Thiotepa 10 mg/kg Treatment Regimen Is Superior to Thiotepa 5 mg/kg in TBF Conditioning in Patients Undergoing Allogeneic Stem-Cell Transplantation

Feasibility of thiotepa addition to the fludarabine-busulfan conditioning with tacrolimus/sirolimus as graft vs host disease prophylaxis

In classical reduced-intensity conditioning (RIC) regimens, including the fludarabine and busulphan (BF) combination, sirolimus and tacrolimus (SIR-TAC) as graft vs host disease (GVHD) prophylaxis has shown acceptable results. The outcomes of SIR-TAC in a more intense RIC regimen as Thiotepa-fludarabine-busulfan (TBF) have been hardly investigated. This retrospective study included all consecutive patients receiving an allogeneic hematopoietic stem cell transplantation for myeloid malignancies (January 2009-2017) conditioned with either TBF or BF and receiving SIR-TAC. Patients receiving TBF presented higher non-relapse mortality (31.6 vs 12.3%, p = .01), along with shorter overall survival (51.8% vs 77.8%, p < .01) at 2 years than patients treated with BF. There were no significant differences in the cumulative incidence of grade II-IV acute GVHD or moderate-severe chronic GVHD or relapse between both groups. These results suggest that TBF does not seem to improve the traditional RIC BF regimen, at least when associated with SIR-TAC prophylaxis.

Impact of Adding Antithymocyte Globulin to Posttransplantation Cyclophosphamide in Haploidentical Stem-Cell Transplantation

BACKGROUND

Graft-versus-host disease (GVHD) is a major cause of mortality after allogeneic stem-cell transplantation. Posttransplantation cyclophosphamide (PT/CY) has become standard prophylaxis of GVHD in T-replete haploidentical transplantation. The question is whether adding antithymocyte globulin (ATG) to PT/CY may further reduce the incidence of GVHD compared to PT/CY only.

PATIENTS AND METHODS

We retrospectively studied 268 patients undergoing myeloablative haploidentical transplantation with thiotepa, busulfan, and fludarabine (TBF) conditioning. Sixty-nine patients (26%) received ATG.

RESULTS

In the ATG group, 3% died due to GVHD versus 8% in the no ATG group. The 100-day and 1-year nonrelapse mortality (NRM) was 0% and 19%, respectively, in the whole cohort. On univariate analysis, the 1-year NRM was 8% versus 23% in patients receiving ATG and no ATG, respectively (P = .005). The no ATG group had a higher incidence of acute GVHD at 12 months compared to the ATG group (22% vs. 12%, respectively, P = .029). The ATG group had better overall survival at 12 months compared to the no ATG group (79% vs. 69%, P = .029). On multivariate analysis, adding ATG to PT/CY had no significant impact on any of the outcomes. A low disease risk index was associated with better overall survival and lower NRM, while Hematopoietic Cell Transplantation-Specific Comorbidity Index (HCT-CI) score ≥ 3 was associated with higher NRM.

CONCLUSION

ATG can be safely used as part of the pretransplantation conditioning and does not increase the incidence of relapse or complications after transplantation.

Effect of the Thiotepa Dose in the TBF Conditioning Regimen in Patients Undergoing Allogeneic Stem Cell Transplantation for Acute Myeloid Leukemia in Complete Remission: A Report From the EBMT Acute Leukemia Working Party

BACKGROUND

Allogeneic stem cell transplantation is a potentially curative therapy for patients with acute myeloid leukemia (AML) after achieving complete remission (CR). The aim of this study is to evaluate the optimal dose of thiotepa, administered as part of the thiotepa-busulfan-fludarabine (TBF) conditioning regimen for allogeneic stem cell transplantation in adults with AML in CR.

PATIENTS AND METHODS

In a retrospective multicenter analysis, we identified 240 patients allotransplanted from matched related or unrelated donors or T replete haplo-identical donors. We compared the transplantation outcomes of patients who received 5 mg/kg thiotepa and 2 days of intravenous busulfan at 6.4 mg/kg (T1B2F) versus those who received 10 mg/kg thiotepa with 2 days of intravenous busulfan at 6.4 mg/kg (T2B2F). The median follow-up was 20 months.

RESULTS

On univariate analysis, the incidence of acute graft versus host disease (GVHD) grade II to IV was significantly lower in the T1B2F group (19%) versus 32% in the T2B2F group (P = .029). This result was confirmed on multivariate analysis; acute GVHD was higher for patients receiving T2B2F (hazard ratio, 2.22; P = .024). No significant change in non-relapse mortality, progression-free survival, or overall survival was observed between the 2 groups.

CONCLUSION

T2B2F is associated with a higher incidence of acute GVHD compared with T1B2F. These results suggest that a lower dose-intensity of thiotepa and busulfan in the TBF regimen may yield better results in patients with AML in CR.