Preliminary results reported in Nature Medicine showed that a redesigned CAR T-cell therapy produced complete response with no severe toxicities in 25 patients with refractory B-cell lymphoma.

A single infusion of the therapy, which targets the CD19 antigen, led to complete responses in 6 of 11 patients treated with the highest dose. It also induced significantly less cytokine production, and none of the patients developed severe neurologic toxicities or grade 2 or higher cytokine release syndrome (CRS), two of the side effects that most often limit CAR T cells’ use. Seven patients had grade 1 CRS. Most of the toxicity was related to the lymphodepleting conditioning therapy (e.g., bone marrow suppression). 

Six of the 11 patients treated with the highest dose had complete responses and two had partial responses. Four of the eight patients receiving the intermediate dose had partial responses. Three of the six patients receiving the lowest dose had objective responses, one of which was a complete response. 

The data are limited because of the small sample size in the current study, but researchers plan to conduct a future multicenter trial with more patients to confirm the findings.