JX-594 is an oncolytic virus is designed to target and destroy cancer cells. [1] It is also known as Pexa-Vec, [2] INN pexastimogene devacirepvec [3] ) and was constructed in Dr. Edmund Lattime's lab at Thomas Jefferson University, tested in clinical trials on melanoma patients, and licensed and further developed by SillaJen.
JX-594 is a modified Copenhagen [4] strain (or Wyeth strain [3] ) vaccinia poxvirus engineered by addition of the GM-CSF gene and deletion of the thymidine kinase gene which limits viral replication to cells with high levels of thymidine kinase, typically seen in cancer cells with a mutated RAS or p53 gene. [5] The virus also has the LacZ gene insertion under control of the p7.5 promoter. [3] The virus kills the infected/cancer cells by lysis and also expresses GM-CSF which may help initiate an anti-tumour immune response. [6] [7] [8]
It has orphan drug designation from US Food and Drug Administration and EUMA[ clarification needed ] for the treatment of hepatocellular carcinoma (liver cancer). [2]
In clinical trials doses have been administered by intratumoral or intravenous injection. [3]
Pexa-Vec (JX-594) is the most advanced product candidate from SillaJen's proprietary SOLVE™ (Selective Oncolytic Vaccinia Engineering) platform. [9] [ non-primary source needed ] SOLVE [9] is used to optimize virus targeting to specific cancer types, to select transgenes to include into the viral genome, and to optimize viral infection and/or replication selectively through targeted mutations.
Oncolytic viruses could have 3-prolonged attack on cancer: direct cell lysis with replication and spread, immune activation, and antivascular [10] [11] [12] [13]
JX-900 (VVDD): [15] VVDD Platform: Next-gen enhanced oncolytic immunotherapy. [16]
A phase 3 randomized, open-label, clinical trial of Pexa-Vec plus sorafenib versus sorafenib is being conducted on patients with advanced hepatocellular carcinoma who have not previously received any systemic therapy. The study is being done to determine and compare overall survival for patients in the two treatment arms. [17] [ non-primary source needed ] The study is Sponsored by SillaJen, Inc. [18]
The experimental therapy, Pexa-Vec, is an attenuated vaccinia virus engineered to stimulate anti-tumor immunity and directly lyse tumor cells. Pexa-Vec has cancer selectivity through the deactivation of its thymidine kinase gene, and it has been engineered to express the granulocyte-macrophage colony-stimulating factor gene to stimulate a systemic anti-tumor immune response. Researchers believe that Pexa-Vec may be a systemic treatment of hepatocellular carcinoma by inducing tumor necrosis and shrinkage of both injected and non-injected tumors after direct intratumoral delivery. Final data from a randomized dose-ranging phase 2 study of Pexa-Vec [19] in mainly sorafenib naïve patients with advanced hepatocellular carcinoma demonstrated that the risk of death for patients who received Pexa-Vec at the high dose was markedly reduced (by nearly 60 percent; hazard ratio = 0.41) when compared to patients randomized to a low dose control (one-tenth of the high dose). The median overall survival for high and low dose groups was 14.1 months versus 6.7 months, respectively (p = 0.020 for superiority of the high dose). Pexa-Vec was well tolerated, with patients experiencing transient flu-like symptoms that generally resolved within 24 hours. [17]
As of June 2018, [update] these are the clinical trials investigating Pexa-Vec. [20] [21] [22] [23] [ needs update ]
Indication | Phase | Status | Notes | Sponsor | Ref |
---|---|---|---|---|---|
Hepatocellular carcinoma | III | Recruiting | Combined with sorafenib | SillaJen | NCT02562755 |
Solid Tumors | II | Recruiting | Combined with metronomic cyclophosphamide | Investigator | NCT02630368 |
Renal Cell Carcinoma 2L | I | Recruiting | Combined with REGN2810 | SillaJen | NCT03294083 |
Colorectal Cancer 2L/3L | I | Recruiting | Combined with PD-L1 and CTLA4 | Investigator | |
Liver Cancer | I | Recruiting | Combined with Nivolumab | Transgene | NCT03071094 |
Solid Tumors | I | Recruiting | Combined with Ipilimumab | Investigator | NCT02977156 |
Participants will be randomly assigned to one of two treatment arms, having an equal chance of receiving either Pexa-Vec followed by sorafenib, or sorafenib alone.[ citation needed ]
