Combination of CAR-T cell therapies for relapsed B cell acute lymphoblastic leukemia

This study aimed to investigate if combined CD19 and CD22 chimeric antigen receptor (CAR) T-cell therapies could be used to treat patients with relapsed acute lymphoblastic leukemia (ALL) after transplant.  

This study concluded that this combination improved long-term survival for these patients. 

The prognosis of relapsed ALL after allogeneic (donor) transplantation is poor when treated with standard approaches. CAR-T cell therapies involve taking immune cells called T-cells from the patient and modifying them in the lab to detect and kill cancer cells. They can be engineered to attach to certain proteins on ALL cells such as CD19 or CD22. 

CD19 or CD22 targeted CAR T-cells have shown high complete remission (CR) rates in relapsed/refractory (R/R) ALL. However but it cannot maintain a durable remission in most patients. It was unknown if a combination of CD19 and CD22 CAR-T cells could improve the outcomes for patients with R/R ALL.  

This study involved 21 patients with ALL who had both CD19 and CD22 proteins on leukemia cells. All patients had relapsed after stem cell transplant. Patients were treated with both CD19 and CD22 CAR-T cells within 3 months. Patients were followed up for an average of 19.7 months. 

88.5% of patients were alive after 18 months. 67.5% were alive without complications from ALL after 18 months. 

CAR-T associated graft-versus-host-disease (GVHD) occurred in 23% of patients. GVHD is where the transplanted cells attack the patient.  

This study concluded that combined CD19 and CD22 CAR-T cell therapy can improve long-term survival for patients with post-transplant relapsed ALL. 

This study included a very small number of participants. Most patients were very young, with an average age of 21. The effects of this combination in older patients are not known. Further studies are needed.