The world continues to sense extraordinary excitement at the prospect for fighting cancer after a recent trial at Sloan Kettering Hospital in Manhattan where the immunotherapy drug dostarlimab has essentially cured 14 patients of the disease. Dostarlimab is sold under the brand name Jemperli, and it is expensive. It was approved in Canada in December. As defined, it is a product of the field of cancer immunotherapy — the harnessing of the body’s own immune system to kill cancer. Here is the key to how dostarlimab works as published by Understanding Cancer Immunotherapy Research
Jemperli is an antibody that attaches to a molecule called PD-1, which is present on the surface of T cells. In healthy T cells, PD-1 acts as a brake that prevents the cells from creating an out-of-control immune response. However, in tumors, PD-1 can make T cells inactive and can prevent them from doing their job of killing the cancer cells. This happens because cancer cells or other cells within the tumor have an increased concentration of PD-L1 and PD-L2 molecules on their cell surface, which attach to PD-1. When PD-L1 and PD-L2 interact with the PD-1 receptor on the T cell, the T cell is inactivated and cannot do its job of killing the cancer cells. Jemperli binds to the PD-1 on the T cells in a way that blocks PD-L1 and PD-L2 from interacting with the PD-1 receptor. This blockade on PD-1 allows the T cells to activate and to attack and kill cancer cells.
