Naohiro Nomura

A phase I dose-escalation clinical trial of intraoperative direct intratumoral injection of HF10 oncolytic virus in non-resectable patients with advanced pancreatic cancer

In 2005, we initiated a clinical trial that examined the efficacy of the oncolytic virus HF10 to treat pancreatic cancer. Pancreatic cancer continues to have a high mortality rate, despite multimodal treatments for patients, and new therapeutic methods are greatly needed. The current mainstream methods for cancer treatment include biological therapeutics such as trastuzumab (Herceptin) for breast cancer or erlotinib (Tarceva) for non-small cell lung cancer. Oncolytic virus therapy is a new and promising treatment strategy for cancer. Oncolytic viruses are novel biological therapeutics for advanced cancer that appear to have a wide spectrum of anticancer activity with minimal human toxicity. To examine the efficacy of oncolytic virus therapy for pancreatic cancer, we initiated pilot studies by injecting six patients with non-resectable pancreatic cancer with three doses of HF10. All patients were monitored for 30 days for local and systemic adverse effects and were not administered any other therapeutics during this period. There were no adverse side-effects, and we observed some therapeutic potential based on tumor marker levels, survival, pathological findings and diagnostic radiography. The tumors were classified as stable disease in three patients, partial response in one patient and progressive disease in two patients.

Effects of tumor selective replication-competent herpes viruses in combination with gemcitabine on pancreatic cancer

PurposePancreatic cancer still has a poor prognosis, even if aggressive therapy is pursued. Currently, new modalities of oncolytic virus therapy are being tested against this cancer. The combination of one of two representative mutant herpes simplex viruses (R3616: γ134.5 inactivated, hrR3: UL39 inactivated) with a standard anti-pancreatic cancer chemotherapy drug (gemcitabine), was investigated in this study.Experimental designThe intracellular concentration of ribonucleotide reductase was estimated by Western blotting. The effect of gemcitabine on viral replication and the total cytotoxic effect of the combination therapy were investigated on pancreatic cancer cell lines. We compared the results of two oncolytic viruses, R3616 and hrR3. A mouse model of pancreatic cancer with peritoneal dissemination was used to evaluate the in vivo effect of the combination therapy.ResultsAlthough the replication of both viruses was inhibited by gemcitabine, the combination caused more tumor cell cytotoxicity than did virus alone in vitro. The results with R3616 were more striking. Although the difference was not statistically significant, R3616 with gemcitabine had a greater effect than did R3616 alone, while hrR3 with gemcitabine had a weaker effect than did hrR3 alone in vivo experiments.ConclusionThe combination of oncolytic virus with gemcitabine is a promising new strategy against advanced pancreatic cancer. Each virus has different functional characteristics, and can affect the results of the combination of viruses and chemotherapy drugs. The results indicate that there is a complicated interaction among viruses, cells, and chemotherapy drugs and that the best combination of oncolytic virus and chemotherapeutic agents should be studied more extensively before embarking on a clinical trial.

Nonfunctioning neuroendocrine pancreatic tumors: our experience and management

BACKGROUND AND PURPOSE We present our experience in the treatment of nonfunctioning neuroendocrine pancreatic tumors (NFNPTs) to define the clinical and pathological characteristics and to suggest proper management. METHODS The records of 17 patients with NFNPTs operated on between 1998 and 2008 were retrospectively reviewed, and all tumors were classified clinicopathologically as benign, uncertain, and malignant, based on the World Health Organization (WHO) classification of neuroendocrine tumors. RESULTS There were four benign, six uncertain, and seven malignant NFNPTs. The most frequent symptoms were abdominal pain (five patients) and obstructive jaundice (one patient). Most of these symptomatic patients had malignant tumors. Mean tumor size of benign, uncertain, and malignant tumors were 1.0 +/- 0.3, 3.2 +/- 1.6, and 5.3 +/- 2.4 cm, respectively. Metastatic lesions of malignant tumors were lymph node (six patients), liver (four patients), and adrenal gland (one patient). Six of seven patients with malignant tumors underwent curative rejection. There were recurrences in four of six patients with curatively rejected malignant tumors. Two patients underwent more rejection, three patients received systemic chemotherapy, and two patients underwent radiofrequency ablation and transcatheter arterial chemoembolization for liver metastases. Survival of patients with malignant tumors was significantly shorter than that of patients with benign and uncertain tumors. However, three patients with malignant tumors had long survival of more than 3 years, even with metastases or recurrences. CONCLUSIONS Aggressive surgical resection should be performed in patients with resectable NFNPTs, even with metastases. Even when a tumor was unresectable or there were recurrences, long-time palliation could be achieved by a multidisciplinary approach.

Suitability of a US3-inactivated HSV mutant (L1BR1) as an oncolytic virus for pancreatic cancer therapy.

