ALBERT

Description: HLA incompatibility between the donor and recipient is the most critical factor governing the incidence of rejection and GVHD after conventional allogeneic stem cell transplantation. But the impact of HLA disparity on GVHD and graft rejection after RICT remains to be elucidated. We retrospectively analyzed the outcomes of 437 patients who underwent bone marrow (n=95) or peripheral blood stem cell RICT (n=342). The numbers of patients who received a graft from a HLA-matched (275 from siblings, 11 from family members, and 54 from unrelated donors), one-locus-mismatched, 2- or 3-loci-mismatched donor were 340, 65, and 32, respectively. The HLA-matched group included significantly higher population of patients who received cyclosporine alone for GVHD prophylaxis. The overall cumulative incidence of grade II-IV acute GVHD was 40% for all subjects. It was 38% (95% CI; 33%–43%) in recipients of HLA-matched donors, 43% (95% CI; 31%–54%) in those of one-locus-mismatched donors, and 54% (95% CI; 37%–68%) in those of 2–3-loci-mismatched donors. A Cox regression model adjusted for potential confounders including GVHD prophylaxis demonstrated that 2-3 loci-mismatch was identified as an independent risk factor of grade II-IV acute GVHD (Table). Use of antithymocyte globulin was identified as an independent better protective factor for GVHD (HR;0.66, p=.003). Cumulative incidence of rejection was significantly higher after one-locus mismatch RICT (Table) and the risk tended to increase in relation to an increase of HLA disparity. Malignant disease was identified as an independent prognostic factor for rejection. In patients with hematologic malignancies, overall survival (OS) of recipients of 2–3-loci-mismatched RICT at 1 year (38%, 95%CI; 21%–54%) was significantly worse than that after HLA-matched RICT (65%, 95%CI; 59%–70%). By contrast, there was no statistical difference in the incidence of grade II-IV acute GVHD and OS between HLA-matched RICT and one-locus-mismatched RICT. Multivariate analysis demonstrated 2–3-loci-mismatch (Table) and high-risk disease (HR; 2.3, p=.001) as independent risk factors for OS. Thus, HLA incompatibility between the donor and recipient is an important risk factor for rejection, acute GVHD and overall survival after RICT. Therefore RICT from a one-locus-mismatched donor may represent an effective alternative approach in patients lacking HLA-matched sibling donors. multivariate analysis n acute GVHD Rejection OS HR (95%CI) p HR (95%CI) p HR (95%CI) p match 340 1.0 1.0 1.0 1-mismatch 65 1.4 (0.9–2.2) 0.20 4.5 (1.1–17.9) 0.03 1.0 (0.6–1.6) 0.88 2–3-mismatch 32 2.2 (1.2–4.1) 0.02 7.0 (0.8–64.8) 0.08 3.3 (1.8–6.2)

Description: Background: The optimal therapy for relapsed acute promyelocytic leukemia (APL) after arsenic trioxide (As2O3)-induced remission is unclear. Hematopoietic stem cell transplantation (HSCT) is associated with high morbidity and mortality. Moreover, lasting remission is observed in many patients who are not candidates for HSCT, owing to advanced age or lack of donors, implying that HSCT is not mandatory for durable remission. We evaluated our results of an As2O3-based, non-HSCT regimen for patients with relapsed APL. Materials and methods: Forty-two consecutive patients (18 men, 24 women, median age: 35 years, 12–72) with relapsed (relapse 1, R1=39, R2=3) APL were treated with an-As2O3 based, non-HSCT regimen. The time from last complete remission (CR) was 22 (6–243) months (mo). Initial treatment was As2O3 (10 mg/day) either intravenously (n=16) or orally (n=28) until CR, followed by idarubicin consolidation (6 mg/m2/day x 9). Twenty-five patients received oral-As2O3 maintenance. Post-As2O3 relapses were treated with oral As2O3 + all-trans retinoic acid (ATRA, 45 mg/m2/day) until CR, followed by maintenance (two weeks of ATRA+As2O3 every 2 mo. for 2 years). Post-As2O3/ATRA relapses were treated with oral As2O3+ATRA+ascorbic acid (1g/day) until CR, followed by consolidation/maintenance with the same regimen (2 weeks every 2 mo. for 2 years). Part of the induction and all of the maintenance therapies were given in the outpatient clinic. Results: Forty-one patients (98%) achieved CR after initial As2O3 treatment. One 72-year old man with XYY syndrome, diabetes and mental retardation died of pneumonia. Thirteen relapses occurred at a median of 15 (6–22) mo. As2O3-maintenance significantly decreased further relapses (3/24 with versus 10/17 without As2O3-maintenance, p=0.003). Two relapses died of cerebral APL before further treatment could be administered. Of eleven patients treated with As2O3+ATRA, 10 achieved CR, 8 of whom have remained in remission (median follow-up: 33 mo.). Two post-As2O3/ATRA relapses achieved CR again with As2O3+ATRA+ascorbic acid, and have remained in remission after maintenance treatment with As2O3+ATRA+ascorbic acid. All patients in continuous remission (n=38) were PML/RARa negative on polymerase chain reaction (sensitivity 10−3 to 10−4). Conclusion: Our regimen resulted in a leukemia-free-survival of 89.3%. The results suggest that an oral and mainly outpatient As2O3-based, non-HSCT strategy is efficacious for relapsed APL. In terms of survival, costs, treatment side effects and patient tolerance, the results appear to be comparable to, if not more favorable than, other treatment options based on high dose chemotherapy, graft-versus-leukemia effect, or anti-myeloid antibody therapy.