Molecular Pathways of Colon Inflammation Induced by Cancer Immunotherapy.

Checkpoint blockade with antibodies specific for the PD-1 and CTLA-4 inhibitory receptors can induce durable responses in a wide range of human cancers. However, the immunological mechanisms responsible for severe inflammatory side effects remain poorly understood. Here we report a comprehensive single-cell analysis of immune cell populations in colitis, a common and severe side effect of checkpoint blockade. We observed a striking accumulation of CD8 T cells with highly cytotoxic and proliferative states and no evidence of regulatory T cell depletion. T cell receptor (TCR) sequence analysis demonstrated that a substantial fraction of colitis-associated CD8 T cells originated from tissue-resident populations, explaining the frequently early onset of colitis symptoms following treatment initiation. Our analysis also identified cytokines, chemokines, and surface receptors that could serve as therapeutic targets for colitis and potentially other inflammatory side effects of checkpoint blockade.

Ziv-aflibercept plus pembrolizumab in patients with advanced melanoma resistant to anti-PD-1 treatment.

BACKGROUND: Vascular endothelial growth factor is associated with reduced immune response and impaired anti-tumor activity. Combining antiangiogenic agents with immune checkpoint inhibition can overcome this immune suppression and enhance treatment efficacy. METHODS: This study investigated the combination of ziv-aflibercept anti-angiogenic therapy with pembrolizumab in patients with advanced melanoma resistant to anti-PD-1 treatment. Baseline and on-treatment plasma and PBMC samples were analyzed by multiplex protein assay and mass cytometry, respectively. RESULTS: In this Phase 1B study (NCT02298959), ten patients with advanced PD-1-resistant melanoma were treated with a combination of ziv-aflibercept (at 2-4 mg/kg) plus pembrolizumab (at 2 mg/kg), administered intravenously every 2 weeks. Two patients (20%) achieved a partial response, and two patients (20%) experienced stable disease (SD) as the best response. The two responders had mucosal melanoma, while both patients with SD had ocular melanoma. The combination therapy demonstrated clinical activity and acceptable safety, despite the occurrence of adverse events. Changes in plasma analytes such as platelet-derived growth factor and PD-L1 were explored, indicating potential alterations in myeloid cell function. Higher levels of circulating CXCL10 in non-responding patients may reflect pro-tumor activity. Specific subsets of γδ T cells were associated with poor clinical outcomes, suggesting impaired γδ T-cell function in non-responding patients. CONCLUSIONS: Although limited by sample size and follow-up, these findings highlight the potential of the combination of ziv-aflibercept antiangiogenic therapy with pembrolizumab in patients with advanced melanoma resistant to anti-PD-1 treatment and the need for further research to improve outcomes in anti-PD-1-resistant melanoma. TRIAL REGISTRATION NUMBER: NCT02298959.

Profiling of Natural Killer Interactions With Cancer Cells Using Mass Cytometry.

We developed a comprehensive method for functional assessment of the changes in immune populations and killing activity of peripheral blood mononuclear cells after cocultures with cancer cells using mass cytometry. In this study, a 43-marker mass cytometry panel was applied to a coculture of immune cells from healthy donors' peripheral blood mononuclear cells with diverse cancer cell lines. DNA content combined with classical CD45 surface staining was used as gating parameters for cocultures of immune cells (CD45high/DNAlow) with hematological (CD45low/DNAhigh) and solid cancer cell lines (CD45neg/DNAhigh). This strategy allows for universal discrimination of cancer cells from immune populations without the need for a specific cancer cell marker and simultaneous assessment of phenotypical changes in both populations. The use of mass cytometry allows for simultaneous detection of changes in natural killer, natural killer T cell, and T cell phenotypes and degranulation of immune populations upon target recognition, analysis of target cells for cytotoxic protein granzyme B content, and cancer cell death. These findings have broad applicability in research and clinical settings with the aim to phenotype and assess functional changes following not only NK-cancer cell interactions but also the effect of those interactions on other immune populations.

Effect of corticosteroid dosing on outcomes in high-grade immune checkpoint inhibitor hepatitis.

