Fluorescence-guided assessment of bone and soft-tissue sarcomas for predicting the efficacy of telomerase-specific oncolytic adenovirus.

Bone and soft-tissue sarcomas are rare malignancies with histological diversity and tumor heterogeneity, leading to the lack of a common molecular target. Telomerase is a key enzyme for keeping the telomere length and human telomerase reverse transcriptase (hTERT) expression is often activated in most human cancers, including bone and soft-tissue sarcomas. For targeting of telomerase-positive tumor cells, we developed OBP-301, a telomerase-specific replication-competent oncolytic adenovirus, in which the hTERT promoter regulates adenoviral E1 gene for tumor-specific viral replication. In this study, we present the diagnostic potential of green fluorescent protein (GFP)-expressing oncolytic adenovirus OBP-401 for assessing virotherapy sensitivity using bone and soft-tissue sarcomas. OBP-401-mediated GFP expression was significantly associated with the therapeutic efficacy of OBP-401 in human bone and soft-tissue sarcomas. In the tumor specimens from 68 patients, malignant and intermediate tumors demonstrated significantly higher expression levels of coxsackie and adenovirus receptor (CAR) and hTERT than benign tumors. OBP-401-mediated GFP expression was significantly increased in malignant and intermediate tumors with high expression levels of CAR and hTERT between 24 and 48 h after infection. Our results suggest that the OBP-401-based GFP expression system is a useful tool for predicting the therapeutic efficacy of oncolytic virotherapy on bone and soft-tissue sarcomas.

The efficacy and safety assessment of oncolytic virotherapies in the treatment of advanced melanoma: a systematic review and meta-analysis.

BACKGROUND: The efficacy and safety of oncolytic virotherapies in the treatment of advanced melanoma still remains controversal. It is necessary to conduct quantitative evaluation on the basis of preclinical trial reports. METHODS: Publicly available databases (PubMed, Embase, Medline, Web of Science and Cochrane Library.) and register (Clinicaltrials.gov) were searched to collect treatment outcomes of oncolytic virotherapies (including herpes simplex virus type 1 (HSV), coxsackievirus A21 (CVA21), adenovirus, poxvirus and reovirus) for advanced/unresectable melanoma. Comparisons of treatment response, adverse events (AEs) and survival analyses for different virotherapies were performed by R software based on the extracted data from eligible studies. RESULTS: Finally, thirty-four eligible studies were analysed and HSV virotherapy had the highest average complete response (CR, 24.8%) and HSV had a slightly higher average overall response rate (ORR) than CVA21 (43.8% vs 42.6%). In the pooled results of comparing talimogene laherparepve (T-VEC) with or without GM-CSF/ICIs (immune checkpoint inhibitors) to GM-CSF/ICIs monotherapy suggested virotherapy was more efficient in subgroups CR (RR = 1.80, 95% CI [1.30; 2.51], P < 0.01), ORR (RR = 1.17, 95% CI [1.02; 1.34], P < 0.05), and DCR (RR = 1.27, 95% CI [1.15; 1.40], P < 0.01). In patients treated with T-VEC+ICIs, 2-year overall survival (12.1 ± 6.9 months) and progression-free survival (9.9 ± 6.9) were significantly longer than those treated with T-VEC alone. Furthermore, we found that AEs occurred frequently in virotherapy but decreased in a large cohort of enrolled patients, some of which, such as abdominal distension/pain, injection site pain and pruritus, were found to be positively associated with disease progression in patients treated with T-VEC monotherapy. CONCLUSION: Given the relative safety and tolerability of oncolytic viruses, and the lack of reports of dose-limiting-dependent toxicities, more patients treated with T-VEC with or without ICIs should be added to future assessment analyses. There is still a long way to go before it can be used as a first-line therapy for patients with advanced or unresectable melanoma.

Preclinical safety assessment of an oncolytic herpes simplex virus type 2 expressed PD-L1/CD3 bispecific antibody.

Oncolytic virotherapy is an emerging and safe therapeutic approach based on the inherent cytotoxicity of oncolytic viruses and their ability to replicate and spread within tumors in a selective manner. We constructed a new type of oncolytic herpes simplex virus armed with Bispecific Antibody (BsAb) molecules targeting PD-L1/CD3 (oHSV2-PD-L1/CD3-BsAb) to treat human malignancies. We demonstrated the anti-tumor efficacy of oHSV2-PD-L1/CD3-BsAb. To move forward with clinical trials of oHSV2-PD-L1/CD3-BsAb, we conducted a comprehensive preclinical safety evaluation, including hemolysis test, anaphylaxis test, repeated dose toxicity test in cynomolgus monkeys, biodistribution in cynomolgus monkeys and tissue cross-reactivity of PD-L1/CD3-BsAb with human and cynomolgus monkey tissues in vitro. Our preclinical safety evaluation indicated that oHSV2-PD-L1/CD3-BsAb is safe and suitable for clinical trials. After undergoing a thorough evaluation by the United States Food and Drug Administration (FDA), oHSV2-PD-L1/CD3-BsAb has successfully obtained approval to initiate Phase I clinical trials in the United States (FDA IND: 28717).

