Tumor PD-L1 Research Articles

Triple Negative Breast Cancer: Molecular Subtype-Specific Immune Landscapes with Therapeutic Implications.

Triple Negative Breast Cancer (TNBC) is characterized by distinct molecular subtypes with unique biological and clinical features. This systematic review aimed to identify articles examining the differences in the tumor immune microenvironment (TIME) across different TNBC molecular subtypes. Six studies meeting inclusion criteria were analyzed, utilizing gene expression profiling and bioinformatic analyses to classify TNBC samples into molecular subtypes, as well as immunohistochemistry and cell deconvolution methods to characterize the TIME. Results revealed significant heterogeneity in immune cell composition among TNBC subtypes, with the immunomodulatory (IM) subtype demonstrating robust immune infiltration, composed mainly of adaptive immune cells along with an increased density of CTLA-4+ and PD-1+ TILs, high PD-L1 tumor cell expression, and upregulation of FOXP3+ Tregs. A more immunosuppressive TIME with a predominance of innate immune cells and lower levels of tumor-infiltrating lymphocytes (TILs) was observed in luminal androgen receptor (LAR) tumors. In mesenchymal stem-like (MSL) tumors, the TIME was mainly composed of innate immune cells, with a high number of M2 tumor-associated macrophages (TAMs), while the BL and M tumors displayed poor adaptive and innate immune responses, indicating an "immune-cold" phenotype. Differential activation of signaling pathways, genomic diversity, and metabolic reprogramming were identified as contributors to TIME heterogeneity. Understanding this interplay is crucial for tailoring therapeutic strategies, especially regarding immunotherapy.

Tumor inflammatory microenvironment contribution to survival in resected upstaged adenocarcinomas

IntroductionTumor Inflammatory microenvironment (TIME) encompasses several immune pathways modulating cancer development and escape that are not entirely uncoded. The results achieved with immunotherapy elicited the scientific debate on TIME also in non-small cell lung cancer (NSCLC). We aimed to investigate whether TIME (in terms of PD-L1 expression and/or Tumor Infiltrating Lymphocytes - TILs) played a separate role in terms of survival (OS) in resected upstaged lung adenocarcinomas (ADCs), excluding other perioperative variables as confounders. Materials and methodsThis retrospective study included 50 patients with a clinically resectable lung ADC, undergoing surgery (lobectomy or segmentectomy) at the Thoracic Unit of Padova University Hospital between 2016 and 2022 and receiving an unexpected pathological upstaging (IIB or higher). ResultsDespite microscopical variables increasing from IIB to IIIB, survival was not significantly related to them. OS was better in TIME-active patients (defined as the presence of positive PD-L1 and/or TILs>10 %) than double negatives (PD-L1-/TILs-) (p = 0.01). In IIB or higher ADCs, TIME-active patients showed an improved survival compared to double negatives, merging the current TIME theories. ConclusionTIME seems to be associated with survival independently from other microscopical parameter, even in case of resected upstaged adenocarcinomas.

Immune features are associated with response to neoadjuvant chemo-immunotherapy for muscle-invasive bladder cancer

Neoadjuvant cisplatin-based chemotherapy is standard of care for muscle-invasive bladder cancer (MIBC). Immune checkpoint inhibition (ICI) alone, and ICI in combination with chemotherapy, have demonstrated promising pathologic response (<pT2) in the neoadjuvant setting. In LCCC1520 (NCT02690558), a phase 2 single-arm trial of neoadjuvant chemo-immunotherapy (gemcitabine and cisplatin plus pembrolizumab; NAC-ICI) for MIBC, 22/39 patients responded (pathologic downstaging as primary outcome), as previously described. Here, we report post-hoc correlative analyses. Treatment was associated with changes in tumor mutational profile, immune gene signatures, and RNA subtype switching. Clinical response was associated with an increase in plasma IL-9 from pre-treatment to initiation of cycle 2 of therapy. Tumors harbored diverse predicted antigen landscapes that change across treatment and are associated with APOBEC, tobacco, and other etiologies. Higher pre-treatment tumor PD-L1 and TIGIT RNA expression were associated with complete response. IL-8 signature and Stroma-rich subtype were associated with improved response to NAC-ICI versus neoadjuvant ICI (ABACUS trial, NCT02662309). Plasma IL-9 represents a potential predictive biomarker of NAC-ICI response, while tumor IL-8 signature and stroma-rich subtype represent potential predictive biomarkers of response benefit of NAC-ICI over neoadjuvant ICI. Future efforts must include additional independent biomarker discovery and validation, ultimately to improve the selection of patients for ICI-related treatments.

Abstract B008: High expression of the exhaustion markers PD1 and PD-L1 in non-muscle invasive bladder cancer is associated with poor outcome following Bacillus Calmette-Guérin immunotherapy

Abstract Introduction: The recommended treatment for high-risk non-muscle invasive bladder cancer (NMIBC) is intravesical instillations of Bacillus Calmette-Guérin (BCG). However, 40 % experience recurrence within 5 years despite completing BCG treatment. T cell exhaustion has been associated with poor outcome following treatment with BCG. Here we investigated if T cell exhaustion, characterized by protein expression of PD1 and PD-L1 measured in paired samples obtained before and after BCG treatment could further explain BCG response and help predict outcome in patients with NMIBC. Methods: We included 111 patients with NMIBC, from which we had 183 TURB-T samples obtained before and after BCG treatment. Using immunohistochemistry (IHC) staining of sections from tissue microarrays (TMAs) with triplicate core biopsies, we investigated the protein expression of the exhaustion markers PD1 (clone EP239) and PD-L1 (clone 22c3). Data was analyzed using digital pathology software (Visiopharm®), where tissue areas were defined as either carcinoma or stroma based on PanCK staining. Cells were scored as positive when detection of a nucleus was combined with a positive PD1 or PD-L1 stain, which was based on visually defined thresholds to differentiate between positive and unspecific staining. In total, 167 samples from 105 patients were considered suitable for further analysis (cell count &amp;gt; 200 in carcinoma and stromal areas) with 2-3 cores per sample, resulting in a total of 441 tissue cores. The average cell count was 5732 per core (defined by positive nuclei stain). Stratification of samples into high or low expression was based on a median split of the positive cell fraction. Results: When investigating the number of PD1 and PD-L1 positive cells in the tumors (carcinoma and stroma combined), we observed that PD-1 expression significantly increased with tumor stage in pre- (p=0.002) and post-BCG (p=0.006) tumor samples. PD1 expression was also increased in high-grade tumors compared to low-grade tumors in pre-BCG samples (p = 0.001). Furthermore, we observed a significant association between tumors of higher stage and high PD-L1 expression in the pre-BCG samples (p = 0.007). Patients with low expression of PD1 and PD-L1 in the pre-BCG tumor samples had a superior high-grade recurrence-free survival (HG-RFS) compared to patients with high PD1 (p=0.002) and PD-L1 (p=0.021) expression. In addition, low expression of PD-L1 in pre-BCG tumors was correlated with a better progression-free survival compared to the patients with high PD-L1 expression (p = 0.013). Conclusion: Protein expression of PD1 and PD-L1 in pre-BCG tumor samples were correlated to higher stage and grade as well as worse HGFRS, indicating that T cell exhaustion plays an important role in resistance to BCG treatment. Citation Format: Tine G. Andreasen, Trine Strandgaard, Jørgen B. Jensen, Lars Dyrskjøt. High expression of the exhaustion markers PD1 and PD-L1 in non-muscle invasive bladder cancer is associated with poor outcome following Bacillus Calmette-Guérin immunotherapy [abstract]. In: Proceedings of the AACR Special Conference on Bladder Cancer: Transforming the Field; 2024 May 17-20; Charlotte, NC. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(10_Suppl):Abstract nr B008.

