Programmed Cell Death Ligand 1 Checkpoint Research Articles

Effect of radiotherapy on the residual circulating epithelial tumor cells (CETCs) and their programmed cell death ligand 1 (PD-L1) status in breast cancer patients.

e14034 Background: Preclinical studies have suggested that radiotherapy (RT) followed by immunotherapy could be a promising strategy for synergistic enhancement of treatment efficacy. RT induces immunogenic changes in cancer cells which can lead to adaptive up-regulation of PD-L1 expression. Moreover, radiotherapy reduces not only local recurrence but also improves overall survival by preventing distant metastases, which indicates its influence on the remaining occult tumor, such as circulating tumor cells. For this reason the aim of this study was to determine the PD-L1 status on CETCs before and during RT. Methods: CETCs were determined in 54 primary breast cancer patients in early and locally advanced stages. The number of CETCs and their expression of PDL-L1 were investigated using the maintrac method. The fraction of PD-L1 positive CETCs was assessed prior to (baseline), 3 and 6 weeks after the start of radiotherapy. Results: We found a correlation between the PD-L1 status of CETCs and aggressiveness of cancer disease prior to radiotherapy. Patients with positive lymph node status presented more PD-L1 positive CETCs compared to patients with negative lymph nodes (mean 73% vs. 50%, p < 0.01). Moreover, the HER2 expression of the primary tumor was also positively correlated with PD-L1 expression. Lower numbers of CETCs were detected in patients who had not received chemotherapy or adjuvant chemotherapy before RT than in those who received neoadjuvant chemotherapy (median 20 vs 25 vs 120 CETC/100µl blood, p < 0.001). Surprisingly, the fraction of PD-L1 positive CETCs decreased during radiotherapy only in patients who had received neoadjuvant chemotherapy. Conclusions: Although the number of CETCs and the fraction of PD-L1 positive CETCs were higher in patients who had received neoadjuvant chemotherapy, radiotherapy reduced both measured biomarkers. In the future PD-1/PD-L1 checkpoint inhibitors after radiotherapy might have additional benefit in breast cancer patients.

Predictive biomarkers for PD-1 and PD-L1 immune checkpoint blockade therapy.

The immune system is very important for monitoring and eradicating cancer cells. However, there may be multiple immunosuppressive mechanisms to prevent effective antitumor immunity in the tumor environment, such as the negative immunologic regulators known as checkpoints. Antibodies that block the checkpoints programmed cell death protein 1 (PD-1) pathway have made great success. Nevertheless, the response rates are likely to vary widely. Therefore, several researches are currently underway to determine which biomarkers are able to identify the group of patients who can obtain benefits from PD-1and programmed cell death-ligand 1 (PD-L1) immune checkpoint blockade therapy. This review focuses on potential predictive biomarkers for PD-1/PD-L1 checkpoint blockade immunotherapy in order to provide advice and guidance for clinical treatment.

Programmed cell death-1/programmed cell death ligand-1 checkpoint inhibitors: differences in mechanism of action.

Programmed cell death-1 (PD-1)/programmed death-ligand 1 (PD-L1) checkpoint inhibitors are widely used in many types of solid tumors, and are often considered to be in the same immunotherapy subclass. This review explores whether specific agents in these two categories exhibit differences in their mechanism of action, pharmacokinetics and pharmacodynamics, and clinical efficacy and safety. Due to the complicated functional pathways in the immune checkpoint system, the epitopes, interfaces and signal pathways between PD-1: PD-L1/PD-L2, PD-L1/CD28/CTLA-4: B7-1 axes often overlap and affect each other. Therefore, the mechanisms of action of PD-1 and PD-L1 inhibitors reflect the corresponding cross connectivity and their unique characteristics. Only head-to-head comparative studies can provide definitive information regarding clinical efficacy and safety differences between specific PD-1/PD-L1 inhibitors.

