Radiation and anti-PD-L1 synergize by stimulating a stem-like T cell population in the tumor-draining lymph node.

Radiotherapy (RT) and anti-PD-L1 synergize to enhance local and distant (abscopal) tumor control. However, clinical results in humans have been variable. With the goal of improving clinical outcomes, we investigated the underlying synergistic mechanism focusing on a CD8+ PD-1+ Tcf-1+ stem-like T cell subset in the tumor-draining lymph node (TdLN). Using murine melanoma models, we found that RT + anti-PD-L1 induces a novel differentiation program in the TdLN stem-like population which leads to their expansion and differentiation into effector cells within the tumor. Our data indicate that optimal synergy between RT + anti-PD-L1 is dependent on the TdLN stem-like T cell population as either blockade of TdLN egress or specific stem-like T cell depletion reduced tumor control. Together, these data demonstrate a multistep stimulation of stem-like T cells following combination therapy which is initiated in the TdLN and completed in the tumor.

Clinically relevant orthotopic pancreatic cancer models for adoptive T cell transfer therapy.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is an aggressive tumor. Prognosis is poor and survival is low in patients diagnosed with this disease, with a survival rate of ~12% at 5 years. Immunotherapy, including adoptive T cell transfer therapy, has not impacted the outcomes in patients with PDAC, due in part to the hostile tumor microenvironment (TME) which limits T cell trafficking and persistence. We posit that murine models serve as useful tools to study the fate of T cell therapy. Currently, genetically engineered mouse models (GEMMs) for PDAC are considered a "gold-standard" as they recapitulate many aspects of human disease. However, these models have limitations, including marked tumor variability across individual mice and the cost of colony maintenance. METHODS: Using flow cytometry and immunohistochemistry, we characterized the immunological features and trafficking patterns of adoptively transferred T cells in orthotopic PDAC (C57BL/6) models using two mouse cell lines, KPC-Luc and MT-5, isolated from C57BL/6 KPC-GEMM (KrasLSL-G12D/+p53-/- and KrasLSL-G12D/+p53LSL-R172H/+, respectively). RESULTS: The MT-5 orthotopic model best recapitulates the cellular and stromal features of the TME in the PDAC GEMM. In contrast, far more host immune cells infiltrate the KPC-Luc tumors, which have less stroma, although CD4+ and CD8+ T cells were similarly detected in the MT-5 tumors compared with KPC-GEMM in mice. Interestingly, we found that chimeric antigen receptor (CAR) T cells redirected to recognize mesothelin on these tumors that signal via CD3ζ and 41BB (Meso-41BBζ-CAR T cells) infiltrated the tumors of mice bearing stroma-devoid KPC-Luc orthotopic tumors, but not MT-5 tumors. CONCLUSIONS: Our data establish for the first time a reproducible and realistic clinical system useful for modeling stroma-rich and stroma-devoid PDAC tumors. These models shall serve an indepth study of how to overcome barriers that limit antitumor activity of adoptively transferred T cells.

IL15 and IL21: Better When Membrane-Tethered Together on Antitumor T Cells.

Systemic administration of homeostatic γ-chain cytokines mediates antitumor responses in some patients treated with adoptive immunotherapy. Yet many patients experience toxic side effects. New work presented herein suggests these limitations can be overcome by membrane-tethering IL15 and IL21 to T-cell products. This finding has major implications in advancing medicine. See related article by Nguyen et al., p. 1555.

Progressively Enhancing Stemness of Adoptively Transferred T Cells with PI3Kδ Blockade Improves Metabolism and Antitumor Immunity.

