A gut microbial signature for combination immune checkpoint blockade across cancer types.

Immune checkpoint blockade (ICB) targeting programmed cell death protein 1 (PD-1) and cytotoxic T lymphocyte protein 4 (CTLA-4) can induce remarkable, yet unpredictable, responses across a variety of cancers. Studies suggest that there is a relationship between a cancer patient's gut microbiota composition and clinical response to ICB; however, defining microbiome-based biomarkers that generalize across cohorts has been challenging. This may relate to previous efforts quantifying microbiota to species (or higher taxonomic rank) abundances, whereas microbial functions are often strain specific. Here, we performed deep shotgun metagenomic sequencing of baseline fecal samples from a unique, richly annotated phase 2 trial cohort of patients with diverse rare cancers treated with combination ICB (n = 106 discovery cohort). We demonstrate that strain-resolved microbial abundances improve machine learning predictions of ICB response and 12-month progression-free survival relative to models built using species-rank quantifications or comprehensive pretreatment clinical factors. Through a meta-analysis of gut metagenomes from a further six comparable studies (n = 364 validation cohort), we found cross-cancer (and cross-country) validity of strain-response signatures, but only when the training and test cohorts used concordant ICB regimens (anti-PD-1 monotherapy or combination anti-PD-1 plus anti-CTLA-4). This suggests that future development of gut microbiome diagnostics or therapeutics should be tailored according to ICB treatment regimen rather than according to cancer type.

Chemotherapy after immune checkpoint inhibitor failure in metastatic melanoma: a retrospective multicentre analysis.

INTRODUCTION: Despite remarkably improved outcomes with immune checkpoint inhibition, many patients with metastatic melanoma will eventually require further therapy. Chemotherapy has limited activity when used first-line but can alter the tumour microenvironment and does improve efficacy when used in combination with immunotherapy in lung cancer. Whether chemotherapy after checkpoint inhibitor failure has relevant activity in patients with metastatic melanoma is unknown. METHODS: Patients with metastatic melanoma treated with chemotherapy after progression on immunotherapy with checkpoint inhibitors were identified retrospectively from 24 melanoma centres. Objective response rate (ORR), progression-free survival (PFS), overall survival (OS) and safety were examined. RESULTS: In total, 463 patients were treated between 2007 and 2017. Fifty-six per cent had received PD-1-based therapy before chemotherapy. Chemotherapy regimens included carboplatin + paclitaxel (32%), dacarbazine (25%), temozolomide (15%), taxanes (9%, nab-paclitaxel 4%), fotemustine (6%) and others (13%). Median duration of therapy was 7.9 weeks (0-108). Responses included 0.4% complete response (CR), 12% partial response (PR), 21% stable disease (SD) and 67% progressive disease (PD). Median PFS was 2.6 months (2.2, 3.0), and median PFS in responders was 8.7 months (6.3, 16.3), respectively. Twelve-month PFS was 12% (95% CI 2-15%). In patients who had received anti-PD-1 before chemotherapy, the ORR was 11%, and median PFS was 2.5 months (2.1, 2.8). The highest activity was achieved with single-agent taxanes (N = 40), with ORR 25% and median PFS 3.9 months (2.1, 6.2). Median OS from chemotherapy start was 7.1 months (6.5, 8.0). Subsequent treatment with checkpoint inhibitors achieved a response rate of 16% with a median PFS of 19.1 months (2.0-43.1 months). No unexpected toxicities were observed. CONCLUSION: Chemotherapy has a low response rate and short PFS in patients with metastatic melanoma who have failed checkpoint inhibitor therapy, although activity varied between regimens. Chemotherapy has a limited role in the management of metastatic melanoma.

Combination immunotherapy with nivolumab and ipilimumab in patients with rare gynecological malignancies: results of the CA209-538 clinical trial.