Novel oncolytic viruses in SillaJen pipeline are engineered through the Selective Oncolytic Vaccinia Engineering (SOLVE) platform. [24]
JX-929 is derived from Western Reserve strain vaccinia virus. JX-929's tumor selectivity has been optimized through deletion of thymidine kinase and vaccinia growth factor. JX-929 has been administered as a monotherapy to patients with breast, colorectal, and pancreatic cancer via intratumoral & intravenous injections in a Phase 1, dose escalation clinical trial. This Phase 1 study showed delivery to and replication within tumors [25] both IT [26] and IV. [27] [ clarification needed ]
JX-970 is also derived from a Western Reserve strain vaccinia virus and utilizes the same tumor selectivity mechanisms as JX-929. In addition, it expresses granulocyte-macrophage colony-stimulating factor to stimulate immune responses. In nonclinical studies, the JX-970 backbone exerted a tumor debulking effect and at the same time demonstrated a selective preference for tumor tissues. [26] The precursor of JX-970 is JX-963 which demonstrated efficacy in pre-clinical studies.[ citation needed ]
Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer in adults and is currently the most common cause of death in people with cirrhosis. HCC is the third leading cause of cancer-related deaths worldwide.
Cancer immunotherapy (immuno-oncotherapy) is the stimulation of the immune system to treat cancer, improving the immune system's natural ability to fight the disease. It is an application of the fundamental research of cancer immunology (immuno-oncology) and a growing subspecialty of oncology.
An oncolytic virus is a virus that preferentially infects and kills cancer cells. As the infected cancer cells are destroyed by oncolysis, they release new infectious virus particles or virions to help destroy the remaining tumour. Oncolytic viruses are thought not only to cause direct destruction of the tumour cells, but also to stimulate host anti-tumour immune system responses. Oncolytic viruses also have the ability to affect the tumor micro-environment in multiple ways.
Virotherapy is a treatment using biotechnology to convert viruses into therapeutic agents by reprogramming viruses to treat diseases. There are three main branches of virotherapy: anti-cancer oncolytic viruses, viral vectors for gene therapy and viral immunotherapy. These branches use three different types of treatment methods: gene overexpression, gene knockout, and suicide gene delivery. Gene overexpression adds genetic sequences that compensate for low to zero levels of needed gene expression. Gene knockout uses RNA methods to silence or reduce expression of disease-causing genes. Suicide gene delivery introduces genetic sequences that induce an apoptotic response in cells, usually to kill cancerous growths. In a slightly different context, virotherapy can also refer more broadly to the use of viruses to treat certain medical conditions by killing pathogens.
Sorafenib, sold under the brand name Nexavar, is a kinase inhibitor drug approved for the treatment of primary kidney cancer, advanced primary liver cancer, FLT3-ITD positive AML and radioactive iodine resistant advanced thyroid carcinoma.
Selective internal radiation therapy (SIRT), also known as transarterial radioembolization (TARE), radioembolization or intra-arterial microbrachytherapy is a form of radionuclide therapy used in interventional radiology to treat cancer. It is generally for selected patients with surgically unresectable cancers, especially hepatocellular carcinoma or metastasis to the liver. The treatment involves injecting tiny microspheres of radioactive material into the arteries that supply the tumor, where the spheres lodge in the small vessels of the tumor. Because this treatment combines radiotherapy with embolization, it is also called radioembolization. The chemotherapeutic analogue is called chemoembolization, of which transcatheter arterial chemoembolization (TACE) is the usual form.
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Brivanib alaninate (INN/USAN) also known as BMS-582664 is an investigational, anti-tumorigenic drug for oral administration. The drug is being developed by Bristol-Myers Squibb for the treatment of hepatocellular carcinoma or HCC, the most common type of liver cancer. Brivanib is no longer in active development.