Generating stem-like memory T cells (TSCM) is a potential strategy to improve adoptive immunotherapy. Elucidating optimal ways to modulate signaling pathways that enrich TSCM properties could identify approaches to achieve this goal. We discovered herein that blocking the PI3Kδ pathway pharmaceutically to varying degrees can generate T cells with increasingly heightened stemness properties, based on the progressive enrichment of the transcription factors Tcf1 and Lef1. T cells with enhanced stemness features exhibited metabolic plasticity, marked by improved mitochondrial function and glucose uptake after tumor recognition. Conversely, T cells with low or medium stemness were less metabolically dynamic, vulnerable to antigen-induced cell death, and expressed more inhibitory checkpoint receptors. Only T-cell receptor-specific or chimeric antigen receptor (CAR)-specific T cells with high stemness persisted in vivo and mounted protective immunity to tumors. Likewise, the strongest level of PI3Kδ blockade in vitro generated human tumor-infiltrating lymphocytes and CAR T cells with elevated stemness properties, in turn bolstering their capacity to regress human solid tumors. The stemness level of T cells in vitro was important, ultimately impacting their efficacy in mice bearing three distinct solid tumors. Lef1 and Tcf1 sustained antitumor protection by donor high CD8+ TSCM or CD4+ Th17SCM, as deletion of either one compromised the therapeutic efficacy. Collectively, these findings highlight the importance of strategic modulation of PI3Kδ signaling in T cells to induce stemness and lasting protective responses to solid tumors. SIGNIFICANCE: Elevating T-cell stemness by progressively blocking PI3Kδ signaling during ex vivo manufacturing of adoptive cell therapies alters metabolic and functional properties to enhance antitumor immunity dependent on Tcf1 and Lef1.

FcγRIIB expressed on CD8+ T cells limits responsiveness to PD-1 checkpoint inhibition in cancer.

Checkpoint inhibition using Fc-containing monoclonal antibodies has emerged as a powerful therapeutic approach to augment antitumor immunity. We recently showed that FcγRIIB, the only inhibitory IgG-Fc receptor, is expressed on a population of highly differentiated effector CD8+ T cells in the tumors of mice and humans, raising the possibility that CD8+ T cell responses may be directly modulated by checkpoint inhibitor binding to T cell-expressed FcγRIIB. Here, we show that despite exhibiting strong proliferative and cytokine responses at baseline, human FcγRIIBpos CD8+ T cells exhibited reduced responsiveness to both PD-1 and CTLA-4 checkpoint inhibition as compared with FcγRIIBneg CD8+ T cells in vitro. Moreover, frequencies of FcγRIIBpos CD8+ T cells were reduced after treatment of patients with melanoma with nivolumab in vivo. This reduced responsiveness was FcγRIIB dependent, because conditional genetic deletion of FcγRIIB on tumor-specific CD8+ T cells improved response to checkpoint blockade in B16 and LLC mouse models of cancer. The limited responsiveness of FcγRIIBpos CD8+ T cells was also dependent on an intact Fc region of the checkpoint inhibitor, in that treatment with Fc-devoid anti-PD-1 F(ab) fragments resulted in increased proliferation of FcγRIIBpos CD8+ T cells, without altering the response of FcγRIIBneg CD8+ T cells. Last, the addition of FcγRIIB blockade improved efficacy of PD-1 checkpoint inhibition in mouse models of melanoma, lung, and colon cancer. These results illuminate an FcγRIIB-mediated, cell-autonomous mechanism of CD8+ T cell suppression, which limits the efficacy of checkpoint inhibitors during antitumor immune responses in vivo.

Perspectives in Immunotherapy: meeting report from Immunotherapy Bridge (Naples, November 30th-December 1st, 2022).

The discovery and development of novel treatments that harness the patient's immune system and prevent immune escape has dramatically improved outcomes for patients across cancer types. However, not all patients respond to immunotherapy, acquired resistance remains a challenge, and responses are poor in certain tumors which are considered to be immunologically cold. This has led to the need for new immunotherapy-based approaches, including adoptive cell transfer (ACT), therapeutic vaccines, and novel immune checkpoint inhibitors. These new approaches are focused on patients with an inadequate response to current treatments, with emerging evidence of improved responses in various cancers with new immunotherapy agents, often in combinations with existing agents. The use of cell therapies, drivers of immune response, and trends in immunotherapy were the focus of the Immunotherapy Bridge (November 30th-December 1st, 2022), organized by the Fondazione Melanoma Onlus, Naples, Italy, in collaboration with the Society for Immunotherapy of Cancer.

The magic of small-molecule drugs during ex vivo expansion in adoptive cell therapy.

