Tumor PD-L1 Expression Research Articles

Effective treatment strategies and key factors influencing therapeutic efficacy in advanced SMARCA4-deficient non-small cell lung cancer

IntroductionSMARCA4/BRG1-deficient non-small cell lung cancer (SD-NSCLC) with high invasiveness and poor prognosis is associated with primary resistance to standard treatment, especially in late-stage patients. This study aimed to explore effective treatments and identify critical factors impacting therapeutic efficacy to enhance outcomes for SD-NSCLC patients. Methods103 SD-NSCLC patients in stage III/IV diagnosed by immunohistochemistry from May 2019 to March 2024 were included in this study. We assessed the patients’ clinical and genetic features, analyzed the clinical outcomes of local treatment and immunotherapy according to the TNM stage, and further evaluated the factors impacting therapeutic efficacy. ResultsIn stage III patients, no significant differences in the median progression-free survival (mPFS) and median overall survival (mOS) were observed between patients receiving local treatment at the primary site and those who did not (p > 0.05), while adding ICIs (immune checkpoint inhibitors) to local treatment significantly improved mPFS compared with non-ICIs (15.0 vs. 7.7 months, p = 0.033), though not mOS (p > 0.05). For stage IV patients, ICIs significantly improved mPFS (8.9 vs. 4.2 months, p = 0.006) and mOS (19.7 vs. 13.1 months, p = 0.007) compared to non-ICIs treatments. However, among ICIs-treated patients, the addition of local treatment to the primary lesion did not significantly affect mPFS and mOS (p > 0.05). Patients with STK11/KEAP1 mutations had significantly shorter mPFS (3.6 vs. 16.2 months, p = 0.001) and mOS (17.7 vs. 31.3 months, p = 0.002), while no significant difference was observed in mPFS and mOS in patients with different tumor mutation burden (TMB) and PD-L1 expression levels. ConclusionICIs to local treatment shows promising results for locally advanced patients with SD-NSCLC, and first-line ICIs are associated with improved survival in metastatic SD-NSCLC. STK11/KEAP1 mutations may be linked to reduced efficacy of immunotherapy.

IMMU-50. IMPACT OF SARS-COV-2 MRNA VACCINES ON PD-L1 EXPRESSION IN INTRACRANIAL TUMORS

Abstract Although immune checkpoint inhibitor (ICI) effectiveness is correlated with intra-tumoral PD-L1 expression, there are no clinically available methods to improve sensitivity to ICIs by modulating PD-L1 expression. mRNA vaccines stimulate robust interferon-dependent innate immune activation leading to four-fold increases in PD-L1 expression on peripheral and intratumoral myeloid cells and enhanced sensitivity to immune checkpoint blockade in preclinical models (Sayour, Grippin, et al., NanoLetters, 2018; Mendez-Gomez, et al., Cell, 2024). We hypothesized that mRNA vaccines targeting SARS-COV-2 would similarly enhance PD-L1 expression in intracranial tumors. To test this hypothesis, we utilized institutional databases to identify 5,524 patients at our institution with pathology reports including the term “PD-L1” from August 2020 to November 2023. Pathological data and dates of SARS-COV-2 vaccination were compiled for each patient. Across the entire cohort (n=5,524), receipt of a SARS-COV-2 mRNA vaccine within 100 days of biopsy was associated with a 55% increase in mean tumor proportion score (TPS) (14% vs 8.9%, p=0.029). In the subset of patients with intracranial tumors (n=187), receipt of a SARS-COV-2 mRNA vaccine within 100 days of biopsy was associated with a massive increase in TPS (57% vs 7.2%, p<0.001). To evaluate the impact of this change on clinical outcomes with immunotherapy, we utilized a second institutional database to assemble a cohort of patients with Stage IV melanoma with intracranial metastasis treated with immune checkpoint blockade during the period August 2020 through November 2023. Patients who received a SARS-COV-2 vaccine within 100 days of initiation of ICI (n=10) exhibited numerically improved overall survival compared to those without SARS-COV-2 mRNA vaccine (n=38) (HR 0.50, 95% CI 0.22-1.2, p=0.06). Median overall survival was 545 days among patients without COVID mRNA vaccination and was not met among those with COVID mRNA vaccination. This data supports further investigation of the immune modulating effect of SARS-COV-2 mRNA vaccines in patients with intracranial tumors treated with immune checkpoint blockade.

Durvalumab Following Chemoradiotherapy for Stage III Non-small Cell Lung Cancer: Differences in Survival Based on Age and Post-Progression Systemic Therapy.