Assessment of Clinical Response to V937 Oncolytic Virus After Intravenous or Intratumoral Administration Using Physiologically-Based Modeling.

Oncolytic viruses (OVs) represent a potential therapeutic strategy in cancer treatment. However, there is currently a lack of comprehensive quantitative models characterizing clinical OV kinetics and distribution to the tumor. In this work, we present a mechanistic modeling framework for V937 OV, after intratumoral (i.t.) or intravascular (i.v.) administration in patients with cancer. A minimal physiologically-based pharmacokinetic model was built to characterize biodistribution of OVs in humans. Viral dynamics was incorporated at the i.t. cellular level and linked to tumor response, enabling the characterization of a direct OV killing triggered by the death of infected tumor cells and an indirect killing induced by the immune response. The model provided an adequate description of changes in V937 mRNA levels and tumor size obtained from phase I/II clinical trials after V937 administration. The model showed prominent role of viral clearance from systemic circulation and infectivity in addition to known tumor aggressiveness on clinical response. After i.v. administration, i.t. exposure of V937 was predicted to be several orders of magnitude lower compared with i.t. administration. These differences could be overcome if there is high virus infectivity and/or replication. Unfortunately, the latter process could not be identified at the current clinical setting. This work provides insights on selecting optimal OV considering replication rate and infectivity.

Preclinical safety assessment of toxicity and biodistribution of oncolytic virus HSV-1 expressing human PD-1 antibody in mice.

HSV-1/hPD-1 is composed of engineered herpes simplex virus type-1 and two inserted copies of the human PD-1 antibody sequence. It is a novel oncolytic virus product designed to cure malignancies. The objective of this study was to estimate its toxicity in mice. In the single-dose toxicity study, no mortality and abnormal symptoms were observed in animals injected with 4.0 × 107 pfu/mouse dose. In the repeat-dose toxicity study, HSV-1/hPD-1 in animals intramuscularly treated with 1.0 × 107, 2.0 × 107, or 4.0 × 107 pfu/mouse doses was well tolerated in terms of clinical observation, body weight, food consumption, hematology and biochemistry indexes, T lymphocyte counting, immune reaction, and organ weight, except for some histopathological changes, such as the irreversible degeneration of the sciatic nerve, which was considered related to the adopted administration route. Synchronously, a biodistribution study in mice was performed to examine whether HSV-1/hPD-1 could spread to the injection site, gonads, liver, lung, heart, mesenteric and inguinal lymph nodes, skin, dorsal root ganglia, and blood, and then be gradually eliminated. Thus, two safety dose levels-the maximum tolerance dose of 4.0 × 107 pfu/mouse and the no-observed-adverse-effect-level dose of 1.0 × 107 pfu/mouse-were determined to help design patients' dose regimens. Our research data have been successfully accepted for investigational new drug (IND) application in China.

Opportunities and challenges for applying model-informed drug development approaches to gene therapies.

As part of the US Food and Drug Administration (FDA)'s Prescription Drug User Fee Act (PDUFA) VI commitments, the Center for Biologics Evaluation and Research (CBER) and Center for Drug Evaluation and Research (CDER) are conducting a model-informed drug development (MIDD) pilot program. Sponsor(s) who apply and are selected will be granted meetings that aim to facilitate the application of MIDD approaches throughout the product development lifecycle and the regulatory process. Due to their complex mechanisms of action and limited clinical experience, cell and gene therapies have the potential to benefit from the application of MIDD methods, which may facilitate their safety and efficacy evaluations. Leveraging data that are generated from all stages of drug development into appropriate modeling and simulation techniques that inform decisions remains challenging. Additional discussions regarding the application of quantitative modeling approaches to drug development decisions, such as through the MIDD pilot program, may be crucial for both the sponsor(s) and regulatory review teams. Here, we share some perspectives on the opportunities and challenges for utilizing MIDD approaches for product review, which we hope will encourage investigators to publish their experiences and application of MIDD in gene therapy product development.

Assessment of replication of bovine herpesvirus type 4 in human glioblastoma and breast cancer cells as a potential oncolytic virus.

