Regression Of Primary Tumor Research Articles

AGI-134: a fully synthetic \u03b1-Gal glycolipid that converts tumors into in situ autologous vaccines, induces anti-tumor immunity and is synergistic with an anti-PD-1 antibody in mouse melanoma models

BackgroundTreatments that generate T cell-mediated immunity to a patient’s unique neoantigens are the current holy grail of cancer immunotherapy. In particular, treatments that do not require cumbersome and individualized ex vivo processing or manufacturing processes are especially sought after. Here we report that AGI-134, a glycolipid-like small molecule, can be used for coating tumor cells with the xenoantigen Galα1-3Galβ1-4GlcNAc (α-Gal) in situ leading to opsonization with pre-existing natural anti-α-Gal antibodies (in short anti-Gal), which triggers immune cascades resulting in T cell mediated anti-tumor immunity.MethodsVarious immunological effects of coating tumor cells with α-Gal via AGI-134 in vitro were measured by flow cytometry: (1) opsonization with anti-Gal and complement, (2) antibody-dependent cell-mediated cytotoxicity (ADCC) by NK cells, and (3) phagocytosis and antigen cross-presentation by antigen presenting cells (APCs). A viability kit was used to test AGI-134 mediated complement dependent cytotoxicity (CDC) in cancer cells. The anti-tumoral activity of AGI-134 alone or in combination with an anti-programmed death-1 (anti-PD-1) antibody was tested in melanoma models in anti-Gal expressing galactosyltransferase knockout (α1,3GT−/−) mice. CDC and phagocytosis data were analyzed by one-way ANOVA, ADCC results by paired t-test, distal tumor growth by Mantel–Cox test, C5a data by Mann–Whitney test, and single tumor regression by repeated measures analysis.ResultsIn vitro, α-Gal labelling of tumor cells via AGI-134 incorporation into the cell membrane leads to anti-Gal binding and complement activation. Through the effects of complement and ADCC, tumor cells are lysed and tumor antigen uptake by APCs increased. Antigen associated with lysed cells is cross-presented by CD8α+ dendritic cells leading to activation of antigen-specific CD8+ T cells. In B16-F10 or JB/RH melanoma models in α1,3GT−/− mice, intratumoral AGI-134 administration leads to primary tumor regression and has a robust abscopal effect, i.e., it protects from the development of distal, uninjected lesions. Combinations of AGI-134 and anti-PD-1 antibody shows a synergistic benefit in protection from secondary tumor growth.ConclusionsWe have identified AGI-134 as an immunotherapeutic drug candidate, which could be an excellent combination partner for anti-PD-1 therapy, by facilitating tumor antigen processing and increasing the repertoire of tumor-specific T cells prior to anti-PD-1 treatment.

Transformable Nanoparticle‐Enabled Synergistic Elicitation and Promotion of Immunogenic Cell Death for Triple‐Negative Breast Cancer Immunotherapy

AbstractAlthough cisplatin‐based neoadjuvant chemotherapy is an efficient therapy approach for triple‐negative breast cancer (TNBC), it has dismal prognosis and modestly improved survival benefit. Here, a synergistic immunotherapy of TNBC premised on the elicitation and promotion of immunogenic cell death (ICD) response, through a transformable nanoparticle‐enabled approach for contemporaneous delivery of cisplatin, adjudin, and WKYMVm is reported. The nanoparticles can sequentially respond to matrix metalloproteinases‐2, pH, and glutathione to achieve structural transformation with the advantages of optimal size change, efficient drug delivery, and well‐controlled release. Cisplatin and adjudin can synergistically amplify reactive oxygen species (ROS) cascade and eventually increase the formation of hydrogen peroxide and downstream highly toxic ROS like •OH, which can elicit ICD response by mechanisms of endoplasmic reticulum stress, apoptotic cell death, and autophagy. WKYMVm can further promote anti‐TNBC immunity by activation of formyl peptide receptor 1 to build stable interactions between dendritic cells and dying cancer cells. Thus, the nanoparticles achieve significant primary tumor regression and pulmonary metastasis inhibition as well as a remarkable survival benefit, with boosting of the innate and adaptive anti‐TNBC immunity.