Concurrent chemoradiotherapy (cCRT) followed by 1 year of the immune checkpoint inhibitor (ICI) durvalumab is standard of care for patients with unresectable stage III nonsmall cell lung cancer (NSCLC). The purpose of this study was to evaluate survival outcomes of (1) cCRT followed by durvalumab in patients older versus younger than 75 years of age and (2) post-progression treatment with ICI alone versus chemotherapy alone versus combined ICI and chemotherapy. Patients with unresectable stage III NSCLC treated between January 2018 and July 2023 with cCRT followed by durvalumab were identified retrospectively. Progression-free survival (PFS) and overall survival (OS) from ICI start were analyzed in three cohorts aged < 65, 65-74, and ≥ 75 years. Multivariable Cox proportional hazard regression modelling of factors associated with OS was undertaken. Logistic regression analysis identified risk factors of early durvalumab discontinuation for toxicity. Time from first salvage drug treatment to death (OS-2) was described. A total of 472 patients were analyzed: the proportions aged < 65, 65-74, and ≥ 75 years were 34.3%, 42.8%, and 22.9%, respectively. Odds of early durvalumab discontinuation was 2.2-fold greater in the oldest (versus youngest) cohort. Age associated differences in median PFS (26.7months, 20.3months, and 14.2months; p< 0.001) and OS (60.8months, 44.4 months, and 27.6 months; p< 0.001) were observed. On multivariable analysis, factors associated with shorter OS were age ≥ 75years (versus < 65), performance status 2/3 (versus 0/1), stage IIIC (versus IIIA), neutrophil to lymphocyte ratio (per 7.43 unit increase), Charlson comorbidity index (per 1 unit increase), tumoral PD-L1 expression < 1% (versus ≥ 50%, 1-49%, or unknown), and squamous histology (versus non-squamous). Of 264 patients with disease progression, 48.5% received subsequent drug therapy. Median OS-2 was longer with ICI alone (9.9 months) or ICI-chemotherapy (11.8 months) than platinum doublet chemotherapy (6.7 months.) For recurrences < 6 months from the last durvalumab infusion, OS-2 were similar across treatment groups. In the studied cohort, OS was significantly shorter for patients ≥ 75 years of age treated with cCRT followed by durvalumab compared to those < 65 years. Post-progression systemic therapy was associated with modest efficacy, underscoring the need for new therapies.

Photo-Thermally Controllable Tumor Metabolic Modulation to Assist T Cell Activation for Boosting Immunotherapy.

Glycolysis is crucial for tumor cell proliferation, supporting their energy needs and influencing the tumor microenvironment (TME). On one hand, increased lactate levels produced by glycolysis acidifies the TME, inhibiting T cell activity. On the other hand, glycolysis promotes the expression of PD-L1 through various mechanisms, facilitating immune evasion. Therefore, controlled modulation of glycolysis in tumor cells to subsequently improve the immune tumor microenvironment holds significant implications for clinical cancer treatment and immune regulation. To reverse the immunosuppressive microenvironment caused by tumor glycolysis and reduce tumor immune escape, we developed a photo-thermal-controlled precision drug delivery platform to regulate tumor metabolism and aid in the activation of T cells, thereby enhancing immunotherapy. First, hollow mesoporous Prussian blue (HPB) was prepared, and the glycolysis inhibitor 3-bromopyruvate (3-BrPA) was encapsulated within HPB using the phase-change material 1-tetradecanol, resulting in B/T-H. This product was then modified with tumor cell membranes to obtain a photo-thermal controllable regulator (B/T-H@Membrane, B/T-HM). Due to the excellent drug loading and photo-thermal properties of HPB, upon reaching the tumor, B/T-HM can rapidly heat under 808 nm irradiation, causing the 1-tetradecanol to transition to a liquid phase and release 3-BrPA, which effectively inhibits tumor glycolysis through the HK2 pathway, thereby reducing tumor cell proliferation, decreasing lactate production, and downregulating tumor PD-L1 expression. In synergy with photo-thermal and αPD-1, this photo-thermally controllable metabolic-immune therapy effectively activates T cells to eliminate tumor. In response to the changes in immune microenvironment caused by tumor metabolism, a photo-thermal precision-controlled drug delivery platform was successfully developed. This platform reshapes the tumor immunosuppressive microenvironment, providing a new approach for T cell-based tumor immunotherapy. It also opens new avenues for photo-thermal controllable metabolic-immune therapy.

Temporal dynamics of immune cell patterns in bladder cancer patients receiving Bacillus Calmette-Guérin therapy.

Bacillus Calmette-Guérin (BCG) is capable of enhancing the infiltration of immune cells into the tumour. However the temporal dynamics of immune cell patterns in patients receiving BCG instillation remains unclear. Ninety-six patients who underwent intravesical BCG therapy, comprising 46 responders and 50 non-responders, were retrospectively enroled to explore the evolving immune landscape. This study involved a detailed examination of sequential samples collected before, during, and after BCG treatment to assess BCG's influence on the immune microenvironment, employing techniques such as immunohistochemistry, fluorescent multiplex immunohistochemistry, and mass spectrometry techniques. Our study found that initial BCG instillation leads to enhanced immune cell infiltration, correlating with treatment efficacy, with responders exhibiting more pronounced increases. Non-responders experience a rise in immune cell infiltration and PD-L1 expression during the first instillation, which returns to baseline after treatment. In non-responders, BCG re-challenge fail to further increase immune cell infiltration into the tumour or improve patient outcomes. Strikingly, proteomics data revealed that GBP1 expression was induced by BCG treatment in non-responders. Our findings demonstrated the induction of tumour PD-L1 expression by BCG in non-responders, and therefore provide insights for the combination of BCG and anti-PD1/anti-PD-L1 therapy.

