Programmed Death Protein-1 Inhibitor Research Articles

Prognostic analysis of related factors of adverse reactions to immunotherapy in advanced gastric cancer and establishment of a nomogram model.

Immunotherapy for advanced gastric cancer has attracted widespread attention in recent years. However, the adverse reactions of immunotherapy and its relationship with patient prognosis still need further study. In order to determine the association between adverse reaction factors and prognosis, the aim of this study was to conduct a systematic prognostic analysis. By comprehensively evaluating the clinical data of patients with advanced gastric cancer treated by immunotherapy, a nomogram model will be established to predict the survival status of patients more accurately. To explore the characteristics and predictors of immune-related adverse reactions (irAEs) in advanced gastric cancer patients receiving immunotherapy with programmed death protein-1 (PD-1) inhibitors and to analyze the correlation between irAEs and patient prognosis. A total of 140 patients with advanced gastric cancer who were treated with PD-1 inhibitors in our hospital from June 2021 to October 2023 were selected. Patients were divided into the irAEs group and the non-irAEs group according to whether or not irAEs occurred. Clinical features, manifestations, and prognosis of irAEs in the two groups were collected and analyzed. A multivariate logistic regression model was used to analyze the related factors affecting the occurrence of irAEs, and the prediction model of irAEs was established. The receiver operating characteristic (ROC) curve was used to evaluate the ability of different indicators to predict irAEs. A Kaplan-Meier survival curve was used to analyze the correlation between irAEs and prognosis. The Cox proportional risk model was used to analyze the related factors affecting the prognosis of patients. A total of 132 patients were followed up, of whom 63 (47.7%) developed irAEs. We looked at the two groups' clinical features and found that the two groups were statistically different in age ≥ 65 years, Ki-67 index, white blood cell count, neutrophil count, and regulatory T cell (Treg) count (all P < 0.05). Multivariate logistic regression analysis showed that Treg count was a protective factor affecting irAEs occurrence (P = 0.030). The ROC curve indicated that Treg + Ki-67 + age (≥ 65 years) combined could predict irAEs well (area under the curve = 0.753, 95% confidence interval: 0.623-0.848, P = 0.001). Results of the Kaplan-Meier survival curve showed that progression-free survival (PFS) was longer in the irAEs group than in the non-irAEs group (P = 0.001). Cox proportional hazard regression analysis suggested that the occurrence of irAEs was an independent factor for PFS (P = 0.006). The number of Treg cells is a separate factor that affects irAEs in advanced gastric cancer patients receiving PD-1 inhibitor immunotherapy. irAEs can affect the patients' PFS and result in longer PFS. Treg + Ki-67 + age (≥ 65 years old) combined can better predict the occurrence of adverse reactions.

Comparison of Effectiveness of Programmed Death Protein 1 and Programmed Death Ligand 1 Inhibitors in Extensive-Stage Small-Cell Lung Cancer: A Meta-Analysis of Randomized Controlled Trials and Observational Studies.

This meta-analysis aimed to compare the efficacy of programmed death protein 1 (PD-1) inhibitors and programmed death ligand 1 (PD-L1) inhibitors in patients with extensive-stage small-cell lung cancer. The present meta-analysis was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Relevant studies were identified through searches of databases including PubMed, Embase, and the Cochrane Library, as well as prominent oncology conferences. The search was conducted from the inception of the databases up to January 31, 2024. A total of 10 studies were included in this meta-analysis. Among these studies, six were randomized trials, while four were observational studies. The pooled meta-analysis showed that PD-1 and PD-L1 inhibitors are more effective in improving overall survival and progression-free survival compared to chemotherapy alone. However, when comparing PD-1 and PD-L1 inhibitors, there was no significant difference between the two groups regarding overall survival and progression-free survival. It is important to note that there is no head-to-head trial comparing these two interventions in patients with extensive-stage small-cell lung cancer. Therefore, future prospective trials are needed to define optimal therapeutic approaches in this patient population.