Synthetic bacterial cancer therapy

Cancer Some bacteria preferentially grow in tumors, because exclusion of immune cells and reduced oxygen favor their proliferation. This phenomenon offers the opportunity to exploit nonpathogenic engineered bacteria to deliver drugs directly into the tumor. Chowdhury et al. developed a synthetic Escherichia coli strain programmed to target the innate immune regulator CD47. A single-domain antibody fragment (nanobody) therapeutic loaded into the bacteria blocks CD47 and promotes antitumor responses. In mice, this treatment led to regression of both primary tumors and metastases. Bacterial delivery of the CD47 nanobody to tumors, combined with bacterial lysis, stimulates antitumor immune responses and immune memory, indicating that this could be a viable therapeutic approach. Nat. Med. 25 , 1057 (2019).

Abstract 3259: heterodimeric IL-15 monotherapy results in complete regression of EO771 murine breast tumors through cDC1-lymphocyte interactions and induction of antitumor immunity

Abstract Introduction: IL-15 is a cytokine important for the maintenance, proliferation and activation of lymphocytes, including CD8+ T and natural killer (NK) cells. The native form of IL-15 is a heterodimer either embedded in the plasma membrane or released in a soluble form. Several preclinical cancer models have supported the anti-tumor activity of heterodimeric IL-15, which is presently in clinical trials. We have produced heterodimeric IL-15 (hetIL-15) and also fusions to the Fc fragments (hetIL-15FC) of human, macaque or mouse antibodies. We assessed the effects of hetIL-15 monotherapy after systemic and locoregional administration in the proximity of EO771 orthotopically implanted breast tumors. Experimental procedures: We evaluated the therapeutic efficacy of hetIL-15 and hetIL-15FC immunotherapy in the murine EO771 triple negative breast cancer orthotopic model using both syngeneic C57BL/6 mice and RAG-1 immunodeficient mice. We monitored the effects of hetIL-15 treatment on Tumor Infiltrating Lymphocytes (TILs), lymphoid organs and blood by Flow cytometry and Immunohistochemisty (IHC). Using Seahorse technology, we also evaluated the metabolic profile of the CD8+ T cells, reflecting their activation status. Results: Monotherapy with hetIL-15FC peritumorally in the area of mammary pad resulted in complete tumor regression in half of the treated mice. hetIL-15 treatment resulted in an increased survival accompanied with decreased or completely eradicated metastatic disease, in C57BL/6 mice. Significant tumor delay was also observed after peritoneal injection of hetIL-15 in C57BL/6 as well as in RAG-1 mice with hetIL-15FC, but complete tumor regression was not achieved. hetIL-15FC peritumoral administration reshaped the tumor microenvironment and caused an increased infiltration of NK cells and CD8+ T cells with effector phenotype. Both cytotoxic T cells and NK were activated and proliferating, as shown by Flow, including Granzyme B and Ki67 staining. hetIL-15FC treatment resulted in increased tumor infiltration of both CD8+ and CD4+ T memory cells and provided strong protection to these mice against subsequent re-challenges with EO771 tumor. Furthermore, peritumoral hetIL-15FC administration resulted in an increase of intratumoral conventional Dendritic cells (cDC1), suggesting a mechanism for the intratumoral attraction of lymphocytes. Conclusion: Monotherapy with hetIL-15FC locoregional administration resulted in complete regression of EO771 primary breast cancer tumors, activating both cytotoxic arms of the immune system, and providing persisting protective immunity. Mechanism of function of hetIL-15 is through cDC1 and lymphocyte interactions that lead to the reciprocal attraction of cDC1 and activated cytotoxic lymphocytes into the tumors and the generation of long-term anti-tumor immunity. Citation Format: Dimitris Stellas, Sevasti Karaliota, Vasiliki Stravokefalou, Bethany A. Nagy, Barbara K. Felber, George N. Pavlakis. heterodimeric IL-15 monotherapy results in complete regression of EO771 murine breast tumors through cDC1-lymphocyte interactions and induction of antitumor immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3259.

