RNA Activation-A Novel Approach to Therapeutically Upregulate Gene Transcription.

RNA activation (RNAa) is a mechanism whereby RNA oligos complementary to genomic sequences around the promoter region of genes increase the transcription output of their target gene. Small activating RNA (saRNA) mediate RNAa through interaction with protein co-factors to facilitate RNA polymerase II activity and nucleosome remodeling. As saRNA are small, versatile and safe, they represent a new class of therapeutics that can rescue the downregulation of critical genes in disease settings. This review highlights our current understanding of saRNA biology and describes various examples of how saRNA are successfully used to treat various oncological, neurological and monogenic diseases. MTL-CEBPA, a first-in-class compound that reverses CEBPA downregulation in oncogenic processes using CEBPA-51 saRNA has entered clinical trial for the treatment of hepatocellular carcinoma (HCC). Preclinical models demonstrate that MTL-CEBPA reverses the immunosuppressive effects of myeloid cells and allows for the synergistic enhancement of other anticancer drugs. Encouraging results led to the initiation of a clinical trial combining MTL-CEBPA with a PD-1 inhibitor for treatment of solid tumors.

MTL-CEBPA, a Small Activating RNA Therapeutic Upregulating C/EBP-α, in Patients with Advanced Liver Cancer: A First-in-Human, Multicenter, Open-Label, Phase I Trial.

PURPOSE: Transcription factor C/EBP-α (CCAAT/enhancer-binding protein alpha) acts as a master regulator of hepatic and myeloid functions and multiple oncogenic processes. MTL-CEBPA is a first-in-class small activating RNA oligonucleotide drug that upregulates C/EBP-α. PATIENTS AND METHODS: We conducted a phase I, open-label, dose-escalation trial of MTL-CEBPA in adults with advanced hepatocellular carcinoma (HCC) with cirrhosis, or resulting from nonalcoholic steatohepatitis or with liver metastases. Patients received intravenous MTL-CEBPA once a week for 3 weeks followed by a rest period of 1 week per treatment cycle in the dose-escalation phase (3+3 design). RESULTS: Thirty-eight participants have been treated across six dose levels (28-160 mg/m2) and three dosing schedules. Thirty-four patients were evaluable for safety endpoints at 28 days. MTL-CEBPA treatment-related adverse events were not associated with dose, and no maximum dose was reached across the three schedules evaluated. Grade 3 treatment-related adverse events occurred in nine (24%) patients. In 24 patients with HCC evaluable for efficacy, an objective tumor response was achieved in one patient [4%; partial response (PR) for over 2 years] and stable disease (SD) in 12 (50%). After discontinuation of MTL-CEBPA, seven patients were treated with tyrosine kinase inhibitors (TKIs); three patients had a complete response with one further PR and two with SD. CONCLUSIONS: MTL-CEBPA is the first saRNA in clinical trials and demonstrates an acceptable safety profile and potential synergistic efficacy with TKIs in HCC. These encouraging phase I data validate targeting of C/EBP-α and have prompted MTL-CEBPA + sorafenib combination studies in HCC.

Liver Activation of Hepatocellular Nuclear Factor-4α by Small Activating RNA Rescues Dyslipidemia and Improves Metabolic Profile.

Non-alcoholic fatty liver disease (NAFLD) culminates in insulin resistance and metabolic syndrome. Because there are no approved pharmacological treatment agents for non-alcoholic steatohepatitis (NASH) and NAFLD, different signaling pathways are under investigation for drug development with the focus on metabolic pathways. Hepatocyte nuclear factor 4-alpha (HNF4A) is at the center of a complex transcriptional network where its disruption is directly linked to glucose and lipid metabolism. Resetting HNF4A expression in NAFLD is therefore crucial for re-establishing normal liver function. Here, small activating RNA (saRNA) specific for upregulating HNF4A was injected into rats fed a high-fat diet for 16 weeks. Intravenous delivery was carried out using 5-(G5)-triethanolamine-core polyamidoamine (PAMAM) dendrimers. We observed a significant reduction in liver triglyceride, increased high-density lipoprotein/low-density lipoprotein (HDL/LDL) ratio, and decreased white adipose tissue/body weight ratio, all parameters to suggest that HNF4A-saRNA treatment induced a favorable metabolic profile. Proteomic analysis showed significant regulation of genes involved in sphingolipid metabolism, fatty acid ß-oxidation, ketogenesis, detoxification of reactive oxygen species, and lipid transport. We demonstrate that HNF4A activation by oligonucleotide therapy may represent a novel single agent for the treatment of NAFLD and insulin resistance.