In the past decades, advances in the use of adoptive cellular therapy to treat cancer have led to unprecedented responses in patients with relapsed/refractory or late-stage malignancies. However, cellular exhaustion and senescence limit the efficacy of FDA-approved T-cell therapies in patients with hematologic malignancies and the widespread application of this approach in treating patients with solid tumors. Investigators are addressing the current obstacles by focusing on the manufacturing process of effector T cells, including engineering approaches and ex vivo expansion strategies to regulate T-cell differentiation. Here we reviewed the current small-molecule strategies to enhance T-cell expansion, persistence, and functionality during ex vivo manufacturing. We further discussed the synergistic benefits of the dual-targeting approaches and proposed novel vasoactive intestinal peptide receptor antagonists (VIPR-ANT) peptides as emerging candidates to enhance cell-based immunotherapy.

Potential clinical implications of CD4+CD26high T cells for nivolumab treated melanoma patients.

BACKGROUND: Nivolumab is an anti-PD1 antibody that has dramatically improved metastatic melanoma patients' outcomes. Nevertheless, many patients are resistant to PD-1 inhibition, occasionally experiencing severe off-target immune toxicity. In addition, no robust and reproducible biomarkers have yet been validated to identify the correct selection of patients who will benefit from anti-PD-1 treatment avoiding unwanted side effects. However, the strength of CD26 expression on CD4+ T lymphocytes permits the characterization of three subtypes with variable degrees of responsiveness to tumors, suggesting that the presence of CD26-expressing T cells in patients might be a marker of responsiveness to PD-1-based therapies. METHODS: The frequency distribution of peripheral blood CD26-expressing cells was investigated employing multi-parametric flow cytometry in 69 metastatic melanoma patients along with clinical characteristics and blood count parameters at baseline (W0) and compared to 20 age- and sex-matched healthy controls. Percentages of baseline CD4+CD26high T cells were correlated with the outcome after nivolumab treatment. In addition, the frequency of CD4+CD26high T cells at W0 was compared with those obtained after 12 weeks (W1) of therapy in a sub-cohort of 33 patients. RESULTS: Circulating CD4+CD26high T cells were significantly reduced in melanoma patients compared to healthy subjects (p = 0.001). In addition, a significant association was observed between a low baseline percentage of CD4+CD26high T cells (< 7.3%) and clinical outcomes, measured as overall survival (p = 0.010) and progression-free survival (p = 0.014). Moreover, patients with clinical benefit from nivolumab therapy had significantly higher frequencies of circulating CD4+CD26high T cells than patients with non-clinical benefit (p = 0.004) at 12 months. Also, a higher pre-treatment proportion of circulating CD4+CD26high T cells was correlated with Disease Control Rate (p = 0.014) and best Overall Response Rate (p = 0.009) at 12 months. Interestingly, after 12 weeks (W1) of nivolumab treatment, percentages of CD4+CD26high T cells were significantly higher in comparison with the frequencies measured at W0 (p < 0.0001), aligning the cell counts with the ranges seen in the blood of healthy subjects. CONCLUSIONS: Our study firstly demonstrates that peripheral blood circulating CD4+CD26high T lymphocytes represent potential biomarkers whose perturbations are associated with reduced survival and worse clinical outcomes in melanoma patients.

Does non-metastatic gastric cancer of the cardia warrant a different treatment strategy?

BACKGROUND: Multimodal treatment strategies with surgery as its centerpiece have been accepted as the standard of care in nonmetastatic cardia gastric cancer (CGC). There remains a lack of consensus regarding the optimal multimodal treatment strategy. METHOD: We queried National Cancer Database from 2004 to 2016 to identify patients with resected nonmetastatic CGC who received perioperative chemotherapy (PEC), postoperative chemoradiation therapy (POCR), or postoperative chemotherapy (POC). A subgroup analysis was performed in optimally treated patients defined as initial chemotherapy within 45 days of diagnosis, resection within 45 days of diagnosis, negative margins, adjuvant chemotherapy within 90 days of resection, and standard radiation dose (45 Gy). Kaplan-Meier, Univariate analysis (UVA), and Multivariable analysis (MVA) were performed. RESULTS: We identified 2387 patients. Median survival was 38.8 months in the PEC group, 36 months in the POCR group, and 32.3 months in the POC group (p = 0.1025). On UVA, patients treated with PEC had an association with improved survival (HR, 0.83; p = 0.037) when compared with POC. On MVA, no significant difference was noted in overall survival (OS) between PEC, POCR, and POC, similar to subgroup analysis of optimally treated cohort. CONCLUSION: OS rate in nonmetastatic CGC is not significantly different between patients receiving PEC, POCR, or POC.

