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.

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.

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.

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.

Earlier presentation and application of curative treatments in hepatocellular carcinoma.

UNLABELLED: The purpose of the study was to assess the use of curative therapies for hepatocellular carcinoma (HCC) in the population. HCC treatment patterns were examined in Surveillance, Epidemiology, and End Results (SEER) 18 registries (28% of U.S.). Joinpoint regression analyses were performed to assess 2000-2010 incidence trends by tumor size, count, and receipt of potentially curative treatments (transplantation, resection, and ablation). SEER-Medicare data enabled evaluation of treatment patterns including receipt of sorafenib or transarterial chemoembolization (TACE) by HCC-associated comorbidities. Diagnoses of tumors≤5.0 cm in diameter significantly increased during 2000-2010, surpassing diagnosis of larger tumors. Overall, 23% of cases received potentially curative treatment. Joinpoint models indicated incidence rates of treatment with curative intent increased 17.6% per year during 2000-2005, then declined by -2.9% per year during 2005-2010 (P<0.001). Among HCC cases with a single tumor≤5.0 cm and no extension beyond the liver, use of ablative therapy significantly increased during 2000-2010. Use of invasive surgery for single tumors, regardless of size, significantly increased during the initial years of the decade, then plateaued. The group most likely to receive curative treatment in the SEER-Medicare cases was patients with one, small tumor confined to the liver (657 of 1,597 cases, 41%), with no difference in treatment by hepatic comorbidity status (P=0.24). A higher proportion of cases with reported liver-associated comorbidities were, however, diagnosed with tumors≤5.0 cm in diameter (1,745 0f 2,464, 71%) compared to patients with no reported comorbidities (996 of 2,596, 38%, P<0.001). CONCLUSION: Although more HCC patients were diagnosed with early disease over time, the use of curative treatments in this patient group has recently plateaued. Efforts to identify and treat more eligible candidates for curative therapy could be beneficial.

The immunological and clinical effects of mutated ras peptide vaccine in combination with IL-2, GM-CSF, or both in patients with solid tumors.

BACKGROUND: Mutant Ras oncogenes produce proteins that are unique to cancer cells and represent attractive targets for vaccine therapy. We have shown previously that vaccinating cancer patients with mutant ras peptides is feasible and capable of inducing a specific immune response against the relevant mutant proteins. Here, we tested the mutant ras peptide vaccine administered in combination with low dose interleukin-2 (IL-2) or/and granulocyte-macrophage colony-stimulating factor (GM-CSF) in order to enhance the vaccine immune response. METHODS: 5000 µg of the corresponding mutant ras peptide was given subcutaneously (SQ) along with IL-2 (Arm A), GM-CSF (Arm B) or both (Arm C). IL-2 was given SQ at 6.0 million IU/m²/day starting at day 5, 5 days/week for 2 weeks. GM-CSF was given SQ in a dose of 100 µg/day one day prior to each ras peptide vaccination for 4 days. Vaccines were repeated every 5 weeks on arm A and C, and every 4 weeks on arm B, for a maximum of 15 cycles or until disease progression. RESULTS: We treated 53 advanced cancer patients (38 with colorectal, 11 with pancreatic, 1 with common bile duct and 3 with lung) on 3 different arms (16 on arm A, 18 on arm B, and 19 on arm C). The median progression free survival (PFS) and overall survival (OS) was 3.6 and 16.9 months, respectively, for all patients evaluable for clinical response (n = 48). There was no difference in PFS or OS between the three arms (P = 0.73 and 0.99, respectively). Most adverse events were grade 1-2 toxicities and resolved spontaneously. The vaccine induced an immune response to the relevant ras peptide in a total of 20 out of 37 evaluable patients (54%) by ELISPOT, proliferative assay, or both. While 92.3% of patients on arm B had a positive immune response, only 31% of patients on arm A and 36% of patients on arm C had positive immune responses (P = 0.003, Fisher's exact test). CONCLUSIONS: The reported data showed that IL-2 might have a negative effect on the specific immune response induced by the relevant mutant ras vaccine in patients with advanced cancer. This observation deserves further investigations. TRIAL REGISTRATION: NCI97C0141.

Pre-immature dendritic cells (PIDC) pulsed with HPV16 E6 or E7 peptide are capable of eliciting specific immune response in patients with advanced cervical cancer.

BACKGROUND: The protein products of the early genes E6 and E7 in high-risk HPV types 16 and 18 have been implicated in the oncogenic capability of these viruses. Therefore, these peptides represent attractive vaccine therapy targets. METHODS: Thirty-two patients with advanced cervical cancer (HPV16 or 18 positive) were treated with HPV16 E6 (18-26) (Arm A) or HPV16 E7 (12-20) peptide (Arm B) pulsed on PBMCs in order to illicit immune response against the relevant peptide on both arms. These PBMCs were cultured for a short time (48 hours only) and in the presence of GM- CSF, accordingly, they were identified as "Pre-Immature Dentritic Cells". RESULTS: 51Cr release assay and ELISPOT demonstrated evidence of specific immune response against the relevant peptide in 10/16 (63%) evaluable patients in arm A and 7/12 (58%) in arm B. HPV16 E6 was found to be homologous to HPV18 E6 in both vivo and vitro. The median overall survival (OS) and progression free survival (PFS) for the full cohort was 10.0 and 3.5 months, respectively. There were no RECIST responses in any patient. The majority of toxicities were grade I and II. CONCLUSIONS: We demonstrated the feasibility and ability of Pre-Immature Dentritic Cells pulsed with HPV16 E6 (18-26) or HPV16 E7 (12-20) to induce a specific immune response against the relevant peptide despite the advanced disease of the cervical cancer patients treated on this trial. We believe that this observation deserves further investigations.

