Genotypically nonidentical related donors for transplantation of patients with myelodysplastic syndromes: comparison with unrelated donor transplantation and autologous stem cell transplantation

Appropriate pre-transplant strategy for patients with myelodysplastic syndromes receiving allogeneic haematopoietic stem cell transplantation after myeloablative conditioning

Purpose

Appropriate pre-transplant strategies in patients with myelodysplastic syndromes (MDS) remain challenging. We sought to assess the effect of different pre-transplant therapies and transplantation interval times on patient prognosis.

Methods

We retrospectively analysed clinical data for 371 consecutive MDS patients after myeloablative transplantation between 2007 and 2019.

Results

The median age of the patients was 38 years (range, 12-64 years). A total of 114 patients (31%) received supportive care (SC), 108 (29%) hypomethylating agents (HMAs), and 149 (40%) chemotherapy-based therapy before transplantation. In patients who received HMA or SC, there was no significant difference in overall survival (OS; P=0.151) or relapse-free survival (RFS; P=0.330), except that HMA-treated patients had a lower rate of non-relapse mortality (5-year NRM: 18% vs. 32%, P=0.035). However, compared with patients who received HMA, those who received chemotherapy-based therapy had a lower 5-year OS rate (56% vs. 69%, P=0.020) and a slightly higher 5-year NRM rate (28% vs. 18%, P=0.067). Compared to the delayed transplant group (transplant interval ≥6 months), the early transplant group (transplant interval <6 months) had a superior 5-year OS (66% vs. 51%, P=0.001) and a lower 5-year cumulative incidence of NRM (22% vs. 36%, P=0.001).

Conclusion

The findings of the study indicate that receiving an appropriate pre-transplant strategy (SC/HMA + <6 months) significantly improves OS and decreases NRM in MDS patients after myeloablative transplantation.

Haploidentical transplant for myelodysplastic syndrome: registry-based comparison with identical sibling transplant

Encouraging results from a small sample of patients with myelodysplastic syndrome (MDS) undergoing haploidentical donor (HID) hematopoietic stem cell transplantation (HSCT) must be extended. Furthermore, an algorithm derived from a comparison of the outcomes of HID and identical-sibling donor (ISD) HSCT must be established. Therefore, the outcomes of 454 MDS patients who underwent HSCT from HIDs (n=226) or ISDs (n=228) between 2003 and 2013 that were reported to the Chinese Bone Marrow Transplantation Registry were analyzed. Among the 3/6 HID (n=136), 4-5/6 HID (n=90) and ISD patient groups, the 4-year adjusted cumulative incidences of non-relapse mortality were 34, 29 and 16%, respectively (overall P=0.004), and of relapse were 6, 7 and 10%, respectively (overall P=0.36). The 4-year adjusted probabilities of overall survival were 58, 63 and 73%, respectively (overall P=0.07), and of relapse-free-survival were 58, 63 and 71%, respectively (overall P=0.14); pairwise comparison showed that the difference was only statistically significant in the 3/6 HID vs ISD pair. The data suggest that ISDs remain the best donor source for MDS patients while HIDs (perhaps 4-5/6 HID in particular) could be a valid alternative when an ISD is not available; human leukocyte antigen disparity had no effect on survival among the HID patients.

Allogeneic hematopoietic stem cell transplantation for myelodysplastic syndromes

Allogeneic stem cell transplantation (SCT) is the only treatment with curative potential for myelodysplastic syndrome (MDS). The availability of SCT has been expanded with the introduction of reduced intensity conditioning for older patients and the use of alternative donors. Treatment-related mortality and relapse have remained major barriers to uniform success and there is a significant need for innovative approaches to improve these outcomes. Encouraging results have been reported for patients who lack a human leukocyte antigen-identical donor with the use of cord blood and haploidentical donors. Improved approaches for patient selection and optimization of the timing of SCT are needed. New prognostic classification schemas identify risk groups for disease outcomes and facilitate decisions with regard to SCT. Patients with intermediate-2 and high-risk disease and those with therapy-related MDS have a poor prognosis with alternative therapies; improved results have been reported with hematopoietic transplantation. The optimum timing for SCT is controversial in the era of hypomethylating agents. Initial conservative management is indicated for patients with low-risk disease. Hematopoietic transplantation remains the only curative treatment for patients with MDS and should be used before patients overtly progress to advanced disease. Failure to respond to hypomethylating agents does not adversely affect the outcome of SCT; these patients might achieve durable remissions with hematopoietic transplantation. Refined prognostic markers are needed to identify poor prognosis patients to guide patient selection for SCT, and novel transplantation approaches are required to reduce the risk of disease relapse and complications of the procedure.

