TPS4267 Background: Locally advanced pancreatic ductal adenocarcinoma (LA-PDAC) with > 180° vascular encasement of major abdominal arteries is considered unresectable and is associated with poor prognosis. Standard-of-care options, including chemotherapy and chemoradiation, achieve limited conversion to resectability with high recurrence rates. Thus, a therapeutic approach that can effectively downstage LA-PDAC to resection is clinically needed. Activation of vascular-targeted photodynamic therapy (VTP) by Padeliporfin illumination at 753nm results in photochemical generation of oxygen and nitric oxide radicals that cause rapid occlusion followed by break down of the tumor vasculature, tumor necrosis and break-down of the extracellular matrix. Photosensitivity at > 6 hours is avoided due to 1.19 hours Padeliporfin half-life without accumulation in epithelial tissue. Padeliporfin-VTP activation by intra-arterial (IA) illumination has the potential to selectively ablate tumor tissue encasing the artery, reducing vascular encasement and enabling subsequent surgical resection. Robust feasibility and safety preclinical studies in normal swine and efficacy in mouse tumor models have demonstrated feasibility of light transmission through the arterial wall at a dose sufficient to induce tumor ablation at the artery interface and acceptable safety profile, supporting clinical translation. Methods: NCT05919238 is an ongoing multi-center Phase I light dose-escalation study. Key inclusion criteria are stage III LA-PADC with solid tumor contact > 180° in head/uncinate process of the pancreas for the total encasement length up to 3cm and with target artery internal diameter 5-10 mm. VTP is applied via IA placement of an optical fiber, inside a standard angioplasty balloon, in the target artery adjacent to the tumor. Ten minutes intravenous administration of Padeliporfin at a fixed dose of 4 mg/kg immediately followed by 753nm laser illumination through the inflated balloon, for two 5-minute cycles with 1-minute break. The study is designed to evaluate three light power densities: 200, 400 and 600mW/cm. The primary objectives include determination of Maximum Tolerated light Dose (MTD) and/or recommended phase 2 dose (RP2D) and evaluation of safety. Secondary objectives are to determine rate of surgical downstaging and resectability as well as the pattern of disease progression following VTP treatment, based on pre- and post-VTP contrast computed tomography (CT) scans and tissue specimens, in case surgery is performed. The study comprises two parts: part A with 3+3 light dose escalation schema; part B (expansion cohort) with the RP2D/MTD, derived in Part A. As of 28 October 2025, Cohort 1 of Part A with an LPD of 200mW/cm have been completed without DLTs. Enrolment to cohort 2, with LPD 400mW/cm, began in November 2025. Clinical trial information: NCT05919238 .

IntroductionImmunotherapy is revolutionizing the management of multiple cancer types. However, only a subset of patients responds to immunotherapy. One mechanism of resistance is the absence of immune infiltrates within the tumor. In situ vaccine with local means of tumor destruction that can induce immunogenic cell death have been shown to enhance tumor T cell infiltration and increase efficacy of immune checkpoint blockade.MethodsHere, we compare three different forms of localize tumor destruction therapies: radiation therapy (RT), vascular targeted photodynamic therapy (VTP) and cryoablation (Cryo), which are known to induce immunogenic cell death, with their ability to induce local and systemic immune responses in a mouse 4T1 breast cancer model. The effects of combining RT, VTP, Cryo with anti-PD1 was also assessed.ResultsWe observed that RT, VTP and Cryo significantly delayed tumor growth and extended overall survival. In addition, they also induced regression of non-treated distant tumors in a bilateral model suggesting a systemic immune response. Flow cytometry showed that VTP and Cryo are associated with a reduction in CD11b+ myeloid cells (granulocytes, monocytes, and macrophages) in tumor and periphery. An increase in CD8+ T cell infiltration into tumors was observed only in the RT group. VTP and Cryo were associated with an increase in CD4+ and CD8+ cells in the periphery.ConclusionThese data suggest that cell death induced by VTP and Cryo elicit similar immune responses that differ from local RT.

