Immune checkpoint therapy-current perspectives and future directions.

Immune checkpoint therapy (ICT) has dramatically altered clinical outcomes for cancer patients and conferred durable clinical benefits, including cure in a subset of patients. Varying response rates across tumor types and the need for predictive biomarkers to optimize patient selection to maximize efficacy and minimize toxicities prompted efforts to unravel immune and non-immune factors regulating the responses to ICT. This review highlights the biology of anti-tumor immunity underlying response and resistance to ICT, discusses efforts to address the current challenges with ICT, and outlines strategies to guide the development of subsequent clinical trials and combinatorial efforts with ICT.

Distinct Cellular Mechanisms Underlie Anti-CTLA-4 and Anti-PD-1 Checkpoint Blockade.

Immune-checkpoint blockade is able to achieve durable responses in a subset of patients; however, we lack a satisfying comprehension of the underlying mechanisms of anti-CTLA-4- and anti-PD-1-induced tumor rejection. To address these issues, we utilized mass cytometry to comprehensively profile the effects of checkpoint blockade on tumor immune infiltrates in human melanoma and murine tumor models. These analyses reveal a spectrum of tumor-infiltrating T cell populations that are highly similar between tumor models and indicate that checkpoint blockade targets only specific subsets of tumor-infiltrating T cell populations. Anti-PD-1 predominantly induces the expansion of specific tumor-infiltrating exhausted-like CD8 T cell subsets. In contrast, anti-CTLA-4 induces the expansion of an ICOS+ Th1-like CD4 effector population in addition to engaging specific subsets of exhausted-like CD8 T cells. Thus, our findings indicate that anti-CTLA-4 and anti-PD-1 checkpoint-blockade-induced immune responses are driven by distinct cellular mechanisms.

Loss of IFN-γ Pathway Genes in Tumor Cells as a Mechanism of Resistance to Anti-CTLA-4 Therapy.

Antibody blockade of the inhibitory CTLA-4 pathway has led to clinical benefit in a subset of patients with metastatic melanoma. Anti-CTLA-4 enhances T cell responses, including production of IFN-γ, which is a critical cytokine for host immune responses. However, the role of IFN-γ signaling in tumor cells in the setting of anti-CTLA-4 therapy remains unknown. Here, we demonstrate that patients identified as non-responders to anti-CTLA-4 (ipilimumab) have tumors with genomic defects in IFN-γ pathway genes. Furthermore, mice bearing melanoma tumors with knockdown of IFN-γ receptor 1 (IFNGR1) have impaired tumor rejection upon anti-CTLA-4 therapy. These data highlight that loss of the IFN-γ signaling pathway is associated with primary resistance to anti-CTLA-4 therapy. Our findings demonstrate the importance of tumor genomic data, especially IFN-γ related genes, as prognostic information for patients selected to receive treatment with immune checkpoint therapy.

Immune checkpoint targeting in cancer therapy: toward combination strategies with curative potential.

Research in two fronts has enabled the development of therapies that provide significant benefit to cancer patients. One area stems from a detailed knowledge of mutations that activate or inactivate signaling pathways that drive cancer development. This work triggered the development of targeted therapies that lead to clinical responses in the majority of patients bearing the targeted mutation, although responses are often of limited duration. In the second front are the advances in molecular immunology that unveiled the complexity of the mechanisms regulating cellular immune responses. These developments led to the successful targeting of immune checkpoints to unleash anti-tumor T cell responses, resulting in durable long-lasting responses but only in a fraction of patients. In this Review, we discuss the evolution of research in these two areas and propose that intercrossing them and increasing funding to guide research of combination of agents represent a path forward for the development of curative therapies for the majority of cancer patients.

Negative Co-stimulation Constrains T Cell Differentiation by Imposing Boundaries on Possible Cell States.

