Programmed Cell Death-1 Blockade Therapy Research Articles

Abstract CT211: Safety of prompt initiation of durvalumab or STRIDE (single tremelimumab regular interval durvalumab) regimen as hepatocellular carcinoma (HCC) treatment for patients with chronic active hepatitis B

Abstract Background: Chronic hepatitis B is an etiology of HCC. Clinical trials using immune checkpoint inhibitors (ICIs) as HCC treatment typically exclude patients with chronic active hepatitis B (serum hepatitis B virus [HBV] viral load > 2000 IU/mL) or require the HBV viral load to be below a certain level using anti-HBV medications. In the phase 3 HIMALAYA study, the STRIDE regimen was superior to sorafenib and durvalumab was noninferior to sorafenib in overall survival benefits. This study explored the safety of concurrent administration of STRIDE or durvalumab with anti-HBV mediations for patients with chronic, active hepatitis B infection. Methods: We enrolled patients with advanced HCC, Child-Pugh A liver function reserve, and chronic active hepatitis B not under anti-HBV treatment. Initially, only patients naïve to ICIs were eligible, and patients received durvalumab 1500mg iv every 4 weeks until disease progression, occurrence of unacceptable toxicities, or the maximum treatment duration of 2 years. After the positive results of the HIMALAYA study, we added tremelimumab 300mg iv on D1 following the STRIDE regimen and allowed enrollment of patients who had received prior programmed cell death-1 blockade therapy. Patients initiated entecavir as HBV treatment within 7 days of starting ICI therapy. The plan was to enroll 30 patients, with the primary outcome of HBV reactivation (a ≥2 log increase in serum HBV DNA compared to the baseline level). Results: The study is still ongoing and as of 31 Aug 2023, 19 patients were enrolled. Two patients were female, and the median age was 65.5 years. Ten patients received durvalumab alone, and 9 received the STRIDE regimen. The ALBI grade was 1 and 2 in 3 (16%) and 16 (84%) patients, respectively. Macrovascular invasion and extrahepatic spread were present in 11 (58%) and 11 (58%) patients, respectively; 12 (63%) patients had alpha-fetoprotein level ≥ 400 ng/mL. Eleven (58%) patients had received prior systemic therapy for HCC, such as sorafenib (n = 9), lenvatinib (n = 5), and regorafenib (n = 4). The mean±standard deviation baseline HBV viral load was 1.18±0.44 mIU/mL. With the median follow-up on 6.1 months, no patients experienced HBV reactivation or HBV-associated hepatitis. Hepatitis flare (ALT increase to ≥3 times the baseline level) was noted in 4 (21%) patients, but none were considered HBV-associated. The best objective tumor response was complete and partial response in 0 and 5 (26.3%) patients, respectively, and the disease control rate was 63.2%. Conclusion: In the preliminary results, simultaneous initiation of immunotherapy and anti-HBV medications in patients with HCC and chronic active hepatitis B did not increase HBV reactivation rate. This study was supported by AstraZeneca (NCT04294498). Citation Format: Yu-Yun Shao, Ching-Tso Chen, Tsung-Che Wu, Tsung-Hao Liu, Chien-Huai Chuang, Ann-Lii Cheng, Chih-Hung Hsu. Safety of prompt initiation of durvalumab or STRIDE (single tremelimumab regular interval durvalumab) regimen as hepatocellular carcinoma (HCC) treatment for patients with chronic active hepatitis B [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT211.

Neoadjuvant-Adjuvant vs Neoadjuvant-Only PD-1 and PD-L1 Inhibitors for Patients With Resectable NSCLC

