HLA Mismatched/Haploidentical Haematopoietic Stem Cell Transplantation for the Treatment of Chronic Myelogenous Leukemia.

Backgroud: Allogeneic marrow transplantation remains the only proven curative therapy for CML, but many patients have no suitably HLA matched related donor. Recently, we developed a new method for HLA-mismatched /haploidentical transplantation without in vitro T cell depletion. Conditioning including antithymocyte globulin followed by un-manipulated HLA-mismatched/haploidentical blood and marrow achieved comparable outcomes to HLA identical sibling transplantation. So good outcomes of HSCT from mismatched family donor for CML patients could be expected.

Methods: 81 consecutive patients received mismatche family donor HSCT for CML were analyzed. There are 40 cases in CP1, 10 cases in CP2 after BC or AP, 14 cases in AP and 17 cases in BC pre-HSCT. Patients received the modified BuCy2 regimen consisting of cytarabine, busulfan, cyclophosphamide, Me-CCNU and ATG. Both of donor G-BM (G-CSF immobilize ) and G-PB were harvested and infused to recipients. All patients were given CsA/MTX and MMF for prophylaxis of GVHD.

Results All patients achieved full donor chimerism. The cumulative incidence of aGVHD is 62.71% (CI 57.3– %−68.2%), grade III–IV is 24.69% (CI 28.7 %−30.7 %). 2 yrs cumulative incidence of cGVHD was 56.48 % (CI 49.6 %–−53.4%). 2 years OS is 71.33%(CI 66%–−76.7%), 2-year LFS were 61.23% (CI 54.66%–−67.8 %). The cumulative incidence of relapse is 17.74% (CI 11.3%–−14.2 %). The incidence of relapse in CML-CP1, CP2, AP and BC group pre-HSCT were 10.8% (CI 2.67%–18.95%), 0%, 9.2% (CI 0.5%–− 17.9%) and 42.71% (28.47%–56.95%%), with P=0.0150. The OS in CML-CP1, CP2, AP and BC group pre-HSCT were 67.66% (59.93%–75.39%), 83.33% (68.12%±098.54%), 77.38% (65.88%±88.90%), 69.68 % (58.32%±81.04 ) with p=0.7876.

Conclusion For patients with CML without an HLA identical sibling donor, haploidentical family members can be an alternative donor for HSCT. In our HSCT protocol, survival of HSCT for CML in advanced stage was no worse than that in stable stage. The optimal time of HSCT for CML patients from MM-family donors need to be further studied.