Optical Imaging of Glucose Uptake and Mitochondrial Membrane Potential to Characterize Her2 Breast Tumor Metabolic Phenotypes.

With the large number of women diagnosed and treated for breast cancer each year, the importance of studying recurrence has become evident due to most deaths from breast cancer resulting from tumor recurrence following therapy. To mitigate this, cellular and molecular pathways used by residual disease prior to recurrence must be studied. An altered metabolism has long been considered a hallmark of cancer, and several recent studies have gone further to report metabolic dysfunction and alterations as key to understanding the underlying behavior of dormant and recurrent cancer cells. Our group has used two probes, 2-[N-(7-nitrobenz-2-oxa-1, 3-diaxol-4-yl) amino]-2-deoxyglucose (2-NBDG) and tetramethyl rhodamine ethyl ester (TMRE), to image glucose uptake and mitochondrial membrane potential, respectively, to report changes in metabolism between primary tumors, regression, residual disease, and after regrowth in genetically engineered mouse (GEM)-derived mammospheres. Imaging revealed unique metabolic phenotypes across the stages of tumor development. Although primary mammospheres overexpressing Her2 maintained increased glucose uptake ("Warburg effect"), after Her2 downregulation, during regression and residual disease, mammospheres appeared to switch to oxidative phosphorylation. Interestingly, in mammospheres where Her2 overexpression was turned back on to model recurrence, glucose uptake was lowest, indicating a potential change in substrate preference following the reactivation of Her2, reeliciting growth. Our findings highlight the importance of imaging metabolic adaptions to gain insight into the fundamental behaviors of residual and recurrent disease. IMPLICATIONS: This study demonstrates these functional fluorescent probes' ability to report metabolic adaptations during primary tumor growth, regression, residual disease, and regrowth in Her2 breast tumors.

Abstract LB-202: Immunotherapy with TMV vaccine inhibits metastatic tumor growth in an immune checkpoint resistant murine lung cancer model

Abstract Lung cancer is the second most common cancer among men and women and the leading cause of cancer deaths in the world. Despite the advancements in diagnostic technologies and the development of novel treatments in the recent years such as immune checkpoint inhibitor (ICI) therapy, the prognosis of lung cancer patients is still poor, and the survival rate is low. The patient-to-patient heterogeneity is the major problem in treating lung cancer, which results in differential responses to ICI therapy. In this study, we investigated the efficacy of a vaccine immunotherapy prepared by modification of tumor membrane vesicles (TMVs) prepared from the tumors to express immunostimulatory molecules in combination with ICI therapy in a partially ICI resistant murine lung cancer model. We demonstrate that prophylactic vaccination of TMV adjuvanted with immunostimulatory molecules prevents the CMT-167 tumor growth in mice and helps the mice develop immunological memory to the tumor cell challenge. In a therapeutic setting, the TMV vaccine inhibited tumor growth and induced primary tumor regression in 40% of mice and significantly reduced the metastatic tumor burden. However, the combination of TMV vaccination with anti-PD-1 mAb doesn’t have a synergistic or additive effect on the primary or metastatic tumor growth. Overall, these studies provide insight into using the TMV vaccine immunotherapy for treating lung cancer. Funding: Supported by the Lung Cancer seed grant from the Winship Cancer Institute of Emory University Citation Format: Lei Huang, Dr. Selvaraj's lab. Immunotherapy with TMV vaccine inhibits metastatic tumor growth in an immune checkpoint resistant murine lung cancer model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-202.