BACKGROUND AND AIMS: Consensus guidelines recommend high-dose corticosteroids (1-2 mg/kg/day methylprednisolone equivalents) for treating grade ≥3 immune checkpoint inhibitor (ICI) hepatitis. We examined the effect of corticosteroid dosing on time to alanine aminotransferase (ALT) normalization, need for additional immunosuppression, and steroid-related complications. APPROACH AND RESULTS: We conducted a retrospective cohort study of 215 ICI-treated patients from 2010 to 2020 who developed grade ≥3 (ALT > 200 U/L) ICI hepatitis. Patients were grouped by initial corticosteroid dose (≥1.5 mg/kg or <1.5 mg/kg methylprednisolone equivalents). Propensity scores were calculated predicting the risk of receiving the higher steroid dose and used in inverse probability of treatment weighted (IPTW) logistic or Cox regression. The 87 patients in the ≥1.5 mg/kg group received higher initial (2.0 vs. 0.8 mg/kg/day, p < 0.001) and maximum (2.0 vs. 1.0 mg/kg/day, p < 0.001) steroid doses than the 128 patients in the <1.5 mg/kg group. There was no difference between the higher versus lower-dose groups in development of steroid-refractory hepatitis (OR 1.22, 95% CI 0.79-1.89, p = 0.365) on IPTW-logistic regression. In patients with steroid-responsive disease, there was no difference between the two groups in time to ALT normalization using either standard Cox regression (HR 1.02, 95% CI 0.72-1.45, p = 0.903) or IPTW-Cox regression (HR 1.09, 95% CI 0.78-1.51, p = 0.610). The ≥1.5 mg/kg group had longer exposure to corticosteroids (median 60 vs. 44 days, p = 0.005) and higher incidences of infection (18.4% vs. 7.0%, relative risk [RR] 2.6, 95% CI 1.2-5.6, p = 0.011) and hyperglycemia requiring treatment (23.3% vs. 7.8%, RR 3.0, 95% CI 1.5-6.0, p = 0.001). CONCLUSIONS: In patients with high-grade ICI hepatitis, initial treatment with 1 mg/kg/day methylprednisolone equivalents provides similar hepatitis outcomes with reduced risk of steroid-related complications when compared with higher-dose regimens.

CD40 agonistic monoclonal antibody APX005M (sotigalimab) and chemotherapy, with or without nivolumab, for the treatment of metastatic pancreatic adenocarcinoma: an open-label, multicentre, phase 1b study.

BACKGROUND: Standard chemotherapy remains inadequate in metastatic pancreatic adenocarcinoma. Combining an agonistic CD40 monoclonal antibody with chemotherapy induces T-cell-dependent tumour regression in mice and improves survival. In this study, we aimed to evaluate the safety of combining APX005M (sotigalimab) with gemcitabine plus nab-paclitaxel, with and without nivolumab, in patients with pancreatic adenocarcinoma to establish the recommended phase 2 dose. METHODS: This non-randomised, open-label, multicentre, four-cohort, phase 1b study was done at seven academic hospitals in the USA. Eligible patients were adults aged 18 years and older with untreated metastatic pancreatic adenocarcinoma, Eastern Cooperative Oncology Group performance status score of 0-1, and measurable disease by Response Evaluation Criteria in Solid Tumors version 1.1. All patients were treated with 1000 mg/m2 intravenous gemcitabine and 125 mg/m2 intravenous nab-paclitaxel. Patients received 0·1 mg/kg intravenous APX005M in cohorts B1 and C1 and 0·3 mg/kg in cohorts B2 and C2. In cohorts C1 and C2, patients also received 240 mg intravenous nivolumab. Primary endpoints comprised incidence of adverse events in all patients who received at least one dose of any study drug, incidence of dose-limiting toxicities (DLTs) in all patients who had a DLT or received at least two doses of gemcitabine plus nab-paclitaxel and one dose of APX005M during cycle 1, and establishing the recommended phase 2 dose of intravenous APX005M. Objective response rate in the DLT-evaluable population was a key secondary endpoint. This trial (PRINCE, PICI0002) is registered with ClinicalTrials.gov, NCT03214250 and is ongoing. FINDINGS: Between Aug 22, 2017, and July 10, 2018, of 42 patients screened, 30 patients were enrolled and received at least one dose of any study drug; 24 were DLT-evaluable with median follow-up 17·8 months (IQR 16·0-19·4; cohort B1 22·0 months [21·4-22·7], cohort B2 18·2 months [17·0-18·9], cohort C1 17·9 months [14·3-19·7], cohort C2 15·9 months [12·7-16·1]). Two DLTs, both febrile neutropenia, were observed, occurring in one patient each for cohorts B2 (grade 3) and C1 (grade 4). The most common grade 3-4 treatment-related adverse events were lymphocyte count decreased (20 [67%]; five in B1, seven in B2, four in C1, four in C2), anaemia (11 [37%]; two in B1, four in B2, four in C1, one in C2), and neutrophil count decreased (nine [30%]; three in B1, three in B2, one in C1, two in C2). 14 (47%) of 30 patients (four each in B1, B2, C1; two in C2) had a treatment-related serious adverse event. The most common serious adverse event was pyrexia (six [20%] of 30; one in B2, three in C1, two in C2). There were two chemotherapy-related deaths due to adverse events: one sepsis in B1 and one septic shock in C1. The recommended phase 2 dose of APX005M was 0·3 mg/kg. Responses were observed in 14 (58%) of 24 DLT-evaluable patients (four each in B1, C1, C2; two in B2). INTERPRETATION: APX005M and gemcitabine plus nab-paclitaxel, with or without nivolumab, is tolerable in metastatic pancreatic adenocarcinoma and shows clinical activity. If confirmed in later phase trials, this treatment regimen could replace chemotherapy-only standard of care in this population. FUNDING: Parker Institute for Cancer Immunotherapy, Cancer Research Institute, and Bristol Myers Squibb.