Expression of programmed cell death ligand 1 and immune checkpoint markers in residual tumors after neoadjuvant chemotherapy for advanced high-grade serous ovarian cancer

ObjectiveTo investigate the prognostic value of the expressions of programmed cell death ligand 1 (PD-L1) and immune checkpoint markers in residual tumors after neoadjuvant chemotherapy (NAC) for advanced high-grade serous ovarian cancer (HGSOC). MethodsWe collected pre- and post-NAC tumor samples from patients with advanced HGSOC between 2006 and 2017. Post-NAC tumor tissue samples were available for immunostaining from 131 patients. The expressions of PD-L1 and immune checkpoint markers were assessed by immunohistochemical staining and the status of tumor-infiltrating lymphocytes (TILs) was also evaluated. We examined whether there are significant associations between protein expression status and patient outcomes and whether significant changes in protein expression levels occurred in response to NAC. ResultsPD-L1 expression in the tumor cells was evaluated in 113 patients, 12 (10.6%) of whom had high PD-L1 expression (≥25%) in post-NAC tissues. However, these high levels were not associated with progression-free survival (PFS; P = 0.348) or overall survival (OS; P = 0.699). Similarly, high stromal TILs [≥50%; n = 16 (15.0%)] among the 107 patients evaluated did not show any significant impact on PFS (P = 0.250) or OS (P = 0.800). Moreover, an abundance of TILs (intraepithelial, CD8+, and Foxp3+) and the expression of immune checkpoint markers (PD-1, ICOS, and LAG-3) in residual tumors did not confer any significant survival benefit. The impact of NAC on PD-L1 expression and stromal TILs varied considerably among individual patients. ConclusionAlthough the expression of PD-L1 and immune checkpoint markers in residual tumors after NAC had no prognostic impact on survival in patients with HGSOC, post-NAC evaluation of these proteins in chemoresistant tumors may help select patients for immunotherapy trials.

\u2018DURVIT\u2019: a phase-I trial of single low-dose durvalumab (Medi4736) IntraTumourally injected in cervical cancer: safety, toxicity and effect on the primary tumour- and lymph node microenvironment

BackgroundTreatment with programmed cell death receptor (PD-1) and programmed cell death ligand 1 (PD-L1) inhibitors is a promising strategy to lift tumour-induced immune response suppression. However, the current systemic treatment often causes autoimmune side effects. In more than 50% of squamous cell cervical cancer, PD-L1 expression is detected. Moreover, we observed high and interrelated rates of PD-L1 positive macrophages and regulatory T cells in metastatic lymph nodes of cervical cancer patients. As cervical cancer in general initially metastasizes to regional lymph nodes, local administration of durvalumab (a PD-L1 checkpoint inhibitor) at an early stage will deliver these antibodies exactly where they are needed, facilitating immune protection. This may result in a clinical benefit while reducing undesirable side effects.MethodsDURVIT is a non-randomized, single-arm, open-label, phase I study. Three escalating dose levels of intratumourally (i.t.) injected durvalumab will be tested, i.e. 5, 10 and 20 mg (three patients per dose level, with an additional three at the highest tolerated dose). The primary endpoint of this phase-I study is safety. Immune monitoring will consist of flow cytometric, immunohistochemical and functional T cell reactivity testing. The first patient has been included in this trial in November 2017.DiscussionEvidence of safety and biological efficacy of this locally administered checkpoint blockade may expand adjuvant therapy options for cervical cancer patients. Early metastatic spread of cervical cancer cells may thus be controlled in the draining lymph node basin, and beyond, and hopefully delay or even prevent the onset of disease recurrence.Trial registrationNTR6119, 1-nov-2016.