Immunotherapy with tumor membrane vesicle-based cancer vaccine inhibits metastatic tumor growth in lung cancer model

Abstract Lung cancer is the leading cause of cancer related deaths accounting for approximately 30% of all cancer related mortalities affecting both men and women. Currently, there is no cure for the common non-small cell lung cancer (NSCLC) thus development of efficacious therapies is urgently needed. In this study, we investigate the efficacy of tumor membrane-based vaccine immunotherapy and immune checkpoint blockade antibodies lung cancer models LL/2 and CMT-167 models. LL/2 and CMT-167 tumor tissues were harvested from C57BL/6 mice and processed to generate tumor membrane vesicles (TMVs). TMVs were then modified with immunostimulatory molecules and used for immunization. Tumor growth was monitored every 3 days. Survival was assessed using a Kaplan-Meier survival curve and significance determined using a Log-rank test for comparison analysis. Metastasis of CMT-167 was assessed by clonogenic assay. TMV vaccine alone, or in combination, anti-PD-1 or anti-CTLA-4 antibodies neither decreased the tumor growth nor improved the survival of mice challenged with LL/2 tumor cells. The prophylactic vaccination of TMV vaccine prevents the CMT-167 tumor growth in mice and helps the mice develop immunological memory to the tumor cell challenge. In a therapeutic setting, the TMV vaccine inhibited tumor growth and induced primary tumor regression in 40% of mice and significantly reduced the metastatic tumor burden. Anti-tumor immunity induced by TMV vaccine requires CD4+ and NK cells albeit to a lesser extent but not CD8+ T cells for controlling the tumor growth. These models provide a valuable tool in analyzing the mechanism of interaction of immune cells with tumors that lead to either tumor regression or resistance to immunotherapies.

Primary tumor regression patterns in esophageal squamous cell cancer treated with definitive chemoradiotherapy and implications for surveillance schemes.

Purpose: The primary tumor regression patterns of patients with esophageal squamous cell carcinoma (ESCC) treated with definitive chemoradiotherapy (CRT) were investigated to determine an optimal surveillance scheme.Method: The clinical data and radiology images of patients before CRT, at completion of CRT and every 1–3 months for the subsequent 12 months or until disease progression were retrospectively reviewed to define the patterns of primary tumor regression after CRT. Survival rates were analyzed statistically in order to determine an optimal surveillance scheme.Results: A total of 82 patients were enrolled in the present study for analysis. At the first surveillance visit date at the end of CRT, a total of 21 patients achieved complete response (early-CR), 29 patients reached incomplete response (IR), 25 patients maintained stable disease (SD) and 7 patients encountered progression of disease (PD). During subsequent surveillance, a total of 14 IR patients regressed continuously to CR (later-CR), 15 patients maintained IR (early-IR) and 9 SD patients gradually regressed to IR (later-IR). At full tumor regression (FTR), a total of 21, 14, 15, 9, 16 and 7 patients were defined as early-CR, later-CR, early-IR, later-IR, SD and PD, respectively. The median FTR time for later-CR and later-IR was 7.5 and 7 weeks, respectively. The 3-year overall survival rate of the early-CR group was 85.7% (P<0.001), which was higher compared with the later-CR (16.7%), early-IR (20%), later-IR (11.1%), SD (6.3%) and PD (0%) groups.Conclusion: The early-CR following CRT is a robust prognostic predictor in patients with ESCC. To optimize the determination of tumor regression, ≥7 weeks after CRT is an optimal initial surveillance visit date. The surveillance of non-CR patients should concentrate on symptoms, nutrition and psychosocial support, rather than screening for recurrence of the disease.

Complete regression of primary melanoma associated with nevi involution under BRAF inhibitors: A case report and review of the literature.

Melanoma is one of the most immunogenic tumors among human neoplasms, with numerous clinical observations of partial or completely regressed tumors. It is an aggressive tumor, with the greatest reported number of somatic mutations, BRAF mutation being the most common one. BRAF mutation is also present in a higher percentage in benign nevi. Complete regression of primary tumor and involution of nevi are, however, rare phenomenon in melanoma that can appear in relation with UV exposure, surgical trauma, target therapy in melanoma, pregnancy or host immune response to an evolving melanoma tumor. We present the case of a 58-year-old man with a completely regressed metastatic melanoma who developed a second melanoma with concomitant involution of papillomatous nevi under BRAF inhibitors treatment. In reviewed literature we have found 53 cases of completely regressed primary melanomas, neither of them reporting nevi involution. Complete regression of primary tumor can occur as an immune response to tumor progression. Nevi can involute under BRAF inhibitor therapy, but development of new malignant lesions under BRAF inhibitors is linked to BRAF wild-type. Documentation of primary tumor and dynamic changes in nevi highlight the need of a good clinical skin examination and increase the utility of baseline and sequential dermoscopy in melanoma.