Diagnosis and treatment of primary myelodysplastic syndromes in adults: recommendations from the European LeukemiaNet

Within the myelodysplastic syndrome (MDS) work package of the European LeukemiaNet, an Expert Panel was selected according to the framework elements of the National Institutes of Health Consensus Development Program. A systematic review of the literature was performed that included indexed original papers, indexed reviews and educational papers, and abstracts of conference proceedings. Guidelines were developed on the basis of a list of patient- and therapy-oriented questions, and recommendations were formulated and ranked according to the supporting level of evidence. MDSs should be classified according to the 2008 World Health Organization criteria. An accurate risk assessment requires the evaluation of not only disease-related factors but also of those related to extrahematologic comorbidity. The assessment of individual risk enables the identification of fit patients with a poor prognosis who are candidates for up-front intensive treatments, primarily allogeneic stem cell transplantation. A high proportion of MDS patients are not eligible for potentially curative treatment because of advanced age and/or clinically relevant comorbidities and poor performance status. In these patients, the therapeutic intervention is aimed at preventing cytopenia-related morbidity and preserving quality of life. A number of new agents are being developed for which the available evidence is not sufficient to recommend routine use. The inclusion of patients into prospective clinical trials is strongly recommended.

Review of stem-cell transplantation for myelodysplastic syndromes in older patients in the context of the Decision Memo for Allogeneic Hematopoietic Stem Cell Transplantation for Myelodysplastic Syndrome emanating from the Centers for Medicare and Medicaid Services

Myelodysplastic syndromes (MDS) comprise a heterogeneous group of clonal hematopoietic stem-cell disorders that result in varying degrees of cytopenia and risk of transformation into acute leukemia. Allogeneic stem-cell transplantation (SCT) is the only known cure for this disease. The treatment is routinely used for younger patients, but only a minority of patients older than the age of 60 undergo this procedure. The overall MDS incidence is 3.3 per 100,000, but the incidence in patients older than age 70 is between 15 and 50 per 100,000. The median age at presentation is 76 years. Medicare-age patients 65 or older represent 80% of the total population receiving an MDS diagnosis. In the United States, one of the obstacles to SCT for older patients with MDS has been lack of third party reimbursement. On August 4, 2010, the Centers for Medicare and Medicaid Services released their Decision Memo for Allogeneic Hematopoietic Stem Cell Transplantation (HSCT) for Myelodysplastic Syndrome. This memo states: "Allogeneic HSCT for MDS is covered by Medicare only for beneficiaries with MDS participating in an approved clinical study that meets the criteria below…. " In this review, we will summarize what is known regarding the role of allogeneic SCT in older patients as well as other elements that should be included within clinical trials that can provide the evidence necessary to demonstrate that allogeneic SCT should be a covered benefit for Medicare beneficiaries.

