Dendritic Cell-Based Immunotherapy in Patients With Resected Pancreatic Cancer.

PURPOSE: Immunotherapies have shown limited responses in patients with advanced pancreatic cancer. Recently, we reported that dendritic cell (DC)-based immunotherapy induced T-cell responses against pancreatic cancer antigens. The primary objective of this study was to determine the efficacy of DC-based immunotherapy to prevent recurrence of disease. METHODS: This was a single-center, open-label, single-arm, combined phase I/II trial. The primary end point was the 2-year recurrence-free survival (RFS) rate. A 2-year RFS rate of ≥60% was defined as a clinically meaningful improvement. We included patients with pancreatic cancer after resection and completion of standard-of-care (SOC) treatment without recurrent disease on cross-sectional imaging. Patients were treated with autologous DCs pulsed with an allogeneic mesothelioma tumor cell lysate, comprising antigens also expressed in pancreatic ductal adenocarcinoma. RESULTS: Thirty-eight patients were included in the analysis of the primary end point (47% male, 53% female). The median age was 62 years (IQR, 55-68). Twenty-eight patients (74%) received five DC vaccinations and completed the study protocol. Three patients (8%) received four vaccinations, and seven patients (16%) received three vaccinations. After a median follow-up of 25.5 months, 26 patients (68%) had not developed recurrence of disease. The estimated 2-year RFS was 64%. Vaccination led to the enrichment of circulating activated CD4+ T cells and the detection of treatment-induced immune responses in vitro. T-cell receptor-sequencing analyses of a resected solitary lung metastasis showed influx of vaccine-specific T cells. CONCLUSION: This study reached its primary end point of a 2-year RFS rate of ≥60% following pancreatectomy after SOC treatment and adjuvant DC-based immunotherapy in patients with pancreatic cancer. These results warrant a future randomized trial.

Monocyte infiltration is an independent positive prognostic biomarker in vulvar squamous cell carcinoma.

BACKGROUND: Vulvar squamous cell carcinoma (VSCC) arises after an HPV infection or the mutation of p53 or other driver genes and is treated by mutilating surgery and/or (chemo) radiation, with limited success and high morbidity. In-depth information on the immunological make up of VSCC is pivotal to assess whether immunotherapy may form an alternative treatment. METHODS: A total of 104 patient samples, comprising healthy vulva (n = 27) and VSCC (n = 77), were analyzed. Multispectral immunofluorescence (15 markers) was used to study both the myeloid and lymphoid immune cell composition, and this was linked to differences in transcriptomics (NanoString nCounter, 1258 genes) and in survival (Kaplan-Meier analyses). RESULTS: Healthy vulva and VSCC are both well infiltrated but with different subpopulations of lymphoid and myeloid cells. In contrast to the lymphoid cell infiltrate, the density and composition of the myeloid cell infiltrate strongly differed per VSCC molecular subtype. A relative strong infiltration with epithelial monocytes (HLADR-CD11c-CD14+CD68-CD163-CD33-) was prognostic for improved survival, independent of T cell infiltration, disease stage or molecular subtype. A strong infiltration with T cells and/or monocytes was associated with drastic superior survival: 5-year survival > 90% when either one is high, versus 40% when both are low (p < 0.001). CONCLUSION: A hot myeloid and/or lymphoid infiltrate predicts excellent survival in VSCC. Based on the response of similarly high-infiltrated other tumor types, we have started to explore the potential of neoadjuvant checkpoint blockade in VSCC.

Inhibiting the NADase CD38 improves cytomegalovirus-specific CD8+ T cell functionality and metabolism.

Cytomegalovirus (CMV) is one of the most common and relevant opportunistic pathogens in immunocompromised individuals such as kidney transplant recipients (KTRs). The exact mechanisms underlying the disability of cytotoxic T cells to provide sufficient protection against CMV in immunosuppressed individuals have not been identified yet. Here, we performed in-depth metabolic profiling of CMV-specific CD8+ T cells in immunocompromised patients and show the development of metabolic dysregulation at the transcriptional, protein, and functional level of CMV-specific CD8+ T cells in KTRs with non-controlled CMV infection. These dysregulations comprise impaired glycolysis and increased mitochondrial stress, which is associated with an intensified expression of the nicotinamide adenine dinucleotide nucleotidase (NADase) CD38. Inhibiting NADase activity of CD38 reinvigorated the metabolism and improved cytokine production of CMV-specific CD8+ T cells. These findings were corroborated in a mouse model of CMV infection under conditions of immunosuppression. Thus, dysregulated metabolic states of CD8+ T cells could be targeted by inhibiting CD38 to reverse hypo-responsiveness in individuals who fail to control chronic viral infection.