BACKGROUND: Patients with rare cancers represent 55% of all gynecological malignancies and have poor survival outcomes due to limited treatment options. Combination immunotherapy with the anti-programmed cell death protein 1 (anti-PD-1) antibody nivolumab and the anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA-4) antibody ipilimumab has demonstrated significant clinical efficacy across a range of common malignancies, justifying evaluation of this combination in rare gynecological cancers. METHODS: This multicenter phase II study enrolled 43 patients with advanced rare gynecological cancers. Patients received induction treatment with nivolumab and ipilimumab at a dose of 3 mg/kg and 1 mg/kg, respectively, every 3 weeks for four doses. Treatment was continued with nivolumab monotherapy at 3 mg/kg every 2 weeks until disease progression or a maximum of 2 years. The primary endpoint was the proportion of patients with disease control at week 12 (complete response, partial response or stable disease (SD) by Response Evaluation Criteria In Solid Tumor V.1.1). Exploratory evaluations correlated clinical outcomes with tumor programmed death-ligand 1 (PD-L1) expression and tumor mutational burden (TMB). RESULTS: The objective response rate in the radiologically evaluable population was 36% (12/33 patients) and in the intention-to-treat population was 28% (12/43 patients), with additional 7 patients obtaining SD leading to a disease control rate of 58% and 44%, respectively. Durable responses were seen across a range of tumor histologies. Thirty-one (72%) patients experienced an immune-related adverse event (irAE) with a grade 3/4 irAE observed in seven (16%) patients. Response rate was higher among those patients with baseline PD-L1 expression (≥1% on tumor cells) but was independent of TMB. CONCLUSIONS: Ipilimumab and nivolumab combination treatment has significant clinical activity with a favorable safety profile across a range of advanced rare gynecological malignancies and warrants further investigation in these tumor types.

Standard-Dose Pembrolizumab Plus Alternate-Dose Ipilimumab in Advanced Melanoma: KEYNOTE-029 Cohort 1C, a Phase 2 Randomized Study of Two Dosing Schedules.

PURPOSE: Standard-dose pembrolizumab plus alternative-dose ipilimumab (1 mg/kg Q3W for 4 doses) were tolerable and had robust antitumor activity in advanced melanoma in cohort B of the phase 1 KEYNOTE-029 study. Cohort C evaluated standard-dose pembrolizumab with two other alternative ipilimumab regimens. PATIENTS AND METHODS: Patients with treatment-naive unresectable stage III/IV melanoma were randomly assigned 1:1 to pembrolizumab 200 mg Q3W for ≤24 months plus ipilimumab 50 mg Q6W for 4 doses (PEM200+IPI50), or the same pembrolizumab regimen plus ipilimumab 100 mg Q12W for 4 doses (PEM200+IPI100). Primary end points were incidence of grade 3-5 treatment-related adverse events (TRAE) and objective response rate (ORR) per RECIST v1.1 by independent central review. Per protocol-defined thresholds, grade 3-5 TRAE incidence ≤26% indicated meaningful toxicity reduction and ORR ≥48% indicated no decrease in efficacy versus data reported for other PD-1 inhibitor/ipilimumab combinations. RESULTS: Median follow-up on February 18, 2019, was 16.3 months in PEM200+IPI50 (N = 51) and 16.4 months in PEM200+IPI100 (N = 51). Grade 3-5 TRAEs occurred in 12 (24%) patients in PEM200+IPI50 and 20 (39%) in PEM200+IPI100. One patient in PEM200+IPI50 died from treatment-related autoimmune myocarditis. Immune-mediated AEs or infusion reactions occurred in 21 (42%) patients in PEM200+IPI50 and 28 (55%) in PEM200+IPI100. ORR was 55% in PEM200+IPI50; 61% in PEM200+IPI100. CONCLUSIONS: Pembrolizumab 200 mg Q3W plus ipilimumab 50 mg Q6W or 100 mg Q12W demonstrated antitumor activity above the predefined threshold; pembrolizumab plus ipilimumab 50 mg Q6W had lower incidence of grade 3-5 TRAEs than the predefined threshold, suggesting a reduction in toxicity. See related commentary by Jameson-Lee and Luke, p. 5153.

