T-cell immunotherapy tied to 10-year remission in two leukemia patients, study finds
Two people with leukemia achieved remission over a decade after being infused with CAR-T cells, immune cells that had been modified in a lab, according to a new study. The findings suggest that this approach could be a long-term therapy for leukemia and researchers describe it as a possible cure.
Chimeric antigen receptor or CAR-T cell therapy may be a curative regimen for chronic lymphocytic leukemia, according to the researchers, who announced their findings in a news briefing this week. Chronic lymphocytic leukemia accounts for about a quarter of new cases of leukemia.
CAR-T cells are an immunotherapy treatment designed to treat leukemia by harnessing the body’s own immune system to target the cancer. The therapy sends a patient’s immune cells to a lab to be genetically modified using a virus and gives the cells the ability to recognize and kill the source of the cancer.
The new study describes two distinct phases that the patients went through. They had an initial phase represented by CD8+ or CD4−CD8 CAR-T cells expressing a marker called Helios and then a shift into a long-term phase of remission dominated by the CD4+ CAR-T cell population.
Researchers from the University of Pennsylvania and the Novartis Institute for Biomedical Research studied the long-lasting T cells in the two people with leukemia who were in complete remission in 2010 after they had been infused with the cells as part of a Phase 1 clinical trial. The two remain in remission more than 10 years after the infusion, the researchers noted.
They said this type of immunotherapy can come with serious side effects, though therapies have become safer over the years and are given to hundreds or thousands of people a year.
One side effect is tumor lysis syndrome, a phenomenon where you kill large numbers of cancer cells all at the same time and they spill their contents into the blood, and that can make people quite sick. Tumor lysis syndrome can cause electrolyte abnormalities and damage to the kidneys.
Another side effect is cytokine release syndrome, which gives people a severe flu-like syndrome, with very high fevers, nausea, vomiting, and muscle and joint pain.
The third major side effect is a neurologic toxicity, leading to difficulty speaking or thinking clearly. In some situations, people can become comatose or develop seizures, but the majority of cases resolve on their own.