Background:Bronchoscopic ablation of tumors in the lung periphery may offer unique advantages over traditional surgical resection or radiation. Bronchoscopic vascular targeted photodynamic therapy (VTP) is a second-generation photodynamic therapy that avoids excessive tissue extravasation and is rapidly cleared from the circulation. These advantages avoid prolonged photosensitivity and allow for infusion and illumination within the same procedure. The treatment effect and systemic inflammatory response precipitated by VTP may prove advantageous for anticancer effects, alone or in combination with immune oncology therapies. Research Question:A baseline understanding of this modality's effect on lung parenchyma is needed to provide further guidance toward its potential as a method for bronchoscopic ablation of lung tumors. We report on our initial experimentation with bronchoscopic lung VTP in normal pigs. Study Design and Methods:We performed conventional bronchoscopy for deployment of optical fibers into the peripheral lung. We then infused the photosensitizer WST11 after which we immediately performed illumination of the optical fibers. Results:Our results across 13 pigs with varied survival (between 1 day and 30 days) demonstrate initial feasibility and reasonable safety. Posttreatment radiology and pathology support measurable ablation fields and expected post-VTP changes. Interpretation:Our preclinical evidence provides early rationale for the study of safety and feasibility of bronchoscopic VTP ablation of peripheral lung cancers in humans.

TPS4204 Background: Pancreatic cancer is the third most common cause of cancer death. Surgery offers the best survival rates however only a minority of patients are eligible. Approximately 15-20% of patients are deemed unresectable due to vascular involvement LA. Conversion of unresectable tumors, due to vascular involvement to resectable, is an unmet clinical need. Methods: A novel approach was developed to destroy the tumor encasing the artery combining padeliporfin, a photosensitive drug, locally activated by laser light illumination. The effectiveness of the strategy was confirmed in an orthotopic mouse model. A proof-of-concept study using 12 non-tumor pigs demonstrated an acceptable safety profile. A phase I dose escalation trial (NCT5918783) will be performed to evaluate the safety and maximal tolerated dose (MTD) of laser light dose of padeliporfin VTP. VTP will be delivered through an endovascular fiber integrated in a standard angioplasty balloon. The balloon will be advanced under fluoroscopy to the encased vascular segment of the superior mesenteric artery (SMA) and inflated. Following IV administration of padeliporfin, it will be activated by the laser light. Part A will be a classic 3+3 dose-escalation design to determine the MTD of laser light. The identified MTD will be applied in the Part B for preliminary efficacy evaluation. The primary objectives are to determine safety and MTD and/or recommended phase 2 laser light dose of VTP treatment. Secondary objectives are: rate of surgical conversion; evaluation of the pattern of disease progression (local regional and/or metastatic disease) after VTP based on CT. Standard of care surgery can be performed after 14 days post VTP. Key inclusion criteria: patients with histologically/cytologically confirmed stage III unresectable LA-PDAC in the head/uncinate process of the pancreas, with SMA solid tumor contact ˃180° with measurable disease per RECIST 1.1 and ECOG 0-1. Key exclusion criteria: metastatic disease, other malignancy, photosensitive skin diseases or porphyria, concurrent investigational therapy within past 30 days, medically uncontrolled moderate or severe ascites, previous radiation to pancreas, SMA variants. Recruitment begins in April 2024. Conversion of unresectable locally advanced pancreatic cancer to surgery is a critical unmet need. This phase I trial explores a novel approach to treat the tumor encasement enabling surgery. Clinical trial information: NCT5918783 .

Abstract Pancreatic cancer is a fatal disease: the patient usually has a very poor prognosis and limited treatment options. It is projected to be the second leading cause of cancer-related death by 2030. It is estimated that 80% of patients have metastatic or localized disease with vascular involvement at presentation, not amenable to surgery. Thus, a therapy that will convert unresectable, due to vascular involvement, tumors to resectable is an unmet medical need. We developed a novel treatment relying on endovascular activation of a photosensitizer Padeliporfin, by a vascular-targeted photodynamic therapy (VTP) to clear the artery from the encasing tumor enabling surgery. Padeliporfin is administered intravenously and activated locally by illumination via an optical fiber, deployed within the tumor encased artery by an angioplasty procedure under fluoroscopy. In a proof-of-concept study in normal swine model, treatment induced areas of ablation in normal pancreatic parenchyma while sparing the artery and other major structures in it’s vicinity. Drug and light doses used were proved effective in other solid tumors in preclinical and clinical studies. Safety was evaluated in a controlled study comprised of 12 pigs subjected to Padeliporfin VTP in a superior mesenteric artery (SMA). Two light doses were tested. Control groups received no drug or no illumination and drug. Follow up was 48 hours or seven days post treatment. Clinical observations and blood test results did not reveal any signs of decreased wellness without differences between treated and control groups. Lipase results were unchanged compared to the baseline. Amylase levels were within the normal range in all animals. Histopathology findings 48 hours post VTP in the SMA and surrounding tissues were similar in treated and control animals. Observed changes were manifested as small lesions consistent with angioplasty procedure impact, involving less than 25% of the media circumference. Small foci of coagulative necrosis were observed in the pancreatic parenchyma in the vicinity of SMA. In the seven-day samples, there was media pressure necrosis in occasional sections of the artery in all groups involving less than 25% of the circumference, attributed to the angioplasty procedure. Minimal fibrosis in a few samples, consisted of focal areas of fibroblast proliferation, indicating early regeneration, with no architectural or thickness changes of the arterial wall. The tissues surrounding SMA as well as organs downstream to the treated artery were mostly within normal ranges. Our results demonstrate that endovascular Padeliporfin VTP is feasible and has an acceptable safety profile together with evidence of ability to ablate pancreatic tumors encasing major abdominal arteries. The efficacy is further supported by our studies showing effective tumor ablations in orthotopic mouse models especially in combination with immune modulating therapies. A phase I trial (NCT5918783) aims to evaluate the potential of this approach for converting unresectable pancreatic cancer patients to amenable for surgery. Citation Format: Dina Preise, Yaniv Cohen, Genia Alpert, Zachary Sacks, Tamar Yechezkel, Natalia Kudinova, Eyal Morag, Ehud Willenz, Julia Rothman, Keren Brook, Inna Krasnopolskaya, Lilach Agemy, Sofia Zilber, Hooman Yarmohammadi, David Kelsen, David Perry, Avigdor Scherz. A novel approach to convert non-resectable pancreatic cancer with major artery involvement using endovascular activation of Padeliporfin by vascular-targeted photodynamic therapy [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr LB_C05.

