Emerging drugs for prevention of graft failure after allogeneic hematopoietic stem cell transplantation

in Expert Opinion on Emerging Drugs (in press)

Introduction: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the treatment of choice for many patients suffering from hematological malignancies, severe hemoglobinopathies, bone marrow ... [more ▼]

Introduction: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the treatment of choice for many patients suffering from hematological malignancies, severe hemoglobinopathies, bone marrow failures or severe primary immunodeficiencies. Graft rejection/failure (GF) is a life-threatening complication following allo-HSCT that is most commonly caused by the reactivity of recipient T cells, natural killer (NK) cells or antibodies against donor grafted hematopoietic cells. The increasing use of allo-HSCT following reduced-intensity conditioning (RIC) and the increasing use of alternative donors (unrelated cord blood and human leukocyte antigen (HLA)-mismatched donor) have resulted in higher frequency of GF. Areas covered: This review describes the pathogenesis and current prevention and treatment of GF as well as agents in development for GF prevention or treatment. Expert opinion: The risk of GF may be reduced in the future by optimizing the conditioning regimens and post-grafting immunosuppression, increasing the number of hematopoietic stem cells (HSCs) and/or immune cells transplanted, optimizing HSC homing and better detecting patients at high risk of GF by searching for pre-transplant donor-specific anti-HLA antibodies in patients given grafts from HLA-mismatched donors, or by closely monitoring donor T- and/or NK-cell chimerism after allo-HSCT following RIC. [less ▲]

A novel mutation in the CUB sequence of matriptase-2 (TMPRSS6) is implicated in iron-resistant iron deficiency anaemia (IRIDA).

in British Journal of Haematology (2013), 160(4), 564-565

Erythropoietin therapy after allogeneic hematopoietic cell transplantation : a prospective randomised trial.

in Belgian Journal of Hematology (2013, January)

Based on the impairment of erythropoietin production after allogeneic hematopoietic cell transplantation (HCT), we previously reported in a phase-2 trial that recombinant human erythropoietin (rhEPO ... [more ▼]

Based on the impairment of erythropoietin production after allogeneic hematopoietic cell transplantation (HCT), we previously reported in a phase-2 trial that recombinant human erythropoietin (rhEPO) therapy was very efficient when started one month after transplantation. We also demonstrated that anemia after nonmyeloabalative (NM) HCT was less sensitive to rhEPO therapy than after conventional allogeneic HCT. This prompted us to confirm these findings in a prospective randomised trial. One hundred and thirty-one patients were randomised (1:1) between no treatment (arm 1) or erythropoietin (Neorecormon) at the dose of 500 U/kg/week (arm 2). Once the target Hb (13g/dL) has been attained, the dose of rhEPO was reduced by half, while it was withheld when Hb was = 14g/dL. Cohort A included 42 patients on day 28 after myeloablative HCT, cohort B 39 patients on day 28 after NMHCT, and cohort C 50 patients on day 0 of NMHCT. Primary endpoints included proportion of complete correctors (i.e. patients reaching Hb = 13g/dL) and median time to achieve Hb correction in each arm. The proportion of complete correctors before day 126 posttransplant was 0% in group 1A vs 52.4% in group 2A, 0% in group 1B vs 69.5% in group 2B and 19.1% in group 1C vs 70.2% in group 2C. Median time to achieve Hb = 13g/dL was not reached in group 1B vs 49 days in group 2B; 363 and 59 days in groups 1A and 1B respectively and 363 and 87 days in groups 3A and 3B respectively (figure 1). Hb evolution in each group is shown in figure 2. Seventyone patients (47/62 in control groups and 24/57 in treated groups, p=0.0003) required red blood cell transfusions. The difference was most pronounced in cohort B. There was no difference in rates of thrombo-embolic events or other complications between the two arms. In conclusion, this is the first trial to demonstrate that EPO therapy hastens erythroid recovery and decreases transfusion requirements when started one month after allogeneic HCT. [less ▲]

Combination of Regulatory T Cells Injection with Rapamycin for Treatment of Chronic Graft-versus-Host Disease

Conference (2013)

Infusion of CliniMACS (Myltenyi Biotec) Enriched Regulatory T Cells Delays Experimental Xenogeneic Graft-versus-Host Disease

in Belgian Journal of Hematology (2013), Abstracts book(Supplement of 28th General Meeting of the Belgian Hematological Society), 15

Kinetics of IL-7 and IL-15 Levels after Allogeneic Peripheral Blood Stem Cell Transplantation following Nonmyeloablative Conditioning

in PLoS ONE (2013), 8(2), 55876

Background: We analysed kinetics of IL-7 and IL-15 levels in 70 patients given peripheral blood stem cells after nonmyeloablative conditioning. Methods: EDTA-anticoagulated plasma and serum samples were ... [more ▼]