PDCD1 Polymorphisms May Predict Response to Anti-PD-1 Blockade in Patients With Metastatic Melanoma.

A significant number of patients (pts) with metastatic melanoma do not respond to anti-programmed cell death 1 (PD1) therapies. Identifying predictive biomarkers therefore remains an urgent need. We retrospectively analyzed plasma DNA of pts with advanced melanoma treated with PD-1 antibodies, nivolumab or pembrolizumab, for five PD-1 genotype single nucleotide polymorphisms (SNPs): PD1.1 (rs36084323, G>A), PD1.3 (rs11568821, G>A), PD1.5 (rs2227981, C>T) PD1.6 (rs10204225, G>A) and PD1.9 (rs2227982, C>T). Clinico-pathological and treatment parameters were collected, and presence of SNPs correlated with response, progression free survival (PFS) and overall survival (OS). 115 patients were identified with a median follow up of 18.7 months (range 0.26 - 52.0 months). All were Caucasian; 27% BRAF V600 mutation positive. At PD-1 antibody commencement, 36% were treatment-naïve and 52% had prior ipilimumab. The overall response rate was 43%, 19% achieving a complete response. Overall median PFS was 11.0 months (95% CI 5.4 - 17.3) and median OS was 31.1 months (95% CI 23.2 - NA). Patients with the G/G genotype had more complete responses than with A/G genotype (16.5% vs. 2.6% respectively) and the G allele of PD1.3 rs11568821 was significantly associated with a longer median PFS than the AG allele, 14.1 vs. 7.0 months compared to the A allele (p=0.04; 95% CI 0.14 - 0.94). No significant association between the remaining SNPs and responses, PFS or OS were observed. Despite limitations in sample size, this is the first study to demonstrate an association of a germline PD-1 polymorphism and PFS in response to anti-PD-1 therapy in pts with metastatic melanoma. Extrinsic factors like host germline polymorphisms should be considered with tumor intrinsic factors as predictive biomarkers for immune checkpoint regulators.

Blockade of the co-inhibitory molecule PD-1 unleashes ILC2-dependent antitumor immunity in melanoma.

Group 2 innate lymphoid cells (ILC2s) are essential to maintain tissue homeostasis. In cancer, ILC2s can harbor both pro-tumorigenic and anti-tumorigenic functions, but we know little about their underlying mechanisms or whether they could be clinically relevant or targeted to improve patient outcomes. Here, we found that high ILC2 infiltration in human melanoma was associated with a good clinical prognosis. ILC2s are critical producers of the cytokine granulocyte-macrophage colony-stimulating factor, which coordinates the recruitment and activation of eosinophils to enhance antitumor responses. Tumor-infiltrating ILC2s expressed programmed cell death protein-1, which limited their intratumoral accumulation, proliferation and antitumor effector functions. This inhibition could be overcome in vivo by combining interleukin-33-driven ILC2 activation with programmed cell death protein-1 blockade to significantly increase antitumor responses. Together, our results identified ILC2s as a critical immune cell type involved in melanoma immunity and revealed a potential synergistic approach to harness ILC2 function for antitumor immunotherapies.

A novel BH3-mimetic, AZD0466, targeting BCL-XL and BCL-2 is effective in pre-clinical models of malignant pleural mesothelioma.

Malignant pleural mesothelioma (MPM) is an aggressive cancer with treatment limited to Cisplatin and Pemetrexed chemotherapy. Recently, we showed that drugs targeting the BCL-2-regulated apoptosis pathway could kill MPM cell lines in vitro, and control tumor growth in vivo. These studies showed BCL-XL was the dominant pro-survival BCL-2 family member correlating with its high-level expression in cells and patient tumor samples. In this study we show another inhibitor, AZD4320 that targets BCL-XL (and BCL-2), can also potently kill MPM tumor cells in vitro (EC50 values in the 200 nM range) and this effect is enhanced by co-inhibition of MCL-1 using AZD5991. Moreover, we show that a novel nanoparticle, AZD0466, where AZD4320 is chemically conjugated to a PEGylated poly-lysine dendrimer, was as effective as standard-of-care chemotherapy, Cisplatin, at inhibiting tumor growth in mouse xenograft studies, and this effect was enhanced when both drugs were combined. Critically, the degree of thrombocytopenia, an on-target toxicity associated with BCL-XL inhibition, was significantly reduced throughout the treatment period compared to other BCL-XL-targeting BH3-mimetics. These pre-clinical findings provide a rationale for the future clinical evaluation for novel BH3-mimetic formulations in MPM, and indeed, other solid tumor types dependent on BCL-XL.

