Reprogramming tumor immune microenvironment by milbemycin oxime results in pancreatic tumor growth suppression and enhanced anti-PD-1 efficacy.

Pancreatic ductal adenocarcinoma (PDAC) has a survival rate of 12%, and multiple clinical trials testing anti-PD-1 therapies against PDAC have failed, suggesting a need for a novel therapeutic strategy. In this study, we evaluated the potential of milbemycin oxime (MBO), an antiparasitic compound, as an immunomodulatory agent in PDAC. Our results show that MBO inhibited the growth of multiple PDAC cell lines by inducing apoptosis. In vivo studies showed that the oral administration of 5 mg/kg MBO inhibited PDAC tumor growth in both subcutaneous and orthotopic models by 49% and 56%, respectively. Additionally, MBO treatment significantly increased the survival of tumor-bearing mice by 27 days as compared to the control group. Interestingly, tumors from MBO-treated mice had increased infiltration of CD8+ T cells. Notably, depletion of CD8+ T cells significantly reduced the anti-tumor efficacy of MBO in mice. Furthermore, MBO significantly augmented the efficacy of anti-PD-1 therapy, and the combination treatment resulted in a greater proportion of active cytotoxic T cells within the tumor microenvironment. MBO was safe and well tolerated in all our preclinical toxicological studies. Overall, our study provides a new direction for the use of MBO against PDAC and highlights the potential of repurposing MBO for enhancing anti-PD-1 immunotherapy.

The Prognostic Value of CD39 as a Marker of Tumor-Specific T Cells in Triple-Negative Breast Cancer in Asian Women.

Triple-negative breast cancer (TNBC) has a poor prognosis with limited therapeutic options available for affected patients. Efforts are ongoing to identify surrogate markers for tumor-specific CD8+ T cells that can predict the response to immune checkpoint inhibitor (ICI) therapies, such as programmed cell death protein 1 or programmed cell death ligand-1 blockade. We have previously identified tumor-specific CD39+CD8+ T cells in non-small cell lung cancer that might help predict patient responses to programmed cell death protein 1 or programmed cell death ligand-1 blockade. Based on this finding, we conducted a comparative interrogation of TNBC in an Asian cohort to evaluate the potential of CD39 as a surrogate marker of tumor-specific CD8+ T cells. Using ICI-treated TNBC mouse models (n = 24), flow cytometric analyses of peripheral blood mononuclear cells and tumor-infiltrating lymphocytes revealed that >99% of tumor-specific CD8+ T cells also expressed CD39. To investigate the relationship between CD39+CD8+ T-cell density and CD39 expression with disease prognosis, we performed multiplex immunohistochemistry staining on treatment-naive human TNBC tissues (n = 315). We saw that the proportion of CD39+CD8+ T cells in human TNBC tumors correlated with improved overall survival, as did the densities of other CD39+ immune cell infiltrates, such as CD39+CD68+ macrophages. Finally, increased CD39 expression on CD8+ T cells was also found to predict the response to ICI therapy (pembrolizumab) in a separate cohort of 11 TNBC patients. These findings support the potential of CD39+CD8+ T-cell density as a prognostic factor in Asian TNBC patients.

Mutation status of the KMT2 family associated with immune checkpoint inhibitors (ICIs) therapy and implicating diverse tumor microenvironments.