Detecting and mapping metabolism in tissues represents a major step in detecting, characterizing, treating and understanding cancers. Recently introduced deuterium metabolic imaging techniques could offer a noninvasive route for the metabolic imaging of animals and humans, based on using 2 H magnetic resonance spectroscopic imaging (MRSI) to detect the uptake of deuterated glucose and the fate of its metabolic products. In this study, 2 H6,6' -glucose was administered to mice cohorts that had been orthotopically implanted with two different models of pancreatic ductal adenocarcinoma (PDAC), involving PAN-02 and KPC cell lines. As the tumors grew, 2 H6,6' -glucose was administered as bolii into the animals' tail veins, and 2 H MRSI images were recorded at 15.2 T. 2D phase-encoded chemical shift imaging experiments could detect a signal from this deuterated glucose immediately after the bolus injection for both the PDAC models, reaching a maximum in the animals' tumors ~ 20 min following administration, and nearly total decay after ~ 40 min. The main metabolic reporter of the cancers was the 2 H3,3' -lactate signal, which MRSI could detect and localize on the tumors when these were 5 mm or more in diameter. Lactate production time traces varied slightly with the animal and tumor model, but in general lactate peaked at times of 60 min or longer following injection, reaching concentrations that were ~ 10-fold lower than those of the initial glucose injection. This 2 H3,3' -lactate signal was only visible inside the tumors. 2 H-water could also be detected as deuterated glucose's metabolic product, increasing throughout the entire time course of the experiment from its ≈10 mM natural abundance background. This water resonance could be imaged throughout the entire abdomen of the animals, including an enhanced presence in the tumor, but also in other organs like the kidney and bladder. These results suggest that deuterium MRSI may serve as a robust, minimally invasive tool for the monitoring of metabolic activity in pancreatic tumors, capable of undergoing clinical translation and supporting decisions concerning treatment strategies. Comparisons with in vivo metabolic MRI experiments that have been carried out in other animal models are presented and their differences/similarities are discussed.

Background There is a need to improve the treatment of prostate cancer (PCa) and reduce treatment side effects. Vascular-targeted photodynamic therapy (VTP) is a focal therapy for low-risk low-volume localised PCa, which rapidly disrupts targeted tumour vessels. There is interest in expanding the use of VTP to higher-risk disease. Tumour vasculature is characterised by vessel immaturity, increased permeability, aberrant branching and inefficient flow. FRT alters the tumour microenvironment and promotes transient ‘vascular normalisation’. We hypothesised that multimodality therapy combining fractionated radiotherapy (FRT) and VTP could improve PCa tumour control compared against monotherapy with FRT or VTP. Methods We investigated whether sequential delivery of FRT followed by VTP 7 days later improves flank TRAMP-C1 PCa tumour allograft control compared to monotherapy with FRT or VTP. Results FRT induced ‘vascular normalisation’ changes in PCa flank tumour allografts, improving vascular function as demonstrated using dynamic contrast-enhanced magnetic resonance imaging. FRT followed by VTP significantly delayed tumour growth in flank PCa allograft pre-clinical models, compared with monotherapy with FRT or VTP, and improved overall survival. Conclusion Combining FRT and VTP may be a promising multimodal approach in PCa therapy. This provides proof-of-concept for this multimodality treatment to inform early phase clinical trials.