Liposomal Irinotecan Achieves Significant Survival and Tumor Burden Control in a Triple Negative Breast Cancer Model of Spontaneous Metastasis.

Triple negative breast cancer (TNBC) represents a significant therapeutic challenge due to its highly aggressive nature and lack of effective treatment options. Liposomal irinotecan (nal-IRI, ONIVYDE) was approved in 2015 (by the Food and Drug Administration, European Medicines Agency, and Therapeutic Goods Administration) and is a topoisomerase inhibitor indicated, in combination with fluorouracil and leucovorin, for the treatment of patients with metastatic adenocarcinoma of the pancreas after disease progression following gemcitabine-based therapy. This study investigates the potential therapeutic benefit of nal-IRI for the treatment of advanced TNBC in a clinically relevant mouse model of spontaneous metastasis (LM2-4). Female SCID mice were orthotopically inoculated with TNBC LM2-4-luc cells in the lower mammary fat pad. Following primary tumor resection, bioluminescence imaging (BLI) was used to monitor both metastasis formation and spread as well as response to treatment with nal-IRI. Weekly treatment with 10 mg/kg of nal-IRI provided a 4.9-times longer median survival compared to both 50 mg/kg irinotecan treated and untreated animals. The survival benefit was supported by a significant delay in the regrowth of the primary tumor, effective control, and eventual regression of metastases assessed using longitudinal BLI, which was confirmed at the study end point with magnetic resonance (MR) imaging and post-mortem observation. This preclinical investigation demonstrates that, at a five-times lower dose compared to the free drug, liposomal irinotecan provides significant survival benefit and effective management of metastatic disease burden in a clinically relevant model of spontaneous TNBC metastases. These findings support the evaluation of nal-IRI in patients with advanced and metastatic TNBC.

Traceable Bioinspired Nanoparticle for the Treatment of Metastatic Breast Cancer via NIR-Trigged Intracellular Delivery of Methylene Blue and Cisplatin.

Cytotoxic T lymphocyte (CTL) eliminates abnormal cells through target recognition-triggered intracellular toxin delivery. Chimeric antigen receptor T-cell improves cancer cell recognition of CTL, but its effectiveness and safety in solid tumor treatment are still hampered by poor tumor infiltration, suppressive tumor microenvironment, and severe on-target off-tumor toxicity. Given the functionality and challenges of CTL in cancer therapy, herein, a CTL-inspired nanovesicle (MPV) with a cell membrane-derived shell and a methylene blue (MB) and cisplatin (Pt) loaded gelatin nanogel core is created. The MPV generates contrast for tumor photoacoustic imaging, and produces hyperthermia upon laser irradiation, enabling photothermal imaging and deep tumor penetration. Meanwhile, it releases MB and Pt, and then delivers them into the cytosol of cancer cells, which process can be visualized by imaging the recovery of MB-derived fluorescence. The localized hyperthermia, photodynamic therapy, and chemotherapy together kill 4T1 breast cancer cells effectively, resulting in primary tumor regression and 97% inhibition of pulmonary metastasis, without significant toxicity to the animals. Taken together, the MPV shows tumor-specific and stimuli-triggered intracellular toxin delivery with advantages in traceable accumulation and activation, high tumor penetration, and triple combination therapy, and thus can be an effective nanomedicine for combating metastatic breast cancer.