Neoadjuvant therapy combining programmed cell death 1 (PD-1) and programmed death ligand 1 (PD-L1) inhibitors with platinum-based chemotherapy has demonstrated significant improvement in pathologic response and survival rates among patients with resectable non-small cell lung cancer (NSCLC). However, it remains controversial whether PD-1 blockade therapy given before and after surgery (neoadjuvant-adjuvant treatment) is associated with better outcomes than when given only before surgery (neoadjuvant-only treatment). To compare the efficacy and safety associated with neoadjuvant-adjuvant anti-PD-1 and anti-PD-L1 therapy with neoadjuvant-only anti-PD-1 and anti-PD-L1 therapy for patients with resectable NSCLC. A systematic search was conducted across databases including PubMed, Embase, and the Cochrane Library, as well as major oncology conferences, through July 31, 2023. Randomized clinical trials comparing neoadjuvant-adjuvant or neoadjuvant-only PD-1 and PD-L1 inhibitor therapy vs chemotherapy alone for patients with resectable NSCLC were selected. Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline, 2 authors independently extracted data. Hazard ratios (HRs) and 95% CIs for event-free survival (EFS) and overall survival (OS) were extracted and then pooled through the generic inverse-variance methods. Relative risks (RRs) for treatment-related adverse events (TRAEs) were derived via the Mantel-Haenszel method. Using chemotherapy as a common comparator, indirect comparisons between neoadjuvant-adjuvant immunotherapy and neoadjuvant-only immunotherapy were conducted using frequentist methods. A random or fixed model was used based on intertrial heterogeneity identified through the Cochran Q test. The primary outcome was EFS, with secondary outcomes including OS and TRAEs. The study encompassed 4 trials of neoadjuvant-adjuvant immunotherapy and 1 trial of neoadjuvant-only immunotherapy, involving 2385 patients. Direct meta-analysis revealed significant improvements in EFS for both neoadjuvant-adjuvant and neoadjuvant-only immunotherapy compared with chemotherapy alone. In indirect meta-analysis, the addition of adjuvant immunotherapy to neoadjuvant immunotherapy was not associated with improved EFS (HR, 0.90; 95% CI, 0.63-1.30; P = .59) or OS (HR, 1.18; 95% CI, 0.73-1.90; P = .51) compared with neoadjuvant-only immunotherapy. Moreover, the incidence of any grade of TRAEs significantly increased with the addition of adjuvant immunotherapy (RR, 1.08; 95% CI, 1.00-1.17; P = .04). This meta-analysis suggests that adding PD-1 or PD-L1 inhibitors in the adjuvant phase to neoadjuvant treatment with PD-1 or PD-L1 inhibitors and chemotherapy may not improve survival outcomes for patients with resectable NSCLC and may be associated with increased adverse events. Future validation of these findings is warranted through head-to-head randomized clinical trials.

Impact of prophylactic dexamethasone on the efficacy of immune checkpoint inhibitors plus platinum-based chemotherapy in patients with advanced Non-Squamous Non-Small-Cell lung cancer

BackgroundBaseline corticosteroids exposure is associated with inferior clinical outcomes in patients with non-small-cell lung cancer (NSCLC) treated with programmed cell death-1 (PD-1) axis blockade. Dexamethasone is a potent corticosteroid used in the prevention of chemotherapy-associated adverse events (CAAEs). ObjectiveSince dexamethasone has immunosuppressive properties, this study attempted to elucidate its effects on the efficacy of immunotherapy plus chemotherapy in patients with non-squamous NSCLC. MethodsThe study retrospectively analyzed the medical records of 254 advanced non-squamous NSCLC patients who received front-line treatment with a PD-1 pathway inhibitor and platinum-based chemotherapy at three academic institutions. The average dosage of prophylactic dexamethasone per chemotherapy cycle was calculated. Patients were divided into three groups based on the dose of dexamethasone: High-d (≥24 mg), Moderate-d (12–24 mg), and Low-d (<12 mg). Spearman's rank correlation was used to assess the correlation between the dosage of dexamethasone and progression-free survival (PFS). Logistic regression was used to assess the correlation between dexamethasone dosage and the occurrence of immune related adverse effects (irAE). Univariate and multivariate Cox proportional hazards regression models were used to analyze the differences in survival among the different dexamethasone dosage groups. ResultThe dosage of prophylactic dexamethasone was not significantly correlated with PFS (Spearman’s rho = -0.103, P = 0.098). Results from the univariate [hazard ratio (HR)Low-d/High-d, 1.00; P = 0.997; HRModerate-d/High-d, 0.85; P = 0.438] and multivariate (HRLow-d/High-d, 0.71; P = 0.174; HRModerate-d/High-d, 0.87; P = 0.512) analyses showed no significant association between dexamethasone and PFS. Dexamethasone did not have significant effect on the objective response rate, disease control rate or overall survival. The toxicity profiles of irAE were similar across all three groups. ConclusionThe results of this study suggest that the use of prophylactic dexamethasone does not have an adverse effect on the clinical outcomes of non-squamous NSCLC patients treated with PD-1 blockade therapy and chemotherapy. Routine use of dexamethasone for preventing CAAEs should be recommended for patients undergoing combined immunotherapy and chemotherapy.