Ketogenic diet enhances the anti-cancer effects of PD-L1 blockade in renal cell carcinoma.

Clear cell renal cell carcinoma (ccRCC) is characterized by a predominant metabolic reprogramming triggering energy production by anaerobic glycolysis at the expense of oxydative phosphorylation. Ketogenic diet (KD), which consists of high fat and low carbohydrate intake, could bring required energy substrates to healthy cells while depriving tumor cells of glucose. Our objective was to evaluate the effect of KD on renal cancer cell tumor metabolism and growth proliferation. Growth cell proliferation and mitochondrial metabolism of ACHN and Renca renal carcinoma cells were evaluated under ketone bodies (KB) exposure. In vivo studies were performed with mice (nude or Balb/c) receiving a xenograft of ACHN cells or Renca cells, respectively, and were then split into 2 feeding groups, fed either with standard diet or a 2:1 KD ad libitum. To test the effect of KD associated to immunotherapy, Balb/c mice were treated with anti-PDL1 mAb. Tumor growth was monitored. In vitro, KB exposure was associated with a significant reduction of ACHN and Renca cell proliferation and viability, while increasing mitochondrial metabolism. In mice, KD was associated with tumor growth reduction and PDL-1 gene expression up-regulation. In Balb/c mice adjuvant KD was associated to a better response to anti-PDL-1 mAb treatment. KB reduced the renal tumor cell growth proliferation and improved mitochondrial respiration and biogenesis. KD also slowed down tumor growth of ACHN and Renca in vivo. We observed that PDL-1 was significantly overexpressed in tumor in mice under KD. Response to anti-PDL-1 mAb was improved in mice under KD. Further studies are needed to confirm the therapeutic benefit of adjuvant KD combined with immunotherapy in patients with kidney cancer.

Alterations in Peripheral Lymphocyte Subsets under Immunochemotherapy in Stage IV SCLC Patients: Th17 Cells as Potential Early Predictive Biomarker for Response.

UICC stage IV small-cell lung cancer (SCLC) is a highly aggressive malignancy without curative treatment options. Several randomized trials have demonstrated improved survival rates through the addition of checkpoint inhibitors to first-line platin-based chemotherapy. Consequently, a combination of chemo- and immunotherapy has become standard palliative treatment. However, no reliable predictive biomarkers for treatment response exist. Neither PD-L1 expression nor tumor mutational burden have proven to be effective predictive biomarkers. In this study, we compared the cellular immune statuses of SCLC patients to a healthy control cohort and investigated changes in peripheral blood B, T, and NK lymphocytes, as well as several of their respective subsets, during treatment with immunochemotherapy (ICT) using flow cytometry. Our findings revealed a significant decrease in B cells, while T cells showed a trend to increase throughout ICT. Notably, high levels of exhausted CD4+ and CD8+ cells, alongside NK subsets, increased significantly during treatment. Furthermore, we correlated decreases/increases in subsets after two cycles of ICT with survival. Specifically, a decrease in Th17 cells indicated a better overall survival. Based on these findings, we suggest conducting further investigation into Th17 cells as a potential early predictive biomarkers for response in patients receiving palliative ICT for stage IV SCLC.

Combination of plasma MMPs and PD-1-binding soluble PD-L1 predicts recurrence in gastric cancer and the efficacy of immune checkpoint inhibitors in non-small cell lung cancer.

The tumor microenvironment (TME) impacts the therapeutic efficacy of immune checkpoint inhibitors (ICIs). No liquid biomarkers are available to evaluate TME heterogeneity. Here, we investigated the clinical significance of PD-1-binding soluble PD-L1 (bsPD-L1) in gastric cancer (GC) patients and non-small cell lung cancer (NSCLC) patients treated with PD-1/PD-L1 blockade. We examined bsPD-L1, matrix metalloproteinases (MMPs), and IFN-γ levels in plasma samples from GC patients (n = 117) prior to surgery and NSCLC patients (n = 72) prior to and 2months after ICI treatment. We also examined extracellular matrix (ECM) integrity, PD-L1 expression, and T cell infiltration in tumor tissues from 25GC patients by Elastica Masson-Goldner staining and immunohistochemical staining for PD-L1 and CD3, respectively. bsPD-L1 was detected in 17/117GC patients and 16/72 NSCLC patients. bsPD-L1 showed strong or moderate correlations with plasma MMP13 or MMP3 levels, respectively, in both GC and NSCLC patients. bsPD-L1 expression in GC was associated with IFN-γ levels and intra-tumoral T cell infiltration, whereas MMP13 levels were associated with loss of ECM integrity, allowing tumor cells to access blood vessels. Plasma MMP3 and MMP13 levels were altered during ICI treatment. Combined bsPD-L1 and MMP status had higher predictive accuracy to identify two patient groups with favorable and poor prognosis than tumor PD-L1 expression: bsPD-L1+MMP13high in GC and bsPD-L1+(MMP3 and MMP13)increased in NSCLC were associated with poor prognosis, whereas bsPD-L1+MMP13low in GC and bsPD-L1+(MMP3 or MMP13)decreased in NSCLC were associated with favorable prognosis. Plasma bsPD-L1 and MMP13 levels indicate T cell response and loss of ECM integrity, respectively, in the TME. The combination of bsPD-L1 and MMPs may represent a non-invasive tool to predict recurrence in GC and the efficacy of ICIs in NSCLC.

