Why Immunotherapy was Awarded Nobel Prize in Medicine 2018?« Back to Questions List

Immunotherapy is all about harnessing the potential of immune system to attack cancer. Cancer is described as the emperor of all maladies. At present, two methods are followed in the treatment of cancer. Chemotherapy is the most popular treatment method and has been employed for decades. The medicine is very toxic and in the process of killing cancer cells, it also damages healthy cells causing weakness, diarrhea, severe pain, nausea and hair and weight loss. Immunotherapy, the other method is of the recent origin. Nobel prize in Medicine or Physiology 2018 was awarded to  James Allison of the University of Texas MD Anderson Cancer Center in Houston and Tasuku Honjo of Kyoto University in Japan  for discovering two different ways for removing the brakes of the immune system that prevent it from confronting tumor cells.

James Allison’s studies were based on the researches of French immunologists from the 1980s. T cells of the immune system attack cells that are identified as foreign by the body.  Allison and his team identified that a  key receptor on the surface of T cells,  called cytotoxic T-lymphocyte antigen 4  or CTLA-4, apply  the brakes on T cells, preventing them from launching  a severe attack on tumor cells. Cancer develops as the immune system fails to offend tumor cells, even when the tumor cells are growing at fast pace.  Allison’s researches were to block the blocker—the CTLA-4 molecule— to activate the immune system to fight cancer cells. .

In 1996, Allison published a paper in Science proving that antibodies against CTLA-4 erased tumors in mice. However, there were not many takers among pharmaceutical companies for the new method, as they feared side effects.  Hence, a small biotechnology company, Medarex, in Princeton, New Jersey got the opportunity for taking anti–CTLA-4 into people. They acquired the right to the antibody in 1999 and were the first to use it as a drug in 2011. The technique has now proved to be a convincing method in the treatment of cancer and many medicines like ipilimumab (brand name Yervoy), nivolumab (Opdivo) and pembrolizumab (Keytruda) are available in market.

Tasuku Honjo, in the early 1990s,discovered a molecule in dying T cells and named it programmed death 1, or PD-1.  He identified that PD-1 is another brake on T cells. The experiments by his team proved that the molecule could be targeted in cancer treatment. The clinical trials using PD-1 proved to be more effective in treatment of cancer with much lesser side effect compared to CTLA-4.

The cancer immunotherapies have transformed the treatment of certain types of cancer. It is now proven that types of tumors that were earlier considered as untreatable can be shrunk to almost nothing by adopting cancer immunotherapy technologies. Scientists now expect path breaking achievements in the treatment of cancer by combining different immunotherapies and by employing the drugs soon after diagnosis. It is also expected that the Nobel Prize for immunotherapy  will further promote researches to identify solutions on treatment of autoimmune diseases. 

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