Impact of nodal status in determining multimodal treatment strategies in non-cardia gastric cancer.

BACKGROUND: Patients with resectable noncardia gastric cancer may be subjected to perioperative chemotherapy (PEC), postoperative chemoradiation (POCR), or postoperative chemotherapy (POC). We analyzed these treatment strategies to determine optimal therapy based on nodal status. METHOD: The National Cancer Database was used to identify patients with resected noncardia gastric cancer (2004-2016). Patients were stratified based on clinical nodal status-negative (cLN-), positive (cLN+) and pathological nodal status (pLN-, pLN+). In cLN- patients who underwent upfront resection and were upstaged to pLN+, POC, and POCR were compared. Overall survival (OS) with PEC, POCR, and POC were compared in cLN- and cLN+. RESULTS: We identified 6142 patients (cLN-: 3831; cLN+: 2311). In cLN- patients who underwent upfront resection (N = 3423), 69% were upstaged to pLN+ disease (N = 2499; POCR = 1796, POC = 703). On MVA, POCR was associated with significantly improved OS when compared to POC (hazard ratio [HR]: 0.75; p < 0.001). In patients with cLN- disease (PEC = 408; POCR = 2439; POC = 984), PEC(HR: 0.77; p = 0.01) and POCR(HR: 0.81; p < 0.001) were associated with improved OS compared with POC. In cLN+ group (PEC = 452; POCR = 1284; POC = 575), POCR was associated with improved OS compared with POC (HR: 0.81; p < 0.01), and trend towards improved OS was noted when PEC(HR: 0.83; p = 0.055) was compared with POC. CONCLUSION: Postoperative chemoradiation may be the preferred treatment strategy over postoperative chemotherapy in non-cardia gastric cancer patients who receive upfront resection and are upstaged from clinically node negative to pathologically node positive disease.

Augmenting TCR signal strength and ICOS costimulation results in metabolically fit and therapeutically potent human CAR Th17 cells.

IL-17-producing antigen-specific human T cells elicit potent antitumor activity in mice. Yet, refinement of this approach is needed to position it for clinical use. While activation signal strength regulates IL-17 production by CD4+ T cells, the degree to which T cell antigen receptor (TCR) and costimulation signal strength influences Th17 immunity remains unknown. We discovered that decreasing TCR/costimulation signal strength by incremental reduction of αCD3/costimulation beads progressively altered Th17 phenotype. Moreover, Th17 cells stimulated with αCD3/inducible costimulator (ICOS) beads produced more IL-17A, IFNγ, IL-2, and IL-22 than those stimulated with αCD3/CD28 beads. Compared with Th17 cells stimulated with the standard, strong signal strength (three beads per T cell), Th17 cells propagated with 30-fold fewer αCD3/ICOS beads were less reliant on glucose and favored the central carbon pathway for bioenergetics, marked by abundant intracellular phosphoenolpyruvate (PEP). Importantly, Th17 cells stimulated with weak αCD3/ICOS beads and redirected with a chimeric antigen receptor that recognizes mesothelin were more effective at clearing human mesothelioma. Less effective CAR Th17 cells generated with high αCD3/ICOS beads were rescued by overexpressing phosphoenolpyruvate carboxykinase 1 (PCK1), a PEP regulator. Thus, Th17 therapy can be improved by using fewer activation beads during manufacturing, a finding that is cost effective and directly translatable to patients.

Dual IL-6 and CTLA-4 blockade regresses pancreatic tumors in a T cell- and CXCR3-dependent manner.

