Nivolumab + Ipilimumab as Immunotherapeutic Boost in Metastatic Urothelial Carcinoma: A Nonrandomized Clinical Trial.

Importance: Studies with nivolumab, an approved therapy for metastatic urothelial carcinoma (mUC) after platinum-based chemotherapy, demonstrate improved outcomes with added high-dose ipilimumab. Objective: To assess efficacy and safety of a tailored approach using nivolumab + ipilimumab as an immunotherapeutic boost for mUC. Design, Setting, and Participants: In this phase 2 nonrandomized trial, patients with mUC composed 2 cohorts. Cohort 1 received first-line or second-/third-line nivolumab with escalating doses of ipilimumab, and cohort 2 received second-/third-line nivolumab with high-dose ipilimumab. Recruitment spanned 26 sites in Germany and Austria from August 8, 2017, to February 18, 2021. All patients had a 70% or higher Karnofsky Performance Score and measurable disease per Response Evaluation Criteria in Solid Tumours, version 1.1. Interventions: All patients initiated 4 doses of 240-mg nivolumab (1× every 2 wk). Week 8 nonresponders received nivolumab + ipilimumab (1× every 3 wk). Cohort 1 received 2 doses of 3-mg/kg nivolumab + 1-mg/kg ipilimumab followed by 2 doses of 1-mg/kg nivolumab + 3-mg/kg ipilimumab if no response. Due to safety concerns, cohort 1 treatment was halted, and first-line cohort 2 treatment was not pursued. Cohort 2 received 2 to 4 doses of 1-mg/kg nivolumab + 3-mg/kg ipilimumab. Responders continued with nivolumab maintenance but could receive nivolumab + ipilimumab for later progression. Main Outcomes and Measures: The primary end point was objective response rate. Results: The study comprised 169 patients (118 [69.8%] men; median [range] age, 68 [37-84] years): 86 in cohort 1 (42 first-line; 44 second-/third-line) and 83 in cohort 2. The median (IQR) follow-up times were 10.4 (4.2-23.5) months (first-line cohort 1), 7.5 (3.1-23.8) months (second-/third-line cohort 1), and 6.2 (3.2-22.7) months (cohort 2). Response rates to nivolumab induction were 12/42 (29%, first-line cohort 1), 10/44 (23%, second-/third-line cohort 1), and 17/83 (20%, cohort 2). Response rates to a tailored approach were 20/42 (48% [90% CI, 34%-61%], first-line cohort 1), 12/44 (27% [90% CI, 17%-40%], second-/third-line cohort 1), and 27/83 (33% [90% CI, 23%-42%], cohort 2). Three-year overall survival rates for first-line cohort 1, second-/third-line cohort 1, and cohort 2 using the Kaplan-Meier method were 32% (95% CI, 17%-49%), 19% (95% CI, 8%-33%), and 34% (95% CI, 23%-44%), respectively. Conclusions and Relevance: In this nonrandomized trial, although first-line cohort 1 treatment improved objective response rates, considerable progression events urge caution with this as a first-line therapy. Second-/third-line cohort 1 treatment did not improve response rates compared with nivolumab monotherapy. However, added high-dose ipilimumab may improve tumor response and survival in patients with mUC. Trial Registration: ClinicalTrials.gov Identifier: NCT03219775.

Correlation of microscopic tumor extension with tumor microenvironment in esophageal cancer patients.

OBJECTIVE: In the era of image-guided adaptive radiotherapy, definition of the clinical target volume (CTV) is a challenge in various solid tumors, including esophageal cancer (EC). Many tumor microenvironmental factors, e.g., tumor cell proliferation or cancer stem cells, are hypothesized to be involved in microscopic tumor extension (MTE). Therefore, this study assessed the expression of FAK, ILK, CD44, HIF-1α, and Ki67 in EC patients after neoadjuvant radiochemotherapy followed by tumor resection (NRCHT+R) and correlated these markers with the MTE. METHODS: Formalin-fixed paraffin-embedded tumor resection specimens of ten EC patients were analyzed using multiplex immunofluorescence staining. Since gold fiducial markers had been endoscopically implanted at the proximal and distal tumor borders prior to NRCHT+R, correlation of the markers with the MTE was feasible. RESULTS: In tumor resection specimens of EC patients, the overall percentages of FAK+, CD44+, HIF-1α+, and Ki67+ cells were higher in tumor nests than in the tumor stroma, with the outcome for Ki67+ cells reaching statistical significance (p < 0.001). Conversely, expression of ILK+ cells was higher in tumor stroma, albeit not statistically significantly. In three patients, MTE beyond the fiducial markers was found, reaching up to 31 mm. CONCLUSION: Our findings indicate that the overall expression of FAK, HIF-1α, Ki67, and CD44 was higher in tumor nests, whereas that of ILK was higher in tumor stroma. Differences in the TME between patients with residual tumor cells in the original CTV compared to those without were not found. Thus, there is insufficient evidence that the TME influences the required CTV margin on an individual patient basis. TRIAL REGISTRATION NUMBER AND DATE: BO-EK-148042017 and BO-EK-177042022 on 20.06.2022, DRKS00011886, https://drks.de/search/de/trial/DRKS00011886 .

