Researchers have created an immunotherapy technique against melanoma that can also be used as a vaccine. The technique uses a melanin-containing lysate of melanoma cells that is applied as a patch. The research was done by scientists at North Carolina University and the paper was published last week in Science Immunology.
The technique starts with a lysate made from a tumor puree consisting of ruptured melanoma cells. This lysate is used to fill an array of microneedles that are embedded in a polymeric transdermal patch. When the lysate is applied to the skin, it triggers an immune response.
Because the melanoma consists of melanin pigment, it is able to absorb light. Shining IR light onto the transdermal patch causes the light to be absorbed and the temperature of the skin to rise where the patch is applied, causing a fever-like environment that promotes release of the lysate. This also causes an increase in blood and lymphatic flow. Combined, these effects boost the ability of the immune system to remember and respond to the contents of the lysate.
The researchers tested the patch’s effects in three groups of mice. Two groups got the patch, but one was exposed to IR light and the other was not. A third control group received an empty patch. Ten days after the patch was applied, they were injected with melanoma.
Within one month, all of the mice in the control group had died. Only 13% of those that received the patch and no light survived, while 100% of the mice who received the patch and IR light had survived after two months- 87% of this group had no tumors.
Next, the patch was tested on mice who had already developed two tumors, one on each side of their body. The patch was placed on the left tumor. Mice that received the patch plus light saw a significant reduction in tumor size for both tumors. The patch without light was only moderately effective, limiting tumor growth (particularly on the left), but not shrinking the tumors.
A third experiment in which lysate from two others cancers was used showed similar results.
These results suggest that this technique might be useful for targeting cancer metastasis and primary tumors, but further studies are needed to confirm the results. The researchers note that the next steps will be to do a larger animal study that further evaluates the safety and efficacy of the new technique.