BACKGROUND: Urologic guidelines recommend perioperative instillation of chemotherapy after transurethral resection of bladder tumor (TURBT) to decrease tumor recurrence, yet implementation of this recommendation is partial due to associated morbidity. Hypertonic saline destroys cells by osmotic dehydration and might present a safer alternative. OBJECTIVE: To evaluate the safety of 3% hypertonic saline (Hypersal) intravesical instillation following TURBT in rats and in humans. METHODS: In 8 rats whose bladders were electrically injured, intravesical blue-dyed Hypersal was administered. We measured serum sodium levels before and after instillation and pathologically evaluated their pelvic cavity for signs of inflammation or blue discoloration. Twenty-four patients were recruited to the human trial (NIH-NCT04147182), 15 comprised the interventional and 10 the control group (one patient crossed over). Hypersal was given postoperatively. Serum sodium was measured before, 1 hour and 12–24 hours after instillation. Adverse effects were documented and compared between the groups. RESULTS: In rats, average sodium levels were 140.0 mEq/L and 140.3 mEq/L before and following instillation, respectively. Necropsy revealed no signs of inflammation or blue discoloration. In humans the average plasma sodium levels were 138.6 mEq∖L, 138.8 mEq∖L and 137.7 mEq∖L before, 1 hour and 12–24 hours after instillation, respectively. During the postoperative follow-up there was one case of fever. A month after the surgery, dysuria was reported by 5 patients while urgency and hematuria were reported by one patient each. The most severe adverse events were grade 2 on the Clavien-Dindo scale. Adverse events were similar in the control group. CONCLUSIONS: Hypersal instillation is safe and tolerable immediately after TURBT.

Purpose Deuterium metabolic imaging (DMI) maps the uptake of deuterated precursors and their conversion into lactate and other markers of tumor metabolism. Even after leveraging 2 H’s short T 1 s, DMI’s signal‐to‐noise ratio (SNR) is limited. We hypothesize that a multi‐echo balanced steady‐state free precession (ME‐bSSFP) approach would increase SNR compared to chemical shift imaging (CSI), while achieving spectral isolation of the metabolic precursors and products. Methods Suitably tuned 2 H ME‐bSSFP (five echo times [TEs], ΔTE = 2.2 ms, repetition time [TR]/flip‐angle = 12 ms/60°) was implemented at 15.2T and compared to CSI (TR/flip‐angle = 95 ms/90°) regarding SNR and spectral isolation, in simulations, in deuterated phantoms and for the in vivo diagnosis of a mouse tumor model of pancreatic adenocarcinoma (N = 10). Results Simulations predicted an SNR increase vs. CSI of 3‐5, and that the peaks of 2 H‐water, 2 H 6,6’ ‐glucose, and 2 H 3,3’ ‐lactate can be well isolated by ME‐bSSFP; phantoms confirmed this. In vivo, at equal spatial resolution (1.25 × 1.25 mm 2 ) and scan time (10 min), 2 H 6,6’ ‐glucose’s and 2 H 3,3’ ‐lactate’s SNR were indeed higher for bSSFP than for CSI, three‐fold for glucose (57 ± 30 vs. 19 ± 11, P < .001), doubled for water (13 ± 5 vs. 7 ± 3, P = .005). The time courses and overall localization of all metabolites agreed well, comparing CSI against ME‐bSSFP. However, a clearer localization of glucose in kidneys and bladder, the detection of glucose‐avid rims in certain tumors, and a heterogeneous pattern of intra‐tumor lactate production could only be observed using ME‐bSSFP’s higher resolution. Conclusions ME‐bSSFP provides greater SNR per unit time than CSI, providing for higher spatial resolution mapping of glucose uptake and lactate production in tumors.

