Twenty patients with metastatic breast cancer will participate in the first clinical trial of an innovative immunotherapy with CAR-T cells that is being developed at the Hospital Clínic in Barcelona.
The therapy consists of extracting immune cells from patients' blood and modifying them in the laboratory so that they recognize a protein from tumor cells. A sufficient dose of immune cells directed against the cancer is then produced and transfused to the patients. This strategy is already used successfully to treat leukemias and lymphomas, but is not yet approved for any solid tumors such as breast tumors.
The project led by the Clínic will focus on HER2 (or HER2 positive) cancers, which represent between 20% and 25% of all breast cancer cases. These tumors are characterized by having a large amount of the HER2 protein in the membrane of their cells. The therapy will take advantage of this feature to direct T lymphocytes – the type of immune cells capable of destroying tumor cells – against the HER2 protein.
“Patients with metastases for whom all treatment options have already been exhausted will participate in this first trial,” reports Aleix Prat, director of the Institute of Cancer and Blood Diseases at Hospital Clínic.
The research project, which will last five years, will have funding of one million euros provided by El Corte Inglés. The project has been selected by the Spanish Association Against Cancer (AECC), which manages the donation from El Corte Inglés.
The first patients are expected to receive the treatment within approximately a year, reports Julio Delgado, principal investigator of the project and head of the Clínic's oncoimmunotherapy unit. First, the researchers must demonstrate that they can produce enough CAR-T cells directed against the HER2 protein, which is one of the requirements that the Spanish Agency for Medicines and Health Products (AEMPS) requires to authorize the clinical trial.
The first objective will be to determine the appropriate dose of CAR-T cells to administer. To do this, we will start with three patients who will receive a low dose. If there are no serious side effects, the other three will be continued, which will receive an intermediate dose. Then three others will receive a higher dose. From there it will be decided what dose to administer to the remaining eleven patients, who are expected to receive the treatment in 2026.
The first results of the clinical trial, in which the Doce de Octubre hospital in Madrid and the Clínica Universidad de Navarra will also participate, could be known in 2027. “Although the objective of a phase 1 trial like this is not to demonstrate efficacy, we trust in see signs that the therapy works,” declares Prat.
If it works, it could be useful to treat cancers of other organs that also have an excess of the HER2 protein, such as some stomach, colorectal, ovarian or lung cancers.
“Our goal is to develop the therapy to make it available to other hospitals at cost price,” Delgado declares. “There are CAR-T therapies approved in Europe that cost between 250,000 and 400,000 euros per patient. We need alternatives that are just as effective, no more toxic and at more reasonable prices.”