PD-L1-positive circulating endothelial progenitor cells associated with immune response to PD-1 blockade in patients with head and neck squamous cell carcinoma.

A number of the inhibitors against programmed death protein 1 (PD-1) have been approved to treat recurrent or metastatic squamous cell carcinoma of head and neck (HNSCC). The interaction between PD-1 and its ligand (PD-L1) serves as an immune checkpoint that governs cytotoxic immune effectors against tumors. Numerous clinical trials of PD-1/PD-L1 inhibitors have so far been discordant about having sufficient PD-L1 expression in the tumor as a prerequisite for a successful anti-PD-1 treatment. On the other hand, vascular endothelial cells modulate immune activities through PD-L1 expression, and thus it is possible that the expressions of circulating endothelial cells (CECs) and circulating endothelial progenitor cells (CPCs) could affect antitumor immunity as well as neoangiogenesis. Here we investigated the potential involvement of PD-L1+ CECs and PD-L1+ CPCs in PD-1 blockade treatments for HNSCC patients. We measured CD8+ T cells, CECs, and CPCs in the peripheral blood of the HNSCC patients treated by anti-PD-1 therapies. We found that their PD-L1+ CPC expression before anti-PD1 therapies was strongly correlated with treatment responses and overall survival. Moreover, if the first infusion of PD-1 inhibitors reduced ≥ 50% PD-L1+ CPCs, a significantly better outcome could be predicted. In these patients as well as in an animal model of oral cancer, Pd-l1+ CPC expression was associated with limited CD8+ T-cell infiltration into the tumors, and anti-PD-1 treatments also targeted Pd-l1+ CPCs and increased CD8+ T-cell infiltration. Our results highlight PD-L1+ CPC as a potential regulator in the anti-PD-1 treatments for HNSCC.

Comparison of efficacy and safety between PD-1 inhibitors and PD-L1 inhibitors plus platinum-etoposide as first-line treatment for extensive-stage small-cell lung cancer: a multicenter, real-world analysis

BackgroundImmunotherapy in combination with platinum-etoposide (EP) chemotherapy has been approved as a first-line treatment for extensive-stage small cell lung cancer (ES-SCLC). However, real-world (RW) data regarding the use of immune checkpoint inhibitors (ICIs) in ES-SCLC are lacking. We aimed to assess the differences between programmed death protein 1 (PD-1) inhibitors and programmed death ligand 1 (PD-L1) inhibitors, both in conjunction with EP chemotherapy, as first-line treatment for ES SCLC.MethodsWe conducted a real-world, multicenter, retrospective cohort, controlled study to compare the prognosis, efficacy, and safety of PD-1 and PD-L1 inhibitors in ES-SCLC patients when used along with chemotherapy. Each patient received up to six cycles of etoposide, carboplatin, or cisplatin combined with ICI drugs, including PD-1 and PD-L1 inhibitors. The primary endpoints were investigator-assessed progression-free survival (PFS) and overall survival (OS). The secondary endpoints were the investigator-assessed objective response rate (ORR) and disease control rate (DCR) according to the Response Evaluation Criteria in Solid Tumors (RECIST, version 1.1).ResultsBetween January 2017 and December 2021, 194 patients with ES-SCLC from three clinical centers in a PLA general hospital were included in our study, including 93 patients in the PD-1 group and 101 patients in the PD-L1 group. At the time of data cutoff, progression-free survival in the PD-1 group (median PFS, 6.8 months; 95% CI, 5.3–8.1) was similar to that in the PD-L1 group (median PFS, 6.4 months; 95% CI, 5.5–7.5); the stratified hazard ratio for PFS was 1.12 (95% CI, 0.83–1.53; P = 0.452). The median OS was similar in the PD-1 and PD-L1 groups (15.8 m vs. 17.7 m, P = 0.566); the hazard ratio was 0.90 (95% CI, 0.62–1.30, P = 0.566). The two groups had comparable investigator-assessed confirmed objective response rates (ORR) (76.3% vs. 76.2%). Adverse effect (AE)-related discontinuation occurred in 4 (4.3%) patients in the PD-1 group and 2 (2.0%) patients in the PD-L1 group. Deaths due to AEs of any cause occurred in 2 (2.2%) patients in the PD-1 inhibitor group and 1 (1.0%) patient in the PD-L1 inhibitor group.ConclusionsOur research revealed that there were no significant differences in efficacy or prognosis between PD-1 inhibitor + EP chemotherapy and PD-L1 inhibitor + EP chemotherapy. The two groups seemed to have comparable safety profiles, but the number of discontinuation or death events was too small to draw a firm conclusion.