Mounting evidence suggests a strong association between tumor immunity and epigenetic regulation. The histone-lysine N-methyltransferase 2 (KMT2) family plays a crucial role in the methylation of histone H3 at lysine 4. By influencing chromatin structure and DNA accessibility, this modification serves as a key regulator of tumor progression and immune tolerance across various tumors. These findings highlight the potential significance of the KMT2 family in determining response to immune checkpoint inhibitor (ICI) therapy, which warrants further exploration. In this study, we integrated four ICI-treated cohorts (n = 2069) across 10 cancer types and The Cancer Genome Atlas pan-cancer cohort and conducted a comprehensive clinical and bioinformatic analysis. Our study indicated that patients with KMT2 family gene mutations benefited more from ICI therapy in terms of overall survival (P < 0.001, hazard ratio [HR] = 0.733 [95% confidence interval (CI): 0.632-0.850]), progression-free survival (P = 0.002, HR = 0.669 [95% CI: 0.518-0.864]), durable clinical benefit (P < 0.001, 54.1% vs. 32.6%), and objective response rate (P < 0.001, 40.6% vs. 22.0%). Through a comprehensive analysis of the tumor microenvironment across different KMT2 mutation statuses, we observed that tumors harboring the KMT2 mutation exhibited enhanced immunogenicity, increased infiltration of immune cells, and higher levels of immune cell cytotoxicity, suggesting a propensity towards a "hot tumor" phenotype. Therefore, our study indicates a potential association between KMT2 mutations and a more favorable response to ICI therapy and implicates different tumor microenvironments associated with ICI therapy response.

A phase II study of cabozantinib and pembrolizumab in advanced gastric/gastroesophageal adenocarcinomas resistant or refractory to immune checkpoint inhibitors.

BACKGROUND: Most patients with metastatic gastroesophageal adenocarcinoma (mGEA) progress on immune checkpoint inhibitors (ICIs). Novel approaches to overcome resistance to ICI in mGEA are needed. Cabozantinib is a multi-tyrosine kinase inhibitor thought to enhance the immunomodulatory effects of ICI. This study evaluated the combination of cabozantinib and pembrolizumab in ICI refractory or resistant mGEA. METHODS: Investigator-initiated, single-arm, single institution, and phase II study in patients with mGEA. Patients had progressed on ICI and/or had PD-L1 CPS score ≤10%. Cabozantinib dose was 40 mg p.o. daily on days 1-21 of a 21-day cycle, with pembrolizumab 200 mg i.v. on day 1. The primary endpoint was progression-free survival at 6 months (PFS-6). RESULTS: Twenty-seven patients were enrolled. Median age 58 years (24-87), female (n = 14), ECOG 0/1 = 13/14, GC/GEJ = 16/11, and non-Hispanic White/Hispanic/Asian = 12/8/7. The primary endpoint was met. After a median follow-up of 31.4 months (range 3.3-42.5), PFS-6 was 22.2% (95% CI 9.0-39.0). The median PFS and OS are 2.3 months (95% CI 1.7-4.1) and 5.5 months (3.1-14.0), respectively. The most common mutations were TP53 (78.3%) and CDH1/PIK3CA/CTNNB1 (17.4% each). The most common grade (G) treatment-related adverse events (TRAE) were diarrhea (25.9%), fatigue (18.5%), hypertension, and muscle cramps (14.8% each). G3-4 TRAE were seen in n = 3 patients (hypertension, thromboembolic event, esophageal perforation; each n = 1). No G5 was observed. CONCLUSIONS: The addition of cabozantinib to pembrolizumab shows clinical benefit in ICI-resistant or refractory mGEA with a tolerable safety profile. (ClinicalTrials.gov Identifier: NCT04164979. IRB Approved: UCI 18-124, University of California Irvine IRB#20195426.).

An analysis pipeline for understanding 6-thioguanine effects on a mouse tumour genome.

Mouse tumour models are extensively used as a pre-clinical research tool in the field of oncology, playing an important role in anticancer drugs discovery. Accordingly, in cancer genomics research, the demand for next-generation sequencing (NGS) is increasing, and consequently, the need for data analysis pipelines is likewise growing. Most NGS data analysis solutions to date do not support mouse data or require highly specific configuration for their use. Here, we present a genome analysis pipeline for mouse tumour NGS data including the whole-genome sequence (WGS) data analysis flow for somatic variant discovery, and the RNA-seq data flow for differential expression, functional analysis and neoantigen prediction. The pipeline is based on standards and best practices and integrates mouse genome references and annotations. In a recent study, the pipeline was applied to demonstrate the efficacy of low dose 6-thioguanine (6TG) treatment on low-mutation melanoma in a pre-clinical mouse model. Here, we further this study and describe in detail the pipeline and the results obtained in terms of tumour mutational burden (TMB) and number of predicted neoantigens, and correlate these with 6TG effects on tumour volume. Our pipeline was expanded to include a neoantigen analysis, resulting in neopeptide prediction and MHC class I antigen presentation evaluation. We observed that the number of predicted neoepitopes were more accurate indicators of tumour immune control than TMB. In conclusion, this study demonstrates the usability of the proposed pipeline, and suggests it could be an essential robust genome analysis platform for future mouse genomic analysis.