Co-stimulation regulates T cell activation, but it remains unclear whether co-stimulatory pathways also control T cell differentiation. We used mass cytometry to profile T cells generated in the genetic absence of the negative co-stimulatory molecules CTLA-4 and PD-1. Our data indicate that negative co-stimulation constrains the possible cell states that peripheral T cells can acquire. CTLA-4 imposes major boundaries on CD4+ T cell phenotypes, whereas PD-1 subtly limits CD8+ T cell phenotypes. By computationally reconstructing T cell differentiation paths, we identified protein expression changes that underlied the abnormal phenotypic expansion and pinpointed when lineage choice events occurred during differentiation. Similar alterations in T cell phenotypes were observed after anti-CTLA-4 and anti-PD-1 antibody blockade. These findings implicate negative co-stimulation as a key regulator and determinant of T cell differentiation and suggest that checkpoint blockade might work in part by altering the limits of T cell phenotypes.

T cells specific for α-myosin drive immunotherapy-related myocarditis.

Immune-related adverse events, particularly severe toxicities such as myocarditis, are major challenges to the utility of immune checkpoint inhibitors (ICIs) in anticancer therapy1. The pathogenesis of ICI-associated myocarditis (ICI-MC) is poorly understood. Pdcd1-/-Ctla4+/- mice recapitulate clinicopathological features of ICI-MC, including myocardial T cell infiltration2. Here, using single-cell RNA and T cell receptor (TCR) sequencing of cardiac immune infiltrates from Pdcd1-/-Ctla4+/- mice, we identify clonal effector CD8+ T cells as the dominant cell population. Treatment with anti-CD8-depleting, but not anti-CD4-depleting, antibodies improved the survival of Pdcd1-/-Ctla4+/- mice. Adoptive transfer of immune cells from mice with myocarditis induced fatal myocarditis in recipients, which required CD8+ T cells. The cardiac-specific protein α-myosin, which is absent from the thymus3,4, was identified as the cognate antigen source for three major histocompatibility complex class I-restricted TCRs derived from mice with fulminant myocarditis. Peripheral blood T cells from three patients with ICI-MC were expanded by α-myosin peptides. Moreover, these α-myosin-expanded T cells shared TCR clonotypes with diseased heart and skeletal muscle, which indicates that α-myosin may be a clinically important autoantigen in ICI-MC. These studies underscore the crucial role for cytotoxic CD8+ T cells, identify a candidate autoantigen in ICI-MC and yield new insights into the pathogenesis of ICI toxicity.

Neoadjuvant relatlimab and nivolumab in resectable melanoma.

Relatlimab and nivolumab combination immunotherapy improves progression-free survival over nivolumab monotherapy in patients with unresectable advanced melanoma1. We investigated this regimen in patients with resectable clinical stage III or oligometastatic stage IV melanoma (NCT02519322). Patients received two neoadjuvant doses (nivolumab 480 mg and relatlimab 160 mg intravenously every 4 weeks) followed by surgery, and then ten doses of adjuvant combination therapy. The primary end point was pathologic complete response (pCR) rate2. The combination resulted in 57% pCR rate and 70% overall pathologic response rate among 30 patients treated. The radiographic response rate using Response Evaluation Criteria in Solid Tumors 1.1 was 57%. No grade 3-4 immune-related adverse events were observed in the neoadjuvant setting. The 1- and 2-year recurrence-free survival rate was 100% and 92% for patients with any pathologic response, compared to 88% and 55% for patients who did not have a pathologic response (P = 0.005). Increased immune cell infiltration at baseline, and decrease in M2 macrophages during treatment, were associated with pathologic response. Our results indicate that neoadjuvant relatlimab and nivolumab induces a high pCR rate. Safety during neoadjuvant therapy is favourable compared to other combination immunotherapy regimens. These data, in combination with the results of the RELATIVITY-047 trial1, provide further confirmation of the efficacy and safety of this new immunotherapy regimen.

Post-immunotherapy CTLA-4 Ig treatment improves antitumor efficacy.