Programmed cell death-1 blockade therapy in melanoma: Resistance mechanisms and combination strategies.

Melanoma is a highly aggressive tumor derived from melanocytes. In recent years, the incidence and mortality of melanoma have gradually increased, seriously threatening human health. Classic treatments like surgery, chemotherapy, and radiotherapy show very limited efficacy. Due to the high immunogenicity of melanoma cells, immune checkpoint inhibitors have received considerable attention as melanoma treatments. One such therapy is blockade of programmed cell death-1 (PD-1), which is one of the most important negative immune regulators and is mainly expressed on activated T cells. Disruption of the interactions between PD-1 and its ligands, programmed death-ligand 1 (PD-L1) or programmed death-ligand 2 (PD-L2) rejuvenates exhausted T cells and enhances antitumor immunity. Although PD-1 blockade therapy is widely used in melanoma, a substantial proportion of patients still show no response or short durations of remission. Recent researches have focused on revealing the underlying mechanisms for resistance to this treatment and improving its efficacy through combination therapy. Here, we will introduce the resistance mechanisms associated with PD-1 blockade therapy in melanoma and review the combination therapies available.

SERS Multiplex Profiling of Melanoma Circulating Tumor Cells for Predicting the Response to Immune Checkpoint Blockade Therapy.

Immune checkpoint blockade (ICB) therapy has achieved remarkable success in many cancers including melanoma. However, ICB therapy benefits only a small proportion of patients and produces severe side effects for some patients. Thus, there is an urgent need to identify patients who are more likely to respond to ICB therapy to improve outcomes and minimize side effects. To predict ICB therapy responses, we design a surface-enhanced Raman scattering (SERS) assay for multiplex profiling of circulating tumor cells (CTCs) under basal and interferon-γ (IFN-γ) stimulation. Through simultaneous ensemble and single-cell measurements of CTCs, the SERS assay can reveal tumor heterogeneity and offer a comprehensive CTC phenotype for decision-making. Anisotropic gold-silver alloy nanoboxes are utilized as SERS plasmonic substrates for improved signal readouts of CTC surface biomarkers. By generating a unique CTC signature with four surface biomarkers, the developed assay enables the differentiation of CTCs from three different patient-derived melanoma cell lines. Significantly, in a cohort of 14 melanoma patients who received programmed cell death-1 blockade therapy, the changes of CTC signature induced by IFN-γ stimulation to CTCs show the potential to predict responders. We expect that the SERS assay can help select patients for receiving ICB therapy in other cancers.

Fibroblast activation protein in the tumor microenvironment predicts outcomes of PD-1 blockade therapy in advanced non-small cell lung cancer

PurposeThe identification of robust predictive biomarkers of the response to programmed cell death-1 (PD-1) blockade remains a critical concern. Here, we investigated on fibroblast activation protein (FAP) as a microenvironment-derived biomarker of clinical outcomes of PD-1 blockade therapy, and the correlation between FAP expression and T cell infiltration in advanced non-small cell lung cancer (NSCLC).MethodsA total of 135 patients with advanced NSCLC who received PD-1 blockade therapy were retrospectively analyzed. The potential associations among FAP expression, CD3 + T cell and CD8 + T cell infiltration, and clinical outcomes of immunotherapy were validated by immunohistochemistry, bioinformatic analyses, and statistical measurements.ResultsFAP was widely expressed in advanced NSCLC tissues. FAP was correlated with decreased density of CD8 + T cells (Spearman’s rho – 0.32, p < 0.001) and immunosuppressive tumor microenvironment (TME) status. No correlations were detected between FAP and PD-L1 expression or with the density of CD3 + T cells. The patients with higher expression of FAP showed worse response rate (16.4% vs. 38.7%, p < 0.001) and worse progression-free survival (HR = 2.56, 95% CI 1.69–3.87, p < 0.001). In addition, FAP contributed to shortened overall survival in subgroups of the patients with squamous cell lung cancer (p = 0.020), PD-1 blockade monotherapy (p = 0.017), and first-line therapy (p = 0.028).ConclusionFAP is a potential predictive biomarker of resistance to PD-1 blockade. Further investigation is warranted to identify a strategy for targeting FAP to alleviate the immunosuppressive TME and broaden the clinical effectiveness of PD-1 blockade therapy.

