Allogeneic transplantation for high-risk chronic lymphocytic leukemia-a summary of a 16-year experience

In the pathway inhibitor era, the number of allogeneic stem cell transplantation (ASCT) for chronic lymphocytic leukemia (CLL) continues to decrease and this approach should be offered only after careful risk-benefit assessment. Nevertheless, ASCT still remains only curative therapeutic modality for CLL, especially in countries with limited access to novel agents. Thirty patients with CLL at median age of 42 years at diagnosis (range 29-64) underwent ASCT between years 2002 and 2018. Thirteen patients were transplanted in complete remission (CR), ten patients achieved partial response (PR), and seven had stable disease. The median time from diagnosis to transplant was 4 years (range 0.5-12). Twenty-three patients received HLA-matched related donor stem cell grafts, and seven patients received either matched unrelated donor or HLA-mismatched grafts. Reduced intensity conditioning (RIC) and myeloablative regimen (MAC) were used in 24 and 6 patients, respectively. Mortality to day + 100 after transplant was 16% (8% for RIC only). Acute and chronic graft versus host disease (GVHD) developed in 40% and 63% of patients, respectively. Fifteen patients relapsed or progressed after transplant. Thirteen patients (43%) are alive at last follow-up and 10 (77%) remain in clinical CR. Median follow-up for survivors was 6.8 years (range 0.4-15.2). Three-year progression-free and overall survivals were 56% and 60%, respectively. These outcomes were better for patients who received RIC conditioning: 64% and 72%, respectively. CR at transplant was found to have favorable impact on post-allograft survival. RIC should be preferred over MAC. ASCT may remain a valuable option for some CLL patients.