Search

Gene-mediated cytotoxic immunotherapy (GMCI) is an immuno-oncology approach involving local delivery of a replication-deficient adenovirus expressing herpes simplex thymidine kinase (AdV-tk) followed by anti-herpetic prodrug activation that promotes immunogenic tumor cell death, antigen-presenting cell activation, and T cell stimulation. This phase I dose-escalation pilot trial assessed bronchoscopic delivery of AdV-tk in patients with suspected lung cancer who were candidates for surgery. A single intra-tumoral AdV-tk injection in three dose cohorts (maximum 1012 viral particles) was performed during diagnostic staging, followed by a 14-day course of the prodrug valacyclovir, and subsequent surgery 1 week later. Twelve patients participated after appropriate informed consent. Vector-related adverse events were minimal. Immune biomarkers were evaluated in tumor and blood before and after GMCI. Significantly increased infiltration of CD8+ T cells was found in resected tumors. Expression of activation, inhibitory, and proliferation markers, such as human leukocyte antigen (HLA)-DR, CD38, Ki67, PD-1, CD39, and CTLA-4, were significantly increased in both the tumor and peripheral CD8+ T cells. Thus, intratumoral AdV-tk injection into non-small-cell lung cancer (NSCLC) proved safe and feasible, and it effectively induced CD8+ T cell activation. These data provide a foundation for additional clinical trials of GMCI for lung cancer patients with potential benefit if combined with other immune therapies., Graphical Abstract, Predina and colleagues describe a phase I dose-escalation trial using bronchoscopic delivery of a replication-deficient adenovirus expressing herpes simplex thymidine kinase (AdV-tk) in lung cancer patients who underwent surgery. AdV-tk injection proved safe, feasible, and effectively induced CD8+ T cell activation in blood and in resected tumor tissues.

BackgroundIntratumoral viral oncolytic immunotherapy is a promising new approach for the treatment of a variety of solid cancers. CAN-2409 is a replication-deficient adenovirus that delivers herpes simplex virus thymidine kinase to cancer cells, resulting in local conversion of ganciclovir or valacyclovir into a toxic metabolite. This leads to highly immunogenic cell death, followed by a local immune response against a variety of cancer neoantigens and, next, a systemic immune response against the injected tumor and uninjected distant metastases. CAN-2409 treatment has shown promising results in clinical studies in glioblastoma (GBM). Patients with GBM are usually given the corticosteroid dexamethasone to manage edema. Previous work has suggested that concurrent dexamethasone therapy may have a negative effect in patients treated with immune checkpoint inhibitors in patients with GBM. However, the effects of dexamethasone on the efficacy of CAN-2409 treatment have not been explored.MethodsIn vitro experiments included cell viability and neurosphere T-cell killing assays. Effects of dexamethasone on CAN-2409 in vivo were examined using a syngeneic murine GBM model; survival was assessed according to Kaplan-Meier; analyses of tumor-infiltrating lymphocytes were performed with mass cytometry (CyTOF - cytometry by time-of-flight). Data were analyzed using a general linear model, with one-way analysis of variance followed by Dunnett’s multiple comparison test, Kruskal-Wallis test, Dunn’s multiple comparison test or statistical significance analysis of microarrays.ResultsIn a mouse model of GBM, we found that high doses of dexamethasone combined with CAN-2409 led to significantly reduced median survival (29.0 days) compared with CAN-2409 treatment alone (39.5 days). CyTOF analyses of tumor-infiltrating immune cells demonstrated potent immune stimulation induced by CAN-2409 treatment. These effects were diminished when high-dose dexamethasone was used. Functional immune cell characterization suggested increased immune cell exhaustion and tumor promoting profiles after dexamethasone treatment.ConclusionOur data suggest that concurrent high-dose dexamethasone treatment may impair the efficacy of oncolytic viral immunotherapy of GBM, supporting the notion that dexamethasone use should be balanced between symptom control and impact on the therapeutic outcome.

BACKGROUND CAN-3110 (rQNestin34.5v2) is an HSV-1 oncolytic viral immunotherapy with one copy of the inflammatory ICP34.5 gene under transcriptional control of the Nestin glioma-specific promoter. We completed a phase 1 sequential dose-escalation trial of CAN-3110 in recurrent high-grade glioma (rHGG). METHODS CAN-3110 was injected intratumorally starting at 1x106 plaque forming units (pfu) and dose- escalated by half log up to 1x1010 pfu in biopsy confirmed rHGG. An expansion cohort of 12 patients was then accrued at 1x109 pfus. Blood and post-injection rHGG were collected. RESULTS 41 rHGG patients were treated (42 separate interventions): median age 56 years (range 27-74); 21 females, 20 males; median baseline KPS 90 (range 70-100). CAN-3110 administration was well-tolerated with no dose limiting toxicities. Median overall survival (mOS) was 11.9 months. Histologic and molecular analyses showed significantly increased T cell infiltration in post treatment samples with elevated T cell and/or B cell receptor (TCR/BCR) transcripts which correlated with patient survival (HR 0.26 for patients with elevated TCR/BCR rearrangements as compared to patients with low). Volumetric analyses of MRI suggest a trend between reduction in the relative change in tumor growth, TCR/BCRs enrichment and survival in CAN-3110 treated patients. CLINICAL IMPLICATIONS Administration of CAN-3110 into rHGG was well tolerated. OS of CAN-3110 treated subjects compare favorably to historical controls. The association of increased TCR/BCR transcripts with survival suggests that CAN-3110 induces T cell responses against rHGG, supporting further clinical development of CAN-3110 viral immunotherapy.

Background Gene-mediated cytotoxic immunotherapy (GMCI) is a tumor-specific immune stimulatory strategy implemented through local delivery of aglatimagene besadenovec (AdV-tk) followed by anti-herpetic prodrug. GMCI induces T-cell dependent tumor immunity and synergizes with radiotherapy. Clinical trials in adult malignant gliomas demonstrated safety and potential efficacy. This is the first trial of GMCI in pediatric brain tumors. Methods This phase I dose escalation study was conducted to evaluate GMCI in patients 3 years of age or older with malignant glioma or recurrent ependymoma. AdV-tk at doses of 1 × 1011 and 3 × 1011 vector particles (vp) was injected into the tumor bed at the time of surgery followed by 14 days of valacyclovir. Radiation started within 8 days of surgery, and if indicated, chemotherapy began after completion of valacyclovir. Results Eight patients (6 glioblastoma, 1 anaplastic astrocytoma, 1 recurrent ependymoma) were enrolled and completed therapy: 3 on dose level 1 and 5 on dose level 2. Median age was 12.5 years (range 7-17) and Lansky/Karnofsky performance scores were 60-100. Five patients had multifocal/extensive tumors that could not be resected completely and 3 had gross total resection. There were no dose-limiting toxicities. The most common possibly GMCI-related adverse events included Common Terminology Criteria for Adverse Events grade 1-2 fever, fatigue, and nausea/vomiting. Three patients, in dose level 2, lived more than 24 months, with 2 alive without progression 37.3 and 47.7 months after AdV-tk injection. Conclusions GMCI can be safely combined with radiation therapy with or without temozolomide in pediatric patients with brain tumors and the present results strongly support further investigation. Clinical trial registry ClinicalTrials.gov NCT00634231.

9037 Background: Immune checkpoint inhibitors (ICI) are standard of care for advanced NSCLC. Even among patients with initial response, a majority ultimately progress, and rational combination approaches are needed to improve outcomes. CAN-2409 is a replication-deficient adenoviral gene construct that delivers the thymidine kinase gene, resulting in local conversion of a prodrug (valacyclovir) into a toxic metabolite. This leads to tumor cell lysis and immunization against the injected tumor and uninjected metastases. We have previously shown that monotherapy intra-tumoral (IT) delivery of CAN-2409 followed by oral valacyclovir in NSCLC patients is safe and results in CD8+ T cell infiltration in the injected tumor and activation of this cell population in tissue and peripheral blood. Methods: This open-label Ph2 experimental medicine clinical trial evaluates safety and clinical activity of IT CAN-2409 combined with ICI (± chemo) for stage III/IV NSCLC. Three cohorts are defined based on response to ICI at enrollment: stable disease (SD; Cohort 1; C1), progressive disease (PD) after ≥18 weeks (w) of ICI (Cohort 2; C2), or ICI refractory disease (RD; Cohort 3; C3). Two doses of CAN-2409 (5x1011 vp) are given 5-7w apart via bronchoscopic or percutaneous injection into a lung tumor, disease-positive lymph node or peripheral metastasis, followed by valacyclovir. Patients are assessed for safety, immunologic biomarkers (analysis in progress), and clinical response. Results: As of data cutoff (10Jan22), 28 patients received ≥1 dose of CAN-2409 (safety population). Median age was 70 years; 86% stage IV; 32% squamous; 11% PD-L1 >50%; 82% receiving pembrolizumab and 18% nivolumab. Study treatment and procedures were generally well tolerated. The most common TRAEs were Gr1/2, with fatigue, fever, and chills in 18-39% of patients; 1 patient had Gr3 fever. Twenty-two patients are alive and 6 patients died due to disease. Of the 14 RECIST evaluable patients who received 2 doses of CAN-2409, clinical response was seen in 4 patients (Table 1). Two PRs are ongoing (6w, 24w) and reduction in tumor size was observed in non-injected lesions. In C2, 6 of 7 patients achieving SD are ongoing with median duration of 13w (range 10-40w). Conclusions: The addition of CAN-2409 for patients with advanced NSCLC and inadequate response to front-line ICI (± chemo) appears to be well tolerated. Preliminary clinical data suggest that CAN-2409 induced a clinical response in 4/14 evaluable patients and produced disease stabilization in most patients entering the trial with PD, with evidence of abscopal effect in a subset of patients. Clinical trial information: NCT04495153. [Table: see text]

