On the case of Jimmy Carter: immunotherapy against cancer cases

the recent advertisement Former US President Jimmy Carter to forego hospital medical treatments and spend his remaining time in hospice care at home brings two important issues to public discussion. One is related to his cancer treatment in 2015 and the other to the will of a person to decide where and how he wishes to die. Today we will deal with the first topic.

On August 20, 2015, Carter reported, in a Press conferencethat they had found a tumor two centimeters in the liver. The study revealed that it was a malignant melanoma, one of the most aggressive cancers that a human being can suffer. He also had four brain tumors, considered metastases of the cancer in that organ.

Calmly and with a lot of resignation, Carter said that he was placing his health in the hands of God and his doctors, and that he would start brain radiation treatment that same day. Given a diagnosis of advanced level IV cancer (metastasis to distant organs) in a 90-year-old man, experts agreed that the prognosis was very guarded. According to the American Cancer Society, only one in five patients with this advanced stage of the disease live five years. Carter was not heard from again until four months later.

On Sunday, December 6, 2015, during his Sunday class at his church in Georgia, the former president reported that an MRI of his brain showed that the cancer had disappeared and that his doctors considered him free of the disease.

pembrolizumab

Days later it was learned that, in addition to the surgical removal of the liver tumor and treatment with brain radiation, Carter received four doses of a new drug called pembrolizumab, approved just a year before by the US Food and Drug Administration (FDA) for the melanoma cancer he suffered from.

Pembrolizumab belongs to a new category of drugs against cancer, immunotherapy, which is considered – along with surgery, radiotherapy and chemotherapy – the fourth treatment modality against this disease.

Remember that surgery tries to remove the tumor from the body, radiotherapy irradiates the cancer with X-rays to eliminate it and chemotherapy includes drugs that act directly on cancer cells for their reproduction.

“Immunotherapy drugs do not directly attack cancer cells, but instead stimulate the immune system to destroy them.”

By your side, the medicines of immunotherapy They do not directly attack cancer cells, but instead stimulate the immune system to destroy them. Pembrolizumab and several others in its class are smart drugs that harness the immune system’s natural ability to fight cancer to do the job of killing it.

Related to the immune system’s natural ability to fight cancer, let’s remember that the human immune system uses intelligent cells called T lymphocytes to patrol the body for cancer cells and destroy them, preventing tumors from growing. In other words, a natural function of the immune system is to stop cancer cells from growing.

It is very important that, during this patrolling of the tissues, the T lymphocytes differentiate between healthy cells and cancer cells, so that they respect the former and destroy the latter. This recognition of healthy cells is done with receptors called PS-1located on the surface of T lymphocytes. In order for them to recognize a healthy cell, they must bind to receptors PD-L1which are on the surface of healthy cells.

In other words, if during their patrol, the T lymphocytes encounter cells with PD-L1 receptors, they respect them, because they think they are not cancerous. The point is that cancer cells are very smart, because, in their eagerness to survive and perpetuate themselves, they produce and place a large number of PD-L1 receptors on their surface, to fool the T lymphocytes, and not be destroyed.

What pembrolizumab does is deactivate the receptor PS-1 o “healthy cell locator” of the T lymphocyte, thus ceasing to consider cancer cells that used the receptors “healthy” PD-L1 like shield.

The end result is that millions of lymphocytes are now capable of recognizing cancer cells by other mechanisms, and they destroy the tumor. Apparently, that was what happened with former President Carter, as his treatment with pembrolizumab was so successful that it completely eliminated cancer cells from his body, allowing him to remain cancer-free from 2015 to the present.

The cause of the ex-president’s terminal condition has not been revealed, but it is thought that his health began to deteriorate after he suffered a fall in October, for which he underwent brain decompression surgery. In other words, he would die for reasons unrelated to the cancer he was diagnosed with eight years ago.

The success of immunotherapy treatment was so great that, to this day, many people with cancer ask their doctors to “give them the same treatment that former President Carter received.”

Corollary

Immunotherapy is a rapidly advancing field, and while we’ve seen its role in cancer today, this type of therapy is now used in multiple branches of medicine. The great barrier to their massive use is the price of these drugs.

According to the website of the manufacturer of pembrolizumab, the price of each treatment, administered every three weeks, is US$10,683.52. Knowing that the treatment can be extended for 24 months if the disease does not progress before, the total cost can reach a minimum of US$256,404.48.