Cancer drug checkpoint inhibitors – Cancer drug treatment, chemotherapy, began in the 1940’s. It has since boomed into a multi-billion-dollar industry with over a hundred cancer drugs divided into many subcategories that can target the cancer at the DNA level, at different points in the cellular growth cycle, or can even encourage the body’s own immune system to recognize the cancer for the threat it is and attack appropriately.

How checkpoint inhibitors work

Most people are familiar with the idea of vaccines and how they trigger an immune response within the body so that the body recognizes a particular type of invader. The tetanus vaccine, for example, is administered and the body mounts a defense against it, then if tetanus enters the body at a later time the body is ready with its heightened response and is able to quickly recognize and fight of the tetanus bacterium.

Checkpoint inhibitors don’t work quit the same way but they do depend on the immune system in a way that other cancer drugs do not. The immune system is the body’s way of fighting off disease. In order to do this, the cells in the immune system need to be able to recognize the difference between the body’s own cells and invaders such as viruses and bacteria that need to be attacked and dispelled from the body. In order to make this identification, the body has checkpoints on some of its immune cells. When these checkpoints are turned off, the immune response which is a complex chain reaction of events does not even begin. Some cancers are able to push this off switch and thus escape the body’s defenses. What if there was a way to turn that switch back on so the body’s immune response would be in full force against invading cancer? It seems that the new check point inhibitor drugs may be able to do just that.

PD-1 or PD-L1 drugs

PD-1 is the marker on the T immune cells in the body and PD-L1 is the marker on the tumor cells, when these two bind together the body’s immune response is greatly inhibited because the body thinks it’s identifying itself instead of an invading disease. These two types of drugs, PD-1 and PD-L1 stop the connection from either side. When they are not able to connect through these cellular markers the body appropriately identifies the cancer in the body as an invader instead of a friendly and attacks it.

Common cancer drugs

The most common type of cancer drugs include categories such as: anti-tumor antibiotics, alkylating agents, anti-metabolites, mitotic inhibitors, corticosteroids (often simply called “steroids”), hormone therapy or immunotherapy. Checkpoint inhibitors fall under the immunotherapy category.

New Cancer drugs

Checkpoint inhibitors or immune checkpoint inhibitors as they are commonly called currently include specific drugs such as: Atezolizumab (Tecentriq), Avelumab (Bavencio) and Durvalumab (Imfinzi) Pembrolizumab (Keytruda) and Nivolumab (Opdivo).

How Much Do Checkpoint Inhibitors cost?

While the answer does vary greatly depending on the drug and duration of treatment invariably the answer is still: not cheap. Imfinzi, for example, a checkpoint inhibitor used to treat bladder cancer is going for 180,000 dollars annually at wholesale. Others can be even higher.

More details

No cancer drugs are without their own set of side effects and checkpoint inhibitors are no exception. The common side effects are: cough, nausea, fatigue. In addition, immune, related adverse events (irAE) are a concern with this drug category. When the drug is taken the body is uniquely vulnerable to attacking itself particularly in the organs. While these reactions/side effects are less common they are still a major concern.

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