Targeting tumorous Circ-E-Cadherinencoded C-E-Cad inhibits the recruitment and function of breast cancer-associated myeloid-derived suppressor cells.

We previously demonstrated that the C-E-cad protein encoded by circ-E-cadherin promotes the self-renewal of glioma stem cells. The expression pattern of C-E-cad in breast cancer and its potential function in the tumor microenvironment are unclear. The expression of circ-E-cadherin and C-E-cad was detected in breast cancer specimens. The influence of C-E-cad expression on MDSCs was assessed using FACS and in vivo tumorigenesis experiments. The synergistic effect of anti-C-E-cad and anti-PD-1 antibodies was validated in vivo. circ-E-cadherin and the encoded protein C-E-cad were found to be upregulated in breast cancer vs. normal samples. C-E-cad promotes the recruitment of MDSCs, especially PMN-MDSCs. C-E-cad activates EGFR signaling in tumor cells and promotes the transcription of CXCL8; moreover, C-E-cad binds to MDSCs and maintains glycolysis in PMN-MDSCs. Targeting C-E-cad enhanced anti-PD-1 efficiency. Our data suggested that C-E-cad is markedly overexpressed in breast cancer and promotes MDSC recruitment and survival. Targeting C-E-cad increases the efficacy of immune checkpoint inhibitor therapy.

Current Insights into CAR T-Cell-Based Therapies for Myelodysplastic Syndrome.

Myelodysplastic syndromes (MDS) are due to defective hematopoiesis in bone marrow characterized by cytopenia and dysplasia of blood cells, with a varying degree of risk of acute myeloid leukemia (AML). Currently, the only potentially curative strategy is hematopoietic stem cell transplantation (HSCT). Many patients are ineligible for HSCT, due to late diagnosis, presence of co-morbidities, old age and complications likely due to graft-versus-host disease (GvHD). As a consequence, patients with MDS are often treated conservatively with blood transfusions, chemotherapy, immunotherapy etc. based on the grade and manifestations of MDS. The development of chimeric antigen receptor (CAR)-T cell therapy has revolutionized immunotherapy for hematological malignancies, as evidenced by a large body of literature. However, resistance and toxicity associated with it are also a challenge. Hence, there is an urgent need to develop new strategies for immunological and hematopoetic management of MDS. Herein, we discuss current limitations of CAR T-cell therapy and summarize novel approaches to mitigate this. Further, we discuss the in vivo activation of tumor-specific T cells, immune check inhibitors (ICI) and other approaches to normalize the bone marrow milieu for the management of MDS.

Navigating first-line therapies for extensive-stage small-cell lung cancer: a frequentist network meta-analysis and systematic review.

Aim: To identify the optimal first-line treatment for patients with extensive-stage small-cell lung cancer (ES-SCLC). Materials & methods: We conducted a network meta-analysis (CRD42023486863) to systematically evaluate the efficacy and safety of eight first-line treatment regimens for ES-SCLC, including 15 clinical trials. Results: Our analysis showed that the PD-1/PD-L1 + etoposide combined with platinum (EP) and PD-L1 + vascular endothelial growth factor (VEGF) + EP regimens significantly enhanced overall survival and progression-free survival, with subgroup analysis revealing that serplulimab ranked as the most promising option for improving overall survival. Integrating anti-angiogenesis drugs into immunochemotherapy presents potential benefits, with an increased incidence of adverse events necessitating further investigation. Conclusion: Our findings offer valuable insights for future research and for developing more effective treatment strategies for ES-SCLC, underscoring the critical need for continued innovation in this therapeutic area.

