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Y Fong

Publications and source records attributed to Y Fong.

At least 37 records · Page 2Linked to original sources
PubMed2001

Hepatocellular carcinoma: current surgical management.

At present the only potentially curative treatment for hepatocellular carcinoma (HCC) is either partial hepatectomy or total hepatectomy with orthotopic liver transplantation (OLT). Underlying liver reserve and regenerative capacity are the most important determinants of the risk of postoperative hepatic failure after partial hepatectomy; thus, careful preoperative assessment of liver function is mandatory. In specialized centers perioperative mortality is less than 5%, although cirrhotic patients are at increased risk. Various neoadjuvant and adjuvant therapies are under investigation, but as yet there are no data that demonstrate benefit from adjuvant systemic chemotherapy. The use of OLT is limited by the difficulty of obtaining donor livers. Patients selected for transplantation and partial hepatectomy represent two distinct subgroups, but their survival after treatment is comparable. Despite the progress in the management of HCC by surgical resection, the fact remains that the majority of these patients will experience local recurrences. This has led to the development of a variety of novel new treatments that require further evaluation.

Carcinoma, Hepatocellular↗
PubMed2001

Extended hepatic resection: a 6-year retrospective study of risk factors for perioperative mortality.

BACKGROUND: Extended hepatic resection (more than four liver segments) is a major operative procedure that is associated with significant risk. The purpose of this study was to assess the impact of perioperative variables on in-hospital mortality after extended hepatectomy. STUDY DESIGN: Consecutive patients who underwent extended hepatic resection were studied. The prognostic value of 29 perioperative variables was evaluated using in-hospital mortality as the endpoint. For each variable, the odds ratio (95% confidence interval) for in-hospital mortality was calculated. Those variables with a lower confidence limit > 1 were considered important risk factors. The population was stratified into categories of patients having the same number of risk factors, and mortality was estimated for each group. These data were used to develop a risk assessment algorithm. RESULTS: There were 14 deaths (6%) in 226 patients. Three preoperative variables (cholangitis, creatinine > 1.3 mg/dL, and total bilirubin > 6 mg/dL) and two operative variables (blood loss > 3 L and vena caval resection) appear to be important factors for in-hospital mortality. The mortality associated with the presence of any two of the five factors was 100% (5 of 5), and the mortality associated with the absence of these factors was 3% (6 of 191). CONCLUSIONS: Perioperative evaluation of patients undergoing extended hepatic resection should include the quantitation of mortality risk factors. The combination of any two factors among preoperative cholangitis, elevated serum creatinine, elevated serum bilirubin, high operative blood loss, and vena cava resection may carry a high mortality risk. These results require prospective validation.

Adolescent↗
PubMed2001

What is the yield of intraoperative ultrasonography during partial hepatectomy for malignant disease?

BACKGROUND: Previous studies have shown that intraoperative ultrasonography (IOUS) during hepatic resection for malignancy changes the operative plan or identifies occult unresectable disease in a large proportion of patients. This study was undertaken to reassess the yield of IOUS in light of recent improvements in preoperative staging. STUDY DESIGN: Patients with potentially resectable primary or metastatic hepatic malignancies subjected to exploration, bimanual palpation of the liver, and IOUS were evaluated prospectively. Intraoperative findings were recorded, and preoperative imaging studies were reanalyzed by radiologists blinded to the intraoperative findings. The extent of disease based on preoperative imaging was compared with the intraoperative findings. RESULTS: From October 1997 until November 1998, 111 patients were evaluated. At exploration, a total of 77 new findings or findings different than suggested on the imaging studies were identified in 61 patients (55%), the most common of which was additional hepatic tumors (n = 37). Thirty-five of 77 (45%) new findings were identified by IOUS alone and 10 (13%) by palpation alone; the remainder were identified by both palpation and IOUS. Forty-seven of 61 patients (77%) underwent a complete resection despite new intraoperative findings, with a modification (n = 28) or no change (n = 19) in the planned operation. Twenty-one patients (19%) had new findings identified only on IOUS. Thirteen of these patients underwent resection with no change in the operative plan, six underwent a modified resection and two were considered to have unresectable disease based solely on the findings of IOUS. CONCLUSIONS: In patients with hepatic malignancies submitted to a potentially curative resection, new intraoperative findings or findings different than suggested on preoperative imaging studies are common. But resection with no change in the operative plan or a modified resection is still possible in the majority of patients despite such findings. The findings on IOUS alone rarely lead to a change in the operative plan.

