A new study suggests that the gut microbiome may play a key role in the success of CAR T-cell therapy for patients with relapsed/refractory diffuse large B-cell lymphoma (R/R-DLBCL). Researchers studied 47 Asian patients and found that certain gut bacteria and metabolites were linked to both treatment effectiveness and side effects.
Patients who responded well to therapy had higher levels of the bacterium Bacteroides fragilis and increased activity in inosine biosynthesis pathways. Higher levels of inosine in the blood before treatment were associated with longer progression-free survival, as inosine appeared to enhance CAR T cells’ ability to kill cancer cells.
The microbiome also influenced treatment toxicity. Patients with fewer side effects had higher levels of “good” bacteria like Bifidobacterium and Faecalibacterium, which produce beneficial short-chain fatty acids. In contrast, those with severe side effects had higher levels of pro-inflammatory metabolites such as isovalerate. The findings suggest that gut bacteria may help predict both the effectiveness and safety of CAR T-cell therapy in lymphoma patients.