Jennerex Biotherapeutics, Inc. was an American private biopharmaceutical company that developed the oncolytic viruses JX-594 and JX-929 among others. By creating oncolytic viruses that can (1) kill tumor cells directly through lysis, (2) activate the immune system by delivering genes that encode immunostimulants and by overcoming tumor cell-induced immunological tolerance, and (3) reduce tumor nutrient supply through the destruction of blood vessels, Jennerex aimed to create a novel approach to treating and possibly curing cancer.
Talimogene laherparepvec, sold under the brand name Imlygic among others, is a biopharmaceutical medication used to treat melanoma that cannot be operated on; it is injected directly into a subset of lesions which generates a systemic immune response against the recipient's cancer. The final four year analysis from the pivotal phase 3 study upon which TVEC was approved by the FDA showed a 31.5% response rate with a 16.9% complete response (CR) rate. There was also a substantial and statistically significant survival benefit in patients with earlier metastatic disease and in patients who hadn't received prior systemic treatment for melanoma. The earlier stage group had a reduction in the risk of death of approximately 50% with one in four patients appearing to have met, or be close to be reaching, the medical definition of cure. Real world use of talimogene laherparepvec have shown response rates of up to 88.5% with CR rates of up to 61.5%.
Many variants of herpes simplex virus have been considered for viral therapy of cancer; the early development of these was thoroughly reviewed in the journal Cancer Gene Therapy in 2002. This page describes the most notable variants—those tested in clinical trials: G207, HSV1716, NV1020 and Talimogene laherparepvec. These attenuated versions are constructed by deleting viral genes required for infecting or replicating inside normal cells but not cancer cells, such as ICP34.5, ICP6/UL39, and ICP47.
Adenovirus varieties have been explored extensively as a viral vector for gene therapy and also as an oncolytic virus.
Atezolizumab, sold under the brand name Tecentriq among others, is a monoclonal antibody medication used to treat urothelial carcinoma, non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC), hepatocellular carcinoma and alveolar soft part sarcoma, but discontinued for use in triple-negative breast cancer (TNBC). It is a fully humanized, engineered monoclonal antibody of IgG1 isotype against the protein programmed cell death-ligand 1 (PD-L1).
GL-ONC1 is an investigational therapeutic product consisting of the clinical grade formulation of the laboratory strain GLV-1h68, an oncolytic virus developed by Genelux Corporation. GL-ONC1 is currently under evaluation in Phase I/II human clinical trials in the United States and Europe.
Genelux Corporation is a publicly traded late clinical-stage company developing a pipeline of next-generation oncolytic viral immunotherapies for patients suffering from aggressive and/or difficult-to-treat solid tumor types. The Company’s most advanced product candidate, Olvi-Vec, is a proprietary, modified strain of the vaccinia virus (VACV), a stable DNA virus with a large engineering capacity.
Enadenotucirev is an investigational oncolytic virus that is in clinical trials for various cancers.
Adeno-associated virus (AAV) has been researched as a viral vector in gene therapy for cancer treatment as an oncolytic virus. Currently there are not any FDA approved AAV cancer treatments, as the first FDA approved AAV treatment was approved December 2017. However, there are many Oncolytic AAV applications that are in development and have been researched.
SillaJen, Inc. is a South Korea-based biotechnology company, with offices in Busan, Yangsan and Seoul, South Korea, and San Francisco, California.
Transgene S.A. is a French biotechnology company founded in 1979. It is based in Illkirch-Graffenstaden, near Strasbourg, and develops and manufactures immunotherapies for the treatment of cancer.
Cytokines are polypeptides or glycoproteins that help immune cells communicate to each other to induce proliferation, activation, differentiation, and inflammatory or anti-inflammatory signals in various cell types. Studies utilizing cytokines for antitumor therapies has increased significantly since 2000, and different cytokines provide unique antitumor activities. Cytokines hinder tumor cell development mostly through antiproliferative or proapoptotic pathways but can also interrupt development indirectly by eliciting immune cells to have cytotoxic effects against tumor cells. Even though there are FDA-approved cytokine therapies, there are two main challenges associated with cytokine delivery. The first is that cytokines have a short half-life, so frequent administration of high doses is required for therapeutic effect. The second is that systemic toxicity could occur if the cytokines delivered cause an intense immune response, known as a cytokine storm.
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