[Box: see text].

Treatment patterns and outcomes of high-grade immune checkpoint inhibitor-related pneumonitis in an oncology hospitalist service.

PURPOSE: Immune checkpoint inhibitors (ICI) have become standard of care for some types of lung cancer. Along with expanding usage comes the emergence of immune-related adverse events (irAEs), including ICI-related pneumonitis (ICI-P). Treatment guidelines for managing irAEs have been developed; however, how clinicians manage irAEs in the real-world setting is less well known. We aimed to describe the outcomes and care patterns of grade ≥ 3 ICI-P in an onco-hospitalist service. PATIENTS AND METHODS: We included patients with lung cancer treated with ICI who were admitted to an oncology hospitalist service with a suspicion of ICI-P. We described the hospitalization characteristics, treatment patterns, discharge practices, and clinical outcomes of patients with confirmed ICI-P. The primary outcome was time to start treatment for ICI-P. RESULTS: Among 49 patients admitted with a suspicion of ICI-P, 31 patients were confirmed to have ICI-P and subsequently received ICI-P directed treatment. Pulmonology was consulted in 97% of patients. Median time to start treatment for ICI-P was 1 day (IQR 0-3.5 days). All 31 patients received corticosteroids. Inpatient mortality was 32%. Majority of patients discharged with steroids were prescribed prophylaxis for gastritis and opportunistic infections. Thirty-eight percent of patients were seen by pulmonology and 86% were seen by the oncology team post-discharge. CONCLUSION: Our study confirms prior findings of high mortality among patients with high-grade ICI-P. Early diagnosis and treatment are key to improving clinical outcomes. Understanding the care patterns and adherence to treatment guidelines of clinicians caring for this patient population may help identify ways to further standardize management practices and improve patient outcomes.

Treatment strategy for HER2-negative advanced gastric cancer: salvage-line strategy for advanced gastric cancer.

After immune checkpoint inhibitor (ICI) comes into third-line treatment of advanced gastric cancer, the therapeutic strategy has been dramatically changed. Recent first-line regimen, which consists of ICI and chemotherapeutic agents, prolonged progression-free survival, and subsequent treatment options enabled continuous treatment beyond second-line therapy. Moreover, the advent of vascular endothelial growth factor (VEGF)-targeted agents including angiogenesis inhibitors and TKIs provides an opportunity of considering the interaction between ICI and anti-VEGF agents, and facilitating novel treatment proposal. Although clinical benefit of prolonged VEGF blockade after disease progression has not been confirmed in gastric cancer, combination therapy of cytotoxic agents and anti-VEGF agent, such as irinotecan plus ramucirumab demonstrated favorable objective response rate and progression-free survival in third- or later-line setting. In this review, we discuss recent progress and future directions of later-line treatments of HER2-negative advancer gastric cancer.

MMP1, IL-1ß, sTNFR-1, and IL-6 are prognostic factors for patients with unresectable or metastatic renal cell carcinoma treated with immune checkpoint inhibitors.