Nuclear imaging of PD-L1 expression promotes the synergistic antitumor efficacy of targeted radionuclide therapy and immune checkpoint blockade.

In order to maximize synergistic effect of targeted radionuclide therapy (TRT) and immune checkpoint blockade (ICB) as well as reduce the toxicity, we pioneered a strategy guided by PD-L1-targeted nuclear medicine imaging for the combination of TRT and ICB towards precision cancer therapy. As a novel targeted radiotherapeutic agent, 177Lu-AB-3PRGD2 targeting integrin αvβ3 was developed to achieve sustained antitumor effect by introducing an albumin binder (AB) into the structure of 3PRGD2. The 177Lu-AB-3PRGD2 TRT as well as different types of combination therapies of 177Lu-AB-3PRGD2 TRT and anti-PD-L1 ICB were performed in animal models. The changes of PD-L1 expression in tumors after TRT were evaluated in vitro and in vivo by PD-L1-specific SPECT/CT imaging of 99mTc-MY1523. 177Lu-AB-3PRGD2 showed improved tumor uptake and prolonged tumor retention, leading to significantly enhanced tumor growth suppression. Moreover, 177Lu-AB-3PRGD2 TRT remodeled the tumor immune microenvironment by upregulating PD-L1 expression and increasing tumor-infiltrating CD8+ T cells, facilitating immunotherapy. We found that the anti-PD-L1 treatment was more effective during the upregulation of tumor PD-L1 expression, and the time window could be determined by 99mTc-MY1523 SPECT/CT. We developed a novel and long-acting radiotherapeutic agent 177Lu-AB-3PRGD2, and pioneered a strategy guided by PD-L1-targeted nuclear medicine imaging for the combination of TRT and ICB towards precision cancer therapy, optimizing the therapeutic efficacy and reducing the cost and potential toxicity risks. This strategy could also be adapted for clinical practice, combining conventional radiotherapy or chemotherapy with ICB to enhance therapeutic efficacy.

Cytochalasin H enhances sensitivity to gefitinib in non-small-cell lung cancer cells through inhibiting EGFR activation and PD-L1 expression

In our previous study, we have isolated cytochalasin H (CyH) from endophytic fungus derived from mangrove plant and found that CyH inhibited the proliferation of non-small cell lung cancer (NSCLC) cells. Recently, epidermal growth factor receptor (EGFR) activation and programmed cell death 1 ligand (PD-L1) expression have been demonstrated to mediate NSCLC resistance to gefitinib, first-generation EGFR tyrosine kinase inhibitor (EGFR-TKI). Here, we further investigated the effect of CyH on EGFR activation, PD-L1 expression, and gefitinib sensitivity in NSCLC cell lines, A549 (wild-type EGFR), HCC827 (EGFR mutation), and NCI-H1975 (dual EGFR mutations and acquired gefitinib resistance) and animal model. Our results showed that CyH significantly inhibited EGFR activation and PD-L1 expression in NSCLC cells. Additionally, CyH dramatically promoted the inhibitory effect of gefitinib on the proliferation of A549 and HCC827 cells, and enhanced the sensitivity to gefitinib in NCI-H1975 cells. Moreover, CyH increased the inhibitory effect of gefitinib on EGFR activation and PD-L1 expression in HCC827 and NCI-H1975 cells. Animal experiments further demonstrated that CyH significantly promoted the inhibitory effect of gefitinib on the growth of NSCLC and the expression of Ki-67, p-EGFR, and PD-L1 in NCI-H1975 NSCLC xenograft tumors of nude mice. Furthermore, CyH inhibited the activation of JAK3/STAT signaling pathway. Taken together, our findings suggest that CyH promotes the sensitivity to gefitinib in NSCLC cells through the inhibition of EGFR activation and PD-L1 expression.

Integrating single cell and bulk RNA sequencing data identifies RBM17 as a novel response biomarker for immunotherapy in bladder cancer.