Background Gene-mediated cytotoxic immunotherapy (GMCI) is a local tumor immunotherapy that uses aglatimagene besadenovec (a non-replicating serotype 5 adenovirus, expressing HSV1 thymidine kinase) with the prodrug ganciclovir to induce DNA double strand breaks (DSB), leading to immunogenic tumor cell death and intratumoral immune cell invasion. Here we investigate potential repressors and enhancers of GMCI’s effectiveness. GMCI is currently in clinical trials in combination with immune checkpoint blockade in glioblastoma. Thus we set out to identify potential areas to improve this approach for future application. Dexamethasone is used in symptomatic treatment of glioma patients, although it is known to cause immune suppression. However, the influence of dexamethasone on the efficacy of GMCI has not been explored. In contrast, DNA damage response inhibitors like the ATR inhibitor (ATRi) AZD6738 might not only amend the cytotoxic but also the immunogenic profile of GMCI, rendering it an attractive combination partner. Methods We investigated the effects of ATR-inhibition and dexamethasone on GMCI in vitro using cytotoxicity, flow cytometry and T-cell-killing assays in glioblastoma cell lines. The impact of dexamethasone and ATRi in vivo was assessed in an orthotopic syngeneic murine glioblastoma model. Tumor immune infiltrates were analyzed with flow cytometry. Results Cytotoxicity assays showed that dexamethasone has a slight impact on GMCI in vitro. In T-cell-functional assays, we observed a significantly impaired tumor cell killing. Immune cell response assays revealed a reduced immune cell proliferation after co-culture with supernatant from dexamethasone or combination treated glioblastoma cells. In vivo, while treatment with GMCI alone resulted in longer median symptom-free survival (39.5d) versus no treatment (23d), the combination of GMCI and dexamethasone resulted in the significant reduction of this effect (29d vs 39.5d ; p = 0.0184). The combination of ATRi with GMCI proved to be synergistic in cytotoxicity assays. Flow cytometry revealed a significant increase in DSB-associated H2AX foci as well as an improved immune profile by downregulation of GMCI-induced PD-L1 expression. In vivo, the combination with ATRi led to an increase in long-term surviving animals (66.7%) compared to GMCI (50%) and proved to be highly significant compared to the untreated control (p=0.0022). Conclusions Our data suggest that dexamethasone may decrease the efficacy of immunotherapy for glioma through impaired T cell function: this emphasizes the need in identifying alternatives to dexamethasone to prevent attenuated responses in immunotherapies. The combination of GMCI with ATRi however points to additional therapeutic benefit through enhanced cytotoxic efficacy, improved immunogenicity in vitro and increased long-term survival in vivo, making it a promising future approach for the treatment of glioblastoma. Acknowledgements This was supported by NCI P01CA069246 (Chiocca)

BACKGROUND CAN-2409 is a replication-deficient adenovirus that delivers HSV thymidine kinase to cancer cells, resulting in local conversion of orally administered valacyclovir into a toxic metabolite. Previously, a phase 1b/2 clinical trial of CAN-2409 combined with standard-of-care (SOC) demonstrated safety and improved survival in HGG patients. Addition of CAN-2409 to nivolumab has the potential to activate locally recruited lymphocytes and teach them to recognize tumor neoantigens, changing the ‘cold’ immunosuppressive tumor microenvironment, and synergizing with the activity mediated by immune checkpoint inhibitors. This notion is supported by preclinical experiments showing that the combination of CAN-2409 with anti-PD1 therapy was more effective than either treatment alone. METHODS This ongoing phase 1 clinical trial evaluates safety and initial efficacy of CAN-2409 combined with nivolumab and SOC in newly diagnosed HGG. CAN-2409 is injected during neurosurgery into the tumor bed, followed by 14-days of valacyclovir. Radiation starts within 8 (+/-4) days of surgery. Temozolomide is administered to MGMT-methylation positive patients only. Nivolumab is given every 2 weeks, up to 52-weeks. Deep immune profiling studies are ongoing and initial results will be available shortly. RESULTS From February 2019 to March 2021, 41 patients were enrolled and 35 were evaluable for safety from the combination of CAN-2409, nivolumab and SOC: 24 male and 11 female; 34 glioblastoma, 1 diffuse astrocytoma; 33 IDH-wildtype, 2 IDH-mutant; 15 MGMT-methylated, 20 unmethylated. Median age was 62-years (range 28-79), median KPS 90 (range 80-100). With 13 months median follow-up, no unexpected serious adverse events were observed, and 23 patients are still alive. The most frequent possibly related adverse events (>10%) were nausea, fatigue, fever, headache, and increased ALT. CONCLUSIONS The combination of CAN-2409 + nivolumab + SOC was well tolerated. Clinical follow-up and extensive biomarker analyses will provide a better understanding of the therapeutic potential of this approach.

BackgroundRecurrent high-grade glioma (HGG) represents a significant clinical unmet need with expected survival between 6 to 9 months. Oncolytic viruses are a new therapeutic approach for solid tumors that deploy oncolytic activity combined with local and systemic immune activation. CAN-3110 (rQNestin34.5v2) is an oncolytic herpes simplex virus (HSV), modified to encode the HSV1 ICP34.5 protein under control of the nestin promoter. Selective expression of nestin in brain tumors confers tumor-restricted replication of CAN-3110. We conducted an open-label dose-escalation phase 1 clinical trial in patients with recurrent HGG to evaluate safety, tolerability, and immunological changes after CAN-3110 treatment.MethodsThirty patients with biopsy-confirmed recurrent HGG were enrolled from September 2017 to February 2020. CAN-3110 was injected intratumorally starting at 1x106 plaque forming units (pfu) and dose-escalated by half log to 1x1010 pfu. Patients also received standard of care. Peripheral blood mononuclear cells (PBMCs), plasma and tumor samples were collected for analysis at different time-points post treatment. We evaluated HSV antigen expression in tumor tissue. RNA sequencing and T cell receptor (TCR) rearrangement analysis was performed in matched tissue and PBMCs. Cytokine profiling was completed in 29 patients at baseline, day 2, and day 28 post treatment.ResultsEighteen patients were recruited at their first recurrence and 12 at the second recurrence. Three patients presented with multifocal disease. Tumor volume ranged from 357.4 to and 54,036.1mm3 (median 7,733.9mm3, SDV 15,610.2). CAN-3110 was well-tolerated with no dose-limiting toxicity. Median overall survival was 11.7 months. We demonstrated persistence of HSV antigen and CD8+ T cell infiltrates at the site of injected tumor. Preliminary analysis revealed expansion of shared TCR clonotypes and upregulation of pro-inflammatory genes in post-treatment tumors and peripheral blood samples. Longitudinal modeling of cytokine profiling demonstrated increased levels of IL-6, VEGF alpha, CCL2 and IL1-RA and a decrease in GCP-2 levels at day 2 post-treatment (p ConclusionsIntratumoral administration of CAN-3110 appears well-tolerated in recurrent HGG. Histologic, molecular, and cytokine analyses demonstrate persistence of viral antigen as well as local and systemic immune activation after treatment.Ethics ApprovalThe study was approved by the Office for Human Research Studies at Dana-Farber Cancer Institute, Protocol Number 16–557.