Neoadjuvant chemotherapy is associated with suppression of the B cell-centered immune landscape in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is typically diagnosed at advanced stages and associated with early distant metastasis and poor survival. Besides clinical factors, the tumor microenvironment (TME) emerged as a crucial determinant of patient survival and therapy response in many tumors, including PDAC. Thus, the presence of tumor-infiltrating lymphocytes and the formation of tertiary lymphoid structures (TLS) is associated with longer survival in PDAC. Although neoadjuvant therapy (NeoTx) has improved the management of locally advanced tumors, detailed insight into its effect on various TME components is limited. While a remodeling towards a proinflammatory state was reported for PDAC-infiltrating T cells, the effect of NeoTx on B cell subsets, including plasma cells, and TLS formation is widely unclear. We thus investigated the frequency, composition, and spatial distribution of PDAC-infiltrating B cells in primary resected (PR) versus neoadjuvant-treated patients using a novel multiplex immunohistochemistry panel. The NeoTx group displayed significantly lower frequencies of pan B cells, GC B cells, plasmablasts, and plasma cells, accompanied by a reduced abundance of TLS. This finding was supported by bulk RNA-sequencing analysis of an independent fresh frozen tissue cohort, which revealed that major B cell pathways were downregulated in the NeoTx group. We further observed that plasma cells frequently formed aggregates that localized close to TLS and that TLS+ patients displayed significantly higher plasma cell frequencies compared to TLS- patients in the PR group. Additionally, high densities of CD20+ intratumoral B cells were significantly associated with longer overall survival in the PR group. While CD20+ B cells held no prognostic value for NeoTx patients, an increased frequency of proliferating CD20+Ki67+ B cells emerged as an independent prognostic factor for longer survival in the NeoTx group. These results indicate that NeoTx differentially affects PDAC-infiltrating immune cells and may have detrimental effects on the existing B cell landscape and the formation of TLS. Gaining further insight into the underlying molecular mechanisms is crucial to overcome the intrinsic immunotherapy resistance of PDAC and develop novel strategies to improve the long-term outcome of PDAC patients.

Tumor-targeted therapy with BRAF-inhibitor recruits activated dendritic cells to promote tumor immunity in melanoma.

BACKGROUND: Tumor-targeted therapy causes impressive tumor regression, but the emergence of resistance limits long-term survival benefits in patients. Little information is available on the role of the myeloid cell network, especially dendritic cells (DC) during tumor-targeted therapy. METHODS: Here, we investigated therapy-mediated immunological alterations in the tumor microenvironment (TME) and tumor-draining lymph nodes (LN) in the D4M.3A preclinical melanoma mouse model (harboring the V-Raf murine sarcoma viral oncogene homolog B (BRAF)V600E mutation) by using high-dimensional multicolor flow cytometry in combination with multiplex immunohistochemistry. This was complemented with RNA sequencing and cytokine quantification to characterize the immune status of the tumors. The importance of T cells during tumor-targeted therapy was investigated by depleting CD4+ or CD8+ T cells in tumor-bearing mice. Tumor antigen-specific T-cell responses were characterized by performing in vivo T-cell proliferation assays and the contribution of conventional type 1 DC (cDC1) to T-cell immunity during tumor-targeted therapy was assessed using Batf3-/- mice lacking cDC1. RESULTS: Our findings reveal that BRAF-inhibitor therapy increased tumor immunogenicity, reflected by an upregulation of genes associated with immune activation. The T cell-inflamed TME contained higher numbers of activated cDC1 and cDC2 but also inflammatory CCR2-expressing monocytes. At the same time, tumor-targeted therapy enhanced the frequency of migratory, activated DC subsets in tumor-draining LN. Even more, we identified a cDC2 population expressing the Fc gamma receptor I (FcγRI)/CD64 in tumors and LN that displayed high levels of CD40 and CCR7 indicating involvement in T cell-mediated tumor immunity. The importance of cDC2 is underlined by just a partial loss of therapy response in a cDC1-deficient mouse model. Both CD4+ and CD8+ T cells were essential for therapy response as their respective depletion impaired therapy success. On resistance development, the tumors reverted to an immunologically inert state with a loss of DC and inflammatory monocytes together with the accumulation of regulatory T cells. Moreover, tumor antigen-specific CD8+ T cells were compromised in proliferation and interferon-γ-production. CONCLUSION: Our results give novel insights into the remodeling of the myeloid landscape by tumor-targeted therapy. We demonstrate that the transient immunogenic tumor milieu contains more activated DC. This knowledge has important implications for the development of future combinatorial therapies.