This study aimed to enhance antitumor immune responses to pancreatic cancer via Ab-based blockade of IL-6 and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). Mice bearing s.c. or orthotopic pancreatic tumors were treated with blocking Abs to IL­6 and/or CTLA-4. In both tumor models, dual IL-6 and CTLA-4 blockade significantly inhibited tumor growth. Additional investigations revealed that dual therapy induced an overwhelming infiltration of T cells into the tumor as well as changes in CD4+ T cell subsets. Dual blockade therapy elicited CD4+ T cells to secrete increased IFN-γ in vitro. Likewise, in vitro stimulation of pancreatic tumor cells with IFN-γ profoundly increased tumor cell production of CXCR3-specific chemokines, even in the presence of IL-6. In vivo blockade of CXCR3 prevented orthotopic tumor regression in the presence of the combination treatment, demonstrating a dependence on the CXCR3 axis for antitumor efficacy. Both CD4+ and CD8+ T cells were required for the antitumor activity of this combination therapy, as their in vivo depletion via Abs impaired outcomes. These data represent the first report to our knowledge of IL-6 and CTLA­4 blockade as a means to regress pancreatic tumors with defined operative mechanisms of efficacy.

The degree of T cell stemness differentially impacts the potency of adoptive cancer immunotherapy in a Lef-1 and Tcf-1 dependent manner.

Generating stem memory T cells (T SCM ) is a key goal for improving cancer immunotherapy. Yet, the optimal way to modulate signaling pathways that enrich T SCM properties remains elusive. Here, we discovered that the degree to which the PI3Kδ pathway is blocked pharmaceutically can generate T cells with differential levels of stemness properties. This observation was based on the progressive enrichment of transcriptional factors of stemness (Tcf-1 and Lef-1). Additional investigation revealed that T cells with high stemness features had enhanced metabolic plasticity, marked by heightened mitochondrial function and glucose uptake. Conversely, T cells with low or medium features of stemness expressed more inhibitory checkpoint receptors (Tim-3, CD39) and were vulnerable to antigen-induced cell death. Only TCR-antigen specific T cells with high stemness persisted following adoptive transfer in vivo and mounted protective immunity to melanoma tumors. Likewise, the strongest level of PI3Kδ blockade in vitro generated human tumor infiltrating lymphocytes (TILs) and CAR T cells with heightened stemness properties, in turn bolstering their capacity to regress human mesothelioma tumors. We find that the level of stemness T cells possess in vitro differentially impacts their potency upon transfer in three tumor models. Mechanistically, both Lef-1 and Tcf-1 sustain anti-tumor protection by high T SCM , as deletion of either one compromised cellular therapy. Collectively, these findings highlight the therapeutic potential of carefully modulating PI3Kδ signaling in T cells to confer high stemness and mediate protective responses to solid tumors.

Adhesion analysis via a tumor vasculature-like microfluidic device identifies CD8+ T cells with enhanced tumor homing to improve cell therapy.

CD8+ T cell recruitment to the tumor microenvironment is critical for the success of adoptive cell therapy (ACT). Unfortunately, only a small fraction of transferred cells home to solid tumors. Adhesive ligand-receptor interactions have been implicated in CD8+ T cell homing; however, there is a lack of understanding of how CD8+ T cells interact with tumor vasculature-expressed adhesive ligands under the influence of hemodynamic flow. Here, the capacity of CD8+ T cells to home to melanomas is modeled ex vivo using an engineered microfluidic device that recapitulates the hemodynamic microenvironment of the tumor vasculature. Adoptively transferred CD8+ T cells with enhanced adhesion in flow in vitro and tumor homing in vivo improve tumor control by ACT in combination with immune checkpoint blockade. These results show that engineered microfluidic devices can model the microenvironment of the tumor vasculature to identify subsets of T cells with enhanced tumor infiltrating capabilities, a key limitation in ACT.

Distinct host preconditioning regimens differentially impact the antitumor potency of adoptively transferred Th17 cells.