A multi-center study on safety and efficacy of immune checkpoint inhibitors in cancer patients with kidney transplant.

Immune checkpoint inhibitors (ICIs) are widely used for various malignancies. However, their safety and efficacy in patients with a kidney transplant have not been defined. To delineate this, we conducted a multicenter retrospective study of 69 patients with a kidney transplant receiving ICIs between January 2010 and May 2020. For safety, we assessed the incidence, timing, and risk factors of acute graft rejection. For efficacy, objective response rate and overall survival were assessed in cutaneous squamous cell carcinoma and melanoma, the most common cancers in our cohort, and compared with stage-matched 23 patients with squamous cell carcinoma and 14 with melanoma with a kidney transplant not receiving ICIs. Following ICI treatment, 29 out of 69 (42%) patients developed acute rejection, 19 of whom lost their allograft, compared with an acute rejection rate of 5.4% in the non-ICI cohort. Median time from ICI initiation to rejection was 24 days. Factors associated with a lower risk of rejection were mTOR inhibitor use (odds ratio 0.26; 95% confidence interval, 0.09-0.72) and triple-agent immunosuppression (0.67, 0.48-0.92). The objective response ratio was 36.4% and 40% in the squamous cell carcinoma and melanoma subgroups, respectively. In the squamous cell carcinoma subgroup, overall survival was significantly longer in patients treated with ICIs (median overall survival 19.8 months vs. 10.6 months), whereas in the melanoma subgroup, overall survival did not differ between groups. Thus, ICIs were associated with a high risk of rejection in patients with kidney transplants but may lead to improved cancer outcomes. Prospective studies are needed to determine optimal immunosuppression strategies to improve patient outcomes.

Cytokine changes during immune-related adverse events and corticosteroid treatment in melanoma patients receiving immune checkpoint inhibitors.

BACKGROUND: Immune checkpoint inhibitors (ICIs) often cause immune-related adverse events (irAEs), most of which are treated with corticosteroids despite evidence suggesting that corticosteroids may blunt antitumor efficacy. We sought to identify cytokine changes that correlate with irAEs and study the impact of corticosteroid treatment on cytokine levels. METHODS: We analyzed expression of 34 cytokines in 52 melanoma patients who developed irAEs during therapy with ICIs. Luminex serum assay was performed at baseline, 1, 2, and 3 months after starting ICI. Baseline cytokine levels and longitudinal log2 fold-change was compared with incidence and grade of irAEs. Cytokine patterns were compared between patients based on development of irAEs and steroid treatment. RESULTS: There were no differences in baseline cytokine levels between patients who developed grade 1-2 irAEs (N = 28) vs. grade 3-4 irAEs (N = 24). Dermatitis patients (N = 8) had significantly higher baseline Ang-1 (p = 0.006) and CD40L (p = 0.005). Pneumonitis patients (N = 4) had significantly higher baseline IL-17 (p = 0.009). Colitis patients (N = 8) had a trend toward decreased GCSF (p = 0.08). Through Spearman's correlation analysis, patients who developed irAEs without receiving corticosteroids (N = 23) exhibited harmonization of cytokine fold-change, with 0/276 pairwise comparisons demonstrating significant divergence. In contrast, corticosteroid treatment in patients with irAEs (N = 15) altered fold-change to a discordant pattern (42/276 diverged, 15.2%). This discordant cytokine pattern in patients receiving corticosteroids is similar to the cytokine pattern in patients who did not develop irAEs (N = 8) during the longitudinal profiling period (41/276, 14.9%). CONCLUSIONS: Baseline levels of certain cytokines correlate with specific irAEs in melanoma patients receiving ICIs. irAEs drive a concordant pattern of cytokine fold-change, which is disrupted by corticosteroid treatment.