Abstract PO5-06-09: Metastatic triple negative breast cancer has distinct tumor immune landscape

Abstract Background: Triple negative breast cancer (TNBC) is considered the most immunogenic breast cancer subtype due to higher levels of tumor infiltrating immune cells (TILS), elevated tumor mutational burden and PD-L1 expression, providing a rationale for immunotherapy. Here we aimed to investigate the differences in the immune microenvironment of primary vs. metastatic sites in TNBC vs. non-TNBC and their impact on survival. Methods: Comprehensive immune profiling, including PD-L1 IHC and the expression of 395 immune genes, was performed on 147 real-world FFPE breast cancer samples (32 primary, 115 metastatic). 37 samples were, by definition, triple negative for ER, PR, and HER2 overexpression. PD-L1 (CPS positive ≥1% and CPS positive ≥10%) was determined using immunohistochemistry (22C3). mRNA expression signatures of tumor inflammation (TIGS, weak/moderate/strong) and cell proliferation (CP, poor/moderate/high) were determined by RNA-sequencing. Demographic and clinicopathologic variables were collected. Statistical comparisons of biomarkers between groups were calculated using the Wilcoxon Rank-Sum test for continuous variables and the proportions test for categorical variables (p≤0.05 for significance). Survival differences were quantified by Cox proportional hazards analysis (p≤0.05 for significance). Results: Triple negative status was associated with current use of alcohol [p=0.03]. Black patients were also more likely to have TNBC, constituting 24% of TNBC patients while only making up 14% of the total cohort [p=0.04]. Conversely, white patients were less likely to have TNBC, constituting 73% of TNBC patients while making up 84% of the total cohort [p=0.04]. Comparing TNBC and non-TNBC cases, TNBC cases were observed to have significantly higher TIGS [p=0.014] and PD-L1 expression [p=4.4 × 10−7]. Additionally, TNBC cases trended towards exhibiting greater cell proliferation [p=0.069]. These differences were found to be driven primarily by metastatic tumors, among which TNBC tumors showed significantly higher TIGS [p=0.015], cell proliferation [p=0.021], and PD-L1 expression [p=2.9 × 10−7] than non-TNBC tumors, while none of these significant associations were observed among primary tumors. Triple negative status was significantly associated with PD-L1 expression (assessed by IHC), with a majority of PD-L1 positive cases determined to be triple negative [70% of CPS≥1% cases, p=5 × 10-5; 59% of CPS≥10% cases, p=6 × 10−4]. Several immune-related genes and immune checkpoint molecules were over-expressed in triple negative breast cancer, including CD8, GZMB, PRF1, CCL5, IFNG, TIGIT and CXCL10. A number of genes were also significantly overexpressed in metastatic tumors: KRT5 [p=0.02], TFRC [p=0.04], ABCF1 [p=0.04], FCRLA [p=0.05], LAMP3 [p=0.05], and underexpressed in metastatic tumors: ENTPD1 [p=0.05], IGSF6 [p=0.03], and ITGA1 [p=0.03]. Conclusions: Our comprehensive biomarker analyses showed that metastatic TNBC has a more inflamed tumor microenvironment and higher checkpoint target expression compared to non-TNBC. Further analysis of immune expression by site-specific metastases and correlation with immunotherapy outcomes is warranted to guide clinicians in selection of the ideal metastatic site to biopsy for therapeutic decision making. However, in a collective TNBC context, these data support the use of immunotherapy in metastatic TNBC. Citation Format: Robert Seager, Heidi Ko, Sarabjot Pabla, Maria-Fernanda Senosain, Erik Van Roey, Shuang Gao, Kyle Strickland, Rebecca Previs, Mary Nesline, Stephanie Hastings, Shengle Zhang, Jeffrey Conroy, Taylor Jensen, Marcia Eisenberg, Brian Caveney, Eric Severson, Shakti Ramkissoon, Shipra Gandhi. Metastatic triple negative breast cancer has distinct tumor immune landscape [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-06-09.

Abstract PO5-25-04: Predictive value of neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios in patients with triple negative breast cancer treated with pembrolizumab

Abstract Background: Immune checkpoint inhibitors (ICIs) offer new treatment possibilities for women with triple-negative breast cancer (TNBC) – one of the most challenging breast cancer subtypes. The PD-1 inhibitor pembrolizumab (pembro; Keytruda®) is approved in metastatic TNBC (mTNBC) patients with PD-L1(+) tumors, and for neoadjuvant treatment (NAT) in stage II/III TNBC [1, 2]. Residual cancer burden (RCB) after NAT is highly prognostic, with pathologic complete response (pCR, RCB 0) anticipating long-term survival [3]. In mTNBC, pembro plus chemotherapy in the 1st-line improves progression free survival (PFS), but durable responses are rare. Optimizing ICI use in TNBC thus remains an unmet need, and defining easily assessable markers of response is crucial. Neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are peripheral blood surrogates of tumor inflammation and have prognostic and predictive value in TNBC [4-8]. Elevated NLR (≥ 5) and PLR (≥ 200) correlate with worse outcomes upon ICIs in melanoma and non-small-cell lung cancer [9, 11-14]; however, this has not been studied in breast cancer [9, 10]. We evaluated the relationship of baseline NLR and PLR with pembro responses in TNBC patients. Methods: We retrospectively reviewed data from TNBC patients who completed pembro between 10/2/20 - 6/1/23 at Weill Cornell. Patients on NAT who did not complete treatment were excluded. RCB score (pCR/0, 1, 2, 3) was calculated from surgical resection pathology reports using the MD Anderson RCB Calculator [15, 16]. Baseline laboratory data were obtained from clinical records. Associations between NLR and PLR with RCB levels were examined using the non-parametric Kruskal-Wallis test (if &amp;gt;2 levels), the Wilcoxon rank sum test (if 2 levels), or the Spearman’s rank correlation. NLR and PLR were also correlated with PFS (measured from pembro start date to date of progression) in metastatic patients. PFS data for metastatic patients without interval imaging since pembro initiation were censored at the date of data analysis, and PFS was not calculated for patients who received only 1 cycle of pembro. Results: We identified 63 eligible patients: 24 were excluded due to lack of TNBC diagnosis (n=20), or because they only received adjuvant pembro (n=4). Of the 39 remaining patients, 5 did not complete NAT and 2 had missing data, leaving 32 evaluable patients (17 in the NAT cohort and 15 in the mTNBC cohort). Overall, the median age was 51 years, and 16% were Hispanic, 11% Asian, 57% non-Hispanic, 24% Black, and 65% Non-Black. Neoadjuvant cohort: The pCR rate was 30%. Patients with both NLR ≥ 5 and PLR ≥ 200, had a pCR rate of 0%; in patients with NLR &amp;lt; 5 or PLR &amp;lt; 200, pCR rate was 43%. Median NLR in pCR vs. non-pCR groups was 1.91 [IQR: 1.72- 2.73] vs. 2.44 [IQR: 1.97- 5.24] (p=0.3), with trends towards significance when NLR was compared between RCB levels &amp;gt;1 (2.67; IQR: 2.05, 6.49) vs. RCB levels ≤1 (1.91; IQR: 1.63, 2.58) (p=0.14). Mean PLR was higher in patients with RCB 2-3 (409) compared to those with pCR or RCB 1 (167) (p=0.146). Metastatic cohort: The overall mean PFS was 7.8 months. Visceral metastases were seen in 80% of patients (17% liver, 33% brain). In patients with brain mets, baseline NLR and PLR were higher than in the overall cohort (NLR, 4.86 vs. 2.78; PLR, 429 vs. 186). Conclusions: Our study is the first to evaluate NLR and PLR as response biomarkers in TNBC patients receiving pembro and is the first report of our real-world data of TNBC patients on pembro. In our neoadjuvant cohort, higher baseline NLR and PLR correlated with higher RCB levels, with a trend towards statistical significance. Further investigation and correlation of NLR and PLR with tumor microenvironment features will help to clarify these relationships. Citation Format: Ashley Schreier, Roberta Zappasodi, Inna Serganova, Laura Munoz Arcos, Xi Kathy Zhou, Massimo Cristofanilli, Eleni Andreopolu. Predictive value of neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios in patients with triple negative breast cancer treated with pembrolizumab [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-25-04.