Checkpoint inhibitors (CPIs) have been widely applied in the treatment of patients with bladder cancer (BLCA). However, there is still unmet need to dissect response predict biomarkers. To uncover CPI response-related marker genes in cancer cells, we utilized SCISSOR, integrating single-cell RNA and bulk RNA sequencing data. Transcriptomic and clinical data from IMvigor210, UNC-108, and BCAN/HCRN datasets were collected to evaluate and validate the identified biomarkers and signatures. Additionally, we analyzed TCGA-BLCA and local-BLCA RNA-seq data to investigate alternative splicing events (ASEs). Cell viability was assessed in T24 and UMUC3 cells with RBM17 upregulation or downregulation. Through SCISSOR analysis, we discovered that the expression levels of RBM17, TAP1, and PSMB8 were significantly associated with CPI response. Since PSMB8 displayed a highly positive correlation with TAP1, we developed a CPI response score (CRS) signature based on the expression profiles of RBM17 and TAP1. The CRS demonstrated robust predictive capacity in IMvigor210, UNC-108, and BCAN/HCRN datasets and was associated with higher tumor mutational burden (TMB), PD-L1 expression, and unique genomic features. Notably, RBM17 was not linked to the clinical outcomes of BLCA patients but positively correlated with BLCA cell proliferation in vitro. In the meantime, RBM17 was correlated with higher activity in core biological pathways, including antigen processing machinery, CD8 + T effector cells, cell cycle, DNA damage repair, epithelial-mesenchymal transition, histone regulation, and immune checkpoints. Moreover, the high-RBM17 group showed enrichment of LumU/Ba/sq subtypes but fewer FGFR3 alterations. Lastly, RBM17 significantly upregulated ASEs in BLCA samples, leading to higher neoantigen levels, a more inflamed tumor microenvironment, and improved CPI response. RBM17 is associated with higher ASEs and neoantigen levels, thereby potentiating the efficacy of CPI in BLCA. The established predictive signature, utilizing only two genes, has the potential to streamline clinical applications, providing a cost-effective alternative to expensive genomic, transcriptomic, and biological feature tests.

A PD-L1-Targeted Probe Cy5.5-A11 for In Vivo Imaging of Multiple Tumors.

PD-L1 is an immune checkpoint molecule mediating cancer immune escape, and its expression level in the tumor has been used as a biomarker to predict response to immune checkpoint inhibitor (ICI) therapy. Our previous study reveals that an 11 amino acid-long ANXA1-derived peptide (named A11) binds and degrades the PD-L1 protein in multiple cancers and is a potential peptide for cancer diagnosis and treatment. Near-infrared fluorescence (NIF) optical imaging of tumors offers a noninvasive method for detecting cancer and monitoring therapeutic responses. In this study, an NIF dye Cy5.5 was conjugated with A11 peptide to develop a novel PD-L1-targeted probe for molecular imaging of tumors and monitor the dynamic changes in PD-L1 expression in tumors. In vitro imaging studies showed that intense fluorescence was observed in triple-negative breast cancer MDA-MB-231, nonsmall cell lung cancer H460, and melanoma A375 cells incubated with Cy5.5-A11, and the cellular uptake of Cy5.5-A11 was efficiently inhibited by coincubation with unlabeled A11 or knockdown of cellular PD-L1 by shRNA. In vivo imaging studies showed accumulation of Cy5.5-A11 in the MDA-MB-231, H460, and A375 xenografts with good contrast from 0.5 to 24 h after intravenous injection, indicating that Cy5.5-A11 possesses the strong ability for in vivo tumor imaging. Moreover, the fluorescent signal of A11-Cy5.5 in the xenografts was successfully blocked by coinjection of unlabeled A11 peptide or knockdown of cellular PD-L1 by shRNA, indicating the specificity of Cy5.5-A11 targeting PD-L1 in tumor imaging. Our data demonstrate that Cy5.5-A11 is a novel tool for tumor imaging of PD-L1, which has the potential for detecting cancer and predicting ICI therapeutic responses.

Dysgerminomas: germ cell tumors exhibit high expression of PD-L1 and associated with high TILs and good prognosis

Ovarian germ cell tumors (OVGCTs) account for 28% of all diagnosed ovarian cancers, and malignant germ cell tumors specifically account for approximately 13% of diagnosed ovarian cancers in Saudi Arabia. Although most germ cell tumor patients have a high survival rate, patients who experience tumor recurrence have a poor prognosis and present with more aggressive and chemoresistant tumors. The use of immunotherapeutic agents such as PD-L1/PD-1 inhibitors for OVGCTs remains very limited because few studies have described the immunological characteristics of these tumors. This study is the first to investigate PD-L1 expression in ovarian germ cell tumors and explore the role of PD-L1 expression in tumor microenvironment cells and genetic alterations. A total of 34 ovarian germ cell tumors were collected from pathology archives. The collected tumor tissues included ten dysgerminomas, five yolk sac tumors, five immature teratomas, and one mature teratoma, and the remaining samples were mixed germ cell tumors. The tumors were analyzed using immunohistochemical analysis to determine PD-L1 expression, immune cell infiltration and cancer stem cell populations and their correlation with clinical outcome. Furthermore, the genetic alterations in different subtypes of germ cell tumors were correlated with PD-L1 expression and clinical outcome. Datasets for testicular germ cells (TGCTs) were retrieved from The Cancer Genome Atlas (TCGA) and analyzed using cBioPortal (cbioportal.org) and Gene Expression Profiling Interactive Analysis (GEPIA). Compared with yolk sac tumors, dysgerminomas highly express PD-L1 and are associated with high levels of tumor infiltrating lymphocytes (TILs) and stem cell markers. In addition, compared with PD-L1-negative yolk sac tissue, dysgerminomas/seminomas with high PD-L1 expression are associated with more genetic alterations and a better prognosis. Our findings will contribute to the knowledge about the potential benefits of ovarian cancer immunotherapy in specific subsets of germ cell tumor patients and the risk factors for resistance mediated by tumor microenvironment cells.

