Faculty Bibliography

Lymph node metastasis in breast cancer depends in part on the acquisition of an IFN-dependent, MHC-II+ state that induces regulatory T cell expansion and local immune suppression (Lei et al. 2023. J. Exp. Med.https://doi.org/10.1084/jem.20221847).

Diffuse large B-cell lymphoma (DLBCL) is a typically immune suppressed lymphoma subtype with poor response to immune checkpoint blockade and CAR T cell therapy. Recent data demonstrated an association between an activated, myofibroblast-like tumor stroma with improved outcome. Based on these findings, Apollonio and colleagues explored the phenotypic, transcriptional, and functional state of fibroblastic reticular cells (FRC) in human and murine DLBCL. This study reveals that DLBCL cells trigger the activation and remodeling of FRCs, leading to a chronic inflammatory state that supports malignant B cell survival. Transcriptional reprogramming of the FRCs may inhibit CD8+ T cell migration and function through changes in homing chemokines, adhesion molecules, and antigen presentation machinery, which together limit the anti-DLBCL immune response. High-dimensional imaging mass cytometry revealed heterogeneous CD8+ T Cell and FRC neighborhoods that associated with different clinical outcomes and ex vivo modeling of the microenvironment indicated an opportunity to target the FRC network for improved T cell motility, infiltration, and effector function. This research broadens our understanding of the complex interactions between the lymph node microarchitecture and anti-tumor immune surveillance, defines structural vulnerabilities in DLBCL, and thereby offers opportunities for combined therapeutic approaches.

IMPORTANCE:Anti-programmable cell death-1 (anti-PD-1) improves relapse-free survival when used as adjuvant therapy for high-risk resected melanoma. However, it can lead to immune-related adverse events (irAEs), which become chronic in approximately 40% of patients with high-risk melanoma treated with adjuvant anti-PD-1. OBJECTIVE:To determine the incidence, characteristics, and long-term outcomes of chronic irAEs from adjuvant anti-PD-1 therapy. DESIGN, SETTING, AND PARTICIPANTS:This retrospective multicenter cohort study analyzed patients treated with adjuvant anti-PD-1 therapy for advanced and metastatic melanoma between 2015 and 2022 from 6 institutions in the US and Australia with at least 18 months of evaluable follow-up after treatment cessation (range, 18.2 to 70.4 months). MAIN OUTCOMES AND MEASURES:Incidence, spectrum, and ultimate resolution vs persistence of chronic irAEs (defined as those persisting at least 3 months after therapy cessation). Descriptive statistics were used to analyze categorical and continuous variables. Kaplan-Meier curves assessed survival, and Wilson score intervals were used to calculate CIs for proportions. RESULTS:Among 318 patients, 190 (59.7%) were male (median [IQR] age, 61 [52.3-72.0] years), 270 (84.9%) had a cutaneous primary, and 237 (74.5%) were stage IIIB or IIIC at presentation. Additionally, 226 patients (63.7%) developed acute irAEs arising during treatment, including 44 (13.8%) with grade 3 to 5 irAEs. Chronic irAEs, persisting at least 3 months after therapy cessation, developed in 147 patients (46.2%; 95% CI, 0.41-0.52), of which 74 (50.3%) were grade 2 or more, 6 (4.1%) were grade 3 to 5, and 100 (68.0%) were symptomatic. With long-term follow-up (median [IQR], 1057 [915-1321] days), 54 patients (36.7%) experienced resolution of chronic irAEs (median [IQR] time to resolution of 19.7 [14.4-31.5] months from anti-PD-1 start and 11.2 [8.1-20.7] months from anti-PD-1 cessation). Among patients with persistent irAEs present at last follow-up (93 [29.2%] of original cohort; 95% CI, 0.25-0.34); 55 (59.1%) were grade 2 or more; 41 (44.1%) were symptomatic; 24 (25.8%) were using therapeutic systemic steroids (16 [67%] of whom were on replacement steroids for hypophysitis (8 [50.0%]) and adrenal insufficiency (8 [50.0%]), and 42 (45.2%) were using other management. Among the 54 patients, the most common persistent chronic irAEs were hypothyroid (38 [70.4%]), arthritis (18 [33.3%]), dermatitis (9 [16.7%]), and adrenal insufficiency (8 [14.8%]). Furthermore, 54 [17.0%] patients experienced persistent endocrinopathies, 48 (15.1%) experienced nonendocrinopathies, and 9 (2.8%) experienced both. Of 37 patients with chronic irAEs who received additional immunotherapy, 25 (67.6%) experienced no effect on chronic irAEs whereas 12 (32.4%) experienced a flare in their chronic toxicity. Twenty patients (54.1%) experienced a distinct irAE. CONCLUSIONS AND RELEVANCE:In this cohort study of 318 patients who received adjuvant anti-PD-1, chronic irAEs were common, affected diverse organ systems, and often persisted with long-term follow-up requiring steroids and additional management. These findings highlight the likelihood of persistent toxic effects when considering adjuvant therapies and need for long-term monitoring and management.