Abstract GS01-02: Phase 3 study of neoadjuvant pembrolizumab or placebo plus chemotherapy, followed by adjuvant pembrolizumab or placebo plus endocrine therapy for early-stage high-risk ER+/HER2− breast cancer: KEYNOTE-756

Abstract Background: KEYNOTE-756 (NCT03725059) is a global phase 3 study of neoadjuvant pembrolizumab or placebo + chemotherapy followed by adjuvant pembrolizumab or placebo + endocrine therapy (ET) in patients with early-stage high-risk ER+/HER2– breast cancer. Here, we report primary pCR results and residual cancer burden (RCB) outcomes. Methods: Eligible patients with T1c-2 (≥2 cm) cN1-2 or T3-4 cN0-2, centrally confirmed, grade 3, invasive ductal ER+/HER2− breast cancer were randomized 1:1 to receive neoadjuvant pembrolizumab 200 mg Q3W or placebo, both given with paclitaxel QW for 12 weeks, then 4 cycles of doxorubicin or epirubicin + cyclophosphamide (neoadjuvant treatment). After definitive surgery (± radiation therapy), patients received pembrolizumab or placebo for 9 cycles + standard ET. Stratification factors include region (Eastern Europe, China, or Other), tumor PD-L1 status (CPS ≥1 [positive] vs CPS &amp;lt; 1 [negative]), nodal involvement (positive vs negative), ER positivity (≥10% vs &amp;lt; 10%) and anthracycline schedule (Q3W vs Q2W). Dual primary endpoints are pCR (ypT0/Tis ypN0) and EFS. Secondary endpoints include OS, pCR defined as ypT0 ypN0 and ypT0/Tis and safety. RCB was an exploratory endpoint and was assessed by a local pathologist at the time of surgery. RCB-0, -1, -2, and -3 denote increasingly larger residual disease. Results: 1278 patients were randomized to pembrolizumab + chemotherapy (n=635) or placebo + chemotherapy (n=643). At the final pCR analysis (May 25, 2023, first interim analysis data cutoff), median follow-up was 33.2 mo (range, 9.7-51.8). In the ITT population, pembrolizumab + chemotherapy showed a statistically significant improvement in pCR (ypT0/Tis ypN0) vs placebo + chemotherapy: 24.3% (95% CI, 21.0-27.8) vs 15.6% (95% CI, 12.8-18.6); estimated difference, 8.5 percentage points (95% CI, 4.2-12.8); P=0.00005; results were consistent for the secondary pCR definitions, ypT0 ypN0 (21.3% vs 12.8%) and ypT0/Tis (29.4% vs 18.2%). The benefit of pembrolizumab + chemotherapy on pCR was generally consistent in the prespecified subgroups. There were more patients with RCB-0 (24.7% vs. 15.6%) and RCB-1 (10.2% vs 8.1%) and fewer patients in the RCB-2 (40.8% vs. 45.3%) and RCB-3 categories (20.5% vs. 28.9%) in the pembrolizumab group versus the placebo group. In the neoadjuvant phase, grade ≥3 treatment-related AE rates were 52.5% with pembrolizumab + chemotherapy and 46.4% with placebo + chemotherapy, with 1 death in the pembrolizumab arm due to acute myocardial infarction. EFS results are still immature and continue to be evaluated. Conclusions: The addition of pembrolizumab to chemotherapy significantly increased the pCR rate and shifted RCB to lower residual disease categories in patients with early-stage high-risk ER+/HER2− breast cancer. Safety was consistent with the known profiles of each regimen. Citation Format: Fatima Cardoso, Joyce O'Shaughnessy, Heather McArthur, Peter Schmid, Javier Cortés, Nadia Harbeck, Melinda Telli, David Cescon, Peter A. Fasching, Zhimin Shao, Delphine Loirat, Yeon Hee Park, Manuel Gonzalez Fernandez, Gabor Rubovszky, Seock-Ah Im, Rina Hui, Toshimi Takano, Fabrice André, Hiroyuki Yasojima, Zhenzhen Liu, Yu Ding, Liyi Jia, Vassiliki Karantza, Konstantinos Tryfonidis, Aditya Bardia. Phase 3 study of neoadjuvant pembrolizumab or placebo plus chemotherapy, followed by adjuvant pembrolizumab or placebo plus endocrine therapy for early-stage high-risk ER+/HER2− breast cancer: KEYNOTE-756 [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr GS01-02.

Abstract PO1-25-03: Programmed Death-Ligand 1 and Receptor Tyrosine Kinases in Breast Cancer

