Long-term outcomes for CAR-T cells treatment for relapsed or unresponsive chronic lymphocytic leukemia

This study aimed to investigate the outcomes of anti-CD19 chimeric antigen receptor T cells in patients with relapsed or refractory (unresponsive) chronic lymphocytic leukemia. 

This study concluded that high-dose treatment may be more effective in these patients in the long term.  

Chimeric antigen receptor T (CART) cells are a type of immunotherapy that uses modified T cells to fight cancer. Patients' T cells are collected from blood, modified in a laboratory, and reintroduced to the body.  Anti-CD19 CART cells are one type of these cells. 

It was unknown if anti-CD19 CART cells are effective in patients with relapsed/refractory chronic lymphocytic leukemia (CLL) in the long-term. 

This study involved 42 patients with relapsed or refractory CLL. 38 patients received anti-CD19 CART cells (CART-19). Patients were randomly assigned to receive low dose or high dose CART-19. Patients were followed for an average of 31.5 months.  

At 4 weeks, the complete response (CR; no signs of cancer) rate for all patients was 28%. At 4 weeks, the overall response (OR) rate for all patients was 44%. 

The average overall survival (OS) for all patients was 64 months. There was no significant difference in OS between high- and low-dose groups. Regardless of dose, patients who achieved a CR had better survival when compared to those who did not achieve CR. The average progression-free survival (PFS; survival without cancer worsening) was 40.2 months in patients with a CR compared to 1 month for patients without CR.  

Toxicity was similar in both the high- and low-dose groups. The most common side effects were cytokine release syndrome (CRS; a strong inflammatory response from the body) and low white blood cell counts.

This study concluded that high-dose anti-CD19 CART treatment may be more effective than low-dose in patients with CLL. It was also concluded that regardless of dose, attaining CR after treatment, leads to longer OS and PFS in relapsed patients. 

This study had a small number of participants. Larger studies are needed to confirm these results. Also, this study was partially funded by the Pharma Industry.