Clonal hematopoiesis and its impact on the aging osteo-hematopoietic niche.

Clonal hematopoiesis (CH) defines a premalignant state predominantly found in older persons that increases the risk of developing hematologic malignancies and age-related inflammatory diseases. However, the risk for malignant transformation or non-malignant disorders is variable and difficult to predict, and defining the clinical relevance of specific candidate driver mutations in individual carriers has proved to be challenging. In addition to the cell-intrinsic mechanisms, mutant cells rely on and alter cell-extrinsic factors from the bone marrow (BM) niche, which complicates the prediction of a mutant cell's fate in a shifting pre-malignant microenvironment. Therefore, identifying the insidious and potentially broad impact of driver mutations on supportive niches and immune function in CH aims to understand the subtle differences that enable driver mutations to yield different clinical outcomes. Here, we review the changes in the aging BM niche and the emerging evidence supporting the concept that CH can progressively alter components of the local BM microenvironment. These alterations may have profound implications for the functionality of the osteo-hematopoietic niche and overall bone health, consequently fostering a conducive environment for the continued development and progression of CH. We also provide an overview of the latest technology developments to study the spatiotemporal dependencies in the CH BM niche, ideally in the context of longitudinal studies following CH over time. Finally, we discuss aspects of CH carrier management in clinical practice, based on work from our group and others.

CD38 promotes hematopoietic stem cell dormancy.

A subpopulation of deeply quiescent, so-called dormant hematopoietic stem cells (dHSCs) resides at the top of the hematopoietic hierarchy and serves as a reserve pool for HSCs. The state of dormancy protects the HSC pool from exhaustion throughout life; however, excessive dormancy may prevent an efficient response to hematological stresses. Despite the significance of dHSCs, the mechanisms maintaining their dormancy remain elusive. Here, we identify CD38 as a novel and broadly applicable surface marker for the enrichment of murine dHSCs. We demonstrate that cyclic adenosine diphosphate ribose (cADPR), the product of CD38 cyclase activity, regulates the expression of the transcription factor c-Fos by increasing the release of Ca2+ from the endoplasmic reticulum (ER). Subsequently, we uncover that c-Fos induces the expression of the cell cycle inhibitor p57Kip2 to drive HSC dormancy. Moreover, we found that CD38 ecto-enzymatic activity at the neighboring CD38-positive cells can promote human HSC quiescence. Together, CD38/cADPR/Ca2+/c-Fos/p57Kip2 axis maintains HSC dormancy. Pharmacological manipulations of this pathway can provide new strategies to improve the success of stem cell transplantation and blood regeneration after injury or disease.

Bone marrow-derived mesenchymal stromal cells obstruct AML-targeting CD8+ clonal effector and CAR T-cell function while promoting a senescence-associated phenotype.

Bone marrow mesenchymal stromal cells (MSCs) have been described as potent regulators of T-cell function, though whether they could impede the effectiveness of immunotherapy against acute myeloid leukemia (AML) is still under investigation. We examine whether they could interfere with the activity of leukemia-specific clonal cytotoxic T-lymphocytes (CTLs) and chimeric antigen receptor (CAR) T cells, as well as whether the immunomodulatory properties of MSCs could be associated with the induction of T-cell senescence. Co-cultures of leukemia-associated Wilm's tumor protein 1 (WT1) and tyrosine-protein kinase transmembrane receptor 1 (ROR1)-reactive CTLs and of CD123-redirected switchable CAR T cells were prepared in the presence of MSCs and assessed for cytotoxic potential, cytokine secretion, and expansion. T-cell senescence within functional memory sub-compartments was investigated for the senescence-associated phenotype CD28-CD57+ using unmodified peripheral blood mononuclear cells. We describe inhibition of expansion of AML-redirected switchable CAR T cells by MSCs via indoleamine 2,3-dioxygenase 1 (IDO-1) activity, as well as reduction of interferon gamma (IFNγ) and interleukin-2 (IL-2) release. In addition, MSCs interfered with the secretory potential of leukemia-associated WT1- and ROR1-targeting CTL clones, inhibiting the release of IFNγ, tumor necrosis factor alpha, and IL-2. Abrogated T cells were shown to retain their cytolytic activity. Moreover, we demonstrate induction of a CD28loCD27loCD57+KLRG1+ senescent T-cell phenotype by MSCs. In summary, we show that MSCs are potent modulators of anti-leukemic T cells, and targeting their modes of action would likely be beneficial in a combinatorial approach with AML-directed immunotherapy.