Abstract Programmed death-ligand 1 (PD-L1) is an immune checkpoint expressed in a wide range of malignancies leading to immune tolerance and cancer cell immune evasion. Receptor tyrosine kinases (RTKs) are key regulators of cancer cell proliferation, survival, and invasion. The Hepatocyte Growth Factor (HGF) receptor, MET, and the Epidermal Growth Factor Receptor (EGFR) are RTKs known for their tumorigenic potential in a variety of human malignancies. This study aimed to evaluate the effect of the small-molecule tyrosine kinase inhibitors (TKIs) on the expression of PD-L1 in breast cancer cells and the effect of their combination with inflammatory cytokines. The study also assessed the association of the expression of the tumoral PD-L1 mRNA with each of MET and EGFR mRNA expression and the tumor features and treatment outcomes in breast cancer patients using the METABRIC dataset publicly available from cBioPortal for Cancer Genomics. The TKIs crizotinib [a MET inhibitor] and gefitinib [an EGFR inhibitor] were used as a single treatment and in combination with the cytokines; tumor necrosis factor-α (TNF-α) or interferon-γ (INF-γ) in MCF7 and MDA-MB-231 breast cancer cells in vitro. The cells were also treated with the mitogens HGF and EGF. The viability of cells after the different treatments was determined using the MTT viability assay. The effects of the combination treatments were analyzed using combination index (CI) analysis. The expression level of PD-L1 in cancer cells was assessed using Western blotting. The combination treatment of crizotinib with TNF-α and INF-γ produced a synergistic growth inhibition of MCF7 and MDA-MB-231 cells with CI values of 0.31 and 0.55, respectively. Alternatively, combined crizotinib and TNF-α produced an antagonist effect on the viability of MCF7 cells (CI=2.49). The combination of gefitinib with TNF-α produced a synergistic growth inhibition in both MCF7 and MDA-MB-231 cells with CI values of 0.39 and 0.78, respectively. Alternatively, gefitinib resulted in an additive effect when combined with INF-γ (CI=0.99) and an antagonistic effect when combined with TNF-α (CI=2.68) in MCF7 and MDA-MB-231 cells, respectively. Treatment with HGF (50 and 100 ng/ml) increased the protein levels of PD-L1 while EGF (50 and 100 ng/ml) reduced its levels in MDA-MB-231 cells. Treatment with the TKIs crizotinib (0.1-4 µM) and gefitinib (1-40 µM) significantly reduced PD-L1 levels in MDA-MB-231 cells compared to vehicle-treated cells. The analysis of the METABRIC dataset revealed that the mRNA expression of PD-L1 was positively correlated with the mRNA expression of the EGFR gene (r= 0.081, p&amp;lt; 0.001) but not the MET gene. A double-high PD-L1/MET expression was significantly associated with younger age at diagnosis, high-grade carcinoma, greater tumor size, hormone receptor-negative status, HER2-positivity, and non-luminal disease compared to patients with a double-low PD-L1/MET expression. Similar findings were reported for patients with a double-high PD-L1/EGFR expression compared to patients with a double-low PD-L1/EGFR expression. Nevertheless, the mRNA expression of the PD-L1, MET, and EGFR genes as well as the co-expression of PD-L1/MET or PD-L1/EGFR genes did not affect the overall survival of breast cancer patients. Collectively, MET and EGFR TKIs could modulate the effects of inflammatory cytokines differently based on the type of cytokine and the molecular subtype of breast cancer cells. The expression of PD-L1 in breast cancer cells was upregulated by HGF while TKIs reduced its expression. The co-expression of the PD-L1 gene with MET and EGFR genes in breast cancer was associated with advanced disease presentation and worse prognosticators in patients. Together, TKIs that target MET or EGFR could be an appealing therapeutic target in breast cancer, particularly in younger patients with the non-luminal disease. Citation Format: Nehad Ayoub, Muhsen Al-Diabat, Moath Al-Shorman, Laith Al-Eitan. Programmed Death-Ligand 1 and Receptor Tyrosine Kinases in Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-25-03.

Abstract GS01-05: Pembrolizumab + Olaparib vs Pembrolizumab + Chemotherapy After Induction With Pembrolizumab + Chemotherapy for Locally Recurrent Inoperable or Metastatic TNBC: Randomized Open-Label Phase 2 KEYLYNK-009 Study

Abstract Background: Pembrolizumab (pembro) plus chemotherapy (chemo) showed statistically significant improvements in PFS and OS vs placebo + chemo in patients (pts) with previously untreated locally recurrent inoperable or metastatic triple-negative breast cancer (TNBC) whose tumors expressed PD-L1 with a combined positive score (CPS) ≥10 in the phase 3 KEYNOTE-355 study. Tolerable and effective maintenance regimens after induction therapy are needed to sustain clinical benefit. The PARP inhibitor olaparib is an established maintenance therapy for multiple platinum-sensitive tumor types and prior data suggest that PARP inhibitors combined with PD-1/PD-L1 inhibitors could provide an improved therapeutic effect. KEYLYNK-009 (NCT04191135) is a randomized open-label phase 2 study to evaluate the efficacy and safety of maintenance pembro + olaparib vs pembro + chemo in pts with locally recurrent inoperable or metastatic TNBC who had clinical benefit from induction with 1L pembro + platinum-based chemo. Methods: Eligible pts with measurable, locally recurrent inoperable or metastatic TNBC that had not been previously treated with chemo in the metastatic setting received induction therapy for up to 6 cycles of pembro 200 mg + chemo (carboplatin AUC 2 + gemcitabine 1000 mg/m2 on days 1 and 8) every 3 wk (Q3W). Pts with complete response (CR), partial response (PR), or stable disease (SD) after 4-6 treatment cycles were randomized 1:1 to receive pembro 200 mg Q3W + olaparib 300 mg twice daily or pembro + chemo (continued induction regimen). Olaparib or chemo was continued until progression or unacceptable toxicity; pembro was continued for up to 35 cycles (including induction treatment), progression, or unacceptable toxicity. Pts were stratified by induction response (CR or PR vs SD, by RECIST v1.1), tumor PD-L1 status (CPS ≥1 vs CPS &amp;lt; 1), and tumor genomic status (tBRCAm vs tBRCAwt). Dual primary endpoints were PFS per RECIST v1.1 by BICR and OS from randomization in all pts. Secondary endpoints included PFS and OS from randomization in pts with PD-L1 CPS ≥10 tumors and in pts with tBRCAm, and safety. Results: Of the 460 pts who received induction therapy, 271 were randomly assigned to pembro + olaparib (n=135) or pembro + chemo (n=136). At the Dec 15, 2022 data cutoff, median follow-up was 17.2 mo. Maintenance pembro + olaparib did not significantly improve PFS or OS vs pembro + chemo after induction therapy (Table). Median PFS was longer with pembro + olaparib vs pembro + chemo in pts with tBRCAm, but not in pts with PD-L1 CPS ≥10 tumors; a similar trend was observed for OS (Table). In 268 treated pts, treatment-related AEs (TRAEs) occurred in 114 of 135 pts (84.4%) for pembro + olaparib and in 128 of 133 pts (96.2%) for pembro + chemo. Grade ≥3 TRAEs occurred in 44 pts (32.6%) for pembro + olaparib (0 deaths) and in 91 pts (68.4%) for pembro + chemo (2 [1.5%] deaths), with 12 (8.9%) vs 26 (19.5%) discontinuations for TRAEs, respectively. Conclusions: The primary endpoints of PFS and OS were not met in an unselected population of pts with advanced TNBC. However, directionally favorable improvements in PFS and OS were observed in pts with tBRCAm with pembro + olaparib vs pembro + chemo, representing a potential maintenance strategy. Further data are required to confirm this effect. No new safety signals were observed, and there were fewer TRAEs in the pembro + olaparib group vs the pembro + chemo group. PFS and OS were evaluated from the time of randomization. *Based on stratified Cox regression model with Efron’s method of tie-handling with treatment as a covariate. NR = not reached. Citation Format: Hope Rugo, Mark Robson, Seock-Ah Im, Florence Dalenc, Eduardo Yañez Ruiz, Young-Hyuck Im, Sergii Kulyk, Oleksandr Dudnichenko, Néstor Llinás-Quintero, Shigehira Saji, Yasuo Miyoshi, Nadia Harbeck, Li Fan, Jaime Mejia, Vassiliki Karantza, David Cescon. Pembrolizumab + Olaparib vs Pembrolizumab + Chemotherapy After Induction With Pembrolizumab + Chemotherapy for Locally Recurrent Inoperable or Metastatic TNBC: Randomized Open-Label Phase 2 KEYLYNK-009 Study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr GS01-05.