Intra-Arterial Immunoselected CD34+ Stem Cells for Acute Ischemic Stroke.

Treatment with CD34+ hematopoietic stem/progenitor cells has been shown to improve functional recovery in nonhuman models of ischemic stroke via promotion of angiogenesis and neurogenesis. We aimed to determine the safety and feasibility of treatment with CD34+ cells delivered intra-arterially in patients with acute ischemic stroke. This was the first study in human subjects. We performed a prospective, nonrandomized, open-label, phase I study of autologous, immunoselected CD34+ stem/progenitor cell therapy in patients presenting within 7 days of onset with severe anterior circulation ischemic stroke (National Institutes of Health Stroke Scale [NIHSS] score≥8). CD34+ cells were collected from the bone marrow of the subjects before being delivered by catheter angiography into the ipsilesional middle cerebral artery. Eighty-two patients with severe anterior circulation ischemic stroke were screened, of whom five proceeded to treatment. The common reasons for exclusion were age>80 years (n=19); medical instability (n=17), and significant carotid stenosis (n=13). The procedure was well tolerated in all patients, and no significant treatment-related adverse effects occurred. All patients showed improvements in clinical functional scores (Modified Rankin Score and NIHSS score) and reductions in lesion volume during a 6-month follow-up period. Autologous CD34+ selected stem/progenitor cell therapy delivered intra-arterially into the infarct territory can be achieved safely in patients with acute ischemic stroke. Future studies that address eligibility criteria, dosage, delivery site, and timing and that use surrogate imaging markers of outcome are desirable before larger scale clinical trials.

Exploiting human CD34+ stem cell-conditioned medium for tissue repair.

Despite the progress in our understanding of genes essential for stem cell regulation and development, little is known about the factors secreted by stem cells and their effect on tissue regeneration. In particular, the factors secreted by human CD34+ cells remain to be elucidated. We have approached this challenge by performing a cytokine/growth factor microarray analysis of secreted soluble factors in medium conditioned by adherent human CD34+ cells. Thirty-two abundantly secreted factors have been identified, all of which are associated with cell proliferation, survival, tissue repair, and wound healing. The cultured CD34+ cells expressed known stem cell genes such as Nanog, Oct4, Sox2, c-kit, and HoxB4. The conditioned medium containing the secreted factors prevented cell death in liver cells exposed to liver toxin in vitro via inhibition of the caspase-3 signaling pathway. More importantly, in vivo studies using animal models of liver damage demonstrated that injection of the conditioned medium could repair damaged liver tissue (significant reduction in the necroinflammatory activity), as well as enable the animals to survive. Thus, we demonstrate that medium conditioned by human CD34+ cells has the potential for therapeutic repair of damaged tissue in vivo.

Novel RNA oligonucleotide improves liver function and inhibits liver carcinogenesis in vivo.