P-306 - The relationship between primary tumor regression grade and lymph nodes status in local advanced rectal cancer after neoadjuvant chemoradiation therapy

P-306 - The relationship between primary tumor regression grade and lymph nodes status in local advanced rectal cancer after neoadjuvant chemoradiation therapy

Immune Response in Melanoma: A Basis to Understand the Role of Immunotherapy with Immune Checkpoint Inhibitors

The knowledge of the pathophysiology of tumour progression is crucial to understand the therapeutic targets in order to control the disease. The mechanisms used by the immune system to affect cancer development and progression has been a challenging question in immunology. It is now postulated that immunology plays a dual role in this process: it protects against tumour growth, destroying “aberrant” tumour cells, but may also promote tumour progression by selecting tumour cells that are able to escape the immune response and survive in an immunocompetent host. These findings gave rise to the concept of “cancer immunoediting”, which explains the influence of the immune system on tumour progression. Several observations like immunosuppression as a risk factor for melanoma, the possibility of partial or complete regression of primary tumour and development of vitiligo, have suggested that melanoma is an immunogenic tumour but a successful tumour evolution can occur in the light of the “immunoediting” concept. Immune checkpoints, cytotoxic T lymphocyte antigen (CTLA)-4 and programmed cell death (PD-1), were recognized to have important roles in regulating T cell responses during tumour development and were proven to be effective targets in treating advanced melanoma. This article will briefly review the process of tumour evolution and its interaction with the immune system as well as the mechanism of action of the immune checkpoint inhibitors to understand better the new targeted immunotherapies for advanced melanoma, that will be further discussed.

Prognostic value of pathological lymph node status and primary tumour regression grading following neoadjuvant chemotherapy - results from the MRC OE02 oesophageal cancer trial.

AimsNeoadjuvant chemotherapy (NAC) remains an important therapeutic option for advanced oesophageal cancer (OC). Pathological tumour regression grade (TRG) may offer additional information by directing adjuvant treatment and/or follow‐up but its clinical value remains unclear. We analysed the prognostic value of TRG and associated pathological factors in OC patients enrolled in the Medical Research Council (MRC) OE02 trial.Methods and resultsHistopathology was reviewed in 497 resections from OE02 trial participants randomised to surgery (S group; n = 244) or NAC followed by surgery [chemotherapy plus surgery (CS) group; n = 253]. The association between TRG groups [responders (TRG1–3) versus non‐responders (TRG4–5)], pathological lymph node (LN) status and overall survival (OS) was analysed. One hundred and ninety‐five of 253 (77%) CS patients were classified as ‘non‐responders’, with a significantly higher mortality risk compared to responders [hazard ratio (HR) = 1.53, 95% confidence interval (CI) = 1.05–2.24, P = 0.026]. OS was significantly better in patients without LN metastases irrespective of TRG [non‐responders HR = 1.87, 95% CI = 1.33–2.63, P < 0.001 versus responders HR = 2.21, 95% CI = 1.11–4.10, P = 0.024]. In multivariate analyses, LN status was the only independent factor predictive of OS in CS patients (HR = 1.93, 95% CI = 1.42–2.62, P < 0.001). Exploratory subgroup analyses excluding radiotherapy‐exposed patients (n = 48) showed similar prognostic outcomes.ConclusionLymph node status post‐NAC is the most important prognostic factor in patients with resectable oesophageal cancer, irrespective of TRG. Potential clinical implications, e.g. adjuvant treatment or intensified follow‐up, reinforce the importance of LN dissection for staging and prognostication.

Antitumor Properties of RAF709, a Highly Selective and Potent Inhibitor of RAF Kinase Dimers, in Tumors Driven by Mutant RAS or BRAF.

