Advanced glycation end product (AGE) targeting antibody SIWA318H is efficacious in preclinical models for pancreatic cancer.

SIWA318H is a novel monoclonal antibody that selectively targets an advanced glycation end product biomarker found in damaged/dysfunctional cells exhibiting (a) aerobic glycolysis, and (b) oxidative stress. Cells with this biomarker are dysfunctional and are associated with stresses and/or damages relating to aging, cancer and other disease processes. In this study, we evaluated the biological effects and antitumor activity of SIWA318H in preclinical models for pancreatic cancer. SIWA318H binds to pancreatic cancer cells and cancer-associated fibroblasts, as well as tumor xenografts derived from pancreatic cancer patients. Furthermore, SIWA318H induced significant antibody-dependent cell-mediated cytotoxicity (ADCC) against pancreatic cancer cells. In a humanized CD34+ NSG mouse xenograft model for pancreatic cancer, tumors in mice treated with SIWA318H grew significantly slower compared to those in control mice (p < 0.001). After 3 weeks of treatment with SIWA318H, the tumor growth was suppressed by 68.8% and 61.5% for the high and low dose regimens, respectively, when compared to the isotype antibody control (ANOVA p < 0.002). Moreover, a significant increase in complete remission (CR) rate was observed in mice receiving the high dose (60%, p < 0.04) or low dose (77.8%, p < 0.02) of SIWA318H treatment compared with control mice (6.7%). Immunohistochemical analyses of the tumor tissues showed a significant decrease in senescent cells in the tumor microenvironment of SIWA318H treated mice compared to that of control treated mice (p < 0.05). These results provide compelling evidence that SIWA318H is a promising novel therapeutic against pancreatic cancer.

Treatment Response in First-Line Metastatic Pancreatic Ductal Adenocarcinoma Is Stratified By a Composite Index of Tumor Proliferation and CD8 T-Cell Infiltration.

PURPOSE: Determinants of treatment outcomes to chemotherapy-based regimens in metastatic pancreatic ductal adenocarcinoma (PDA) remain ill-defined. Our aim was to examine tissue-based correlates of treatment response and resistance using matched baseline and on-treatment biopsies collected from patients with PDA treated in the first-line metastatic setting. EXPERIMENTAL DESIGN: Patients with treatment-naïve metastatic PDA were enrolled in a Phase II trial (NCT02077881) investigating gemcitabine plus nab-paclitaxel in combination with indoximod, an orally administered small-molecule inhibitor of the IDO pathway. Baseline and on-treatment biopsies (week 8) of metastatic lesions (88% liver) were collected from a cohort of responders (N = 8) and non-responders (N = 8) based on RECIST v1.1 and examined by multiplex IHC and mRNA sequencing. RESULTS: Treatment altered the transcriptional profile of metastatic lesions with a decrease in tumor cell proliferation independent of treatment response. The antiproliferative response was seen in both basal and classical PDA subtypes. PDA subtype was not associated with survival outcomes; instead, genes involved in immune activation distinguished responders from non-responders. Tumor response was associated with an increase in CD3+ and CD8+ T-cell infiltrates into metastatic lesions. A composite of decreased tumor proliferation in response to treatment and increased CD8 T-cell infiltration in metastatic lesions identified responders and associated with a favorable survival outcome. CONCLUSIONS: Our findings suggest that inhibiting cancer cell proliferation alone in PDA is insufficient to produce tumor responses and support a role for tumor-extrinsic mechanisms, such as CD8+ T cells, which combine with the cancer cell proliferation index to define treatment outcomes.

Phase II trial of the IDO pathway inhibitor indoximod plus pembrolizumab for the treatment of patients with advanced melanoma.

BACKGROUND: The indoleamine 2,3-dioxygenase (IDO) pathway is a key counter-regulatory mechanism that, in cancer, is exploited by tumors to evade antitumor immunity. Indoximod is a small-molecule IDO pathway inhibitor that reverses the immunosuppressive effects of low tryptophan (Trp) and high kynurenine (Kyn) that result from IDO activity. In this study, indoximod was used in combination with a checkpoint inhibitor (CPI) pembrolizumab for the treatment for advanced melanoma. METHODS: Patients with advanced melanoma were enrolled in a single-arm phase II clinical trial evaluating the addition of indoximod to standard of care CPI approved for melanoma. Investigators administered their choice of CPI including pembrolizumab (P), nivolumab (N), or ipilimumab (I). Indoximod was administered continuously (1200 mg orally two times per day), with concurrent CPI dosed per US Food and Drug Administration (FDA)-approved label. RESULTS: Between July 2014 and July 2017, 131 patients were enrolled. (P) was used more frequently (n=114, 87%) per investigator's choice. The efficacy evaluable population consisted of 89 patients from the phase II cohort with non-ocular melanoma who received indoximod combined with (P).The objective response rate (ORR) for the evaluable population was 51% with confirmed complete response of 20% and disease control rate of 70%. Median progression-free survival was 12.4 months (95% CI 6.4 to 24.9). The ORR for Programmed Death-Ligand 1 (PD-L1)-positive patients was 70% compared with 46% for PD-L1-negative patients. The combination was well tolerated, and side effects were similar to what was expected from single agent (P). CONCLUSION: In this study, the combination of indoximod and (P) was well tolerated and showed antitumor efficacy that is worth further evaluation in selected patients with advanced melanoma.