The immune system interacts closely with tumors during the disease development and progression to metastasis. The complex communication between the immune system and the tumor cells can prevent or promote tumor growth. New therapeutic approaches harnessing protective immunological mechanisms have recently shown very promising results. This is performed by blocking inhibitory signals or by activating immunological effector cells directly. Immune checkpoint blockade with monoclonal antibodies directed against the inhibitory immune receptors CTLA-4 and PD-1 has emerged as a successful treatment approach for patients with advanced melanoma. Ipilimumab is an anti-CTLA-4 antibody which demonstrated good results when administered to patients with melanoma. Gene therapy has also shown promising results in clinical trials. Particularly, Herpes simplex virus (HSV)-mediated delivery of the HSV thymidine kinase (TK) gene to tumor cells in combination with ganciclovir (GCV) may provide an effective suicide gene therapy for destruction of glioblastomas, prostate tumors and other neoplasias by recruiting tumor-infiltrating lymphocytes into the tumor. The development of new treatment strategies or combination of available innovative therapies to improve cell cytotoxic T lymphocytes trafficking into the tumor mass and the production of inhibitory molecules blocking tumor tissue immune-tolerance are crucial to improve the efficacy of cancer therapy.

2009 Background: Recurrent glioma patients have few therapeutic options and an expected survival of only 7 to 10 months. New treatments to improve the prognosis of this patient population are a dire medical need. Oncolytic viruses (OVs) are emerging as important new agents for cancer treatment. The first FDA approved OV was talimogene laherparepvec (Imlygic, T-Vec) for treatment of melanoma. T-Vec, as most other clinical HSV-1 based OVs, is deleted in the ICP34.5 gene, which is responsible for HSV-1 neurovirulence. However, deletion of ICP34.5 also impedes efficient viral replication. CAN-3110 (rQNestin34.5v2) maintains a copy of the HSV1 ICP34.5 gene under transcriptional control of the tumor-specific promoter for nestin to drive robust tumor-selective replication. CAN-3110 replicates in malignant glioma cells far above levels seen with ICP34.5 deleted viruses. This potency also created the hypothetical risk for increased neurovirulence, thus the regulatory advice to conduct a cautious nine-dose-level Phase-1 dose escalation study in patients with recurrent high-grade glioma (HGG). Methods: From September 2017 to February 2020, thirty patients with biopsy-confirmed recurrent high-grade glioma were treated in an open label clinical trial. Patients with multifocal, multicentric, tumors larger than 5 cm, and tumors that had recurred multiple times were eligible. All patients received best standard of care treatments as indicated by their physician. CAN-3110 was injected intratumorally starting at 1x106 plaque forming units (pfu) and dose-escalating (3+3 design) by half log increments up to 1x1010 pfu. Tissue (when possible) and blood samples were obtained before and during treatment for experimental medicine analyses. Results: CAN-3110 was well tolerated with no dose limiting toxicity observed. The initial tissue diagnosis of the recurrent tumor for the 30 subjects was 26 glioblastoma, 3 anaplastic oligodendroglioma, and 1 anaplastic astrocytoma. The median overall survival (mOS) of the entire study group is 13.25 months. Post-treatment tissue is available for 18/30 subjects and revealed persistence of HSV antigen and CD8+ T cell infiltrates. Additional response, immunologic (including T cell receptor repertoire), transcriptomic and single cell RNA sequencing analyses are ongoing. Conclusions: Administration of CAN-3110 into recurrent glioma was well tolerated without evidence of ICP34.5-induced encephalitis/meningitis. Histological and molecular analyses showed evidence of biological activity and that CAN-3110 injection was associated with immune activation and viral antigen persistence. Although definitive clinical efficacy cannot be determined in this small phase 1 study, OS of CAN-3110 treated subjects compares favorably to historical reports and warrants further clinical studies. Clinical trial information: NCT03152318.

BACKGROUND: Gene Mediated Cytotoxic Immunotherapy (GMCI) generates a polyvalent anti-tumor immune response through local delivery of aglatimagene besadenovec (AdV-tk) which synergizes with standard of care (SOC). METHODS: A Phase II trial was designed to evaluate overall survival (OS) after GMCI + SOC compared to a concurrent matched control group meeting protocol criteria and SOC at an institution not active in the treatment trial. Primary efficacy analysis was planned on the null hypothesis of no improvement in the 2-yr survival over the SOC group with planned subset analysis of significant disease prognostic factors. RESULTS: From 2006 to 2010, 48 patients completed SOC + GMCI and 134 SOC in the matched cohort. There were no dose-limiting toxicities. Fever, fatigue and headache were the most common GMCI-related symptoms. Median OS was 17.1 and 13.5 months for GMCI + SOC and SOC, respectively (hazard ratio [HR] 0.72, 95% confidence interval [CI] 0.52-0.99, p = 0.0417). Median PFS was 8.1 and 6.5 months for GMCI + SOC and SOC, respectively (HR 0.66, 95% CI 0.48-0.91, p = 0.0100). OS at 1- 2- and 3-years increased from 57%, 22% and 8% to 67%, 35% and 19%, respectively. The improvement was mostly in patients that underwent gross total resection: median OS increased from 16.9 to 25 months (p = 0.0492); 1- 2- and 3-year survival rates from 64%, 28% and 6% to 90%, 53% and 32%. CONCLUSIONS: GMCI can be safely combined with SOC in newly diagnosed malignant gliomas. Survival rates compared favorably to historical reports and a matched control group. Survival outcomes were significantly improved in patients with minimal residual disease after total resection. The 2-yr survival rate met the planned statistical threshold for significance. This is the first study to demonstrate a correlation between maximum debulking and a survival advantage using immunotherapy. These data strongly support further evaluation of GMCI for malignant gliomas.

9050 Background: GMCI is a tumor-specific immuno-oncology approach implemented through local delivery of aglatimagene besadenovec(AdV-tk) followed by anti-herpetic prodrug. This leads to immunogenic tumor cell death, antigen presenting cell activation, and T cell stimulation resulting in CD8+ T cell dependent protection, as demonstrated in preclinical models and clinical trials in other tumor types. This is the first study to assess endobronchial delivery of AdV-tk for NSCLC. Methods: This Phase I dose escalation trial enrolled patients with suspected NSCLC who were candidates for surgery. A single AdV-tk injection was performed by endobronchial ultrasound (n = 11) or mediastinoscopy (n = 1) during the diagnostic staging procedure 3 weeks prior to surgery. Three dose levels were evaluated: 2.5x 1011, 5x1011, and 1x1012 vector particles (vp) in a 3+3 design. Valacyclovir was administered for 14 days, starting the day after AdV-tk injection. To assess the local and systemic effects of GMCI, immune biomarkers were evaluated in blood and tumor samples before and after GMCI. Results: From 2017-2019, 12 patients (9 men, 3 women, median age 65 [range 55-80]) received GMCI followed by surgery. Average tumor size was 5.1 cm (largest diameter) and final pathologic stage was I (n = 4), II (n = 3), and III (n = 5). Treatment-related adverse events were CTC grade 1 fever (n = 1), flu-like symptoms (n = 1) and nausea/vomiting/diarrhea (n = 1). The only > grade 2 lab abnormality was transient grade 3 lymphopenia (n = 2). A measurable reduction in tumor size was observed in one patient. The average amount of tumor necrosis was 29.4%. Significant infiltration of CD8+T cells (5.2-fold compared to baseline, p = 0.001) was found in tumor 19-22 days after AdV-tk injection. Within the CD8+tumor infiltrating lymphocytes, there was increased expression of CD38 (2.5-fold, p = 0.002), Ki67 (4.8-fold, p = 0.02), PD1 (1.9-fold, p = 0.002), CD39 (2.9-fold, p = 0.04) and CTLA-4 (4.8-fold, p < 0.001), without significant detected differences in Tim3 or TIGIT. Simultaneously, peripheral blood CD8+ cells displayed significant increases in CD38 (3.4-fold, p = 0.006), HLA-DR (4.2-fold, p = 0.002), and Ki67 (5.8-fold, p = 0.017). Conclusions: Intratumoral injection of AdV-tk into lung tumors was safe and feasible. Further, AdV-tk effectively induced peripheral blood and intra-tumoral CD8 T cell activation. Consequent upregulation of inhibitory receptors suggests a potential benefit for combination therapies. Clinical trial information: NCT03131037.