Aged↗
PubMed2001

Effective treatment of head and neck squamous cell carcinoma by an oncolytic herpes simplex virus.

BACKGROUND: The prognosis of patients with advanced or recurrent head and neck squamous cell carcinoma remains poor despite refinements in multimodality therapies. This study evaluates the efficacy of a replication-competent, attenuated, oncolytic herpes simplex virus, NV1020, as a novel agent in the treatment of human head and neck squamous cell carcinoma (HNSCC). STUDY DESIGN: Five different HNSCC lines were exposed to NV1020 in vitro at varying viral concentrations. The ability of the virus to lyse and replicate within these cancer cells in vitro was determined by cytotoxicity assay and plaque assay, respectively. Three HNSCC lines were grown in the subcutaneous flanks of athymic nude mice and treated with an intratumoral injection of NV1020 or saline as a control. Tumor dimensions were subsequently measured at serial time points and tumor volumes were calculated. Herpes simplex virus (HSV)-1 immunohistochemistry was performed on excised tumors to determine the efficacy of in vivo tumor infection by NV1020. RESULTS: NV1020 was highly cytotoxic in vitro to all five human HNSCC lines at a concentration of one infectious viral particle per cancer cell, and had variable cytotoxicity at a 100-fold lower concentration. Viral replication in vitro by NV1020 was efficient in four of five HNSCC lines with a greater than 200-fold increase in viral titers. Flank tumors treated with intratumoral injections of NV1020 resulted in significant regression of all tested HNSCC lines. HSV-1 immunohistochemistry of excised flank tumors treated with NV1020 demonstrated positive cytoplasmic staining and areas of tumor necrosis at 24 hours after injection. CONCLUSIONS: NV1020 is an oncolytic HSV that displays efficient replication and oncolysis in human HNSCC lines in vitro. Injection of NV1020 into murine flank tumors demonstrated effective tumor regression. Treatment of HNSCC with NV1020 is a promising form of therapy with potential clinical applicability in humans.

Animals↗
PubMed2001

Intrahepatic cholangiocarcinoma: resectability, recurrence pattern, and outcomes.

Intrahepatic cholangiocarcinoma (IHC) is a rare primary hepatic tumor of bile duct origin for which resection is the most effective treatment. But resectability, outcomes after resection, and recurrence patterns have not been well described. Patients with IHC were identified from a prospective database. Demographic data, tumor characteristics, and outcomes were analyzed. From March 1992 to September 2000, 53 patients with hepatic tumors underwent exploration and were found to have pure IHC on pathologic analysis. Patients with mixed hepatocellular and cholangiocarcinoma tumors were excluded. At exploration, 20 patients were unresectable for an overall resectability rate of 62% (33 of 53). Median survival for patients submitted to resection was 37.4 months versus 11.6 months for patients undergoing biopsy only (p = 0.006; median followup for surviving patients, 15.6 months). Actuarial 3-year survival was 55% versus 21%, respectively. Factors predictive of poor survival after resection included vascular invasion (p = 0.0007), histologically positive margin (p = 0.009), or multiple tumors (p = 0.003). After resection, 20 of 33 patients (61%) recurred at a median of 12.4 months. Sites of recurrence included the liver (14), retroperitoneal or hilar nodes (4), lung (4), and bone (2). The median disease-free survival was 19.4 months, with a 3-year disease-free survival rate of 22%. Factors predictive of recurrence were multiple tumors (p = 0.0002), tumor size (p = 0.001), and vascular invasion (p = 0.01). About two-thirds of patients who appeared resectable on preoperative imaging were amenable to curative resection at the time of operation. Although complete resection improved survival, recurrence was common. The majority of recurrences were local or regional, which may help guide future adjuvant therapy strategies.