Effective treatment of preexisting melanoma with whole cell vaccines expressing alpha(1,3)-galactosyl epitopes.

The hyperacute immune response in humans is a potent mechanism of xenograft rejection mediated by complement-fixing natural antibodies recognizing alpha(1,3)-galactosyl epitopes (alphaGal) not present on human cells. We exploited this immune mechanism to create a whole cell cancer vaccine to treat melanoma tumors. B16 melanoma vaccines genetically engineered to express alphaGal epitopes (B16alphaGal) effectively treated preexisting s.c. and pulmonary alphaGal-negative melanoma (B16Null) tumors in the alpha(1,3)-galactosyltransferase knockout mouse model. T cells from mice vaccinated with B16alphaGal recognized B16Null melanoma cells measured by detection of intracellular tumor necrosis factor-alpha. We showed successful adoptive transfer of immunity to recipient mice bearing lung melanoma metastasis. Mice receiving lymphocytes from donors previously immunized with B16alphaGal had reduced pulmonary metastases. The transfer of lymphocytes from mice vaccinated with control vaccine had no effect in the pulmonary metastasis burden. This study unequivocally establishes for the first time efficacy in the treatment of preexisting melanoma tumors using whole cell vaccines expressing alphaGal epitopes. Vaccination with B16alphagal induced strong long-lasting cell-mediated antitumor immunity extended to B16Null. These data formed the basis for the testing of this therapeutic strategy in human clinical trials currently under way.

Pancreatic cancer: Update on immunotherapies and algenpantucel-L.

Pancreatic adenocarcinoma is notoriously lethal, and despite improvements in systemic chemotherapy approaches bringing survival rates for metastatic disease to almost 1 year, by 2030 it is expected to become the second leading cause of cancer death. Pancreatic cancer (PC) prognosis has been associated with both the presence of intratumoral helper and cytotoxic T lymphocytes, as well as humoral immune responses to tumor associated antigens like mesothelin. It is well described that the PC microenvironment is characterized by a fibroinflammatory and immunosuppressive stroma. On these premises several immune-targeted strategies have been developed to harness the adaptable immune system with a goal of improving survival with little toxicity. Cancer vaccines involve the administration of tumor-associated antigens with the goal of inducing an endogenous anti-tumor response. Among several strategies discussed, we will focus on the algenpantucel-L (HyperAcute™ Pancreas) immunotherapy. Algenpantucel-L is a whole cell immunotherapy consisting of irradiated allogeneic PC cells genetically engineered to express the murine enzyme α(1,3)-galactosyltransferase (αGT), which ultimately leads to hyperacute rejection with complement- and antibody-dependent cytotoxicity. While phase III data in the adjuvant treatment of pancreatic cancer are pending, phase II results have been encouraging, particularly for patients who demonstrated humoral immunologic responses. Novel strategies using immune checkpoint inhibitors, costimulatory antibodies, and combinations with cancer vaccines may overcome immunotolerance and improve treatment success.

Algenpantucel-L immunotherapy in pancreatic adenocarcinoma.

Pancreatic adenocarcinoma is the 4th leading cause of cancer death in the USA and the EU. A minority of patients presents with surgically resectable and potentially curable disease, but among these, 80% are destined to relapse and overall survival rates with adjuvant chemotherapy average 24 months. Immunotherapy is a promising therapeutic option and a potential paradigm shift in the treatment of patients with pancreatic cancer, and may be particularly effective when used early in the disease course to prevent metastatic spread. Algenpantucel-L (HyperAcute Pancreas, NewLink Genetics, Ames, IA, USA) is a whole-cell immunotherapy consisting of irradiated allogeneic pancreatic cancer cells genetically engineered to express the murine enzyme α-GT, which results in hyperacute rejection of the tumor cells with complement- and antibody-dependent cytotoxicity. Phase II clinical trial data has been encouraging, particularly for patients who demonstrated humoral immunologic responses. Here, we report preliminary results and biomarkers correlations with clinical activity of algenpantucel-L in pancreatic cancer.