Comparative efficacy of chemo-immunotherapy combination regimens in the frontline setting for NSCLC based on reconstructed patient data

Immune checkpoint inhibitors (ICIs) have revolutionised the treatment of metastatic NSCLC and have become standard first-line therapy both as monotherapy, for patients with PD-L1 expression ≥50%, and in combination with chemotherapy (CT), regardless of PD-L1 expression. This study used an artificial intelligence technique, the IPDfromKM method, to reconstruct individual patient data from Kaplan-Meier curves of phase III randomised clinical trial results to provide a comparative overview of different first-line chemo-immunotherapy options. Overall survival (OS) was estimated using hazard ratios and restricted mean survival time (RMST). Ten clinical trials were included in the analysis. In the squamous population, combinations of cemiplimab + CT (HR = 0.56), pembrolizumab + CT (HR = 0.67), and nivolumab + ipilimumab + CT (HR = 0.71) significantly improved OS compared with CT alone, with no difference between treatments. At longer follow-up, nivolumab + ipilimumab + CT showed longer RMST compared to pembrolizumab + CT in the PD-L1 < 1% subgroup (24.9 months vs. 22.8 months). In non-squamous NSCLC, the survival benefit of ICIs + CT was much more homogeneous, with similar results across the different options. Overall, pembrolizumab + CT showed the best results both in terms of HR (0.68, 95%CI 0.60-0.77) and RMST at long follow-up (30.4 months in the PDL-1 ≥ 1% subgroup and 24 months in the PDL-1 < 1% population). In conclusion, there are some differences between frontline options for treating metastatic NSCLC based on tumour histology and PD-L1 expression. However, further head-to-head trials and longer follow-up are needed to clarify the clinical impact of these differences.

Adjuvant Nivolumab in High-Risk Muscle-Invasive Urothelial Carcinoma: Expanded Efficacy From CheckMate 274.

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.CheckMate 274 is a phase III, randomized, double-blind trial of adjuvant nivolumab versus placebo for muscle-invasive urothelial carcinoma (MIUC) at high risk of recurrence after radical resection. The primary end points of disease-free survival (DFS) in intent-to-treat (ITT) and tumor PD-L1 expression ≥1% populations were met. We report results at an extended median follow-up of 36.1 months in the ITT population. In addition, we report interim overall survival (OS) data for the first time and an exploratory analysis among patients with bladder primary tumors (muscle-invasive bladder cancer [MIBC]). Consistent DFS benefit with nivolumab versus placebo was observed in both the ITT (hazard ratio [HR], 0.71 [95% CI, 0.58 to 0.86]) and PD-L1 ≥1% (HR, 0.52 [95% CI, 0.37 to 0.72]) patients. The HR for OS with nivolumab versus placebo was 0.76 (95% CI, 0.61 to 0.96) in the ITT population and 0.56 (95% CI, 0.36 to 0.86) in the PD-L1 ≥1 population. Continuous benefit in nonurothelial tract recurrence-free survival and distant metastasis-free survival was also observed in both patient populations. The exploratory analysis of patients with MIBC also showed continued efficacy benefits, irrespective of PD-L1 status. No new safety signals were reported. Overall, these results further support adjuvant nivolumab as a standard of care for high-risk MIUC after radical resection.

6850 A Case of Anaplastic Thyroid Carcinoma With a Complete Metabolic Response to Pembrolizumab

Abstract Disclosure: E. Tirthani: None. J.T. Kung: None. Background: Anaplastic thyroid carcinoma (ATC) is an aggressive disease with limited therapeutic options and generally poor prognosis. Post-surgery, most patients are treated with a combination of chemotherapy, radiation, and tyrosine kinase inhibitors +/- immune checkpoint inhibitors. We describe a unique case of ATC with a complete metabolic response to pembrolizumab, a selective PD-1 inhibitor, as evidenced by imaging. Clinical Case: A 69-year-old female presented to the clinic for evaluation of a rapidly enlarging neck mass. The initial ultrasound showed a large mixed cystic-solid right thyroid nodule with irregular margins with micro- and macrocalcifications, which was biopsied. Cytology showed discohesive high-grade malignant tumor cells with enlarged nuclei, nuclear hyperchromasia in the background of necrosis, and dense neutrophilic infiltration concerning for ATC. A CT scan of the neck and chest showed a complex cystic thyroid mass with central necrosis and calcification with paratracheal, supraclavicular, and mediastinal lymphadenopathy. MRI of the brain was negative for metastatic disease. The patient underwent a total thyroidectomy with right and left level 6 and 7 neck dissection. Intra-operatively, gross extrathyroidal extension of the tumor was noted to the right carotid, larynx, right recurrent laryngeal nerve, and esophagus, with residual tumor left behind near the larynx. Pathology confirmed stage IVC ATC, positive for PIK3CA, NF1, p53 mutations, and BRAF negative. 90% of tumor cells showed PD-L1 expression on immunohistochemical staining. The post-surgical PET scan showed two discrete, well-defined foci of very intense FDG uptake, corresponding to the right lower cervical and para-esophageal lymph nodes with no evidence of distant metastasis. Systemic chemotherapy with carboplatin and paclitaxel (5 cycles) was initiated with concurrent intensity modulated radiation therapy (total 60 Gy/40 fractions to thyroid bed and bilateral neck). Repeat imaging showed minimal change in the size of the PET-positive lymph nodes. Immunotherapy was initiated and with just 2 cycles of 400 mg IV pembrolizumab, a repeat PET scan was obtained, which showed a complete metabolic response to therapy. Minimal residual FDG activity in the right supraclavicular region was thought to be secondary to posttreatment changes. The patient was able to resume her activities of daily living and had an improvement in appetite. The plan is to continue 400 mg IV pembrolizumab every 6 weeks while cautiously assessing for adverse effects from immunotherapy. Conclusion: It is rare to see a complete metabolic response to therapy with pembrolizumab without concurrent use of tyrosine kinase inhibitors in patients with ATC. A high tumoral PD-L1 expression may be the key to having this kind of dramatic response. Presentation: 6/3/2024