UNLABELLED: Hepatocellular carcinoma (HCC) occurs predominantly in patients with liver cirrhosis. Here we show an innovative RNA-based targeted approach to enhance endogenous albumin production while reducing liver tumor burden. We designed short-activating RNAs (saRNA) to enhance expression of C/EBPα (CCAAT/enhancer-binding protein-α), a transcriptional regulator and activator of albumin gene expression. Increased levels of both C/EBPα and albumin mRNA in addition to a 3-fold increase in albumin secretion and 50% decrease in cell proliferation was observed in C/EBPα-saRNA transfected HepG2 cells. Intravenous injection of C/EBPα-saRNA in a cirrhotic rat model with multifocal liver tumors increased circulating serum albumin by over 30%, showing evidence of improved liver function. Tumor burden decreased by 80% (P = 0.003) with a 40% reduction in a marker of preneoplastic transformation. Since C/EBPα has known antiproliferative activities by way of retinoblastoma, p21, and cyclins, we used messenger RNA (mRNA) expression liver cancer-specific microarray in C/EBPα-saRNA-transfected HepG2 cells to confirm down-regulation of genes strongly enriched for negative regulation of apoptosis, angiogenesis, and metastasis. Up-regulated genes were enriched for tumor suppressors and positive regulators of cell differentiation. A quantitative polymerase chain reaction (PCR) and western blot analysis of C/EBPα-saRNA-transfected cells suggested that in addition to the known antiproliferative targets of C/EBPα, we also observed suppression of interleukin (IL)6R, c-Myc, and reduced STAT3 phosphorylation. CONCLUSION: A novel injectable saRNA-oligonucleotide that enhances C/EBPα expression successfully reduces tumor burden and simultaneously improves liver function in a clinically relevant liver cirrhosis/HCC model.

A Short-activating RNA Oligonucleotide Targeting the Islet ß-cell Transcriptional Factor MafA in CD34(+) Cells.

Upon functional loss of insulin producing islet ß-cells, some patients with diabetes become dependent on life-long insulin supplementation therapy. Bioengineering surrogate insulin producing cells is an alternative replacement strategy. We have developed a novel approach using short-activating RNA oligonucleotides to differentiate adult human CD34(+) cells into insulin-secreting cells. By transfecting RNA to increase transcript levels of the master regulator of insulin biosynthesis, v-maf musculoaponeurotic fibrosarcoma oncogene homolog A (MafA), several pancreatic endodermal genes were upregulated during the differentiation procedure. These included Pancreatic and duodenal homeobox gene-1 (PDX1), Neurogenin 3, NeuroD, and NK6 homeobox 1 (NKx6-1). Differentiated CD34(+) cells also expressed glucokinase, glucagon-like peptide 1 receptor (GLP1R), sulfonylurea receptor-1 (SUR1) and phogrin-all essential for glucose sensitivity and insulin secretion. The differentiated cells appropriately processed C-peptide and insulin in response to increasing glucose stimulation as shown by enzyme-linked immunosorbent assay (ELISA), fluorescence-activated cell sorting analysis, western blotting, and immunofluorescence staining. We provide a new approach using short-activating RNA in developing insulin producing surrogate cells for treating diabetes.Molecular Therapy - Nucleic Acids (2013) 2, e97; doi:10.1038/mtna.2013.23; advance online publication 4 June 2013.

Habib EndoHPB: a novel endobiliary radiofrequency ablation device. An experimental study.

BACKGROUND: The Habib EndoHPB is a bipolar radiofrequency (RF) catheter developed to be introduced across malignant strictures of the bile ducts, so that RF energy can locally ablate the tumor prior to stent placement. This experiment aims to assess the ability of the catheter to coagulate the wall of the common bile duct (CBD) in a porcine model, to establish power requirement and time parameters and correlate them to the depth of thermal injury, and to assess the ease of operation of the device. METHODS: The CBD was catheterized using the device in 20 pigs. RF energy was applied to the CBD wall with various generator settings. The pigs were sacrificed 24 hr after the application and the CBD was excised for histological analysis. RESULTS: The device was easy to handle. Statistically significant correlations between the power, the time of RF application, and the thermal injury depth were found. CONCLUSION: The Habib EndoHPB catheter can effectively deliver RF energy intraluminally in the porcine CBD. Clinical studies are warranted in order to define proper settings for safe and efficient use in malignant biliary obstruction.

Novel percutaneous radiofrequency ablation of portal vein tumor thrombus: safety and feasibility.