Abstract 4551: Thyroid hormone induces PD-L1 expression in oral cancer cells

Abstract Oral cancer is a fatal disease, which accounts for the fourth highest incidence of malignancy in males and the seventh highest in the general population of Taiwan. Oral cancer is increasing in Taiwan. About 95% of oral cancer in Taiwan is oral squamous cell carcinoma (OSCC). With the development of cancer molecular biology and immunology, targeted therapy for immune checkpoints of programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1) has shown enormous development prospects for treatment of head and neck cancer. The PD-1/PD-L1 checkpoint is a critical regulator of activated T cell-cancer cell interactions which defend tumor cells against immune surveillance. Thyroid hormone induces PD-L1 expression in human oral cancer cells. Human oral cancer OEC-M1 and SCC-25 cells were treated with different concentrations of T4 (10-8 to 10-6M) for 24 h and cells were harvested and total RNA was extracted. qPCR of PD-L1 revealed that PD-L1 mRNA was significantly induced by thyroid hormone on a concentration-dependent basis. Parallel studies were conducted to study the effect of thyroid hormone on PD-L1 protein accumulation. Cancer cells were treated with different concentrations of T4 for 24 h. Total proteins were extracted and western blot analysis of PD-L1 was conducted. Thyroid hormone-activated ERK1/2 and STAT3 were companied with PD-L1 expression. Inhibition of ERK1/2 and consequently STAT3 activation also blocked PD-L1 induced by thyroid hormone. Knockdown of PD-L1 expression by siRNA also inhibits thyroid hormone-induced proliferation of oral cancer cells which indicated that PD-L1 expression is involved in thyroid hormone-induced cancer growth via an ERK1/2-STAT3 signal transduction pathway in oral cancer cells. Citation Format: Yu-Tang Chin, Kwan-Wei Su, Yee-Tang Lim, Ya-Jung Shih, Yi-Ru Chen, Sheng-Yang Lee, Paul J. Davis, Hung-Yun Lin, Earl Fu. Thyroid hormone induces PD-L1 expression in oral cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4551.

Assessment of programmed cell death ligand-1 expression with multiple immunohistochemistry antibody clones in non-small cell lung cancer.

Programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1) have been identified as novel targets for immunotherapy, with PD-L1 as a potential predictive biomarker. However, a specific antibody for PD-L1 expression is an immediate requirement. Meanwhile, the clinicopathological identification of patients with positive PD-L1 remains unclear. The present study adopted three anti-PD-L1 IHC antibodies, SP142, SP263, and UMAB228 to test PD-L1 expression in 84 non-small cell lung cancer (NSCLC) specimens. The concordance among antibodies was examined by analytical comparison, and the association between PD-L1 expression and clinicopathological factors was assessed. The samples from 41 (48.8%), 51 (60.7%), and 50 (59.5%) patients were detected as PD-L1 positive evaluated by antibody SP142, SP263, and UMAB228, respectively. The kappa coefficient was 0.53, 0.58, and 0.46 for SP263 vs. SP142, SP263 vs. UMAB228, and SP142 vs. UMAB228, respectively. On the other hand, the univariate analysis of consensus cases indicated that the PD-L1 expression was significantly correlated with tobacco use (χ2=4.25, P=0.04). The analytical comparison showed moderate concordance between SP142, SP263 and UMAB228, whereas SP263 exhibited higher overall positive rate. Moreover, PD-L1 positive rate was significantly higher in patients with smoking history, which might help in identifying patients who would benefit from PD-1/PD-L1 checkpoint inhibitors.

Companion and Complementary Diagnostics-Focus on PD-L1 Expression Assays for PD-1/PD-L1 Checkpoint Inhibitors in Non-Small Cell Lung Cancer.

