CCR2/CCR5 inhibitor permits the radiation-induced effector T cell infiltration in pancreatic adenocarcinoma.

The resistance of pancreatic ductal adenocarcinoma (PDAC) to immune checkpoint inhibitors (ICIs) is attributed to the immune-quiescent and -suppressive tumor microenvironment (TME). We recently found that CCR2 and CCR5 were induced in PDAC following treatment with anti-PD-1 antibody (αPD-1); thus, we examined PDAC vaccine or radiation therapy (RT) as T cell priming mechanisms together with BMS-687681, a dual antagonist of CCR2 and CCR5 (CCR2/5i), in combination with αPD-1 as new treatment strategies. Using PDAC mouse models, we demonstrated that RT followed by αPD-1 and prolonged treatment with CCR2/5i conferred better antitumor efficacy than other combination treatments tested. The combination of RT + αPD-1 + CCR2/5i enhanced intratumoral effector and memory T cell infiltration but suppressed regulatory T cell, M2-like tumor-associated macrophage, and myeloid-derived suppressive cell infiltration. RNA sequencing showed that CCR2/5i partially inhibited RT-induced TLR2/4 and RAGE signaling, leading to decreased expression of immunosuppressive cytokines including CCL2/CCL5, but increased expression of effector T cell chemokines such as CCL17/CCL22. This study thus supports the clinical development of CCR2/5i in combination with RT and ICIs for PDAC treatment.

FDA Approval Summary: Nivolumab Plus Ipilimumab for the Treatment of Patients with Hepatocellular Carcinoma Previously Treated with Sorafenib.

On March 10, 2020, the U.S. Food and Drug Administration (FDA) granted accelerated approval to nivolumab in combination with ipilimumab for the treatment of patients with hepatocellular carcinoma (HCC) previously treated with sorafenib. The recommended approved dosage was nivolumab 1 mg/kg i.v. plus ipilimumab 3 mg/kg i.v. every 3 weeks for four cycles, followed by nivolumab 240 mg i.v. every 2 weeks. The approval was based on data from cohort 4 of CheckMate 040, which randomized patients with advanced unresectable or metastatic HCC previously treated with or who were intolerant to sorafenib to receive one of three different dosing regimens of nivolumab in combination with ipilimumab. Investigator-assessed overall response rate (ORR) was the primary endpoint, and ORR assessed by blinded independent central review (BICR) was an exploratory endpoint. BICR-assessed ORR and duration of response (DoR) form the primary basis of the FDA's regulatory decision, and BICR-assessed ORR was comparable in all three arms at 31%-32% with 95% confidence interval [CI] 18%-47%. The DoR ranged from 17.5 to 22.2 months across the three arms, with overlapping 95% CIs. Adverse events (AEs) were generally consistent with the known AE profiles of nivolumab and ipilimumab, and no new safety events were identified. This article summarizes the FDA review of the data supporting the approval of nivolumab and ipilimumab for the treatment of HCC. IMPLICATIONS FOR PRACTICE: Nivolumab and ipilimumab combination therapy is another option for patients with advanced hepatocellular carcinoma who experience radiographic progression during or after sorafenib or sorafenib intolerance. No new toxicities were identified, but, as expected, increased toxicity was observed with the addition of ipilimumab to nivolumab as compared with nivolumab alone, which is also approved for the same indication. Whether to administer nivolumab as a single agent or in combination with ipilimumab is expected to be a joint decision between the oncologist and patient, taking into consideration the potential for a higher likelihood of response and the potentially higher rate of toxicity with the combination.

Benefit-Risk Summary of Nivolumab for the Treatment of Patients with Unresectable Advanced, Recurrent, or Metastatic Esophageal Squamous Cell Carcinoma After Prior Fluoropyrimidine- and Platinum-Based Chemotherapy.