Analysis of risk factors influencing outcome in children with myelodysplastic syndrome after unrelated cord blood transplantation

We describe 70 children with myelodysplastic syndrome (MDS) (refractory cytopenia (n=31) and refractory anemia with excess blasts (n=30) or blasts in transformation (n=9)) who received umbilical cord blood (UCB) transplantation with a single UCB unit and a myeloablative conditioning regimen. Approximately 20% of children had secondary MDS. Median age at transplantation was 7 years and the median follow-up was 3 years. The day-60 probability of neutrophil recovery was 76%; recovery was faster after transplantation of matched or 1-locus mismatched UCB, irradiation-containing conditioning regimen, cell dose >6 × 10(7)/kg and monosomy 7. Risks of treatment failure (recurrent disease or death) were lower in patients with monosomy 7 and transplantations after 2001. The 3-year disease-free survival (DFS) was 50% for transplantations after 2001 compared with 27% for the earlier period (P=0.018). Transplantations after 2001 occurred within 6 months after diagnosis and used UCB units with higher cell dose. DFS was highest in patients with monosomy 7 (61%) compared with other karyotypes (30%), P=0.017. These data suggest that transplantation of mismatched UCB graft is an acceptable alternative for children without a matched sibling or suitably matched unrelated adult donor.

Unrelated cord blood transplantation after myeloablative conditioning in adults with advanced myelodysplastic syndromes

We analyzed the disease-specific outcomes of adult patients with advanced myelodysplastic syndrome (MDS) treated with cord blood transplantation (CBT) after myeloablative conditioning. Between August 1998 and June 2009, 33 adult patients with advanced MDS were treated with unrelated CBT. The diagnoses at transplantation included refractory anemia with excess blasts (n=7) and MDS-related secondary AML (sAML) (n=26). All patients received four fractionated 12 Gy TBI and chemotherapy as myeloablative conditioning. The median age was 42 years, the median weight was 55 kg and the median number of cryopreserved nucleated cells was 2.51 × 10(7) cells per kg. The cumulative incidence of neutrophil recovery at day 50 was 91%. Neutrophil recovery was significantly faster in sAML patients (P=0.04). The cumulative incidence of plt recovery at day 200 was 88%. Plt recovery was significantly faster in CMV seronegative patients (P<0.001). The cumulative incidence of grade II-IV acute GVHD (aGVHD) and extensive-type chronic GVHD was 67 and 34%, respectively. Degree of HLA mismatch had a significant impact on the incidence of grade II-IV aGVHD (P=0.021). TRM and relapse at 5-years was 14 and 16%, respectively. The probability of EFS at 5 years was 70%. No factor was associated with TRM, relapse and EFS. These results suggest that adult advanced MDS patients without suitable related or unrelated BM donors should be considered as candidates for CBT.

HLA-mismatched hematopoietic SCT without in vitro T-cell depletion for myelodysplastic syndrome

Allogeneic hematopoietic SCT (HSCT) is currently the only curative treatment for myelodysplastic syndrome (MDS). However, many patients cannot find an HLA-matched donor. We have developed a new protocol for HLA-mismatched (including haploidentical) HSCT using G-CSF-primed BM plus G-CSF-mobilized PBSCs without in vitro T-cell depletion. A total of 36 patients diagnosed with high-risk MDS (RAEB (refractory anemia with excess blasts) or RAEBt (RAEB in transformation)) underwent transplantation from HLA-mismatched family donors. All patients achieved sustained myeloid engraftment. The cumulative incidence of grades II-IV acute GVHD (aGVHD) was 60% and that of grades III and IV aGVHD was 15%. The 2-year cumulative incidence of chronic GVHD was 56%. After a median follow-up of 17 months, 4 patients had relapsed and died and 25 patients were still alive. The 2-year probability of leukemia-free survival (LFS) was 65%. Patients transplanted within 7 months of diagnosis had better LFS (89 vs 43% ). Severe aGVHD decreased the LFS significantly by increasing non-relapse mortality (NRM). This study confirms that HLA-mismatched HSCT is a treatment option for MDS. Patients with high-risk MDS benefit from receiving HSCT early in the course of the disease.