Background: Mechanisms by which distinct methods of host preconditioning impact the efficacy of adoptively transferred antitumor T helper cells is unknown. Methods: CD4 + T cells with a transgenic TCR that recognize TRP-1 melanoma antigen were polarized to the T helper 17 (Th17) phenotype and then transferred into melanoma-bearing mice preconditioned with either total body irradiation or chemotherapy. Results: We found that preconditioning mice with a non-myeloablative dose of total body irradiation (TBI of 5 Gy) was more effective than using an equivalently dosed non-myeloablative chemotherapy (CTX at 200 mg/kg) at augmenting therapeutic activity of anti-tumor TRP-1 Th17 cells. Anti-tumor Th17 cells engrafted better following preconditioning with TBI and regressed large established melanoma in all animals. Conversely, only half of mice survived long-term when preconditioned with CTX and infused with anti-melanoma Th17 cells. IL-17 and IFN-g produced by the infused Th17 cells, were detected in animals given either TBI or CTX preconditioning. Interestingly, inflammatory cytokines (G-CSF, IL-6, MCP-1, IL-5, and KC) were significantly elevated in the serum of mice preconditioned with TBI versus CTX after Th17 therapy. Conclusions: Our results indicate, for the first time, that the antitumor response, persistence, and cytokine profiles resulting from Th17 therapy are impacted by the specific regimen of host preconditioning. This work is important for understanding mechanisms that promote long-lived responses by ACT, particularly as CD4 + based T cell therapies are now emerging in the clinic.

Stress-Mediated Attenuation of Translation Undermines T-cell Activity in Cancer.

Protein synthesis supports robust immune responses. Nutrient competition and global cell stressors in the tumor microenvironment (TME) may impact protein translation in T cells and antitumor immunity. Using human and mouse tumors, we demonstrated here that protein translation in T cells is repressed in solid tumors. Reduced glucose availability to T cells in the TME led to activation of the unfolded protein response (UPR) element eIF2α (eukaryotic translation initiation factor 2 alpha). Genetic mouse models revealed that translation attenuation mediated by activated p-eIF2α undermines the ability of T cells to suppress tumor growth. Reprograming T-cell metabolism was able to alleviate p-eIF2α accumulation and translational attenuation in the TME, allowing for sustained protein translation. Metabolic and pharmacological approaches showed that proteasome activity mitigates induction of p-eIF2α to support optimal antitumor T-cell function, protecting from translation attenuation and enabling prolonged cytokine synthesis in solid tumors. Together, these data identify a new therapeutic avenue to fuel the efficacy of tumor immunotherapy. SIGNIFICANCE: Proteasome function is a necessary cellular component for endowing T cells with tumor killing capacity by mitigating translation attenuation resulting from the unfolded protein response induced by stress in the tumor microenvironment.

Programmed death 1 (PD-1) and ligand (PD-L1) inhibitors in head and neck squamous cell carcinoma: A meta-analysis.

Background: PD-1 and PD-L1 inhibitors have emerged as promising treatments for patients with head and neck squamous cell carcinoma (HNSCC). Methods: Systematic review and meta-analysis of PD-1 and PD-L1 inhibitors in HNSCC. Outcomes: median overall survival (mOS), median progression-free survival (mPFS), Response Evaluation Criteria in Solid Tumors (RECIST) and treatment-related adverse events (TRAEs). Results: Eleven trials reported data on 1088 patients (mean age: 59.9 years, range: 18-90). The total mOS was 7.97 months (range: 6.0-16.5). Mean mPFS for all studies was 2.84 months (range: 1.9-6.5). PD-1 inhibitors had a lower rate of RECIST Progressive Disease than PD-L1 inhibitors (42.61%, 95% confidence interval [CI]: 36.29-49.06 vs. 56.79%, 95% CI: 49.18-64.19, P < 0.001). The rate of TRAEs of any grade (62.7%, 95% CI: 59.8-65.6) did not differ. Conclusions: Meta-analysis shows the efficacy of PD-1 and PD-L1 inhibitors in HNSCC and suggests a possible difference in certain RECIST criterion between PD-1 and PD-L1 inhibitors. Future work to investigate the clinical significance of these findings is warranted.

Combined MEK/PD-L1 Inhibition Alters Peripheral Cytokines and Lymphocyte Populations Correlating with Improved Clinical Outcomes in Advanced Biliary Tract Cancer.