Tertiary lymphoid structure patterns predicted anti-PD1 therapeutic responses in gastric cancer

Recent studies have highlighted the distinct value of tertiary lymphoid structure (TLS) for immunotherapeutic response prediction. However, it remains unclear whether TLS could play such roles in gastric cancer (GC). In this study, tumor tissue slices from 292 GC patients from Zhongshan Hospital were firstly reviewed to explore the correlation between TLS and clinical characteristics. Subsequently, we curated 38 reported genes that may function as triggers of TLS and performed consensus molecular subtyping in public RNA-seq datasets to determine TLS patterns in GC. Based on the differentially expressed genes acquired from two TLS patterns, we quantified TLS-related genes on the principal component analysis (PCA) algorithm to develop TLS score. A Zhongshan immunotherapy cohort including 13 patients who received programmed cell death 1 (PD1) blockade therapy was established to conduct RNA sequencing analysis and multiplex immunohistochemistry (mIHC) tests using formalin-fixed and paraffin-embedded (FFPE) tissues. The corresponding TLS score and immune cell counts were further compared based on therapeutic response variations. Mature TLS was revealed as an independent prognostic factor in 292 GC patients. Patients with higher TLS score was characterized by prolonged survival time and superior response to immunotherapy. TLS score was correlated with immunotherapy-related characters, such as microsatellite instability (MSI) and tumor mutation burden (TMB). In addition, RNA-seq data analysis in the Zhongshan immunotherapy cohort indicated that a higher TLS score was correlated with a superior response to PD1 blockade therapy. mIHC tests also revealed that PD1+CD8+ T cell counts were significantly increased in the high-TLS score group. This study highlighted that TLS was significantly associated with immune landscape diversity and complexity. Quantitatively evaluating TLS patterns of individual tumor will strengthen our understanding of TME characteristics and promote more effective immunotherapy strategies.

Blocking Wnt/β-catenin Signal Amplifies Anti-PD-1 Therapeutic Efficacy by Inhibiting Tumor Growth, Migration, and Promoting Immune Infiltration in Glioblastomas.

Glioblastoma (GBM), as the immunologically cold tumor, respond poorly to programmed cell death 1 (PD-1) immune checkpoint inhibitors because of insufficient immune infiltration. Herein, through the analysis of The Cancer Genome Atlas data and clinical glioma samples, we found Wnt/β-catenin signal was activated in GBM and inversely related to the degree of immune cell (CD8+) infiltration and programmed cell death ligand 1 (PD-L1) expression. Blockade of Wnt/β-catenin signal could inhibit GBM U118 cells' growth and migration, and upregulate their PD-L1 expression which indicated the possible better response to anti-PD-1 immunotherapy. Besides, in a co-culture system comprising U118 cells and Jurkat cells, Wnt inhibition alleviated Jurkat cell's apoptosis and enhanced its cytotoxic function as evidenced by obviously increased effector cytokine IFNγ secretion and lactate dehydrogenase release. Moreover, the enhanced anti-GBM effect of PD-1 antibody triggered by Wnt inhibition was observed in GL261 homograft mouse model, and the upregulation of immune cell (CD4+/CD8+) infiltration and IFNγ secretion in tumor tissues suggested that Wnt/β-catenin inhibition could inflame cold tumor and then sensitize GBM to PD-1 blockade therapy. Taken together, our study verified the blockade of Wnt/β-catenin signal could augment the efficacy of PD-1 blockade therapy on GBM through directly inhibiting tumor proliferation and migration, as well as facilitating T-cell infiltration and PD-L1 expression in tumor microenvironment.