Medication-specific variations in morphological patterns of injury in immune check-point inhibitor-associated colitis.

AIMS: A varied spectrum of histopathological changes has been associated with immune checkpoint inhibitor (ICI) colitis. This study was performed to evaluate the prevalence of different histopathological patterns of injury in patients with ICI colitis and their association with specific immune check-point inhibitors. METHODS AND RESULTS: Biopsies from patients with clinically and histologically confirmed ICI colitis were reviewed blindly to determine the predominant pattern of injury and to quantitate discrete histological parameters using the Geboes score. Paneth cell metaplasia, intraepithelial lymphocytes, abnormal subepithelial collagen and degree of crypt epithelial apoptosis was also recorded. A total of 86 patients with ICI colitis (ipilimumab, n = 14; ipilimumab + nivolumab, n = 29; nivolumab, n = 20 and pembrolizumab, n = 23) were included. The patterns of injury identified included diffuse active colitis (n = 22), chronic active colitis (n = 22), lymphocytic colitis (LC, n = 16), collagenous colitis (CC, n = 14), graft-versus-host disease-like colitis (n = 7) and mixed colitis (n = 5). Patients on ipilimumab were more likely to have a diffuse active colitis pattern without features of chronicity (P < 0.01) and less likely to have LC (P < 0.05) compared to other ICIs. LC and CC were more common in patients on nivolumab and pembrolizumab relative to other groups (P < 0.05). Chronic active colitis was most frequent in nivolumab patients (P < 0.05), and these patients had received more ICI doses and had been on ICI treatment longer compared to other treatment groups. CONCLUSIONS: ICI colitis should be considered in the differential diagnosis of all the common inflammatory patterns of colitis and shows medication specific differences in patterns of injury.

Pancreatic acinar cell carcinoma: A multi-center series on clinical characteristics and treatment outcomes.

BACKGROUND: Acinar cell carcinoma (ACC) is a very rare tumor of the exocrine pancreas, representing less than 1% of all pancreatic malignancies. The majority of data regarding ACC are limited to small case series. METHODS: This is a retrospective study conducted at a large healthcare system from 1996 to 2019. Patients with pathologically confirmed ACC were included, and demographic data, tumor characteristics, and treatment outcomes were abstracted by chart review. Survival curves were obtained by using the Kaplan-Meier method and compared using the log-rank test. RESULTS: Sixty-six patients with ACC were identified. The median patient age at diagnosis was 64, and 42% presented with metastatic disease. The majority presented with abdominal pain or pancreatitis (69%), and laboratory parameters did not correlate with tumor size, metastatic disease, or survival. Several somatic abnormalities were noted in tumors (BRCA2, TP53, and mismatch-repair genes). In patients with localized disease that underwent resection, the median time to develop metastatic lesions was 13 months. The median overall survival (OS) was 24.7 months from diagnosis, with a survival difference based on metastatic disease at diagnosis (median 15 vs 38 mos). Surgery was associated with improved survival in non-metastatic cases (p = 0.006) but not metastatic cases (p = 0.22), and chemotherapy showed OS benefit in metastatic disease (p < 0.01). Patients with metastatic ACC treated after 2010 utilized more platinum-based agents, and there was a OS benefit to FOLFOX or FOLFIRINOX chemotherapy compared to gemcitabine or capecitabine-based regimens (p = 0.006). CONCLUSION: Pancreatic ACC patients often present with advanced disease. Surgery was associated with survival benefit among patients presenting with localized disease. The use of FOLFOX or FOLFIRINOX chemotherapy regimens was associated with improved OS in metastatic patients. These data add to our knowledge in this rare malignancy, and improves understanding about the genomic underpinnings, prognosis and treatment for acinar cancers.

Gastroparesis Following Immune Checkpoint Inhibitor Therapy: A Case Series.