PURPOSE: We report our experience of the safety of partial recanalization of the portal vein using a novel endovascular radiofrequency (RF) catheter for portal vein tumor thrombosis. METHODS: Six patients with liver cancer and tumor thrombus in the portal vein underwent percutaneous intravascular radiofrequency ablation (RFA) using an endovascular bipolar RF device. A 0.035-inch guidewire was introduced into a tributary of the portal vein and through which a 5G guide catheter was introduced into the main portal vein. After manipulation of the guide catheter over the thrombus under digital subtraction angiography, the endovascular RF device was inserted and activated around the thrombus. RESULTS: There were no observed technique specific complications, such as hemorrhage, vessel perforation, or infection. Post-RFA portography showed partial recanalization of portal vein. CONCLUSIONS: RFA of portal vein tumor thrombus in patients with hepatocellular carcinoma is technically feasible and warrants further investigation to assess efficacy compared with current recanalization techniques.

Percutaneous intraductal radiofrequency ablation is a safe treatment for malignant biliary obstruction: feasibility and early results.

PURPOSE: Previous clinical studies have shown the safety and efficacy of this novel radiofrequency ablation catheter when used for endoscopic palliative procedures. We report a retrospective study with the results of first in man percutaneous intraductal radiofrequency ablation in patients with malignant biliary obstruction. METHODS: Thirty-nine patients with inoperable malignant biliary obstruction were included. These patients underwent intraductal biliary radiofrequency ablation of their malignant biliary strictures following external biliary decompression with an internal-external biliary drainage. Following ablation, they had a metal stent inserted. RESULTS: Following this intervention, there were no 30-day mortality, hemorrhage, bile duct perforation, bile leak, or pancreatitis. Of the 39 patients, 28 are alive and 10 patients are dead with a median survival of 89.5 (range 14-260) days and median stent patency of 84.5 (range 14-260) days. One patient was lost to follow-up. All but one patient had their stent patent at the time of last follow-up or death. One patient with stent blockage at 42 days postprocedure underwent percutaneous transhepatic drain insertion and restenting. Among the patients who are alive (n = 28) the median stent patency was 92 (range 14-260) days, whereas the patients who died (n = 10) had a median stent patency of 62.5 (range 38-210) days. CONCLUSIONS: In this group of patients, it appears that this new approach is feasible and safe. Efficacy remains to be proven in future, randomized, prospective studies.

MicroRNA-181a* Targets Nanog in a Subpopulation of CD34(+) Cells Isolated From Peripheral Blood.

Exploiting the properties of stem cells by microRNA (miRNA) profiling offers an attractive approach to identify new regulators of stem cell fate. Although numerous miRNA have been screened from hematopoietic stem cells (HSC), the targets corresponding to many of these miRNA have not yet been fully elucidated. By miRNA profiling in a subpopulation of CD34+ cells isolated from peripheral blood, we have identified eight clusters of miRNA that were differentially expressed. Further analysis of one of the clusters by bioinformatics revealed that a miRNA, miR-181a*, which is highly expressed in the adherent CD34+ cells, affects the expression levels of Nanog, a stem cell surrogate marker. We show specifically by reporter assay and mutational analysis that miR-181a* targets a seedless 3' compensatory site in the 3'UTR of Nanog and affects gene expression. We demonstrate that inhibiting miR-181a* upregulates the Nanog expression level, in addition to an increase in alkaline phosphatase activity. Our studies suggest that miR-181a* may be important in controlling the expression level of Nanog in a subpopulation of CD34+ cells.

A perspective on non-catalytic Src homology (SH) adaptor signalling proteins.

Intracellular adaptor signalling proteins are members of a large family of mediators crucial for signal transduction pathways. Structurally, these molecules contain one Src Homology 2 (SH2) domain and one or more Src Homology 3 (SH3) domain(s); with either a catalytic subunit, or with other non-catalytic modular subunits. Cells depend on these regulatory signalling molecules to transmit information to the nucleus from both external and internal cues including growth factors, cytokines and steroids. Although there is a vast library of adaptor signalling proteins expressed ubiquitously in cells, the vital role these SH containing proteins play in regulating cellular signalling lacks the recognition they deserve. Their target selection method via the SH domains is simple yet highly effective. The SH3 domain(s) interact with proteins that contain proline-rich motifs, whereas the SH2 domain only binds to proteins containing phosphotyrosine residues. This unique characteristic physically enables proteins from a diverse range of networks to assemble for amplification of a signalling event. The biological consequence generated from these adaptor signalling proteins in a constantly changing microenvironment have profound regulatory effect on cell fate decision particularly when this is involved in the progression of a diseased state.