PURPOSE: Biliary tract cancers (BTC) are aggressive malignancies refractory to chemotherapy and immunotherapy. MEK inhibition (MEKi)-based regimens may have utility in this disease when combined with PD-L1 blockade. We hypothesize that dual MEK/PD-L1 inhibition alters circulating soluble and cellular immune mediators to improve clinical outcomes in patients with advanced BTC. EXPERIMENTAL DESIGN: We examined immune features in peripheral blood from 77 patients with advanced BTC enrolled in a phase II clinical trial investigating atezolizumab with or without cobimetinib. Plasma and peripheral blood mononuclear cells (PBMC) were isolated from whole blood to evaluate soluble factors and immune cell populations. Baseline blood samples were additionally compared with healthy donors to identify immune signatures unique to BTC. RESULTS: At baseline, the soluble factors platelet-derived growth factor B (PDGF)-BB, placental growth factor (PlGF)-1, IL5, and IL17A were elevated in patients with BTC compared with healthy adult donors, and higher baseline frequencies of CD8+BTLA+ T cells correlated with better overall survival (OS) in this trial. There were also significant treatment-related alterations in several factors, including decreased PDGF-BB following combination treatment, that correlated with improved OS and progression-free survival (PFS). Higher baseline levels of IL23 and RANTES corresponded to improved clinical outcomes following combination treatment. Dual MEK/PD-L1 inhibition increased populations of CD4+TIM3+ and decreased CD8+VISTA+ T cells, correlating with worse OS and better PFS, respectively. CONCLUSIONS: This work represents a comprehensive analysis of peripheral immune features in patients with BTC and systemic responses to dual MEK/PD-L1 inhibition. These data support further investigation to understand how MEKi combines with immunotherapeutic approaches to improve clinical outcomes for patients with advanced BTC.

Perspectives in Immunotherapy: meeting report from the Immunotherapy Bridge, December 1st-2nd, 2021.

Over the past decade, immunotherapy has become an increasingly fundamental modality in the treatment of cancer. The positive impact of immune checkpoint inhibition, especially anti-programmed death (PD)-1/PD-ligand (L)1 blockade, in patients with different cancers has focused attention on the potential for other immunotherapeutic approaches. These include inhibitors of additional immune checkpoints, adoptive cell transfer (ACT), and therapeutic vaccines. Patients with advanced cancers who previously had limited treatment options available may now benefit from immunotherapies that can offer durable responses and improved survival outcomes. However, despite this, a significant proportion of patients fail to respond to immunotherapy, especially those with less immunoresponsive cancer types, and there remains a need for new treatment strategies.The virtual Immunotherapy Bridge (December 1st-2nd, 2021), organized by the Fondazione Melanoma Onlus, Naples, Italy in collaboration with the Society for Immunotherapy of Cancer addressed several areas of current research in immunotherapy, including lessons learned from cell therapies, drivers of immune response, and trends in immunotherapy across different cancers, and these are summarised here.

Association of age with survival in older patients with cutaneous melanoma treated with immune checkpoint inhibitors.

INTRODUCTION: Several types of immune checkpoint inhibitors (ICIs) are approved to treat advanced melanoma, but their effectiveness has not been compared in older patients treated outside of a clinical trial. Moreover, evidence suggests that a patient's response to ICI therapy may vary by age and type of ICI. The purpose of this study was to compare survival by ICI type in older patients with melanoma and to investigate treatment effect modification by age. MATERIALS AND METHODS: Using the SEER-Medicare database, we identified patients with cutaneous melanoma (2012-2015) treated with an ICI (CTLA-4, PD-1, or combination CTLA-4 + PD-1 inhibitors). Cox proportional hazards regression was used to estimate hazard ratios (HRs) with 95% confidence intervals (CI) for ICI types. We used an interaction term and stratified models to test for treatment effect modification by age. RESULTS: Of the 1435 patients included in our analysis, 790 (55.1%) received CTLA-4 inhibitors, 512 (35.7%) received PD-1 inhibitors, and 133 (9.3%) were treated with combination ICIs. Median survival ranged from 13.4 months (95%CI: 10.7-16.3) for CTLA-4 inhibitors to 23.5 months (95%CI: 16.2-30.0) for combination ICIs. In multivariable models, the risk of death was lower with PD-1 inhibitors compared to CTLA-4 inhibitors (HR = 0.78, 95%CI: 0.68-0.89). An age*ICI type interaction term was significant (p < 0.001), and survival gains were greater the older age group (≥80) compared to the younger group (65-79). DISCUSSION: In a population-based setting, we identified important differences in survival by ICI type in older patients with melanoma treated with ICIs, with prolonged survival associated with PD-1 inhibitors compared to CTLA-4 inhibitors.