Oncolytic viruses have been extensively used in cancer treatment due to their tropism, selective replication only in tumor cells, and possible synergic interaction with other therapeutics. Different researchers have demonstrated that bovine herpesvirus 4 (BoHV-4), a member of the gammaherpesviridae family, has oncolytic potential in some human-origin cancer cell lines like glioma through the selective replication strategy. Using four apoptosis detection methods, namely MTT, LDH, TUNEL, and Annexin V assays, we evaluated the apoptotic effect of BoHV-4 Movar33/63 reference strain along with a recombinant BoHV-4 expressing EGFP in U87 MG cells (human glioblastoma cell line), MDA MB-231 (human breast cancer cell line), and MCF10a (non-tumorigenic human mammary epithelial cell line). Our findings indicate that this virus can replicate and induce apoptosis in these cell lines and hinder in vitro proliferation in a dose-dependent manner. In conclusion, BoHV-4 has in vitro potential as a novel oncolytic virus in human cancer therapy. However, its replication potential in the MCF10a cells as a non-tumorigenic human mammary epithelial cell line is a concern in using this virus in cancer therapy, at least against human mammary tumors. Further studies must therefore be conducted to examine the specific apoptotic pathways induced by this virus to move on to further experiments.

A Cellular Automata Model of Oncolytic Virotherapy in Pancreatic Cancer.

Oncolytic virotherapy is known as a new treatment to employ less virulent viruses to specifically target and damage cancer cells. This work presents a cellular automata model of oncolytic virotherapy with an application to pancreatic cancer. The fundamental biomedical processes (like cell proliferation, mutation, apoptosis) are modeled by the use of probabilistic principles. The migration of injected viruses (as therapy) is modeled by diffusion through the tissue. The resulting diffusion-reaction equation with smoothed point viral sources is discretized by the finite difference method and integrated by the IMEX approach. Furthermore, Monte Carlo simulations are done to quantitatively evaluate the correlations between various input parameters and numerical results. As we expected, our model is able to simulate the pancreatic cancer growth at early stages, which is calibrated with experimental results. In addition, the model can be used to predict and evaluate the therapeutic effect of oncolytic virotherapy.

Assessment of efficacy of dendritic cell therapy and viral therapy in high grade glioma clinical trials. A meta-analytic review.

In recent years, immunotherapy has raised the interest of many studies and provided different perspectives for the therapeutic management of high grade glioma. Our meta-analysis focused on the effectiveness of dendritic cell (DC) therapy and viral therapy (VT) in clinical trials. Fourteen eligible studies have been evaluated and the results suggest the improvement of both OS (HR = 0.65) (p < 0.0001) and PFS (HR = 0.59) (p = 0.01) for patients receiving DC therapy. The data for VT showed a slight improvement in terms of OS (HR = 0.81), while PFS was similar to the control arms (HR = 1.06) (p = 0.41).

Quantitative Assessment of the Health Risk for Livestock When Animal Viruses Are Applied in Human Oncolytic Therapy: A Case Study for Seneca Valley Virus.

Some viruses cause tumor regression and can be used to treat cancer patients; these viruses are called oncolytic viruses. To assess whether oncolytic viruses from animal origin excreted by patients pose a health risk for livestock, a quantitative risk assessment (QRA) was performed to estimate the risk for the Dutch pig industry after environmental release of Seneca Valley virus (SVV). The QRA assumed SVV excretion in stool by one cancer patient on Day 1 in the Netherlands, discharge of SVV with treated wastewater into the river Meuse, downstream intake of river water for drinking water production, and consumption of this drinking water by pigs. Dose-response curves for SVV infection and clinical disease in pigs were constructed from experimental data. In the worst scenario (four log10 virus reduction by drinking water treatment and a farm with 10,000 pigs), the infection risk is less than 1% with 95% certainty. The risk of clinical disease is almost seven orders of magnitude lower. Risks may increase proportionally with the numbers of treated patients and days of virus excretion. These data indicate that application of wild-type oncolytic animal viruses may infect susceptible livestock. A QRA regarding the use of oncolytic animal virus is, therefore, highly recommended. For this, data on excretion by patients, and dose-response parameters for infection and clinical disease in livestock, should be studied.

A Comparative Safety Profile Assessment of Oncolytic Virus Therapy Based on Clinical Trials.

