Matched and mismatched unrelated donor transplantation: is the outcome the same as for matched sibling donor transplantation?

Nomogram establishment for short-term survival prediction in ICU patients with aplastic anemia based on the MIMIC-IV database

OBJECTIVE

To establish an efficient nomogram model to predict short-term survival in ICU patients with aplastic anemia (AA).

METHODS

The data of AA patients in the MIMIC-IV database were obtained and randomly assigned to the training set and testing set in a ratio of 7:3. Independent prognosis factors were identified through univariate and multivariate Cox regression analyses. The variance inflation factor was calculated to detect the correlation between variables. A nomogram model was built based on independent prognostic factors and risk scores for factors were generated. Model performance was tested using C-index, receiver operating characteristic (ROC) curve, calibration curve, decision curve analysis (DCA) and Kaplan-Meier curve.

RESULTS

A total of 1,963 AA patients were included. A nomogram model with 7 variables was built, including SAPS II, chronic pulmonary obstructive disease, body temperature, red cell distribution width, saturation of peripheral oxygen, age and mechanical ventilation. The C-indexes in the training set and testing set were 0.642 and 0.643 respectively, indicating certain accuracy of the model. ROC curve showed favorable classification performance of nomogram. The calibration curve reflected that its probabilistic prediction was reliable. DCA revealed good clinical practicability of the model. Moreover, the Kaplan-Meier curve showed that receiving mechanical ventilation could improve the survival status of AA patients in the short term but did not in the later period.

CONCLUSION

The nomogram model of the short-term survival rate of AA patients was built based on clinical characteristics, and early mechanical ventilation could help improve the short-term survival rate of patients.

Haploidentical BMT for severe aplastic anemia with intensive GVHD prophylaxis including posttransplant cyclophosphamide

Severe aplastic anemia (SAA) is a stem cell disorder often treated with bone marrow transplantation (BMT) to reconstitute hematopoiesis. Outcomes of related HLA-haploidentical (haplo) donors after reduced-intensity conditioning with intensive graft-versus-host disease (GVHD) prophylaxis including posttransplantation cyclophosphamide are presented here from 37 SAA, 20 relapsed/refractory (R/R), and 17 treatment-naïve (TN) SAA patients. Median follow-up is 32 months (90% confidence interval [CI], 29-44). The median age was 25 (range, 4-69) years. The median time to neutrophil recovery was 17 days (range, 15-88). Four of 37 patients (11%) experienced graft failure (GF). There was 1 primary GF of 20 patients in the R/R group and 3 of 17 in the TN group at 200 cGy (1 primary, 2 secondary), but none in the 10 patients who received 400 cGy total body irradiation. Two patients with GF succumbed to infection and 2 were rescued with second haplo BMT. The overall survival for all patients is 94% (90% CI, 88-100) at 1 and 2 years. The cumulative incidence of grade II-IV acute GVHD at day 100 is 11%. The cumulative index of chronic GVHD at 2 years is 8%. Similar results were seen in 10 SAA patients who received the identical nonmyeloablative regimen with posttransplant cyclophosphamide but matched donor transplants. Haplo BMT with posttransplant cyclophosphamide represents a potential cure in SAA, with all 20 R/R currently alive, disease-free, and with no evidence of active GVHD. Extending this approach to TN patients was associated with higher GF rates, but an increase in total body irradiation dose to 400 cGy was associated with durable engraftment without greater early toxicity. Nonmyeloablative haplo BMT in TN SAA could lead to a paradigm shift, such that essentially all patients can proceed quickly to safe, curative BMT. These trials were registered at www.cincialtrials.gov as #NCT02224872) and #NCT02833805.

Haploidentical Donor Bone Marrow Transplantation for Severe Aplastic Anemia

Hematopoietic stem cell transplantation (bone marrow transplantation [BMT]) is the only curative treatment of severe aplastic anemia. BMT from an human leukocyte antigen (HLA)-matched sibling donor is the standard of care for young patients; immunosuppressive therapy is used for older patients or those lacking matched sibling donors. Patients with refractory or relapsed disease are increasingly treated with HLA haploidentical BMT. Historically, haploidentical BMT led to high rates of graft rejection and graft-versus-host disease. High-dose post transplant cyclophosphamide, which mitigates the risk of graft-versus-host disease, is a major advance. This article provides an overview of the haploidentical BMT approach in severe aplastic anemia.

Erythropoiesis: insights into pathophysiology and treatments in 2017

Erythropoiesis is a tightly-regulated and complex process originating in the bone marrow from a multipotent stem cell and terminating in a mature, enucleated erythrocyte.Altered red cell production can result from the direct impairment of medullary erythropoiesis, as seen in the thalassemia syndromes, inherited bone marrow failure as well as in the anemia of chronic disease. Alternatively, in disorders such as sickle cell disease (SCD) as well as enzymopathies and membrane defects, medullary erythropoiesis is not, or only minimally, directly impaired. Despite these differences in pathophysiology, therapies have traditionally been non-specific, limited to symptomatic control of anemia via packed red blood cell (pRBC) transfusion, resulting in iron overload and the eventual need for iron chelation or splenectomy to reduce defective red cell destruction. Likewise, in polycythemia vera overproduction of red cells has historically been dealt with by non-specific myelosuppression or phlebotomy. With a deeper understanding of the molecular mechanisms underlying disease pathophysiology, new therapeutic targets have been identified including induction of fetal hemoglobin, interference with aberrant signaling pathways and gene therapy for definitive cure. This review, utilizing some representative disorders of erythropoiesis, will highlight novel therapeutic modalities currently in development for treatment of red cell disorders.