Investigate the role of neutrophil extracellular traps in immune checkpoint inhibitor-associated myocarditis with programmed death protein-1 inhibitors involvement

Objective: To investigate the role of neutrophil extracellular traps (NETs) in immune checkpoint inhibitor-associated myocarditis (ICIAM) with programmed death protein-1 (PD-1) inhibitors involvement, and to explore the therapeutic potential of targeting NETs in the treatment of ICIAM. Methods: Thirty 6-week-old male BALB/c mice were randomly divided into control group (n=10), myocarditis group (n=10), and treatment group (n=10). Apart from the control group, each mouse was subcutaneously injected with 100 μl of complete Freund's adjuvant containing 250 μg of mouse cardiac troponin I peptide on the 1st and 7th day. Starting on the 8th day, PD-1 inhibitor (15 μg/per mouse) was intraperitoneally injected every other day for a total of 5 times. Since 1 day before the beginning of PD-1+TnI injection, the treatment group was injected with PF-1355 (50 mg·kg-1·d-1) for 16 consecutive days. The mice's general state was observed during the whole process. Real-time fluorescence quantitative PCR (RTFQ-PCR) was carried out to evaluate the transcriptional regulation of neutrophil related chemokines, NETs, pyronecrosis related factors and proinflammatory cytokines. Immunohistochemistry, immunofluorescence and western blot were applied to determine the changes of pyrosis related molecules. Echocardiography showed the differences of main cardiac indexes while cardiac pathology compared the degree of inflammatory infiltration in 3 gruops. Results: The immunofluorescence intensity of myocardial NETs in the myocarditis group was significantly increased compared to the control group mice (2.49±0.08 and 0.99±0.26, P<0.001). The protein expression levels of pyroptosis-related NLRP3, cleaved-Caspase 1, Caspase 1, cleaved-GSDMD, GSDMD, IL-1β and IL-18 in myocardial tissue of the model group were higher than those of the control group (all P<0.05). After treatment with PF-1355, compared to the myocarditis group, the left ventricular ejection fraction (LVEF) (73.58%±5.31% and 58.12%±3.19%, P<0.001) and left ventricular fraction shortening (LVFS) (39.78%±4.31% and 33.89%±2.19%, P<0.001) increased. H-E staining showed a reduction in inflammatory infiltration area in the treatment group compared to the myocarditis group (30.12%±3.57% and 14.92%±2.46%, P<0.001). The immunofluorescence intensity of NETs decreased in the treatment group compared to the myocarditis group (2.52±0.04 and 1.03±0.05, P<0.001). The levels of NLRP3 and other pyroptosis-related molecules were downregulated in the treatment group compared to the myocarditis group (all P<0.05). Conclusions: NETs lead to myocardial cell pyroptosis by activating the NLRP3 inflammasome in PD-1 inhibitor-associated myocarditis. The specific MPO inhibitor PF-1355 shows a therapeutic potential by regulating the formation of NETs, decreasing NLRP3 level and relieving myocardial pyroptosis, thus reducing myocardial damage.

Immune-related adverse events induced by programmed death protein-1 inhibitors from the perspective of lymphoma immunotherapy.