Recently, the use of oncolytic viruses against cancer has attracted considerable attention. We studied the potential of the US3 locus-deficient herpes simplex virus (HSV), L1BR1, for oncolytic virus therapy. Its high specificity and potency indicate that L1BR1 is a promising candidate as a new oncolytic virus against pancreatic cancer. Moreover, the virus exhibited the unique characteristic of increasing apoptosis when used in combination with anticancer drugs. We assessed the feasibility of using the US3 locus-deficient HSV named L1BR1 as a new replication-competent oncolytic virus for the treatment of pancreatic cancer. The US3 locus of HSV has been shown to be a key gene in producing a multifunctional protein kinase that inhibits apoptosis induced by viral infections, chemicals and ultraviolet (UV) light. L1BR1 has been reported to be more than 10 000-fold less virulent than the parental virus in mice. In this study, we examined the tumor specificity and oncolytic effect of this attenuated replication-competent virus, L1BR1, in pancreatic cancers derived from SW1990, Capan2 and Bxpc-3cells compared with the parent virus and other well-known oncolytic herpes viruses (R3616 and hrR3). We also studied the efficacy of L1BR1 for the induction of apoptosis as an attribute of this virus in combination with the anticancer drugs 5FU and cisplatin. The combined treatment of the pancreatic cancer cells with L1BR1 and these anticancer drugs enhanced apoptosis significantly. More importantly, L1BR1 showed the lowest replication capacity in normal human hepatocytes, but the highest tumor-reducing effect in vivo among the oncolytic herpes viruses tested. In addition, L1BR1 significantly increased the induction of apoptosis of cancer cells when treated in combination with anticancer drugs although the parental virus inhibited the induction of apoptosis. These results suggest that L1BR1 is promising as a new anticancer oncolytic virus.

Impact of novel oncolytic virus HF10 on cellular components of the tumor microenviroment in patients with recurrent breast cancer

Oncolytic viruses are a promising method of cancer therapy, even for advanced malignancies. HF10, a spontaneously mutated herpes simplex type 1, is a potent oncolytic agent. The interaction of oncolytic herpes viruses with the tumor microenvironment has not been well characterized. We injected HF10 into tumors of patients with recurrent breast carcinoma, and sought to determine its effects on the tumor microenvironment. Six patients with recurrent breast cancer were recruited to the study. Tumors were divided into two groups: saline-injected (control) and HF10-injected (treatment). We investigated several parameters including neovascularization (CD31) and tumor lymphocyte infiltration (CD8, CD4), determined by immunohistochemistry, and apoptosis, determined by terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Median apoptotic cell count was lower in the treatment group (P=0.016). Angiogenesis was significantly higher in treatment group (P=0.032). Count of CD8-positive lymphocytes infiltrating the tumors was higher in the treatment group (P=0.008). We were unable to determine CD4-positive lymphocyte infiltration. An effective oncolytic viral agent must replicate efficiently in tumor cells, leading to higher viral counts, in order to aid viral penetration. HF10 seems to meet this criterion; furthermore, it induces potent antitumor immunity. The increase in angiogenesis may be due to either viral replication or the inflammatory response.

Oncolytic virus therapy--foreword.

We are very pleased and proud to be able to publish this special issue of Current Cancer Drug Targets devoted to oncolytic virus therapy covering basic and clinical research on adenovirus, vaccinia virus, herpes virus, and Newcastle disease virus. In these papers, we welcome the worlds top authorities in the field who have generously contributed their latest review articles for exclusive publication in this special issue. Moreover, this issue also includes a range of opinion from government drug organizations. Here we simply wish to bring together the newest knowledge and experience in the field of cutting-edge oncolytic virus therapy for researchers and every kind of cancer therapist. The Foreword presents a historical perspective on the development of oncolytic virus together with the encouraging results of recent clinical trials (e.g., H101 has been tested in clinical trial of nearly 250 patients and approved for human use by the Chinese FDA, while PV701 has been tried in over 110 patients, as described in our special issue).

High Therapeutic Potential for Systemic Delivery of a Liposomeconjugated Herpes Simplex Virus

PURPOSE Oncolytic viral therapy is a newly developed modality to treat tumors. Many clinical trials worldwide have examined the efficacy of locally injected oncolytic viruses. However, systemic intravascular injections are limited by the humoral immune response, which dramatically decreases the level of infection. To overcome this limitation, we encapsulated the oncolytic virus in liposomes. METHODS The infectious properties of the herpes simplex virus type 1 (HSV-1) mutant, hrR3, with or without liposomes in the presence of neutralizing antibodies were evaluated using replication and cytotoxicity assays in vitro. To evaluate the efficacy of intravascular virus therapy with liposomes in the presence of neutralizing antibodies, immunized mice bearing multiple liver metastases were intraportally or peritoneally administered hrR3 or hrR3 complexed with liposomes. RESULTS Anti-HSV antibodies attenuated the infectiousness and cytotoxicity of hrR3, whereas hrR3/liposome complexes were not attenuated by these anti-HSV antibodies. Although the survival rate of non-immunized mice treated with hrR3 alone was similar to that of mice treated with the hrR3/liposome complexes, the survival rates of immunized mice treated with hrR3 alone were significantly reduced compared to mice treated with the hrR3/liposome complexes. CONCLUSIONS This systemic intravascular delivery of hrR3/liposome complexes in the presence of pre-existing neutralizing antibodies is effective to treat multiple liver metastases.