Actuarial Analysis↗
PubMed2001

Peritoneal washings are not predictive of occult peritoneal disease in patients with hilar cholangiocarcinoma.

BACKGROUND: Evaluation of peritoneal cytology provides valuable staging information in patients with gastric and pancreatic adenocarcinoma, but its usefulness in patients with extrahepatic cholangiocarcinoma is unclear. The aim of this study was to evaluate the predictive value of peritoneal cytology in patients with potentially resectable hilar cholangiocarcinoma. This study evaluated a possible association between positive peritoneal cytology and percutaneous transhepatic biliary drainage, which is commonly used in these patients and may result in peritoneal biliary leakage and peritoneal seeding. STUDY DESIGN: From October 1997 through June 2000 26 patients with hilar cholangiocarcinoma underwent staging laparoscopy immediately before planned open exploration and resection. Peritoneal washings were obtained during laparoscopic examination before any biopsies were taken. Cytologic analysis was performed using the Papanicolau technique. RESULTS: There were 18 men and 8 women, with a median age of 69 years (range 42 to 81 years). The most common presenting symptom was jaundice (n = 19). Previous biliary drainage was performed in 23 patients: 9 percutaneous and 14 endoscopic. Metastatic disease was suspected preoperatively in six patients, three to the liver, two to the peritoneum, and one to regional lymph nodes, all of which were confirmed at laparoscopy. Laparoscopy identified five additional patients with metastatic disease. Peritoneal cytology was positive for malignant cells in two patients, both of whom had gross peritoneal metastases. Nine other patients had metastatic disease to distant sites within the abdomen, but none had positive cytology. Overall, six patients had metastatic disease to the peritoneal cavity, only one of whom had undergone earlier percutaneous biliary drainage. CONCLUSIONS: Peritoneal cytology was not predictive of occult metastatic disease. Laparoscopic staging identified some patients with unresectable hilar cholangiocarcinoma, but analysis of peritoneal cytology provided no additional information. There was no association between percutaneous transhepatic biliary drainage and peritoneal tumor seeding.

Adult↗
PubMed2001

Positron emission tomography imaging for herpes virus infection: Implications for oncolytic viral treatments of cancer.

Molecular therapy using viruses would benefit greatly from a non-invasive modality for assessing dissemination of viruses. Here we investigated whether positron emission tomography (PET) scanning using [(124)I]-5-iodo-2'-fluoro-1-beta-d-arabinofuranosyl-uracil (FIAU) could image cells infected with herpes simplex viruses (HSV). Using replication-competent HSV-1 oncolytic viruses with thymidine kinase (TK) under control of different promoters, we demonstrate that viral infection, proliferation and promoter characteristics all interact to influence FIAU accumulation and imaging. In vivo, as few as 1 x 107 viral particles injected into a 0.5-cm human colorectal tumor can be detected by [(124)I]FIAU PET imaging. PET signal intensity is significantly greater at 48 hours compared with that at 8 hours after viral injection, demonstrating that PET scanning can detect changes in TK activity resulting from local viral proliferation. We also show the ability of FIAU-PET scanning to detect differences in viral infectivity at 0.5 log increments. Non-invasive imaging might be useful in assessing biologically relevant distribution of virus in therapies using replication-competent HSV.

Antiviral Agents↗
PubMed2001

Management of 155 patients with benign liver tumours.