Lymphoma, which is highly malignant, stems from lymph nodes and lymphoid tissue. Lymphoma cells express programmed death-ligand 1/2 (PD-L1/PD-L2), which binds with programmed cell death 1 protein (PD-1) to establish inhibitory signaling that impedes the normal function of T cells and allows tumor cells to escape immune system surveillance. Recently, immune checkpoint inhibitor immunotherapies such as PD-1 inhibitors (nivolumab and pembrolizumab) have been introduced into the lymphoma treatment algorithm and have shown remarkable clinical efficacy and greatly improve prognosis in lymphoma patients. Accordingly, the number of lymphoma patients who are seeking treatment with PD-1 inhibitors is growing annually, which results in an increasing number of patients developing immune-related adverse events (irAEs). The occurrence of irAEs inevitably affects the benefits provided by immunotherapy, particularly when PD-1 inhibitors are applied. However, the mechanisms and characteristics of irAEs induced by PD-1 inhibitors in lymphoma need further investigation. This review article summarizes the latest research advances in irAEs during treatment of lymphoma with PD-1 inhibitors. A comprehensive understanding of irAEs incurred in immunotherapy can help to achieve better efficacy with PD-1 inhibitors in lymphoma.

994P Efficacy and safety of capmatinib plus spartalizumab in treatment-naïve patients with advanced NSCLC harboring MET exon 14 skipping mutation

Capmatinib (cap) is a selective MET inhibitor approved for patients (pts) with advanced NSCLC (aNSCLC) harboring MET exon 14 skipping mutation (METex14) showing ORR [95% CI] of 66.7% [53.3, 78.3] in treatment (tx)-naïve pts. Spartalizumab (sparta) is a monoclonal antibody targeting programmed death protein-1 (PD-1). Cap enhances T cell mediated antitumor response in mice treated with PD-1 inhibitors. Combining cap with sparta may be beneficial in aNSCLC pts with METex14. This phase II study consisted of 2 parts: open-label, single-arm run-in part, where pts received cap 400 mg orally BID + sparta 400 mg i.v Q4W followed by randomized, double-blind, placebo-controlled part to evaluate the efficacy and safety of cap+sparta vs cap+placebo. Tx-naïve aNSCLC pts with METex14 and without ALK or EGFR alterations were included. The primary endpoint was investigator-assessed ORR as per RECIST v1.1. Herein, we report data from the run-in part. At data cut-off (DCO) of Feb 01, 2022, 31 pts were included in the run-in part; median age: 73 (range: 52-89) years; females (51.6%) and ECOG PS of 0/1 in 38.7%/61.3% of pts. The ORR [95% CI] was 38.7% [21.8, 57.8] and DCR [95% CI] was 77.4% [58.9, 90.4]. Median DOR has not been reached. Median PFS [95% CI] is 13.3 months [9.3, NA] but data remains to mature further. The preliminary PK results of both drugs showed consistency with prior monotherapy studies. Most common Tx-related AEs (any grades [GR], ≥30%) were peripheral edema (71%), elevated serum creatinine (45.2%), elevated ALT and AST (35.5% each). No Tx-related GR 3/4 pneumonitis and no fatal toxicity has been reported. Higher rates of tx-related AEs leading to dose reduction/interruption (80.6%) and/or discontinuation (35.5%) were seen with cap+sparta regimen vs other cap monotherapy studies, suggesting poor tolerability to the combination. Thus, study enrollment was halted, and all ongoing pts were discontinued from sparta. At DCO, 15 pts remain on cap monotherapy. The addition of sparta to cap treatment was not well tolerated and resulted in modest antitumor activity when compared with data from other cap monotherapy studies in tx-naïve aNSCLC pts with METex14.