On June 10, 2020, the U.S. Food and Drug Administration (FDA) approved nivolumab (OPDIVO; Bristol Myers Squibb, New York, NY) for the treatment of patients with unresectable advanced, recurrent, or metastatic esophageal squamous cell carcinoma (ESCC) after prior fluoropyrimidine- and platinum-based chemotherapy. Approval was based on the results of a single, randomized, active-control study (ATTRACTION-3) that randomized patients to receive nivolumab or investigator's choice of taxane chemotherapy (docetaxel or paclitaxel). The study demonstrated a significant improvement in overall survival (OS; hazard ratio = 0.77; 95% confidence interval: 0.62-0.96; p = .0189) with an estimated median OS of 10.9 months in the nivolumab arm compared with 8.4 months in the chemotherapy arm. Overall, fewer patients in the nivolumab arm experienced treatment-emergent adverse events (TEAEs) of any grade, grade 3-4 TEAEs, and serious adverse events compared with the control arm. The safety profile of nivolumab in patients with ESCC was generally similar to the known safety profile of nivolumab in other cancer types with the following exception: esophageal fistula was identified as a new, clinically significant risk in patients with ESCC treated with nivolumab. Additionally, the incidence of pneumonitis was higher in the ESCC population than in patients with other cancer types who are treated with nivolumab. This article summarizes the FDA review of the data supporting the approval of nivolumab for the treatment of ESCC. IMPLICATIONS FOR PRACTICE: The approval of nivolumab for the treatment of adult patients with unresectable advanced, recurrent, or metastatic esophageal squamous cell carcinoma (ESCC) after prior fluoropyrimidine- and platinum-based chemotherapy was based on an overall survival (OS) benefit from a randomized, open-label, active-controlled study called ATTRACTION-3. Prior to this study, no drug or combination regimen had demonstrated an OS benefit in a randomized study for patients with ESCC after prior fluoropyrimidine- and platinum-based chemotherapy.

CD137 agonist-based combination immunotherapy enhances activated, effector memory T cells and prolongs survival in pancreatic adenocarcinoma.

Pancreatic ductal adenocarcinoma(PDAC) is resistant to the PD-1/PD-L1 blockade therapy. Previously, the combination of PD-1 blockade and vaccine therapy was shown to have a modest antitumor activity in murine models of PDAC. We used a murine syngeneic model of metastatic PDAC to identify, among multiple T cell modulators tested, which therapeutic agents in combination with the GVAX cancer vaccine and an anti-PD-1 antagonist antibody(αPD-1) are able to improve the survival. We found that an anti-CD137 agonist antibody(αCD137) most significantly improved survival in the mouse PDAC model. Moreover, αPD-1 and αCD137 together in combination with vaccine therapy more significantly increased the expression of costimulatory molecules CD137 and OX40 on CD4+PD-1+ and CD8+PD-1+ T cells comparing to αPD-1 or αCD137, respectively, suggesting that T cell activation within PDACs were enhanced by a synergy of αCD137 and αPD-1. On another hand, αCD137 treatment led to an increase in effector memory T cells independent of αPD-1. Although αCD137 does not increase the cytotoxic effector T cell function, the addition of αCD137 to GVAX+αPD-1 increased expression of IFNγ in EOMES + exhausted tumor-infiltrating T cells. Taken together, this preclinical study established the mechanism of targeting CD137 to enhance effector memory and activated T cells in PDAC. Immunohistochemistry analysis of resected human PDACs following the neo-adjuvant GVAX treatment showed increased levels of CD8+ T cells in those with high levels of CD137 expression, supporting an ongoing clinical trial of testing CD137 as a potential target in treating PDACs that are inflamed with T cells by vaccine therapy.

Interrogating the immune-modulating roles of radiation therapy for a rational combination with immune-checkpoint inhibitors in treating pancreatic cancer.

BACKGROUND: Radiation therapy (RT) has the potential to enhance the efficacy of immunotherapy, such as checkpoint inhibitors, which has dramatically altered the landscape of treatments for many cancers, but not yet for pancreatic ductal adenocarcinoma (PDAC). Our prior studies demonstrated that PD ligand-1 and indoleamine 2,3-dioxygenase 1 (IDO1) were induced on tumor epithelia of PDACs following neoadjuvant therapy including RT, suggesting RT may prime PDAC for PD-1 blockade antibody (αPD-1) or IDO1 inhibitor (IDO1i) treatments. In this study, we investigated the antitumor efficacy of the combination therapies with radiation and PD-1 blockade or IDO1 inhibition or both. METHODS: We developed and used a mouse syngeneic orthotopic model of PDAC suitable for hypofractionated RT experiments. RESULTS: The combination therapy of αPD-1 and RT improved survival. The dual combination of RT/IDO1i and triple combination of RT/αPD-1/IDO1i did not improve survival compared with RT/αPD-1, although all of these combinations offer similar local tumor control. RT/αPD-1 appeared to result in the best systemic interferon-γ response compared with other treatment groups and the highest local expression of immune-activation genes, including Cd28 and Icos. CONCLUSION: Our RT model allows examining the immune-modulatory effects of RT alone and in combination with immune-checkpoint inhibitors in the pancreas/local microenvironment. This study highlights the importance of choosing the appropriate immune-modulatory agents to be combined with RT to tip the balance toward antitumor adaptive immune responses.