This study explored the usefulness of multiple quantitative MRI approaches to detect pancreatic ductal adenocarcinomas in two murine models, PAN‐02 and KPC. Methods assayed included 1 H T 1 and T 2 measurements, quantitative diffusivity mapping, magnetization transfer (MT) 1 H MRI throughout the abdomen and hyperpolarized 13 C spectroscopic imaging. The progress of the disease was followed as a function of its development; studies were also conducted for wildtype control mice and for mice with induced mild acute pancreatitis. Customized methods developed for scanning the motion‐ and artifact‐prone mice abdomens allowed us to obtain quality 1 H images for these targeted regions. Contrasts between tumors and surrounding tissues, however, were significantly different. Anatomical images, T 2 maps and MT did not yield significant contrast unless tumors were large. By contrast, tumors showed statistically lower diffusivities than their surroundings (≈8.3 ± 0.4 x 10 −4 for PAN‐02 and ≈10.2 ± 0.6 x 10 −4 for KPC vs 13 ± 1 x 10 −3 mm 2 s −1 for surroundings), longer T 1 relaxation times (≈1.44 ± 0.05 for PAN‐02 and ≈1.45 ± 0.05 for KPC vs 0.95 ± 0.10 seconds for surroundings) and significantly higher lactate/pyruvate ratios by hyperpolarized 13 C MR (0.53 ± 0.2 for PAN‐02 and 0.78 ± 0.2 for KPC vs 0.11 ± 0.04 for control and 0.31 ± 0.04 for pancreatitis‐bearing mice). Although the latter could also distinguish early‐stage tumors from healthy animal controls, their response was similar to that in our pancreatitis model. Still, this ambiguity could be lifted using the 1 H‐based reporters. If confirmed for other kinds of pancreatic tumors this means that these approaches, combined, can provide a route to an early detection of pancreatic cancer.

Purpose: To evaluate the riboflavin (RF) concentration and distribution in the corneal stroma and the risk for endothelial photodamage during corneal crosslinking (CXL) following 10- and 30-minute impregnation. Methods: De-epithelialized rabbit corneas were subjected to impregnation for 10 and 30 minutes with different RF formulations. Human corneal endothelial cells (HCECs) were subjected to different RF concentrations and ultraviolet A (UVA) dosages. Assays included fluorescence imaging, absorption spectroscopy of corneal buttons and anterior chamber humor, and cell viability staining. Results: After 10 and 30 minutes of impregnation, respectively, anterior chamber fluid showed an RF concentration of (1.6 ± 0.21)•10−4% and (5.4 ± 0.21)•10−4%, and trans-corneal absorption reported an average corneal RF concentration of 0.0266% and 0.0345%. This results in a decrease in endothelial RF concentration from 0.019% to 0.0056%, whereas endothelial UVA irradiance increases by 1.3-fold when changing from 30 to 10 minutes of impregnation. HCEC viability in cultures exposed to UVA illumination and RF concentrations as concluded for the endothelium after 10- and 30-minute impregnation was nonstatistically different at 51.0% ± 3.9 and 41.3 ± 5.0%, respectively. Conclusions: The risk for endothelial damage in CXL by RF/UVA treatment does not increase by shortened impregnation because the 30% increase in light intensity is accompanied by a 3.4-fold decrease of the RF concentration in the posterior stroma. This is substantiated by similar endothelial cell toxicity seen in vitro, which in fact appears to favor 10-minute impregnation. Translational Relevance: This study offers compelling arguments for (safely) shortening RF impregnation duration, reducing patients' burden and costly operation room time.

The development of cancer is tightly related to the successful evasion of neoplastic tissue from immune system surveillance, which represents a key obstacle in tumor therapy. Most conventional therapies (surgery, chemotherapy and radiation) target the tumor cells directly or indirectly, while immunotherapy attempts to enhance host anti-tumor response. In a manner similar to surgery, photodynamic therapy (PDT), also a local tumor therapy, aims at tumor ablation in its initial acute phase. Treatment success is mainly determined by tumor eradication and the absence of local recurrences. However, experience gained over several decades of therapeutic application has repeatedly hinted at long term therapeutic effects of PDT, suggesting activation of the immune system by this treatment modality. Such contribution of the immune system to treatment success was widely confirmed in many laboratories in various preclinical and some clinical studies. In this present short review, we wish to present our modest contribution to this potential therapeutic trend describing the immune response upon application of a novel photosensitizing methodology: vascular targeted photodynamic therapy (VTP) developed in our laboratories. This modality differs from classical PDT in most aspects (sensitizer: Pd-bacteriochlorophyll and consequent spectral wavelength in the near infrared, the generated photochemistry, the treatment target, treatment objective, treatment protocol and more). For example in contrast to the tumor cells that constitute the target of classical PDT, the targets of VTP are the tumor-feeding arteries and draining veins whose almost instant occlusion (minutes) leads to tumor blood stasis and eradication. Some of the mechanistic features of the induced immune response, such as innate and acquired cellular and humoral mediators, induction of new antigens, resulting from oxidative modifications and implications for anti-tumor vaccination in this different treatment environment, are discussed. VTP is about to enter phase III clinical trials for the therapy of prostate cancer and the potential involvement of the immune system may contribute an interesting aspect for the understanding and future development of this treatment modality.