While surgical resection of pancreatic adenocarcinoma provides the only chance of cure, long-term survival remains poor. Immunotherapy may improve outcomes, especially as adjuvant to local therapies. Gene-mediated cytotoxic immunotherapy (GMCI) generates a systemic anti-tumor response through local delivery of an adenoviral vector expressing the HSV-tk gene (aglatimagene besadenovec, AdV-tk) followed by anti-herpetic prodrug. GMCI has demonstrated synergy with standard of care (SOC) in other tumor types. This is the first application in pancreatic cancer.Four dose levels (3 × 10(10) to 1 × 10(12) vector particles) were evaluated as adjuvant to surgery for resectable disease (Arm A) or to 5-FU chemoradiation for locally advanced disease (Arm B). Each patient received two cycles of AdV-tk + prodrug.Twenty-four patients completed therapy, 12 per arm, with no dose-limiting toxicities. All Arm A patients were explored, eight were resected, one was locally advanced and three had distant metastases. CD8(+) T cell infiltration increased an average of 22-fold (range sixfold to 75-fold) compared with baseline (p = 0.0021). PD-L1 expression increased in 5/7 samples analyzed. One node-positive resected patient is alive66 months without recurrence. Arm B RECIST response rate was 25 % with a median OS of 12 months and 1-year survival of 50 %. Patient-reported quality of life showed no evidence of deterioration.AdV-tk can be safely combined with pancreatic cancer SOC without added toxicity. Response and survival compare favorably to expected outcomes and immune activity increased. These results support further evaluation of GMCI with more modern chemoradiation and surgery as well as PD-1/PD-L1 inhibitors in pancreatic cancer.

Gene-mediated cytotoxic immunotherapy (GMCI) is an immune strategy implemented through local delivery of an adenovirus-based vector expressing the thymidine kinase gene (aglatimagene besadenovec, AdV-tk) followed by anti-herpetic prodrug valacyclovir. A phase I dose escalation trial of GMCI followed by chemotherapy was conducted in patients with malignant pleural effusion (MPE). AdV-tk was administered intrapleurally (IP) in three cohorts at a dose of 1 × 10(12) to 10(13) vector particles. Primary endpoint was safety; secondary endpoints included response rate, progression-free survival, and overall survival. Nineteen patients were enrolled: median age 67 years; 14 with malignant mesothelioma, 4 non-small-cell lung cancer (NSCLC), and 1 breast cancer. There were no dose limiting toxicities. All 3 patients in cohort 2 experienced transient cytokine release syndrome (CRS). Addition of celecoxib in cohort 3 reduced the incidence and severity of CRS (none > grade 2). Three patients are alive (23–33 months after GMCI), and 3 of 4 NSCLC patients had prolonged disease stabilization; one is alive 29 months after GMCI, 3.6 years after initial diagnosis. GMCI was safe and well tolerated in combination with chemotherapy in patients with MPE and showed encouraging response. Further studies are warranted to determine efficacy.

Background Combined immunotherapy approaches are promising cancer treatments. We evaluated anti-programmed cell death protein 1 (PD-1) treatment combined with gene-mediated cytotoxic immunotherapy (GMCI) performed by intratumoral injection of a prodrug metabolizing nonreplicating adenovirus (AdV-tk), providing in situ chemotherapy and immune stimulation. Methods The effects of GMCI on PD ligand 1 (PD-L1) expression in glioblastoma were investigated in vitro and in vivo. The efficacy of the combination was investigated in 2 syngeneic mouse glioblastoma models (GL261 and CT-2A). Immune infiltrates were analyzed by flow cytometry. Results GMCI upregulated PD-L1 expression in vitro and in vivo. Both GMCI and anti-PD-1 increased intratumoral T-cell infiltration. A higher percentage of long-term survivors was observed in mice treated with combined GMCI/anti-PD-1 relative to single treatments. Long-term survivors were protected from tumor rechallenge, demonstrating durable memory antitumor immunity. GMCI led to elevated interferon gamma positive T cells and a lower proportion of exhausted double positive PD1+TIM+CD8+ T cells. GMCI also increased PD-L1 levels on tumor cells and infiltrating macrophages/microglia. Our data suggest that anti-PD-1 treatment improves the effectiveness of GMCI by overcoming interferon-induced PD-L1-mediated inhibitory signals, and GMCI improves anti-PD-1 efficacy by increasing tumor-infiltrating T-cell activation. Conclusions Our data show that the GMCI/anti-PD-1 combination is well tolerated and effective in glioblastoma mouse models. These results support evaluation of this combination in glioblastoma patients.

Glioblastoma multiforme (GBM) is the most common primary malignant tumor of the central nervous system (CNS) and one of the most lethal cancers in adults and children. Despite aggressive treatment with surgery, radiation, and chemotherapy, median survival is less than 15 months and overall survival is less than 10 % at 5 years. Development of therapeutics for malignant gliomas has been hampered by their natural complexity as well as protective mechanisms unique to the CNS. Better understanding of the pathogenesis of GBM is opening the path to novel, specific-targeted therapies. Recently, multiple immunotherapy approaches have been acquiring substantial indication of therapeutic efficacy with a very safe profile. Examples of the leading clinical approaches for GBM will be discussed in detail in this review.

Purpose Despite aggressive therapies, median survival for malignant gliomas is less than 15 months. Patients with unmethylated O6-methylguanine–DNA methyltransferase (MGMT) fare worse, presumably because of temozolomide resistance. AdV-tk, an adenoviral vector containing the herpes simplex virus thymidine kinase gene, plus prodrug synergizes with surgery and chemoradiotherapy, kills tumor cells, has not shown MGMT dependency, and elicits an antitumor vaccine effect. Patients and Methods Patients with newly diagnosed malignant glioma received AdV-tk at 3 × 1010, 1 × 1011, or 3 × 1011 vector particles (vp) via tumor bed injection at time of surgery followed by 14 days of valacyclovir. Radiation was initiated within 9 days after AdV-tk injection to overlap with AdV-tk activity. Temozolomide was administered after completing valacyclovir treatment. Results Accrual began December 2005 and was completed in 13 months. Thirteen patients were enrolled and 12 completed therapy, three at dose levels 1 and 2 and six at dose level 3. There were no dose-limiting or significant added toxicities. One patient withdrew before completing prodrug because of an unrelated surgical complication. Survival at 2 years was 33% and at 3 years was 25%. Patient-reported quality of life assessed with the Functional Assessment of Cancer Therapy-Brain (FACT-Br) was stable or improved after treatment. A significant CD3+ T-cell infiltrate was found in four of four tumors analyzed after treatment. Three patients with MGMT unmethylated glioblastoma multiforme survived 6.5, 8.7, and 46.4 months. Conclusion AdV-tk plus valacyclovir can be safely delivered with surgery and accelerated radiation in newly diagnosed malignant gliomas. Temozolomide did not prevent immune responses. Although not powered for efficacy, the survival and MGMT independence trends are encouraging. A phase II trial is ongoing.

Esophageal carcinoma is the most rapidly increasing tumor in the United States and has a dismal 15% 5-year survival. Immunotherapy has been proposed to improve patient outcomes; however, no immunocompetent esophageal carcinoma model exists to date to test this approach. We developed two mouse models of esophageal cancer by inoculating immunocompetent mice with syngeneic esophageal cell lines transformed by cyclin-D1 or mutant HRAS(G12V) and loss of p53. Similar to humans, surgery and adjuvant chemotherapy (cisplatin and 5-fluorouracil) demonstrated limited efficacy. Gene-mediated cyototoxic immunotherapy (adenoviral vector carrying the herpes simplex virus thymidine kinase gene in combination with the prodrug ganciclovir; AdV-tk/GCV) demonstrated high levels of in vitro transduction and efficacy. Using in vivo syngeneic esophageal carcinoma models, combining surgery, chemotherapy and AdV-tk/GCV improved survival (P=0.007) and decreased disease recurrence (P0.001). Mechanistic studies suggested that AdV-tk/GCV mediated a direct cytotoxic effect and an increased intra-tumoral trafficking of CD8 T cells (8.15% vs 14.89%, P=0.02). These data provide the first preclinical evidence that augmenting standard of care with immunotherapy may improve outcomes in the management of esophageal carcinoma.

The limitations of current forms of prostate cancer therapy have driven researchers to search for new alternatives. Previously we showed cytopathic effect related to HSV-tk in prostate cancer. In this study we present initial results of a neoadjuvant HSV-tk gene therapy trial and address some of the potential mechanistic aspects of its effect in human tissues. We enrolled 23 men with clinically localized prostate cancer but high risk for recurrence in this Phase I-II trial. Intraprostatic viral injections (one to four) were followed by 2 weeks of ganciclovir and prostatectomy 2-4 weeks later. Toxicity was modest. Surgical specimens were embedded fully and whole-mount slides were imaged and analyzed for areas of cytopathic effect. The larger the tumor the greater the cytopathic effect. The effect also seems to be related to areas of high CAR expression. However, the number of injection sites did not influence effect. Local (CD8+ cells and macrophages) and systemic immune response (CD8+ and activated CD8+, IL-12) was increased in patients treated with HSV-tk. Increased apoptosis and decreased microvessel density were also noted in these patients. The results suggest a tumor-specific effect mediated by systemic and local immune response, antiangiogenic effect, and modulation of apoptosis.