Resistance to the RAF inhibitor vemurafenib arises commonly in melanomas driven by the activated BRAF oncogene. Here, we report antitumor properties of RAF709, a novel ATP-competitive kinase inhibitor with high potency and selectivity against RAF kinases. RAF709 exhibited a mode of RAF inhibition distinct from RAF monomer inhibitors such as vemurafenib, showing equal activity against both RAF monomers and dimers. As a result, RAF709 inhibited MAPK signaling activity in tumor models harboring either BRAFV600 alterations or mutant N- and KRAS-driven signaling, with minimal paradoxical activation of wild-type RAF. In cell lines and murine xenograft models, RAF709 demonstrated selective antitumor activity in tumor cells harboring BRAF or RAS mutations compared with cells with wild-type BRAF and RAS genes. RAF709 demonstrated a direct pharmacokinetic/pharmacodynamic relationship in in vivo tumor models harboring KRAS mutation. Furthermore, RAF709 elicited regression of primary human tumor-derived xenograft models with BRAF, NRAS, or KRAS mutations with excellent tolerability. Our results support further development of inhibitors like RAF709, which represents a next-generation RAF inhibitor with unique biochemical and cellular properties that enables antitumor activities in RAS-mutant tumors.Significance: In an effort to develop RAF inhibitors with the appropriate pharmacological properties to treat RAS mutant tumors, RAF709, a compound with potency, selectivity, and in vivo properties, was developed that will allow preclinical therapeutic hypothesis testing, but also provide an excellent probe to further unravel the complexities of RAF kinase signaling. Cancer Res; 78(6); 1537-48. ©2018 AACR.

Systemic Antitumor Immunity by PD-1/PD-L1 Inhibition Is Potentiated by Vascular-Targeted Photodynamic Therapy of Primary Tumors.

Purpose: PD-1/PD-L1 pathway inhibition is effective against advanced renal cell carcinoma, although results are variable and may depend on host factors, including the tumor microenvironment. Vascular-targeted photodynamic (VTP) therapy with the photosensitizer WST11 induces a defined local immune response, and we sought to determine whether this could potentiate the local and systemic antitumor response to PD-1 pathway inhibition.Experimental Design: Using an orthotopic Renca murine model of renal cell carcinoma that develops lung metastases, we treated primary renal tumors with either VTP alone, PD-1/PD-L1 antagonistic antibodies alone, or a combination of VTP and antibodies and then examined treatment responses, including immune infiltration in primary and metastatic sites. Modulation of PD-L1 expression by VTP in human xenograft tumors was also assessed.Results: Treatment of renal tumors with VTP in combination with systemic PD-1/PD-L1 pathway inhibition, but neither treatment alone, resulted in regression of primary tumors, prevented growth of lung metastases, and prolonged survival in a preclinical mouse model. Analysis of tumor-infiltrating lymphocytes revealed that treatment effect was associated with increased CD8+:regulatory T cell (Treg) and CD4+FoxP3-:Treg ratios in primary renal tumors and increased T-cell infiltration in sites of lung metastasis. Furthermore, PD-L1 expression is induced following VTP treatment of human renal cell carcinoma xenografts.Conclusions: Our results demonstrate a role for local immune modulation with VTP in combination with PD-1/PD-L1 pathway inhibition for generation of potent local and systemic antitumor responses. This combined modality strategy may be an effective therapy in cancers resistant to PD-1/PD-L1 pathway inhibition alone. Clin Cancer Res; 24(3); 592-9. ©2017 AACR.

Does total regression of primary rectal cancer after preoperative chemoradiotherapy represent "no tumor" status?

PurposeInsistence that total regression of primary tumor would not represent long-term oncologic outcomes has been raised. Therefore, this study aimed to evaluate the outcomes of these patients after preoperative chemoradiotherapy (PCRT) and radical surgery and to evaluate the associated risk factors.MethodsWe included 189 patients with rectal cancer who showed total regression of the primary tumor after PCRT, followed by radical resection, between 2001 and 2012. Recurrence-free survival (RFS) was calculated using the Kaplan-Meier method, and the results were compared with 77 patients with Tis rectal cancer who received only radical resection. Factors associated with RFS were evaluated using Cox regression analysis.ResultsSphincter-saving resection was performed for 146 patients (77.2%). Adjuvant chemotherapy was administered to 168 patients (88.9%). During the follow-up period, recurrence occurred in 17 patients (9%). The 5-year RFS was 91.3%, which was significantly lower than that of patients with Tis rectal cancer without PCRT (P = 0.005). In univariate analysis, preoperative CEA and histologic differentiation were associated with RFS. However, no factors were found to be associated with RFS.ConclusionRFS was lower in patients with total regression of primary rectal cancer after PCRT than in those with Tis rectal cancer without PCRT, and it would not be considered as the same entity with early rectal cancer or “disappeared tumor” status.

