Autologous CD7 chimeric antigen receptor T-cell (CAR-T) therapy was safe and effective at inducing remission in pediatric patients with refractory or relapsed (R/R) T-cell acute lymphoblastic leukemia (T-ALL)/lymphoma, according to results of a study presented at the 2022 ASCO Annual Meeting.
R/R T-ALL/lymphoma is associated with poor prognosis. A previous study found that donor-derived CD7 CAR-T cell therapy induced remission in patients, but some patients developed graft-versus-host disease (GVHD).
In this analysis (ClinicalTrials.gov Identifier: NCT04840875), the safety and efficacy of CD7 CAR-T therapy was evaluated in 5 patients with R/R CD7+ T-ALL/lymphoma who had no leukemia cells in peripheral blood. The CD7 CAR-T therapy included an endoplasmic reticulum anchor domain fused to a CD7 binding domain to prevent CD7 expression was given in a 3+3 dose escalation process.
Patients were mean age 3.8 years (range, 1.9 to 13), 3 patients had marrow disease, 1 had central nervous system-3 status, and 1 had mediastinal mass and blasts in pleural fluid.
Three patients developed cytokine release syndrome at a median onset of 5 days (range, 1 to 9).
No GVHD, neurotoxicity, or infection events were observed. Grade 3/4 hematologic toxicity occurred in all patients, recovering to grade 2 by day 30.
At 1-month postinfusion, 4 of the 5 patients had achieved complete remission. One patient underwent stem cell transplantation at 2.9 months postinfusion and had a CD7+ relapse at 1.4 months posttransplantation.
At the last follow-up, all 5 patients had detectable CAR transgene. All 4 responders had a decrease in CD7+ normal T-cells and increased CD7-negative T-cells.
The major limitation of this study was its small sample size.
The study authors concluded that autologous CD7 CAR-T therapy was effective at inducing remission without signs of GHVD in patients with R/R T-ALL/LBL.
Zhao L, Pan J, Tang K, et al. Autologous CD7-targeted CAR T-cell therapy for refractory or relapsed T-cell acute lymphoblastic leukemia/lymphoma. J Clin Oncol. 2022;40(suppl 16; abstr 7035). doi:10.1200/JCO.2022.40.16_suppl.7035