Background & Aims: An extrahepatic human neutrophil collagenase complementary DNA (matrix metalloprotease-8) cloned in an adenovirus vector was used as a therapeutic agent in cirrhosis. Methods: A high titer of clinical-grade AdMMP8 was obtained. Results: HeLa cells transduced with AdMMP8 expressed recombinant matrix metalloprotease-8 messenger RNA and matrix metalloprotease-8 protein. Matrix metalloprotease-8 in culture sups showed enzymatic activity against native collagen type I, which was inhibited by ethylenediaminetetraacetic acid, 1,10-phenanthroline, and tissue inhibitor of metalloprotease-1. In vivo transduction showed matrix metalloprotease-8 activity, and studies to establish the efficacy of this characterized vector were performed in CCl 4 and bile duct-ligated cirrhotic rats. Transduction with 3 × 10 11 viral particles per kilogram resulted in hepatic detection of both messenger RNA and protein matrix metalloprotease-8. A consistent response in fibrosis reversal was observed in CCl 4 rats. Liver fibrosis in bile duct-ligated cirrhotic animals was decreased in 45%, along with diminished hydroxyproline content, after AdMMP8 treatment. The expression of matrix metalloprotease-2 and matrix metalloprotease-3 was up-regulated in AdMMP8 rats. Free tissue inhibitor of metalloprotease-1, as an indirect measurement of active uncomplexed matrix metalloproteases, was also increased in the AdMMP8 groups. Transforming growth factor-β messenger RNA was diminished, and matrix metalloprotease-9 and hepatocyte growth factor increased. Treatment in both models correlated with improvements in ascites, functional hepatic tests, and gastric varices, indicating diminished intrahepatic blood pressure in animals injected with AdMMP8. Conclusions: Therefore, therapy with the matrix metalloprotease-8 gene is promising for use in a clinical setting.

There is an evolving role for combining radiotherapy (RT) with gene therapy in the management of prostate cancer. However, the clinical results of this combined approach are much needed. The preliminary results addressing the safety of this Phase I-II study combining RT and gene therapy (adenovirus/herpes simplex virus-thymidine kinase gene/valacyclovir with or without hormonal therapy) in the treatment of prostate cancer have been previously reported. We now report the prostate-specific antigen (PSA) response and biopsy data.This trial was composed of three separate arms. Arm A consisted of low-risk patients (Stage T1-T2a, Gleason score7, pretreatment PSA10 ng/mL) treated with combined RT-gene therapy. A mean dose of 76 Gy was delivered to the prostate with intensity-modulated RT. They also received adenovirus/herpes simplex virus-thymidine kinase/valacyclovir gene therapy. Arm B consisted of high-risk patients (Stage T2b-T3, Gleason score6, pretreatment PSA level10 ng/mL) treated with combined RT-gene therapy and hormonal therapy (luteinizing hormone-releasing hormone agonist [30-mg Lupron, 4-month depot] and an antiandrogen [flutamide, 250 mg t.i.d. for 14 days]). Arm C consisted of patients with Stage D1 (positive pelvic lymph nodes) who received the same regimen as Arm B with the addition of 45 Gy to the pelvic lymphatics. PSA determination and biopsy were performed before, during, and after treatment. The American Society for Therapeutic Radiology and Oncology consensus definition (three consecutive rises in PSA level) was used to denote PSA failure.Fifty-nine patients (29 in Arm A, 26 in Arm B, and 4 in Arm C) completed the trial. The median age was 68 years (range, 39-85 years). The median follow-up for the entire group was 13.5 months (range, 1.4-27.8 months). Only Arm A patients were observed to have an increase in PSA on Day 14. The PSA then declined appropriately. All patients in Arm A (median follow-up, 13.4 months) and Arm B (median follow-up, 13.9 months) had biochemical control at last follow-up. Three patients in Arm C (with pretreatment PSA of 335, 19.6, and 2.5 ng/mL and a combined Gleason score of 8, 9, and 9 involving all biopsy cores) had biochemical failure at 3, 3, and 7.7 months. Two patients had distant failure in bone and 1 patient in the para-aortic lymph nodes outside the RT portal. Six to twelve prostate biopsies performed in these 3 patients revealed no evidence of residual carcinoma. In Arm A, biopsy showed no evidence of carcinoma in 66.7% (18 of 27), 92.3% (24 of 26), 91.7% (11 of 12), 100% (8 of 8), and 100% (6 of 6) at 6 weeks, 4 months, 12 months, 18 months, and 24 months after treatment, respectively. In Arm B, no evidence of carcinoma on biopsy was noted in 96% (24 of 25), 90.5% (19 of 21), 100% (14 of 14), 100% (7 of 7), and 100% (2 of 2), respectively, in the same interval after treatment.This is the first reported trial of its kind in the field of prostate cancer that aims to expand the therapeutic index of RT by combining it with in situ gene therapy. The initial transient PSA rise in the Arm A patients may have been a result of local immunologic response or inflammation elicited by in situ gene therapy. Additional investigation to elucidate the mechanisms is needed. Hormonal therapy may have obliterated this rise in Arm B and C patients. The biopsy data were encouraging and appeared to show no evidence of malignancy earlier than historical data. Combined RT, short-course hormonal therapy, and in situ therapy appeared to provide good locoregional control but inadequate systemic control in patients with positive pelvic lymph nodes. Longer term use of hormonal therapy in addition to gene therapy and RT has been adopted for this group of patients to maximize both locoregional and systemic control.

Gene therapy may represent a new avenue for the development of multimodal treatment for diverse forms of cirrhosis. This study explores the potential benefits of combining adenovirus-mediated human urokinase-plasminogen activator (AdHuPA) gene delivery and biliodigestive anastomosis to enhance the therapeutic efficacy of each treatment alone for cholestatic disorders resulting in secondary biliary cirrhosis. In an experimental model of secondary biliary cirrhosis, application of 6 x 10(11) vp/kg AdHuPA adenovirus vector resulted in 25.8% liver fibrosis reduction and some improvement in liver histology. The relief of bile cholestasis by a surgical procedure (biliodigestive anastomosis) combined with AdHuPA hepatic gene delivery rendered a synergistic effect, with a substantial 56.9 to 42.9% fibrosis decrease. AdHuPA transduction resulted in clear-cut expression of human uPA protein detected by immunohistochemistry and induction of up-regulation in the expression of metalloproteinases MMP-3, MMP-9, and MMP-2. Importantly, functional hepatic tests, specifically direct bilirubin, were improved. Also, hepatic cell regeneration, rearrangement of hepatic architecture, ascites, and gastric varices improved in cirrhotic rats treated with AdHuPA but not in counterpart AdGFP cirrhotic animals. We believe this might represent a novel therapeutic strategy for human cholestatic diseases.

Developing and conducting gene therapy clinical trials poses unique challenges which must be addressed to satisfy regulatory requirements and, most importantly, to protect human subjects. Experimental products used for gene transfer studies, such as viral vectors, are often complex and cannot be sterilized or completely characterized to the extent of a typical pharmaceutical. Thus, quality and characterization must be built into the production process. Extensive preclinical studies must be performed to determine the feasibility of the approach, the safety of the product, and the appropriate dose range to evaluate in humans. Once a clinical trial is initiated, subjects must be followed carefully for short- and long-term toxicity especially since preclinical studies may not adequately predict the toxicity profile of these novel, complicated products. Results of early phase studies in gene therapy have often sent the investigators back to the laboratory to improve the delivery vector or identify a more potent or less toxic gene. This circular developmental process is expected for the early stages of a new technology such as gene therapy. Although these hurdles appear extensive, they can be overcome, as evidenced by the initiation of more than 500 clinical gene therapy trials in the United States to date, and are imperative for the maintenance of high-quality studies and public trust. This article describes the step-by-step process for developing a gene therapy trial incorporating specific examples relevant to neuro-oncology.