BACKGROUND: Few studies have reported reliable prognostic factors for immune checkpoint inhibitors (ICIs) in renal cell carcinoma (RCC). Therefore, we investigated prognostic factors in patients treated with ICIs for unresectable or metastatic RCC. METHODS: We included 43 patients who received ICI treatment for RCC between January 2018 and October 2021. Blood samples were drawn before treatment, and 73 soluble factors in the plasma were analyzed using a bead-based multiplex assay. We examined factors associated with progression-free survival (PFS), overall survival (OS), and immune-related adverse events (irAE) using the Chi-squared test, Kaplan-Meier method, and the COX proportional hazards model. RESULTS: Patients exhibited a median PFS and OS of 212 and 783 days, respectively. Significant differences in both PFS and OS were observed for MMP1 (PFS, p < 0.001; OS, p = 0.003), IL-1ß (PFS, p = 0.021; OS, p = 0.008), sTNFR-1 (PFS, p = 0.017; OS, p = 0.005), and IL-6 (PFS, p = 0.004; OS, p < 0.001). Multivariate analysis revealed significant differences in PFS for MMP1 (hazard ratio [HR] 5.305, 95% confidence interval [CI], 1.648-17.082; p = 0.005) and OS for IL-6 (HR 23.876, 95% CI, 3.426-166.386; p = 0.001). Moreover, 26 patients experienced irAE, leading to ICI discontinuation or withdrawal. MMP1 was significantly associated with irAE (p = 0.039). CONCLUSION: MMP1 may be associated with severe irAE, and MMP1, IL-1ß, sTNFR-1, and IL-6 could serve as prognostic factors in unresectable or metastatic RCC treated with ICIs. MMP1 and IL-6 were independent predictors of PFS and OS, respectively. Thus, inhibiting these soluble factors may be promising for enhancing antitumor responses in patients with RCC treated with ICIs.

Molecular Imaging of PD-1 Unveils Unknown Characteristics of PD-1 Itself by Visualizing "PD-1 Microclusters".

Programmed cell death-1 (PD-1) is one of the most famous coinhibitory receptors that are expressed on effector T cells to regulate their function. The PD-1 ligands, PD-L1 and PD-L2, are expressed by various cells throughout the body at steady state and their expression was further regulated within different pathological conditions such as tumor-bearing and chronic inflammatory diseases. In recent years, immune checkpoint inhibitor (ICI) therapies with anti-PD-1 or anti-PD-L1 has become a standard treatment for various malignancies and has shown remarkable antitumor effects. Since the discovery of PD-1 in 1992, a huge number of studies have been conducted to elucidate the function of PD-1. Herein, this paper provides an overview of PD-1 biological findings and sheds some light on the current technology for molecular imaging of PD-1.

MiRNAs and Microbiota in Non-Small Cell Lung Cancer (NSCLC): Implications in Pathogenesis and Potential Role in Predicting Response to ICI Treatment.

Lung cancer (LC) is one of the most prevalent cancers in both men and women and today is still characterized by high mortality and lethality. Several biomarkers have been identified for evaluating the prognosis of non-small cell lung cancer (NSCLC) patients and selecting the most effective therapeutic strategy for these patients. The introduction of innovative targeted therapies and immunotherapy with immune checkpoint inhibitors (ICIs) for the treatment of NSCLC both in advanced stages and, more recently, also in early stages, has revolutionized and significantly improved the therapeutic scenario for these patients. Promising evidence has also been shown by analyzing both micro-RNAs (miRNAs) and the lung/gut microbiota. MiRNAs belong to the large family of non-coding RNAs and play a role in the modulation of several key mechanisms in cells such as proliferation, differentiation, inflammation, and apoptosis. On the other hand, the microbiota (a group of several microorganisms found in human orgasms such as the gut and lungs and mainly composed by bacteria) plays a key role in the modulation of inflammation and, in particular, in the immune response. Some data have shown that the microbiota and the related microbiome can modulate miRNAs expression and vice versa by regulating several intracellular signaling pathways that are known to play a role in the pathogenesis of lung cancer. This evidence suggests that this axis is key to predicting the prognosis and effectiveness of ICIs in NSCLC treatment and could represent a new target in the treatment of NSCLC. In this review, we highlight the most recent evidence and data regarding the role of both miRNAs and the lung/gut microbiome in the prediction of prognosis and response to ICI treatment, focusing on the link between miRNAs and the microbiome. A new potential interaction based on the underlying modulated intracellular signaling pathways is also shown.

Differential Immune Checkpoint Protein Expression in HNSCC: The Role of HGF/MET Signaling.