Enhancing the Efficacy of Breast Cancer Immunotherapy Using a Smac-Armed Oncolytic Virus.

It has been shown that the response rate of TNBC is dependent on the level of PD-L1 and the tumor microenvironment (TME). Approaches that alter the TME can improve the efficacy of ICIs. Background: We have engineered a Smac-armed oncolytic virus by inserting a Smac transgene into the genome of a vesicular stomatitis virus to generate VSV-S. Our previous study shows that the anticancer efficacy of VSV-S is more potent than that of wild-typed VSV in a subcutaneous TNBC mouse model. VSV-S treatment reverts the immunosuppressive TME by reducing MDSCs and TAMs, while increasing infiltration of neutrophils and CD8+ T cells. Methods: VSV-S was used to treat TNBC in an orthotopic mouse model, and in a combination therapy with an anti-PD-1 antibody to treat metastatic TNBC in a mouse model. Changes in the TME were evaluated. Results: In this current study, we show that neoadjuvant VSV-S treatment of primary orthotopic TNBC tumors in mice drastically lowered lung metastasis after surgical removal of the primary tumor, and significantly increased the survival rate. The mechanism of action and changes to the TME were delineated, among which one significant marker is the elevation of PD-L1 expression in tumors. In the TNBC lung metastasis mouse model, pulmonary treatment with VSV-S greatly enhanced the efficacy of ICI treatment. Conclusions: Our results suggest that the combination of oncolytic virus and ICI therapies has the potential to substantially improve the outcome of TNBC treatment.

HLA-E and NKG2A Mediate Resistance to M. bovis BCG Immunotherapy in Non-Muscle-Invasive Bladder Cancer.

Mycobacterium bovis Bacillus Calmette-Guerin (BCG) is the primary treatment for non-muscle-invasive bladder cancer (NMIBC), known to stimulate inflammatory cytokines, notably interferon (IFN)-γ. We observed that prolonged IFN-γ exposure fosters adaptive resistance in recurrent tumors, aiding immune evasion and tumor proliferation. We identify HLA-E and NKG2A, part of a novel NK and T cell checkpoint pathway, as key mediators of resistance in BCG-unresponsive NMIBC. IFN-γ enhances HLA-E and PD-L1 expression in recurrent tumors, with an enrichment of intra-tumoral NKG2A-expressing NK and CD8 T cells. CXCL9+ macrophages and dendritic cells and CXCL12-expressing stromal cells likely recruit CXCR3/CXCR4-expressing NK and T cells and CXCR7+ HLA-EHIGH tumor cells. NK and CD8 T cells remain functional within BCG-unresponsive tumors but are inhibited by HLA-E and PD-L1, providing a framework for combined NKG2A and PD-L1 blockade strategy for bladder-sparing treatment of BCG-unresponsive NMIBC.

525. PALLIATIVE MULTIMODALITY-THERAPY, EVEN WITH ABBREVIATED IMMUNOTHERAPY CAN MAKE CURATIVE SURGERY FOR SYNCHRONOUS LUNG AND ESOPHAGEAL CANCER POSSIBLE: A CASE REPORT