Physical and chemical profiles of nanoparticles for lymphatic targeting.

Nanoparticles (NPs) have been gaining prominence as delivery vehicles for modulating immune responses to improve treatments against cancer and autoimmune diseases, enhancing tissue regeneration capacity, and potentiating vaccination efficacy. Various engineering approaches have been extensively explored to control the NP physical and chemical properties including particle size, shape, surface charge, hydrophobicity, rigidity and surface targeting ligands to modulate immune responses. This review examines a specific set of physical and chemical characteristics of NPs that enable efficient delivery targeted to secondary lymphoid tissues, specifically the lymph nodes and immune cells. A critical analysis of the structure-property-function relationship will facilitate further efforts to engineer new NPs with unique functionalities, identify novel utilities, and improve the clinical translation of NP formulations for immunotherapy.

Particulate carrier systems as adjuvants for cancer vaccines.

To overcome the immunosuppressive milieu of malignancy and lack of well-defined antigens, potent adjuvants are needed for cancer immunotherapy. Numerous small molecular immunomodulators have the potential to fulfill this role. To enhance the immune response and decrease the toxicity, particulate systems including nanoparticles and macroparticles have been increasingly proposed as carriers for cancer antigen and adjuvant delivery. These systems have the potential to co-deliver the antigens and adjuvants simultaneously in the same particle. In addition, the particles can be engineered for localized and targeted delivery, whether it be to the cellular or sub-cellular level. These properties limit systemic side effects and improve delivery efficiency, and thus enhance the vaccine's immune response. In particular, the particles can be constructed to mimic the size and surface patterns of microbes, organisms to which we have evolved a strong immune response. The release characteristics of the particles can likewise be controlled to simulate the body's response to infections. Boosting the immune response of vaccines by virtue of their intrinsic immunostimulatory properties, these particles can be dosing-sparing and have the potential to reduce production cost of vaccines. As the interest in personalized cancer vaccines increases with their encouraging outcomes in clinical trials, particulate carrier systems have the potential to play an important role in optimizing cancer vaccines.

Small molecule immunomodulation: the tumor microenvironment and overcoming immune escape.

Immunotherapy has led to a paradigm shift in the treatment of many advanced malignancies. Despite the success in treatment of tumors like non-small cell lung cancer (NSCLC) and melanoma, checkpoint inhibition-based immunotherapy has limitations. Many tumors, such as pancreatic cancer, are less responsive to checkpoint inhibitors, where patients tend to have a limited duration of benefit and where clinical responses are more robust in patients who are positive for predictive biomarkers. One of the critical factors that influence the efficacy of immunotherapy is the tumor microenvironment (TME), which contains a heterogeneous composition of immunosuppressive cells. Myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs) alter the immune landscape of the TME and serve as facilitators of tumor proliferation, metastatic growth and immunotherapy resistance. Small molecule inhibitors that target these components of the TME have been developed. This special issue review focuses on two promising classes of immunomodulatory small molecule inhibitors: colony stimulating factor-1 receptor (CSF-1R) and focal adhesion kinase (FAK). Small molecule inhibitors of CSF-1R reprogram the TME and TAMs, and lead to enhanced T-cell-mediated tumor eradication. FAK small molecule inhibitors decrease the infiltration MDSCs, TAMs and regulatory T-cells. Additionally, FAK inhibitors are implicated as modulators of stromal density and cancer stem cells, leading to a TME more conducive to an anti-tumor immune response. Immunomodulatory small molecule inhibitors present a unique opportunity to attenuate immune escape of tumors and potentiate the effectiveness of immunotherapy and traditional cytotoxic therapy.

Dissecting the Stromal Signaling and Regulation of Myeloid Cells and Memory Effector T Cells in Pancreatic Cancer.

PURPOSE: Myeloid cells are a prominent immunosuppressive component within the stroma of pancreatic ductal adenocarcinoma (PDAC). Previously, targeting myeloid cells has had limited success. Here, we sought to target the myeloid cells through modifying a specific stromal component. EXPERIMENTAL DESIGN: A murine model of metastatic PDAC treated with an irradiated whole-cell PDAC vaccine and PDAC specimens from patients treated with the same type of vaccine were used to assess the immune-modulating effect of stromal hyaluronan (HA) degradation by PEGPH20. RESULTS: Targeting stroma by degrading HA with PEGPH20 in combination with vaccine decreases CXCL12/CXCR4/CCR7 immunosuppressive signaling axis expression in cancer-associated fibroblasts, myeloid, and CD8+ T cells, respectively. This corresponds with increased CCR7- effector memory T-cell infiltration, an increase in tumor-specific IFNγ, and improved survival. In the stroma of human PDACs treated with the same vaccine, decreased stromal CXCR4 expression significantly correlated with decreased HA and increased cytotoxic activities, suggesting CXCR4 is an important therapeutic target. CONCLUSIONS: This study represents the first to dissect signaling cascades following PDAC stroma remodeling via HA depletion, suggesting this not only overcomes a physical barrier for immune cell trafficking, but alters myeloid function leading to downstream selective increases in effector memory T-cell infiltration and antitumor activity.