Over the last couple of decades, molecular diagnostics have played an increasing role in drug development. Especially within oncology, more and more drugs are being developed together with a predictive biomarker assay using the drug-diagnostic codevelopment model. Not only do these assays support the development process but also the use of the drugs after regulatory approval as an important treatment decision tool. When these predictive biomarker assays are linked to a specific drug, they are called companion diagnostics. Furthermore, these assays are also considered an important element in the realization of precision medicine. Today, 21 different drugs have obtained US FDA approval together with a companion diagnostic assay, and the requirement for testing is part of their regulatory labeling. More than half of these drugs are for treatment of non-small cell lung cancer (NSCLC). With the approval of the different programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) immune checkpoint inhibitors, for the treatment of advanced stage NSCLC, a new class of predictive biomarker assays-complementary diagnostics-has emerged. Until now, 3 immune checkpoint inhibitors have obtained regulatory approval for treatment of NSCLC, and they all have a biomarker assay linked to their use. However, only for pembrolizumab, the PD-L1 immunohistochemical (IHC) 22C3 pharmDx assay has status as a companion diagnostic. For nivolumab and atezolizumab, the assays PD-L1 IHC 22C3 pharmDx and Ventana PD-L1 (SP142) have status as complementary diagnostics, which means that there are no requirements for testing included in the labeling for these drugs. Here, the authors discuss the clinical performance of the different IHC PD-L1 expression assays including the selection of the clinical cutoff values.

PD-L1 checkpoint inhibition and anti-CTLA-4 whole tumor cell vaccination counter adaptive immune resistance: A mouse neuroblastoma model that mimics human disease.

BackgroundAdaptive immune resistance induces an immunosuppressive tumor environment that enables immune evasion. This phenomenon results in tumor escape with progression and metastasis. Programmed cell death-ligand 1 (PD-L1) expressed on tumors is thought to inhibit tumor-infiltrating lymphocytes (TILs) through programmed cell death 1 (PD1), enabling adaptive immune resistance. This study investigates the role of PD-L1 in both mouse and human neuroblastoma immunity. The consequence of PD-L1 inhibition is characterized in the context of an established whole tumor cell vaccine.Methods and findingsA mouse model of neuroblastoma was investigated using an Id2 knockdown whole cell vaccine in combination with checkpoint inhibition. We show that immunogenic mouse neuroblastoma acquires adaptive immune resistance by up-regulating PD-L1 expression, whereas PD-L1 is of lesser consequence in nonimmunogenic neuroblastoma tumors. Combining PD-L1 checkpoint inhibition with whole tumor cell/anti-CTLA-4 vaccination enhanced tumor cell killing, cured mice with established tumors, and induced long-term immune memory (6 months). From an evaluation of patient neuroblastoma tumors, we found that the inflammatory environment of the mouse neuroblastoma mimicked human disease in which PD-L1 expression was associated directly with TILs and lower-risk tumors. High-risk patient tumors were lacking both TILs and PD-L1 expression. Although a correlation in immunity seems to exist between the mouse model and human findings, the mouse tumor model is induced and not spontaneously occurring, and furthermore, the number of both mouse and human correlates is limited.ConclusionsThis study demonstrates the role PD-L1 plays in neuroblastoma’s resistance to immunity and defines the nonredundant effect of combination checkpoint inhibition with vaccine therapy in a mouse model. High-risk, nonimmunogenic human tumors display both diminished PD-L1 expression and adaptive immune resistance. Paradoxically, high-risk tumors may be more responsive to effective vaccine therapy because of their apparent lack of adaptive immune resistance.

PD-L1 immunohistochemistry in clinical diagnostics of lung cancer: inter-pathologist variability is higher than assay variability