BACKGROUND: Immune checkpoint inhibitors (ICI) have improved outcomes in patients with various malignancies; however, they can cause immune-related hepatitis and enterocolitis. Patients on ICI may also develop upper gastrointestinal symptoms and undergo measurement of gastric emptying. AIMS: Our aim was to review records of patients with gastroparesis following ICI therapy at two medical centers. METHODS: We performed a retrospective review of all patients at Mayo Clinic and Brigham and Women's/Dana-Farber Cancer Center (BWH/DFCC) who underwent gastric scintigraphy for the assessment of symptoms of gastroparesis following ICI treatment up to January 2020. Clinical presentation, medical history, laboratory evaluation, imaging, treatment, and outcomes were retrieved from the records. Gastroparesis was diagnosed as delayed gastric emptying (GE) measured by gastric scintigraphy. RESULTS: At Mayo Clinic, 2 patients (median age 59 years, 1 male [M], 1 female [F]) had delayed GE, while 4 patients (median age 53 years, 3M, 1F) had normal GE following ICI use. Of those with delayed GE (diagnosed after 38 and 2 months of ICI initiation), 1 patient was treated for non-Hodgkin's lymphoma and melanoma with ipilimumab; a second patient with breast cancer was treated with pembrolizumab. At BWH/DFCC, 2 patients (median age 56 years, 1M, 1F) had normal GE after ICI treatment, while a 62-year-old female with non-small cell lung cancer developed gastroparesis 3 months following initiation of nivolumab. CONCLUSION: This report documents gastroparesis as a potential adverse effect of ICI. Further studies should explore the potential for ICI therapy to damage anti-inflammatory macrophages that preserve the enteric neurons.

Outcomes after resumption of immune checkpoint inhibitor therapy after high-grade immune-mediated hepatitis.

BACKGROUND: In the current study, the authors assessed the risks and outcomes of immune checkpoint inhibitor (ICI) rechallenge in patients with resolved grade 3 to 4 ICI hepatitis because current guidelines recommend permanent ICI discontinuation in these patients. METHODS: The authors performed a retrospective cohort study from 2010 through 2019 of patients with melanoma who were treated with ≥1 ICIs and who recovered from grade 3 to 4 ICI hepatitis. The primary outcome was hepatitis recurrence and the secondary outcome was the development of any immune-related adverse event (irAE) requiring the discontinuation of ICI rechallenge. Best overall response and time to all-cause death were compared between the patients who did and those who did not undergo ICI rechallenge. Grading was performed using the National Cancer Institute Common Terminology Criteria for Adverse Events (version 5.0). RESULTS: Of the 102 patients with melanoma who developed high-grade ICI hepatitis, 31 underwent ICI rechallenge. Although 15 of 31 patients (48%) developed an irAE of any grade, only 6 patients (19%) required ICI discontinuation due to irAE severity (4 of 29 patients [14%] rechallenged with anti-PD-1 or anti-PD-L1 and 2 of 2 patients [100%] rechallenged with ipilimumab). Recurrent hepatitis accounted for 4 of these 6 cases. Rechallenged patients who did not require ICI discontinuation were found to be significantly less likely to receive ipilimumab rather than anti-PD-1 or anti-PD-L1 monotherapy (0% vs 33%; relative risk (RR), 0.1 [95% CI, 0.1-0.3; P = .032]) and significantly less likely to be rechallenged with their original ICI (8% vs 50%; RR, 0.2 [95% CI, 0.1-0.7; P = .038]). There was no difference noted with regard to best overall response or time to death between rechallenged and non-rechallenged patients. CONCLUSIONS: ICI therapy can be resumed in patients with melanoma who have recovered from grade 3 to 4 ICI hepatitis with a modest risk of serious irAEs. It remains unclear whether ICI retreatment improves clinical outcomes.

Vitamin D intake is associated with decreased risk of immune checkpoint inhibitor-induced colitis.