Abstract Background Synchronous lung and esophageal carcinomas are problematic. When both cancers are locally advanced, combined surgical treatment is rarely possible because of high-risk or insufficient respiratory reserve. Palliative treatment including immunotherapy can sometimes offer significant tumor response and potentially prolong survival in patients with PDL-1 tumor expression. However the place of immunotherapy for potentially rendering inoperable patients operable is still unknown. Methods Case report: A 78-year-old male with smoking history was diagnosed with synchronous locally advanced adenocarcinoma of the Gastroesophageal Junction (GEJ) cT3cN1cM0 and bilateral lung adenocarcinomas stage 4a, cT2cN1cM1a (right lower lobe 43mm confirmed by CT-guided biopsy, left upper lobe 32mm and additional S6 left lower lobe nodule). The patient was considered incurable by MDT and palliative treatment was offered as both cancers had significant PDL-1 expression (GEJ: CPS score &amp;gt;1, Lung: PDL-1 expression 90%). Pembrolizumab immunotherapy was started but poorly tolerated (severe myositis) and stopped again after only 6 weeks. The left-sided lung cancer had by then already regressed and stereotactic irradiation (SBRT 5x12Gy) of the right-side lung cancer was administered resulting in further local tumor control (figure). Endoscopic tumor re-evalution showed a Siewert type 2 tumor (uT3N1) similar to the initial endoscopy 15 months before. Both side lung adenocarcinomas remained regressed and the left lower lobe nodule was unchanged (6mm). Mediastinal lymph node staging by EBUS was negative. Thirteen months after initial diagnosis, 4 cycles of neo-adjuvant chemotherapy (FLOT) were administered. Combined synchronous surgery was finally done 16 months after initial diagnosis. A minimally invasive combined resection included a laparoscopic &amp; thoracoscopic Ivor-Lewis MIE, left thoracoscopic wedge of the lower lobe nodule and a right lower lobectomy with radical lymph node dissection. Post-operative course was smooth: Clavien-Dindo score 1, hospital stay 18 days. Final pathology Distal third adenocarcinoma (1.5x1.2cm above Z-line) with major partial response ypT2N0M0, R0, 0/43 lymph nodes (subcarinal signs of nodal response), right lower lobe tumor of 60x55mm with residual 1.2mm focus of residual viable adenocarcinoma (ypTisN0M0, R0) and left lower lobe hamartoma (6mm). Follow-up showed no recurrence 9 months after surgery (25 months from initial diagnosis). Conclusions: 1) Despite much abbreviated palliative immunotherapy (6 weeks), SBRT and FLOT our patient was down-staged within 16 months from an initially palliative situation to a potential cure with complete resection of all tumors. 2) Synchronous combined radical laparoscopic &amp; thoracoscopic Ivor-Lewis esophagectomy with lung lobectomy can be feasible after immuno-, chemo- and radiotherapy even in elderly patients.

Synthesis and evaluation of anti-PD-L1-B11 antibody fragments for PET imaging of PD-L1 in breast cancer and melanoma tumor models

There is a critical need to non-invasively assess the PD-L1 expression in tumors as a predictive biomarker for determining the efficacy of anti-PD-1/PD-L1 immunotherapies. Non-invasive imaging modality like positron emission tomography (PET) can be a powerful tool to assess the PD-L1 expression in the whole body including multiple metastases as a patient selection criterion for the anti-PD-1/PD-L1 immunotherapy. In this study, we synthesized B11-nanobody, B11-scFv and B11-diabody fragments from the full-length anti-PD-L1 B11 IgG. Out of the three antibody fragments, B11-diabody showed higher nM affinity towards PD-L1 antigen as compared to B11-scFv and B11-nanobody. All three antibody fragments were successfully radiolabeled with 64Cu, a PET radioisotope. For radiolabeling, the antibody fragments were first conjugated with p-SCN-Bn-NOTA followed by chelation with 64Cu. All three radiolabeled antibody fragments were found to be stable in mouse and human sera for up to 24 h. Additionally, all three [64Cu]Cu-NOTA-B11-antibody fragments were evaluated in PD-L1 negative and human PD-L1 expressing cancer cells and subcutaneous tumor models. Based on the results, [64Cu]Cu-NOTA-B11-diabody has potential to be used as a PET imaging probe for assessing PD-L1 expression in tumors as early as 4 h post-injection, allowing faster assessment compared to the full length IgG based PET imaging probe.

Immunotherapy and PD-L1 Tumor Expression in Moroccan Non-Small Cell Lung Cancer Patients with Various Metastasis.

