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Haplo-identical transplants (Haplo-Tx) are an important alternative for patients with hematological malignancies who lack a HLA-identical donor. Seventy-one T-replete Haplo-Tx were performed in 70 high-risk patients at our center; 22/70 (31%) patients with refractory/relapsed leukemia received sequential salvage therapy (SeqTh) with high-dose chemotherapy followed by Haplo-Tx during the chemotherapy-induced neutropenia. Graft-versus-host disease (GVHD) prophylaxis consisted of post-transplant cyclophosphamide (days + 3 and + 4) with tacrolimus and mycophenolic acid. After a median follow-up of 29.2 months, 3-year overall survival (OS) and event-free survival (EFS) were 43.8 and 40.2%, while 3-year cumulative incidences (CIs) of non-relapse mortality (NRM) and relapse (RI) were 27 and 33%. Day 100 and day 400 CI of grade III-IV acute and moderate-severe chronic GVHD were 11 and 15%. Three-year RI was significantly lower in patients in complete remission (CR) versus those not in CR at the time of transplant (21.5 vs. 48%, p = 0.009) and in patients who received PBSC as compared to BM (22 vs. 45%, p = 0.009). In patients treated with SeqTh, 3-year OS was 19%, while 3-year RI and NRM were 52 and 28% at a median follow-up of 50 months. Overall, Haplo-Tx was feasible in heavily pretreated high-risk patients without a suitable HLA-identical donor.

We evaluated a maintenance, post-remission treatment with low-dose chemotherapy plus differentiating agents on poor-prognosis acute myeloid leukemia (AML)/myelodysplastic syndrome (MDS) patients ineligible to allografting. Patients had either age over 60 and/or secondary AML, therapy-related AML, previous relapse, high-risk MDS. Forty-five patients received the maintenance therapy based on two alternated schedules: (a) 6-thioguanine + 13-cis retinoic acid + dihydroxylated vitamin D3 and (b) low-dose cytarabine + 6-mercaptopurine + all-trans retinoic acid + dihydroxylated vitamin D3. We compared their outcome, at a median follow-up of 52 months, to that of a matched population of 49 patients who stopped treatments after consolidation. Maintenance group had a lower relapse incidence (70.3 vs. 86.4 % at 5 years p = 0.007) and a longer disease-free survival (median 21.2 vs. 8.7 months, p = 0.017). The relapse reduction improved overall survival: median 40.4 months (35.9 % at 5 years) for maintenance group vs. 15.8 (14.2 % at 5 years) for controls (p = 0.005). At multivariate Cox analysis, both cytogenetic and maintenance therapies resulted independent outcome predictors for overall survival. Maintenance treatment also reduced minimal residual disease (detected by WT1 and CBFβ-MYH11) in five of eight evaluable patients. The present results suggest that our strategy of maintenance therapy might improve the outcome of poor-risk AML/MDS patients.