Dr. Lucia Del Mastro, who was awarded the Guido Venosta prize on the occasion of the Days of Research at the AIRC, explained in this interview given to Focus the functioning of trastuzumab deruxtecan, a new drug against breast cancer, composed of an antibody and a chemotherapy, which is also effective against difficult forms. We propose that interview again.
The enthusiasm of the doctors. At the beginning of June, at the American Society of Clinical Oncology (Asco) congress, a study was presented on a drug with a complicated name – trastuzumab deruxtecan – intended to change breast cancer therapy especially for the most difficult cases . The results, published simultaneously on the authoritative New England Journal of Medicine, were greeted with a standing ovation. An uncommon occurrence in a field where doctors are used to caution.
Because it’s important? There are several types of breast cancers, which doctors classify based on certain molecular characteristics. In fact, alongside traditional chemotherapy, more recently introduced drugs are precise and effective for some forms, but useless in others. The three types of breast cancers are:
HER2 positive tumors: they make up about 20% of all breast cancers and are distinguished by the presence of a high number of HER2 receptors, a protein that promotes cell proliferation. This receptor represents a target for some anti-HER2 drugs already on the market.
“luminal” tumors: they are characterized by the presence of receptors for estrogen hormones and progesterone and by the absence or scarce presence of the HER2 receptor. These cancers make up about 60% of all breast cancers and are treated primarily with anti-hormone therapy, possibly followed by chemotherapy.
Triple negative tumors: they have neither hormone receptors nor the HER2 receptor and make up about 20% of all cancers. They are generally more aggressive and are treated with chemotherapy possibly associated with immunotherapy.
About 50% of luminal tumors and 35-40% of triple negative tumors may have a small amount of HER2 receptors and are referred to as HER2-low. The anti-HER2 drugs on the market today are not useful against these forms, but the study just presented at the Asco congress has instead shown that trastuzumab deruxtecan can hit them with great effectiveness.
How the study took place. The research involved about 500 patients with HER2-low breast cancer, in metastatic stage and previously treated with the best available therapies.
Some of them received the new drug, while the others continued with the chemotherapy prescribed by the doctor. In patients treated with trastuzumab deruxtecan, the risk of disease progression was reduced by 50% compared with chemotherapy and survival was increased by approximately six months. Furthermore, in more than half of the cases there was a significant reduction in metastases, instead observed in only 16% of women treated with standard chemotherapy.
Most of the patients involved in the study had a hormone receptor positive tumor, but a small proportion had a triple negative type instead. The benefits were also seen in this group, but the finding needs to be confirmed with further research. The study also made it clear that the drug’s side effects are not negligible and require close monitoring.
The Days of Research Airc (Italian Association for Cancer Research), inaugurated on 28 October 2022 at the Quirinale by the President of the Republic Sergio Mattarella, take place from 6 to 13 November and have the aim of informing and raising awareness of the progress achieved in the field of prevention , cancer diagnosis and treatment