Abstract PO2-23-12: Innovative Metastatic Breast Cancer Therapy, CBT300, Reverses Drug and Immune Resistance

Abstract For many patients with metastatic breast cancer (MBC), their disease is treatable but incurable. Although the rate of death from MBC has significantly decreased over the last 10 years due to early detection and new treatment options, MBC still accounts for over 40,000 deaths each year in the US that has been consistent for the past 30 years. Recently, it is estimated that 90% of those deaths were due to drug resistant recurrent disease. Nearly 45% of MBC deaths can be attributed to a subpopulation of patients with metastatic triple negative breast cancer (mTNBC). Despite MBC’s initial sensitivity to chemotherapy, it often recurs at greater than 40% in stage I-III patients and greater than 80% in stage IV patients which have a dismal 5-year survival of 12%. African American women have a 40% greater incidence of death from MBC despite a 4% lower risk of diagnosis. Unfortunately, current therapies do little to reduce drug resistance and death for recurrent drug resistant MBC. Currently, the only therapies approved by the FDA for recurrent TNBC patients are Keytruda plus chemotherapy and an Antibody Drug Conjugate (ADC) called Sacituzumab Govitecan. Keytruda (anti-PD-L1) is an immune checkpoint inhibitor(ICI) given with chemotherapy (nab-paclitaxel, paclitaxel, or gemcitabine plus carboplatin). The second recently approved therapy, Sacituzumab Govitecan (SG), is composed of an antibody to human trophoblast cell-surface antigen 2 (Trpo-2) coupled to SN-38 (topoisomerase I inhibitor). Although these results are very encouraging, the 80% of TNBC patients that either do not have high positive PD-L1 tumors, or don’t respond to these therapies and become drug resistant suggests that most patients with TNBC will have recurrent disease with little or no hope for survival. For contrast, our novel MBC therapy, CBT300, targets cell surface GRP78 that has been found in over 95% of MBC and in 93% of TNBC tumors. We can now show that inhibition of cell surface GRP78 can a) induce apoptosis of drug resistant TNBC cells in vitro and in vivo, b) eliminate drug resistance showing synergistic effects with chemotherapy in vitro and in vivo, c) decrease amount of chemotherapy in combination with CBT300 and d) reduce immune suppression. Recent publications show that GRP78 is found on many types of tumor cell surfaces but not on normal cell surfaces. In fact, tumor cell surface GRP78 (csGRP78) is important for many aspects of MBC development, including cell survival, proliferation, chemoresistance, angiogenesis, metastasis formation, immune suppression, and stem cell formation. Recently, it has been shown that increased cell surface GRP78 expression in TNBC patients was significantly associated with later stage, increased distant metastasis, increased aggressiveness, shorter disease-free survival, and decreased overall survival. In studies to help understand how cell surface GRP78 causes MBC progression and drug resistance, we discovered a novel GRP78 binding transmembrane protein on TNBC cells called Receptor Tyrosine Kinase Orphan Receptor-1 (ROR1). Using the GRP78 binding domain from ROR1 and a human Fc IgG1 domain, we created a biologic fusion protein that is a potent and cell surface specific GRP78 inhibitor, CBT300. We now show that CBT300’s elimination of cell surface GRP78 destabilizes and removes oncofetal proteins ROR1, Cripto-1, and checkpoint protein PD-L1 from tumor cell surfaces resulting in reversal of chemoresistance, reduction in immune suppression, inhibition of stem cell phenotype and increased tumor cell apoptosis. Since ROR1, Cripto-1 and PD-L1 are three of the major redundant pathways for tumor drug resistance, immune suppression and stem cell formation, the ability to inhibit all these pathways with CBT300, a single safe and very efficacious therapy, is very innovative and could be a significant advance for the treatment of MBC. Citation Format: Elizabeth Stolarik, Jorryn Zelek, Mariah Thigpen, Anita Davidson, Donald Davidson. Innovative Metastatic Breast Cancer Therapy, CBT300, Reverses Drug and Immune Resistance [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-23-12.

Abstract PO1-18-07: Phase I trial of combination pembrolizumab and ruxolitinib in metastatic triple negative breast cancer