BACKGROUND: Benign hepatic tumours continue to represent a diagnostic and therapeutic challenge. This study evaluates the indications and results of resection compared with observation in patients with benign hepatic tumours. METHODS: Patients with a primary diagnosis of benign liver tumour were identified from a prospective database and evaluated retrospectively. RESULTS: From January 1992 to June 1999, 155 patients with benign hepatic tumours were evaluated. The diagnoses included haemangioma (n = 97), focal nodular hyperplasia (FNH) (n = 42), hepatic adenoma (n = 12) and cystadenoma (n = 4). Sixty-eight patients (44 per cent) underwent resection because of symptoms (n = 36), inability to exclude a malignancy (n = 31) or enlargement on serial imaging (n = 11). The operative morbidity and mortality rates were 21 per cent and zero respectively. Thirty patients had a preoperative percutaneous needle biopsy, 19 of which were either incorrect or indeterminate. Overall, 39 of 42 patients with symptoms attributed to the tumour were asymptomatic after resection and 18 of 21 patients with symptoms considered unrelated to the tumour were asymptomatic after a period of observation and/or treatment of unrelated conditions (median follow-up 16 months). CONCLUSION: When indicated, resection of benign liver tumours can be performed safely. Symptomatic patients with a small FNH or haemangioma can be observed because their symptoms are unlikely to be related to the liver tumour. Percutaneous needle biopsy rarely changes management.

Adult↗
PubMed2001

Relevance of Ki-67 antigen expression and K-ras mutation in colorectal liver metastases.

AIMS: The liver is a frequent site of metastases from colorectal cancer. While these lesions are potentially amenable to surgical resection, they are usually very aggressive, and recurrence is frequent. Mutations of the proto-oncogene K- ras are thought to impart a strong growth signal to tumour cells and are closely associated with the development of malignancies of the colon and rectum. Hepatic metastases from colorectal cancer have notably elevated proliferative rates. The present study was performed to investigate the relationship between proliferation or K- ras mutation and prognosis following curative resection of colorectal liver metastases. METHODS: Colorectal liver metastases from 41 patients undergoing curative hepatic resection were examined for proliferation status and presence of K- ras mutations. The proliferative activity was assessed by Ki-67 immunohistochemistry. DNA from the same tissue samples was screened for point mutations in codon 12 of the K- ras gene using a novel microplate-based allelic-specific hybridization assay. Ki-67 scores and K- ras status were then related with patient survival as determined through retrospective analysis. RESULTS: Median survival was 40 months. Patients with high Ki-67 scores (> or = 50%) had significantly shorter median survival compared with those with low scores (30 vs 44 months, log-rank P=0.02). A high Ki-67 score was an independent negative prognostic factor by multivariate regression analysis (relative risk=3.04, P=0.036). K- ras point mutations were detected in 6/41 patients (15%), but mutational status did not correlate with Ki-67 score or survival. CONCLUSIONS: These findings suggest that the tumour proliferative index is a useful predictor of aggressive tumour behaviour and an indicator of patient survival. The presence of K- ras mutations does not appear to correlate with tumour proliferation status or patient survival.

Adult↗
PubMed2001

Specific organ gene transfer in vivo by regional organ perfusion with herpes viral amplicon vectors: implications for local gene therapy.