Vascular targeted photodynamic therapy with TOOKAD-from local ablation to systemic cancer treatment Background: Local therapies that allow for safe ablation of primary lesions and trigger anti-tumor immunity with minimal side effects, may be particularly effective in management of early-stage cancer. Vascular-targeted photodynamic therapy (VTP) with TOOKAD®, recently granted EMA approval as a first-line treatment for localized prostate cancer, has been shown by us to also trigger anti-tumor immunity. Our recent preclinical and current clinical studies aim to test the hypothesis that synchronizing TOOKAD®VTP with immune-modulation that attenuates the pro-tumor immunity, will result in systemic micrometastases annihilation and a high cure rate. Methods: 4T1-Luc, adenosquamous JA and Met-Lu cells were orthotopically grafted in the mammary pad, esophagus and prostate of immune-competent mice and rats, respectively. Seven days postgrafting, tumors were treated with TOOKAD®VTP, with or without immune-modulators. Immune profiles were examined by 10-X genomics, FACS analysis and immunohistochemistry. Animal survival and lung and lower abdomen metastases counts were followed up for 3 months. Clinical protocols were composed based on the preclinical data and utilized in the clinical studies that will be described in other lectures of this session. Results: TOOKAD®VTP triggered anti-tumor immunity sufficient to achieve 60-90% cure in various cancer models. However, primary lesion annihilation did not prevent disease progression in the more aggressive cancers such as 4T1-Luc breast cancer. TOOKAD®VTP synchronized with metronomic administration of immune-modulators was associated with a 60-90% disease-free animals and resistance to re-challenge. The rate of success was highly pending on the exact synchronization of the immune modulating agents with the VTP timing. The required modulators match the deciphered immune profiles. This combined immuno-VTP therapy concept has been translated to clinical trials currently ongoing at Memorial Sloan Kettering Cancer Center. Conclusion: Application of TOOKAD®VTP to localized tumors combined with immune modulation appears to provide novel means to treat early disseminated cancers.

Background: Vascular targeted photodynamic therapy (VTP) is based on in-situ photosensitization of a circulating drug leading to intravascular reactive oxygen species (ROS) generation and the subsequent tumors' blood vessel occlusion that lead to the tumor necrosis. We have developed a series of bacteriochlorophyll derivatives, among them WST11 (TOOKAD®-Soluble) a water-soluble agent that has just been granted approval by the European community (EMA) for the treatment of early/intermediate prostate cancer. Application to other cancers, specifically to pancreatic ductal adenocarcinoma (PDAC) is being evaluated and may require adjustments of the treatment conditions. The following work presents the first pre-clinical results using WST11-VTP to treat syngeneic PDAC in mice. Methods: We utilize KPC cells derived from genetically engineered mouse model of spontaneous pancreatic adenocarcinoma to induce orthotopic PDAC tumor in C57B mice. Cells are injected in the mouse pancreas and are treated 7 days post-implantation. WST11 is injected i.v. by constant rate infusion followed by illumination of the exposed tumor at 755nm. Tumor growth is monitored using a Vevo 3100 US imaging apparatus. In parallel experiments, a window exposing the pancreas blood vasculature through a glass coverslip is positioned in a few mice. This allows live monitoring of the new angiogenic blood vessels during treatment using a fluorescent microscope and speckle imaging techniques. Results: WST11-VTP of orthotopic KPC tumors was tested using different drug/light doses. Two doses produced 75-80% tumor necrosis with minimal toxicity, namely 5/7 mg/kg WST11 combined with 100/120mW light. One month post-VTP, the surviving mice were sacrificed histopathological evaluations revealed dramatic tumor shrinkage and necrosis in the treated animals. Moreover, the combination of VTP with Gemcitabine seemed to further improve the treatment success. Conclusions: WST11-VTP showed good safety/efficacy profile while applied to orthotopic KPC tumors in syngeneic mice. The combination with Gemcitabine seem to be beneficial and is being further evaluated. These results might in the future rationalize early clinical trials in PDAC patients. Legal entity responsible for the study: Weizmann Institute of Science Funding: Robert and Yaddle Sklare Professiorail Chair in Biochemistry and the Wade Thompson Family foundation. Disclosure: All authors have declared no conflicts of interest.