Combination immunotherapy with ipilimumab and nivolumab in patients with advanced adrenocortical carcinoma: a subgroup analysis of CA209-538.

Background: Adrenocortical carcinoma is a rare malignancy, with poor prognosis and limited treatment options for patients with advanced disease. Chemotherapy is the current standard first-line treatment, providing only a modest survival benefit. There is only limited treatment experience with immunotherapy using single-agent anti-PD-1/PD-L1 therapy. To date no clinical trials have been reported using combination immunotherapy with anti-CTLA-4 and anti-PD-1 blockade in this patient population. Methods: CA209-538 is a prospective multicentre clinical trial in patients with advanced rare cancers. Participants received the anti-PD-1 antibody nivolumab (3 mg/kg IV) and the anti-CTLA-4 antibody ipilimumab (1 mg/kg IV) every three weeks for four doses, followed by nivolumab (3 mg/kg IV) every two weeks and continued for up to 96 weeks, until disease progression or unacceptable toxicity. Response was assessed every 12 weeks by RECIST version 1.1. Primary endpoint was clinical benefit rate (complete response, partial response, stable disease at 12 weeks). Results: Six patients with adrenocortical carcinoma were enrolled and received treatment. Two patients (33%) have an ongoing partial response (10 and 25 months +) and two patients (33%) stable disease leading to a disease control rate of 66%. Both responders had tumors with a microsatellite instable phenotype. One patient rapidly progressed shortly after enrollment into the trial and did not undergo restaging. Immunotherapy-related toxicity was reported in all patients, with four patients (67%) experiencing grade 3/4 hepatitis leading to discontinuation of treatment. Conclusions: This is the first treatment experience using ipilimumab and nivolumab combination immunotherapy in patients with advanced adrenocortical carcinoma. Durable responses have been observed in a subset of patients suggesting that this treatment regimen should be further investigated in this patient population.

Ropporin-1 and 1B Are Widely Expressed in Human Melanoma and Evoke Strong Humoral Immune Responses.

Antibodies that block immune regulatory checkpoints (programmed cell death 1, PD-1 and cytotoxic T-lymphocyte-associated antigen 4, CTLA-4) to mobilise immunity have shown unprecedented clinical efficacy against cancer, demonstrating the importance of antigen-specific tumour recognition. Despite this, many patients still fail to benefit from these treatments and additional approaches are being sought. These include mechanisms that boost antigen-specific immunity either by vaccination or adoptive transfer of effector cells. Other than neoantigens, epigenetically regulated and shared antigens such as NY-ESO-1 are attractive targets; however, tissue expression is often heterogeneous and weak. Therefore, peptide-specific therapies combining multiple antigens rationally selected to give additive anti-cancer benefits are necessary to achieve optimal outcomes. Here, we show that Ropporin-1 (ROPN1) and 1B (ROPN1B), cancer restricted antigens, are highly expressed and immunogenic, inducing humoral immunity in patients with advanced metastatic melanoma. By multispectral immunohistochemistry, 88.5% of melanoma patients tested (n = 54/61) showed ROPN1B expression in at least 1 of 2/3 tumour cores in tissue microarrays. Antibody responses against ROPN1A and ROPN1B were detected in 71.2% of melanoma patients tested (n = 74/104), with increased reactivity seen with more advanced disease stages. Thus, ROPN1A and ROPN1B may indeed be viable targets for cancer immunotherapy, alone or in combination with other cancer antigens, and could be combined with additional therapies such as immune checkpoint blockade.