PD-1 Blockade Induces Reactivation of Nonproductive T-Cell Responses Characterized by NF-κB Signaling in Patients with Pancreatic Cancer.

PURPOSE: Pancreatic ductal adenocarcinoma (PDAC) trials have evaluated CTLA-4 and/or PD-(L)1 blockade in patients with advanced disease in which bulky tumor burden and limited time to develop antitumor T cells may have contributed to poor clinical efficacy. Here, we evaluated peripheral blood and tumor T cells from patients with PDAC receiving neoadjuvant chemoradiation plus anti-PD-1 (pembrolizumab) versus chemoradiation alone. We analyzed whether PD-1 blockade successfully reactivated T cells in the blood and/or tumor to determine whether lack of clinical benefit could be explained by lack of reactivated T cells versus other factors. EXPERIMENTAL DESIGN: We used single-cell transcriptional profiling and TCR clonotype tracking to identify TCR clonotypes from blood that match clonotypes in the tumor. RESULTS: PD-1 blockade increases the flux of TCR clonotypes entering cell cycle and induces an IFNγ signature like that seen in patients with other GI malignancies who respond to PD-1 blockade. However, these reactivated T cells have a robust signature of NF-κB signaling not seen in cases of PD-1 antibody response. Among paired samples between blood and tumor, several of the newly cycling clonotypes matched activated T-cell clonotypes observed in the tumor. CONCLUSIONS: Cytotoxic T cells in the blood of patients with PDAC remain sensitive to reinvigoration by PD-1 blockade, and some have tumor-recognizing potential. Although these T cells proliferate and have a signature of IFN exposure, they also upregulate NF-κB signaling, which potentially counteracts the beneficial effects of anti-PD-1 reinvigoration and marks these T cells as non-productive contributors to antitumor immunity. See related commentary by Lander and DeNardo, p. 474.

A Phase 1 Trial of Trebananib, an Angiopoietin 1 and 2 Neutralizing Peptibody, Combined with Pembrolizumab in Patients with Advanced Ovarian and Colorectal Cancer.

Ovarian cancers and microsatellite stable (MSS) colorectal cancers (CRC) are insensitive to anti-PD1 immunotherapy, and new immunotherapeutic approaches are needed. Preclinical data suggests a relationship between immunotherapy resistance and elevated angiopoietin 2 levels. We performed a phase 1 dose-escalation study of pembrolizumab and the angiopoietin 1/2 inhibitor trebananib (NCT03239145). This multicenter trial enrolled patients with metastatic ovarian cancer or MSS CRC. Trebananib was administered intravenously weekly for 12 weeks with 200 mg intravenous pembrolizumab every 3 weeks. The toxicity profile of this combination was manageable, and the protocol-defined highest dose level (trebananib 30 mg/kg weekly plus pembrolizumab 200 mg every 3 weeks) was declared the maximum tolerated dose. The objective response rate for all patients was 7.3% (90% confidence interval: 2.5-15.9%). Three patients with MSS CRC had durable responses for ≥3 years. One responding patient's CRC harbored a POLE mutation. The other two responding patients had left-sided CRCs with no baseline liver metastases, and genomic analysis revealed that they both had KRAS wild-type, ERBB2 amplified tumors. After development of acquired resistance, biopsy of one patient's KRAS wild-type, ERBB2 amplified tumor showed a substantial decline in tumor-associated T cells and an increase in immunosuppressive intratumoral macrophages. Future studies are needed to carefully assess whether clinicogenomic features, such as lack of liver metastases, ERBB2 amplification, and left-sided tumors, can predict increased sensitivity to PD1 immunotherapy combinations.

Circulating KRAS G12D but not G12V is associated with survival in metastatic pancreatic ductal adenocarcinoma.

While high circulating tumor DNA (ctDNA) levels are associated with poor survival for multiple cancers, variant-specific differences in the association of ctDNA levels and survival have not been examined. Here we investigate KRAS ctDNA (ctKRAS) variant-specific associations with overall and progression-free survival (OS/PFS) in first-line metastatic pancreatic ductal adenocarcinoma (mPDAC) for patients receiving chemoimmunotherapy ("PRINCE", NCT03214250), and an independent cohort receiving standard of care (SOC) chemotherapy. For PRINCE, higher baseline plasma levels are associated with worse OS for ctKRAS G12D (log-rank p = 0.0010) but not G12V (p = 0.7101), even with adjustment for clinical covariates. Early, on-therapy clearance of G12D (p = 0.0002), but not G12V (p = 0.4058), strongly associates with OS for PRINCE. Similar results are obtained for the SOC cohort, and for PFS in both cohorts. These results suggest ctKRAS G12D but not G12V as a promising prognostic biomarker for mPDAC and that G12D clearance could also serve as an early biomarker of response.