BRAF and MEK inhibitor combinations induce potent molecular and immunological effects in NRAS-mutant melanoma cells: Insights into mode of action and resistance mechanisms.

About 25% of melanoma harbor activating NRAS mutations, which are associated with aggressive disease therefore requiring a rapid antitumor intervention. However, no efficient targeted therapy options are currently available for patients with NRAS-mutant melanoma. MEK inhibitors (MEKi) appear to display a moderate antitumor activity and also immunological effects in NRAS-mutant melanoma, providing an ideal backbone for combination treatments. In our study, the MEKi binimetinib, cobimetinib and trametinib combined with the BRAF inhibitors (BRAFi) encorafenib, vemurafenib and dabrafenib were investigated for their ability to inhibit proliferation, induce apoptosis and alter the expression of immune modulatory molecules in sensitive NRAS-mutant melanoma cells using two- and three-dimensional cell culture models as well as RNA sequencing analyses. Furthermore, NRAS-mutant melanoma cells resistant to the three BRAFi/MEKi combinations were established to characterize the mechanisms contributing to their resistance. All BRAFi induced a stress response in the sensitive NRAS-mutant melanoma cells thereby significantly enhancing the antiproliferative and proapoptotic activity of the MEKi analyzed. Furthermore, BRAFi/MEKi combinations upregulated immune relevant molecules, such as ICOS-L, components of antigen-presenting machinery and the "don't eat me signal" molecule CD47 in the melanoma cells. The BRAFi/MEKi-resistant, NRAS-mutant melanoma cells counteracted the molecular and immunological effects of BRAFi/MEKi by upregulating downstream mitogen-activated protein kinase pathway molecules, inhibiting apoptosis and promoting immune escape mechanisms. Together, our study reveals potent molecular and immunological effects of BRAFi/MEKi in sensitive NRAS-mutant melanoma cells that may be exploited in new combinational treatment strategies for patients with NRAS-mutant melanoma.

Immunotheranostic target modules for imaging and navigation of UniCAR T-cells to strike FAP-expressing cells and the tumor microenvironment.

BACKGROUND: Chimeric antigen receptor (CAR) T-cells are a promising approach in cancer immunotherapy, particularly for treating hematologic malignancies. Yet, their effectiveness is limited when tackling solid tumors, where immune cell infiltration and immunosuppressive tumor microenvironments (TME) are major hurdles. Fibroblast activation protein (FAP) is highly expressed on cancer-associated fibroblasts (CAFs) and various tumor cells, playing an important role in tumor growth and immunosuppression. Aiming to modulate the TME with increased clinical safety and effectiveness, we developed novel small and size-extended immunotheranostic UniCAR target modules (TMs) targeting FAP. METHODS: The specific binding and functionality of the αFAP-scFv TM and the size-extended αFAP-IgG4 TM were assessed using 2D and 3D in vitro models as well as in vivo. Their specific tumor accumulation and diagnostic potential were evaluated using PET studies after functionalization with a chelator and suitable radionuclide. RESULTS: The αFAP-scFv and -IgG4 TMs effectively and specifically redirected UniCAR T-cells using 2D, 3D, and in vivo models. Moreover, a remarkably high and specific accumulation of radiolabeled FAP-targeting TMs at the tumor site of xenograft mouse models was observed. CONCLUSIONS: These findings demonstrate that the novel αFAP TMs are promising immunotheranostic tools to foster cancer imaging and treatment, paving the way for a more convenient, individualized, and safer treatment of cancer patients.

Immune Surveillance of Acute Myeloid Leukemia Is Mediated by HLA-Presented Antigens on Leukemia Progenitor Cells.