BACKGROUND:Immune checkpoint inhibition (ICI) has improved clinical outcomes for metastatic melanoma patients; however, 65-80% of patients treated with ICI experience immune-related adverse events (irAEs). Given the plausible link of irAEs with underlying host immunity, we explored whether germline genetic variants controlling the expression of 42 immunomodulatory genes were associated with the risk of irAEs in melanoma patients treated with the single-agent anti-CTLA-4 antibody ipilimumab (IPI). METHODS:We identified 42 immunomodulatory expression quantitative trait loci (ieQTLs) most significantly associated with the expression of 382 immune-related genes. These germline variants were genotyped in IPI-treated melanoma patients, collected as part of a multi-institutional collaboration. We tested the association of ieQTLs with irAEs in a discovery cohort of 95 patients, followed by validation in an additional 97 patients. RESULTS:We found that the alternate allele of rs7036417, a variant linked to increased expression of SYK, was strongly associated with an increased risk of grade 3-4 toxicity [odds ratio (OR) = 7.46; 95% confidence interval (CI) = 2.65-21.03; p = 1.43E-04]. This variant was not associated with response (OR = 0.90; 95% CI = 0.37-2.21; p = 0.82). CONCLUSION/CONCLUSIONS:We report that rs7036417 is associated with increased risk of severe irAEs, independent of IPI efficacy. SYK plays an important role in B-cell/T-cell expansion, and increased pSYK has been reported in patients with autoimmune disease. The association between rs7036417 and IPI irAEs in our data suggests a role of SYK overexpression in irAE development. These findings support the hypothesis that inherited variation in immune-related pathways modulates ICI toxicity and suggests SYK as a possible future target for therapies to reduce irAEs.

Outcomes for patients with melanoma have improved over the past decade with the clinical development and approval of immunotherapies targeting immune checkpoint receptors such as programmed death-1 (PD-1), programmed death ligand 1 (PD-L1) or cytotoxic T lymphocyte antigen-4 (CTLA-4). Combinations of these checkpoint therapies with other agents are now being explored to improve outcomes and enhance benefit-risk profiles of treatment. Alternative inhibitory receptors have been identified that may be targeted for anti-tumor immune therapy, such as lymphocyte-activation gene-3 (LAG-3), as have several potential target oncogenes for molecularly targeted therapy, such as tyrosine kinase inhibitors. Unfortunately, many patients still progress and acquire resistance to immunotherapy and molecularly targeted therapies. To bypass resistance, combination treatment with immunotherapies and single or multiple TKIs have been shown to improve prognosis compared to monotherapy. The number of new combinations treatment under development for melanoma provides options for the number of patients to achieve a therapeutic benefit. Many diagnostic and prognostic assays have begun to show clinical applicability providing additional tools to optimize and individualize treatments. However, the question on the optimal algorithm of first- and later-line therapies and the search for biomarkers to guide these decisions are still under investigation. This year, the Melanoma Bridge Congress (Dec 1^st-3rd, 2022, Naples, Italy) addressed the latest advances in melanoma research, focusing on themes of paramount importance for melanoma prevention, diagnosis and treatment. This included sessions dedicated to systems biology on immunotherapy, immunogenicity and gene expression profiling, biomarkers, and combination treatment strategies.

It is well established that immunosuppressed patients are at increased risk for poor outcomes (PO) from cutaneous squamous cell carcinoma (cSCC), including local recurrence (LR), nodal metastasis (NM), distant metastasis (DM), and disease-specific death (DSD). Defining PO risk is challenging but may be beneficial in guiding management. We aimed to define PO risk factors and evaluated their importance in immunosuppressed versus immunocompetent patients. We conducted a 4-year single-center retrospective review of patients with cSCC. Patient and tumor characteristics were evaluated in those that experienced PO. Immunosuppressed patients were ~ 11-fold more likely than immunocompetent patients to develop PO (10/85 vs. 15/1332, p < 0.0001). Among those with PO, immunosuppressed patients had diminished relapse free (p = 0.026) and progression free (p < 0.001) survival compared to immunocompetent. Immunosuppression was significantly associated with LR (p < 0.00001). Immunosuppressed patients were also more likely to develop NM, DM and experience DSD (p = 0.027). Mohs Appropriate Use Criteria was associated with NM, DM and DSD (p = 0.029), with area H tumors more likely to result in metastasis and death. In conclusion, immunosuppressed patients are more likely to develop LR, metastasis, and DSD from cSCC compared to immunocompetent patients. Immunosuppressed status was an independent risk factor for PO in this cohort and further considered for its inclusion in prognostication schema is warranted.

T cell position in the tumor microenvironment determines the probability of target encounter and tumor killing. CD8+ T cell exclusion from the tumor parenchyma is associated with poor response to immunotherapy, and yet the biology that underpins this distinct pattern remains unclear. Here we show that the vascular destabilizing factor angiopoietin-2 (ANGPT2) causes compromised vascular integrity in the tumor periphery, leading to impaired T cell infiltration to the tumor core. The spatial regulation of ANGPT2 in whole tumor cross-sections was analyzed in conjunction with T cell distribution, vascular integrity, and response to immunotherapy in syngeneic murine melanoma models. T cell exclusion was associated with ANGPT2 upregulation and elevated vascular leakage at the periphery of human and murine melanomas. Both pharmacological and genetic blockade of ANGPT2 promoted CD8+ T cell infiltration into the tumor core, exerting antitumor effects. Importantly, the reversal of T cell exclusion following ANGPT2 blockade not only enhanced response to anti-PD-1 immune checkpoint blockade therapy in immunogenic, therapy responsive mouse melanomas, but it also rendered non-responsive tumors susceptible to immunotherapy. Therapeutic response after ANGPT2 blockade, driven by improved CD8+ T cell infiltration to the tumor core, coincided with spatial TIE2 signaling activation and increased vascular integrity at the tumor periphery where endothelial expression of adhesion molecules was reduced. These data highlight ANGPT2/TIE2 signaling as a key mediator of T cell exclusion and a promising target to potentiate immune checkpoint blockade efficacy in melanoma.