Cycle 1; 21 days). Other safety endpoints include the occurrence of DLTs and adverse events during the treatment period. Further objectives include the assessment of BI 1821736 preliminary efficacy, pharmacokinetics, immunogenicity, shedding, and biomarkers. Patients are being recruited from approximately 10 sites across North America and Europe. Enrollment began in May 2023. A total of six patients have received BI 1821736 as of January 29, 2024. Patients are currently being enrolled to dose level 2. Clinical trial information: NCT05839600 .

Overall survival after treatment with CAN-2409 plus valacyclovir in combination with continued ICI in patients with stage III/IV NSCLC with an inadequate response to ICI.

8634 Background: Patients with unresectable non-small cell lung cancer (NSCLC) with an inadequate response to immune checkpoint inhibitors (ICI) have limited therapeutic options and expected median overall survival (mOS) of 11.6 to 14.5m (PMID: 35658002 ). The immunosuppressive tumor microenvironment and the lack of a specific T cell response underpin inadequate clinical response. CAN-2409 is a replication-defective adenovirus encoding the HSV-tk gene. Transduced cells activate orally delivered valacyclovir, resulting in immunogenic cell death, and in situ immunization against the patient’s tumor antigens, eliciting a specific immune response against the injected tumor and uninjected metastases. Methods: NCT04495153 is an open-label, phase 2 clinical trial of CAN-2409 + valacyclovir in combination with continued ICI in patients with non-resectable, stage III/IV NSCLC, refractory or resistant to anti-PD-(L)1. Patients were enrolled in 2 cohorts (C) depending on disease status at enrolment: C1, stable disease or C2, progressive disease. Two doses of CAN-2409 (5x1011vp) were given 5-7w apart via bronchoscopic or percutaneous injection into lung tumor, disease-positive lymph node, or peripheral metastasis, each followed by oral prodrug. Patients were assessed for safety, immunologic biomarkers, and OS. Results: As of 16Jan2024, 73 patients were treated (safety population: ≥1 dose of CAN-2409) and 44 were evaluable per protocol (received 2 doses of CAN-2409+ valacyclovir and 12-week CT scan). Baseline treated pt median age was 67 [43-88] yrs, 44% female, 68% on aPD(L)1 alone and 32% aPD(L)1 + pemetrexed regimen. We observed no dose-limiting toxicities or ≥grade 4 treatment-related AEs. mOS of the evaluable population was estimated as 22.0m (95% CI: 14.3m, NA; median follow up (mFU) time of 18.2m). In C2 (n = 38) mOS was 20.6 (mFU 19.2.m) and in C1 (n = 6) was N.A. (mFU 15.2m). mOS in the safety population (n = 73) was 14.3.m (mFU16.8m). 64% of evaluable patients had systemic clinical response with shrinkage of both injected and uninjected lesions. We found a significant correlation between increases in T cell populations after the second injection of CAN-2409 (circulating memory and effector memory CD4+ and CD8+T cells, CD4+ Ki67+IFNg+ and CD4+granzymeB+ T cells, CD8+granzymeB+Ki67+ T cells, T regulatory cells) and subsequent OS (R2 between 0.181 and 0.354 and p = 0.043 and 0.004). Conclusions: Experimental treatment with CAN-2409+valacyclovir in NSCLC pts following an inadequate response to ICI is well tolerated and results in the induction of a cytotoxic and memory circulating T cell response associated with shrinkage of injected and uninjected lesions and a raised tail of the survival curve. mOS of the evaluable population was estimated as 22.0m, markedly longer than the expected mOS of 11.6-14.5m. Clinical trial information: NCT04495153 .

Phase I clinical study of FC084CSA, a high selective AXL kinase inhibitor that ameliorates tumor microenvironment and augments the effectivity of immunotherapy.

e15116 Background: NSCLC patients with STK11 gene mutations could not benefit from immunotherapy, according to the data of multiple clinical trials. This is associated with immunosuppressive tumor microenvironment (TME) due to elevated AXL expression, and deficiency in pro-inflammatory cytokines and effector T cells. AXL inhibitor bemcentinib (formerly BGB324) has been found to improve the effectiveness of immunotherapy of immune checkpoint inhibitors. FC084CSA is a high selective AXL inhibitor. Methods: This is an ongoing first-in-human, phase I study of FC084CSA in patients with advanced solid tumors. The primary objective is to evaluate the safety and tolerability of FC084CSA. The secondary objectives include preliminary efficacy and pharmacokinetics. Results: As of January 10th, 2024, 9 patients with a median age of 60 years (44-73) were enrolled in 4 different dose levels: 100mg QD, 200mg QD, 400mg QD and 600mg QD. All patients had ≥ 2 prior lines of prior therapy. No dosing-limiting toxicities were observed. 8 (88.9%) patients experienced treatment-related adverse events (TRAEs). Most TRAEs were grade 1 or 2 and only one grade 3 TRAE was observed. The most common TRAEs (≥20%) included increased blood lactate dehydrogenase (44.4%), elevated gamma-glutamyl transferase (33.3%), proteinuria (33.3%), anemia (33.3%), increased aspartate aminotransferase (22.2%), weight loss (22.2%), increased blood creatinine (22.2%) and vomiting (22.2%). A total of 8 patients had at least 1 post-baseline tumor assessment. Objective response rate (ORR) was 0% and disease control rate (DCR) was 62.5% (5/8). Conclusions: FC084CSA was well tolerated in patients with previously heavily treated solid tumors. Clinical trial information: NCT06231550 .

Intravenous delivery of STING agonists using acid-sensitive polycationic polymer-modified lipid nanoparticles for enhanced tumor immunotherapy

Although cancer immunotherapy has made great strides in the clinic, it is still hindered by the tumor immunosuppressive microenvironment (TIME). The stimulator of interferon genes (STING) pathway which can modulate TIME effectively has emerged as a promising therapeutic recently. However, the delivery of most STING agonists, specifically cyclic dinucleotides (CDNs), is performed intratumorally due to their insufficient pharmacological properties, such as weak permeability across cell membranes and vulnerability to nuclease degradation. To expand the clinical applicability of CDNs, a novel pH-sensitive polycationic polymer-modified lipid nanoparticle (LNP-B) system was developed for intravenous delivery of CDNs. LNP-B significantly extended the circulation of CDNs and enhanced the accumulation of CDNs within the tumor, spleen, and tumor-draining lymph nodes compared with free CDNs thereby triggering the STING pathway of dendritic cells and repolarizing pro-tumor macrophages. These events subsequently gave rise to potent anti-tumor immune reactions and substantial inhibition of tumors in CT26 colon cancer-bearing mouse models. In addition, due to the acid-sensitive property of the polycationic polymer, the delivery system of LNP-B was more biocompatible and safer compared with lipid nanoparticles formulated with an indissociable cationic DOTAP (LNP-D). These findings suggest that LNP-B has great potential in the intravenous delivery of CDNs for tumor immunotherapy.