Therapy-resistant leukemia stem and progenitor cells (LSC) are a main cause of acute myeloid leukemia (AML) relapse. LSC-targeting therapies may thus improve outcome of patients with AML. Here we demonstrate that LSCs present HLA-restricted antigens that induce T-cell responses allowing for immune surveillance of AML. Using a mass spectrometry-based immunopeptidomics approach, we characterized the antigenic landscape of patient LSCs and identified AML- and AML/LSC-associated HLA-presented antigens absent from normal tissues comprising nonmutated peptides, cryptic neoepitopes, and neoepitopes of common AML driver mutations of NPM1 and IDH2. Functional relevance of shared AML/LSC antigens is illustrated by presence of their cognizant memory T cells in patients. Antigen-specific T-cell recognition and HLA class II immunopeptidome diversity correlated with clinical outcome. Together, these antigens shared among AML and LSCs represent prime targets for T cell-based therapies with potential of eliminating residual LSCs in patients with AML. SIGNIFICANCE: The elimination of therapy-resistant leukemia stem and progenitor cells (LSC) remains a major challenge in the treatment of AML. This study identifies and functionally validates LSC-associated HLA class I and HLA class II-presented antigens, paving the way to the development of LSC-directed T cell-based immunotherapeutic approaches for patients with AML. See related commentary by Ritz, p. 430 . This article is featured in Selected Articles from This Issue, p. 419.

Tailored immunotherapy approach with nivolumab with or without nivolumab plus ipilimumab as immunotherapeutic boost in patients with metastatic renal cell carcinoma (TITAN-RCC): a multicentre, single-arm, phase 2 trial.

BACKGROUND: Nivolumab plus ipilimumab is approved as first-line regimen for intermediate-risk or poor-risk metastatic renal cell carcinoma, and nivolumab monotherapy as second-line therapy for all risk groups. We aimed to examine the efficacy and safety of nivolumab monotherapy and nivolumab plus ipilimumab combination as an immunotherapeutic boost after no response to nivolumab monotherapy in patients with intermediate-risk and poor-risk clear-cell metastatic renal cell carcinoma. METHODS: TITAN-RCC is a multicentre, single-arm, phase 2 trial, done at 28 hospitals and cancer centres across Europe (Austria, Belgium, Czech Republic, France, Germany, Italy, Spain, and the UK). Adults (aged ≥18 years) with histologically confirmed intermediate-risk or poor-risk clear-cell metastatic renal cell carcinoma who were formerly untreated (first-line population) or pretreated with one previous systemic therapy (anti-angiogenic or temsirolimus; second-line population) were eligible. Patients had to have a Karnofsky Performance Status score of at least 70 and measurable disease per Response Evaluation Criteria in Solid Tumours (version 1.1). Patients started with intravenous nivolumab 240 mg once every 2 weeks. On early progressive disease (week 8) or non-response at week 16, patients received two or four doses of intravenous nivolumab (3 mg/kg) and ipilimumab (1 mg/kg) boosts (once every 3 weeks), whereas responders continued with intravenous nivolumab (240 mg, once every 2 weeks), but could receive two to four boost doses of nivolumab plus ipilimumab for subsequent progressive disease. The primary endpoint was confirmed investigator-assessed objective response rate in the full analysis set, which included all patients who received at least one dose of study medication; safety was also assessed in this population. An objective response rate of more than 25% was required to reject the null hypothesis and show improvement, on the basis of results from the pivotal phase 3 CheckMate-025 trial. This study is registered with ClinicalTrials.gov, NCT02917772, and is complete. FINDINGS: Between Oct 28, 2016, and Nov 30, 2018, 207 patients were enrolled and all received nivolumab induction (109 patients in the first-line group; 98 patients in the second-line group). 60 (29%) of 207 patients were female and 147 (71%) were male. 147 (71%) of 207 patients had intermediate-risk metastatic renal cell carcinoma and 51 (25%) had poor-risk disease. After median follow-up of 27·6 months (IQR 10·5-34·8), 39 (36%, 90% CI 28-44; p=0·0080) of 109 patients in the first-line group and 31 (32%, 24-40; p=0·083) of 98 patients in the second-line group had a confirmed objective response for nivolumab with and without nivolumab plus ipilimumab. Confirmed response to nivolumab at week 8 or 16 was observed in 31 (28%) of 109 patients in the first-line group and 18 (18%) of 98 patients in the second-line group. The most frequent grade 3-4 treatment-related adverse events (reported in ≥5% of patients) were increased lipase (15 [7%] of 207 patients), colitis (13 [6%]), and diarrhoea (13 [6%]). Three deaths were reported that were deemed to be treatment-related: one due to possible ischaemic stroke, one due to respiratory failure, and one due to pneumonia. INTERPRETATION: In treatment-naive patients, nivolumab induction with or without nivolumab plus ipilimumab boosts significantly improved the objective response rate compared with that reported for nivolumab monotherapy in the CheckMate-025 trial. However, overall efficacy seemed inferior when compared with approved upfront nivolumab plus ipilimumab. For second-line treatment, nivolumab plus ipilimumab could be a rescue strategy on progression with approved nivolumab monotherapy. FUNDING: Bristol Myers Squibb.