Complete response to PD-1 blockade following EBV-specific T-cell therapy in metastatic nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is an Epstein–Barr virus (EBV)-associated heterogeneous disease and is characterized by peritumoral immune infiltrate. Adoptive T-cell therapy (ACT) has emerged as a potential therapeutic strategy for NPC. However, the tumor microenvironment remains a major roadblock for the successful implementation of ACT in clinical settings. Expression of checkpoint molecules by malignant cells can inhibit the effector function of adoptively transferred EBV-specific T cells. Here we present a novel case report of a patient with metastatic NPC who was successfully treated with a combination of EBV-specific ACT and programmed cell death-1 blockade therapy. Following combination immunotherapy, the patient showed complete resolution of metastatic disease with no evidence of disease relapse for 22 months. Follow-up immunological analysis revealed dramatic restructuring of the global T-cell repertoire that was coincident with the clinical response. This case report provides an important platform for translating these findings to a larger cohort of NPC patients.

CXCL13 shapes immunoactive tumor microenvironment and enhances the efficacy of PD-1 checkpoint blockade in high-grade serous ovarian cancer

BackgroundMost patients with high-grade serous ovarian cancer (HGSC) lack an effective response to immune checkpoint blockade, highlighting the need for more knowledge about what is required for successful treatment. As...

Clinical features and thyroid dysfunction in adverse events involving the pituitary gland during PD-1 blockade therapy.

Programmed cell death-1 (PD-1) blockade therapy, an immune checkpoint treatment, can induce hypophysitis or hypopituitarism as an immune-related adverse event (pituitary irAE). We aimed to clarify the clinical features of pituitary irAEs during PD-1 blockade therapy. This retrospective study investigated consecutive patients treated with nivolumab, an anti-PD-1 antibody, at Kyoto University Hospital between 1 September 2014 and 31 August 2019. We examined patients' baseline characteristics and analysed the clinical data of those who developed pituitary irAEs. Of the 374 recruited patients, 7 (1.9%) developed pituitary irAEs, and each presented with isolated secondary adrenal insufficiency. In 4 patients, changes in ACTH were delayed relative to those in cortisol: when serum cortisol levels fell below the reference range, plasma ACTH levels were still normal. Pituitary irAEs were accompanied by elevated serum-free T3 (fT3) levels, which resolved with glucocorticoid replacement. Serum TSH levels were not suppressed despite elevated serum fT3 levels and 1 patient even presented with high fT3 level above the reference range (fT3, 7.1pmol/L; free T4 (fT4), 13.9pmol/L; and TSH, 5.1mIU/L). Isolated secondary adrenal insufficiency was a common pituitary irAE during PD-1 blockade therapy. This condition was accompanied by thyroid dysfunction, including elevation of fT3 without TSH suppression.

Tumor cell-intrinsic PD-1 receptor is a tumor suppressor and mediates resistance to PD-1 blockade therapy

The programmed cell death 1 (PD-1) receptor on the surface of immune cells is an immune checkpoint molecule that mediates the immune escape of tumor cells. Consequently, antibodies targeting PD-1 have shown efficacy in enhancing the antitumor activity of T cells in some types of cancers. However, the potential effects of PD-1 on tumor cells remain largely unknown. Here, we show that PD-1 is expressed across a broad range of tumor cells. The silencing of PD-1 or its ligand, PD-1 ligand 1 (PD-L1), promotes cell proliferation and colony formation in vitro and tumor growth in vivo. Conversely, overexpression of PD-1 or PD-L1 inhibits tumor cell proliferation and colony formation. Moreover, blocking antibodies targeting PD-1 or PD-L1 promote tumor growth in cell cultures and xenografts. Mechanistically, the coordination of PD-1 and PD-L1 activates its major downstream signaling pathways including the AKT and ERK1/2 pathways, thus enhancing tumor cell growth. This study demonstrates that PD-1/PD-L1 is a potential tumor suppressor and potentially regulates the response to anti-PD-1/PD-L1 treatments, thus representing a potential biomarker for the optimal cancer immunotherapeutic treatment.

The potential application of PD-1 blockade therapy for early-stage biliary tract cancer.

