New Immunotherapy Drug Acts Like a Virus So Your Immune System Will Destroy Tumors
Recent findings published in the journal Science Translational Medicine show that a new drug that mimics the behaviors of a virus can help to target certain hard-to-recognize cancer cells, which tricks the immune system into destroying certain kinds of tumors. This discovery is promising because it leads researchers to believe these kinds of treatments can be used to improve other immunotherapy approaches in the treatment of various cancers.
The drug is called BO-112, and it impersonates the RNA of certain viruses. During an infection, a virus will inject its RNA into the targeted cells. These cells typically recognize this invasion through use of special receptors known as interferons, which stimulate the immune system to spring into action in order to fight the infection.
The problem is that some cancer cells are able to cloak themselves in order to hide from the immune system’s attack. They avoid interferon signaling. BO-112 allows these cells to be detected by marking them as an invader so that the immune system can differentiate them from healthy cells. Once they’re marked for destruction, the immune system can go on to readily detect other similar cells in order to more effectively destroy them.
In response to viral infection, interferons not only stimulate the immune system, they also inhibit the replication of a virus. When BO-112 is injected into a tumor, it works to enhance interferon signaling and slow tumor division. This mechanism can help the immune system better identify and kill tumor cells.
Enhancing existing immunotherapy practices
This drug has been tested on mice and a small human study sample. Study researchers hope their findings can be used to boost existing immunotherapy cancer treatments.
One type of treatment, known as activation immunotherapy, works to boost the body’s own natural immune defense against tumors. There are also therapies geared toward reducing or suppressing the immune system response, called suppression immunotherapies. In addition, scientists can create substances in a lab that are synthetic versions of components of the immune system in order to use them to improve the function of a patient’s own defenses.
Adoptive T cell therapy is one immunotherapy currently being used in the treatment of cancer. In it, a patient’s immune cells are extracted and modified in order to be able to better recognize certain types of tumors. The T cells are then put back in the body and set to work in order to detect antigens on cells and destroy them.
Some tumors inhibit or even stop the production of antigens on their surface, making them impossible to detect by T cells. It’s these mutations that the introduction of BO-112 into tumors is able to correct, allowing antigens to be visible by T cells and destroyed.
In order to test this theory, researchers conducted initial trials on mice. They mutated mouse cells to reduce the number of antigens on their surfaces. T cells were not detected in these lab experiments. The team then activated a gene known as NLRC5 in these tumors. The engineered tumors then began to produce antigens that could be attacked by the immune system. These results were replicated in both lab dishes and in living mice.
However, it is impossible to trigger such a specific gene in humans. That’s where BO-112 comes in. It acts as a virus to trick the cancerous cells into producing antigens. A group of researchers then took the results gained from the mice experiments and conducted a small human trial of 44 patients. Subjects received injections of BO-112 along with their existing immunotherapy drugs: nivolumab and pembrolizumab.
The researchers determined in the trial that tumors were indeed shown to be more sensitive to existing drug treatments with the addition of BO-112 injections. Because the sample size was so small, more studies will need to be performed in order to determine whether the results were significant. However, this seems to be a promising indicator that BO-112 can help to overcome some tumor resistance to immunotherapy, making these therapies more effective in the treatment of certain types of cancer.