Recent clinical trials have begun to evaluate the safety and tolerability of new therapies that use viruses that can infect and kill human cancer cells.
A new treatment called Vaxinia can reduce the size of a wide range of cancers in animal and laboratory models at low doses.
This new treatment holds great promise due to its ability to selectively target cancer cells and target a wide range of advanced cancers.
In a recent Phase 1 clinical trial, early study participants received an experimental cancer drug called CF33-hNIS or Vaxinia. This new treatment involves the use of an oncolytic virus, a type of virus that can infect and kill cancer cells without damaging healthy tissue.
A genetically modified variola virus, poxvirus, has previously been shown to be effective against a wide range of cancers in laboratory and animal models. A clinical trial, in collaboration with Australian biotechnology company Imugene, will be conducted by City of Hope, a US-based cancer research and treatment facility, to test new oncolytic viruses in cancer patients with advanced solid tumors.
According to laboratory studies, Vaxinia may be more effective in reducing tumor size than previous generation oncolytic viruses, and this treatment is especially promising.
Dr. Yuman Fong, director of surgery for the City of Hope, told Medical News Today: “The special significance of CF33/Vaxinia is that this virus is designed to fight all types of cancer. It is much more powerful than previous viruses and more selective for cancer. This is one of the first therapeutic viruses of a new generation that can and can preserve normal tissue.”
Leslie Chong, CEO of Imugene, told MNT: Turning cancer into one disease and having a targeted drug to kill it is the holy grail of cancer treatment! “
Oncolytic viruses include naturally occurring or genetically modified viruses that selectively infect and replicate tumor cells.
When the oncolytic virus replicates, it can destroy and kill infected tumor cells. When a tumor cell ruptures, it releases a tumor protein or antigen that the immune system recognizes as a foreign body. An immune response is then elicited against these antigens, leading to further death of the tumor cells.
In addition, the ability of the immune system to recognize tumor cells helps build a memory of tumor antigens and prevent cancer recurrence. In addition to providing strong protection, small amounts of oncolytic viruses can be effective against tumors because the virus is able to replicate and spread within tumor cells.
Cancer cells express different proteins and receptors on their surface than healthy cells that help evade the immune system, metastasize, and prevent cell death. Oncolytic viruses use these cancer-specific proteins and receptors to target them.
Dr. Fong said: “Interestingly, the same properties that ultimately make cancer cells resistant to chemotherapy and radiation therapy actually contribute to the success of oncolytic viruses such as CF33-hNIS.”
In addition, the proteins targeted by oncolytic viruses are often common to a wide variety of cancers, making these viruses a versatile tool.
Target tumor cells with Vaxinia
CF33-hNIS or Vaxinia, developed by City of Hope researchers, is a genetically engineered version of the vaccinia or smallpox virus. The researchers developed CF33-hNIS to increase the ability to replicate in tumor cells and stimulate a strong immune response against tumor cells.
In addition, the modified vaccinia virus also expresses a protein called the human sodium iodide symporter (hNIS), which transports iodide ions into the cell. Therefore, virus-infected tumor cells can express hNIS and take up radioactive iodine.
Imaging techniques such as positron emission tomography (PET) can then be used in combination with radioactively labeled iodine as a dye to help monitor the spread of the virus in the body and its effectiveness.
In addition, hNIS helps to selectively target tumor cells that accumulate radioactive iodine during radiation therapy.