Immunotherapy is one of the most revolutionary therapies of recent years to fight cancer. Broadly speaking, it consists of making the immune system capable of detecting tumor cells and eliminating them . Not an easy mission because the malignant cells are masters in the art of disguise. They use telomerase, an enzyme that is present inside all cells and makes them go unnoticed by the immune system.
Within immunotherapy we can distinguish three strategies: strengthening the immune system, bispecific antibodies and CARs .
The first of the strategies has already been used to fight the so-called triple negative breast tumors.
Bispecific antibodies have the ability to adhere to two antigens and form a bridge between immune and tumor cells, that is, they actively direct immune cells against tumor cells . In this sense, Dr. Joaquín Arribas, director of preclinical research at the Vall d’Hebron Institute of Oncology (VHIO), and his team last year completed a project funded by Ausonia in which they developed a bispecific antibody therapy aimed at fighting against breast cancers known as HER2-positive , that is, those with very high levels of the HER2 protein, affecting approximately 20% of patients. Bispecific antibody therapy could not only work in these cases but also in tumors with very high levels of this protein, such as HER2-positive gastric ones (they represent 20% of gastric tumors).
“With the help of Ausonia, last year we finished a project in which we found a promising therapy for a type of breast cancer that affects approximately 20% of patients . In this second phase that we are starting now, we give this therapy a twist and what we will do is use the patient’s own immune cells , we will educate them so that they are able to find tumor cells and eliminate them in an effective way ”, stated Dr. Arribas at a round table organized by Ausonia and the AECC (Spanish Association Against Cancer) in Madrid.
What Dr. Arribas refers to with “educating” immune cells is CARs, “obtaining the patient’s immune cells, genetically modifying them so that they recognize tumor cells and, once modified, injecting them.” Asked if this technique could act as a vaccine, the doctor answers: “Without becoming a vaccine, the strategy of modifying the patient’s own immune cells could give very long-lasting responses , similar to those given by the vaccine.”
CARs have already been tested to fight some leukemias but not to fight solid tumors. “We hope that in the future it will be possible. In principle, it could be used against any tumor, although we started with HER2-positive breast tumors ”, Arribas tells us.
In the fight against breast cancer, the detection of the tumor in early stages is key because for certain breast cancer tumors there are very effective treatments. “ More than 90% of HER2-positive tumors are cured with available therapies, when detected early . Unfortunately in advanced stages the figures are not so positive, and only one in three patients survives to five years ”, Arribas concludes.