Hasenburg A, Fischer DC, Tong X-W, Rojas-Martinez A, Nyberg-Hoffman C, Orlowska-Volk M, Kohlberger P, Kaufman RH, Ramzy I, Aguilar-Cordova E, Kieback DG. Histologic and immunohistochemical analysis of tissue response to adenovirus-mediated herpes simplex thymidine kinase gene therapy of ovarian cancer.Herpes simplex virus (HSV) thymidine kinase (tk) gene incorporated into adenovirus was delivered intraperitoneally (ip) followed by an antiherpetic prodrug and topotecan in patients with recurrent epithelial ovarian cancer. Tissue response was evaluated. Ten patients underwent secondary debulking with subsequent delivery of ADV-HSV-tk therapy. Two patients each were treated at dose level 1 (2 × 1010 vector particles = VP), 2 (2 × 1011 VP), and 3 (2 × 1012 VP); four patients were treated at dose level 4 (2 × 1013 VP). Five patients underwent second-look surgery about one month after gene therapy (GT). Treatment response, presence of vector DNA, protein expression of steroid hormone receptors, p53, c-erbB2 and Ki67 protein were analyzed. At second-look, two out of five patients were tumor-free and none of their peritoneal biopsies showed vector DNA. After GT, the vital tumor mass was smaller, desmoplastic reaction had increased, and tumors were less differentiated with an increase of Ki67 expression. There was no change in expression of hormone receptors, p53, or c-erbB2. ADV-HSV-tk GT appears to eliminate cells with higher differentiation first and might induce fibrosis. Dedifferentiation might render residual cells more sensitive to chemotherapy secondary to their subsequent higher mitotic activity.

The effects of intravenous administration of a first-generation adenoviral vector expressing beta-galactosidase were compared in two baboons receiving a high dose or lower dose of vector, 1.2 x 10(13) or 1.2 x 10(12) particles/kg, respectively. The high-dose baboon developed acute symptoms, decreased platelet counts, and increased liver enzymes, and became moribund at 48 hr after injection, while the lower-dose baboon developed no symptoms. Expression of the beta-galactosidase transgene was prominent in liver, spleen, and endothelium of the arterial vasculature in the high-dose baboon, but was much more limited and spared the endothelium in the lower-dose baboon. Injury to the vascular endothelium was the most prominent abnormality in the high-dose baboon. Extensive histological studies provide a detailed picture of the pathology associated with a lethal dose of first-generation adenoviral vector in a primate.

Adenoviral vectors efficiently target normal liver cells; however, a clear-cut description of the safety boundaries for using adenovectors in hepatic cirrhosis has not been settled. With this in mind, we used a first-generation, replication-deficient adenoviral vector carrying the E. coli lacZ gene (Ad5betaGal) to monitor therapeutic range, biodistribution, toxicity and transduction efficiency in Wistar rats made cirrhotic by two different experimental approaches resembling alcoholic cirrhosis and biliary cirrhosis in humans. Further, we show proof of concept on fibrosis reversion by a 'therapeutic' Ad-vector (AdMMP8) carrying a gene coding for a collagen-degrading enzyme. Dose-response experiments with Ad5betaGal ranging from 1 x 10(8)-3 x 10(12) viral particles (vp) per rat (250 g), demonstrated that adenovirus-mediated gene transfer via iliac vein at 3 x 10(11 )vp/rat, resulted in an approximately 40% transduction in livers of rats made cirrhotic by chronic intoxication with carbon tetrachloride, compared with approximately 80% in control non-cirrhotic livers. In rats made cirrhotic by bile-duct obstruction only, 10% efficiency of transduction was observed. Biodistribution analyses showed that vector expression was detected primarily in liver and at a low level in spleen and kidney. Although there was an important increase in liver enzymes between the first 48 h after adenovirus injection in cirrhotic animals compared to non-transduced cirrhotic rats, this hepatic damage was resolved after 72-96 h. Then, the cDNA for neutrophil collagenase, also known as Matrix Metalloproteinase 8 (MMP8), was cloned in an Ad-vector and delivered to cirrhotic rat livers being able to reverse fibrosis in 44%. This study demonstrates the potential use of adenoviral vectors in safe transient gene therapy strategies for human liver cirrhosis.

Early clinical trial data show that blockade of PD-1 signaling leads to significant anticancer responses in a subset of patients in certain cancer types. While the brain has traditionally been considered to be an immune-privileged site, evidence supporting the use of immunotherapeutics in brain tumors has been rapidly accumulating. Given that virus-based cancer therapies can be immunostimulatory and immune checkpoint inhibitors block the body's natural checkpoint response, the combination of these two approaches offers a potentially advantageous interaction. One of the molecular underpinnings of T-cell exhaustion is the expression of Programmed Death-1 (PD-1) on T-cells that recognizes its ligand PD-L1. AdV-TK is an immunostimulatory virus-based approach, known as Gene-Mediated Cytotoxic Immunotherapy (GMCI), that involves the intra-tumoral delivery of a non-replicating adenoviral vector carrying the Herpes virus thymidine kinase gene (TK) followed by administration of an anti-herpetic prodrug (ganciclovir GCV) and recently showed encouraging results in a Phase II trial in glioblastoma (Wheeler et al., 2016). The immunological component results from the delivery vehicle being a virus, the mode of cell death, through both necrosis and apoptosis, and the pro-immunogenic properties of the TK protein. We confirm that this approach induces glioblastoma cell death and a consistent anti-tumor immune stimulation. Not surprisingly, however, this immune stimulation also leads to increase in cell surface of immune checkpoint inhibitory ligands on tumor cells, including PD-L1, detected by flow cytometry and immunohistochemistry. We show that GMCI induces a type-I interferon response, and using IFN decoy we demonstrated that the release of IFNβ in vitro is at least partially responsible for autocrine/paracrine PD-L1 up-regulation both in human and mouse glioblastoma cell lines. In vivo studies using an intracranial GL261 model showed high numbers of long term survivors in the GMCI/PD-1 combination (11/14), compared with GMCI (6/16), anti-PD-1 (5/12) and untreated (0/11). In addition, long term survival mice were no longer able to form tumors after rechallenge indicating the establishment of anti-tumor immunity. Finally, tumor infiltrating lymphocytes after GMCI showed an increase in CD8+, CD8+/GranzymeB+, and IFNγ+ cells suggestive of cytotoxic T-cell activation. However, there was also a significant increase in CD4+, CD4+/FoxP3+, and IL-10 indicating a significant infiltration by Tregs, releasing immunosuppressive cytokines. Additionally, there was a significant increase in PD-1+ /TIM3+ T-cells, indicative of an immunosuppressive microenvironment. Overall, our data show that GMCI/anti-PD-1 combinatorial therapy is effective in a syngeneic tumor model, and strongly support clinical trials of GMCI/checkpoint inhibitor combinations in glioblastoma patients. Citation Format: Maria Carmela Speranza, Franz Ricklefs, Carmela Passaro, Sarah R. Klein, Kazue Kasai, Johanna Kaufmann, Hiroshi Nakashima, Bronisz Agnieszka, Estuardo Aguilar-Cordova, Brian W. Guzik, Gordon J. Freeman, David A. Reardon, Patrick Wen, E. Antonio Chiocca, Sean E. Lawler. Preclinical analysis of combinatorial glioblastoma therapy with the prodrug-mediated gene therapy vector AdV-TK and immune checkpoint inhibition. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr B84.

92 Background: Since the U.S. Preventive Task Force recommended against PSA screening in 2012, the polemic between the benefit of early detection and the risk of early overtreatment, has been heightened. Furthermore, in countries where diagnosis is delayed even in symptomatic men and resources are limited for treating advanced disease, the impact of limiting PSA screening may be greater resulting in a shorter incidence/mortality ratio. In Mexico PSA screening is not widely used and many men are never diagnosed with PCa. Thus, the true incidence of PCa is unknown and yet it is the number one cause of cancer morbidity and mortality in men. The current study was designed to evaluate the incidence of PCa in a random population of men from Mexico City using PSA screening. Methods: Prospective enrollment of 3,837 men > 50 years old without previous history of PCa underwent PSA testing. Men with a PSA > 4ng/ml were selected for a second analysis and for completion of a questionnaire on prostate health history. Men with confirmed elevated PSA are being invited to further evaluation and possible biopsy by a urologist. Results: Median age was 59 years (interquartile range 56 to 63 years). In this cohort, 412 (10.8%) men had a total PSA > 4ng/ml (5% of those < 55 years vs. 26% of those > 70 years). From these men, 284 had a repeat PSA approximately 3 months after the first evaluation (median 98 days). A total of 229 men had a 2nd PSA above 4mg/ml, 25 had PSA > 20ng/ml. During evaluations, 309 men completed the questionnaire showing that 29% had previous PSA testing, 11% had a previous DRE, 4% had history of a previous biopsy and 2% identified having a family history of PCa. Conclusions: Greater than 10% (n = 412/3837) of men from a random screen in Mexico City were found to have elevated PSA ( > 4ng/ml). Of these, 12% (n = 48) and 6% (n = 25) had levels consistent with intermediate- and high-risk disease, respectively. Most of these ”high-PSA” patients did not have a previous PSA evaluation despite symptoms, representing a considerable number of patients in whom screening could be life-saving intervention. A low awareness of family history of PCa could be representative of both the lack of diagnosis of PCa and general ignorance regarding this disease. We continue evaluating and doing biopsies to patients with indication.