Prognostic impact of the post-treatment T cell composition and spatial organization in soft tissue sarcoma patients treated with neoadjuvant hyperthermic radio(chemo)therapy.

Soft tissue sarcomas (STS) form a heterogeneous group of tumors sharing a mesenchymal origin. Despite good local control of the disease, the occurrence of distant metastases often limits survival of STS patients with localized, high-risk tumors of the extremities. Accumulating evidence suggests a central role for the tumor immune microenvironment in determining the clinical outcome and response to therapy. Thus, it has been reported that STS patients with a high immune signature and especially presence of B cells and tertiary lymphoid structures display improved overall survival and response to checkpoint inhibitor treatment. Here, we explored the effect of curative multimodal therapy on the T cell landscape of STS using multiplex immunohistochemistry. We analyzed the phenotype, frequency, and spatial distribution of STS-infiltrating CD8+ T cells by staining for CD8, 4-1BB, Granzyme B, Ki67, PD-1, and LAG-3 as well as CD3+ T helper cells using a panel consisting of CD3, T-bet, GATA3, RORγT, FoxP3, and Ki67. All patients received neoadjuvant radiotherapy plus locoregional hyperthermia with or without chemotherapy. While the treatment-naïve biopsy sample allows an analysis of baseline T cell infiltration levels, both intra- and peritumoral areas of the matched resected tissue were analyzed to assess composition and spatial distribution of the T cell compartment and its therapeutic modulation. Generally, post-treatment tissues displayed lower frequencies of CD3+ and CD8+ T cells. Association with clinical data revealed that higher post-treatment frequencies of peritumoral and intratumoral CD3+ T cells and intratumoral PD-1+ CD8+ T cells were significantly associated with improved disease-free survival (DFS), while these densities had no prognostic significance in the biopsy. Upon spatial analysis, a high ratio of intratumoral to peritumoral CD8+ T cells emerged as an independent prognostic marker for longer DFS. These results indicate that the STS T cell landscape is altered by multimodal therapy and may influence the clinical outcome of patients. An enhanced understanding of the STS immune architecture and its modulation by neoadjuvant therapy may pave the way towards novel treatment modalities and improve the long-term clinical outcome of STS patients.

VISTA Ligation Reduces Antitumor T-Cell Activity in Pancreatic Cancer.

Immunotherapy has shown promising results in multiple solid tumors and hematological malignancies. However, pancreatic ductal adenocarcinoma (PDAC) has been largely refractory to current clinical immunotherapies. The V-domain Ig suppressor of T-cell activation (VISTA) inhibits T-cell effector function and maintains peripheral tolerance. Here, we determine VISTA expression in nontumorous pancreatic (n = 5) and PDAC tissue using immunohistochemistry (n = 76) and multiplex immunofluorescence staining (n = 67). Additionally, VISTA expression on tumor-infiltrating immune cells and matched blood samples (n = 13) was measured with multicolor flow cytometry. Further, the effect of recombinant VISTA on T-cell activation was investigated in vitro, and VISTA blockade was tested in an orthotopic PDAC mouse model in vivo. PDAC showed significantly higher VISTA expression compared to that of a nontumorous pancreas. Patients with a high density of VISTA-expressing tumor cells had reduced overall survival. The VISTA expression of CD4+ and CD8+ T cells was increased after stimulation and particularly after a coculture with tumor cells. We detected a higher level of proinflammatory cytokine (TNFα and IFNγ) expression by CD4+ and CD8+ T cells, which was reversed with the addition of recombinant VISTA. A VISTA blockade reduced tumor weights in vivo. The VISTA expression of tumor cells has clinical relevance, and its blockade may be a promising immunotherapeutic strategy for PDAC.

Tailored immunotherapy approach with nivolumab with or without ipilimumab in patients with advanced transitional cell carcinoma after platinum-based chemotherapy (TITAN-TCC): a multicentre, single-arm, phase 2 trial.

