A balanced CAR-T cell metabolism driven by CD28 or 4-1BB co-stimulation correlates with clinical success in lymphoma patients

Chimeric antigen receptor (CAR) T cell therapy has led to unprecedented success in treating relapsed/refractory diffuse large B cell lymphoma (DLBCL). The most common CAR-T cell products currently in the clinic for DLBCL differ in their co-stimulation moiety, containing either CD28 or 4-1BB, which initiate distinct signalling pathways. Previous work has highlighted the importance of T cell metabolism in fuelling anti-cancer function. We have studied the metabolic characteristics induced by CD28 versus 4-1BB co-stimulation in patient CAR-T cells ex vivo. Our data show that in patients, CD28 and 4-1BB drive significantly divergent metabolic profiles. CD28 signalling endows T cells with a preferentially glycolytic metabolism supporting an effector phenotype and increased expansion capacity, while 4-1BB co-stimulation preserves mitochondrial fitness and results in memory-like differentiation. Despite this divergent programming, T cells in patients responding successfully to therapy were metabolically similar, irrespective of co-stimulator, suggesting that efficient fuelling of CAR-T cells in lymphoma requires a balanced metabolism. In contrast, CAR-T cells in non-responders were pushed to their metabolic extremes.