CAR-T Therapy & Brain Fog: New Study Findings
- A Stanford Medicine study has shed light on why some cancer patients experience "brain fog" following CAR-T cell therapy, a type of immunotherapy.
- Michelle Monje, identifies potential strategies for reversing this cognitive impairment, offering hope for improved recovery after cancer immunotherapies.
- CAR-T cell therapy involves modifying a patient's immune cells to target and destroy cancer cells.While generally mild, the resulting cognitive impairment can be frustrating and persistent.
A groundbreaking Stanford study reveals the link between CAR-T cell therapy and cognitive impairment, commonly known as brain fog. This vital research identifies the cellular mechanisms behind these issues, mirroring those seen in chemotherapy and infection-related brain fog.Find out how researchers successfully reversed this impairment in mice using targeted compounds,offering hope for future treatments. This News Directory 3 article delves into how CAR-T cell therapy, used to fight various cancers, can lead to frustrating and persistent cognitive issues. Learn about the role of microglia and the damage to myelin. Discover what’s next for those seeking to understand and address the long-term effects of this life-saving therapy.
CAR-T Cell Therapy’s role in Brain Fog Unveiled by Stanford Study
updated June 18, 2025
A Stanford Medicine study has shed light on why some cancer patients experience “brain fog” following CAR-T cell therapy, a type of immunotherapy. The research, primarily conducted on mice, indicates that CAR-T cell therapy can lead to mild cognitive impairments independent of othre cancer treatments. The study pinpoints the same cellular mechanism responsible for cognitive issues arising from chemotherapy and respiratory infections.
The study, led by Dr. Michelle Monje, identifies potential strategies for reversing this cognitive impairment, offering hope for improved recovery after cancer immunotherapies. Anna Geraghty and Lehi Acosta-Alvarez are the lead authors of the study.
CAR-T cell therapy involves modifying a patient’s immune cells to target and destroy cancer cells.While generally mild, the resulting cognitive impairment can be frustrating and persistent. Monje’s team successfully reversed this impairment in mice using compounds similar to existing or developing medications.
The therapy, approved in 2017 for acute lymphoblastic leukemia, is now used for other blood cancers and is being tested for solid tumors. Monje’s team is also conducting a trial of CAR-T cells for brain stem and spinal cord tumors in children.
Researchers examined mice with tumors in various locations to understand how tumor location and immune responses affect cognitive impairment after CAR-T therapy. Cognitive tests, such as observing responses to new objects and maze navigation, were performed before and after treatment.
The study found that CAR-T therapy induced mild cognitive impairment in mice regardless of whether the cancer originated in the brain, spread to it, or remained elsewhere in the body. Mice with bone cancer and minimal inflammation were the only exception.
The research revealed that microglia, the brain’s immune cells, play a crucial role. Activated microglia release inflammatory molecules that harm oligodendrocytes, which are responsible for producing myelin, the insulation around nerve fibers. Damage to myelin impairs nerve signal transmission, leading to cognitive decline.
Analysis of brain tissue samples from human subjects in a CAR-T cell trial confirmed similar dysregulation of microglia and oligodendrocytes. In mice, researchers reversed cognitive problems by depleting microglia or blocking chemokine signals, which are molecular signals that can cause damage.
“CAR-T cell therapy is enormously promising: We are seeing long-term survivors after CAR-T cell therapy for aggressive cancers, saving patients who would otherwise have died,” said Monje. “we need to understand all its possible long-term effects, including this newly recognized syndrome of immunotherapy-related cognitive impairment, so we can develop therapeutic approaches to fix it.”
What’s next
Monje said researchers are exploring how to safely implement these strategies in