Adding combination immunotherapy consisting of cancer vaccine, anti-PD-1 and anti-CSF1R antibodies to gemcitabine improves anti-tumor efficacy in murine model of pancreatic ductal adenocarcinoma.

BACKGROUND: Immunotherapy can take advantage of the immunogenic response that chemotherapy elicits in tumors. Gemcitabine is a standard agent used in the treatment of pancreatic cancer, with known effects on the tumor immune microenvironment. The combination immunotherapy of the GVAX cancer vaccine, anti-PD-1 antibody and anti-CSF-1R antibody has been shown to improve survival in a murine model of metastatic pancreatic adenocarcinoma. This combination regimen also increased the infiltration of CD8+ T-cells that expressed both PD1 and CD137, and these T-cells were shown to express high levels of interferon-gamma, a marker of cytotoxic effector CD8+ T-cells. The effect of the addition of gemcitabine to this promising immunotherapy regimen has not been investigated. METHODS: Mice with liver-metastatic pancreatic adenocarcinoma were followed for 120 days to determine if adding immunotherapy, which comprised of varying combinations of GVAX, anti-PD-1 antibody and anti-CSF-1R antibody, to gemcitabine improved survival. Tumor-infiltrating CD8+ T-cells and myeloid cells, harvested after the mice were treated for 2 weeks, were analyzed with flow cytometry to characterize the effect the chemo-immunotherapy regimen had on the tumor microenvironment (TME). RESULTS: Adding combination immunotherapy after gemcitabine improved survival compared to gemcitabine treatment alone (gemcitabine/GVAX/anti-PD1, P<0.001; gemcitabine/anti-PD1/anti-CSF-1R, P<0.05; gemcitabine/GVAX/anti-PD1/anti-CSF-1R, P<0.01). However, there was no difference in survival between the three chemo-immunotherapy treatment regimens. Compared to gemcitabine-only treatment, the chemo-immunotherapy regimens also increased the percentage of tumor-infiltrating CD8+ T-cells that expressed interferon-gamma (gemcitabine/GVAX/anti-PD1, P<0.0001 and gemcitabine/GVAX/anti-PD1/anti-CSF-1R, P<0.0001). The chemo-immunotherapy regimens also increased the number of tumor-infiltrating PD1+CD137+CD8+ T-cells and interferon-gamma-expressing PD1+CD137+CD8+ T-cells, but these increases were not statistically significant. Anti-CSF-1R antibody decreased the infiltration of myeloid cells and myeloid-derived suppressor cells caused by GVAX (P<0.05), and trended towards decreasing tumor-associated macrophages (TAMs) (P=0.18). CONCLUSIONS: The addition of anti-PD1 antibody with GVAX and/or anti-CSF-1R antibody to gemcitabine improved the survival of mice with liver-metastatic pancreatic ductal adenocarcinoma (PDA). Gemcitabine with GVAX and anti-PD1 with or without anti-CSF-1R also improved the infiltration of effector CD8+ T-cells, and the presence of anti-CSF-1R in the chemo-immunotherapy regimens decreased the infiltration of myeloid cells. The overlapping mechanisms of the components in the chemo-immunotherapy regimens may explain the lack of survival difference between the various regimens, and this remains to be explored.

Targeting myeloid-inflamed tumor with anti-CSF-1R antibody expands CD137+ effector T-cells in the murine model of pancreatic cancer.