High-efficiency lentiviral vector-mediated gene transfer into murine macrophages and activated splenic B lymphocytes.

The goal of the present report was to determine if lentiviral vectors could mediate gene transfer into murine terminally differentiated macrophages and mature B lymphocytes as a new strategy of gene delivery into professional antigen-presenting cells (APC). We demonstrated that nondividing tissue resident macrophages were efficiently transduced in vitro by lentiviral vectors. Gene transfer efficiencies of up to 90% were demonstrated using a green fluorescent protein (GFP) reporter gene-containing vector and expression was stable for the length of cell culture. Transduced macrophages were functionally competent, preserving their phagocytic activity, accessory cell function, interleukin (IL)-12 secretion, and nitric oxide (NO) production similar to control untransduced macrophages. Lentiviral vector mediated transduction of CD19(+) B cell blasts was demonstrated to be in the range of 60%-70% GFP-positive cells. These transduced cells retain the ability to upregulate CD80 and CD86 similar to control B cell cultures. In addition, we show that the human immunodeficiency virus type 1 (HIV-1) accessory proteins Nef, Vpr, Vif, and Vpu are not required for the transduction of both resident macrophages and activated B lymphoblasts. We conclude that HIV-1-based lentiviral vectors can mediate efficient gene transfer into primary murine macrophages and mature B lymphocytes.

Combination immunotherapy for high-risk resected and metastatic melanoma patients.

BACKGROUND: Patients with advanced melanoma have a poor outcome. We hypothesize that combination immunotherapy can synergistically activate host immunity to generate an effective treatment for patients with high-risk, resected stage 3, recurrent, refractory, or stage 4 melanoma. METHODS: We conducted a phase 2 clinical trial of HyperAcute Melanoma (HAM) vaccine (NLG-12036, NewLink Genetics) combined with pegylated interferon (Sylatron, Merck). Trial design consisted of a 12-week regimen with the initial 4 weekly treatments consisting of HAM alone (intradermally) followed by 8 additional treatments of HAM plus Sylatron (subcutaneously, 6 µg/kg). Trial endpoint outcomes include clinical response, overall safety, and correlative findings for observed antitumor effect. RESULTS: Our cohort consisted of 25 patients with a median age of 60. Twenty-one patients completed the trial and 4 stopped because of progressive disease (PD). According to the Response Evaluation Criteria in Solid Tumors, of the 16 stage 4 patients, 2 had a complete response (CR), 1 had stable disease, and 4 had no evidence of disease (NED) after resection. For stage 2/3 patients, 3 of 9 remained NED, and the 1 stage 2C patient had slow PD with a single site resected and is currently NED. The median overall survival time was 29 months, with 60% of the patients surviving for >1 year. Of the 25 patients, 12 (48%) are still alive. All evaluable patients (21/21) seroconverted, developing autoimmune antibodies. Four of 25 patients developed vitiligo, correlating with 2 CR patients and 2 NED patients. CONCLUSION: Combination immunotherapy with HAM plus Sylatron shows clinical efficacy with tumor regression and concomitant immune activation. Optimization of dosing schedules and therapeutic efficacy should be further explored to enhance the benefit of this promising immunotherapeutic approach.

Immunotherapy updates in pancreatic cancer: are we there yet?

Pancreatic cancer is a lethal disease and remains one of the most resistant cancers to traditional therapies. Historically, chemotherapy or radiotherapy did not provide meaningful survival benefit in advanced pancreatic cancer. Gemcitabine and recently FOLFIRINOX (5-flourouracil, leucovorin, oxaliplatin and irinotecan) have provided some limited survival advantage in advanced pancreatic cancer. Targeted agents in combination with gemcitabine had not shown significant improvement in the survival. Current therapies for pancreatic cancer have their limitations; thus, we are in dire need of newer treatment options. Immunotherapy in pancreatic cancer works by recruiting and activating T cells that recognize tumor-specific antigens which is a different mechanism compared with chemotherapy and radiotherapy. Preclinical models have shown that immunotherapy and targeted therapies like vascular endothelial growth factor and epidermal growth factor inhibitors work synergistically. Hence, new immunotherapy and targeted therapies represent a viable option for pancreatic cancer. In this article, we review the vaccine therapy for pancreatic cancer.

Cellular immunotherapy study of prostate cancer patients and resulting IgG responses to peptide epitopes predicted from prostate tumor-associated autoantigens.