Biliary tract cancer (BTC) is an aggressive cancer with a poor prognosis partially due to the limited success in developing novel therapies, including molecularly targeted therapies and immunotherapies. Programmed cell death-1 (PD-1) blockade therapy is less effective against BTCs, necessitating further studies to understand the detailed immunological status of the tumor microenvironment (TME) in BTC. Here, we examined the immunological status of the TME in 37 BTCs with early- to late-stage disease, especially focusing on PD-1+CD8+ T cells. PD-1+CD8+ T cells, which are reportedly associated with the clinical response to PD-1 blockade therapy, were frequently observed in early-stage BTC and decreased with disease progression. Imaging mass cytometry for representative PD-1+CD8+TIL-high and -low patients demonstrated that tumor-infiltrating PD-1+CD8+ T cells were localized adjacent to tumor cells, whereas PD-1-CD8+ T cells were detected mainly in the stroma of the TME. In a mouse model, PD-1 expression by tumor-infiltrating CD8+ T cells was higher in smaller tumors and decreased with tumor growth. Consequently, large tumors became resistant to PD-1 blockade, while small tumors containing higher numbers of PD-1+CD8+ T cells were sensitive. We propose the important role of tumor-infiltrating PD-1+CD8+ T cells in anti-tumor immunity and the potential application of PD-1 blockade therapy for early-stage BTC.

CAR-T 19 combined with reduced-dose PD-1 blockade therapy for treatment of refractory follicular lymphoma: A case report.

Anti-CD19 chimeric antigen receptor T cell (CAR-T) therapy has changed the typical outcomes of relapsed/refractory B-cell leukemia and lymphoma. However, treatment effectiveness for patients with relapsed/refractory B-cell non-Hodgkin lymphoma has been less satisfactory compared with patients with B-cell acute lymphoblastic leukemia. The present study described a case of refractory follicular lymphoma. A high expression of programmed cell death 1 (PD-1) was measured on CD3+ T cells (80.90%) in peripheral blood samples obtained from the patient enrolled in this study, indicating that treatment with autologous CAR-T 19 cell therapy may not be successful. Therefore, a therapy regimen consisting of CAR-T 19 cells in combination with a reduced dose of nivolumab (1.5 mg/kg) for PD-1 blockade was used. A low dose of PD-1 blockade therapy was used to reduce the adverse effects associated with the combination of a PD-1 inhibitor and CAR-T 19 cells. This salvage therapy resulted in remission that lasted for >10 months.

Abstract CT120: A randomized, open-label, open-platform, Phase II study evaluating the efficacy and safety of novel spartalizumab (PDR001) combinations in previously treated unresectable or metastatic melanoma (PLATforM)

Abstract Background: Significant advancements, including development of immune checkpoint inhibitors and targeted therapies, have transformed outcomes in patients (pts) with unresectable or metastatic melanoma. However, pts who do not respond or who progress while receiving these regimens have limited options. Spartalizumab (PDR001) is a high-affinity, humanized monoclonal antibody blocking the programmed cell death 1 (PD-1) receptor. This study is evaluating combinations of spartalizumab with novel compounds to restore antitumor T-cell activity in pts with melanoma progressing after prior PD-1 blockade therapy. Methods: This randomized, open-label, 2-part, multicenter, open-platform, Phase II study (NCT03484923; PLATforM) will evaluate the safety and efficacy of spartalizumab combination treatment in pts with unresectable or metastatic melanoma progressing after prior anti-PD-1/L1 therapy and, if the tumor harbors a BRAF V600 mutation, a BRAF inhibitor. The primary endpoint is objective response rate per RECIST v1.1, with duration of response and assessment of paired tumor biopsies for biomarkers of antitumor T-cell activity as part of the secondary endpoints. Part 1, “selection”, will begin with 3 combination arms: (1) spartalizumab + LAG525 (LAG-3 antibody), (2) spartalizumab + capmatinib (c-MET inhibitor), and (3) spartalizumab + canakinumab (IL-1β antagonist). The PLATforM study will use an adaptive design during the selection part that allows for dropping arms for futility, adding new arms, and selecting 1 or multiple arms for further expansion. Bayesian methodology will be used with specific probability criteria for futility and efficacy assessments at each interim analysis. Pts (≈ 60-85) will be stratified by baseline lactate dehydrogenase level and randomized equally to all open arms during the selection part. Part 2, “expansion”, will further investigate the efficacy and safety of treatment combination(s) selected during part 1. The sample size for part 2 will be adaptive and based on predictive power calculations considering the results from part 1. Previously presented at ESMO 2018, FPN 1304TiP, Weber et al. Reused with permission. Citation Format: Caroline Robert, Reinhard Dummer, Ana Arance, Antoni Ribas, Jeffrey Weber, Georgina V. Long, John Haanen, Paul Nathan, Paolo A. Ascierto, Eduard Gasal, Anthony D'Amelio, Severine Bettinger, Aislyn D. Boran, Dirk Schadendorf. A randomized, open-label, open-platform, Phase II study evaluating the efficacy and safety of novel spartalizumab (PDR001) combinations in previously treated unresectable or metastatic melanoma (PLATforM) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT120.

