Positive results arrive from an extraordinary experimental immunotherapy trial performed in the United States. A woman’s own lymphocytes were taken and used to fight the cancer that had spread throughout her body. Two years later, the woman is still cancer free.
Immunotherapy: The New Frontier
A new approach to fighting cancer has been developed in the last few years- immunotherapy. The procedure uses the patient’s own immune system to ward off the disease. The two, most effective approaches are currently:
- Drugs that activate cells
- Therapy based on the direct use of immune cells
In the second approach, the patient’s tumor infiltrating lymphocytes (T-cells) are extracted from the patient’s blood or the tumor, after which the immune cells are screened to find only those that are strong enough to identify and attack the cancer cells. The T lymphocytes extracted from the tumor are grown in a lab and then injected back into the patient’s body. To date, the success of immunotherapy treatment can vary depending on the type of cancer. With breast cancer, clinical experiments based on the use of medication did not show significant results, for this reason experiments were performed directly on immune cells, leading to the immunotherapy trial in the U.S.
Small Great Miracle
The results, however, were only obtained on one patient and mustn’t provide false hope. Even still, the trial, published in Nature Medicine under the auspices of the National Cancer Institute, gained great international attention for its possible future implications. The fact is that the immunotherapy experiment brought about the complete durable regression of metastatic breast cancer, which had been unresponsive to all other treatments. This experimental therapeutic strategy is based on adoptive cell transfer (ACT), a type of treatment that has already been successful in patients with melanomas, tumors characterized by a large number of somatic mutations, but until today had given poor results in a series of other tumors with a low number of mutations.
The American researchers, led by Steven A. Rosenberg, Chief of the Surgery Branch at NCI’s Center for Cancer Research, developed a type of ACT that uses tumor-infiltrating lymphocytes (TILs) to selectively destroy the mutations present in cancer cells. The hypothesis, which was verified in only one case, was that treatment could reduce the size of epithelial tumors. TIL expansion is obtained first by removing the tumor-infiltrating lymphocytes from the patient’s tumor. TILs capable of recognizing tumor mutations are then isolated and billions are reproduced in vitro. These TILs are then injected back into the patient’s body, which, meanwhile, has undergone treatment to deplete remaining lymphocytes, in order to obtain a more powerful immune system response to fight the cancer.
Rosenberg and his colleagues experimented this treatment on Judy Perkins, a 47-year old woman who was diagnosed with untreatable breast cancer. The experiment was a complete success. The T cells completely eliminated the cancer and the metastases and the woman is still cancer free today, even though she did not undergo additional oncological treatments.
The strong point of this new strategy is that it is not specific to only one type of tumor. This form of immunotherapy only attacks mutations, the same ones that cause the cancer are in fact the same ones that destroy it after having undergone transformation through this treatment. “Because this new approach is dependent on mutations, not on cancer type, in a sense it is a blueprint we can use for the treatment of many types of cancer”, says Rosenberg. Similar results have recently been observed in patients with other types of epithelial tumors, an extremely important finding considering that until now ACT had not been so successful in these types of cancers.
If these results are confirmed, it will be a major development in the fight against cancer.
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