Endoscopically applied radiofrequency ablation appears to be safe in the treatment of malignant biliary obstruction.

BACKGROUND: In unresectable malignant bile duct obstruction in a patient with a life expectancy longer than 3 months, the use of self-expandable metal stents (SEMSs) is the standard technique to ensure continued biliary drainage. As many as 50% of patients with SEMSs will present with stent occlusion within 6 months. Changes to stent design and composition and concomitant therapy have failed to improve stent patency; therefore, alternative techniques to safely prolong stent patency are required. OBJECTIVE: To demonstrate the safety of endobiliary bipolar radiofrequency ablation (RFA) in patients with malignant biliary obstruction and to report the 90-day biliary patency of this novel procedure. DESIGN: Open-label pilot study. SETTING: Single tertiary care unit. PATIENTS: A total of 22 patients with unresectable malignant bile duct obstruction. INTERVENTIONS: Bipolar RFA within the bile duct. MAIN OUTCOME MEASUREMENTS: Immediate and 30-day complications and 90-day stent patency. RESULTS: A total of 22 patients (16 pancreatic, 6 cholangiocarcinoma) were recruited between January 2009 and April 2010. Deployment of an RFA catheter was successful in 21 patients. SEMS placement was achieved in all cases of successful RFA catheter deployment. One patient failed to demonstrate successful biliary decompression after SEMS placement and died within 90 days. All other patients maintained stent patency at 30 days. One patient had asymptomatic biochemical pancreatitis, 2 patients required percutaneous gallbladder drainage, and 1 patient developed rigors. At 90-day follow-up, 1 additional patient had died with a patent stent, and 3 patients had occluded biliary stents. LIMITATIONS: Cohort study. CONCLUSIONS: Endobiliary RFA treatment appears to be safe. Randomized studies with prolonged follow-up are warranted.

Pilot study for a new bipolar radiofrequency ablation/aspirator device in the management of primary and secondary liver cancers.

BACKGROUND: In the US, the thermal ablation workload for cancer involving the liver is predicted to more than double in the next 5 years, emphasising the need to develop and improve the current technology. STUDY DESIGN: A multicentre nonrandomised prospective clinical trial (NCT00514930) was undertaken, to assess the efficacy and safety of a new bipolar radiofrequency ablation/aspirator device, in the treatment of primary and secondary cancers of the liver. RESULTS: A total of 34 lesions in 16 patients were ablated at laparotomy and followed up at 4 weeks. The mean diameter of lesion before ablation was 3.2+/-2.22 (range 1-10) cm, the mean volume aspirated during ablation was 9.25+/-7.3 (range 0-25) ml and the mean operative time was 145.95+/-40.7 (range 60-215) min. There was one major complication of a pleural effusion, which required drainage. The mean length of stay was 8+/-3.2 (range 3-14) days. In 11 patients, the ablated tumour was resected. On histological assessment, there was no evidence of viable cancer at the tumour edge. On follow-up computed tomography, the ablation zone fully encompassed the targeted tumour and there were no local complications related to ablation. CONCLUSION: Initial analysis of the data from this small cohort, with only a short-term follow-up, shows this device to be safe and effective.

Repeat hepatic resection using a radiofrequency-assisted technique.

BACKGROUND: Repeat hepatic resection for recurrent primary or secondary liver cancer is performed due to advances in resection techniques and evidence of survival benefit. This paper presents the safety and efficacy of repeat radiofrequency-assisted hepatic resection to highlight the utility of the technique. METHODS: 264 consecutive hepatic resections performed on 218 patients were identified. The subset of patients with recurrent disease (n = 24) suitable for repeat hepatic resection had their records reviewed. RESULTS: Including initial (n = 24), second (n = 24) and third hepatic resection (n = 6), a total of 54 hepatic resections were performed in 24 patients. Non-anatomical resection in the form of metastasectomy was the most common procedure. There were no post-operative deaths. Four patients (17%) had complications after their second resection and 1 (17%) after the third resection. There were no cases of bile leak or liver failure. The proportion of repeat hepatic resection for recurrent disease was high: 50% of recurrences were suitable for further resection after initial resection and 43% after second resection. CONCLUSION: Radiofrequency-assisted repeat hepatic resection is a safe procedure and may increase the proportion of patients who can be considered for a curative repeat hepatic resection.