Dynamics of PD-1 expression are associated with treatment efficacy and prognosis in patients with intermediate/high-risk myelodysplastic syndromes under hypomethylating treatment

Hypomethylating agents (HMAs) are widely used in patients with higher-risk MDS not eligible for stem cell transplantation. However, the general response rate by HMAs is lesser than 50% in MDS patients, while the relapse rate is high. Emerging evidence indicates that demethylating effects committed by HMAs may facilitate the up-regulation of a range of immune checkpoints or cancer suppressor genes in patients with MDS, among which the programmed death protein 1 (PD-1) and its ligands are demonstrated to be prominent and may contribute to treatment failure and early relapse. Although results from preliminary studies with a limited number of enrolled patients indicate that combined administration of PD-1 inhibitor may yield extra therapeutic benefit in some MDS patients, identifications of this subgroup of patients and optimal timing for the anti-PD-1 intervention remain significant challenges. Dynamics of immune checkpoints and associated predictive values during HMA-treatment cycles remained poorly investigated. In this present study, expression levels of immune checkpoints PD-1 and its ligands PD-L1 and PD-L2 were retrospectively analyzed by quantitative PCR (Q-PCR) in a total of 135 myelodysplastic syndromes (MDS) cohort with higher-risk stratification. The prognostic value of dynamics of these immune checkpoints during HMA cycles was validated in two independent prospective cohorts in our center (NCT01599325 and NCT01751867). Our data revealed that PD-1 expression was significantly higher than that in younger MDS patients (age ≤ 60) and MDS with lower IPSS risk stratification (intermediate risk-1). A significantly up-regulated expression of PD-1 was seen during the first four HMA treatment cycles in MDS patients, while similar observation was not seen concerning the expression of PD-L1 or PD-L2. By utilizing binary logistic regression and receiver operating characteristic (ROC) models, we further identified that higher or equal to 75.9 PD-1 expressions after 2 cycles of HMA treatment is an independent negative prognostic factor in predicting acute myeloid leukemia (AML) transformation and survival. Collectively, our data provide rationales for monitoring the expression of PD-1 during HMA treatment cycles, a higher than 75.9 PD-1 expression may identify patients who will potentially benefit from the combined therapy of HMA and PD-1 inhibitors.

Efficacy and safety of capmatinib plus pembrolizumab in treatment (tx)-naïve patients with advanced non–small cell lung cancer (NSCLC) with high tumor PD-L1 expression: Results of a randomized, open-label, multicenter, phase 2 study.

9118 Background: Capmatinib is a selective MET inhibitor approved for patients (pts) with metastatic NSCLC harboring MET exon 14 skipping mutation. Pembrolizumab (pembro) is a programmed death protein-1 (PD-1) inhibitor approved as monotherapy for pts with advanced NSCLC expressing PD-ligand 1 (PD-L1). Preclinical studies have shown that capmatinib enhances T cell mediated antitumor response in mice treated with PD-1 inhibitors. Combining capmatinib with pembro may be beneficial in pts with advanced NSCLC expressing high tumor PD-L1. Methods: Herein we evaluated the efficacy and safety of capmatinib plus pembro (combo) versus pembro alone in tx-naïve pts with advanced MET-unselected NSCLC expressing PD-L1 with tumor proportion score (TPS) ≥50%, and no ALK or EGFR tumor aberrations. Pts received pembro 200 mg IV q3w in the pembro alone arm or with capmatinib 400 mg orally BID in the combo arm. The primary endpoint was investigator-assessed progression-free survival (PFS) using RECIST v1.1. Secondary endpoints included overall response rate (ORR), disease control rate (DCR), pharmacokinetics and safety. Results: As of the data cut off (DCO) of 28 Feb 2021, 76 pts were randomized 2:1 to the combo arm (n = 51) or pembro alone arm (n = 25). Baseline demographics and disease status were mostly comparable across study arms. At this interim analysis, PFS data were not mature. Median PFS (95% CI) was 6.3 (3.2, not evaluable [NE]) months in the combo arm and 4.3 (2.3, NE) months in the pembro alone arm. The ORR (95% CI) was 15.7% (7.0%, 28.6%) and 28.0% (12.1%, 49.4%) in the combo and pembro alone arms, respectively. The DCR (95% CI) was comparable across study arms; combo: 56.9% (42.2%, 70.7%) and pembro alone: 56.0% (34.9%, 75.6%). In the combo arm, capmatinib exposure (Cmax: 3580 ng/mL [n = 7] and AUCtau: 19700 hr*ng/mL [n = 2]) was consistent with data from previous studies. Tx-related grade (GR) ≥3 adverse events (AEs) were more common in the combo (37.3%) vs pembro alone arm (16%). Tx-related AEs occurring in ≥10% of pts are shown in the Table. Tx discontinuation and dose adjustment/interruptions were more common in the combo (27.5% and 52.9%) vs pembro alone arm (16% and 16%). Capmatinib was stopped prematurely in the combo arm, and at DCO, 32 (62.7%) pts in the combo arm and 18 (72%) pts in the pembro alone arm were receiving pembro monotherapy. Conclusions: Combination tx with capmatinib and pembro was not well tolerated and did not improve antitumor activity in tx-naïve pts with advanced NSCLC with PD-L1 TPS ≥50%. Clinical trial information: NCT04139317. [Table: see text]