Abstract BACKGROUND: The amplification of genes PDL-1, PDL-2, and JAK2 on chromosome 9p24, known as the PDJ amplicon, has been identified in 15% of triple negative breast cancer (TNBC) and is associated with tumor infiltrating lymphocytes and elevated JAK2 mRNA, suggesting a coordinated inflammatory response in TNBC. Adding pembrolizumab to chemotherapy in KEYNOTE trials 355 and 522 has validated the use of PD-1 blockade in TNBC and redefined the standard of care. Despite preclinical data suggesting a role for targeting the IL- 6/JAK2/STAT3 pathway, the JAK1/JAK2 inhibitor ruxolitinib has not shown efficacy as a single Agent in breast cancer. This is the first phase I clinical trial evaluating the combination of pembrolizumab and ruxolitinib in the treatment of metastatic TNBC. METHODS: We conducted a phase I clinical trial with accrual from 2018 to 2023 at Mayo Clinic Arizona. Patients (n=12) received 200 mg of IV pembrolizumab per cycle (every 3 weeks) with 3+3 dose escalation of oral ruxolitinib twice a day (dose level 0: 10 mg PO BID, level 1: 15 mg PO BID, level 2: 20 mg PO BID). The primary endpoint was to determine the maximum tolerated dose (MTD) of ruxolitinib and secondary endpoints were treatment safety and efficacy. Clinical response was assessed by computed tomography of the chest, abdomen, and pelvis every 3 cycles. PD-L1 expression in tumor was measured by immunohistochemistry (IHC). The effect of the combined therapies on T and B cell populations were assessed by flow cytometry and antibody profiling of 695 tumor antigens and 8 viral antigens by nucleic acid protein programmable array. RESULTS: Twelve female patients with chemotherapy refractory metastatic TNBC were treated on study. All received 200 mg IV pembrolizumab every cycle. Due to rapid disease progression of three patients early after treatment initiation, eligibility was restricted to prohibit patients with extensive pulmonary disease or elevated LDH. Those patients were excluded from efficacy or correlative analysis. The most common toxicities were transaminitis (n=12), anemia/leukopenia (n=12), and fatigue (n=9). The majority of adverse events were grade 1 and occurred at dose level 2. There were 5 adverse events grade 3 or higher: respiratory or thoracic complications (n=3), hypertension (n=1), and abdominal pain (n=1), but MTD was not established. The median number of cycles was 4 for each dose level (range n=2.0-9.0) and the median time to progression was 3 months (range n=1.4-6.3). No patient had tumor response by RECIST v1.1 criteria and there was no association of disease stability with PD-L1 tumor expression by IHC. Circulating antibodies to tumor antigens remained stable, and viral-specific antibodies mildly decreased by month 2 in all patients at dose levels 0 and 1. Of the 7 patients reactive to TRIM21 autoantibodies, 2 patients had a transient increase at 2 months. CONCLUSIONS: The combination of pembrolizumab with ruxolitinib was well tolerated at all dose levels, and the number but not the severity of adverse events increased with higher ruxolitinib dose. Two of six patients in dose level 0 and 1 had stable disease for six months on treatment, suggesting that the lower dose levels of ruxolitinib (i.e. 10 mg PO BID) may have more activity in combination with pembrolizumab. Citation Format: Anelia Kassi, Jacqueline Carmona, Sarah M. Green, Heidi Kosiorek, Michael T. Barrett, Barbara A. Pockaj, Donald Northfelt, Karen S. Anderson. Phase I trial of combination pembrolizumab and ruxolitinib in metastatic triple negative breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-18-07.

B cell-intrinsic IL-27 and IFNγ receptor signaling drive PD-L1 expression, IgG2a autoantibody production, VEGF-dependent tumor angiogenesis and cancer progression

Abstract B effector cells produce Abs and autoantibodies, while B regulatory cells use cytokines and transmembrane proteins to fine tune immune functions. Our lab recently revealed that tumor-infiltrating B cells produce IL-27 to promote immune evasion, partly by upregulating tumoral PD-L1, including that expressed by B cells per se. To investigate the autocrine activity of IL-27 in tumor progression, we generated μMT:Il27ra–/– bone marrow chimera mice lacking the IL-27 receptor specifically in B cells. These mice displayed substantially reduced tumor growth from orthotopically engrafted ER+ E0771 breast cancer cells, as associated with only moderately decreased PD-L1 levels but, unexpectedly, severely compromised blood vessel integrity. The residual PD-L1 levels and tumor growth were virtually abolished by additional B cell-specific deficiency in IFNγ receptor signaling, as occurring in double KO μMT:Il27ra–/–Ifngr1–/– mice, in which the microvessel permeability was also worsened. Mechanistically, this aligned with our findings that IL-27-producing B cells expressed high levels of VEGFA, whose transcription in activated B cells could be further enhanced by IL-27 and IFNγ. Double KO mice also lacked anti-dsDNA IgG2a autoantibodies, as elicited by tumor engraftment. Thus, B cell-intrinsic IL-27 and IFNγ receptor signaling synergize to promote B-cell PD-L1 expression, IgG2a autoantibody production, and vascular integrity, all of which may contribute to cancer development.

Comparative efficacy of immune checkpoint inhibitors combined with chemotherapy in patients with advanced driver-gene negative non-small cell lung cancer: A systematic review and network meta-analysis

ObjectiveTo evaluate the efficacy of different combinations of immune checkpoint inhibitors (ICIs) and chemotherapy (CT) in the treatment of advanced non-small cell lung cancer (NSCLC). MethodsWe obtained relevant randomized controlled trials (RCTs) from databases such as PubMed, Embase, Web of Science, and The Cochrane Library up to May 31, 2023. The analysis of clinical prognostic factors was performed using R 4.2.3 and STATA 15.0. The main outcomes measured were overall survival (OS) and progression-free survival (PFS), while secondary outcomes included the objective response rate (ORR), disease control rate (DCR), and treatment-related adverse events of grade 3–5 severity (Grade ≥3 TRAE). ResultsA total of 17 randomized controlled trials (RCTs) were conducted between 2012 and 2023, involving 7792 patients. These trials evaluated 11 different treatment methods. The results of these trials showed that in terms of overall survival (OS) and progression-free survival (PFS), the combination of tislelizumab with chemotherapy and the combination of camrelizumab with chemotherapy were particularly effective. Moreover, when compared with other combination therapies, pembrolizumab combined with chemotherapy showed superiority in terms of disease control rate (DCR) and objective response rate (ORR). Subgroup analyses further demonstrated that the addition of immune checkpoint inhibitors (ICIs) to chemotherapy significantly improved PFS and OS in patients without liver metastasis and in those with brain metastasis. Additionally, carboplatin-based combination therapy was found to confer favorable survival benefits in terms of PFS, while cisplatin-based combination therapy showed the most favorable outcomes in terms of OS. The results of subgroup analyses for overall survival (OS) showed that the combination of immunotherapy and chemotherapy yielded positive outcomes in specific subgroups. These subgroups were characterized by PD-L1 Tumor Proportion Score (TPS) of 50 % or higher, usage of anti-PD-1 medications, age below 65, male gender, smoking history, and non-squamous cell carcinoma histology. Superior effectiveness was demonstrated only in extending the progression-free survival (PFS) of female patients and patients with squamous carcinoma. Meanwhile, other patient cohorts did not show the same level of improvement. ConclusionsTislelizumab, camrelizumab or pembrolizumab combined with chemotherapy may be the optimal first-line treatment strategies for NSCLC.

Clinical Validation of Artificial Intelligence-Powered PD-L1 Tumor Proportion Score Interpretation for Immune Checkpoint Inhibitor Response Prediction in Non-Small Cell Lung Cancer.