The efficacy of unrelated cord blood transplantation for adult myelodysplastic syndrome

Although allogeneic stem cell transplantation from a human leukocyte antigen (HLA)-identical related donor offers a potential cure for patients with myelodysplastic syndrome (MDS), a suitably matched related donor is unavailable for approximately two thirds of patients. Recently, umbilical cord blood from unrelated donors have been used as an alternative stem cell source for adult patients with MDS. Here, we updated the results of unrelated cord blood transplantation (CBT) after myeloablative conditioning for 22 adult patients with MDS. Diagnosis at transplantation included refractory anemia (RA) (n = 3), refractory anemia with excess blasts (RAEB) (n = 2), RAEB-t (n = 2), and MDS-related secondary acute myeloid leukemia (AML) (n = 15). All patients were treated with total body irradiation (12 Gy), cytosine arabinoside (Ara-C) and cyclophosphamide followed by unrelated HLA-mismatched CBT. The median age was 40 years (range, 19 - 51 years), the median weight was 54.5 kg (range, 43 - 75 kg), and the median number of cryopreserved nucleated cells was 2.43 x 10(7)/kg (range, 1.82 - 4.10 x 10(7)/kg). Twenty one patients had myeloid reconstitution and the median time to more than 0.5 x 10(9)/l absolute neutrophil count was 22.5 days. A self-sustained platelet count more than 50 x 10(9)/l was achieved in 19 patients at a median time of 49 days. Acute GVHD above grade II occurred in seven of 21 evaluable patients and chronic GVHD in 16 of 19 evaluable patients. Among 16 chronic GVHD patients, in eight patients the disease was extensive. Seventeen patients are alive and free of disease at between 371 and 2562 days after transplantation. With a median follow-up of 1505 days, the probability of disease-free survival at 4 years was 76.0%. These results suggest that adult MDS patients without suitable related or unrelated bone marrow donors should be considered as candidates for CBT.

The role of cytotoxic therapy with hematopoietic stem cell transplantation in the therapy of myelodysplastic syndromes: an evidence-based review

Clinical research examining the role of hematopoietic stem cell transplantation (SCT) in the therapy of myelodysplastic syndromes (MDS) in adults is presented and critically evaluated in this systematic evidence-based review. Specific criteria were used for searching the published literature and for grading the quality and strength of the evidence and the strength of the treatment recommendations. Treatment recommendations based on the evidence are presented in Table 3, and were reached unanimously by a panel of MDS experts. The identified priority areas of needed future research in MDS include: (1) the benefit of using alternative donor sources (eg, cord blood; haploidentical family donors) for patients without matched sibling or unrelated donors; (2) the role and appropriate timing of allogeneic SCT in combination with hypomethylating and immunomodulatory treatment regimens; (3) randomized trials comparing the safety and efficacy of various novel agents for treating MDS; and (4) the influence of the various MDS treatment modalities on patient-reported quality-of-life outcomes.

A retrospective comparison of autologous and unrelated donor hematopoietic cell transplantation in myelodysplastic syndrome and secondary acute myeloid leukemia: a report on behalf of the Chronic Leukemia Working Party of the European Group for Blood and Marrow Transplantation (EBMT)

Hematopoietic cell transplantation (HCT) is an effective treatment for myelodysplasia (MDS) and secondary acute myeloid leukemia (sAML). In this study, outcome of 593 patients with MDS/sAML after autologous and allogeneic HCT from a matched unrelated donor (MUD) were compared. A total of 167 (28%) patients received HCT from MUD without prior chemotherapy (MUD-U). The rest received HCT in first complete remission (CR1) (Autologous (Auto-CR1), n=290 (49%), HCT from MUD (MUD-CR1), n=136 (23%)). Survival at 3 years was best in MUD-CR1 (50%) compared to Auto-CR1 (41%) and MUD-U (40%) (P=0.01). Similarly, disease-free survival was 44% for MUD-CR1 compared to Auto-CR1 (28%) and MUD-U (34%) (P=0.03). Treatment-related mortality was 17% in Auto-CR1 compared to MUD-CR1 (38%) and MUD-U (49%) (P<0.001). Relapse for Auto-CR1 was 62% compared to 24 and 30% for MUD-CR1 and MUD-U, respectively (P<0.001). Outcome was best for patients with low tumor burden transplanted 6-12 months after diagnosis. Factors influencing outcome at 3 years were mainly significant in the first 6 months. Only, relapse after autologous HCT remained constant over time. Outcomes after allogeneic HCT in patients of 20-40 and >40 years were similar. Autologous and Allogeneic HCT from MUD offer the possibility of long-term survival to patients with MDS/sAML.