Case Report: A PD-L1-Positive Patient With Pleomorphic Rhabdomyosarcoma Achieving an Impressive Response to Immunotherapy

There is currently a lack of effective systemic treatment for patients with advanced pleomorphic rhabdomyosarcoma (PRMS). Although programmed death protein 1 (PD-1) inhibitors have shown efficacy in various solid tumors, their effects on PRMS have not been well established. Here, we present a case of a 12-year-old Chinese male adolescent with metastatic PRMS who benefited from the PD-1 inhibitor nivolumab. The patient initially underwent primary tumor resection but failed to respond to subsequent first-line chemotherapy and second-line pazopanib treatment. Pathological examination showed positive PD-L1 expression and tumor-infiltrating lymphocytes in the tumor tissue, and the patient was administered nivolumab as a posterior-line treatment. After attaining a clinically partial response (PR), surgical resection was performed, which was followed by adjuvant nivolumab. At the time of the submission of this manuscript, the patient achieved recurrence-free survival (RFS) lasting 45 months and counting. This is the first clinical evidence that a patient with refractory PRMS was controlled by anti-PD-1 antibody, with an RFS lasting more than 3 years. This case suggests that PD-L1 expression and T-cell infiltration could be used as potential biomarkers for PRMS immunotherapy.

Expanding the immunotherapy roadmap for hepatocellular carcinoma.

In a recent Lancet Oncology article, Yau etal. report the CheckMate 459 trial results. This is the first phase III trial comparing the single-agent anti-programmed death protein 1 (PD-1) therapy nivolumab to the tyrosine kinase inhibitor sorafenib for treatment-naive patients with advanced hepatocellular carcinoma.

Analysis of the efficacy and prognostic factors of PD-1 inhibitors in advanced gallbladder cancer.

BackgroundGallbladder cancer (GBC) is highly malignant, its early diagnosis is difficult, and the 5-year survival rate is less than 5%. For patients with advanced GBC (GBCa), combined chemotherapy, radiotherapy, targeted therapy, and immunotherapy are needed to improve the overall survival (OS) rate of patients.MethodsData were collected from 53 patients with GBCa who had volunteered to receive programmed death protein-1 (PD-1)-based treatment at the First Affiliated Hospital of Nanjing Medical University from February 2018 to February 2021. Statistical analysis of the collected data, including Kaplan-Meier method, log-rank test, Cox proportional hazard regression model and other methods.ResultsThe objective response rates (ORRs) and disease control rates (DCRs) of 53 participants 3 months after receiving immunotherapy were 30.2% and 79.2%, respectively. The ORRs and DCRs of the combined treatment group were higher than those of the camrelizumab group (CG) (P<0.05). The DCRs of the camrelizumab plus apatinib group (CAG) at 3 and 6 months were 90.9% and 45.5% (P=0.003), respectively, while the DCRs at 3 and 6 months of the camrelizumab plus chemotherapy group (CCG) were 85.7% and 71.4% (P=0.450), respectively. After treatment, there were statistically significant differences before and after CA199 for each group (P<0.05). The median progression-free survival (mPFS) of the 53 participants was 7 months, and the median overall survival (mOS) was 12 months. The mPFS and mOS of the CAG and the CCG were greater than those in the CG (6 vs. 3 months, P<0.001, 12 vs. 8 months, P=0.019; 9 vs. 3 months, P<0.001, 13 vs. 8 months, P<0.001, respectively). A total of 16 cases had grade 1 or 2 adverse events, and 3 cases had grade 3 and higher adverse events.ConclusionsFor GBCa patients, PD-1 combined with targeted therapy or chemotherapy is more effective than immunotherapy alone. The targeted therapy group has more obvious early effects on the disease control rate, and combined chemotherapy can achieve sustained effects, providing new ideas for the future GBCa application of immune, targeted, and chemotherapy sequential therapy.

