Breast cancer: considerable progress in immunotherapy significantly delays life expectancy, even in the worst prognoses

An international study published on July 21 reveals that adding a type of immunotherapy, an antibody called pembrolizumab, to chemotherapy improves the overall survival of patients with advanced triple-negative breast cancer by 27%. worse prognosis in this type of cancer. Triple-negative breast cancer accounts for approximately 15% of all diagnosed breast tumours.

Proof of the advances in research and therapies, much progress has been made in 40 years in the treatment of breast cancer. Chemotherapy since the 1970s has demonstrated its ability to improve patient outcomes when applied after surgery. Hormonal treatments have also been added and more recently more effective targeted therapies have gradually reduced the impact of breast cancer.

However, there is a type of these cancerous tumors whose weaknesses are unknown, such as the so-called triple negative ones, because their cells do not have estrogen or progesterone receptors and produce little HER2, the protein regulating cell multiplication. They represent about 15% of breast tumors and are more common in women under 40, much more aggressive with a high risk of a poor prognosis.

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On July 21, 2022, the New England Journal of Medicine published the results of a study that offers a new treatment option for these patients. The trial, which involved 847 patients, showed that when an immunotherapy drug, an antibody called pembrolizumabis added to the usual treatment of these tumors with chemotherapy, the average survival increases by seven months in patients with advanced triple-negative cancer, from 16 to 23 months.

The study authors report that in patients with advanced triple-negative breast cancer whose tumors express the PD-L1 biomarker, the addition of pembrolizumab to chemotherapy results in significantly longer overall survival than chemotherapy alone. About 40% of patients with triple negative breast cancer have elevated levels of this biomarker.

PD-L1 is a protein that our body uses to identify healthy cells and prevent our own immune system, in addition to eliminating harmful viruses or bacteria, from acting against our own organism. This protective function is also used by certain tumor cells. These are real poisons in our body, and which pass under the radar of our immune defenses or therapeutic treatments.

Experimental treatments are being tested in people with poorer prospects, but researchers say they will offer more benefit in patients with less advanced tumors

Immunotherapeutic treatments, such as monoclonal antibody pembrolizumab, used in this study, are able to remove this mask from the cancer and expose it to the immune system. 40% of people with triple-negative breast tumors have elevated levels of this biomarker and could benefit from the new treatment.

However, tumor cells can escape this attack by expressing a protein called PD-L1 on their surface. PD-L1 functions as a “stop sign” and inactivates T cells before they attack.

Immunotherapy could unmask tumors hidden under the expression of proteins such as PDL1 and increase the effectiveness of other drugs.

This binding between PD-L1 and its receptors therefore constitutes an interesting therapeutic target for immuno-oncology. Indeed, blocking the PD-L1 protein can prevent cancer cells from inactivating T cells through the PD-1 and B7.1 receptors. T lymphocytes therefore regain their role in the detection and destruction of cancer cells.

In any case, this is revealed by the study carried out by Doctor Cortes’ team, which was published by the New England Journal Of Medicine and validated by their peers.

Still, the increase in seven-month survival recorded in the study “is the largest in the history of metastatic triple-negative breast cancer”.

According to the researchers, the combination of Trojans will be important with immunotherapy. The former are drugs that combine a targeted drug to deliver chemotherapy to the tumor and release the load there with greater intensity and fewer side effects.

The study conducted by Doctor Cortes was published by the New England Journal Of Medicine and validated by their peers. He can be contacted at [email protected] or at the International Breast Cancer Center, Marquesa de Vilallonga 12, Barcelona 08017, Spain.

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