Professor Michel Sadelain is widely regarded as one of the most influential figures in modern medicine and a pioneer behind a paradigm shift in cancer treatment through harnessing the power of the immune system. Born in France, he began his medical journey by earning his medical degree from the University of Paris, before moving to Canada to specialize in immunology, where he obtained his PhD. He later joined the Massachusetts Institute of Technology (MIT), where his growing interest in genetic engineering took shape—an academic path that ultimately led to groundbreaking therapeutic innovations. These contributions were recognized with the King Faisal Prize in Medicine in 2025, in honor of his pioneering work in the development of CAR-T therapies. In New York, Professor Sadelain established his first research laboratory at a specialized cancer center, dedicating his efforts to advancing T-cell engineering technologies that enable immune cells to precisely recognize and attack cancer cells. This work culminated in the launch of the first clinical trials involving patients in 2007, followed by official regulatory approval of this form of therapy in 2017, paving the way for its widespread adoption worldwide. To date, tens of thousands of patients have benefited from this innovative treatment. In Saudi Arabia, King Faisal Specialist Hospital & Research Centre began offering genetically engineered T-cell therapy in 2020, becoming one of the first centers in the region to provide this advanced modality. Similar CAR-T programs have also been integrated into clinical services at the National Guard Hospital. In this interview, we put a series of questions to Professor Michel Sadelain, exploring the origins of the idea, the scientific challenges encountered along the way, the role of healthcare practitioners in driving innovation, and his vision for the future of immunotherapy in the decades to come. | | | - Welcome, Dr. Sadelain. How did the idea of using genetically modified T-cells (CAR-T) first emerge in your work? At what point did you realize this concept could redefine cancer treatment?
I was pursuing my doctoral (PhD) studies in Immunology (in Canada, after having obtained my medical degree [MD] in France) and became aware of the limitations of our immune system to fight cancer. I began to think that we should “educate” our T cells rather than stimulate some of the T cells we happen to harbor through the use of vaccines. This “education” had to come into the T cell in the form of a “genetic instruction”, telling the T cell what molecule to recognize and what cells to eliminate. - What were the main challenges you faced in the early stages of developing this therapy, and what was the most significant obstacle you managed to overcome?
This concept was not well received initially because drugs, vaccination and antibodies were the preferred therapeutic tools of immunologists and oncologists, not cells; because it made use of synthetic receptors (that we named CARs) rather than natural receptors; and because it relied on genetic engineering (which some feared in those days, though it is well accepted and ubiquitous today). - Many pioneering ideas remain confined to laboratories. How did you succeed in translating this therapy from experimental research into clinical application?
Once we demonstrated the efficacy and the feasibility of engineering human CAR-T cells to treat cancers in mice (our landmark study was published in 2003), we knew this approach had to be tested in patients. There was no industry interested in this approach and so we had to do it ourselves. I was fortunate to have a passionate lab and a remarkable collaborator, Dr Isabelle Riviere, who together pieced together a process that accepted by the FDA and was led to the first CAR-T cell trial targeting CD9. We infused the first patient with CD19 CAR-T cells in June 2007. | | | - How have your research and achievements contributed to serving humanity, and where do we see their impact in everyday life?
Genetically engineered T cells have produced remarkable responses in patients with blood cancers that were resistant to all previous treatments. These patients were essentially considered beyond hope. What is striking is that a single dose of these cells has been able to eliminate most cancer cells in a large number of patients, with some achieving complete remission without the need for additional therapy. For this reason, I refer to them as “living drugs,” because they persist inside the patient’s body and continue to fight cancer for weeks or even months. More recently, this approach has also begun to be used in the treatment of autoimmune diseases, with highly promising results. - As both a researcher and a physician, when did you learn to become an innovative doctor? And how can healthcare practitioners balance clinical work with scientific research, despite the difficulty of this path?
Medicine is a beautiful profession, with many different angles – from family medicine to hospital care to laboratory research. All of these roles are important. I liked taking care of patients but was more attracted to research : inventing tomorrow’s medicine rather than practicing today’s state-of-the-art. Medical research is not an easy path, but it is intellectually very rewarding. - Researchers and healthcare practitioners are often seen as belonging to two separate worlds. From your perspective, how can hospital-based physicians contribute to innovation even if they are not full-time researchers?
healthcare practitioners in general—play a central role in the development of new therapies. They care for the first patients to receive these treatments and monitor side effects or toxicities that may not be fully predicted by preclinical studies. They also observe which patients respond to therapy and which do not, which is essential for improving treatments and developing next-generation approaches. In addition, clinicians are able to compare available therapies and determine which option is most appropriate for each patient. - What advice would you give to healthcare practitioners who have a passion for medical research?
They should acquire rigorous scientific discipline, integrate emerging technologies into their work, focus on big questions, and never lose sight of the ultimate goal: serving humanity. - Finally, how would you like your scientific legacy to be viewed in twenty or thirty years? And what message would you like to convey to the next generation of innovators in the healthcare sector?
We have helped introduce the concept of “engineered immunity” into clinical practice, based on genetic engineering and artificial receptors. This approach opens broad horizons for teaching immune cells how to treat—and potentially cure—cancer, as well as autoimmune diseases and other conditions, such as difficult infections or challenges in organ transplantation that were once considered unsolvable. Innovation in research and clinical practice has always been a passion for healthcare professionals. Today, we possess extraordinary tools, ranging from advanced molecular analysis and imaging to artificial intelligence and cellular therapies. These tools herald an unprecedented acceleration in medical discoveries in the years ahead—a prospect that inspires both excitement and optimism. Click here to learn more | | |