In an extended phase I/II study we evaluated 36 prostate cancer patients with local recurrence after radiotherapy who received single or repeated cycles of replication-deficient adenoviral vector (ADV)-mediated herpes simplex virus-thymidine kinase (HSV-tk) plus ganciclovir (GCV) in situ gene therapy with respect to serum PSA levels, alterations in immune cells, and numbers of apoptotic cells in needle biopsies. An initial cycle of HSV-tk plus GCV gene therapy caused a significant prolongation of the mean serum PSA-doubling time (PSADT) from 15.9 to 42.5 months (p = 0.0271) and in 28 of the injected patients (77.8%) there was a mean PSA reduction (PSAR) of 28%. It took a mean of 8.5 months for the PSA to return to the initial PSA (TR-PSA) value. A repeated cycle of gene therapy failed to significantly extend PSADT but did result in significant increases in PSAR (29.4%) and TR-PSA (10.5 months). Moderately increased serum adenovirus antibody titers were generally observed 2 weeks after initial vector injection. Also at this time there was a statistically significant increase in the mean percent of CD8(+) T cells positive for the HLA-DR marker of activation in peripheral blood (p = 0.0088). Studies using prostate biopsies obtained at the same time point demonstrated that vector DNA was detectable by PCR in most samples yet all patients remained positive for prostate cancer in at least one biopsy core. Further analysis demonstrated a correlation between the level of CD8(+) cells and the number of apoptotic cells in biopsies containing cancer cells (p = 0.042). We conclude that repeated cycles of in situ HSV-tk plus GCV gene therapy can be administered to prostate cancer patients who failed radiotherapy and have a localized recurrence. Biological responses to this experimental therapy including increases in PSADT, PSAR, and TR-PSA, and activated CD8(+) T cells present in the peripheral blood, were demonstrated. Interestingly, the density of CD8(+) cells in posttreatment biopsies correlated with the number of apoptotic cells.

Purpose: Standard therapies for breast cancer lack tumor specificity and have significant risk for recurrence and toxicities. Herpes simplex virus-thymidine kinase (HSV-tk) gene therapy combined with radiation therapy (XRT) may be effective because of complementary mechanisms and distinct toxicity profiles. HSV-tk gene therapy followed by systemic administration of ganciclovir (GCV) enhances radiation-induced DNA damage by generating high local concentrations of phosphorylated nucleotide analogs that increase radiation-induced DNA breaks and interfere with DNA repair mechanisms. In addition, radiation-induced membrane damage enhances the “bystander effect” by facilitating transfer of nucleotide analogs to neighboring nontransduced cells and by promoting local and systemic immune responses. This study assesses the effect of single and multiple courses of HSV-tk gene therapy in combination with ionizing radiation in a mouse mammary cancer model. Methods and Materials: Mouse mammary TM40D tumors transplanted s.c. in syngeneic immunocompetent BALB-c mice were treated with either adenoviral-mediated HSV-tk gene therapy or local radiation or the combination of gene and radiation therapy. A vector consisting of a replication-deficient (E1-deleted) adenovirus type 5 was injected intratumorally to administer the HSV-tk gene, and GCV was initiated 24 h later for a total of 6 days. Radiation was given as a single dose of 5 Gy 48 h after the HSV-tk injection. A metastatic model was developed by tail vein injection of TM40D cells on the same day that the s.c. tumors were established. Systemic antitumor effect was evaluated by counting the number of lung nodules after treating only the primary tumors with gene therapy, radiation, or the combination of gene and radiation therapy. To assess the therapeutic efficacy of multiple courses of this combinatorial approach, one, two, and three courses of HSV-tk + GCV gene therapy, in combination with radiation, were compared to HSV-tk or XRT alone and to sham-treated animals. (Treatments were repeated at 7-day intervals from the HSV-tk injection.) Results: Both single-therapy modalities reduced tumor growth by 11% compared to controls, while the combined therapy resulted in a decrease of 29%. Median survival was 36 days in the combined therapy group, compared to 33 days in the monotherapy groups and 26 days in the control group. In the metastatic model, the number of lung nodules was reduced by 59.5% after HSV-tk gene therapy, whereas radiotherapy had no effect on metastatic growth. Combined therapy led to an additional 66.7% reduction in lung colonization. Compared to controls, local tumor growth was maximally suppressed by three courses of combined therapy (51.5%), followed by two courses of combined therapy (37.2%), and three sessions of XRT alone (35.6%). Median survival was also significantly prolonged to 58 days with the three courses of combined therapy, followed by two courses, to 45 days. All other treatment groups demonstrated median survival times between 26 and 35 days, while controls had a median survival of 24 days. Conclusions: These results indicate that multiple courses of HSV-tk therapy in combination with radiation improve the therapeutic efficacy of this approach and may provide therapeutic implications for the treatment of human breast cancer and other solid tumors.

To report the preliminary results of a Phase I/II study combining radiotherapy and in situ gene therapy (adenovirus/herpes simplex virus thymidine kinase gene/valacyclovir) with or without hormonal therapy in the treatment of prostate cancer.Arm A: low-risk patients (T1-T2a, Gleason score7, pretreatment PSA10) were treated with combined radio-gene therapy. A mean dose of 76 Gy was delivered to the prostate with intensity-modulated radiotherapy. Arm B: high-risk patients (T2b-T3, Gleason scoreor=7, pretreatment PSAor=10) were treated with combined radio-gene therapy and hormonal therapy. Hormonal therapy was comprised of a 4-month leuprolide injection and 2-week use of flutamide. Arm C: Stage D1 (positive pelvic lymph node) patients received the same regimen as Arm B, with the additional 45 Gy to the pelvic lymphatics. Treatment-related toxicity was assessed using Cancer Therapy Evaluation Program common toxicity score and Radiation Therapy Oncology Group (RTOG) toxicity score.Thirty patients (13 in Arm A, 14 in Arm B, and 3 in Arm C) completed the trial. Median follow-up was 5.5 months. Eleven patients (37%) developed flu-like symptoms (Cancer Therapy Evaluation Program Grade 1) of fatigue and chills/rigors after gene therapy injection but recovered within 24 h. Four patients (13%) and 2 patients (7%) developed Grade 1 and 2 fever, respectively. There was no patient with weight loss. One patient in Arm B developed Grade 3 elevation in liver enzyme, whereas 11 and 2 patients developed Grade 1 and 2 abnormal liver function tests. There was no Grade 2 or above hematologic toxicity. Three patients had transient rise in creatinine. There was no RTOG Grade 3 or above lower gastrointestinal toxicity. Toxicity levels were as follows: 4 patients (13%), Grade 2; 6 patients (20%), Grade 1; and 20 patients (67%), no toxicity. There was 1 patient with RTOG Grade 3 genitourinary toxicity, 12 patients (40%) with Grade 2, 8 patients (27%) with Grade 1, and 9 patients (30%) with no toxicity. No patient dropped out from the trial or had to withhold treatment because of severe toxicity.This is the first trial of its kind in the field of prostate cancer that aims to expand the therapeutic index of radiotherapy by combining in situ gene therapy. Initial experience has demonstrated the safety of this approach. There is no added toxicity to each therapy used alone. Long-term follow-up and larger cohort studies are warranted to evaluate long-term toxicity and efficacy.

Liver cirrhosis represents a worldwide health problem and is a major cause of mortality. Cirrhosis is the result of extensive hepatocyte death and fibrosis induced by chronic alcohol abuse and hepatitis B and C viruses. Successful gene therapy approaches to this disease may require both reversal of fibrosis and stimulation of hepatocyte growth. Urokinase-type plasminogen activator (uPA) may serve this function, as it is an initiator of the matrix proteolysis cascade and induces hepatocyte growth factor expression. In a rat cirrhosis model, a single iv administration of a replication-deficient adenoviral vector encoding a nonsecreted form of human uPA resulted in high production of functional uPA protein in the liver. This led to induction of collagenase expression and reversal of fibrosis with concomitant hepatocyte and improved liver function. Thus, uPA gene therapy may be an effective strategy for treating cirrhosis in humans.

