Research from Memorial Sloan Kettering Cancer Center (MSK) indicates that the timing of chimeric antigen receptor (CAR) T cell therapy may impact patient outcomes in large B cell lymphoma. The study found that patients receiving CAR T therapy in the morning had a better response compared to those treated later in the day. Published on January 5, 2026, in the journal Blood, this preliminary research suggests that timing based on the body’s circadian rhythms could enhance treatment effectiveness.
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The study examined over 1,000 patients who received CAR T therapy for large B cell lymphoma—constituting about one-third of non-Hodgkin lymphoma cases—at various hospitals across the United States, Europe, and Israel between 2017 and 2025. Co-corresponding author Dr. Roni Shouval, a bone marrow transplant specialist at MSK, noted that understanding the relationship between circadian rhythms and treatment outcomes could lead to improved administration strategies for CAR T therapy.
CAR T therapy involves collecting a patient’s T cells, modifying them in a lab to effectively target cancer cells, and then reinfusing them into the patient. Its success rates vary, with 50% to 90% of patients achieving remission, although long-term responses remain a challenge.
Previous research has shown that circadian rhythms influence not only sleep but hormone levels, metabolism, and immune function. Dr. Shouval highlighted that earlier studies on different immunotherapies indicated better outcomes when treatments were administered in the morning. This study is believed to be the first large-scale analysis assessing the timing of CAR T infusions regarding patient outcomes.
Findings revealed that 51% of patients treated before noon experienced progression-free survival at one year, compared to just 35% for those treated after noon. Co-corresponding author Dr. Kai Rejeski observed that treatments given later in the day were associated with lower CAR T cell expansion and increased levels of pathological inflammation, which may contribute to poorer outcomes.
Logistical factors often determine when CAR T patients receive treatment. Delays might occur due to necessary pre-treatment procedures or timing of lab deliveries. Should future research support the advantages of morning infusions, modifications in practice could optimize timing to align with patients’ circadian rhythms.
Despite these promising correlations, Dr. Shouval emphasized that the current study only shows association and not causation, calling for prospective studies to validate the findings. Future research will also investigate the timing of T cell collection prior to engineering, as this could influence their effectiveness.
Additional participating institutions included hospitals in Israel and Germany, with research supported by National Institutes of Health grants. Dr. Shouval and Dr. Rejeski have disclosed multiple grants and funding sources related to their work.