Stromal cell-derived factor 1 (SDF1/ CXCL12) and its cognate receptor, CXCR4, play key regulatory roles in CD34 ؉ cell trafficking. We investigated whether AMD3100, a selective CXCR4 antagonist, could mobilize hematopoietic progenitor cells from marrow to peripheral blood in healthy human volunteers. Initially, 10 persons each received a single dose of AMD3100 (80 g/kg subcutaneously), which induced rapid, generalized leukocytosis associated with an increase in peripheral blood CD34 ؉ cells, representing pluripotent hematopoietic progenitors by in vitro colony-forming unit assays, from 3.8 ؎ 0.5/L to 20.7 ؎ 3.5/L at 6 hours. Subsequent dose-response studies showed a maximum increase in circulating CD34 ؉ cells from 2.6 ؎ 0.3/L to 40.4 ؎ 3.4/L at 9 hours after 240 g/kg AMD3100. Serial administration of AMD3100 (80 g/kg/d for 3 days) resulted in consistent, reversible increases in peripheral blood CD34 ؉ cells. AMD3100 was well tolerated and caused only mild, transient toxicity. These findings suggest potential clinical application of AMD3100 for CD34 ؉ cell mobilization and collection for hematopoietic stem cell transplantation.

Context A minimally toxic nonmyeloablative regimen was developed for allogeneic hematopoietic cell transplantation (HCT) to treat patients with advanced hematologic malignancies who are older or have comorbidities. Objective To describe outcomes of patients ≥ 60 years. Design, Setting, and Participants From 1998 to 2008, 372 patients, 60–75 years old were enrolled in prospective clinical HCT trials at 18 collaborating institutions using conditioning with low-dose total body irradiation alone or combined with fludarabine 90 mg/m2 before related (n=184) or unrelated (n=188) donor transplants. Post-grafting immunosuppression included mycophenolate mofetil and a calcineurin inhibitor. Main Outcome Measures Overall and progression-free survivals were estimated by Kaplan-Meier method. Cumulative incidence estimates were calculated for acute and chronic GVHD, toxicities, achievement of full donor chimerism, complete remission, relapse, and non-relapse mortality. Hazard ratios (HR) were estimated from Cox regression models. Results Overall, 5-year cumulative incidences of non-relapse mortality and relapse were 27% (95% CI, 22%–32%) and 41% (95% CI, 36%–46%), respectively, leading to overall and progression-free 5-year survivals of 35% (95% CI, 30%–40%) and 32% (95% CI, 27%–37%), respectively. These outcomes were not statistically significantly different when stratified by age groups. Furthermore, increasing age was not associated with increases in acute or chronic graft-versus-host disease (GVHD) or organ toxicities. In multivariate models, HCT-CI scores of 1–2 [HR, 1.58 (95% CI,1.08–2.31)] and ≥3 [HR, 1.97 (95% CI,1.38–2.80)] were associated with worse survival compared to HCT-CI score of 0 (overall P = 0.003). Similarly, standard relapse risk [HR, 1.67 (95% CI, 1.10–2.54)] and high relapse risk [HR, 2.22 (95% CI, 1.43–3.43)] were associated with worse survival compared to low relapse risk (overall P = 0.0008). Conclusion Among patients aged 60–75 years and treated with nonmyeloablative allogeneic HCT, 5-year overall and progression-free survivals were 35% (95% CI, 30%–40%) and 32% (95% CI, 27%–37%), respectively.

To compare a reduced-intensity conditioning regimen (RIC) with a myeloablative conditioning regimen (MAC) before allogeneic transplantation in patients with myelodysplastic syndrome (MDS) within a randomized trial. Patients and MethodsWithin the European Society of Blood and Marrow Transplantation, we conducted a prospective, multicenter, open-label, randomized phase III trial that compared a busulfan-based RIC with MAC in patients with MDS or secondary acute myeloid leukemia. A total of 129 patients were enrolled from 18 centers. Patients were randomly assigned in a 1:1 ratio and were stratified according to donor, age, and blast count. ResultsEngraftment was comparable between both groups. The CI of acute graft-versus-host disease II to IV was 32.3% after RIC and 37.5% after MAC (P = .35). The CI of chronic graft-versus-host disease was 61.6% after RIC and 64.7% after MAC (P = .76). The CI of nonrelapse mortality after 1 year was 17% (95% CI, 8% to 26%) after RIC and 25% (95% CI, 15% to 36%) after MAC (P = .29). The CI of relapse at 2 years was 17% (95% CI, 8% to 26%) after RIC and 15% (95% CI, 6% to 24%) after MAC (P = .6), which resulted in a 2-year relapse-free survival and overall survival of 62% (95% CI, 50% to 74%) and 76% (95% CI, 66% to 87%), respectively, after RIC, and 58% (95% CI, 46% to 71%) and 63% (95% CI, 51% to 75%), respectively, after MAC (P = .58 and P = .08, respectively). ConclusionThis prospective, randomized trial of the European Society of Blood and Marrow Transplantation provides evidence that RIC resulted in at least a 2-year relapse-free survival and overall survival similar to MAC in patients with MDS or secondary acute myeloid leukemia.