BACKGROUND: Many gene therapy strategies would benefit from efficient, regional organ delivery of therapeutic genes. METHODS: Regional perfusions of lung, liver, or bladder were performed to determine if rapid and efficient gene transfer can be accomplished in vivo, and to determine if in vivo gene transfer can be limited to the organ of interest. In addition, herpes simplex virus tumor necrosis factor (HSVtnf), carrying the human tumor necrosis factoralpha gene was used as a treatment for methylcholanthrene sarcoma in a syngeneic lung metastases model in Fisher rats. RESULTS: A 20-minute perfusion using HSV carrying beta-galactosidase (HSVlac) produced significant expression of this marker gene isolated to the target organs, without organ-specific tissue injury or inflammation. Regional perfusion of organs with HSV carrying the cytokine gene tumor necrosis factor alpha also resulted in high-level local organ production of this cytokine (2851 +/- 53 pg/g tissue in perfused lung versus 0 for the contralateral lung). For the current vector construct, expression of the gene of interest peaked between 2 and 4 days and was undetectable by 2 weeks after perfusion. In animals undergoing perfusion as treatment for pulmonary sarcoma, there was no difference between tumor counts in lungs perfused with HSVlac (17 +/- 6) or HSVtnf (22 +/- 8), but either treatment resulted in lower tumor counts than controls (111 +/- 24 nodules per lung, P <.02). CONCLUSIONS: Regional organ perfusion using herpes viral vectors is an effective and well-tolerated in vivo method of transiently delivering potentially toxic gene products to target organs in directing gene therapy. Regional lung perfusion with HSV amplicons reduces tumor burden in a rat model of pulmonary metastases, though HSVtnf cannot be demonstrated to augment the cytopathic effect of the HSV amplicon alone in the current model.

Animals↗
PubMed2001

Interleukin 12 secretion enhances antitumor efficacy of oncolytic herpes simplex viral therapy for colorectal cancer.

OBJECTIVE: To assess the strategy of combining oncolytic herpes simplex virus (HSV) therapy with immunomodulatory therapy as treatment for experimental colon cancer. The oncolytic HSV recombinant NV1023 and the interleukin 12 (IL-12)-secreting oncolytic NV1042 virus were evaluated in vitro and in vivo with respect to antitumor efficacy. SUMMARY BACKGROUND DATA: Genetically engineered, replication-conditional, attenuated HSVs have shown oncolytic activity against a wide variety of solid malignancies. Other strategies for treating cancer have involved immunomodulation and cytokine gene transfer using viral vectors. This study has combined both of these strategies by inserting the murine IL-12 gene into a replication-competent HSV. This approach allows oncolytic therapy to replicate selectively within and lyse tumor cells while providing the host immune system with the cytokine stimulus necessary to recruit and activate inflammatory cells needed to enhance the antitumor effect. METHODS: NV1023 is a multimutant HSV based on the wild-type HSV-1 F strain. NV1042 was created by insertion of the mIL-12 gene into NV1023. Cytotoxicity and viral proliferation of both NV1023 and NV1042 within murine CT26 colorectal cancer cells were first shown. Cells infected with NV1042 were then shown to produce significant levels of IL-12. Using an experimental flank model of colon cancer, mice were treated with both high and low doses of NV1023 or NV1042 and were followed up for both cure and reduction in tumor burden. RESULTS: Both viruses could replicate within and kill CT26 cells in vitro, with 100% cytotoxicity achieved after infection by either virus. Only NV1042 could produce mIL-12. Therapy using high viral doses to treat animals in vivo showed equal efficacy between NV1023 and NV1042, with five of seven cures for each virus. When viral doses were lowered, only the cytokine-producing NV1042 virus could reduce tumor burden and cure animals of their disease. CONCLUSIONS: Both NV1023 and NV1042 have the oncolytic potential to kill colon cancer cells at higher doses. Cytokine production by NV1042 may allow lower doses of viral therapy to be used without losing antitumor efficacy. The combination of oncolytic viral therapy and immunomodulatory strategies should be further investigated as treatment for colon cancer.

Animals↗
PubMed2001

Staging, resectability, and outcome in 225 patients with hilar cholangiocarcinoma.