The reporting of adverse events occurring in gene therapy studies is currently under discussion. There are many agencies involved in the reporting of adverse events, often with reporting guidelines that are unique to each organisation. Guidelines differ according to the type of event (adverse event, adverse drug reaction, unexpected adverse drug reaction, serious adverse event and serious adverse drug reaction). While there is a move toward making guidelines more stringent in the US, there is concern that this will increase the number of reports of unrelated events, create confusion from a global perspective, and increase public concern needlessly.

Introduction: Patients with recurrent ovarian cancer were treated with a replication-deficient recombinant adenovirus containing the herpes simplex virus thymidine kinase gene administered intraperitoneally (i.p.) followed by administration of an anti-herpetic prodrug and topotecan. Materials and Methods: A total of 10 patients with stage IIIc epithelial ovarian cancer underwent secondary debulking to ≤0.5 cm residual tumor. Patients with normal i.p. flow received i.p. delivery of adenovirus. Two patients each were treated on dose level 1 (2 × 1010 vector particles (VP)), dose level 2 (2 × 1011 VP), and dose level 3 (2 × 1012 VP); four patients were treated on dose level 4 (2 × 1013 VP). Acyclovir and topotecan were started 24 hours after vector delivery. Results: No patient treated at any dose level incurred unanticipated toxic effects, and all side effects resolved. The most common adverse event was myelosuppression: grade 3 or 4 thrombocytopenia with grade 2–4 anemia in three patients and grade 3 or 4 neutropenia in eight patients. Three patients developed thrombocytosis and three patients had a mild elevation of serum glutamic pyruvic transaminase/alanine aminotransferase. Temperature elevations that were not associated with detectable infection occurred in two patients. Discussion: I.p. delivery of adenoviral vector with concomitant topotecan chemotherapy was well tolerated without significant lasting toxicities. Side effects were independent of the dose of adenoviral vector.

Purpose: We assess risks, toxicity and side effects of multiple and repeat in situ suicide gene therapy in patients with localized prostate cancer.Materials and Methods: The study population comprised patients with localized prostate cancer receiving multiple and/or repeat intraprostatic injections of a replication deficient adenovirus containing the herpes simplex virus thymidine kinase (HSV-tk) gene. Intravenous ganciclovir or oral valaciclovir was given for 14 days after injection. Patients were recruited from 4 different clinical protocols in studies of toxicity and efficacy of suicide gene therapy, and closely monitored for toxicity and side effects during and after treatment. Toxicity was graded according to the Cancer Therapy Evaluation Program common toxicity criteria published by the National Cancer Institute.Results: A total of 52 patients were treated under these clinical protocols with a total of 76 gene therapy cycles. Toxic events were recorded in 16 of 29 patients (55.2%) who were given mul...

Between December 1996 and September 1998, 13 patients with advanced recurrent malignant brain tumors (9 with glioblastoma multiforme, 1 with gliosarcoma, and 3 with anaplastic astrocytoma) were treated with a single intratumoral injection of 2 x 10(9), 2 x 10(10), 2 x 10(11), or 2 x 10(12) vector particles (VP) of a replication-defective adenoviral vector bearing the herpes simplex virus thymidine kinase gene driven by the Rous sarcoma virus promoter (Adv.RSVtk), followed by ganciclovir (GCV) treatment. The VP to infectious unit ratio was 20:1. Our primary objective was to determine the safety of this treatment. Injection of Adv.RSVtk in doses==2 x 10(11) VP, followed by GCV, was safely tolerated. Patients treated with the highest dose, 2 x 10(12) VP, exhibited central nervous system toxicity with confusion, hyponatremia, and seizures. One patient is living and stable 29.2 months after treatment. Two patients survived25 months before succumbing to tumor progression. Ten patients died within 10 months of treatment, 9 from tumor progression and 1 with sepsis and endocarditis. Neuropathologic examination of postmortem tissue demonstrated cavitation at the injection site, intratumoral foci of coagulative necrosis, and variable infiltration of the residual tumor with macrophages and lymphocytes.

For patients with local recurrence of prostate cancer after definitive irradiation therapy there is no treatment widely considered safe and effective. After extensive preclinical testing of prodrug gene therapy in vitro and in vivo, we conducted a phase I dose escalation clinical trial of intraprostatic injection of a replication-deficient adenovirus (ADV) containing the herpes simplex virus thymidine kinase gene (HSV-tk) injected directly into the prostate, followed by intravenous administration of the prodrug ganciclovir (GCV). Our goal was to determine safe dose levels of the vector for future trials of efficacy. Patients with a rising serum prostate-specific antigen (PSA) level and biopsy confirmation of local recurrence of prostate cancer without evidence of metastases one or more years after definitive irradiation therapy were eligible for the trial. After giving informed consent, patients received injections of increasing concentrations of ADV/HSA-tk in 1 ml into the prostate under ultrasound guidance. Ganciclovir was then given intravenously for 14 days (5 mg/kg every 12 hr). Patients were monitored closely for evidence of toxicity and for response to therapy. Eighteen patients were treated at 4 escalating doses: group 1 (n = 4) received 1 x 10(8) infectious units (IU); group 2 (n = 5) received 1 x 10(9) IU; group 3 (n = 4) received 1 x 10(10) IU; group 4 (n = 5) received 1 x 10(11) IU. Vector was detected by PCR of urine samples after treatment, increasing in frequency and duration (up to 32 days) as the dose increased. All cultures of blood and urine specimens were negative for growth of adenovirus. Minimal toxicity (grade 1-2) was encountered in four patients. One patient at the highest dose level developed spontaneously reversible grade 4 thrombocytopenia and grade 3 hepatotoxicity. Three patients achieved an objective response, one each at the three highest dose levels, documented by a fall in serum PSA levels by 50% or more, sustained for 6 weeks to 1 year. This study is the first to demonstrate the safety of ADV/HSV-tk plus GCV gene therapy in human prostate cancer and the first to demonstrate anticancer activity of gene therapy in patients with prostate cancer. Further trials are underway to identify the optimal distribution of vector within the prostate and to explore the safety of repeat courses of gene therapy.

The neurotoxicity of an adenoviral vector (Adv.RSVtk) carrying the gene for herpes simplex virus thymidine kinase (HSVtk) was tested in the cotton rat, a semipermissive host. Adv.RSVtk was injected intracerebrally in cotton rats at a dose of 5.0 x 10(6) or 7.5 x 10(7) p.f.u. No signs of illness were observed. Histological inspection at 12 and 28 days after injection showed inflammation of the ependyma and choroid plexus and at the injection site. No demyelination, viral inclusions, cerebral edema, necrosis, cavities or vascular necrosis were seen in the brains. There was no significant difference between animals injected with 5.0 x 10(6) or 7.5 x 10(7) p.f.u., nor was there a difference between animals analyzed at 12 or 28 days after vector injection. This inflammation was similar in animals that had been preimmunized with wild-type virus and in animals that had been treated with ganciclovir. No histopathology, was observed in the lungs of the animals and no replication-competent virus was detected. These experiments indicate that Adv.RSVtk has limited neurotoxicity which would not prohibit its use in a limited phase I clinical trial in humans that have malignant tumors of the central nervous system.

A phase I-II study to evaluate gene-mediated cytotoxic immunotherapy in newly diagnosed prostate cancer before radical prostatectomy was conducted in Monterrey, Mexico. First, to investigate delivery of adenovirus to the prostate, fluorescently labeled vector was injected into fresh prostatectomy specimens and distribution was visually analyzed. The optimal volume and site instillation was then used for transrectal ultrasound guided intraprostatic injection in 10 patients with adenocarcinoma scheduled for radical prostatectomy. Each received two apical and two basal 0.5 ml injections of AdV-tk for a total of 1 × 10(11) vp followed by 14 days of prodrug. Nine patients continued to tumor resection: six high risk, one intermediate and two low risk. In vivo vector distribution was analyzed from the resected tissue of four patients. Patients were monitored for tumor progression and acute and long-term safety. For vector delivery, two apical and two basal injections of 0.5 ml led to optimal organ-wide distribution ex vivo and in vivo. Cytotoxicity was evidenced by transient rise in PSA and tumor histology. There were no significant adverse events deemed related to the treatment and no late toxicities after median follow-up of 11.3 years. All six high-risk patients had positive surgical margins and one had seminal vesicle involvement. Despite slow PSA rise post surgery in three of these patients, none developed metastases. The intermediate- and low-risk patients had complete resections and none have progressed. In conclusion, in vivo transrectal ultrasound guided instillation of an adenoviral vector into four sites in the prostate was practical as an outpatient procedure, well tolerated and led to distribution throughout the intraprostatic tumor mass. AdV-tk demonstrated no significant acute or late toxicities. Trends in PSA and disease progression conveyed the possibility of a sustained immune response against residual disease.