Rituximab-based allogeneic transplant for chronic lymphocytic leukemia with comparison to historical experience

Area of Science:

• Hematology
• Oncology
• Immunotherapy

Background:

• Relapse of chronic lymphocytic leukemia (CLL) post-allogeneic hematopoietic cell transplantation (HCT) is a significant clinical challenge.
• Standard HCT protocols may not adequately address the risk of disease recurrence in CLL patients.

Purpose of the Study:

• To evaluate the efficacy of peri-transplant rituximab in reducing relapse risk following HCT for CLL.
• To compare relapse rates in patients receiving rituximab-augmented HCT versus historical controls.

Main Methods:

• A phase II clinical trial involving 55 patients receiving fludarabine, low-dose total body irradiation, and rituximab.
• Rituximab was administered peri-transplant on days -3, +10, +24, and +36.
• Outcomes were compared against historical controls (n=157).

Main Results:

• The 3-year relapse rate was significantly lower in the rituximab group (17%) compared to controls (31%; P=0.04).
• Multivariate analysis showed rituximab was associated with lower relapse rates (HR: 0.34; P=0.006), particularly in high-risk cytogenetics subgroups (HR: 0.21; P=0.0003).
• Overall survival, progression-free survival, and nonrelapse mortality were statistically similar between groups.

Conclusions:

• Peri-transplant rituximab effectively reduces relapse rates in CLL patients undergoing HCT, irrespective of cytogenetic risk.
• HCT with rituximab conditioning is a viable treatment option for high-risk CLL, demonstrating minimal nonrelapse mortality in patients without comorbidities.