APOLLO: neo-adjuvant pembrolizumab for primary vulvar squamous cell carcinoma-a multicenter, single-arm, phase II, clinical proof-of-concept study.

BACKGROUND: Vulvar squamous cell carcinoma (VSCC) is a rare cancer for which the cornerstone of treatment is surgery with high complication rates. The unmet need is a less radical and more effective treatment for VSCC. PRIMARY OBJECTIVES: To investigate the impact of mono-immunotherapy pembrolizumab as neoadjuvant treatment for primary resectable VSCC patients. STUDY HYPOTHESIS: Some primary VSCC patients display a specific immune profile which is associated with better survival. In other tumors, this profile is associated with a better response to programmed cell death protein 1 (PD-1) checkpoint blockade which may reinvigorate tumor-specific T cells. This potentially results in a reduced tumor load and less radical surgery and/or adjuvant treatment in patients with this immune profile. TRIAL DESIGN: This is an investigator-initiated, prospective, single arm, multicenter, phase II clinical trial. INCLUSION CRITERIA: Patients with VSCC clinical stage International Federation of Gynecology and Obstetrics (FIGO) I-III (2021) eligible for primary surgery, with at least one measurable lesion of at least one dimension ≥10 mm in the largest diameter, are included in this study. MAIN EXCLUSION CRITERIA: Patients not suitable for surgery and/or previously treated with immunomodulatory agents, and/or who suffer from comorbidities that may interfere with PD-1 blockade, are excluded from the study. ENDPOINTS: The clinical efficacy of neoadjuvant pembrolizumab in VSCC is measured by an objective change in tumor size according to the Response Evaluation Criteria In Solid Tumors version 1.1 (RECIST 1.1) and documented by calipers using standardized digital photography with a reference ruler. In addition, the activation, proliferation, and migration of T cells in the tumor will be studied. The secondary endpoints are pathological complete responses at the time of surgery, feasibility, and safety. SAMPLE SIZE: 40 patients with FIGO I-III (2021) primary VSCC will be enrolled. ESTIMATED DATES FOR COMPLETING ACCRUAL AND PRESENTING RESULTS: The intervention phase started in July 2023 and will continue until July 2025. The expected completion of the entire study is July 2026. TRIAL REGISTRATION NUMBER: NCT05761132.

Autoantibody-positivity before and seroconversion during treatment with anti-PD-1 is associated with immune-related adverse events in patients with melanoma.

INTRODUCTION: Treatment with the immune checkpoint inhibitor anti-programmed cell death protein-1 (PD-1) often causes immune-related adverse events (irAEs). Since irAEs resemble autoimmune diseases, autoantibodies might play a role and could potentially be used to identify patients at risk. Therefore, we investigated the association between autoantibody-positivity and toxicity as well as clinical response in patients with melanoma treated with anti-PD-1. MATERIALS AND METHODS: This two-center, retrospective study included 143 patients with melanoma treated with anti-PD-1. Toxicities grade ≥2 and recurrences/responses were captured until 6 months after treatment initiation. Autoantibody measurements were performed at baseline and 3 months after treatment initiation, including IgM-rheumatoid factor (RF), antinuclear antibodies (ANA), extractable nuclear antigen, anti-cyclic citrullinated peptide antibodies (anti-CCP2) and anti-thyroid antibodies. RESULTS: 169 irAEs were experienced by 86/143 patients (137 grades 1-2, 32 grades 3-4), the most common being thyroiditis (n=25), dermatitis (n=24), and sicca problems (n=19). Patients with autoantibodies at baseline experienced more irAEs (p=0.001), predominantly associated with anti-thyroid antibodies and thyroid dysfunction. No association was observed between any irAE and anti-CCP2, RF or ANA. In women, baseline and on-treatment anti-thyroid antibody-positivity as well as seroconversion during treatment was associated with thyroid dysfunction. In men, this association was only observed on-treatment. The presence of autoantibodies was not associated with melanoma recurrence (p=0.776) or response (p=0.597). CONCLUSION: The presence of autoantibodies prior to anti-PD-1 therapy is associated with irAEs in patients with melanoma. Both baseline positivity and seroconversion of anti-thyroid antibodies were strongly associated with thyroid dysfunction. This association was stronger in women, with all women who were baseline positive developing thyroid dysfunction.

Immunotherapy-activated T cells recruit and skew late-stage activated M1-like macrophages that are critical for therapeutic efficacy.