Background: We analysed kinetics of IL-7 and IL-15 levels in 70 patients given peripheral blood stem cells after nonmyeloablative conditioning. Methods: EDTA-anticoagulated plasma and serum samples were obtained before conditioning and about once per week after transplantation until day 100. Samples were aliquoted and stored at 280uC within 3 hours after collection until measurement of cytokines. IL-7 and IL-15 levels were measured by ELISAs. Results: Median IL-7 plasma levels remained below 6 pg/L throughout the first 100 days, although IL-7 plasma levels were significantly higher on days 7 (5.1 pg/mL, P = 0.002), 14 (5.2 pg/mL, P,0.001), and 28 (5.1 pg/mL, P = 0.03) (but not thereafter) than before transplantation (median value of 3.8 pg/mL). Median IL-15 serum levels were significantly higher on days 7 (12.5 pg/mL, P,0.001), 14 (10.5 pg/mL, P,0.001), and 28 (6.2 pg/mL, P,0.001) than before transplantation (median value of 2.4 pg/mL). Importantly, IL-7 and IL-15 levels on days 7 or 14 after transplantation did not predict grade II–IV acute GVHD. Conclusions: These data suggest that IL-7 and IL-15 levels remain relatively low after nonmyeloablative transplantation, and that IL-7 and IL-15 levels early after nonmyeloablative transplantation do not predict for acute GVHD. [less ▲]

Allogreffe de cellules souches hématopoïétiques chez le patient âgé : jusqu'à quel âge ?

in Revue Médicale de Liège (2013), 68(1), 38-43

In the last decades, the upper age limit for allogeneic hematopoietic cell transplantation has increased from 50-60 years to 70-75 years of age, in part due to the development of allogeneic ... [more ▼]

In the last decades, the upper age limit for allogeneic hematopoietic cell transplantation has increased from 50-60 years to 70-75 years of age, in part due to the development of allogeneic transplantation following reducedintensity or truly nonmyeloablative conditioning. This review describes challenges and opportunities of allogeneic hematopoietic cell transplantation in the elderly. [less ▲]

Longitudinal Monitoring of Immune Reconstitution after Allogeneic Peripheral Blood Stem Cell Transplantation (PBSCT): Impact of T-Cell Depletion of the Graft

in Biology of Blood & Marrow Transplantation (2012, February), 18(2), 274-275

Rapamycin prevents experimental sclerodermatous chronic graft-versus-host disease in mice

Conference (2012)

Background: The most widely used mice model of chronic graft-versus-host disease (cGvHD) is an MHC-matched bone marrow transplantation model of sclerodermatous cGvHD. A limitation of that model is that ... [more ▼]

Background: The most widely used mice model of chronic graft-versus-host disease (cGvHD) is an MHC-matched bone marrow transplantation model of sclerodermatous cGvHD. A limitation of that model is that mortality is relatively low, making difficult to study the impact of potentially therapeutic compounds. Aims: To develop a more severe model of cGVHD and to assess the impact of Rapamycin administration in that model. Results: Lethally irradiated Balb/C mice were injected with 10x106 bone marrow cells and 70x106 splenocytes from B10.D2 donor mice. Twenty-one days later, all mice developed cGvHD. For the severe model, donor B10.D2 mice were injected with 0.5x106 splenocytes from Balb/C twenty-one days before transplantation. All mice from the severe model (n=8) died a median of 32 days while 3 of 7 mice in the classical model survived beyond day 52. Mean survival was decreased in the severe model compared to the classical model (32 days versus 37 days; p=0.0185). Recipient mice in the severe group experienced higher weight loss, hair loss and skin fi brosis. Numbers of T lymphocytes (231.9 ± 151.4 versus 951 ± 532.8; p=0.0032) and CD4+ T cells (63.25 ± 41.93 versus 135.0 ± 14.39; p=0.0018) per microliter of blood at day 21 were lower in the severe group than in the classical model. Moreover, number of regulatory T cells (Tregs) was decreased in the severe model (1.250 ± 0.8864 versus 8.000 ± 6.753; p=0.0151). We then investigated whether rapamycin administration could prevent GVHD in the severe model. All (n=8) mice treated with PBS (placebo) died a median of 32 days after transplantation, while 6 of 8 mice given 1 mg/kg/day i.p. rapamycin survived beyond day 52 (p=0.0012). Number of Tregs/μl was higher at day 21 in rapamycin-treated mice than in mice given PBS (2.000±1.195 versus 1.250±0.8864; p=0.0796). Moreover, number of naïve CD4+T (10.00±4.192 versus 30.25±5.185; p= 0.0089) and effector memory T cells (EMT) (30.67±3.180 versus 67.33±7.881; p= 0.0125) were higher in rapamycin mice. Finally, proliferation of EMT (assessed by fl ow cytometry using Ki-67) was higher in PBS than in rapamycin mice (45.28%±4.084 versus 31.90%± 2.003; p=0.0474). Conclusion: We have developed a mice model of severe cGVHD. Interestingly, rapamycin prevented death from cGVHD in that model, perhaps through in vivo expansion of Treg. [less ▲]

Bone marrow-derived mesenchymal stromal cells failed to prevent experimental xenogeneic graft-versus-host disease

Poster (2012)