BACKGROUND: The pancreatic cancer vaccine, GVAX, induces novel lymphoid aggregates in the otherwise immune quiescent pancreatic ductal adenocarcinoma (PDAC). GVAX also upregulates the PD-1/PD-L1 pathway, and a pre-clinical model demonstrated the anti-tumor effects of combination GVAX and anti-PD-1 antibody therapy (GVAX/αPD-1). Resistance to GVAX was associated with an immune-suppressive myeloid cell infiltration, which may limit further therapeutic gains of GVAX/αPD-1 therapy. The expression of CSF-1R, a receptor important for myeloid cell migration, differentiation and survival, and the effect of its therapeutic blockade in the context of GVAX in PDAC has not been investigated. METHODS: Lymphoid aggregates appreciated in 24 surgically resected PDAC from patients who received one dose of neoadjuvant GVAX were analyzed with multiplex immunohistochemistry. Flow cytometry analysis of tumor infiltrating T-cells in a murine model of PDAC was performed to investigate the therapeutic effects and mechanism of anti-CSF-1R/anti-PD-1/GVAX combination immunotherapy. RESULTS: High CSF-1R expression in resected PDAC from patients who received neoadjuvant GVAX was associated with a higher myeloid to lymphoid cell ratio (p < 0.05), which has been associated with poorer survival. This higher CSF-1R expression was associated with a higher intra-tumoral infiltration of immature dendritic cells (p < 0.05), but not mature dendritic cells (p = 0.132). In the pre-clinical murine model, administering anti-CSF-1R antibody prior to and after GVAX/αPD-1 ("pre/post-αCSF-1R + αPD-1 + GVAX") enhanced the survival rate compared to GVAX/αPD-1 dual therapy (p = 0.005), but administering anti-CSF-1R only before GVAX/αPD-1 did not (p = 0.41). The "pre/post-αCSF-1R + αPD-1 + GVAX" group also had higher intra-tumoral infiltration of PD-1 + CD8+ and PD-1 + CD4+ T-cells compared to αPD-1/GVAX (p < 0.001). Furthermore, this regimen increased the intra-tumoral infiltration of PD-1 + CD137 + CD8+, PD-1 + CD137 + CD4+ and PD-1 + OX40 + CD4+ T-cells (p < 0.001). These PD-1 + CD137 + CD8+ T-cells expressed high levels of interferon-γ (median 80-90%) in response to stimulation with CD3/CD28 activation beads, and this expression was higher than that of PD-1 + CD137-CD8+ T-cells (p < 0.001). CONCLUSIONS: The conversion of exhausted PD-1+ T-cells to CD137+ activated effector T-cells may contribute to the anti-tumor effects of the anti-CSF-1R/anti-PD-1/GVAX combination therapy. Anti-CSF-1R antibody with anti-PD-1 antibody and GVAX have the potential be an effective therapeutic strategy for treatment of PDAC.

Current Standards of Chemotherapy for Pancreatic Cancer.

PURPOSE: Pancreatic cancer has a dismal prognosis due to the early development of systemic metastatic disease. Chemotherapeutic agents are the only systemic therapy that offers patients meaningful benefit. METHODS: This study reviewed the literature for recently published Phase III clinical trials whose results have guided the current standards of chemotherapy for pancreatic cancer. FINDINGS: Although combination chemotherapy regimens are shown to be superior to gemcitabine monotherapy for both metastatic pancreatic cancer and adjuvant chemotherapy after surgical resection, it should be recognized that all combination chemotherapy regimens offer only limited benefits. In addition, there is a paucity of clinical trials that directly compare the various combination chemotherapy regimens. IMPLICATIONS: With the advancement of systemic cancer treatment beyond chemotherapy, it is important to devote more investigation into better understanding the biology of these chemotherapy regimens, such that we combine them with targeted therapeutics and immunotherapeutics in a rational and scientific manner. For the current treatment of pancreatic cancer, the available chemotherapy regimens have shown modest but statistically significant improvements in survival. However, it is important to avoid cross-comparisons of trials and choose regimens based on patient characteristics and the side-effect profiles of the regimen.

A Size-Selective Intracellular Delivery Platform.

Identifying and separating a subpopulation of cells from a heterogeneous mixture are essential elements of biological research. Current approaches require detailed knowledge of unique cell surface properties of the target cell population. A method is described that exploits size differences of cells to facilitate selective intracellular delivery using a high throughput microfluidic device. Cells traversing a constriction within this device undergo a transient disruption of the cell membrane that allows for cytoplasmic delivery of cargo. Unique constriction widths allow for optimization of delivery to cells of different sizes. For example, a 4 µm wide constriction is effective for delivery of cargo to primary human T-cells that have an average diameter of 6.7 µm. In contrast, a 6 or 7 µm wide constriction is best for large pancreatic cancer cell lines BxPc3 (10.8 µm) and PANC-1 (12.3 µm). These small differences in cell diameter are sufficient to allow for selective delivery of cargo to pancreatic cancer cells within a heterogeneous mixture containing T-cells. The application of this approach is demonstrated by selectively delivering dextran-conjugated fluorophores to circulating tumor cells in patient blood allowing for their subsequent isolation and genomic characterization.