Autologous infusion of expanded mobilized adult bone marrow-derived CD34+ cells into patients with alcoholic liver cirrhosis.

OBJECTIVES: Recent advances in regenerative medicine, including hematopoietic stem cell (HSC) transplantation, have brought hope for patients with severe alcoholic liver cirrhosis (ALC). The aim of this study was to assess the safety and efficacy of administering autologous expanded mobilized adult progenitor CD34+ cells into the hepatic artery of ALC patients and the potential improvement in the liver function. METHODS: Nine patients with biopsy-proven ALC, who had abstained from alcohol for at least 6 months, were recruited into the study. Following granulocyte colony-stimulating factor (G-CSF) mobilization and leukapheresis, the autologous CD34+ cells were expanded in vitro and injected into the hepatic artery. All patients were monitored for side effects, toxicities, and changes in the clinical, hematological, and biochemical parameters. RESULTS: On average, a five-fold expansion in cell number was achieved in vitro, with a mean total nucleated cell count (TNCC) of 2.3 x 10(8) pre infusion. All patients tolerated the procedure well, and there were no treatment-related side effects or toxicities observed. There were significant decreases in serum bilirubin (P < 0.05) 4, 8, and 12 wk post infusion. The levels of alanine transaminase (ALT) and aspartate transaminase (AST) showed improvement through the study period and were significant (P < 0.05) 1 wk post infusion. The Child-Pugh score improved in 7 out of 9 patients, while 5 patients had improvement in ascites on imaging. CONCLUSION: It is safe to mobilize, expand, and reinfuse autologous CD34+ cells in patients with ALC. The clinical and biochemical improvement in the study group is encouraging and warrants further clinical trials.

Liver resection with a new multiprobe bipolar radiofrequency device.

HYPOTHESIS: Liver resection can be associated with marked blood loss. A novel multiprobe bipolar radiofrequency device (Habib 4X; RITA Medical Systems Inc, Fremont, California) has been developed to assist in liver resection and to reduce intraoperative blood loss. DESIGN: Prospective study. SETTING: Tertiary referral unit. PATIENTS: Sixty-two patients requiring liver resection between November 1, 2004, and February 28, 2006, primarily for metastatic cancer. INTERVENTION: Liver resection with the radiofrequency device. MAIN OUTCOME MEASURES: Intraoperative blood loss, liver parenchyma transection time, and complications. RESULTS: There were 51 minor and 11 major hepatectomies. Mean (SD) transection time was 39 (27) seconds per square centimeter. Mean (SD) blood loss was 4.8 (5.6) mL per square centimeter. No patient required hepatic inflow occlusion. One patient required blood transfusion. There were no deaths, and the morbidity rate was 18%. Mean (SD) hospital stay was 8 (3) days. CONCLUSIONS: This new bipolar radiofrequency device allows minor and major hepatectomies to be performed with minimal blood loss, low blood transfusion requirement, and reduced mortality and morbidity rates.

High frequency of fetal cells within a primitive stem cell population in maternal blood.

BACKGROUND: During pregnancy, fetal cells enter the maternal bloodstream resulting in fetal cell microchimerism. The fetal cells persist in the mother for decades and colonize a variety of maternal organs. They are associated with maternal autoimmune diseases and may also participate in tissue repair. The identity of the microchimeric cells is not certain but they must be able to persist long-term and have potential for multitissue differentiation. METHODS AND RESULTS: Here we tested the hypothesis that the fetal microchimeric cells are primitive stem cells, represented by CD34+ adherent cells, which have a wide potential for differentiation. We isolated these stem cells from the blood of pregnant females (n = 25) and detected fetal cells of the correct gender, using fluorescence in situ hybridization, in a high proportion (71% male fetuses and 90% female fetuses; false positive rate 11%, false negative rate 29%) of cases. By RT-PCR, we demonstrated that the cells express Oct-4, Nanog and Rex-1. No fetal cells were detected in the mononuclear or total CD34+ cell populations but high frequencies (mean 11.8%) of fetal cells were detected in the adherent CD34+ cell population. CONCLUSIONS: These results identify adherent CD34+ stem cells as candidate fetal microchimeric cells, which are capable of sustaining the fetal cell population in the long term and have the ability to colonize multiple tissues and organs.

