Comparative Analysis of Matched Related Donor (MRD) and Matched Unrelated Donor (MUD) Hematopoietic Stem Cell Transplantation in Treatment of Patients with Chronic Myeloid Leukemia.

Allogeneic HSCT offers a long term remission for CML patients. We compared results of MRD and MUD HSCT in 82 pts with CML, treated between 1999 and 2005. In MRD group, 61 pts (median age 39, range 8–54 yrs) were conditioned with BuCy2 regimen. 50 pts were in chronic, 7 in acceleration and 4 in 2nd chronic phase. 38 pts received peripheral blood (PB) and 23 bone marrow (BM) cells. Prophylaxis of graft versus host disease (GVHD) consisted of cyclosporin (CsA) and methotrexate (MTX). 21 pts (median age 31, range 11–51 yrs) transplanted from MUD were conditioned with BuCy2 (n=13) or TBI-based regimen (n=8). All MUD patients received thymoglobulin. This group comprised of 14 pts in chronic and 3 with accelerated, 1 in blastic phase and 3 in 2nd chronic phase. 10 pts received PB and 11 BM cells. CsA+MTX was given as GVHD prophylaxis. MUD group differed from MRD group by following factors: younger age (p=0.020), longer time to HSCT (p<0.001), use of imatinib before HSCT (p=0.039), and higher pre-transplant (Gratwohl) risk score (p<0.001). Results: Hematopoietic recovery occurred in all pts in MRD group, and in 95% in MUD group. Probability of overall survival for all pts was OS=0.72±0.05. 42 pts developed acute GVHD >2 grade (26 in MFD and 16 in MUD) and 27 pts extensive chronic GVHD (23 in MFD and 4 in MUD). Mean survival, estimated 5-yrs OS, probabilities of GVHD incidence, relapse and non-relapse mortality (Kaplan-Meier method) with respect to transplantation method, are shown in Table.

Factors predicting negative outcome by multivariate analysis were: acute GVHD≥2 (p=0.0097, HR=1.81, 95%CI=1.12−2.94), and pre-transplant risk score >2 (p=0.0280, HR=1.61, 95%CI=1.06−2.00). MUD-HSCT or use of imatinib before HSCT did not predict for OS. Conclusion: In the era of tyrosine kinase inhibitors, results of MRD− and MUD-HSCT show that HSCT still remains an important therapeutic option for CML patients.