Migratory cues controlling B-lymphocyte trafficking in human lymph nodes.

B-cell migration within lymph nodes (LNs) is crucial to adaptive immune responses. Chemotactic gradients are proposed to drive migration of B cells into follicles, followed by their relocation to specific zones of the follicle during activation, and ultimately egress. However, the molecular drivers of these processes and the cells generating chemotactic signals that affect B cells in human LNs are not well understood. We used immunofluorescence microscopy, flow cytometry and functional assays to study molecular mechanisms of B-cell migration within human LNs, and found subtle but important differences to previous murine models. In human LNs we find CXCL13 is prominently expressed at the follicular edge, often associated with fibroblastic reticular cells located in these areas, whereas follicular dendritic cells show minimal contribution to CXCL13 expression. Human B cells rapidly downregulate CXCR5 on encountering CXCL13, but recover CXCR5 expression in the CXCL13-low environment. These data suggest that the CXCL13 gradient in human LNs is likely to be different from that proposed in mice. We also identify CD68+ CD11c+ PU.1+ tingible body macrophages within both primary and secondary follicles as likely drivers of the sphingosine-1-phosphate (S1P) gradient that mediates B-cell egress from LNs, through their expression of the S1P-degrading enzyme, S1P lyase. Based on our findings, we present a model of B-cell migration within human LNs, which has both similarities and interesting differences to that proposed for mice.

BCL-XL is an actionable target for treatment of malignant pleural mesothelioma.

Despite having one of the lowest survival rates of all cancers, there have been no new approved treatments for malignant pleural mesothelioma (MPM) in over a decade. Standard-of-care treatment relies on Cisplatin plus Pemetrexed chemotherapy. Here, we tested a suite of BH3-mimetic drugs targeting BCL-2 pro-survival proteins of the intrinsic apoptotic pathway. We found BCL-XL is the dominant pro-survival protein in a panel of cell lines in vitro, though potent, synergistic cell killing occurred with MCL-1 co-targeting. This correlates with high-level expression of BCL-XL and MCL-1 in cell lines and a large cohort of patient tumour samples. BCL-XL inhibition combined with Cisplatin also enhanced cell killing. In vivo BCL-XL inhibition was as effective as Cisplatin, and the combination enhanced tumour growth control and survival. Genetic ablation of MCL-1 also enhanced the effects of BCL-XL inhibitors, in vivo. Combined, these data provide a compelling rationale for the clinical investigation of BH3-mimetics targeting BCL-XL in MPM.

Spliced Peptides and Cytokine-Driven Changes in the Immunopeptidome of Melanoma.

Antigen recognition by CD8+ T cells is governed by the pool of peptide antigens presented on the cell surface in the context of HLA class I complexes. Studies have shown not only a high degree of plasticity in the immunopeptidome, but also that a considerable fraction of all presented peptides is generated through proteasome-mediated splicing of noncontiguous regions of proteins to form novel peptide antigens. Here, we used high-resolution mass spectrometry combined with new bioinformatic approaches to characterize the immunopeptidome of melanoma cells in the presence or absence of IFNγ. In total, we identified more than 60,000 peptides from a single patient-derived cell line (LM-MEL-44) and demonstrated that IFNγ induced changes in the peptidome, with an overlap of only approximately 50% between basal and treated cells. Around 6% to 8% of the peptides were identified as cis-spliced peptides, and 2,213 peptides (1,827 linear and 386 cis-spliced peptides) were derived from known melanoma-associated antigens. These peptide antigens were equally distributed between the constitutive- and IFNγ-induced peptidome. We next examined additional HLA-matched patient-derived cell lines to investigate how frequently these peptides were identified and found that a high proportion of both linear and spliced peptides was conserved between individual patient tumors, drawing on data amassing to more than 100,000 peptide sequences. Several of these peptides showed in vitro immunogenicity across multiple patients with melanoma. These observations highlight the breadth and complexity of the repertoire of immunogenic peptides that can be exploited therapeutically and suggest that spliced peptides are a major class of tumor antigens.

