Written By: Devin Golden
Mesothelioma Oncolytic Virus Therapy (Virotherapy)
Mesothelioma oncolytic virus therapy, also called mesothelioma virotherapy, is an innovative cancer treatment that utilizes genetically modified viruses to target and destroy malignant mesothelioma cells. These engineered viruses infect tumor cells, replicate inside them, and ultimately cause the cancer cells to die while releasing tumor antigens that stimulate an immune response. This dual action makes oncolytic viruses an emerging mesothelioma treatment.
Medically Reviewed By
Dr. Stephen Williams
Precision Oncology Scientist
Medically Reviewed By
Dr. Stephen Williams
Precision Oncology Scientist
JUMP TO A TOPIC
Important Facts About Mesothelioma Oncolytic Virus Therapy
- Oncolytic virus therapy is a cutting-edge mesothelioma treatment that uses genetically engineered viruses to selectively infect and destroy mesothelioma cells while sparing healthy tissues.
- Oncolytic viruses also cause dead cancer cells to release hidden antigens, which can activate the immune system.
- Oncolytic viruses are FDA-approved for certain types of cancer but are in testing and development as a treatment for mesothelioma.
- In clinical trials, oncolytic viruses have helped people survive for an average of nearly two years, which is a significant improvement compared to standard treatments alone.
How Does Oncolytic Virus Therapy Work as a Cancer Treatment?
Viruses are microscopic infectious agents made up of genetic material encased in a protein shell. Their natural function is to invade host cells, “hijack” their machinery, and replicate, eventually causing the infected cells to burst and die.
Decades of research have demonstrated that viruses can naturally target and destroy cancer cells. Scientists are harnessing these properties to develop oncolytic virus therapy. This innovative cancer treatment is designed to selectively attack malignant cells while leaving healthy tissue unharmed.
Scientists take natural viruses, such as the herpes simplex virus, and genetically modify them in laboratories. The modifications channel the oncolytic virus to look for specific cancer cells, which also prevents the virus from infecting healthy cells.
Using Oncolytic Virus Therapy for Mesothelioma
Mesothelioma is an aggressive cancer of the mesothelium, which is a thin, protective lining in the body. These linings are made up of mesothelial cells, which can mutate and become cancerous, leading to malignant mesothelioma.
The mesothelial linings include the:
- Pleura, a lining around both lungs (pleural mesothelioma)
- Peritoneum, a lining inside the abdominal cavity (peritoneal mesothelioma)
- Pericardium, a lining around the heart (pericardial mesothelioma)
Unlike some types of cancer that form one solid tumor, mesothelioma spreads as multiple microscopic tumors, making treatment more challenging. It tends to quickly invade nearby organs, requiring advanced therapies to slow or halt its progression.
Most types of mesothelioma treatment, like chemotherapy and radiation, struggle to contain these tumors on their own. Surgery can remove a large amount of tumors at once, but many patients are not good candidates for surgery since the operation is aggressive and may involve removing an organ (such as a lung).
How Oncolytic Virus Therapy Fights Mesothelioma
Oncolytic virus therapy leverages genetically modified viruses to seek out and destroy malignant mesothelioma cells while leaving healthy tissues unharmed. These viruses work by:
- Targeting cancer cells – Scientists engineer viruses to specifically attach mesothelioma cells.
- Infiltrating tumors – The virus is introduced into the tumor, infecting cancerous cells directly.
- Replicating inside the tumor – The virus multiplies within the cancer cells, eventually causing them to burst.
- Preventing tumor spreading – The destruction of mesothelioma cells releases tumor antigens, which alerts the immune system.
- Sparing healthy cells – Oncolytic virus therapy ignores healthy cells due to the modifications and may die after their anti-tumor response, which keeps the engineered viruses safe for patients.
Types of Oncolytic Virus Therapy for Mesothelioma
There are two main types of oncolytic virus therapy for mesothelioma:
- Viral vectors for other therapies – These viruses serve as delivery systems, carrying therapeutic genes or drugs to mesothelioma cells to enhance other treatments like immunotherapy or chemotherapy.
- Viral immunotherapy – These viruses kill cancer cells and stimulate the immune system to attack other cancer cells.