Hemopoietic cell transplantation as curative therapy of myelodysplastic syndromes and myeloproliferative disorders

Hemopoietic cell transplantation (HCT) is presently the only therapy with curative potential for myelodysplastic syndromes (MDS) and myeloproliferative disorders (MPD). Among patients with less advanced MDS, 3-year survival figures of 65-80% are achieved with human leukocyte antigen (HLA)-identical related and unrelated donors. The probability of relapse is less than 5%. Among patients with advanced MDS (> or = 5% marrow blasts), about 35-50% of patients transplanted from related donors, and 25-40% transplanted from unrelated donors are surviving in remission beyond 3 years. The incidence of post-transplant relapse is 10-35%. Criteria of the International Prognostic Scoring System (IPSS) predict relapse and survival following HCT. In patients with myelofibrosis, allogeneic transplantation is successful in 50-80%, if performed during the fibrosis stage. The success rate declines to 25-40%, if the transplant is performed after leukemic transformation has occurred. About 40% of patients with chronic myelomonocytic leukemia survive in remission after transplantation. Results obtained with low/reduced-intensity conditioning regimens are encouraging because of a low incidence of early mortality. However, retrospective analyses comparing low intensity and conventional conditioning regimens have yielded inconclusive results regarding long-term outcome. Co-morbid conditions present at the time of transplantation have a major negative effect on transplant outcome. Controlled prospective trials are needed.

Management of patients with higher risk myelodysplastic syndromes

Higher risk myelodysplastic syndromes (MDS) include patients in the Intermediate-2 and high-risk categories of the International Prognostic Scoring System, as well as patients with MDS secondary to radiation or chemical exposure. Ideally, the goal of therapy is to alter the natural history of disease in these patients to achieve cure or durable remission. High-intensity chemotherapy can achieve moderate rates of complete remission, however, durability of remission and overall survival tend to be short. Hematopoietic stem cell transplantation (HSCT) offers the possibility of cure, with long-term disease-free survival inversely related to age. Patients who are elderly or have poor functional status are candidates for reduced intensity HSCT, although this is still an experimental modality. Azacitidine is a hypomethylating agent that is a reasonable option for many patients ineligible for high-intensity therapies. Other therapies, such as immunomodulatory agents, arsenic trioxide, and farnesyl transferase inhibitors have thus far shown limited usefulness in higher risk MDS. This paper reviews the various therapeutic options for higher risk MDS, providing rationale for specific management approaches for these patients.

Unrelated cord blood transplantation after myeloablative conditioning for adult patients with refractory anemia

We report the results of unrelated cord blood transplantation (CBT) after myeloablative conditioning in 3 patients with myelodysplastic syndrome-refractory anemia (MDS-RA). All patients were treated with total body irradiation, cytosine arabinoside (Ara-C), and cyclophosphamide, followed by unrelated HLA-mismatched CBT. Granulocyte colony-stimulating factor was infused continuously, starting 12 hours before Ara-C therapy and continuing until the end of Ara-C therapy. All patients received standard cyclosporine and methotrexate therapy as graft-versus-host disease prophylaxis. All patients had myeloid reconstitution, and the times to reach an absolute neutrophil count >0.5 x 10(9)/L were 23, 20, and 26 days. All patients showed full donor chimerism at the time of the first bone marrow examination (on day +42, +43, and +62) after CBT. All patients are alive and free of disease at between 17 and 39 months after CBT. These results suggest that adult MDS-RA patients without suitable related or unrelated bone marrow donors should be considered as candidates for CBT.

Allogeneic hematopoietic cell transplantation from alternative donors in children with myelodysplastic syndrome: is that an alternative?

