Final results from a decade-long National Cancer Institute study show that CD22-targeted CAR T-cell therapy is a highly effective salvage treatment for children and young adults with B-cell acute lymphoblastic leukemia (B-ALL), especially those who relapsed after CD19 therapies.
Many relapses occur because leukemia cells lose CD19 expression, a problem called antigen escape. Targeting CD22 offers an alternative way to eliminate these resistant cells.
The study followed 78 heavily pretreated patients with a median of six prior therapies. By day 28, 70.1% achieved complete remission, and 83.3% of those had no detectable cancer (MRD-negative). Median overall survival was 13.6 months, with effectiveness observed regardless of disease burden.
Side effects were common but mostly manageable. Cytokine release syndrome occurred in 84.6% of patients, usually mild, while neurotoxicity affected 23.1% and was largely reversible. A rare inflammatory syndrome occurred in 36% of patients.
Researchers concluded that CD22 CAR T-cells are crucial for patients who relapse after CD19 therapy, though many still need a follow-up stem cell transplant to maintain long-term remission.