Although inhibitors targeting the PD1/PD-L1 immune checkpoint are showing comparably good outcomes, a significant percentage of head and neck squamous cell carcinoma (HNSCC) patients do not respond to treatment. Apart from using different treatment strategies, another possibility would be to target other immune checkpoints operating in these non-responding tumors. To obtain an overview of which checkpoint ligands are expressed on HNSCC tumor cells and if these ligands are affected by HGF/MET signaling, we used mRNA sequencing and antibody-based techniques for identifying checkpoint ligands in six HNSCC tumor cell lines. Furthermore, we compared our results to mRNA sequencing data. From the checkpoint ligands we investigated, VISTA was expressed the highest at the RNA level and was also the most ubiquitously expressed. PD-L2 and B7-H3 were expressed comparably lower and were not present in all cell lines to the same extent. B7-H4, however, was only detectable in the Detroit 562 cell line. Concerning the effect of HGF on the ligand levels, PD-L2 expression was enhanced with HGF stimulation, whereas other checkpoint ligand levels decreased with stimulation. B7-H4 levels in the Detroit 562 cell line drastically decreased with HGF stimulation. This is of interest because both the checkpoint ligand and the growth factor are reported to be connected to epithelial-mesenchymal transition in the literature.

Treatment response and recurrence of conjunctival melanoma with orbital invasion treated with immune checkpoint inhibitors: case report and literature review.

INTRODUCTION: Conjunctival melanoma (CM) has genetic characteristics that are similar to primary cutaneous melanoma (PCM). The management of advanced CM with orbital metastasis was limited until the adoption of novel immunotherapy agents that significantly improved the survival of metastatic PCM. PURPOSE: To review and compare the immune checkpoint inhibitor (ICI) treatment response in cases reported in the English literature with orbital involvement secondary to CM versus PCM. In addition, we report a case of local recurrence of CM in a young female after successful treatment with ICI. METHODS: In addition to reviewing the chart of one patient who presented to our clinic, we conducted a comprehensive literature review to identify CM cases and cases with orbital metastasis secondary to advanced CM and PCM. Outcomes included patient demographics, response to ICI, and associated adverse effects. RESULTS: There were ten cases with orbital involvement, four were secondary to CM, and six were metastasis from PCM. Orbital metastasis from PCM regressed following treatment with ICI agents, whereas those secondary to CM resolved completely. There were 19 cases of CM without orbital invasion. Of the 29 cases identified, complete resolution of ocular melanoma was achieved in 15 patients, representing 52% of the cases collectively, and none of them reported recurrence except in our case. CONCLUSION: CM with orbital invasion responds well to ICIs, with manageable toxic effects. Despite the complete resolution, close observation is needed as the recurrence risk remains.

Neoadjuvant immunotherapy in gastrointestinal cancers - The new standard of care?

The development of immune checkpoint inhibitors (ICI) offers novel treatment possibilities for solid cancers, with the crucial benefit of providing higher cure rates. These agents have become part of standard treatments in the metastatic and adjuvant setting for select cancers, such as melanoma, non-small cell lung cancer (NSCLC) or urological malignancies. Currently, there is ample clinical interest in employing ICI in a neoadjuvant setting with a curative intent. This approach is especially supported by the scientific rationale that ICI primarily stimulate the host immune system to eradicate tumor cells, rather than being inherently cytotoxic. Aside from tumor downstaging, neoadjuvant immunotherapy offers the potential of an in situ cancer vaccination, leading to a systemic adjuvant immunological effect after tumor resection. Moreover, preclinical data clearly demonstrate a synergistic effect of ICI with radiotherapy (RT), chemoradiotherapy (CRT) or chemotherapy (ChT). This review harmonizes preclinical concepts with real world data (RWD) in the field of neoadjuvant ICI in gastrointestinal (GI) cancers and discusses their limitations. We believe this is a crucial approach, since up to now, neoadjuvant strategies have been primarily developed by clinicians, whereas the advances in immunotherapy primarily originate from preclinical research. Currently there is limited published data on neoadjuvant ICI in GI cancers, even though neoadjuvant treatments including RT, CRT or ChT are frequently employed in locally advanced/oligometastatic GI cancers (i.e. rectal, pancreatic, esophagus, stomach, etc.). Utilizing established therapies in combination with ICI provides an abundance of opportunities for innovative treatment regimens to further improve survival rates.