Assessment of programmed cell death ligand 1 (PD-L1) immunohistochemical staining is used for decision on treatment with programmed cell death 1 and PD-L1 checkpoint inhibitors in lung adenocarcinomas and squamous cell carcinomas. This study aimed to compare the staining properties of tumor cells between the antibody clones 28-8, 22C3, SP142, and SP263 and investigate interrater variation between pathologists to see if these stainings can be safely evaluated in the clinical setting. Using consecutive sections from a tissue microarray with tumor tissue from 55 resected lung cancer cases, staining with five PD-L1 assays (28-8 from two different vendors, 22C3, SP142, and SP263) was performed. Seven pathologists individually evaluated the percentage of positive tumor cells, scoring each sample applying cutoff levels used in clinical studies: <1% positive tumor cells (score 0), 1–4% (score 1), 5–9% (score 2), 10–24% (score 3), 25–49% (score 4), and >50% positive tumor cells (score 5). Pairwise analysis of antibody clones showed weighted kappa values in the range of 0.45–0.91 with the highest values for comparisons with 22C3 and 28-8 and the lowest involving SP142. Excluding SP142 resulted in kappa 0.75–0.91. Weighted kappa for interobserver variation between pathologists was 0.71–0.96. Up to 20% of the cases were differently classified as positive or negative by any pathologist compared with consensus score using ≥1% positive tumor cells as cutoff. A significantly better agreement between pathologists was seen using ≥50% as cutoff (0–5% of cases). In conclusion, the concordance between the PD-L1 antibodies 22C3, 28-8 and SP263 is relatively good when evaluating lung cancers and suggests that any one of these assays may be sufficient as basis for decision on treatment with nivolumab, pembrolizumab, and durvalumab. The scoring of the pathologist presents an intrinsic source of error that should be considered especially at low PD-L1 scores.

Abstract A096: Myeloid cells are required for pancreatic carcinogenesis and PD-1/PD-L1 checkpoint activation

Abstract Myeloid cells, including both macrophages and immature myeloid cells/myeloid derived suppressor cells (MDSCs), accumulate during the progression of pancreatic cancer. The goal of this study was to determine the effect of myeloid cell depletion on the onset and progression of pancreatic cancer, and to understand the relationship between myeloid cells and T cell-mediated immunity within the pancreatic cancer microenvironment. Primary mouse pancreatic cancer cells were transplanted into CD11b-DTR mice. Alternatively, the iKras* mouse model of pancreatic cancer was crossed into CD11b-DTR mice. CD11b+ cells were depleted by Diphtheria Toxin treatment during tumor initiation or in established tumors. Depletion of myeloid cells prevented KrasG12D driven pancreatic cancer initiation. Myeloid cells are required for sustained MAPK signaling in pancreatic epithelial cells during the onset of carcinogenesis, notwithstanding the expression of oncogenic Kras. In pre-established tumors, myeloid cell depletion arrested tumor growth and in some cases, induced tumor regressions that were dependent on CD8+ T cells. We found that myeloid cells inhibited CD8+ T cell anti-tumor activity by inducing the expression of Programmed cell death-ligand 1 (PD-L1) in tumor cells in an EGFR/MAPK dependent manner. Treatment with MEK inhibitors lowers the intratumoral expression of PD-L1 and renders the tumor susceptible to PD-1 blockade. Our results show that myeloid cells support immune evasion in pancreatic cancer through EGFR/MAPK dependent regulation of PD-L1 expression on tumor cells. Derailing this cross-talk between myeloid cells and tumor cells is sufficient to restore anti-tumor immunity mediated by CD8+ T cells, a finding with implications for the design of immune therapies for pancreatic cancer. Note: This abstract was not presented at the conference. Citation Format: Yaqing Zhang, Ashley Velez-Delgado, Esha Mathew, Dongjun Li, Flor M. Mendez, Kevin Flannagan, Andrew D. Rhim, Diane M. Simeone, Gregory L. Beatty, Marina Pasca di Magliano. Myeloid cells are required for pancreatic carcinogenesis and PD-1/PD-L1 checkpoint activation [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A096.

Myeloid cells are required for PD-1/PD-L1 checkpoint activation and the establishment of an immunosuppressive environment in pancreatic cancer

BackgroundPancreatic cancer is characterised by the accumulation of a fibro-inflammatory stroma. Within this stromal reaction, myeloid cells are a predominant population. Distinct myeloid subsets have been correlated with tumour promotion...