Prevention of Graft-Versus-Host Disease (GVHD) with Tacrolimus after Allogeneic Grafting for Hematological Malignancies Following Sub-Myeloablative Conditioning.

Severe acute or chronic GVHD following allogeneic hematopoietic stem cell transplantation therapy (HSCT) has a deleterious effect on the successful treatment of hematological malignancies. We have retrospectively studied mycophenolate mofetil (MMF) and tacrolimus (FK) or cyclosporine (CSA) following allogeneic HCST in the prevention of GVDH and the induction of immune tolerance in 93 patients with hematological malignancies using non-myeolablative pre-transplant conditioning. In the current study, there were 35 patients with leukemia, 36 patients with lymphoma, 12 patients with myelodysplastic syndrome or a myeloproliferative disorder and 10 patients with multiple myeloma. There were 63 women and the median age was 42 (15–75) years. Twenty patients had relapsed after previous autologous or allogeneic HSCT and 45 patients were older than 59 years. The remaining patients had co-morbid medical conditions that precluded the use of chemotherapy/radiotherapy dose-intensive pre-conditioning. Conditioning prior to allogeneic HSCT (94 blood stem cell grafts and 1 marrow graft) was fludarabine (90 mg/m2 in three daily doses) and TBI (200cGy) in 86 patients, fludarabine (120 mg/m2 in 4 daily doses) and cyclophosphamide (50mg/kg) in 5 patients, and TBI (200 cGy) only in 4 patients. Forty-three patients received sibling and 50 unrelated grafts. Median follow-up post transplant is 3.0 (0.2–6.1) years. Five (5.3%) patients did not experience sustained hematological chimerism post-transplant. MMF and FK were administered to 33 recipients and MMF and CSA to 60 recipients. The dose and schedule of MMF, CSA and FK have been published (Laport et al. Blood, 2006 and Fay et al. Blood, 1996.) There was no difference in the degree of HLA mismatching between the two groups of patients. Cumulative incidences were used to estimate the incidence of acute and chronic GVHD, all deaths and disease progressions not related to GVHD being considered as the competing events. The Gray test was used to compare cumulative incidences between groups. The unadjusted cumulative incidence of grade III–IV acute GVHD that required oral or systemic corticosteroid therapy, was 54% (95% CI, 40%–68%) in evaluable patients who received CSA in contrast to 38% (95% CI, 18%–58%) in patients who received FK (p-value=0.25). Furthermore, the unadjusted cumulative incidence of extensive chronic GVHD at 1 year was 45% (95% CI, 32%–58%) for CSA versus 34% (95% CI, 14%–54%) for FK (p-value=0.48). Progression-free survival between patients who received FK or CSA at the time of the analysis of this study is similar (p-value=0.6191). The progression-free survival at 1 year was 43% (95% confidence interval [CI], 24%–62%) for CSA versus 43% (95% CI, 31%–55%) for FK. Analyses of the overall morbidity and the incidence of infectious complications between the 2 groups are ongoing. FK combined with MMF may be superior to CSA and MMF in the prevention of GVHD post sub-myeloablative allogeneic HSCT therapy for hematological malignancies and FK may result in improvement of treatment outcome. We believe further study is warranted.