Immune checkpoint therapies (ICT) improve overall survival of patients with cancer but may cause immune-related adverse events (irAEs) such as myocarditis. Cytotoxic T lymphocyte-associated antigen 4 immunoglobulin fusion protein (CTLA-4 Ig), an inhibitor of T cell costimulation through CD28, reverses irAEs in animal models. However, concerns exist about potentially compromising antitumor response of ICT. In mouse tumor models, we administered CTLA-4 Ig 1) concomitantly with ICT or 2) after ICT completion. Concomitant treatment reduced antitumor efficacy, while post-ICT administration improved efficacy without affecting frequency and function of CD8 T cells. The improved response was independent of the ICT used, whether CTLA-4 or PD-1 blockade. The frequency of Tregs was significantly decreased with CTLA-4 Ig. The resulting increased CD8/Treg ratio potentially underlies the enhanced efficacy of ICT followed by CTLA-4 Ig. This paradoxical mechanism shows that a CTLA-4 Ig regimen shown to reduce irAE severity does not compromise antitumor efficacy.

An efficient strategy for evaluating new non-invasive screening tests for colorectal cancer: the guiding principles.

OBJECTIVE: New screening tests for colorectal cancer (CRC) are rapidly emerging. Conducting trials with mortality reduction as the end point supporting their adoption is challenging. We re-examined the principles underlying evaluation of new non-invasive tests in view of technological developments and identification of new biomarkers. DESIGN: A formal consensus approach involving a multidisciplinary expert panel revised eight previously established principles. RESULTS: Twelve newly stated principles emerged. Effectiveness of a new test can be evaluated by comparison with a proven comparator non-invasive test. The faecal immunochemical test is now considered the appropriate comparator, while colonoscopy remains the diagnostic standard. For a new test to be able to meet differing screening goals and regulatory requirements, flexibility to adjust its positivity threshold is desirable. A rigorous and efficient four-phased approach is proposed, commencing with small studies assessing the test's ability to discriminate between CRC and non-cancer states (phase I), followed by prospective estimation of accuracy across the continuum of neoplastic lesions in neoplasia-enriched populations (phase II). If these show promise, a provisional test positivity threshold is set before evaluation in typical screening populations. Phase III prospective studies determine single round intention-to-screen programme outcomes and confirm the test positivity threshold. Phase IV studies involve evaluation over repeated screening rounds with monitoring for missed lesions. Phases III and IV findings will provide the real-world data required to model test impact on CRC mortality and incidence. CONCLUSION: New non-invasive tests can be efficiently evaluated by a rigorous phased comparative approach, generating data from unbiased populations that inform predictions of their health impact.

How dental teams can help patients with temporomandibular disorders receive general dental care: An International Delphi process.

BACKGROUND: Many patients with temporomandibular disorders (TMD) find it difficult to undergo dental care due to challenges caused by their condition, previous temporomandibular joint surgery or invasive dental procedures, and the impact of comorbid conditions. Managing routine dental care for some patients with TMD can be seen as challenging by some dental practitioners. OBJECTIVE: The objective of this study was to work with patients experiencing TMD and clinicians to co-produce recommendations aimed at helping general dentists to provide routine dental care for patients with TMD. METHODS: A modified Delphi process was used to co-produce recommendations. Six patients experiencing TMD, patient advocates and seven clinicians took part, including international TMD clinicians. Two meetings were held with patient participants, mediated by a trained facilitator. Recommendations suggested by patient participants were distributed to clinicians who were asked to add additional suggestions, but not to modify patients' recommendations unless to aid clarity. Additional themes were identified from the existing literature, and the recommendations were then reviewed by the International Network for Orofacial Pain and Related Disorders Methodology (INfORM) consortium. RESULTS: Recommendations were given to support patients before, during and after dental treatment. Participants identified specific and practical recommendations to help patients with TMD receive routine dental care, but also emphasised the need for professionals to listen sensitively to patients' concerns and work with patients in an empathetic and non-judgmental way. CONCLUSION: These recommendations, co-developed with patients experiencing TMD, should help dental professionals to provide supportive general dental care for patients with TMD.

TLR1/2 ligand enhances antitumor efficacy of CTLA-4 blockade by increasing intratumoral Treg depletion.