Comparison of Autologous and Unrelated Transplants for Cytogenetically Normal Acute Myelogenous Leukemia

Allogeneic stem cell transplantation (SCT) from an HLA-matched sibling donor (MSD) is a postremission treatment that offers a potential cure for adults with cytogenetically normal (CN) acute myelogenous leukemia (AML) in first complete remission (CR1). The best alternative in the absence of an MSD remains unclear, however. The aim of this study was to retrospectively compare the outcomes of autologous peripheral blood stem cell transplantation (auto-PBSCT; n = 177) and allogeneic bone marrow transplantation (BMT) from an HLA-matched unrelated donor (MUD; n = 173) in adult patients with CN-AML/CR1. Both the multivariate analysis (hazard ratio [HR], 1.18; 95% confidence interval [CI], 0.71 to 1.97; P = .53) and propensity score models (HR, 1.40; 95% CI, 0.80 to 2.43; P = .24) indicated that the leukemia-free survival (LFS) rate of auto-PBSCT was not significantly different from that of MUD-BMT. These results suggest that in the absence of an available MSD, auto-PBSCT remains a viable alternative as postremission therapy in patients with CN-AML/CR1.

Alternative Donor Transplantation with High-Dose Post-Transplantation Cyclophosphamide for Refractory Severe Aplastic Anemia

Severe aplastic anemia (SAA) is a life-threatening hematopoietic stem cell disorder that is treated with bone marrow transplantation (BMT) or immunosuppressive therapy (IST). The management of patients with refractory SAA after IST is a major challenge. Alternative donor BMT is the best chance for cure in refractory SAA, but morbidity and mortality from graft failure and complications of graft-versus-host disease (GVHD) have limited enthusiasm for this approach. Here, we employed post-transplantation high-dose cyclophosphamide in an effort to safely expand the donor pool in 16 consecutive patients with refractory SAA who did not have a matched sibling donor. Between July 2011 and August 2016, 16 patients underwent allogeneic (allo) BMT for refractory SAA from 13 haploidentical donors and 3 unrelated donors. The nonmyeloablative conditioning regimen consisted of antithymocyte globulin, fludarabine, low-dose cyclophosphamide, and total body irradiation. Post-transplantation cyclophosphamide 50 mg/kg/day i.v. on days +3 and +4 was administered for GVHD prophylaxis. Additionally, patients received mycophenolate mofetil on days +5 through 35 and tacrolimus from day +5 through 1 year. The median age of the patients at the time of transplantation was 30 (range, 11 to 69) years. The median time to neutrophil recovery over 1000 × 103/mm3 for 3 consecutive days was 19 (range, 16 to 27) days, to red cell engraftment was 25 (range, 2 to 58) days, and to last platelet transfusion to keep platelets counts over 50 × 103/mm3 was 27.5 (range, 22 to 108) days. Graft failure, primary or secondary, was not seen in any of the patients. All 16 patients are alive, transfusion independent, and without evidence of clonality. The median follow-up is 21 (range, 3 to 64) months. Two patients had grade 1 or 2 skin-only acute GVHD. These same 2 also had mild chronic GVHD of the skin/mouth requiring systemic steroids. One of these GVHD patients was able to come off all IST by 15 months and the other by 17 months. All other patients stopped IST at 1 year. Nonmyeloablative alloBMT using post-transplantation cyclophosphamide allowed for safe expansion of the donor pool to include HLA-haploidentical donors. This approach appears promising in refractory SAA patients. Importantly, engraftment was 100%, pre-existing clonal disease was eradicated, and the risk of GVHD was low.

Graft Transit Time Has No Effect on Outcome of Unrelated Donor Hematopoietic Cell Transplants Performed in Australia and New Zealand: A Study from the Australasian Bone Marrow Transplant Recipient Registry

A previous study found that platelet recovery and mortality were worse in recipients of myeloablative bone marrow transplants where graft transit times were longer than 20 hours. This retrospective study of unrelated myeloablative allogeneic transplantation performed within Australia and New Zealand analyzed transplant outcomes according to graft transit times. Of 233 assessable cases, 76 grafts (33%) were sourced from bone marrow (BM) and 157 (67%) from peripheral blood. Grafts sourced from Australia and New Zealand (47% of total) were associated with a median transit time of 6 hours versus 32 hours for overseas sourced grafts (53% of total). Graft transit temperature was refrigerated in 85%, ambient in 6%, and unknown in 9% of cases, respectively. Graft transit times had no significant effect on neutrophil or platelet engraftment, treatment-related mortality, overall survival, and incidence of acute or chronic graft-versus-host disease. Separate analysis of BM grafts, although of reduced power, also showed no significant difference in either neutrophil or platelet engraftment or survival between short and longer transport times. This study gives reassurance that both peripheral blood stem cell and especially BM grafts subjected to long transit times and transported at refrigerated temperatures may not be associated with adverse recipient outcomes.