OBJECTIVE: To analyze resectability and survival in patients with hilar cholangiocarcinoma according to a proposed preoperative staging scheme that fully integrates local, tumor-related factors. SUMMARY BACKGROUND DATA: In patients with hilar cholangiocarcinoma, long-term survival depends critically on complete tumor resection. The current staging systems ignore factors related to local tumor extent, preclude accurate preoperative disease assessment, and correlate poorly with resectability and survival. METHODS: Demographics, results of imaging studies, surgical findings, pathology, and survival were analyzed prospectively in consecutive patients. Using data from imaging studies, all patients were placed into one of three stages based on the extent of ductal involvement by tumor, the presence or absence of portal vein compromise, and the presence or absence of hepatic lobar atrophy. RESULTS: From March 1991 through December 2000, 225 patients were evaluated, 77% of whom were seen and treated within the last 6 years. Sixty-five patients had unresectable disease; 160 patients underwent exploration with curative intent. Eighty patients underwent resection: 62 (78%) had a concomitant hepatic resection and 62 (78%) had an R0 resection (negative histologic margins). Negative histologic margins, concomitant partial hepatectomy, and well-differentiated tumor histology were associated with improved outcome after all resections. However, in patients who underwent an R0 resection, concomitant partial hepatectomy was the only independent predictor of long-term survival. Of the 9 actual 5-year survivors (of 30 at risk), all had a concomitant hepatic resection and none had tumor-involved margins; 3 of these 9 patients remained free of disease at a median follow-up of 88 months. The rates of complications and death after resection were 64% and 10%, respectively. In the 219 patients whose disease could be staged, the proposed system predicted resectability and the likelihood of an R0 resection and correlated with metastatic disease and survival. CONCLUSION: By taking full account of local tumor extent, the proposed staging system for hilar cholangiocarcinoma accurately predicts resectability, the likelihood of metastatic disease, and survival. Complete resection remains the only therapy that offers the possibility of long-term survival, and hepatic resection is a critical component of the surgical approach.

Adult↗
PubMed2001

Results of hepatic resection for sarcoma metastatic to liver.

OBJECTIVE: To evaluate the outcome of patients with liver metastases from sarcoma who underwent hepatic resection at a single institution and were followed up prospectively. SUMMARY BACKGROUND DATA: The value of hepatic resection for metastatic sarcoma is unknown. METHODS: There were 331 patients with liver metastases from sarcoma who were admitted to Memorial Hospital from 1982 to 2000, and 56 of them underwent resection of all gross hepatic disease. Patient, tumor, and treatment variables were analyzed to assess outcome. RESULTS: Of the 56 patients who underwent complete resection, 34 (61%) had gastrointestinal stromal tumors or gastrointestinal leiomyosarcomas. Half of the patients required an hepatic lobectomy or extended lobectomy. There were no perioperative deaths in the completely resected group, although 3 of the 75 patients who underwent exploration (4%) died. The postoperative 1-, 3-, and 5-year actuarial survival rates were 88%, 50%, and 30%, respectively, with a median of 39 months. In contrast, the 5-year survival rate of patients who did not undergo complete resection was 4%. On multivariate analysis, a time interval from the primary tumor to the development of liver metastasis greater than 2 years was a significant predictor of survival after hepatectomy. CONCLUSIONS: Complete resection of liver metastases from sarcoma in selected patients is associated with prolonged survival. Hepatectomy should be considered when complete gross resection is possible, especially when the time to the development of liver metastasis exceeds 2 years.

Adult↗
PubMed2001

Functional interaction between fluorodeoxyuridine-induced cellular alterations and replication of a ribonucleotide reductase-negative herpes simplex virus.

G207 is an oncolytic herpes simplex virus (HSV) which is attenuated by inactivation of viral ribonucleotide reductase (RR) and deletion of both gamma(1)34.5 genes. The cellular counterparts that can functionally substitute for viral RR and the carboxyl-terminal domain of ICP34.5 are cellular RR and the corresponding homologous domain of the growth arrest and DNA damage protein 34 (GADD34), respectively. Because the thymidylate synthetase (TS) inhibitor fluorodeoxyuridine (FUdR) can alter expression of cellular RR and GADD34, we examined the effect of FUdR on G207 bioactivity with the hypothesis that FUdR-induced cellular changes will alter viral proliferation and cytotoxicity. Replication of wild-type HSV-1 was impaired in the presence of 10 nM FUdR, whereas G207 demonstrated increased replication under the same conditions. Combined use of FUdR and G207 resulted in synergistic cytotoxicity. FUdR exposure caused elevation of RR activity at 10 and 100 nM, whereas GADD34 was induced only at 100 nM. The effect of enhanced viral replication by FUdR was suppressed by hydroxyurea, a known inhibitor of RR. These results demonstrate that the growth advantage of G207 in FUdR-treated cells is primarily based on an RR-dependent mechanism. Although our findings show that TS inhibition impairs viral replication, the FUdR-induced RR elevation may overcome this disadvantage, resulting in enhanced replication of G207. These data provide the cellular basis for the combined use of RR-negative HSV mutants and TS inhibitors in the treatment of cancer.

