Hepatocellular carcinoma (HCC) is an orphan disease in the United States with an estimated incidence of 28,720 cases and prevalence of 35,557 cases in 2012. Most patients with HCC cannot undergo potentially curative treatments such as surgery or transplantation. In patients with advanced disease and for those in whom loco-regional therapy is no longer feasible, sorafenib is the only available FDA approved therapy. No known effective therapies are available to patients resistant/intolerant to sorafenib, and as such there is a clear unmet medical need. This proposal involves the conduct of a first-in-human study of vesicular stomatitis virus with human interferon beta gene insert (VSV-hIFN-B) in patients with advanced hepatocellular carcinoma (HCC) who are refractory/intolerant to sorafenib based therapies. The innovative aspects of the proposal are to utilize a recombinant oncolytic vector that has multiple favorable characteristics. These include: 1)low prevalence of human infection in the general population to wild type vesicular stomatitis virus (VSV), 2)rapid replication kinetics, 3)inability of VSV to integrate into host genome, 4)broad tropism for mammalian cells, 5)differential sensitivity of tumor cells to VSV due to preponderance of defective type I interferon pathways in tumors and 6) multifaceted mechanism of action including CD4+/CD8+, NK cell mediated anti-tumor activity and direct cytolysis. Insertion of the human interferon beta (hIFN-B) allows for attenuation of the wild type vector and subsequent reduction of risk of neurotoxicity while maintaining anti-tumor efficacy. An added feature to the transgene insert is the potential for CD4+/CD8+ mediated anti-tumor efficacy. Preclinical studies conducted with VSV-hIFN-B by our group and by others with wild type VSV and other VSV constructs, have demonstrated potent anti-tumor activity in both in vitro and in vivo HCC models. This encouraging preclinical data formed the basis for our group to conduct formal GLP toxicology studies in rats and Rhesus macaques. A starting dose for first-in-human studies was established in this context (105 TCID50 [Tissue Culture Infective Dose 50]). The current proposal entails the conduct of a first-in-human study of VSV-hIFN-B delivered as single as well as multiple intra-tumoral injections in sorafenib refractory/intolerant patients with advanced HCC. A "3+3" dose escalation schema will be utilized with 0.6log increments. Objectives for the study include : 1) Determination of the maximum tolerated dose (MTD), dose limiting toxicities (DLTs), recommended phase II dose (RP2D) and observation for evidence of antitumor activity, 2) Assessment of the pharmacokinetic (PK), pharmacodynamic (PD) and biodistribution (BD) properties of the agent will be performed. PK will be assessed by measuring VSV-hIFN-B in PBMCs and tumor serially by RT-qPCR. PD assessments are hIFN-B and VSV antibody detection. BD will entail assessment of VSV-hIFN-B in blood, saliva, feces and urine by RT-qPCR and infectious virus recovery with Vero cell assay. and 3) From a translational perspective, immunological assessments entail measuring T cell response, both CD4+ and CD8+ and also innate immune response mediated by NK cells. Given the differential between normal and tumor tissue with regards to ability to mount type I interferon response, we will also measure the transcriptional dynamics of VSV-hIFN-B using serial assessment of whole transcriptome sequencing (RNASeq). Conduct and completion of this study will allow for further studies investigating alternate routes of delivery (intravenous and trans-arterial infusion) and combination with existing therapies such as trans-arterial chemoembolization (TACE) and immunotherapeutics such as anti-CTLA4/anti-PD1 antibodies.

Public Health Relevance

Hepatocellular cancer (HCC) is an orphan disease in the United States with less than 29,000 new cases and 36,000 total cases per year. Sorafenib is the only FDA approved therapy for patients who have advanced HCC. Unfortunately, a majority of patients eventually develop resistance to, or cannot tolerate sorafenib due to side effects. No known effective therapies are available for these patients. This application proposes the conduct of an initial clinical study of a novel virotherapy, vesicular stomatitis virus with human interferon beta gene insert (VSV-hIFN-B) in patients with HCC that are resistant to or cannot tolerate sorafenib. Emphasis will be placed on determining the highest safe dose, dose for future studies, severe side effects and distribution of the virus in bodily fluids such as feces, urine, blood and saliva. We will also study the effects of VSV-hIFN-B on activation of the immune system and the changes that occur in genes that are part of the interferon pathway whose normal function is to suppress viral infections. Finally, we will assess for any preliminary evidence (such as tumor shrinkage) that VSV-hIFN-B has activity against HCC. This initial clinical study will allow for further development of this novel therapy for patients with HCC for whom a paucity of effective therapies are currently available.

National Institute of Health (NIH)
Food and Drug Administration (FDA)
Research Project (R01)
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Special Emphasis Panel (ZFD1-OPD-N (S1))
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Mayo Clinic, Arizona
United States
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