Allogeneic hematopoietic cell transplantation (HCT) in children with myelodysplastic syndrome (MDS) remains a challenge due to the toxic conditioning regimens administered to minimize the risk of relapse in the HLA-matched or of graft rejection in the HLA-mismatched settings. In the absence of matched sibling donors, alternative donors such as unrelated and/or partially matched family sources remain risky, yet the only available, options. Herein we report the results of HCT from alternative donors in 14 children with different subtypes of MDS (juvenile myelomonocytic leukemia [JMML] n = 9; myelodysplastic syndrome [MDS] refractory anemia n = 3; MDS refractory anemia with excess of blasts in transformation n = 2) transplanted at our institution. The median time from diagnosis to HCT was 9 months (range 4 to 90 months). The variety of HCT types included: unrelated peripheral blood progenitor cell transplantation (PBPCT) (n = 2), partially matched family donor T-cell-repleted BMT/PBPCT (n = 6), and haploidentical T-cell-depleted PBPCT (n = 6). Five of 14 patients remain alive at 7 to 37 months posttransplant (including two patients after partially matched family donor BMT, two patients after haploidentical T-cell-depleted-PBPCT, and one after unrelated-PBPCT, respectively). The major complications were: primary graft failure in the haploidentical T-cell-depleted-setting or graft-versus-host disease (GvHD) in T-cell-repleted partially matched family or unrelated settings, respectively. Despite the high transplant-related mortality rate in this series, allogeneic HCT from alternative donors remains an interesting solution for children with MDS who lack matched sibling donors. Due to improved immune reconstitution, despite an increased risk of GvHD, T-cell-repleted transplants from single HLA-mismatched family donors remain a valuable option for children without matched donors. Splenectomy prior to HCT may positively affect the posttransplant course in patients with overt splenomegaly for example those afflicted with JMML.

Effective donor lymphohematopoietic reconstitution after haploidentical CD34+-selected hematopoietic stem cell transplantation in children with refractory severe aplastic anemia

Peritransplant toxicity and a delay in effective immune reconstitution have limited the utility of alternate donor transplantation for children with refractory severe aplastic anemia. We have assessed the effectiveness of infusing large numbers of highly purified haploidentical CD34+ cells after immunoablative conditioning in three patients who had failed intensive immunosuppression, lacked unrelated donors, and had active or recent serious infections. One patient rejected the first infusion, but engrafted after a second infusion from the same donor. This patient died 4 months after hematopoietic stem cell transplantation with no evidence of lymphoid reconstitution. Two patients experienced mixed chimerism requiring treatment with antibodies and/or donor lymphocyte infusion. Both currently survive more than 1 year after transplantation with normal blood counts, 100% donor engraftment, effective lymphoid reconstitution, and no chronic graft-versus-host disease. We observed functional thymopoiesis as measured by lymphocyte immunophenotyping, T cell receptor excision circles and T cell receptor Vbeta spectratyping complexity analysis. Further study is required to validate the initial promise of these preliminary observations.

Hematopoietic cell transplantation for adult patients with myelodysplastic syndromes and myeloproliferative disorders

Hematopoietic cell transplantation (HCT) is currently the only treatment with curative potential for myelodysplastic syndromes (MDS) and myeloproliferative disorders (MPD). Among patients with less advanced MDS, 3-year survival rates of 65% to 75% are achieved with HLA-identical related and unrelated donors. The probability of relapse is less than 5%. Among patients with advanced MDS (> or = 5% marrow blasts), about 35% to 45% who receive transplants from related donors and 25% to 30% who receive transplants from unrelated donors are in remission beyond 3 years. The incidence of posttransplantation relapse is 10% to 35%. Criteria of the International Prognostic Scoring System (originally developed for nontransplant patients) also predict relapse and survival after HCT. Transplantation is successful in 50% to 80% of patients with MPD if performed before leukemic transformation. Depending on the individual risk profile, a considerable number of patients with MDS or MPD are cured by allogeneic HCT. However, HCT should be performed before disease progression. Outcome of patients with treatment-related MDS or with relapse after transplantation remains poor. At present, no definite conclusions can be made with regard to reduced-intensity transplantation regimens.