The question of whether tumor expression of PD-L1 and the presence of distant metastasis could influence the efficacy of immunotherapy represents a major challenge and needs to be further elucidated. The aim of this study is to evaluate the predictive significance of tumor expression of PD-L1 as well as the number and site of metastasis in non-small cell lung cancer (NSCLC) among Moroccan patients treated with immunotherapy. Between January 2019 and February 2023, we recruited Moroccan patients with metastatic NSCLC. All were treated with immunotherapy, either as monotherapy or in combination with chemotherapy. Immunohistochemistry was used to assess PD-L1 (clone 22C3) and ALK (clone D5F3) status. EGFR status was established by qPCR. Tumor PD-L1 expression was classified into 2 levels: TPS <1% (negative expression) and TPS ≥1% (positive expression). Statistical analysis was performed using SPSS Statistics V.21 software. The median age of patients (N=40) was 67 years (39- 92 years) and the sex ratio was 9. Disease dissemination revealed that 22.5% (N=9) of patients had a metastatic burden ≥ 3 (MB≥3). As for the sites of metastasis, the results showed that 20% (N=8), 10% (N=4), 42.5% (N=17), 22.5% (N=9), 27.5% (N=11), 45% (N=18) and 27.5% (N=11) of patients had developed lymph node, liver, bone, brain, pleural, contralateral lung and adrenal metastasis respectively. Positive PD-L1 expression was significantly associated with shorter overall survival (OS = 17.19 vs. 28.85 months, p=0.01). High metastatic burden (MB ≥ 3) was associated with lower objective response rate (ORR), shorter progression-free survival (PFS), and reduced OS, respectively (ORR = 0 vs. 58.06%, p=0.002; PFS = 10.23 vs. 25.27 months, p=0.001; and OS = 11.60 vs. 27.91 months, p=0.003). Only the presence of osseous metastasis was significantly associated with lower ORR, shorter PFS, and OS compared to other metastatic locations (ORR = 5.88 vs. 73.9%, p=0.000; PFS = 10.72 vs. 31.33 months, p=0.000; and OS = 11.39 vs. 36.17 months, p=0.000). Finally, the presence of hepatic metastasis was significantly associated with shorter PFS (10.75 months) compared to those without hepatic metastasis (22.53 months) (p=0.046). Finally, the results of the multivariate analysis revealed that the presence of bone metastasis was strongly correlated with a significant decrease in progression-free survival (p=0.001) as well as overall survival (p=0.002). Our results suggest that tumor expression of PD-L1 and metastatic burden should play a significant role in predicting the response to immunotherapy. Furthermore, it is important to note that the presence of osseous and hepatic metastasis could negatively influence the clinical outcomes of immunotherapy.

Concerning Safety and Efficacy of Concurrent and Consolidative Durvalumab With Thoracic Radiation Therapy in PDL1-Unselected Stage III Non-Small Cell Lung Cancer: Brief Report

IntroductionConsolidative durvalumab, an anti-programmed death ligand 1 (PDL1) immune checkpoint inhibitor, administered after concurrent chemoradiation improves outcomes of patients with locally advanced non-small cell lung cancer (NSCLC) without substantially increasing toxicities. We studied a chemotherapy-free regimen of thoracic radiotherapy (RT) with concurrent and consolidative durvalumab. MethodsThis single-arm phase II trial enrolled patients with stage III NSCLC (regardless of tumor PDL1 expression), performance status ECOG 0-1, adequate pulmonary function, and RT fields meeting standard organ constraints. Participants received two cycles of durvalumab (1500 mg every 4 weeks) concurrently with thoracic RT (60 Gy in 30 fractions), followed by up to 13 cycles of consolidative durvalumab. ResultsAfter 10 patients were enrolled, the trial was closed due to poor clinical outcomes. With a median follow-up of 12 months, five patients had disease progression and eight patients died. Six patients experienced 15 treatment-related, grade ≥3 events, including one grade 4 acute kidney injury during consolidation and two fatal pulmonary events. One fatal pulmonary event occurred during the concurrent phase in an active smoker; the other occurred after the first cycle of consolidative durvalumab. The primary endpoint of progression-free survival (PFS) at 12 months was 20% (50% for PDL1≥1% versus 0% for PDL1 unavailable or <1%). Median overall survival (OS) was not reached, 10.5 months, and 7 months, for PDL1 ≥1%, <1%, and unavailable, respectively. ConclusionsIn PDL1 unselected stage III NSCLC, thoracic RT plus concurrent and consolidative durvalumab is associated with high-grade toxicity and early disease progression.

The influence of PD-L1 expression levels on the efficacy of combination therapy in thymic epithelial tumors.

The significant expression of PD-L1 in thymic epithelial tumors (TETs) has been confirmed, and immunotherapy and its combination therapy have been effective in TETs. However, there is no present evidence that the expression levels of PD-L1 affects the efficacy of combination therapy. Our study aimed to shed light on this relationship. Patients with thymic epithelial tumors (TETs) from multicenter hospitals were retrospectively identified. Objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and immune-related adverse events (irAEs) in 22 patients were included. We divided the patients the 22 patients with PD-L1 test into three levels (high expression, low expression and no expression) and analyzed the relationship between the levels of PD-L1 expression and the efficacy of combination therapy. Combination therapy showed an effective benefit in 22 patients with TETs, the median PFS (mPFS) was 16 months (95% CI: 8.5-23.5) and the median OS (mOS) was 38 months (95% CI: 21.5-54.5). Cox-regressive analysis found whether PD-L1 expression affected the PFS of patients (p = 0.017). Among the patients with PD-L1 expression, the levels of expression were correlated with curative effect (Kruskal-Wallis test, PFS: P = 0.012; OS: P = 0.01), and high expression group was along with better efficacy than low expression (Wilcoxon test, P = 0.01). Moreover, in 17 patients treated with immunotherapy combined with chemotherapy, the expression of PD-L1 was also associated with efficacy (Kruskal-Wallis test, p = 0.021). PD-L1 expression affects the PFS of patients. High expression of PD-L1 patients with TETs responded better to combination therapy, which could provide a therapeutic option in clinic. Besides, other targeted treatments should be considered.