Circulating tumor DNA-based molecular residual disease detection for treatment monitoring in advanced melanoma patients.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have substantially improved overall survival in patients with advanced melanoma; however, the lack of biomarkers to monitor treatment response and relapse remains an important clinical challenge. Thus, a reliable biomarker is needed that can risk-stratify patients for disease recurrence and predict response to treatment. METHODS: A retrospective analysis using a personalized, tumor-informed circulating tumor DNA (ctDNA) assay on prospectively collected plasma samples (n = 555) from 69 patients with advanced melanoma was performed. Patients were divided into three cohorts: cohort A (N = 30), stage III patients receiving adjuvant ICI/observation; cohort B (N = 29), unresectable stage III/IV patients receiving ICI therapy; and cohort C (N = 10), stage III/IV patients on surveillance after planned completion of ICI therapy for metastatic disease. RESULTS: In cohort A, compared to molecular residual disease (MRD)-negative patients, MRD-positivity was associated with significantly shorter distant metastasis-free survival (DMFS; hazard ratio [HR], 10.77; p = .01). Increasing ctDNA levels from the post-surgical or pre-treatment time point to after 6 weeks of ICI were predictive of shorter DMFS in cohort A (HR, 34.54; p < .0001) and shorter progression-free survival (PFS) in cohort B (HR, 22; p = .006). In cohort C, all ctDNA-negative patients remained progression-free for a median follow-up of 14.67 months, whereas ctDNA-positive patients experienced disease progression. CONCLUSION: Personalized and tumor-informed longitudinal ctDNA monitoring is a valuable prognostic and predictive tool that may be used throughout the clinical course of patients with advanced melanoma.

Prediction of response to immune checkpoint blockade in patients with metastatic colorectal cancer with microsatellite instability.

BACKGROUND: Mismatch repair-deficient (dMMR) tumors displaying microsatellite instability (MSI) represent a paradigm for the success of immune checkpoint inhibitor (ICI)-based immunotherapy, particularly in patients with metastatic colorectal cancer (mCRC). However, a proportion of patients with dMMR/MSI mCRC exhibit resistance to ICI. Identification of tools predicting MSI mCRC patient response to ICI is required for the design of future strategies further improving this therapy. PATIENTS AND METHODS: We combined high-throughput DNA and RNA sequencing of tumors from 116 patients with MSI mCRC treated with anti-programmed cell death protein 1 ± anti-cytotoxic T-lymphocyte-associated protein 4 of the NIPICOL phase II trial (C1, NCT03350126, discovery set) and the ImmunoMSI prospective cohort (C2, validation set). The DNA/RNA predictors whose status was significantly associated with ICI status of response in C1 were subsequently validated in C2. Primary endpoint was progression-free survival by immune RECIST (iRECIST) (iPFS). RESULTS: Analyses showed no impact of previously suggested DNA/RNA indicators of resistance to ICI, e.g. MSIsensor score, tumor mutational burden, or specific cellular and molecular tumoral contingents. By contrast, iPFS under ICI was shown in C1 and C2 to depend both on a multiplex MSI signature involving the mutations of 19 microsatellites hazard ratio cohort C2 (HRC2) = 3.63; 95% confidence interval (CI) 1.65-7.99; P = 1.4 × 10-3] and the expression of a set of 182 RNA markers with a non-epithelial transforming growth factor beta (TGFB)-related desmoplastic orientation (HRC2 = 1.75; 95% CI 1.03-2.98; P = 0.035). Both DNA and RNA signatures were independently predictive of iPFS. CONCLUSIONS: iPFS in patients with MSI mCRC can be predicted by simply analyzing the mutational status of DNA microsatellite-containing genes in epithelial tumor cells together with non-epithelial TGFB-related desmoplastic RNA markers.