Unrelated cord blood transplantation for adult patients with advanced myelodysplastic syndrome

We report the results of unrelated cord blood transplantation (CBT) for 13 adult patients with advanced myelodysplastic syndrome (MDS). The median age was 40 years, the median weight was 51 kg, and the median number of infused nucleated cells was 2.43 x 107/kg. Twelve patients had myeloid reconstitution, and the median time to more than 0.5 x 109/L (5 x 108/L) absolute neutrophil count was 22.5 days. A self-sustained platelet count more than 50 x 109/L was achieved in 11 patients at a median time of 49 days. Acute graft versus host disease (GVHD) occurred in 9 of 12 evaluable patients and chronic GVHD in 8 of 11 evaluable patients. Ten patients are alive and free of disease at between 171 and 1558 days after transplantation. The probability of disease-free survival at 2 years was 76.2%. These results suggest that adult advanced MDS patients without suitable related or unrelated bone marrow donors should be considered as candidates for CBT.

Conditioning with targeted busulfan and cyclophosphamide for hemopoietic stem cell transplantation from related and unrelated donors in patients with myelodysplastic syndrome

A total of 109 patients (aged 6-66 years; median, 46 years) with myelodysplastic syndrome (MDS) were treated with busulfan (BU) targeted to plasma concentrations of 800 to 900 ng/mL plus cyclophosphamide (CY), 2 x 60 mg/kg, and hemopoietic stem cell (HSC) transplantation from related (n = 45) or unrelated donors (n = 64). At the time of transplantation, 69 patients had less than 5% myeloblasts in the marrow, and 40 patients had more advanced disease. All but 2 evaluable patients had engraftment. The Kaplan-Meier estimates of 3-year relapse-free survival (RFS) were 56% for related and 59% for unrelated recipients. The cumulative incidences of relapse were 16% for related and 11% for unrelated recipients. Nonrelapse mortality (NRM) at 100 days (3 years) was 12% (28%) for related and 13% (30%) for unrelated recipients. The only factor significant for RFS was the etiology of MDS (de novo better than treatment related; P =.03). Factors significantly correlated with relapse were advanced French-American-British classification (P =.002) and International Prognostic Scoring System score (P =.009), poor-risk cytogenetics (P =.03), and treatment-related etiology (P =.03). None of the factors examined was statistically significant for NRM. Patient age and donor type had no significant impact on outcome. RFS tended to be superior in patients receiving transplants with peripheral blood rather than marrow stem cells. Thus, a targeted BUCY regimen provided effective transplant conditioning for patients with MDS receiving transplants from HLA-identical siblings or alternative donors. Although there was still considerable nonrelapse morbidity and mortality, the present regimen was used successfully even in patients older than 60 years of age.

Stem cell transplantation for leukemias following myelodysplastic syndromes or secondary to cytotoxic therapy

Two main forms of therapy-related myelodysplastic syndrome and acute myeloid leukemia (t-MDS/AML) have been recognized. The most frequent type, occurring after treatment with alkylating agents, is characterized by abnormalities of chromosomes 5 and/or 7 and t-MDS/AML following treatment with topoisomerase II inhibitors and is associated with molecular aberrations of MLL (11q23) and AML-1 (21q22). Individuals with certain polymorphisms associated with impaired detoxification of cytotoxic agents have an increased risk of developing MDS or AML after treatment of unrelated cancers. Multidrug chemotherapy is less effective for patients with MDS, or AML following MDS, or t-MDS/AML when compared with primary AML, and results in lower complete remission (CR) rates and lower long-term survival. Patients with good risk cytogenetic features, such as t(15; 17), t(8; 21) and inversion 16 are an exception as their treatment outcome is comparable with primary AML patients. Patients who attain a polyclonal and/or a cytogenetic CR may be candidates for autologous stem cell transplantation. For the remaining patients, the only curative option is allogeneic stem cell transplantation with stem cells from a histocompatible sibling or an alternative donor. Reduced intensity conditioning regimens may be considered for patients older than 50 years or patients with comorbidities. The advice is to treat patients early after diagnosis and preferably before progression as these patients have the highest chance of a favorable outcome.