Immunosuppressive therapy for transplant-ineligible aplastic anemia patients

Aplastic anemia is a rare life-threatening bone marrow failure that is characterized by bicytopenia or pancytopenia in the peripheral blood and a hypoplastic or aplastic bone marrow. The patients are at risk of infection and hemorrhage due to neutropenia and thrombocytopenia and suffer from symptoms of anemia. The main treatment approaches are allogeneic stem cell transplantation and immunosuppression. Here, we review current standard immunosuppression and the attempts that have been made in the past two decades to improve results: review of recent developments also reveals that sometimes not only the advent of new drugs, good ideas and well-designed clinical trials decide the progress in the field but also marketing considerations of pharmaceutical companies. Aplastic anemia experts unfortunately had to face the situation that efficient drugs were withdrawn simply for marketing considerations. We will discuss the current options and challenges in first-line treatment and management of relapsing and refractory patients with an emphasis on adult patients. Some promising new approaches are currently under investigation in prospective, randomized trials.

Unmanipulated Haploidentical Reduced-Intensity Stem Cell Transplantation Using Fludarabine, Busulfan, Low-Dose Antithymocyte Globulin, and Steroids for Patients in Non-Complete Remission or at High Risk of Relapse: A Prospective Multicenter Phase I/II Study in Japan

This prospective, multicenter phase I/II study of unmanipulated HLA-haploidentical reduced-intensity stem cell transplantation using a low dose of anti-T lymphocyte globulin (ATG) and steroid was conducted in 5 institutions in Japan. Thirty-four patients with hematologic malignancies who were in an advanced stage or at a high risk of relapse at the time of transplantation were enrolled. Among them, 7 patients underwent transplantation as a second transplantation because of relapse after the previous allogeneic stem cell transplantation. The conditioning regimen consisted of fludarabine, busulfan, and ATG (Fresenius, 8 mg/kg), and graft-versus-host disease (GVHD) prophylaxis consisted of tacrolimus and methylprednisolone (1 mg/kg). All patients except 1 (97.1%) achieved donor-type engraftment. Rapid hematopoietic engraftment was achieved, with neutrophils > .5 × 10(9)/L on day 11 and platelets > 20 × 10(9)/L on day 17.5. Treatment was started for ≥grade I GVHD, and the cumulative incidences of acute grade I and grade II to IV GVHD were 27.5% and 30.7%, respectively. The incidence of chronic GVHD (extensive type) was 20%. Fourteen patients (41.2%) had a relapse. The cumulative incidence of transplantation-related mortality at 1 year after transplantation was 26.5%. The survival rate at day 100 was 88.2%. The survival rates at 1 year for patients with complete remission (CR)/chronic phase (n = 8) and non-CR (n = 26) status before transplantation were 62.5% and 42.3%, respectively. In the multivariate analysis, non-CR status before transplantation was the only factor significant prognostic factor of increased relapse (P = .0424), which tended to be associated with a lower survival rate (P = .0524). This transplantation protocol is safe and feasible, if a suitable donor is not available in a timely manner. As the main cause of death was relapse and not GVHD, more intensified conditioning or attenuation of GVHD prophylaxis and/or donor lymphocyte infusion may be desirable for patients with non-CR status.

Controversies and dilemmas in allogeneic transplantation for myelofibrosis

JAK1/2 inhibitors have broadened the therapeutic options in myelofibrosis. Though not curative, they result in a meaningful clinical benefit with relatively fewer side effects. In contrast, allogeneic hematopoietic cell transplantation (HCT) is a potentially curative option, but is associated with significant morbidity and mortality. Hence, an important question is the optimal timing of HCT in the era of JAK inhibitors. Timing of HCT is a crucial decision, and need to be individualized based on the personal preferences and goals of therapy; in addition to patient, disease, and transplant related factors. Risk stratification by the currently established prognostic scoring systems need to be further refined by incorporation of prognostically significant mutations to guide the treatment choices better. Data on use of JAK inhibitors prior to HCT have just started to emerge. We discuss some of the current controversies and dilemmas in transplantation for myelofibrosis based on a few real life scenarios.

Current status of stem cell therapy in China

SUMMARY Stem cells, including embryonic stem cells, somatic stem cells and induced pluripotent stem cells, are a cell population with strong self-renewal capability and multidirectional differentiation potential. Stem cells can differentiate into specific tissues and organs under given conditions and represent an ideal source for the repair and regeneration of tissues and organs. Medical study of stem cell transformation has become an international research focus. This article reviews the status of stem cell therapy in China.