Abstract LB-014: Antibody targeting soluble NKG2D ligand sMIC sensitizes metastatic prostate tumor and other MIC+ tumors to PD1/PD-L1 blockade therapy in pre-clinical models

Abstract Targeting programmed cell death-1 (PD-1) has produced a survival benefit for patients diagnosed with many types of malignancies. However, the clinical survival benefit in metastatic prostate cancer is only marginal to-date. Currently, the understanding of why metastatic prostate cancer is resistant to PD-1 blockade therapy remains to be defined. Among the many factors that negatively impact response to PD-1 blockade treatment, tumor-derived soluble NKG2D ligands have been reported to hinder the clinical response to immune checkpoint blockade in melanoma patients. Metastatic prostate cancer cells release high levels of the circulating soluble NKG2D ligand, soluble MHC I Chain related molecule (sMIC), a molecule that is absent in classical rodent tumor model. Here, we tested the hypothesis that targeting sMIC sensitizes metastatic prostate tumors to PD-1 blockade therapy. Using a well-described double transgenic TRAMP/MIC mouse model that closely resembles the onco-immune dynamics of human metastatic prostate cancer, we demonstrate that an antibody targeting sMIC significantly enhances the response of prostate tumors to PD-1/PD-L1 blockade therapy. Mechanistically, targeting sMIC enriches NK cell and CD8 T cell infiltration into tumors, equips CD8 T cells with enhanced NKG2D and CD28 dual co-stimulation, and increases the expression of PD-L1+ on prostate tumor cells. Combination of the antibody targeting sMIC and a PD-1/PD-L1 blockade cooperatively augments intra-tumoral NK and antigen-specific CD8 T cell anti-tumor immunity. These findings were validated in syngeneic prostate tumor transplant models and other models of other cancer types. Our pre-clinical study provides proof-of-concept and uncovered novel mechanisms of a viable combination immunotherapy for metastatic prostate cancer and other MIC+ cancers. Citation Format: Jennifer D. Wu, Jinyu Zhang, Pablo Larrocha, Payal Dhar. Antibody targeting soluble NKG2D ligand sMIC sensitizes metastatic prostate tumor and other MIC+ tumors to PD1/PD-L1 blockade therapy in pre-clinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-014.

CD4+ T-cell immunity predicts long-lasting antitumor immunity after PD-1 blockade therapy.

