Routine Blood Test Can Predict Who Benefits Most from CAR T-Cell Therapy

Clinicians currently lack simple, early indicators to determine which patients are responding well and which may need alternative strategies. New evidence now shows that tracking immune cell levels in the blood after treatment can reliably predict survival and treatment response.

A study led by Fox Chase Cancer Center (Philadelphia, PA, USA), in collaboration with Temple Health (Philadelphia, PA, USA), focused on absolute lymphocyte count, a standard blood measurement reflecting the number of infection-fighting white blood cells circulating in the body. During CAR T-cell therapy, a patient’s T cells are collected, genetically engineered to recognize lymphoma cells, and infused back into the bloodstream. Because this treatment relies on immune activation, researchers examined whether changes in lymphocyte levels after infusion could reflect treatment effectiveness.

Investigators analyzed patients with relapsed or refractory non-Hodgkin lymphoma treated with axicabtagene ciloleucel, a commonly used CAR T-cell therapy. Absolute lymphocyte count was measured before treatment and repeatedly during the early post-treatment period to assess both baseline levels and the speed of immune recovery. This approach relies entirely on routine blood tests already available in hospital settings, requiring no specialized assays or additional clinical burden.

The analysis showed that patients with higher baseline lymphocyte counts had significantly better progression-free survival and overall survival. In addition, a faster rise in lymphocyte levels within the first 10 days after therapy was strongly associated with complete response and longer disease control. Patients whose lymphocyte levels peaked earlier also experienced more favorable outcomes, according to the findings published in the journal Blood.

Because absolute lymphocyte count is inexpensive and widely available, it could serve as a practical early marker to guide post-treatment decisions. Patients showing poor immune recovery could be identified sooner and considered for alternative therapies before relapse occurs. Researchers plan to evaluate lymphocyte trends in other CAR T-cell products and patient populations, with the goal of refining personalized treatment strategies in lymphoma care.

“If we see that a patient has low lymphocyte counts and might relapse, we can try another strategy,” said Dr. Helen Gandler, first author of the study. “Finding a kinetic marker that doesn’t take a lot of resources to check but could still make a real difference in a patient’s course of treatment is exciting.”

Related Links:
Fox Chase Cancer Center
Temple Health