BACKGROUND: Nivolumab is used after platinum-based chemotherapy in patients with metastatic urothelial carcinoma. Studies suggest improved outcomes for dual checkpoint inhibition with high ipilimumab doses. We aimed to examine the safety and activity of nivolumab induction and high-dose ipilimumab as an immunotherapeutic boost as a second-line treatment for patients with metastatic urothelial carcinoma. METHODS: TITAN-TCC is a multicentre, single-arm, phase 2 trial done at 19 hospitals and cancer centres in Germany and Austria. Adults aged 18 years or older with histologically confirmed metastatic or surgically unresectable urothelial cancer of the bladder, urethra, ureter, or renal pelvis were eligible. Patients had to have progression during or after first-line platinum-based chemotherapy and up to one more second-line or third-line treatment, a Karnofsky Performance Score of 70 or higher, and measurable disease as per Response Evaluation Criteria in Solid Tumors version 1.1. After four doses of intravenous nivolumab 240 mg induction monotherapy every 2 weeks, patients with a partial or complete response at week 8 continued maintenance nivolumab, whereas those with stable or progressive disease (non-responders) at week 8 received a boost of two or four doses of intravenous nivolumab 1 mg/kg plus ipilimumab 3 mg/kg every 3 weeks. Patients who subsequently had progressive disease during nivolumab maintenance also received a boost, using this schedule. The primary endpoint was the confirmed investigator-assessed objective response rate in the intention-to-treat population and had to exceed 20% for the null hypothesis to be rejected (based on the objective response rate with nivolumab monotherapy in the CheckMate-275 phase 2 trial). This study is registered with ClinicalTrials.gov, NCT03219775, and is ongoing. FINDINGS: Between April 8, 2019, and Feb 15, 2021, 83 patients with metastatic urothelial carcinoma were enrolled and all received nivolumab induction treatment (intention-to-treat population). The median age of enrolled patients was 68 years (IQR 61-76), and 57 (69%) were male and 26 (31%) were female. 50 (60%) patients received at least one boost dose. A confirmed investigator-assessed objective response was recorded in 27 (33%) of 83 patients in the intention-to-treat population, including six (7%) patients who had a complete response. This objective response rate was significantly higher than the prespecified threshold of 20% or less (33% [90% CI 24-42]; p=0·0049). The most common grade 3-4 treatment-related adverse events were immune-mediated enterocolitis (nine [11%] patients) and diarrhoea (five [6%] patients). Two (2%) treatment-related deaths were reported, both due to immune-mediated enterocolitis. INTERPRETATION: Treatment with nivolumab and nivolumab plus ipilimumab boosts in early non-responders and patients who progress late significantly improved objective response rate after previous platinum-based chemotherapy compared with the rate reported with nivolumab in the CheckMate-275 trial. Our study provides evidence for the added value of high-dose ipilimumab 3 mg/kg and suggests a potential role for the combination as a rescue strategy in platinum-pretreated patients with metastatic urothelial carcinoma. FUNDING: Bristol Myers Squibb.

Palbociclib impairs the proliferative capacity of activated T cells while retaining their cytotoxic efficacy.

The cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor palbociclib is an emerging cancer therapeutic that just recently gained Food and Drug Administration approval for treatment of estrogen receptor (ER)-positive, human epidermal growth factor receptor (Her)2-negative breast cancer in combination with the ER degrader fulvestrant. However, CDK4/6 inhibitors are not cancer-specific and may affect also other proliferating cells. Given the importance of T cells in antitumor defense, we studied the influence of palbociclib/fulvestrant on human CD3+ T cells and novel emerging T cell-based cancer immunotherapies. Palbociclib considerably inhibited the proliferation of activated T cells by mediating G0/G1 cell cycle arrest. However, after stopping the drug supply this suppression was fully reversible. In light of combination approaches, we further investigated the effect of palbociclib/fulvestrant on T cell-based immunotherapies by using a CD3-PSCA bispecific antibody or universal chimeric antigen receptor (UniCAR) T cells. Thereby, we observed that palbociclib clearly impaired T cell expansion. This effect resulted in a lower total concentration of interferon-γ and tumor necrosis factor, while palbociclib did not inhibit the average cytokine release per cell. In addition, the cytotoxic potential of the redirected T cells was unaffected by palbociclib and fulvestrant. Overall, these novel findings may have implications for the design of treatment modalities combining CDK4/6 inhibition and T cell-based cancer immunotherapeutic strategies.

Guidelines for visualization and analysis of DC in tissues using multiparameter fluorescence microscopy imaging methods.

This article is part of the Dendritic Cell Guidelines article series, which provides a collection of state-of-the-art protocols for the preparation, phenotype analysis by flow cytometry, generation, fluorescence microscopy, and functional characterization of mouse and human dendritic cells (DC) from lymphoid organs and various non-lymphoid tissues. Here, we provide detailed procedures for a variety of multiparameter fluorescence microscopy imaging methods to explore the spatial organization of DC in tissues and to dissect how DC migrate, communicate, and mediate their multiple functional roles in immunity in a variety of tissue settings. The protocols presented here entail approaches to study DC dynamics and T cell cross-talk by intravital microscopy, large-scale visualization, identification, and quantitative analysis of DC subsets and their functions by multiparameter fluorescence microscopy of fixed tissue sections, and an approach to study DC interactions with tissue cells in a 3D cell culture model. While all protocols were written by experienced scientists who routinely use them in their work, this article was also peer-reviewed by leading experts and approved by all co-authors, making it an essential resource for basic and clinical DC immunologists.