2545 Background: Patients treated with programmed cell death 1 (PD-1)-blockade therapy fall into 3 distinct subgroups: non-responders presenting early disease progression, long survivors who achieve durable disease control, and the remaining short-term responders. We reported that the prediction formula comprised of the percentages of CD62L-downregulated (CD62Llow) and CD25+FOXP3+CD4+T cells in the peripheral blood predicted non-responders of non-small cell lung cancer patients (n = 50) scheduled to receive anti-PD-1-antibody (nivolumab) therapy in the 2017 ASCO meeting. In this study, we included 171 patients with NSCLC who were scheduled for nivolumab treatment after obtaining written informed consent. Peripheral blood mononuclear cells (PBMC) were examined before and after Nivolumab therapy up to 2 years to investigate the differences between long survivors and short-term responders. Methods: The patients received Nivolumab at a dose of 3 mg per kilogram of body weight every 2 weeks. Tumor response was assessed with the use of the Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1, at week 8 and every 8 weeks thereafter. PBMCs were analyzed with a 18-color microfluorometer, LSR Fortessa and a masscytometer, CyTOF. Results: The responder-type patient group whose prediction formula values were greater than 192 showed significantly longer PFS ( P&lt; 0.0001) and OS ( P&lt; 0.0001). The long survivors who consisted of tail plateau of PFS exhibited significantly more CD62LlowCD4+T cells than the short-term responders as pre-existing immunity. The remaining responders kept significantly higher percentages of CD62LlowCD4+T cells ( P= 0.0088) and prediction formula values ( P= 0.017) than the patients with acquired resistance. Conclusions: The pre-existing CD4+T cell balance between primed effector and regulatory T cells correlated with anti-PD-1 therapy response. Further, CD62Llowcell-dominant CD4+T cell immunity was required to maintain durable antitumor reactivity induced by anti-PD-1 antibody therapy. These results have important clinical implication, as they support anti-PD-1 therapy provision to all potentially responding patients and pave the way for new treatment strategies for patients with distinct CD4+T cell immune statuses. Clinical trial information: UMIN000020719.

PD-L1 Testing in Non-small Cell Lung Cancer: Past, Present, and Future.

Blockade of the programmed cell death-1 (PD-1) axis has already been established as an effective treatment of non-small cell lung cancer. Immunohistochemistry (IHC) for programmed death-ligand 1 (PD-L1) protein is the only available biomarker that can guide treatment with immune checkpoint inhibitors in non-small cell lung cancer. Because each PD-1/PD-L1 blockade was approved together with a specific PD-L1 IHC assay used in the clinical trials, pathologists have been challenged with performing various assays with a limited sample. To provide a more unified understanding of this, several cross-validation studies between platforms have been performed and showed consistent results. However, the interchangeability of assays may be limited in practice because of the risk of misclassification of patients for the treatment. Furthermore, several issues, including the temporal and spatial heterogeneity of PD-L1 expression in the tumor, and the potential for cytology specimens to be used as an alternative to tissue samples for PD-L1 testing, have still not been resolved. In the future, one of the main aims of immunotherapy research should be to find a novel predictive biomarker for PD-1 blockade therapy and a way to combine it with PD-L1 IHC and other tests.

TLR4 signaling improves PD-1 blockade therapy during chronic viral infection.

CD8 T cells are necessary for the elimination of intracellular pathogens, but during chronic viral infections, CD8 T cells become exhausted and unable to control the persistent infection. Programmed cell death-1 (PD-1) blockade therapies have been shown to improve CD8 T cell responses during chronic viral infections. These therapies have been licensed to treat cancers in humans, but they have not yet been licensed to treat chronic viral infections because limited benefit is seen in pre-clinical animal models of chronic infection. In the present study, we investigated whether TLR4 triggering could improve PD-1 therapy during a chronic viral infection. Using the model of chronic lymphocytic choriomeningitis virus (LCMV) infection in mice, we show that TLR4 triggering with sublethal doses of lipopolysaccharide (LPS) followed by PD-1 blockade results in superior improvement in circulating virus-specific CD8 T cell responses, relative to PD-1 blockade alone. Moreover, we show that the synergy between LPS and PD-1 blockade is dependent on B7 costimulation and mediated by a dendritic cell (DC) intrinsic mechanism. Systemic LPS administration may have safety concerns, motivating us to devise a safer regimen. We show that ex vivo activation of DCs with LPS, followed by adoptive DC transfer, results in a similar potentiation of PD-1 therapy without inducing wasting disease. In summary, our data demonstrate a previously unidentified role for LPS/TLR4 signaling in modulating the host response to PD-1 therapy. These findings may be important for developing novel checkpoint therapies against chronic viral infection.

Efficacy of PD-1 or PD-L1 inhibitors and PD-L1 expression status in cancer: meta-analysis

ObjectiveTo evaluate the relative efficacy of programmed cell death 1 (PD-1) or programmed cell death ligand 1 (PD-L1) inhibitors versus conventional drugs in patients with cancer that were PD-L1 positive...