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Immune Checkpoint Blockade: a Breakthrough in Cancer Treatment!

3 min read

2018 Noble Prize in Physiology and Medicine is given for the discovery of “Immune Checkpoint Blockade” therapy. Dr. James P. Allison and Dr. Tasuku Honjo are the two scientists who are awarded for their extensive work that brought about the onset of this treatment. I for one don’t really keep up with Noble prizes because all the technical details go bouncer over my head, but this news is worth knowing as it is pioneering a new wave of treatments in the cancer treatment.

So, what is this “Immune Checkpoint Blockade” therapy?

To know that we first need to understand (in an extremely simplistic way) how the immune system works.

The immune system is your body’s defense system that helps it fight off diseases, infections, allergies etc. It is perhaps the most complex of all of the body’s systems as it involves multiple organs (lymphatic system, Blood Cells, tonsils, digestive system, spleen) and it is active at every front of the body and inside every tissue, ready to defend it.

Like an antivirus scans your system, looking for all kinds of malwares, checks it against the database and then takes appropriate action to remove them. As they fight more and more malwares, the database gets richer, helps it defend the system against future attacks. The immune system works a lot like an antivirus!

Now think about cancerous cells and tumors, scientists always hypothesized that technically immune system should be able to attack and destroy them. Wouldn’t that be perfect? But it’s not so simple

Immune response against any bacteria, foreign body or even a tumor, is divided into two phases

  1. Initiation Phase: Immune system recognizes a threat
  2. Activation Phase: Innate immune system starts producing cytokines which signal to recruit immune cells for fighting the said infection

The immune system does not stay “ON” or active forever, once the infection is taken care of the immune response also turns off. Every activation phase is followed by a termination phase.  This process of immune response turning ON and OFF is a very fundamental process. During the termination phase, certain immune suppressor molecules are secreted that halt the immune response. Are you with me still? Yes? Good 🙂

Immune Checkpoint Blockade therapy focuses on suppressing the suppressor molecules, which means immune system can stay ON longer. This restores the capacity of CTL/Cytotoxic T-Lymphocytes (a White Blood Cell that kills cancer) to kill the cancer cells.

 

Dr. Allison’s Research

Dr. Allison who is currently working at M D Anderson Center For Cancer Research is known for his work on CTLA-4 (cytotoxic T-lymphocyte-associated protein 4), an immune suppressor/immune checkpoint protein. He discovered that blocking the signaling of CTLA-4 improved immune response against cancerous tumors. His research led to the development of Ipilimumab, a drug that has given great results in treating advanced melanoma (skin cancer)

 

Dr. Honjo’s Research

Dr. Honjo who is a professor in the Department of Immunology and Genomic Medicine at Japan’s Kyoto University Graduate School of Medicine discovered PD-1 (Programmed Cell Death Protein-1) back in 1992. PD-1 is also an immune suppressor/immune checkpoint protein. And by blocking PD-1, the immune response against cancerous tumors can be improved. In fact, his research led to the development of two very important drugs, pembrolizumab (Keytruda) and nivolumab (Opdivo). These two are also approved for use in advanced melanoma, however, more research is underway that shows their efficacy in treating lymphoma, lung cancer, and renal cancer.

 

What these drugs ARE?

These are drugs based on immune checkpoint blockade mechanism. They block the actions of immune-suppressing proteins and by doing so they restore the capacity of cancer killer lymphocytes.

 

What these Drugs ARE NOT?

They are not a cure for cancer. They are not shown to reverse or cure cancer completely! But in conjunction with chemotherapy, radiation, genetically targeted drugs, these immune checkpoint blockers can help prolong a patient’s life and also enhance the quality of life.

 

Are these drugs Available in India?

Yes, but they are very expensive. You can buy them online for certain or ask your local pharmacist about them.

 

Any side effects?

Yes, as with any medicine, these two also come with some unwanted effects. Autoimmunity is one of such effects (thanks to continuously “ON” immune system, it can start attacking your own cells!)

 

What does the future stores?

This is an ongoing field of research and scientists are discovering more and more immune checkpoint blocking proteins. With time the drugs will get more sophisticated reducing the side effects, and with mass production or generic brands coming out hopefully, the prices will drop too.

 

Thank you for staying with me till the very end. Now go brag about this newfound cool information to your friends or SO 😛

 

Soniya Nikam, MS, RD.

She is a Registered Dietitian who does not believe in dieting; She has a Master’s Degree in Nutrition but she is not your “I know it all Nutrition Guru!”; She loves food but loves talking about food even more. Her articles are a direct reflection of her personal quest where nutrition science meets real life! Oh, and she is owned by a 3 m.o. naughty kitten 🙂

Soniya Nikam, MS, RD.

Soniya Nikam, MS, RD.

She is a Registered Dietitian who does not believe in dieting; She has a Master's Degree in Nutrition but she is not your "I know it all Nutrition Guru!"; She loves food but loves talking about food even more. Her articles are a direct reflection of her personal quest where nutrition science meets real life! Oh, and she is owned by a 3 m.o. naughty kitten :)

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