Combined therapeutic effect of YHO-1701 with PD-1 blockade is dependent on natural killer cell activity in syngeneic mouse models.

The signal transducer and activator of transcription 3 (STAT3) signaling pathway is a key mediator of cancer cell proliferation, survival, and invasion. We discovered YHO-1701 as a small molecule inhibitor of STAT3 dimerization and demonstrated its potent anti-tumor activity using xenograft mouse models as monotherapy and combination therapy with molecular targeted drugs. STAT3 is also associated with cancer immune tolerance; therefore, we used the female CT26 syngeneic mouse model to examine the effect of combining YHO-1701 administration with PD-1/PD-L1 blockade. Pretreatment of the mice with YHO-1701 before starting anti-PD-1 antibody administration resulted in a significant therapeutic effect. In addition, the effect of monotherapy and combination treatment with YHO-1701 was significantly abolished by depleting natural killer (NK) cell activity. YHO-1701 was also found to restore the activity of mouse NK cells under inhibitory conditions in vitro. Furthermore, this combination therapy significantly inhibited tumor growth in an immunotherapy-resistant model of murine CMS5a fibrosarcoma. These results suggest that the combination of YHO-1701 with PD-1/PD-L1 blockade might be a new candidate for cancer immunotherapy involving the enhancement of NK cell activity in the tumor microenvironment.

Full spectrum flow cytometry-powered comprehensive analysis of PBMC as biomarkers for immunotherapy in NSCLC with EGFR-TKI resistance.

BACKGROUND: Clinical studies suggest that immune checkpoint inhibitor (ICI) monotherapy has limited benefits in non-small cell lung cancer (NSCLC) patients after epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) failure. However, data about efficacy of ICI plus chemotherapy remain controversial, probably attributed to the heterogeneity among such population, and robust efficacy biomarkers are urgent to explore. METHODS: A total of 60 eligible patients who received ICI plus chemotherapy after EGFR-TKI treatment failure were enrolled, 24 of whom peripheral blood mononuclear cell (PBMC) samples were collected at baseline and after 2 cycles of treatment. We have designed a 23-color-antibody panel to detect PBMC by full spectrum flow cytometry. RESULTS: For EGFR-TKI resistant NSCLC patients: 1) ICI plus chemotherapy achieved an objective response rate (ORR) of 21.7% and a median progression-free survival (PFS) of 6.4 months. 2) clinical characteristics associated with worse efficacy included liver metastasis and platelet-to-lymphocyte ratio (PLR) > 200. 3) the proportion of immune cell subset associated with better efficacy was higher baseline effective CD4+T cells (E4). 4) the baseline expression of immune checkpoint proteins (ICPs) on cell subsets associated with better efficacy included: higher expression of CD25 on dendritic cells (DC) and central memory CD8+T cells (CM8), and higher expression of Lymphocyte activation gene 3 (LAG-3) on effective memory CD8+T cells (EM8). 5) the expression of ICPs after 2 cycles of treatment associated with better efficacy included: higher expression of CD25 on CD8+T/EM8 /natural killer (NK) cells. 6) the dynamic changes of ICPs expression associated with worse efficacy included: significantly decrease of T cell immunoglobulin and ITIM domain (TIGIT) expression on regular T cells (Tregs) and decrease of V-domain immunoglobulin suppressor of T cell activation (VISTA) expression on Th1. 7) a prediction model for the efficacy of ICI plus chemotherapy was successfully constructed with a sensitivity of 62.5%, specificity of 100%, and area under curve (AUC) = 0.817. CONCLUSIONS: Some EGFR-TKI-resistant NSCLC patients could indeed benefit from ICI plus chemotherapy, but most patients are primary resistant to immunotherapy. Comprehensive analysis of peripheral immune cells using full spectrum flow cytometry showed that compared to the proportion of cell subsets, the expression type and level of ICPs on immune cells, especially CD25, were significantly correlated with the efficacy of immunotherapy.