Immune checkpoint inhibitors such as anti-CTLA-4 antibody are widely accepted therapeutic options for many cancers, but there is still a considerable gap in achieving their full potential. We explored the potential of activating the innate and adaptive immune pathways together to improve tumor reduction and survival outcomes. We treated a mouse model of melanoma with intratumoral injections of Toll-like receptor 1/2 (TLR1/2) ligand Pam3CSK4 plus i.p. injections of anti-CTLA-4 antibody. This combination treatment enhanced antitumor immune responses both qualitatively and quantitatively over anti-CTLA-4 alone, and its efficacy depended on CD4 T cells, CD8 T cells, Fcγ receptor IV, and macrophages. Interestingly, our results suggest a unique mechanism by which TLR1/2 ligand increased Fcγ receptor IV expression on macrophages, leading to antibody-dependent macrophage-mediated depletion of regulatory T cells in the tumor microenvironment and increasing efficacy of anti-CTLA-4 antibody in the combination treatment. This mechanism could be harnessed to modulate the clinical outcome of anti-CTLA-4 antibodies and possibly other antibody-based immunotherapies.

Combination anti-CTLA-4 plus anti-PD-1 checkpoint blockade utilizes cellular mechanisms partially distinct from monotherapies.

Immune checkpoint blockade therapy targets T cell-negative costimulatory molecules such as cytotoxic T lymphocyte antigen-4 (CTLA-4) and programmed cell death-1 (PD-1). Combination anti-CTLA-4 and anti-PD-1 blockade therapy has enhanced efficacy, but it remains unclear through what mechanisms such effects are mediated. A critical question is whether combination therapy targets and modulates the same T cell populations as monotherapies. Using a mass cytometry-based systems approach, we comprehensively profiled the response of T cell populations to monotherapy and combination anti-CTLA-4 plus anti-PD-1 therapy in syngeneic murine tumors and clinical samples. Most effects of monotherapies were additive in the context of combination therapy; however, multiple combination therapy-specific effects were observed. Highly phenotypically exhausted cluster of differentiation 8 (CD8) T cells expand in frequency following anti-PD-1 monotherapy but not combination therapy, while activated terminally differentiated effector CD8 T cells expand only following combination therapy. Combination therapy also led to further increased frequency of T helper type 1 (Th1)-like CD4 effector T cells even though anti-PD-1 monotherapy is not sufficient to do so. Mass cytometry analyses of peripheral blood from melanoma patients treated with immune checkpoint blockade therapies similarly revealed mostly additive effects on the frequencies of T cell subsets along with unique modulation of terminally differentiated effector CD8 T cells by combination ipilimumab plus nivolumab therapy. Together, these findings indicate that dual blockade of CTLA-4 and PD-1 therapy is sufficient to induce unique cellular responses compared with either monotherapy.

Autoimmune antibodies correlate with immune checkpoint therapy-induced toxicities.

Immune checkpoint (IC) therapy provides substantial benefits to cancer patients but can also cause distinctive toxicities termed immune-related adverse events (irAEs). Biomarkers to predict toxicities will be necessary to improve management of patients receiving IC therapy. We relied on serological analysis of recombinant cDNA expression libraries to evaluate plasma samples from patients treated with IC therapy and identified autoantibodies, both in pretreatment and on-treatment samples prior to the development of irAEs, which correlate with the development of immune-related hypophysitis (anti-GNAL and anti-ITM2B autoantibodies) and pneumonitis (anti-CD74 autoantibody). We developed an enzyme-linked immunosorbent assay and tested additional patient samples to confirm our initial findings. Collectively, our data suggest that autoantibodies may correlate with irAEs related to IC therapy, and specific autoantibodies may be detected early for the management of irAEs.

Comparison of immune infiltrates in melanoma and pancreatic cancer highlights VISTA as a potential target in pancreatic cancer.

Immune checkpoint therapy (ICT) has transformed cancer treatment in recent years; however, treatment response is not uniform across tumor types. The tumor immune microenvironment plays a critical role in determining response to ICT; therefore, understanding the differential immune infiltration between ICT-sensitive and ICT-resistant tumor types will help to develop effective treatment strategies. We performed a comprehensive analysis of the immune tumor microenvironment of an ICT-sensitive tumor (melanoma, n = 44) and an ICT-resistant tumor (pancreatic cancer, n = 67). We found that a pancreatic tumor has minimal to moderate infiltration of CD3, CD4, and CD8 T cells; however, the immune infiltrates are predominantly present in the stromal area of the tumor and are excluded from tumoral area compared with melanoma, where the immune infiltrates are primarily present in the tumoral area. Metastatic pancreatic ductal adenocarcinomas (PDACs) had a lower infiltration of total T cells compared with resectable primary PDACs, suggesting that metastatic PDACs have poor immunogenicity. Further, a significantly higher number of CD68+ macrophages and VISTA+ cells (also known as V-domain immunoglobulin suppressor of T cell activation) were found in the pancreatic stromal area compared with melanoma. We identified VISTA as a potent inhibitory checkpoint that is predominantly expressed on CD68+ macrophages on PDACs. These data suggest that VISTA may be a relevant immunotherapy target for effective treatment of patients with pancreatic cancer.