Histological diagnosis of immune checkpoint inhibitor induced acute renal injury in patients with metastatic melanoma: a retrospective case series report.

BACKGROUND: Immune checkpoint inhibitors (ICI) have become the standard of care in many oncological conditions but are associated with a spectrum of renal immune-related adverse events (IrAEs). We aimed to describe the spectrum, histology, management and outcomes of renal IrAE in patients with metastatic melanoma undergoing ICI therapy. METHODS: We conducted a retrospective review of 23 patients with a diagnosis of metastatic melanoma treated with ICI between January 2017 and April 2019 who developed a renal IrAE. Baseline demographic data, biochemical and histopathological results, management and outcomes were analyzed. RESULTS: The majority of patients who developed renal irAE were male and received combination immunotherapy. The median time of onset from initiation of ICI therapy to renal IrAE was 4 months. 52% of the treated renal IrAE had histopathologically confirmed renal IrAE. The most common histological pattern of injury was acute tubulo-interstitial nephritis (92%). One patient developed anti-GBM disease with non-dialysis dependent stage 5 CKD. In tubulointerstitial injury, there was no association between peak creatinine, renal recovery and histologically reported inflammation or fibrosis. Patients with renal IrAE demonstrated persisting renal dysfunction at 3, 6 and 12 months with a mean baseline, 3 and 12 month creatinine of 90.0 µmol/L, 127.0 µmol/L and 107.5 µmol/L respectively. CONCLUSION: Renal IrAE is most commonly attributable to steroid responsive acute tubulointerstitial nephritis. The outcome of rarer pathologies such as anti-GBM disease may be adversely affected by a delayed diagnosis. There is persisting renal dysfunction following an episode of renal IrAE that may have impact on future renal and overall survival outcomes.

Long-term Follow-up of Standard-Dose Pembrolizumab Plus Reduced-Dose Ipilimumab in Patients with Advanced Melanoma: KEYNOTE-029 Part 1B.

PURPOSE: Combination therapy with reduced-dose programmed death 1 inhibitor plus standard-dose cytotoxic T-lymphocyte-associated antigen 4 inhibitor demonstrated efficacy, but substantial toxicity, in melanoma. We present long-term results of part 1B of KEYNOTE-029, which assessed safety and efficacy of standard-dose pembrolizumab plus reduced-dose ipilimumab in advanced melanoma. PATIENTS AND METHODS: Part 1B was an expansion cohort of the open-label, phase Ib portion of KEYNOTE-029. Eligible patients had advanced melanoma and no previous immune checkpoint inhibitor therapy. Patients received pembrolizumab 2 mg/kg (amended to 200 mg) every 3 weeks plus ipilimumab 1 mg/kg every 3 weeks (four cycles), then pembrolizumab alone for up to 2 years. Primary end point was safety; secondary end points included objective response rate (ORR), progression-free survival (PFS), duration of response (DOR), and overall survival (OS). RESULTS: A total of 153 patients received at least one dose of pembrolizumab plus ipilimumab. At a median follow-up of 36.8 months, 71.9% had received four doses of ipilimumab and 30.7% had completed 2 years of pembrolizumab; 26.1% completed both treatments. Treatment-related adverse events occurred in 96.1% (47.1% grade 3/4; no deaths), leading to discontinuation of one or both study drugs in 35.9%. ORR was 62.1% with 42 (27.5%) complete and 53 (34.6%) partial responses. Median DOR was not reached; 36-month ongoing response rate was 84.2%. Median PFS and OS were not reached; 36-month rates were 59.1% and 73.4%, respectively. CONCLUSIONS: Standard-dose pembrolizumab plus reduced-dose ipilimumab demonstrated robust antitumor activity, durable response, and favorable long-term survival with manageable toxicity.