BACKGROUND: There is a lack of predictive markers informing on the risk of colitis in patients treated with immune checkpoint inhibitors (ICIs). The aim of this study was to identify potential factors associated with development of ICI colitis. METHODS: We performed a retrospective analysis of melanoma patients at Dana-Farber Cancer Institute who received PD-1, CTLA-4, or combination ICIs between May 2011 to October 2017. Clinical and laboratory characteristics associated with pathologically confirmed ICI colitis were evaluated using multivariable logistic regression analyses. External confirmation was performed on an independent cohort from Massachusetts General Hospital. RESULTS: The discovery cohort included 213 patients of whom 37 developed ICI colitis (17%). Vitamin D use was recorded in 66/213 patients (31%) before starting ICIs. In multivariable regression analysis, vitamin D use conferred significantly reduced odds of developing ICI colitis (OR 0.35, 95% CI 0.1-0.9). These results were also demonstrated in the confirmatory cohort (OR 0.46, 95% CI 0.2-0.9) of 169 patients of whom 49 developed ICI colitis (29%). Pre-treatment neutrophil-to-lymphocyte ratio (NLR) ≥5 predicted reduced odds of colitis (OR 0.34, 95% CI 0.1-0.9) only in the discovery cohort. CONCLUSIONS: This is the first study to report that among patients treated with ICIs, vitamin D intake is associated with reduced risk for ICI colitis. This finding is consistent with prior reports of prophylactic use of vitamin D in ulcerative colitis and graft-versus-host-disease. This observation should be validated prospectively in future studies.

The Safety and Efficacy of Checkpoint Inhibitors in Transplant Recipients: A Case Series and Systematic Review of Literature.

Limited data exist on safety and efficacy of immune checkpoint inhibitors (ICIs) among organ transplant recipients. The objective of this study was to report a case series of two patients with renal transplant who received treatment with an ICI and to conduct a pooled analysis of published cases to describe the safety and efficacy of ICIs in organ transplant patients. A systematic search in the Google Scholar and PubMed databases was carried out to include all the published cases of organ transplant patients who received treatment with ICIs including programmed cell death protein 1 (PD-1), programmed death-ligand 1, or cytotoxic lymphocyte antigen-4 inhibitors since their inscription to January 31, 2019. In the present series of two cases with renal allografts who received pembrolizumab, one patient with squamous cell carcinoma of the skin experienced complete response (CR), whereas another patient with melanoma had a mixed response. Both patients experienced allograft rejection, but graft was salvaged. The pooled analysis of 64 patients published in literature showed that overall allograft rejection rate is 41% in organ transplant recipients following ICI therapy. The graft rejection rate was 44% (17/39) for renal, 39% (7/19) for liver, and 20% (1/5) for cardiac allografts. The highest risk was seen among patients who were treated with PD-1 inhibitors, 20/42 (48%)-13/24 (54%) on nivolumab and 7/18 (39%) on pembrolizumab. The risk was lowest with ipilimumab, 23% (3/13). The overall response rate (CR + partial response [PR]) was 20% with ipilimumab, 26% with nivolumab, and 53% with pembrolizumab, whereas disease control rate (CR + PR + stable disease) was 35% with ipilimumab, 37% with nivolumab, and 53% with pembrolizumab. None of the variables including age, gender, type of cancer, type of allograft, type of immunosuppression, time since transplantation to initiation of ICI, and prior history of rejection were significantly associated with the transplant rejection on univariate analysis. The efficacy of ICI among patients with organ transplant appears promising, warranting testing in prospective clinical trials. The risk of rejection and allograft loss is considerable; therefore, the risk and alternative form of therapies should be thoroughly discussed with the transplant patients prior to initiating ICI therapy. IMPLICATIONS FOR PRACTICE: Transplant recipients are at higher risk of developing cancers. Although immune checkpoint inhibitors have been shown to improve the outcome in more than one cancer type, transplant recipients were excluded from these trials. Most of the data on the safety and efficacy of immune checkpoint inhibitors in transplant patients are based upon case series and case reports. The pooled data from these reports suggest that anti-programmed death-ligand 1 inhibitors have reasonable safety and efficacy among organ transplant patients, which warrants testing in clinical trials.

National Cancer Institute (NCI) state of the science: Targeted radiosensitizers in colorectal cancer.

Colorectal cancer (CRC) represents a major public health problem as the second leading cause of cancer-related mortality in the United States. Of an estimated 140,000 newly diagnosed CRC cases in 2018, roughly one-third of these patients will have a primary tumor located in the distal large bowel or rectum. The current standard-of-care approach includes curative-intent surgery, often after preoperative (neoadjuvant) radiotherapy (RT), to increase rates of tumor down-staging, clinical and pathologic response, as well as improving surgical resection quality. However, despite advancements in surgical techniques, as well as sharpened precision of dosimetry offered by contemporary RT delivery platforms, the oncology community continues to face challenges related to disease relapse. Ongoing investigations are aimed at testing novel radiosensitizing agents and treatments that might exploit the systemic antitumor effects of RT using immunotherapies. If successful, these treatments may usher in a new curative paradigm for rectal cancers, such that surgical interventions may be avoided. Importantly, this disease offers an opportunity to correlate matched paired biopsies, radiographic response, and molecular mechanisms of treatment sensitivity and resistance with clinical outcomes. Herein, the authors highlight the available evidence from preclinical models and early-phase studies, with an emphasis on promising developmental therapeutics undergoing prospective validation in larger scale clinical trials. This review by the National Cancer Institute's Radiation Research Program Colorectal Cancer Working Group provides an updated, comprehensive examination of the continuously evolving state of the science regarding radiosensitizer drug development in the curative treatment of CRC.

