The next step in the most revolutionary cancer therapy: producing it yourself with a simple injection.

A few weeks ago, at La Paz Hospital in Madrid, an immunotherapy treatment saved the life of a girl suffering from a very rare disease. This was one of the most recent successes of CAR-T cells , a drug based on the patient's own white blood cells that are modified in the laboratory to selectively attack the cells that cause the disease, whether cancer or an autoimmune disorder, as was the case with the patient in Madrid.

American immunologist Carl June, inventor of these treatments for blood cancers such as leukemia and lymphoma, compares their effects to a biblical miracle: the resurrection of Lazarus . CAR-T cells have been able to achieve spectacular cures in thousands of patients who were given up for dead, one of the greatest medical achievements of recent decades.

June is leading a study this Wednesday that could take these treatments to a new level. This therapy requires extracting T lymphocytes, a type of immune cell, from the patient, introducing genetic changes into them using viruses as a launchpad, causing them to multiply until they number in the millions, and then injecting them into the patient. This entire process is complicated and can be very expensive, which partly explains why commercial versions of these treatments sell for hundreds of thousands of euros. June himself explained in an interview with EL PAÍS that one of his goals is to lower their price.

The American immunologist signed a study today exploring a new experimental therapy for patients to produce CAR-T cells within their bodies. These are lipid nanoparticles containing small fragments of messenger RNA, a structure very similar to that of COVID vaccines . The RNA fragment contains the information for T lymphocytes to develop the ability to identify and eliminate malignant cells, in this case B lymphocytes, which can cause both hematological cancers and autoimmune diseases. The work is published in Science , a benchmark for the best science in the world.

The team has demonstrated that the treatment reprograms T lymphocytes and fights malignant cells in cell cultures from patients with autoimmune diseases. They have also shown that this injection is capable of eliminating blood tumors in mice and rats with leukemia, and also "resetting" the immune system of non-human primates, similar to what conventional CAR-T cells have achieved in humans with cancer and autoimmune diseases .

Those responsible for the work believe that this step will be key to democratizing these therapies. June's team at the University of Pennsylvania signed the study with scientists from Capstan , an American biotechnology company. The company has just announced the start of the first phase of clinical trials in patients suffering from autoimmune diseases mediated by B lymphocytes. June is one of the scientific founders of Capstan, along with Drew Weissman, co-inventor of the COVID vaccines, for which he received the Nobel Prize in Medicine in 2023 with biochemist Katalin Karikó .

If commercialized, these injections could drastically reduce the price of these treatments to around €5,000 per dose, according to the CEO of one of the most advanced companies in this field, Interius BioTherapeutics.

Because they are RNA -based, these types of CAR-T cells do not cause permanent genetic changes in patients, which is seen as an advantage. However, this also means that their effects cannot last for years, even decades , as with conventional CAR-T cells, but possibly months, which would require recurring doses throughout life, with the associated costs.

"These are impressive results," celebrates Ignacio Melero , professor of Immunology at the University of Navarra and co-director of Clinical Immunology and Immunotherapy at the Clínica Universidad de Navarra, who was not involved in the study. The work "This methodology holds extraordinary promise for treating some autoimmune diseases in cases refractory to standard treatments. For example, systemic lupus erythematosus , polymyositis, scleroderma, Sjögren's syndrome , and perhaps rheumatoid arthritis. It may not yet be an approach that can compete with conventional CAR therapy for treating leukemia or lymphoma, but with proper optimization, it could be feasible," he adds.

“It's an important study,” agrees Manel Juan , head of the Immunology Department at the Hospital Clínic in Barcelona, ​​where the successful public CAR-T that saved the girl from Madrid was developed and has already been applied to half a thousand patients with hematological tumors. “It seems possible to achieve the effect achieved by conventional CAR-T in autoimmune diseases, but without the risk of having permanent cells. Instead, through this system, it's transient, achieving the same effect with several doses,” he reasons. The doctor explains that two preliminary trials in China have shown that this approach has achieved complete remissions in two patients with hematological cancer. “In principle, the possibility of scalability, of increasing the number of productions for use in more patients, could reduce prices. But we already know that in the end, costs and prices are very different and depend on how they are managed by the different companies ,” he adds.