Evaluate the safety, feasibility, and early clinical activity of a CAR T-cell therapy targeting CD19, CD20, and CD22 in patients with relapsed or refractory B-cell malignancies.
Approach:
Study design: First-in-human phase I trial enrolled 18 patients; 16 received treatment. Participants had received a median of three prior treatment regimens.
Therapy and manufacturing: The investigational CAR T cells targeted CD19, CD20, and CD22 and included an OX40 costimulatory domain. Point-of-care production using the CliniMACS Prodigy platform took a median of seven days.
Assessment: Researchers assessed manufacturing feasibility, clinical responses, survival, safety, and T-cell characteristics associated with outcomes.
Key Findings:
Manufacturing succeeded for 16 of 17 patients for whom production was attempted; one attempt failed.
Among treated patients, the overall response rate was 50%, and 38% achieved complete response.
Five of six patients with B-cell non-Hodgkin lymphoma achieved complete remission; four remained in remission beyond one year.
Complete response was 25% in B-cell acute lymphoblastic leukemia. Patients with chronic lymphocytic or prolymphocytic leukemia had stable disease, and neither patient with Richter transformation responded.
One-year overall survival was approximately 61%.
Cytokine release syndrome was grade 1 or 2 in 25% of patients; no severe cases, dose-limiting toxicities, or immune effector cell-associated neurotoxicity syndrome were reported.
Pretreatment T cells from patients whose disease progressed showed increased exhaustion-associated markers PD-1, TIM-3, and TOX. CAR T-cell expansion was not significantly associated with dose or clinical response.
Interpretation:
The phase I findings provide early evidence of feasibility and clinical activity for trispecific CAR T-cell targeting with rapid, point-of-care manufacturing. The authors note that larger studies are needed to validate clinical benefits and further assess T-cell exhaustion as a potential biomarker.
Limitations:
The study included a small, heterogeneous patient population, limiting definitive conclusions.
One manufacturing attempt failed in a heavily pretreated patient.