Local excision of scars after a complete clinical response to neoadjuvant CRT in rectal cancer—organ-preservation without function-preservation?

Management of rectal cancer has changed significantly over the last few decades (1). First, appropriateness of surgical technique with standardization of total mesorectal excision led to a substantial decrease in local recurrence rates (2). Second, the role of neoadjuvant chemoradiotherapy (nCRT) in further decreasing local failures after TME is currently well established (3). Finally, with optimal local disease control, the concept of organ-preservation has become an attractive alternative to patients with significant primary tumor regression after nCRT.

Primary and Nodal Tumor Regression Rates: Towards CT-Based 3D Volumetric Characterization of Response to Induction Chemotherapy in Oropharynx Cancer patients

Primary and Nodal Tumor Regression Rates: Towards CT-Based 3D Volumetric Characterization of Response to Induction Chemotherapy in Oropharynx Cancer patients

Hypofractionated Radiation Therapy Induces an Immune-Mediated Abscopal Effect When Combined with Anti-PD-1 Antibody

Anti tumor check-point immunotherapy could be synergized with local RT.However, various fraction regimens may lead to different immune response.In this study, we tested the immune response under different RT fraction regimens and chose the best fraction regimen to combine with anti-PD-1 immunotherapy. 4T1 murine breast tumor cells were implanted on left and right thigh of BALB/C mice as primary and secondary tumor. Five different fraction SBRT(24Gy×1,8Gy×3,8Gy×1-2Gy×8 or 2Gy×12f) were delivered on primary tumor.Immune response was detected in bilateral tumors, bilateral regional drainage lymph nodes, and spleen, including CD4+T cells, CD8+T cells, CD8+IFN-γ+T cells, and myeloid-derived suppressor cell (MDSC). Then, the best fraction regimen RT was chosen to combine with human anti-PD-1 mAb(HR301210),on humanPD-1 gene knocked-in mice. Relative local and systematic immune response was also detected. No obvious abscopal effect was observed under different fraction RT alone. Though each of the RT regimens achieved growth delay of the irradiated tumor but not the contralateral tumor, we found 24Gy×1 and 8Gy×3 fraction regimens delayed the primary tumor growth more evident than 8Gy×1-2Gy×8 and 2Gy×12f fraction regimens(P＜0.05 and P＜0.05). Hypofractionated radiotherapy(HRT) regimens including 24Gy×1 and 8Gy×3 achieved significantly higher CD8+ tumor infiltrating lymphocytes (TILs)(P＜0.001 and P＜0.05) in bilateral tumors, higher CD4+TILs (P＜0.001 and P＜0.001) in regional drainage lymph nodes of the primary tumor,higher CD4+T cells(P>0.05 and P＜0.05) and CD8 + IFN-γ + T cells (P>0.05 and P>0.05) in the spleen, and lower MDSC (P＜0.001and P＜0.001) in the spleenon 5 days after RT. However, the tendency of immune response stimulation at 48 hours RT was not as obvious as 5 days after RT. We only found CD4+T cells in regional drainage lymph nodes of the primary tumor were evidently higher of all RT groups than control group. In the next study, on day 20 after MC38 colorectal cancer cells injection, we observed primary tumor regression（P＜0.001) and remarkable contralateral tumor regression（P＜0.001)outside the radiation field in 8Gy×3 combined with PD-1-blocking mAb group, the so-called abscopal effect, whichnot occurred in other three groups.So far, we observed that different treatment regimens lead to different immune response. In systemic immune response, compared with single RT or single IT, RT combined with IT increased CD4+T cells（P＜0.05) and CD8+T cells（P＜0.05), decreased MDSC（P＜0.05) in spleen.In local immune response, the tendancy was not as obvious as systemic immune response.More detailed results from ongoing works remain to be further analyzed. Antitumor immune response could be activated by HRTbetter than CRT, which were mostly mediated by CD4+, CD8+T cells and MDSCs.Evident abscopal effect was found after combining SBRT withanti-PD-1 mAb.