What is the malignant transformation potential of oral lichen planus?

Data sources In this systematic review and meta-analysis, Medline, Scopus and Web of Science databases were searched using Medical Subject Headings (MeSH) to identify studies assessing the risk of malignant transformation in oral lichen planus (OLP).Study selection Observational studies published in English between 2003-2020 were independently assessed for inclusion by two blinded investigators.Data extraction and synthesis Data were extracted independently by two investigators followed by discussion to reach consensus. This included: study design and patient characteristics; length of follow-up; risk of bias; method of OLP diagnosis; oral squamous cell carcinoma (OSCC) risk factors; rate of malignant transformation; and individual characteristics of malignant transformation cases. Cases of malignant transformation in the included studies were only included in meta-analysis if: 1) OLP diagnosis met current diagnostic criteria; 2) OSCC developed in the same site as previously diagnosed OLP after at least six months' follow-up; 3) the patient had no history of systemic immunosuppressive therapy, head and neck malignancy, or organ transplantation. Risk of bias was assessed using the modified Newcastle-Ottawa scale, and meta-analysis was conducted to estimate overall risk of OLP malignant transformation using the DerSimonian and Laird method. Pooled univariate odds ratios (OR) for malignant transformation were calculated based on gender, smoking status, alcohol consumption, hepatitis C infection and OLP subtype.Results In total, 593 studies were identified after removal of duplicates and 33 studies were included for data extraction. The included sample comprised 12,838 patients with OLP, and 151 malignant transformation cases were reported in the included studies. The authors excluded 56 malignant transformation cases from the meta-analysis, most commonly because of the absence of pathological OLP diagnosis. Among included malignant transformation cases, the mean (SD) age was 58.1 (12.4) years, and 64% of the sample was female. Random-effects meta-analysis estimated an OLP malignant transformation rate of 0.2% (95%CI: 0.1-0.3%). Heterogeneity was low (I2 = 28.74%, p = 0.065). Malignant transformation was significantly higher among smokers (OR = 4.62, p = 0.001), alcohol consumers (OR = 3.22, p = 0.05), those with hepatitis C (OR = 3.77, p = 0.03) and atrophic or erosive OLP subtypes (OR = 2.70, p = 0.03). Gender was not associated with increased risk of malignant transformation.Conclusions The malignant transformation rate of OLP is likely to be lower than previously reported, possibly as a result of variable diagnostic criteria. Whilst encouraging, clinical vigilance remains necessary, as OLP does carry a small risk of malignant transformation. Smoking, alcohol use, hepatitis C infection and erosive or atrophic subtypes appear to have a greater rate of malignant transformation.

Do oral piercings cause problems in the mouth?

Aim This systematic review and meta-analysis aimed to synthesise the current evidence for the association of oral piercings with oral complications.Data sources Research published before January 2022 was identified from the Cochrane Library, Virtual Health Library, Web of Science, Scopus, PubMed, Embase, Google Scholar and OpenGrey databases. Experts in the field were approached via email to request access to relevant ongoing studies and unpublished results.Study design Two independent reviewers determined the eligibility of studies based on the predefined inclusion criteria. Where the outcome was unclear, a third reviewer was consulted to reach consensus. Using the Joanne Briggs institute criteria for critical appraisal, 15 studies achieved good methodological quality.Meta-analysis was conducted to determine the event rate of gingival recession and damage to teeth in participants with oral piercings and to determine odds ratios of these outcomes in participants with oral piercings compared to those without.Results In total, 54 studies published between 2000-2021 met the inclusion criteria, providing a total sample of 27,963 piercings covering various anatomical sites: tongue (39 studies), lip (29 studies) and other sites, such as oral frenula or cheek (11 studies).Meta-analysis showed that there was a 34% prevalence of dental fracture (DF) in participants with oral piercings and this was 34% for tooth wear, 33% for gingival recession (GR), 27% for non-specified dental damage and 22% for tooth chipping. A significant association was found between oral piercings and the presence of GR and DF, with a seven-fold and three-fold increased risk, respectively, when an oral piercing was present. Reporting bias was not observed and evidence certainty for these outcomes was low.Conclusions The presence of oral piercings is associated with an increased risk of gingival recession and dental fracture.

