The largest clinical study ever conducted to date of patients with advanced leukemia found that an incredible 88% of patients entered remission after being treated with genetically modified versions of their own immune cells. It’s like the medicine of tomorrow – today; and it’s super effective.
“These extraordinary results demonstrate that cell therapy is a powerful treatment for patients who have exhausted all conventional therapies,” said Michel Sadelain, MD, PhD, Director of the Center for Cell Engineering at Memorial Sloan Kettering and one of the study’s senior authors. “Our initial findings have held up in a larger cohort of patients, and we are already looking at new clinical studies to advance this novel therapeutic approach in fighting cancer.”
Investigators from Memorial Sloan Kettering Cancer Center have reported these encouraging results, despite the very aggressive nature of the disease. Adult B cell acute lymphoblastic leukemia (B-ALL) is a type of blood cancer that develops in B cells and is very difficult to treat. Even when you get good results initially, most of the patients just relapse.
Patients with relapsed B-ALL have few treatment options; only 30 percent respond to salvage chemotherapy. Basically, they need a bone marrow transplant; without that, they face limited options for survival. But this study shows great prospect, and if things continue to move on like this, we may very well see it applied to more and more patients.
In this study, 16 patients with relapsed B-ALL were given an infusion of their own genetically modified immune cells, called T cells. T cells or T lymphocytes are a type of lymphocyte (itself a type of white blood cell) that play a central role in cell-mediated immunity. Through genetic engineering, these cells were “reeducated” to track and hunt down cancer cells that contain the protein CD19.
The overall response rate was 88 percent, but even those with detectable disease prior to treatment had a complete response rate of 78 percent, far exceeding the effects of chemotherapy.
The medicine of the future
Giving patients treatments based on their own, genetically engineered cells, is a relatively new idea – and only recently have researchers been able to actually implement it. The main problem with our bodies fighting cancer is that unlike a flu virus for example, our immune system doesn’t recognize cancers as foreign, and therefore is at a disadvantage when it comes to recognizing and fighting the enemy. For more than a decade, researchers at Memorial Sloan Kettering have been exploring ways to reengineer the body’s own T cells to recognize and attack cancer. In 2003, they were the first to report that T cells engineered to recognize the protein CD19. Back in 2003, they were using this treatment to cure cancer in mice – more than 10 years later, in 2014, they finally report results in human clinical trials.
“Memorial Sloan Kettering was the first center to report successful outcomes using this CD19-targeted approach in B-ALL patients,” said Renier Brentjens, MD, PhD, Director of Cellular Therapeutics at Memorial Sloan Kettering and one of the study’s senior authors. “It’s extremely gratifying to witness the astonishing results firsthand in my patients, having worked for more than a decade developing this technology from the ground up.”
The study goes the whole nine yards, and also provides patients with a thorough guideline on how to deal with the side effects of cell therapy, which can include severe flu-like symptoms such as fever, muscle pain, low blood pressure, and difficulty breathing, referred to as cytokine release syndrome.
Further research is required to further test the validity of this treatment, but I’m happy to announce that studies to test whether B-ALL patients would benefit from receiving targeted immunotherapy as frontline treatment are being planned.
M. L. Davila, I. Riviere, X. Wang, S. Bartido, J. Park, K. Curran, S. S. Chung, J. Stefanski, O. Borquez-Ojeda, M. Olszewska, J. Qu, T. Wasielewska, Q. He, M. Fink, H. Shinglot, M. Youssif, M. Satter, Y. Wang, J. Hosey, H. Quintanilla, E. Halton, Y. Bernal, D. C. G. Bouhassira, M. E. Arcila, M. Gonen, G. J. Roboz, P. Maslak, D. Douer, M. G. Frattini, S. Giralt, M. Sadelain, R. Brentjens. Efficacy and Toxicity Management of 19-28z CAR T Cell Therapy in B Cell Acute Lymphoblastic Leukemia. Science Translational Medicine, 2014; 6 (224): 224ra25 DOI: 10.1126/scitranslmed.3008226