Vaccination of colorectal cancer patients with modified vaccinia ankara encoding the tumor antigen 5T4 (TroVax) given alongside chemotherapy induces potent immune responses.

PURPOSE: The attenuated strain of vaccinia virus, modified vaccinia Ankara (MVA) encoding the tumor antigen 5T4 (TroVax), has been evaluated in an open-label phase II study in metastatic colorectal cancer patients. The primary objective was to assess the safety and immunogenicity of TroVax injected before, during, and after treatment with cycles of 5-fluorouracil, folinic acid, and oxaliplatin. EXPERIMENTAL DESIGN: TroVax was administered to 17 patients with metastatic colorectal cancer. In total, 11 patients were considered to be evaluable for assessment of immunologic responses having received a total of six injections of TroVax, administered before, during, and following completion of chemotherapy. Antibody and cellular responses specific for 5T4 and MVA were monitored throughout the study. RESULTS: Administration of TroVax alongside 5-fluorouracil, folinic acid, and oxaliplatin was safe and well tolerated with no serious adverse events attributed to TroVax. Ten of the 11 evaluable patients mounted 5T4-specific antibody responses with titers ranging from 10 to >1,000. IFNgamma enzyme-linked immunospot responses specific for 5T4 were detected in 10 patients with precursor frequencies exceeding 1 in 1,000 peripheral blood mononuclear cells in 4 patients. Of the 11 evaluable patients, 6 had complete or partial responses. 5T4-specific immune responses, but not MVA-specific immune responses, correlated with clinical benefit. CONCLUSIONS: Potent 5T4-specific cellular and/or antibody responses were induced in all evaluable patients and were still detectable during the period in which chemotherapy was administered. These results suggest that TroVax can be added to chemotherapy regimens without any evidence of enhanced toxicity or reduced immunologic efficacy and may provide additional clinical benefit.

Induction of tumor-specific T-cell responses by vaccination with tumor lysate-loaded dendritic cells in colorectal cancer patients with carcinoembryonic-antigen positive tumors.

BACKGROUND: Dendritic cells (DCs) are the most effective antigen-presenting cells. In the last decade, the use of DCs for immunotherapy of cancer patients has been vastly increased. High endocytic capacity together with a unique capability of initiating primary T-cell responses have made DCs the most potent candidates for this purpose. Although DC vaccination occasionally leads to tumor regression, clinical efficacy, and immunogenicity of DCs in clinical trials has not been yet clarified. The present study evaluated the safety and effectiveness of tumor-lysate loaded DC vaccines in advanced colorectal cancer (CRC) patients with carcinoembryonic antigen (CEA) positive tumors. RESULTS: Six patients HLA-A*0201-positive were vaccinated with autologous DCs loaded with tumor lysates (TL) together with tetanus toxoid antigen, hepatitis B, and influenza matrix peptides. Two additional patients were injected with DCs that were generated from their sibling or parent with one haplotype mismatch. All patients received the vaccines every 2 weeks, with a total of three intra-nodal injections per patient. The results indicated that DC vaccination was safe and well tolerated by the patients. Specific immune responses were detected and in some patients, transient stabilization or even reduction of CEA levels were observed. The injection of haplotype mismatched HLA-A*0201-positive DCs resulted in some enhancement of the anti-tumor response in vitro and led to stabilization/reduction of CEA levels in the serum, compared to the use of autologous DCs. CONCLUSION: Altogether, these results suggest that TL-pulsed DCs may be an effective vaccine method in CRC patients. Elimination of regulatory mechanisms as well as adjustment of the vaccination protocol may improve the efficacy of DC vaccination.