Prognosis after liver transplantation in patients treated with anti- PD-1 immunotherapy for advanced hepatocellular carcinoma: case series

Programmed death protein-1 (PD-1) inhibitors and liver transplantation (LT) are alternative treatments for hepatocellular carcinoma (HCC) patients. The application of PD-1 inhibitors for HCC therapy increases T cell immune activity, while immunosuppression is required for patients receiving transplantation. More clinical investigation is required to determine methods to balance these treatment effects. In this article, we are the first to describe the clinical characteristics, imaging findings, and outcomes of 5 LT patients who had a history of HCC and received anti-PD-1 therapy. Data from 5 patients who were diagnosed with HCC and received LT after PD-1 inhibition were analyzed. The doses and courses of PD-1 and preoperative and postoperative characteristics were compared and analyzed. The mean interval between PD-1 inhibition and LT was 63.80±18.26 days. One patient experienced recurrence in the liver, vertebrae and lungs after 7 months, and 1 patient experienced recurrence in the lungs after 3 months. All patients displayed normal liver function at the latest follow-up visit. No acute allograft rejections occurred in any patient. PD-1 inhibitors may be safe for the treatment of HCC before LT when the interval between the two treatments is sufficient. Further investigations are needed for to validate these findings.

Abstract LB-184: The immunotherapeutic role of indoleamine 2,3-dioxygenase (IDO) in head and neck squamous cell carcinoma: a systematic review

Abstract Background: Novel cancer immunotherapy includes application of immune checkpoint inhibitors to the treatment of solid tumors. The body’s own immune system is thereby harnessed to tip the balance in favor of antitumor activity. The intracellular enzyme indoleamine 2,3-dioxygenase (IDO) is a critical regulator of the tumor microenvironment (TME) via tryptophan metabolism. Programmed death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) are immune checkpoints involved in T-cell inhibition and immunosuppression. Another immune checkpoint, IDO1, breaks down tryptophan into its metabolites which results in immunosuppression in the TME. Aim: To assess the evidence on IDO in head and neck squamous cell carcinoma (HNSCC). Methods: Medline, EMBASE using Ovid, Scopus, Web of Science, Cochrane Library databases, and ClinicalTrials.gov were searched from inception until present day. Results: We included 32 studies. Of those, 5 involved cell lines, 7 assessed tumor immunohistochemistry, 6 measured IDO gene transcription, and 14 reported on clinical trials. The human cell lines studied commonly were SCC4, SCC15, and SCC25 in which IDO expression and activation by the Stimulator of Interferon Genes (STING) pathway played a central role. Retrospective immunohistochemistry studies of lower lip, oral cavity, tongue, tonsil, and larynx found that relatively high IDO expression correlated with worse survival. Gene transcription studies showed increased IDO in tumors that expressed PD-L1 and harbored human papillomavirus (HPV). Phase I/II clinical trials showed 1) objective responses (34%) and disease control rates (62%) for IDO1 inhibitor in combination with a PD-1 inhibitor, 2) consistent safety profile in combination versus monotherapy, and 3) IDO gene expression as a predictive biomarker for response to PD-L1 therapy. Conclusions: IDO is integral to TME immunity in HNSCC particularly in HPV positive tumors, modulating existing therapies and application in combinatorial immunotherapy. Retrospective studies have shown the presence of IDO in the TME and suggest a link to prognosis and prediction of HNSCC treatment outcome. However, the exact mechanism of IDO-driven immune modulation in the HNSCC TME remains unclear. We now require prospective longitudinal studies to track IDO activity and expression throughout HNSCC treatment, thence optimise IDO-based immunotherapy. Citation Format: Daniel J. Lin, James C. Ng, Lei Huang, Max Robinson, James O'Hara, Janet A. Wilson, Andrew L. Mellor. The immunotherapeutic role of indoleamine 2,3-dioxygenase (IDO) in head and neck squamous cell carcinoma: a systematic review [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-184.

