A very promising treatment for breast cancer

Breast cancer is most common in women; he is also the deadliest. Between 10 to 20% of them are qualified as HER2+ because the malignant cells have an abnormally high quantity of HER2 receptors on their surface, activated by growth factors. These receptors give cancer a non-negligible advantage: it proliferates rapidlyand less subject toapoptosis – the phenomenon of cell death – and surrounds itself with many blood vessels to ensure its supply of oxygen and nutrients.

An important therapeutic target, the search for overexpression of HER2 is systematic in women with breast cancer. Preventing the activation of HER2 means limiting the growth and proliferation of cancer. The treatment strategy for HER2+ breast cancers is based on two elements: a monoclonal antibody that binds to HER2 and blocks its activation and a molecule cytotoxic chemical. Several combinations are available in the market and prescribed depending on the patient’s health condition and cancer response.

Among the therapeutic arsenal available, the first-line treatment may consist of trastuzumab (also known as Herceptin), the monoclonal antibody and a taxane, the cytotoxic molecule. Without conclusive results, a combination of trastuzumab and emtansine, a molecule that inhibits the assembly of microtubules, a central element of cytoskeleton, can be used. Finally, in the third line, a combination of trastuzumab with deruxtecana molecule that interferes with topoisomerasea enzyme interacting with theDNA.

Improved overall survival with trastuzumab-deruxtecan

As part of theclinical test Destiny-Breast03, an international team of researchers reassessed the use of trastuzumab-deruxtecan as a second-line treatment, and compared its benefits and safety to those of the standard treatment, trastuzumab-emtansine. According to the results of phase 3 of the investigations, appeared in The New England Journal of Medicinetrastuzumab-deruxtecan significantly increases progression-free survival in patients with HER2+ breast cancer.

They are 524 patients to have been randomly assigned to one of the two groups. The latter all received a treatment composed of trastuzumab-deruxtecan which did not work. The results show that 75% of patients treated with trastuzumab-deruxtecane have progression-free survival at 12 months, compared to only 38% of those treated with trastuzumab-emtansine. Overall survival is also better with trastuzumab-deruxtecane: 94.1% of patients were still alive 12 months after this treatment compared to 85.9%.

Significant side effects

Nevertheless, trastuzumab-deruxtecan induces many more side effects than trastuzumab-emtansine. Almost all patients (98.8%) reported them during the clinical trial, almost half of which were stage 3 or 4 adverse events. Among the most frequent, the scientists noted the appearance of illness and pulmonary infection. More than 10% of patients treated with trastuzumab-deruxtecan are affected compared to only 1.4% of those treated with trastuzumab-emtansine. Despite its significant side effects, second-line trastuzumab-deruxtecane actually increases patient survival and reduces the risk of progression.