Anti-PD-1 Immunotherapy-Induced Flare of a Known Underlying Relapsing Vasculitis Mimicking Recurrent Cancer.

Safe use of immune checkpoint blockade in patients with cancer and autoimmune disorders requires a better understanding of the pathophysiology of immunologic activation. We describe the immune correlates of reactivation of granulomatosis with polyangiitis (GPA)-an antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis-in a patient with metastatic urothelial carcinoma treated with pembrolizumab. After PD-1 blockade, an inflammatory pulmonary nodule demonstrated a granulomatous, CD4+ T-cell infiltrate, correlating with increased CD4+ and CD8+ naïve memory cells in the peripheral blood without changes in other immune checkpoint receptors. Placed within the context of the existing literature on GPA and disease control, our findings suggest a key role for PD-1 in GPA self-tolerance and that selective strategies for immunotherapy may be needed in patients with certain autoimmune disorders. We further summarize the current literature regarding reactivation of autoimmune disorders in patients undergoing immune checkpoint blockade, as well as potential immunosuppressive strategies to minimize the risks of further vasculitic reactivation upon rechallenge with anti-PD-1 blockade. KEY POINTS: Nonspecific imaging findings in patients with cancer and rheumatological disorders may require biopsy to distinguish underlying pathology.Patients with rheumatologic disorders have increased risk of reactivation with PD-(L)1 immune checkpoint blockade, requiring assessment of disease status before starting treatment.Further study is needed to evaluate the efficacy of treatment regimens in preventing and controlling disease reactivation.

Clinical and laboratory features of autoimmune hemolytic anemia associated with immune checkpoint inhibitors.

Immune checkpoint inhibitors (ICPis) are a novel class of immunotherapeutic agents that have revolutionized the treatment of cancer; however, these drugs can also cause a unique spectrum of autoimmune toxicity. Autoimmune hemolytic anemia (AIHA) is a rare, but often severe, complication of ICPis. We identified 14 patients from nine institutions across the United States who developed ICPi-AIHA. The median interval from ICPi initiation to development of AIHA was 55 days (interquartile range [IQR], 22-110 days). Results from the direct antiglobulin test (DAT) were available for 13 of 14 patients: 8 patients (62%) had a positive DAT and 5 (38%) had a negative DAT. The median pretreatment and nadir hemoglobin concentrations were 11.8 g/dL (IQR, 10.2-12.9 g/dL) and 6.3 g/dL (IQR, 6.1-8.0 g/dL), respectively. Four patients (29%) had a preexisting lymphoproliferative disorder, and two (14%) had a positive DAT prior to initiation of ICPi therapy. All patients were treated with glucocorticoids, with three requiring additional immunosuppressive therapy. Complete and partial recoveries of hemoglobin were achieved in 12 (86%) and 2 (14%) patients, respectively. Seven patients (50%) were rechallenged with ICPis, and one (14%) developed recurrent AIHA. Clinical and laboratory features of ICPi-AIHA were similar in DAT positive and negative patients. ICPi-AIHA shares many clinical features with primary AIHA; however, a unique aspect of ICPi-AIHA is a high incidence of DAT negativity. Glucocorticoids are an effective first-line treatment in the majority of patients with ICPi-AIHA, and most patients who are rechallenged with an ICPi do not appear to develop recurrence of AIHA.

Immunotherapy for hepatocellular carcinoma patients: is it ready for prime time?

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy and the second most common cause of cancer death worldwide. Current treatment options for patients with intermediate and advanced HCC are limited, and there is an unmet need for novel therapeutic approaches. HCC is an attractive target for immunomodulation therapy, since it arises in an inflammatory milieu due to hepatitis B and C infections and cirrhosis. However, a major barrier to the development and success of immunotherapy in patients with HCC is the liver's inherent immunosuppressive function. Recent advances in the field of cancer immunology allowed further characterization of immune cell subsets and function, and created new opportunities for therapeutic modulation of the immune system. In this review, we present the different immune cell subsets involved in potential immune modulation of HCC, discuss their function and clinical relevance, review the variety of immune therapeutic agents currently under investigation in clinical trials, and outline future research directions.

