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

Relapse of chronic lymphocytic leukemia (CLL) after allogeneic hematopoietic cell transplantation (HCT) remains a clinical challenge. We studied in a phase II trial whether the addition of peri-transplant rituximab would reduce the relapse risk compared to historical controls (n=157). Patients (n=55) received fludarabine and low-dose total body irradiation combined with rituximab on days −3, +10, +24, +36. Relapse rate at 3 years was significantly lower among rituximab-treated patients versus controls (17% vs. 31%; P=0.04). Overall survival (OS), progression-free survival (PFS) and non-relapse mortality (NRM) were statistically similar: (53% vs. 50%; P=0.8), (44% vs. 42%; P=0.63), and (38% vs. 28%; P=0.2), respectively. In multivariate analysis, rituximab-treatment was associated with lower relapse rates both in the overall cohort [hazard ratio (HR): 0.34, P=0.006] and in patients with high-risk cytogenetics (HR: 0.21, P=0.0003). Patients with no comorbidities who received rituximab-conditioning had an OS rate of 100% and 75% at 1 and 3 years, respectively, with no NRM. Peri-transplant rituximab reduced relapse rates regardless of high-risk cytogenetics. HCT is associated with minimal NRM in patients without comorbidities and is a viable option for patients with high-risk CLL. Clinical trial information: .