Animals↗
PubMed2001

Combination vascular delivery of herpes simplex oncolytic viruses and amplicon mediated cytokine gene transfer is effective therapy for experimental liver cancer.

BACKGROUND: Herpes simplex type I (HSV)-based vectors have been used experimentally for suicide gene therapy, immunomodulatory gene delivery, and direct oncolytic therapy. The current study utilizes the novel concept of regional delivery of an oncolytic virus in combination with or serving as the helper virus for packaging herpes-based amplicon vectors carrying a cytokine transgene, with the goal of identifying if this combination is more efficacious than either modality alone. MATERIALS AND METHODS: A replication competent oncolytic HSV (G207) and a replication incompetent HSV amplicon carrying the gene for the immunomodulatory cytokine IL-2 (HSV-IL2) were tested in murine syngeneic colorectal carcinoma and in rat hepatocellular carcinoma models. Liver tumors were treated with vascular delivery of (1) phosphate-buffered saline (PBS), (2) G207, (3) HSV-IL2, (4) G207 and HSV-IL2 mixed in combination (mG207/HSV- IL2), and (5) G207 as the helper virus for packaging the construct HSV-IL2 (pG207/HSV-IL2). RESULTS: Tumor burden was significantly reduced in all treatment groups in both rats and mice treated with high-dose G207, HSV-IL2, or both (p < 0.02). When a low dose of virus was used in mice, anti-tumor efficacy was improved by use of G207 and HSV-IL2 in combination or with HSV-IL2 packaged by G207 (p < 0.001). This improvement was abolished when CD4(+) and CD8(+) lymphocytes were depleted, implying that the enhanced anti-tumor response to low-dose combined therapy is immune mediated. CONCLUSIONS: Vascular regional delivery of oncolytic and amplicon HSV vectors can be used to induce improved anti-tumor efficacy by combining oncolytic and immunostimulatory strategies.

Animals↗
PubMed2000

Effects of preexisting immunity on the response to herpes simplex-based oncolytic viral therapy.

Herpes simplex viruses (HSV) type 1 are the basis of a number of anticancer strategies that have proven efficacious in animal models. They are natural human pathogens and the majority of adults have anti-HSV immunity. The current study examined the effect of preexisting immunity on the response to herpes-based oncolytic viral treatment of hepatic metastatic cancer in a murine model designed to simulate a clinical approach likely to be utilized for nonneurological tumors. Specifically, the anticancer effects of NV1020 or G207, two multimutated HSV-1 oncolytic viruses, were tested in immunocompetent mice previously immunized with a wild-type herpes simplex type 1 virus. Mice were documented to have humoral as well as cell-mediated immunity to HSV-1. Tumor response to oncolytic therapy was not measurably abrogated by immunity to HSV at the doses tested. The influence of route of viral administration was also tested in models of regional hepatic arterial and intravenous therapy. Route of viral administration influenced efficacy, as virus delivered intravenously produced some detectable attenuation while hepatic arterial therapy remained unaffected. These results demonstrate that when given at appropriate doses and in reasonable proximity to tumor targets, HSV-based oncolytic therapy can still be expected to be effective treatment for patients with hepatic malignancies.

Animals↗