A large study by researchers at Stanford Medicine has found that the risk of secondary blood cancers after CAR-T cell therapy -; a cell-based cancer treatment that exploded on the scene in 2017 as a treatment for intractable blood cancers -; is low, despite a Food and Drug Administration warning. In November 2023, the FDA issued a warning about a risk of secondary cancers -; particularly blood cancers -; that may be associated with CAR-T cell therapy. The warning was preceded by a rising tide of concern following reports of patients diagnosed with T cell cancers unrelated to the cancer for which they had been treated.
However, the study of over 700 patients treated at Stanford Health Care indicated that the risk is low -; around 6.5% in the three years after therapy. In the only case of fatal secondary T-cell cancer, researchers found it was likely due to the immunosuppression caused by CAR-T cell therapy, rather than the CAR- T cells .
The compromised immune system allowed pre-existing, but not previously detected, cancer cells to grow explosively in the patient. We wanted to understand this one rare case, so we analyzed all the patients treated with CAR-T cell therapy at Stanford with wide breadth and studied this single case extraordinary depth. We compared protein levels, RNA sequences and DNA from single cells across multiple tissues and time points to determine that the therapy didn't introduce the lymphoma into this patient; instead it was already brewing in their body.