A Changing of the Guard: Immune Checkpoint Inhibitors With and Without Chemotherapy as First Line Treatment for Metastatic Non-small Cell Lung Cancer.

Inhibitory antibodies targeting programmed death protein 1 (PD-1) and programmed death ligand 1 (PD-L1) have resulted in improved outcomes for many patients with metastatic non-small cell lung cancer in (NSCLC) in the second-line setting due to their ability to lead to prolonged anti-tumor immune responses. Combining these immunotherapies with platinum-based chemotherapy as first-line treatment has resulted in improved response rates and increased survival when compared to platinum-based chemotherapy alone. Certain patient populations may even benefit from immune checkpoint inhibitors as monotherapy in the first-line setting. The PD-1 inhibitor pembrolizumab is approved as monotherapy or in combination with platinum + pemetrexed for most newly diagnosed patients with metastatic NSCLC, excluding those with a targetable oncogene such as ALK and EGFR. The PD-L1 inhibitor atezolizumab is also approved in combination with bevacizumab + carboplatin + paclitaxel for the same population, with some parts of the world also approving this regimen for patients with ALK rearrangements or EGFR activating mutations. However, there are many other chemo-immunotherapy regimens that have been evaluated as initial treatment in metastatic NSCLC. Additionally, combinations of PD-1 axis inhibitors with cytotoxic T lymphocyte antigen-4 inhibitors have been examined, although none are yet approved. Here we review the clinical data in support of the current first-line approaches across histologies and biomarker subtypes, as well as highlight future research directions revealed by the current data.

Pilot evaluation of PD-1 inhibition in metastatic cancer patients with a history of liver transplantation: the Mayo Clinic experience.

Patients with solid organ transplants (SOTs) have been excluded from programmed death protein-1 (PD-1)/programmed death ligand-1 (PD-L1) inhibitor clinical trials due to concern for allograft rejection. The use of immune checkpoint inhibitor therapy remains controversial in transplant patients. A retrospective pilot evaluation was conducted to assess the safety and efficacy of PD-1 inhibitors in patients with liver transplantation (LT). The primary endpoint was the rate of allograft rejection. Secondary endpoints included overall response rate (ORR), progression free survival (PFS) and overall survival (OS). Translational objectives included evaluation of tumor PD-L1, tumor infiltrating lymphocytes (TILs) and allograft PD-L1 expression. Seven metastatic cancer patients with a history of LT who received PD-1 inhibitor therapy were included [hepatocellular carcinoma (HCC), n=5; melanoma, n=2]. Rejection was observed in 2 of 7 patients. When rejection occurs it appears to be an early event with a median time to rejection of 24 days in our cohort. One patient achieved a complete response (CR), 3 patients had progressive disease (PD) and 3 patients discontinued therapy prior to restaging assessments. Two of five patients with available tissue had PD-L1 expression in the allograft and both developed rejection. One of five evaluable patients had abundant TILs. Two of five evaluable patients had PD-L1 tumor staining. The single patient with both abundant TILs and PD-L1 staining obtained a response. The median OS and PFS were 1.1 (0.3-21.1) and 1.8 (0.7-21.1) months, respectively. In this pilot evaluation both preliminary efficacy (1 of 4) and allograft rejection (2 of 7) were exhibited in evaluable patients. Larger, prospective trials are needed to elucidate optimal patient selection.