Examples of Oncolytic Virus Therapies for Mesothelioma
- ONCOS-102 – A genetically modified virus with immune-stimulating properties, ONCOS-102 is one of the most advanced oncolytic virus therapies for mesothelioma.
- GL-ONC1 – A modified version of the vaccinia virus (originally used to eradicate smallpox), GL-ONC1 is being tested in clinical trials at Memorial Sloan-Kettering Cancer Center for its ability to fight mesothelioma.
- MV-NIS – A reprogrammed measles virus under investigation at the Mayo Clinic, MV-NIS can target and kill mesothelioma cells.
- Interferon Alpha-2B (TR002) – A viral therapy, TR002 delivers a gene encoding Interferon Alpha-2B, a potent immune-stimulating protein that helps T cells recognize and attack tumors.
- Gold nanotube therapy – This is a unique approach where tiny gold nanotubes enter mesothelioma cells, absorb light, and overheat the cells, leading to their destruction.
Viral Vectors
Oncolytic viruses can serve as a transport for other therapies, particularly gene therapy or immunotherapy for mesothelioma. The viruses act as a cargo train, transporting gene therapy or immunotherapy directly to the area where mesothelioma exists. Once the transport is complete, the virus deactivates.
This approach minimizes damage to healthy cells while enhancing the effectiveness of other cancer treatments.
TR002
One of the most advanced viral vector therapies is TR002, a virus engineered to deliver the Interferon Alpha-2B gene, which triggers a strong response from the immune system against mesothelioma.
- Phase 3 clinical trial – TR002 is currently being tested in a phase 3 trial in the United States to evaluate its effectiveness in mesothelioma treatment.
- Mechanism of action – Once TR002 reaches the tumor site, it releases Interferon Alpha-2B, a powerful immune-boosting protein that helps the body recognize and destroy cancer cells.
- Combination potential – Researchers are investigating whether combining TR002 with chemotherapy or immune checkpoint inhibitors can further improve patient outcomes.
Viral Immunotherapy
Viral immunotherapy harnesses the body’s immune system by using the virus’ presence in the body to stimulate an immune response. The immune system’s T cells are responsible for identifying and destroying harmful invaders – from common infections to cancerous tumors.
How Viral Immunotherapy Works for Mesothelioma
- Virus introduction – A modified virus is inserted directly into the location of mesothelioma tumors.
- Viral infection – The virus infects mesothelioma tumor cells and causes them to burst and die. This releases the fingerprints of the cancer, previously hidden within the cancer cells.
- Immune system activation – The immune system recognizes the virus as foreign, sending T cells in large numbers to the affected area.
- Tumor recognition – The bursting of the cancer cells and release of the fingerprints helps the T cells to recognize the mesothelioma cells as a threat.
- Cancer cell destruction – After identifying the cancer cells as harmful, the immune system sends more T cells to the area to begin systematically attacking the cancer, hopefully stopping the disease from spreading in the body.
Examples of Viral Immunotherapy for Mesothelioma
ONCOS-102 is an engineered virus that infects mesothelioma cells and boosts immune system activity. Read more about ONCOS-102 for mesothelioma.
Benefits of Oncolytic Virus Therapy for Mesothelioma
Oncolytic virus therapy is a fast-rising mesothelioma treatment method for numerous reasons. Most notably, it can improve survival time as a second-line option after other therapies have failed. This therapy has demonstrated potential in improving survival rates, reducing side effects, and offering treatment for late-stage mesothelioma cases.
Fewer Side Effects
Traditional chemotherapy can cause severe nausea, fatigue, and weight loss, making treatment difficult for many patients. Oncolytic virus therapy tends to have milder side effects due to its selective targeting of cancer cells.
Potential Side Effects of Oncolytic Virus Therapy
- Flu-like symptoms (chills, fatigue, fever, nausea)
- Mild immune system response (caused by the presence of the virus in the body)
Since oncolytic viruses are designed to ignore healthy cells, the side effects are typically much less severe than the side effects of mesothelioma chemotherapy.