DEEP Study: Utility of the multidimensional pain inventory in persistent oro-facial pain.

BACKGROUND: Persistent oro-facial pain (POFP) is disabling, and patients' treatment outcomes are difficult to predict; psychosocial factors play a role. The West Haven-Yale Multidimensional Pain Inventory (MPI) is a self-report measure, which to our knowledge, has not been studied across primary and secondary care in heterogeneous POFP. OBJECTIVE: Assess the MPI's ability to predict clinical outcome in POFP patients across primary and secondary care settings receiving usual care. METHODS: About 146 patients receiving usual care for POFP were recruited from primary and secondary care medical and dental practices in north-east England. Participants completed the MPI (v3) and Graded Chronic Pain Scale (GCPS) at recruitment, and after 6, 12, 18 and 24 months. The Patient Health Questionnaire-4 (PHQ-4) was completed at recruitment, 12, and 24 months. 'Good' and 'poor' outcome status was assigned to participants based on their mode dichotomised GCPS score across timepoints. Logistic regression was used with overall GCPS outcome (good/poor) as the dependent variable and MPI subscale scores, demographic variables, and PHQ-4 scores as predictors. RESULTS: 110 participants had a 'good', and 36 had a 'poor' outcome. In the 'poor' outcome group, age, mean income, and life control scores were lower; deprivation, months in pain, PHQ-4, pain severity, interference, and affective distress scores were higher. In the 'good' group, MPI scores improved over time. Interference was the only consistent predictor of 'poor' outcome in the logistic regression model (OR: 1.14-1.98, p < 0.05). CONCLUSION: The MPI interference subscale may help to identify patients with POFP who are likely to have consistent pain-related disability over time; it may therefore be useful clinically to identify patients likely to need early intervention.

Evaluating aerosol and splatter following dental procedures: Addressing new challenges for oral health care and rehabilitation.

BACKGROUND: Dental procedures often produce aerosol and splatter which have the potential to transmit pathogens such as SARS-CoV-2. The existing literature is limited. OBJECTIVE(S): To develop a robust, reliable and valid methodology to evaluate distribution and persistence of dental aerosol and splatter, including the evaluation of clinical procedures. METHODS: Fluorescein was introduced into the irrigation reservoirs of a high-speed air-turbine, ultrasonic scaler and 3-in-1 spray, and procedures were performed on a mannequin in triplicate. Filter papers were placed in the immediate environment. The impact of dental suction and assistant presence were also evaluated. Samples were analysed using photographic image analysis and spectrofluorometric analysis. Descriptive statistics were calculated and Pearson's correlation for comparison of analytic methods. RESULTS: All procedures were aerosol and splatter generating. Contamination was highest closest to the source, remaining high to 1-1.5 m. Contamination was detectable at the maximum distance measured (4 m) for high-speed air-turbine with maximum relative fluorescence units (RFU) being: 46,091 at 0.5 m, 3,541 at 1.0 m and 1,695 at 4 m. There was uneven spatial distribution with highest levels of contamination opposite the operator. Very low levels of contamination (≤0.1% of original) were detected at 30 and 60 minutes post-procedure. Suction reduced contamination by 67-75% at 0.5-1.5 m. Mannequin and operator were heavily contaminated. The two analytic methods showed good correlation (r = 0.930, n = 244, P < .001). CONCLUSION: Dental procedures have potential to deposit aerosol and splatter at some distance from the source, being effectively cleared by 30 minutes in our setting.