Introduction: Vascular targeted photodynamic therapy (VTP) based on local sensitization of circulating WST11, a water-soluble derivative of Pd-bacteriochlorophyll, enables effective focal ablation of solid tumors. Highly toxic oxygen radicals are produced in the vascular lumen upon illumination with near infra-red light (753nm) instigating immediate cascade of events leading to blood clotting and vasoconstriction culminating with complete and irreversible occlusion of tumor feeding arteries and draining veins. Importantly, WST11 clears rapidly from the circulation and does not accumulate in the body, except transient accumulation in the clearance-associated organs such as kidney and liver, providing high level of safety and minimizing the risk of adverse effects. Here we evaluate WST11-VTP safety and efficacy for the treatment of esophageal cancer aiming for development of clinically translatable treatment protocol. Methods: We have developed an orthotopic rat model in which esophageal cancer cells are implanted in the mid esophagus in the submucosa layer using endoscopy guided procedure. Established tumors are illuminated with cylindrical diffuser deployed through a custom built endoscopy guided system immediately after intravenous infusion of WST11. For assessment of treatment safety and tissue recovery normal esophagus was subjected to WST11-VTP with the same treatment set up using both rat and porcine models. Safety and efficacy were evaluated histologically by examining sections of treated tumors and normal esophageal tissues under various treatment conditions and by monitoring animal weight in rats and several blood parameters in pigs. Results: WST11-VTP applied on healthy esophageal tissues produced a necrotic damage confined to the illuminated zone with pronounced inflammatory response while collateral damage to adjacent neighboring tissues was not observed. The impact runs as deep as the muscularis propria without signs of perforation or death as a result of the procedure and full recovery was observed 40 days after WST11-VTP. Moreover, performing WST11-VTP after administration of anti-VEGF antibodies (Avastin™), did not induce any additional morbidity. WST11-VTP of established orthotopic tumors in rat resulted in significant survival advantage compared to animals illuminated without WST11 administration (light control) Conclusion: WST11-VTP was found to be safe when applied to normal rat and porcine esophagus both alone and following Avastin™ administration. Importantly, WST11-VTP effectively eradicated established esophageal tumors in tested set up with clinically relevant drug and light dose suggesting rapid translation to a clinical treatment protocol.

Abstract Vascular-targeted photodynamic therapy with WST11 (VTP) enables safe and efficient non-thermal ablation of solid tumors as demonstrated by recent phase II and III clinical trials with localized prostate cancer. Studies in animal models in our labs revealed that VTP of immunogenic tumors elicits innate/adaptive immune responses and over 80% cures with consequent long-lasting anti-tumor protection. Here we show that local VTP combined with immune modulation in rodents, bearing weakly immunogenic prostate and triple negative breast tumors, results in eradication of remote metastases and animal cure. Methodology: 4T1-luc cells were subcutaneously grafted at the hind leg of Balb/C mice. Colony forming assay confirmed tumor cell spreading to the lungs already by day 7 post grafting when local VTP was delivered to the primary tumor. The study comprised: (i) animals treated by VTP alone or (ii) following 50mg/kg cyclophosphamide (CTX) on day 4 post grafting, or (iii) VTP combined with anti-CTLA4 antibodies administered on days 1, 4, 7 and 10 post VTP according to standard protocol. Appropriate control groups using immunomodulatory agents alone or untreated tumors were utilized. Cure was defined as absence of detectable primary or metastatic tumor by necropsy at 90 days. Mat-Lu-luc prostate cancer cells were grafted orthotopically in Copenhagen rats. Surgical removal of tumor bearing prostate and follow up of disease progression demonstrated that on day 10 post grafting, the day of VTP, metastatic spread has already been initiated in 57% of animals, eventually developing abdominal and visceral metastases. Treatment groups comprised (i) animals treated by VTP with or (ii) without CTX pre-treatment followed by prostate removal three days after VTP or (iii) surgery only. Results: Treatment of primary 4T1-luc tumors with VTP resulted in a complete primary tumor ablation in 50% of treated animals. Less then 10% of animals treated with VTP alone were cured with the rest developing lung metastases, while combination with CTX resulted in 30% cures. CTX induced reduction of total cell counts in tumor draining lymph nodes (LN) and spleens on VTP day followed by cell expansion over the following four days. Significant CTX-mediated reduction of Foxp3+ cells accompanied by increase in CD8+ cells during this period could be responsible for observed anti-metastatic effect of the combined treatment. Moreover, no significant change in total CD4+ cells observed at the same time suggests expansion of T helper cell subsets with concomitant suppression of regulatory population. Anti-CTLA-4 treatment, although significantly improved primary response rates after sub-optimal VTP (56% vs 14% in combined group vs VTP), did not prevent metastases suggesting additional escape mechanisms. VTP of orthotopic prostate tumors followed by whole gland removal resulted in 45% metastatic rate vs 57% in group treated by surgery alone on the same day. Pre-treatment with 50mg/kg CTX three days prior to VTP reduced metastatic rate to 7%. These findings suggest VTP-induced immune response can be augmented by prior immune modulation. Conclusions: Our results demonstrate that immunomodulation combined with local VTP enables systemic anti-tumor effects with impact on the development of early metastatic disease in the setting of poorly immunogenic tumors. The choice of different immune modulatory agents and timing of treatment appears to play a critical role in the treatment outcome. Further studies are in progress to evaluate combination of WST11-VTP with more than one immunomodulating agent to further characterize localized and systemic response and augment treatment success. These studies serve as pre-clinical support for clinical trials, exploiting the immunogenic effects of VTP for tumor ablation, being developed in collaboration with Memorial Sloan Kettering Cancer Center. Note:This abstract was not presented at the conference. Citation Format: Dina Preise, Natasha Kudinova, Uri Lindner, Keren Sasson, Ronny Uzana, Jonathan Coleman, Yoram Salomon, Avigdor Scherz. Immunomodulated VTP enables cure of metastatic prostate and breast cancers in animal models. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr B012.

