Keytruda (pembrolizumab) is prescribed to treat melanoma and other conditions by reviving the body’s immune system. Your response to this drug may vary based on your medical history, diagnosis, and other medications you’re taking.
Keytruda belongs to a class of medications called programmed death receptor-1 blocking
antibodies (PD1-blocking antibodies). These drugs work by binding to certain parts of cells. This action inhibits certain cells called T cells from multiplying. It then inhibits certain proteins from producing.
The way a drug works is known medically as its mechanism of action. Keytruda’s mechanism of action is twofold. It refreshes the activity of your immune system. By doing so, it then stops cancer cells from growing.
To start, the drug attaches to the PD1 protein. Once it attaches, it blocks the action this protein has with another protein called programmed death ligand-1 (PD-L1).
PD1 and PD-L1 work together to stop your immune system from performing some specific actions. In some cancers, these proteins work together too much. With this overactivity, your immune system has difficulty detecting which cells carry cancer.
Once Keytruda blocks the action between these two proteins, it refreshes your immune system. This helps your immune system detect cancer cells and stop them from growing and spreading.
Once you start treatment with Keytruda, it starts working right away to refresh the activity of your immune system. This is how the drug works to treat cancer.
But it isn’t known how long your immune system needs to be refreshed so the drug can treat the cancer. Throughout your treatment, your doctor will check how well the cancer is responding to the drug. If you’re taking other cancer medications, they also could affect how long Keytruda takes to work.
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