Tremelimumab in combination with ablation in patients with advanced hepatocellular carcinoma.

BACKGROUND & AIMS: Tremelimumab is a fully human monoclonal antibody that binds to cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) on the surface of activated T lymphocytes. Ablative therapies induce a peripheral immune response which may enhance the effect of anti-CTLA4 treatment in patients with advanced hepatocellular carcinoma (HCC). This study aimed to demonstrate whether tremelimumab could be combined safely and feasibly with ablation. METHODS: Thirty-two patients with HCC were enrolled: male:female: 28:4; median age: 62 (range 36-76). Patients were given tremelimumab at two dose levels (3.5 and 10mg/kg i.v.) every 4weeks for 6 doses, followed by 3-monthly infusions until off-treatment criteria were met. On day 36, patients underwent subtotal radiofrequency ablation or chemoablation. Staging was performed by contrast-enhanced CT or MRI scan every 8weeks. RESULTS: No dose-limiting toxicities were encountered. The most common toxicity was pruritus. Of the 19 evaluable patients, five (26.3%; 95% CI: 9.1-51.2%) achieved a confirmed partial response. Twelve of 14 patients with quantifiable HCV experienced a marked reduction in viral load. Six-week tumor biopsies showed a clear increase in CD8+ T cells in patients showing a clinical benefit only. Six and 12-month probabilities of tumor progression free survival for this refractory HCC population were 57.1% and 33.1% respectively, with median time to tumor progression of 7.4months (95% CI 4.7 to 19.4months). Median overall survival was 12.3months (95% CI 9.3 to 15.4months). CONCLUSIONS: Tremelimumab in combination with tumor ablation is a potential new treatment for patients with advanced HCC, and leads to the accumulation of intratumoral CD8+ T cells. Positive clinical activity was seen, with a possible surrogate reduction in HCV viral load. LAY SUMMARY: Studies have shown that the killing of tumors by direct methods (known as ablation) can result in the immune system being activated or switched on. The immune system could potentially also recognize and kill the cancer that is left behind. There are new drugs available known as immune checkpoint inhibitors which could enhance this effect. Here, we test one of these drugs (tremelimumab) together with ablation. CLINICAL TRIAL NUMBER: ClinicalTrials.gov: NCT01853618.

Adjuvant Trametinib Delays the Outgrowth of Occult Pancreatic Cancer in a Mouse Model of Patient-Derived Liver Metastasis.

PURPOSE: Most patients with pancreatic ductal adenocarcinoma (PDAC) die within 5 years following resection plus adjuvant gemcitabine (Gem) from outgrowth of occult metastases. We hypothesized that inhibition of the KRAS pathway with the MEK inhibitor trametinib would inhibit the outgrowth of occult liver metastases in a preclinical model. METHODS: Liver metastases harvested from two patients with PDAC (Tumors 608, 366) were implanted orthotopically in mice. Tumor cell lines were derived and transduced with lentiviruses encoding luciferase and injected into spleens of mice generating microscopic liver metastases. Growth kinetics of liver metastases were measured with bioluminescent imaging and time-to-progression (TTP), progression-free survival (PFS), and overall survival (OS) were determined. RESULTS: Trametinib (0.3 mg/kg BID) significantly prolonged OS versus control (Tumor 608: 114 vs. 43 days, p < 0.001; Tumor 366: not reached vs. 167 days, p = 0.0488). In vivo target validation demonstrated trametinib significantly reduced phosphorylated-ERK and expression of the ERK-responsive gene DUSP6. In a randomized, preclinical trial, mice were randomized to: (1) control, (2) adjuvant Gem (100 mg/kg IP, Q3 days) × 7 days followed by surveillance, or (3) adjuvant Gem followed by trametinib. Sequential Gem-trametinib significantly decreased metastatic cell outgrowth and increased TTP and PFS. CONCLUSIONS: Treatment of mice bearing micrometastases with trametinib significantly delayed tumor outgrowth by effectively inhibiting KRAS-MEK-ERK signaling. In a randomized, preclinical, murine trial adjuvant sequential Gem followed by trametinib inhibited occult metastatic cell outgrowth in the liver and increased PFS versus adjuvant Gem alone. An adjuvant trial of sequential Gem-trametinib is being planned in patients with resected PDAC.