You have accessJournal of UrologyProstate Cancer: Basic Research & Pathophysiology I1 Apr 2016MP62-07 NEOADJUVANT IMMUNOMODULATION COMBINED WITH VASCULAR TARGETED THERAPY PREVENTS METASTASES AND IMPROVES SURVIVAL IN RATS WITH LOCALLY ADVANCED PROSTATE CANCER. Uri Lindner, Dina Preise, Natasha Kudinova, Arkady Agarounov, Yoram Salomon, Jonathan A. Coleman, Dan Leibovici, and Avigdor Scherz Uri LindnerUri Lindner More articles by this author , Dina PreiseDina Preise More articles by this author , Natasha KudinovaNatasha Kudinova More articles by this author , Arkady AgarounovArkady Agarounov More articles by this author , Yoram SalomonYoram Salomon More articles by this author , Jonathan A. ColemanJonathan A. Coleman More articles by this author , Dan LeiboviciDan Leibovici More articles by this author , and Avigdor ScherzAvigdor Scherz More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.02.915AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Vascular targeted photodynamic (VTP) therapy using WST11 has been clinically investigated as a focal therapy for localized Prostate Cancer (PCa). Preclinical studies showed that WST11-VTP creates a strong antitumor immune reaction by exposing tumor antigens and danger associated molecular patterns, hastening immune cells to the ablated area and more. We set out to evaluate if treatment with cyclophosphamide (CTX) as an immune modulator prior to VTP might reduce/prevent metastatic disease in an orthotopic animal model of locally advanced aggressive PCa. METHODS Stage 1: luciferin transfected PCa androgen insensitive cells with propensity to metastasize (Mat- Lu) were grafted into immunocompetent Copenhagen rats. Cells were implanted orthotopically and 8-13 days later the prostate was removed. Animals were continuously monitored for the development of metastasis. Stage 2: PCa was implanted orthotopically, 7 days after implantation the rats were randomly treated by CTX or saline followed by WST11-VTP three days after CTX. On day 13 post implantation the prostate gland was surgically removed. Whole body metastastatic growth was monitored clinically and by bioluminescence. Animals not exhibiting metastatic disease were sacrificed after 60 days and subjected to a histological evaluation. RESULTS In stage 1, metastases were observed in 18 and 46% of the animals that underwent surgical removal of the prostate at day 8 (N=11) and 10 (N=13) post PCa implantation respectively. Prostate removal was not technically feasible at day 13 due to locally advanced disease and animals did not survive the procedure, hence, day 10 was selected for the first invasive intervention. In stage 2, 15 male rats underwent immunomodulation with CTX followed by VTP and prostate removal, 12 rats had VTP and prostate removal without immunomodulation. One animal (7%) in the immunomodulation group developed metastatic disease whereas in the control group six animals (50%) developed metastatic disease (p=0.02). All animals not exhibiting metastases survived until end of study. CONCLUSIONS Immunomodulation with CTX synchronized with WST11-VTP prior to prostatic surgical removal at the early dissemination stage, reduced/prevented the development of metastatic disease in the PCa rat model. Surgery alone or VTP combined with surgery resulted in a 46%, 50% metastatic rate. Our data suggest that WST11-VTP initiates an immune response that upon augmentation by pre-treatment with CTX, results in the significant reduction of metastases and a high cure rate. This finding warrants further evaluation in clinical settings. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e814 Advertisement Copyright & Permissions© 2016MetricsAuthor Information Uri Lindner More articles by this author Dina Preise More articles by this author Natasha Kudinova More articles by this author Arkady Agarounov More articles by this author Yoram Salomon More articles by this author Jonathan A. Coleman More articles by this author Dan Leibovici More articles by this author Avigdor Scherz More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...