Total tumor clearance through immunotherapy is associated with a fully coordinated innate and adaptive immune response, but knowledge on the exact contribution of each immune cell subset is limited. We show that therapy-induced intratumoral CD8+ T cells recruited and skewed late-stage activated M1-like macrophages, which were critical for effective tumor control in two different murine models of cancer immunotherapy. The activated CD8+ T cells summon these macrophages into the tumor and their close vicinity via CCR5 signaling. Exposure of non-polarized macrophages to activated T cell supernatant and tumor lysate recapitulates the late-stage activated and tumoricidal phenotype in vitro. The transcriptomic signature of these macrophages is also detected in a similar macrophage population present in human tumors and coincides with clinical response to immune checkpoint inhibitors. The requirement of a functional co-operation between CD8+ T cells and effector macrophages for effective immunotherapy gives warning to combinations with broad macrophage-targeting strategies.

CD4+ T cells produce IFN-I to license cDC1s for induction of cytotoxic T-cell activity in human tumors.

CD4+ T cells can "help" or "license" conventional type 1 dendritic cells (cDC1s) to induce CD8+ cytotoxic T lymphocyte (CTL) anticancer responses, as proven in mouse models. We recently identified cDC1s with a transcriptomic imprint of CD4+ T-cell help, specifically in T-cell-infiltrated human cancers, and these cells were associated with a good prognosis and response to PD-1-targeting immunotherapy. Here, we delineate the mechanism of cDC1 licensing by CD4+ T cells in humans. Activated CD4+ T cells produce IFNß via the STING pathway, which promotes MHC-I antigen (cross-)presentation by cDC1s and thereby improves their ability to induce CTL anticancer responses. In cooperation with CD40 ligand (L), IFNß also optimizes the costimulatory and other functions of cDC1s required for CTL response induction. IFN-I-producing CD4+ T cells are present in diverse T-cell-infiltrated cancers and likely deliver "help" signals to CTLs locally, according to their transcriptomic profile and colocalization with "helped/licensed" cDCs and tumor-reactive CD8+ T cells. In agreement with this scenario, the presence of IFN-I-producing CD4+ T cells in the TME is associated with overall survival and the response to PD-1 checkpoint blockade in cancer patients.

Neutralizing Antibodies Impair the Oncolytic Efficacy of Reovirus but Permit Effective Combination with T cell-Based Immunotherapies.

Reovirus type 3 Dearing (Reo), manufactured for clinical application as pelareorep, is an attractive anticancer agent under evaluation in multiple phase 2 clinical trials for the treatment of solid tumors. It elicits its anticancer efficacy by inducing both oncolysis and intratumoral T-cell influx. Because most people have been preexposed to Reo, neutralizing antibodies (NAb) are prevalent in patients with cancer and might present a barrier to effective Reo therapy. Here, we tested serum of patients with cancer and healthy controls (n = 100) and confirmed that Reo NAbs are present in >80% of individuals. To investigate the effect of NAbs on both the oncolytic and the immunostimulatory efficacy of Reo, we established an experimental mouse model with Reo preexposure. The presence of preexposure-induced NAbs reduced Reo tumor infection and prevented Reo-mediated control of tumor growth after intratumoral Reo administration. In B cell-deficient mice, the lack of NAbs provided enhanced tumor growth control after Reo monotherapy, indicating that NAbs limit the oncolytic capacity of Reo. In immunocompetent mice, intratumoral T-cell influx was not affected by the presence of preexposure-induced NAbs and consequently, combinatorial immunotherapy strategies comprising Reo and T-cell engagers or checkpoint inhibitors remained effective in these settings, also after a clinically applied regimen of multiple intravenous pelareorep administrations. Altogether, our data indicate that NAbs hamper the oncolytic efficacy of Reo, but not its immunotherapeutic capacity. Given the high prevalence of seropositivity for Reo in patients with cancer, our data strongly advocate for the application of Reo as part of T cell-based immunotherapeutic strategies.

T-cell stimulating vaccines empower CD3 bispecific antibody therapy in solid tumors.

CD3 bispecific antibody (CD3 bsAb) therapy is clinically approved for refractory hematological malignancies, but responses in solid tumors have been limited so far. One of the main hurdles in solid tumors is the lack of sufficient T-cell infiltrate. Here, we show that pre-treatment vaccination, even when composed of tumor-unrelated antigens, induces CXCR3-mediated T-cell influx in immunologically 'cold' tumor models in male mice. In the absence of CD3 bsAb, the infiltrate is confined to the tumor invasive margin, whereas subsequent CD3 bsAb administration induces infiltration of activated effector CD8 T cells into the tumor cell nests. This combination therapy installs a broadly inflamed Th1-type tumor microenvironment, resulting in effective tumor eradication. Multiple vaccination formulations, including synthetic long peptides and viruses, empower CD3 bsAb therapy. Our results imply that eliciting tumor infiltration with vaccine-induced tumor-(un)related T cells can greatly improve the efficacy of CD3 bsAbs in solid tumors.