Evaluation of Combination Nivolumab and Ipilimumab Immunotherapy in Patients With Advanced Biliary Tract Cancers: Subgroup Analysis of a Phase 2 Nonrandomized Clinical Trial.

Importance: Biliary tract cancers represent a rare group of malignant conditions with very limited treatment options. Patients with advanced disease have a poor outcome with current therapies. Objective: To evaluate the efficacy and safety of combination immunotherapy with nivolumab and ipilimumab in patients with advanced biliary tract cancers. Design, Setting, and Participants: The CA209-538 prospective multicenter phase 2 nonrandomized clinical trial included patients with advanced rare cancers including patients with biliary tract cancers. This subgroup analysis evaluated 39 patients from CA209-538 with biliary tract cancers who were enrolled from December 2017 to December 2019. Most of the patients (n = 33) had experienced disease progression after 1 or more lines of therapy and had tumor tissue available for biomarker research. Interventions: Patients received treatment with nivolumab at a dose of 3 mg/kg and ipilimumab at 1 mg/kg every 3 weeks for 4 doses, followed by nivolumab 3 mg/kg every 2 weeks and continued for up to 96 weeks until disease progression or the development of unacceptable toxic events. Main Outcomes and Measures: The primary end point was disease control rate (complete remission, partial remission, or stable disease) as assessed by RECIST 1.1. Results: Among the 39 patients included in this subgroup analysis of a phase 2 clinical trial (20 men, 19 women; mean [range] age, 65 [37-81] years), the objective response rate was 23% (n = 9) with a disease control rate of 44% (n = 17); all responders had received prior chemotherapy, and none had a microsatellite unstable tumor. Responses were exclusively observed in patients with intrahepatic cholangiocarcinoma and gallbladder carcinoma. The median duration of response was not reached (range, 2.5 to ≥23 months). The median progression-free survival was 2.9 months (95% CI, 2.2-4.6 months), and overall survival was 5.7 months (95% CI, 2.7-11.9 months). Immune-related toxic events were reported in 49% of patients (n = 19), with 15% (n = 6) experiencing grade 3 or 4 events. Conclusions and Relevance: This subgroup analysis of a phase 2 clinical trial found that combination immunotherapy with nivolumab and ipilimumab was associated with substantial positive outcomes patients with advanced biliary tract cancers. This treatment compares favorably to single-agent anti-programmed cell death protein 1 (anti-PD-1) therapy and warrants further investigation. Ongoing translational research is focused on identifying biomarkers that can predict treatment response. Trial Registration: ClinicalTrials.gov Identifier: NCT02923934.

Distinctive Subpopulations of Stromal Cells Are Present in Human Lymph Nodes Infiltrated with Melanoma.

Metastasis of human tumors to lymph nodes (LN) is a universally negative prognostic factor. LN stromal cells (SC) play a crucial role in enabling T-cell responses, and because tumor metastases modulate their structure and function, this interaction may suppress immune responses to tumor antigens. The SC subpopulations that respond to infiltration of malignant cells into human LNs have not been defined. Here, we identify distinctive subpopulations of CD90+ SCs present in melanoma-infiltrated LNs and compare them with their counterparts in normal LNs. The first population (CD90+ podoplanin+ CD105+ CD146+ CD271+ VCAM-1+ ICAM-1+ α-SMA+) corresponds to fibroblastic reticular cells that express various T-cell modulating cytokines, chemokines, and adhesion molecules. The second (CD90+ CD34+ CD105+ CD271+) represents a novel population of CD34+ SCs embedded in collagenous structures, such as the capsule and trabeculae, that predominantly produce extracellular matrix. We also demonstrated that these two SC subpopulations are distinct from two subsets of human LN pericytes, CD90+ CD146+ CD36+ NG2- pericytes in the walls of high endothelial venules and other small vessels, and CD90+ CD146+ NG2+ CD36- pericytes in the walls of larger vessels. Distinguishing between these CD90+ SC subpopulations in human LNs allows for further study of their respective impact on T-cell responses to tumor antigens and clinical outcomes.