Deficiency for SAMHD1 activates MDA5 in a cGAS/STING-dependent manner.

Defects in nucleic acid metabolizing enzymes can lead to spontaneous but selective activation of either cGAS/STING or RIG-like receptor (RLR) signaling, causing type I interferon-driven inflammatory diseases. In these pathophysiological conditions, activation of the DNA sensor cGAS and IFN production are linked to spontaneous DNA damage. Physiological, or tonic, IFN signaling on the other hand is essential to functionally prime nucleic acid sensing pathways. Here, we show that low-level chronic DNA damage in mice lacking the Aicardi-Goutières syndrome gene SAMHD1 reduced tumor-free survival when crossed to a p53-deficient, but not to a DNA mismatch repair-deficient background. Increased DNA damage did not result in higher levels of type I interferon. Instead, we found that the chronic interferon response in SAMHD1-deficient mice was driven by the MDA5/MAVS pathway but required functional priming through the cGAS/STING pathway. Our work positions cGAS/STING upstream of tonic IFN signaling in Samhd1-deficient mice and highlights an important role of the pathway in physiological and pathophysiological innate immune priming.

Neoadjuvant chemotherapy drives intratumoral T cells toward a proinflammatory profile in pancreatic cancer.

BACKGROUNDPancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis. At diagnosis, only 20% of patients with PDAC are eligible for primary resection. Neoadjuvant chemotherapy can enable surgical resection in 30%-40% of patients with locally advanced and borderline resectable PDAC. The effects of neoadjuvant chemotherapy on the cytokine production of tumor-infiltrating T cells are unknown in PDAC.METHODSWe performed multiplex immunofluorescence to investigate T cell infiltration in 91 patients with PDAC. Using flow cytometry, we analyzed tumor and matched blood samples from 71 patients with PDAC and determined the frequencies of T cell subsets and their cytokine profiles. Both cohorts included patients who underwent primary resection and patients who received neoadjuvant chemotherapy followed by surgical resection.RESULTSIn human PDAC, T cells were particularly enriched within the tumor stroma. Neoadjuvant chemotherapy markedly enhanced T cell density within the ductal area of the tumor. Whereas infiltration of cytotoxic CD8+ T cells was unaffected by neoadjuvant chemotherapy, the frequency of conventional CD4+ T cells was increased, and the proportion of Tregs was reduced in the pancreatic tumor microenvironment after neoadjuvant treatment. Moreover, neoadjuvant chemotherapy increased the production of proinflammatory cytokines by tumor-infiltrating T cells, with enhanced TNF-α and IL-2 and reduced IL-4 and IL-10 expression.CONCLUSIONNeoadjuvant chemotherapy drives intratumoral T cells toward a proinflammatory profile. Combinational treatment strategies incorporating immunotherapy in neoadjuvant regimens may unleash more effective antitumor responses and improve prognosis of pancreatic cancer.FUNDINGThis work was supported by the Jung Foundation for Science and Research, the Monika Kutzner Foundation, the German Research Foundation (SE2980/5-1), the German Cancer Consortium, and the Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden.

Repeated lipoprotein apheresis and immune response: Effects on different immune cell populations.

BACKGROUND: Atherosclerosis is considered a chronic inflammation of arterial vessels with the involvement of several immune cells causing severe cardiovascular diseases. Lipoprotein apheresis (LA) improves cardiovascular conditions of patients with severely disturbed lipid metabolism. In this context, little is known about the impact of LA on various immune cell populations, especially over time. METHODS: Immune cells of 18 LA-naïve patients starting weekly LA treatment were analyzed before and after four apheresis cycles over the course of 24 weeks by flow cytometry. RESULTS AND CONCLUSIONS: An acute lowering effect of LA on T cell and natural killer (NK) cell subpopulations expressing CD69 was observed. The non-classical and intermediate monocyte subsets as well as HLA-DR+ 6-sulfo LacNAc+ monocytes were significantly reduced during the apheresis procedure. We conclude that LA has the capacity to alter various immune cell subsets. However, LA has mainly short-term effects than long-term consequences on proportions of immune cells.