The Emerging Role of Oncolytic Virus Therapy in Fighting Cancer

The notion of using viruses in cancer therapy is not new. But in the last 15 years, we have begun to understand that the actual value of viruses for cancer therapies lies within immunotherapy.

One of these immunotherapies is the oncolytic virus (OV) and its emerging as an exciting field of study that focuses on developing viruses that specifically target and destroy cancer cells while leaving healthy cells unharmed.

Biotech companies are working hard to refine this approach to use the natural ability of viruses to infect cells and replicate within them to selectively kill cancer cells. Oncolytic viruses are designed to exploit the differences between normal cells and cancer cells, as cancer cells often have alterations in their signaling pathways, DNA repair mechanisms, and cell cycle control, which make them more susceptible to viral infection.

When an oncolytic virus infects a cancer cell, it replicates within the cell and causes it to burst, releasing new virus particles that can then infect nearby cancer cells. As this process repeats, the virus can spread throughout the tumor, infecting, and killing more and more cancer cells. In addition, the process of viral replication and lysis can stimulate an immune response that can help to further attack and kill cancer cells.

https://www.futuremedicine.com/doi/10.2217/fon-2022-0440

Oncolytic virus research is important for several reasons:

• A new approach to cancer therapy: Oncolytic viruses offer a new and innovative approach to cancer therapy that has the potential to complement or replace traditional chemotherapy, radiation therapy, and surgery.
• Directly target cancer cells: Oncolytic viruses are specifically designed to target and destroy cancer cells while leaving healthy cells intact. This targeted approach can reduce the side effects associated with traditional cancer therapies.
• Stimulate the immune system: Oncolytic viruses can stimulate the immune system to recognize and attack cancer cells, potentially providing a more long-lasting response to therapy.
• Enhance other cancer therapies: Oncolytic viruses can enhance the efficacy of other cancer therapies, such as chemotherapy and radiation therapy, potentially making these treatments more effective and reducing the dose required.
• Potential for personalized medicine: Oncolytic viruses can be designed to specifically target certain types of cancer, providing the potential for personalized medicine and tailored treatment approaches for individual patients.

Several different oncolytic viruses are being studied as potential cancer therapies, including adenovirus, herpes simplex virus, and measles virus, among others. Some oncolytic viruses have been shown to be effective against a variety of different types of cancer, including melanoma, prostate cancer, and ovarian cancer.

Nearly 80 OV programs have made it into human testing, with four reaching approval, though only one in the United States (Amgen’s T-VEC/Imlygic approved by FDA in 2015). T-VEC (Imlygic®) is a modified herpes simplex virus (HSV) that infects tumor cells and promotes their destruction; approved for subsets of patients with melanoma.

Oncolytic virus platforms under evaluation in clinical trials include:

• Adenovirus
• Herpes simplex virus
• Measles
• Newcastle Disease Virus
• Picornavirus
• Reovirus
• Vaccinia virus
• Vesicular stomatitis virus

While there are many exciting developments in OV therapies, a few key players are taking a leading role in this research.

• Amgen: Launched Imlygic, the first and only FDA-approved oncolytic virus therapy in the U.S.
• Oncorus: Developing a differentiated portfolio of RNA-based immunotherapies to transform outcomes for patients with cancer.
• BioEclipse: Hybrid approach involving patient-derived killer cells treated ex-vivo with cytokines and infected with vaccinia virus.
• Oncolytic Biotech: Developing a non-pathogenic double-stranded RNA reovirus therapy known as Pelareorep.
• Vyriad: Has a broad portfolio of oncolytic viruses in discovery, translational and clinical phases of development.
• Tessa Therapeutics: Overcoming the challenges of applying CAR – cells in solid tumors by combining CAR-T cells and binary oncolytic virus therapy.

In part two of this blog, we’ll look at the exciting benefits of oncolytic virus therapy as well as the challenges and barriers to its widespread adoption.