Option for Late-Stage Patients
Late-stage mesothelioma often offers limited treatment options, as surgery is rarely an effective option when tumors have spread and chemotherapy provides only modest benefits. Oncolytic virus therapy may offer new hope for patients by slowing or even stopping tumor progression, potentially transforming mesothelioma into a manageable chronic illness.
ONCOS-102 for Late-Stage Mesothelioma
- Most patients in ONCOS-102 clinical trials had stage 3 or stage 4 mesothelioma.
- Half of the participants survived at least 21 months.
- The average survival time for stage 3 and stage 4 mesothelioma is 8-14 months.
The Future of Oncolytic Virus Therapy for Mesothelioma
If ongoing trials continue to show strong survival benefits and fewer side effects, oncolytic virus therapy could become a new standard treatment for mesothelioma, particularly for patients who do not qualify for surgery. Research is also exploring oncolytic virus therapy combined with immunotherapy and gene therapy to further enhance its effectiveness.
Frequently Asked Questions About Oncolytic Virus Therapy for Mesothelioma
How does oncolytic virus therapy work for mesothelioma?
Oncolytic virus therapy is an emerging mesothelioma treatment that inserts manipulated viruses into the tumor site to disrupt cancer cells from growing. The oncolytic virus therapy drugs either attack tumors or escalate the immune system’s ability to fight cancer by activating the T cells and other cancer-fighting mechanisms to recognize mesothelioma tumors.
Does oncolytic virus therapy improve survival for mesothelioma patients?
Oncolytic virus therapy is featured in quite a few clinical trials for mesothelioma, but more research is needed before declaring that this mesothelioma treatment consistently improves survival for patients. ONCOS-102, for instance, is an oncolytic virus that kills cancer cells and activates the immune system. In the latest study, requiring further investigation, ONCOS-102 plus chemotherapy improved mesothelioma survival by six months.
What are the types of oncolytic virus therapy?
There are two main types of oncolytic virus therapy for mesothelioma:
- Viral vectors, which transfers a gene therapy or immunotherapy into the tumor site with the intent of activating the immune system or reprogramming cancer cells’ genetics so they die quickly
- Viral immunotherapy, which infects cancer cells while stimulating the immune system so it responds to the cancer (an example of viral immunotherapy is ONCOS-102)
Sources & Author
- Intrapleural Administration of GL-ONC1, a Genetically Modified Vaccinia Virus, in Patients With Malignant Pleural Effusion: Primary, Metastases and Mesothelioma. Clinicaltrials.gov. Retrieved from: https://clinicaltrials.gov/ct2/show/NCT01766739. Accessed: 03/24/2021.
- Efficacy & Safety of rAd-IFN Administered With Celecoxib & Gemcitabine in Patients With Malignant Pleural Mesothelioma. U.S. National Library of Medicine. Retrieved from: https://clinicaltrials.gov/ct2/show/NCT03710876. Accessed: 10/02/19.
- Tiny golden bullets could help tackle asbestos-related cancers. EurekAlert. Retrieved from: https://www.eurekalert.org/pub_releases/2020-10/uoc-tgb102620.php. Accessed: 10/29/2020.
- ONCOS – Oncolytic Virus. Targovax. Retrieved from: https://www.targovax.com/en/oncos-oncolyctic-virus/. Accessed: 01/28/2020.
- Continued survival benefit in Targovax’s ONCOS-102 trial in mesothelioma at the 21-month follow-up. PRNewswire. Retrieved from: https://www.prnewswire.com/news-releases/continued-survival-benefit-in-targovaxs-oncos-102-trial-in-mesothelioma-at-the-21-month-follow-up-301233073.html. Accessed: 02/23/2021.
- Oncolytic Virus Therapy. Cancer Research Institute. Retrieved from: https://www.cancerresearch.org/immunotherapy/treatment-types/oncolytic-virus-therapy. Accessed: 03/24/2021.
- Trizell Ltd. announces Phase 3 pivotal study of interferon alfa-2b gene therapy in malignant pleural mesothelioma. PRNewswire. Retrieved from: https://www.prnewswire.com/news-releases/trizell-ltd-announces-phase-3-pivotal-study-of-interferon-alfa-2b-gene-therapy-in-malignant-pleural-mesothelioma-300815572.html. Accessed: 03/25/2021.