The immunogenicity of a cellular immunotherapy using genetically modified vaccines to express α(1,3)galactosyl epitopes (αGal) was evaluated in advanced prostate cancer (PC) patients. In this dose escalation phase I study, we report safety, feasibility, and immunologic data of an immunotherapy composed of 2 human PC cell lines engineered to express αGal epitopes (HyperAcute-Prostate, HAP, NewLink Genetics). Eight patients received up to 12 biweekly vaccinations with HAP. Enrolled patients (aged range, 53-85 y) had American Joint Committee on Cancer stage IV, any T, any N, M1, Eastern Cooperative Oncology Group PS≤2, at least 1 prior hormonal treatment and <3 prior chemotherapies, adequate bone marrow and organ function, and albumin ≥3.0 g/dL. Serum IgG antibodies to synthetic peptides overexpressed in PC were determined by enzyme-linked immunosorbent assay. Results indicate that HAP immunotherapy induced humoral immune responses to autoantigens in 2 of 8 patients. These patients developed IgG antibody to multiple epitopes overexpressed in PC after immunization. These responding patients received higher doses of the immunotherapy suggesting a dose response. Two immunogenic proteins (prostate-specific membrane antigen, hepsin) belong to the extracellular molecules family participating in malignant cell invasion. Median overall survival for patients was 25.1 months with 1 patient surviving over 70 months with stable PSA and bone metastasis before expiring of other causes. Three of 8 patients showed PSA stabilization (>100 d). In conclusion, HAP immunotherapy induces IgG responses to epitopes from autoantigens overexpressed in PC suggesting dose-dependent effect. HAP represents a viable immunotherapy approach to induce immune responses against tumor cells and may provide clinical benefit with minimal toxicity.

Allogeneic melanoma vaccine expressing alphaGal epitopes induces antitumor immunity to autologous antigens in mice without signs of toxicity.

Owing to the absence of alphaGal epitopes in human cells and constant stimulation of the immune system by the symbiotic bacterial flora, humans develop high titers of natural antibodies against these epitopes. It has been demonstrated that syngeneic whole cell vaccines modified to express alphaGal epitopes could be used to generate a potent anticancer vaccine. In this study, we tested whether allogeneic whole cell cancer vaccines modified to express alphaGal epitopes would be effective for the treatment of murine melanoma. The alpha(1,3)galactosyltransferase (alphaGT) knockout mice (H-2) with preexisting subcutaneous and pulmonary tumors [alphaGal B16, H-2] received therapeutic vaccinations with S91M3alphaGal (H-2) whole cell allogeneic vaccines. These mice had better survival and reduced pulmonary metastasis burden compared with control mice treated with S91M3 vaccine cells. Vaccination with S91M3alphaGal-induced cytotoxic CD8 T cells recognizing the syngeneic alphaGal B16 tumors measured by adoptive transfer to recipients bearing pulmonary metastases. The presence of allo-antigens did not dominate the induction of immunity to "cryptic" tumor antigens and had helped in the generation of a more efficient vaccine to treat preexisting tumors when compared with classic autologous vaccines. Vaccination with allogeneic alphaGal vaccines did not induce signs of toxicity including changes in weight, hematology, chemistry, and histopathology of major perfused organs or autoimmunity in long-term murine models for breast, lung, and melanoma. This study established the safety and efficacy data of allogeneic alphaGal whole cell vaccines and constituted the basis for the initiation of human clinical trials to treat human malignancies.

Complete protection against melanoma in absence of autoimmune depigmentation after rejection of melanoma cells expressing alpha(1,3)galactosyl epitopes.

The major barrier for xenotransplantation in humans is the presence of alpha(1-3) Galactosyl epitopes (alphaGal) in xenogeneic tissue and the vast quantities of natural antibodies (Ab) produced by humans against this epitope. The binding of anti-alphaGal Ab to cells expressing alphaGal triggers a complement-mediated hyperacute rejection of target cells. The hyperacute rejection of whole cancer cells, modified to express alphaGal epitopes, could be exploited as a new cancer vaccine to treat human cancers. We tested this hypothesis in alphaGalactosyltransferase knockout (alphaGT KO) mice which, like humans, do not express alphaGal on their cell surfaces and can produce anti-alphaGal Ab. Forty-five percent of mice with preexisting anti-alphaGal Ab rejected alphaGal positive melanoma cells (B16alphaGal). These mice remained tumor-free for more than 90 days. The majority of control mice injected with B16Null, alphaGal negative cells succumbed to melanoma. The rejection of B16alphaGal induced strong long-lasting antitumor immunity against B16Null measured by the expansion of cytotoxic T lymphocytes. In addition, mice rejecting B16alphaGal were protected against melanoma since they survived a second rechallenge with B16Null. Protected mice developed antitumor immunity in the absence of autoimmune depigmentation (vitiligo). These results show that rejection of alphaGal positive melanoma cells can efficiently boost the immune response to other tumor associated antigens present in alphaGal negative melanoma cells. This study supports the concept of a novel anticancer vaccine to treat human malignancies.