Oncolytic virus therapy (OVT) represents a new class of therapeutic agents in cancer treatment. The molecular and cellular mechanisms of action of OVTs have been evaluated in nonclinical/clinical phase trials. Various genetically modified viruses have been developed as oncolytic agents, and the first approval of an OVT for clinical use was issued by the US Food and Drug Administration in 2015. In this context, more and more clinical development of OVTs is anticipated in the future. This article provides a risk assessment of OVT based on the safety data obtained from all clinical trials to date using a publicly available database. The most common adverse events (AEs) observed in clinical trials have been infection-related symptoms such as fatigue, chills, fever, and nausea; few serious AEs have been observed, regardless of the kind of virus or transfected genes. In vivo systemic infusion of OVTs demonstrated a high percentage of AEs, but most AEs were manageable using common drugs. This paper describes OVTs' specific safety/toxicity profiles and encourages the performance of further clinical trials of OVTs to address the most serious challenges anticipated in the development of OVTs as a new class of drugs for the treatment of cancer.

[Great advances in the systemic treatment in malignant melanoma patients]. / Stora framsteg för systemisk behandling vid malignt melanom.

Great advances in the systemic treatment in malignant melanoma patients Up until a few years ago there was no systemic treatment with the capacity to  prolong overall survival for patients with advanced malignant melanoma. Several new treatments have been established in clinical practice in recent years and they belong to two main groups; checkpoint inhibitors and inhibitors of an intracellular pathway (MAP kinase). The latter drugs are only active in melanomas with an activating BRAF mutation, which is present in half of the patients. Side effect management is important and in particular for the checkpoint inhibitors, which activate the immune system and frequently provoke immune related reactions. The introduction of these new treatments has substantially improved prognosis and some patients might even be cured. Based on ongoing research, more therapeutic breakthroughs can be anticipated in the years to come.

Talimogene Laherparepvec for Treating Metastatic Melanoma: An Evidence Review Group Perspective of a NICE Single Technology Appraisal.

The National Institute for Health and Care Excellence (NICE) invited the manufacturer (Amgen) of talimogene laherparepvec (T-VEC) to submit clinical and cost-effectiveness evidence for previously untreated advanced (unresectable or metastatic) melanoma as part of the Institute's Single Technology Appraisal process. The Liverpool Reviews and Implementation Group (LRiG) at the University of Liverpool was commissioned to act as the Evidence Review Group (ERG). This article presents a summary of the company's submission of T-VEC, the ERG review and the resulting NICE guidance (TA410), issued in September 2016. T-VEC is an oncolytic virus therapy granted a marketing authorisation by the European Commission for the treatment of adults with unresectable melanoma that is regionally or distantly metastatic (stage IIIB, IIIC and IVM1a) with no bone, brain, lung or other visceral disease. Clinical evidence for T-VEC versus granulocyte-macrophage colony-stimulating factor (GM-CSF) was derived from the multinational, open-label randomised controlled OPTiM trial [Oncovex (GM-CSF) Pivotal Trial in Melanoma]. In accordance with T-VEC's marketing authorisation, the company's submission focused primarily on 249 patients with stage IIIB to stage IV/M1a disease who constituted 57% of the overall trial population (T-VEC, n = 163 and GM-CSF, n = 86). Results from analyses of durable response rate, objective response rate, time to treatment failure and overall survival all showed marked and statistically significant improvements for patients treated with T-VEC compared with those treated with GM-CSF. However, GM-CSF is not used to treat melanoma in clinical practice. It was not possible to compare treatment with T-VEC with an appropriate comparator using conventionally accepted methods due to the absence of comparative head-to-head data or trials with sufficient common comparators. Therefore, the company compared T-VEC with ipilimumab using what it described as modified Korn and two-step Korn methods. Results from these analyses suggested that treatment with T-VEC was at least as effective as treatment with ipilimumab. Using the discounted patient access scheme (PAS) price for T-VEC and list price for ipilimumab, the company reported incremental cost-effectiveness ratios (ICERs) per quality-adjusted life-year (QALY) gained. For the comparison of treatment with T-VEC versus ipilimumab, the ICER per QALY gained was -£16,367 using the modified Korn method and -£60,271 using the two-step Korn method. The NICE Appraisal Committee (AC) agreed with the ERG that the company's methods for estimating clinical effectiveness of T-VEC versus ipilimumab were flawed and therefore produced unreliable results for modelling progression in stage IIIB to stage IVM1a melanoma. The AC concluded that the clinical and cost effectiveness of treatment with T-VEC compared with ipilimumab is unknown in patients with stage IIIB to stage IV/M1a disease. However, the AC considered that T-VEC may be a reasonable option for treating patients who are unsuitable for treatment with systemically administered immunotherapies (such as ipilimumab). T-VEC was therefore recommended by NICE as a treatment option for adults with unresectable, regionally or distantly metastatic (stage IIIB to stage IVM1a) melanoma that has not spread to bone, brain, lung or other internal organs, only if treatment with systemically administered immunotherapies is not suitable and the company provides T-VEC at the agreed discounted PAS price.