Considerations for intravascular administration of oncolytic herpes virus for the treatment of multiple liver metastases

PurposeOncolytic viral therapy is a newly developed modality for treating tumors. Many clinical trials using oncolytic virus have been performed worldwide, but most of them have used local injection in the tumor. Determination of the effect and safety of intravascular virus injection instead of local injection is necessary for clinical use against multiple liver metastases and systemic metastases.MethodsTo evaluate the efficacy and safety of intravascular virus therapy, mice bearing multiple liver metastases were treated by intraportal or intravenous administration of the herpes simplex virus type 1 (HSV-1) mutant, hrR3. Mice treated with hrR3 were killed and organs were harvested for lacZ staining and PCR analysis. Inactivation of oncolytic virus in bloodstream was assessed by neutralization assay in vitro. Infectious activity of hrR3 with vascular endothelial cells was evaluated by replication and cytotoxicity assay.ResultsThe survival rate of animals treated by hrR3 was significantly improved compared with the untreated group. lacZ staining and PCR analysis demonstrated detectable virus in the tumor but not in normal tissue or other organs except for the adrenal glands. We also showed that vascular endothelial cells allowed virus replication, while normal hepatocytes did not, and human anti-HSV antibody revealed attenuation of the infectious activity of hrR3.ConclusionsIntravascular delivery of hrR3 is effective in treating multiple liver metastases, however, several points must be kept in mind at the time of human clinical trials using intravascular virus administration in order to avoid critical side effects.

Efficient sampling strategies for forecasting pharmacokinetic parameters of irinotecan (CPT-11): implication for area under the concentration-time curve monitoring.

A linear two-compartment Bayesian pharmacokinetic model was developed using a standard two-stage population method for the novel anti-cancer agent CPT-11 from 11 adult patients with refractory cancer. The accuracy and efficiency of this Bayesian model for estimating pharmacokinetic parameters including the area under the concentration-time curve (AUC) was then evaluated using two different sampling strategies in a new study cohort of 13 patients with cancer. Sampling strategies included either one, two, or three nonsteady-state feedback levels determined empirically and from optimal sampling theory (D-optimality). All 24 patients in this study received CPT-11 (60 mg/m2) as a 90-min infusion. Pharmacokinetic parameters derived from the Bayesian model combined with these limited sampling strategies were compared with those parameters obtained from the full sample data sets (n = 10) analyzed by weighted nonlinear least squares regression (reference method). The least-bias and most precise sampling times for estimating AUC were 3.5; 3.5 and 9.5; and 0.5, 3.5, and 9.5 h, respectively. At these times, only marginal improvement in precision of the AUC estimate was observed using two versus three samples. However, the precision of the estimate of clearance was not improved using two versus three samples. The sampling times derived from optimal sampling theory were 0.25, 3.5, 8.5, and 24 h and correlated closely to the actual and best empirical sampling times of 0.5, 3.5, 9.5, and 24 h. These results strongly suggest that Bayesian estimation combined with only two optimally timed samples accurately predicts the AUC of CPT-11 and should be useful for implementing adaptive control dosing for monitoring CPT-11 systemic exposure in patients with cancer.

Antitumor efficacy of oncolytic herpes simplex virus adsorbed onto antigen-specific lymphocytes

Although several studies have reported that locally administering oncolytic viruses effectively targets malignancies, the efficacy of systemically administered oncolytic viruses is restricted. Recently, however, it was reported that systemic administration of oncolytic vesicular stomatitis virus adsorbed onto antigen-specific lymphocytes was effective against malignancies. We hypothesized that intravenously administering such virus might have significant potential in treatment of the malignant tumors. We adsorbed oncolytic herpes simplex virus-1 mutant R3616 onto lymphocytes harvested from mice with acquired antitumor immunity. We administered adsorbed R3616 to peritoneally disseminated tumors and analyzed the efficacy of this treatment. Mice administered adsorbed R3616 survived significantly longer than mice administered R3616 adsorbed onto non-specific lymphocytes, or mice administered either virus or tumor antigen-specific lymphocytes alone. In this context, herpes oncolytic virus is a promising treatment not only for primary lesions, but also for multiple metastasizing lesions. This treatment strategy may become one of the most effective methods for systemic virus delivery.