Evaluation of PD-L1 tumor proportion score (TPS) by pathologists has been very impactful but is limited by factors such as intraobserver/interobserver bias and intratumor heterogeneity. We developed an artificial intelligence (AI)-powered analyzer to assess TPS for the prediction of immune checkpoint inhibitor (ICI) response in advanced non-small cell lung cancer (NSCLC). The AI analyzer was trained with 393,565 tumor cells annotated by board-certified pathologists for PD-L1 expression in 802 whole-slide images (WSIs) stained by 22C3 pharmDx immunohistochemistry. The clinical performance of the analyzer was validated in an external cohort of 430 WSIs from patients with NSCLC. Three pathologists performed annotations of this external cohort, and their consensus TPS was compared with AI-based TPS. In comparing PD-L1 TPS assessed by AI analyzer and by pathologists, a significant positive correlation was observed (Spearman coefficient = 0.925; P < .001). The concordance of TPS between AI analyzer and pathologists according to TPS ≥50%, 1%-49%, and <1% was 85.7%, 89.3%, and 52.4%, respectively. In median progression-free survival (PFS), AI-based TPS predicted prognosis in the TPS 1%-49% or TPS <1% group better than the pathologist's reading, with the TPS ≥50% group as a reference (hazard ratio [HR], 1.49 [95% CI, 1.19 to 1.86] v HR, 1.36 [95% CI, 1.08 to 1.71] for TPS 1%-49% group, and HR, 2.38 [95% CI, 1.69 to 3.35] v HR, 1.62 [95% CI, 1.23 to 2.13] for TPS <1% group). PD-L1 TPS assessed by AI analyzer correlates with that of pathologists, with clinical performance also being comparable when referenced to PFS. The AI model can accurately predict tumor response and PFS of ICI in advanced NSCLC via assessment of PD-L1 TPS.

Combination treatment with PD1/PDL-1 inhibitors for sarcomas: state of the art, next questions.

Only a small fraction of sarcomas exhibit recognized parameters of immune sensitivity, such as tumor mutational burden, PDL-1 expression, or microsatellite instability. Combined strategies aimed to modulate tumor microenvironment to increase the efficacy of PD1/PDL-1 inhibitors in sarcoma. Most explored prospective studies were based on combinations of PD1/PDL-1 inhibitors with antiangiogenics, other immune checkpoints, or chemotherapy. Results on 6-month PFS rate, median PFS, and ORR in trials using PD1/PDL-1 inhibitors plus antiangiogenics ranged respectively as 46.9-55%, 4.7-7.8 months and 21-36.7%. In combination with other immune checkpoint inhibitors, the results of median PFS and ORR ranged from 2.8-4.1 months and 10-16%, respectively. In combination with chemotherapy, the best results were obtained with doxorubicin-based regimens compared to other agents. Duplet-based chemotherapy plus anti-PD1/PDL-1 obtained the highest ORR (56.2%) compared with doxorubicin (19-36.7%). Currently, the most robust predictive biomarker for anti-PD1/PDL-1 efficacy is the presence of tertiary lymphoid structures (TLS) with mature dendritic cells. Even when direct comparisons between PD1/PDL-1 inhibitor-based combinations and single agents have not been performed yet in sarcoma, some combinations appear promising. Studies controlling heterogeneity by biomarker or histotype selection contribute to an increase in efficacy or knowledge crucial for future comparative trials.

Arsenic trioxide augments immunogenic cell death and induces cGAS-STING-IFN pathway activation in hepatocellular carcinoma

The treatment of hepatocellular carcinoma (HCC) is particularly challenging due to the inherent tumoral heterogeneity and easy resistance towards chemotherapy and immunotherapy. Arsenic trioxide (ATO) has emerged as a cytotoxic agent effective for treating solid tumors, including advanced HCC. However, its effectiveness in HCC treatment remains limited, and the underlying mechanisms are still uncertain. Therefore, this study aimed to characterize the effects and mechanisms of ATO in HCC. By evaluating the susceptibilities of human and murine HCC cell lines to ATO treatment, we discovered that HCC cells exhibited a range of sensitivity to ATO treatment, highlighting their inherent heterogeneity. A gene signature comprising 265 genes was identified to distinguish ATO-sensitive from ATO-insensitive cells. According to this signature, HCC patients have also been classified and exhibited differential features of ATO response. Our results showed that ATO treatment induced reactive oxygen species (ROS) accumulation and the activation of multiple cell death modalities, including necroptosis and ferroptosis, in ATO-sensitive HCC cells. Meanwhile, elevated tumoral immunogenicity was also observed in ATO-sensitive HCC cells. Similar effects were not observed in ATO-insensitive cells. We reported that ATO treatment induced mitochondrial injury and mtDNA release into the cytoplasm in ATO-sensitive HCC tumors. This subsequently activated the cGAS-STING-IFN axis, facilitating CD8+ T cell infiltration and activation. However, we found that the IFN pathway also induced tumoral PD-L1 expression, potentially antagonizing ATO-mediated immune attack. Additional anti-PD1 therapy promoted the anti-tumor response of ATO in ATO-sensitive HCC tumors. In summary, our data indicate that heterogeneous ATO responses exist in HCC tumors, and ATO treatment significantly induces immunogenic cell death (ICD) and activates the tumor-derived mtDNA-STING-IFN axis. These findings may offer a new perspective on the clinical treatment of HCC and warrant further study.

High serum sodium predicts immunotherapy response in metastatic renal cell and urothelial carcinoma

ObjectivesThe development of reliable biomarkers for the prediction of immune checkpoint inhibition (ICI) response in patients with metastatic renal cell carcinoma (mRCC) and urothelial carcinoma (mUC) remains an unresolved challenge. Conventional ICI biomarkers typically focus on tumor-related factors such as PD-L1 expression. However, a comprehensive evaluation of the predictive value of serum electrolyte levels, a so far widely unexplored area, is still pending. MethodsWe conducted a post-hoc analysis of baseline sodium, potassium, chloride, magnesium and calcium levels in two independent phase 3 clinical trials: IMvigor211 for mUC comparing atezolizumab to chemotherapy, and IMmotion151 for mRCC comparing atezolizumab+bevacizumab to sunitinib. This analysis aimed to evaluate the prognostic and predictive value of these electrolyte levels in these clinical settings. A total of 1787 patients (IMvigor211 n = 901; IMmotion151 n = 886) were analyzed. ResultsWe found a linear correlation of baseline serum sodium and chloride with prognosis across both trials, which was not found for potassium, magnesium and calcium. In multivariate analysis, the prognostic capacity of sodium was limited to patients receiving ICI as compared to the control group. Interestingly, in both studies, the chance of achieving an objective response was highest in the patient subgroup with high baseline serum sodium levels of > 140 mmol/L (IMmotion151: Complete response in 17.9% versus 2.0% in patients with mRCC with baseline sodium < 135 mmol/L). Serum sodium outperformed tumor PD-L1 expression as a predictor for immunotherapy efficacy. ConclusionsPatients exhibiting elevated serum sodium levels derive the greatest benefit from immunotherapy, suggesting that baseline serum concentration could serve as a valuable and cost-effective predictive biomarker for immunotherapy across entities.