Individualized busulfan dosing improves outcomes compared to fixed-dose administration in pre-transplant minimal residual disease-positive acute myeloid leukemia patients with intermediate-risk undergoing allogeneic stem cell transplantation in CR.

Pre-transplant minimal residual disease (MRD) impacts negatively on post-transplant relapse risk in acute myeloid leukemia (AML). Therapeutic drug monitoring by calculating area under the curve (AUC) was developed to optimize busulfan (Bu) exposure. Here, we compared post-transplant outcomes after individualized versus fixed busulfan dosage in intermediate-risk AML who achieved CR prior to allograft focusing on pre-transplant flow-MRD. Eighty-seven patients (median, 56 years) with intermediate-risk AML and pre-transplant flow-MRD ("different from normal") were included. Thirty-two patients received individualized busulfan; 54 fixed dosages. Individualized dosage was adjusted in 25/32 patients: increased, n = 18/25 (72%); decreased: n = 7/25 (28%). After median follow-up of 27 months, we observed lower 3-year relapses (6%, 2%-19% vs. 35%, 23%-49% p = 0.02), improved 3-year leukemia-free survival (LFS) (78%, 54%-91% vs. 55%, 40%-70% p = 0.009) and - overall survival (OS) (82%, 60%-93% vs. 69%, 54%-81% p = 0.05) after individualized compared to fixed Bu. Non-relapsed mortality (NRM) and acute graft versus host disease (GvHD) were not different. In multivariate analysis, fixed Bu showed unfavorable impact on OS (hazard ratio [HR] 4.6, p = 0.044), LFS (HR 3.6, p = 0.018) and relapses (HR 3.6, p = 0.033). Fixed Bu also had unfavorable impact on LFS (3.6, 1.1-12.6, p = 0.041) in pre-transplant MRD-positive patients. Individualized, AUC-based, busulfan is associated with lower relapses in intermediate-risk AML patients allografted in CR and may overcome pre-transplant MRD-positivity.

Post-Transplantation Day +100 Minimal Residual Disease Detection Rather Than Mixed Chimerism Predicts Relapses after Allogeneic Stem Cell Transplantation for Intermediate-Risk Acute Myelogenous Leukemia Patients Undergoing Transplantation in Complete Remission.

Chimerism and minimal residual disease (MRD) are suggested to be prognostic for post-transplantation relapse in patients with acute myelogenous leukemia (AML). Nevertheless, the predictive value of both approaches in homogeneous populations remains underinvestigated. Here we suggest that MRD may have greater predictive value for relapse than mixed chimerism (MC) in intermediate-risk AML patients. Seventy-nine patients with intermediate-risk AML (40 males; median age, 57 years [range, 19 to 77 years]) were included. MRD detection on day +100 was performed in bone marrow via multiparameter flow cytometry (MFC) and quantitative real-time PCR (qPCR) for patients with an NPM1 mutation. Chimerism analysis was performed in peripheral blood. MC was defined as the persistence of <99.9% of donor alleles. The area under the receiver operating characteristic curve was highest for qPCR-MRD (.93), followed by MFC-MRD (.80) and MC (.65). The highest rate of relapse at 3 years was observed in day +100 qPCR-MRD-positive patients (100%), followed by MFC-MRD-positive patients (55%; P < .001). No patients with MC and without detectable MRD experienced relapse. The median 3-year overall survival (OS) and leukemia-free survival (LFS) for patients with MC without detectable MRD were both 86% (range, 61% to 96%), significantly higher than the values in day +100 MFC-MRD-positive patients (OS, 61% [range, 36% to 84%]; LFS: 30% [range, 11% to 59%]) and with day +100 qPCR-MRD-positive patients (OS: 17% [range, 3% to 56%], P = .001; LFS: 0%, P < .001). In patients with intermediate-risk AML, the qPCR-MRD on day +100 was highly predictive for relapse and long-term survival after allogeneic stem cell transplantation, followed closely by MFC-MRD. In contrast, chimerism status had limited predictive potential. Thus, molecular and flow cytometry MRD monitoring rather than MC in the first several months post-transplantation can identify patients at increased risk of relapse who may benefit from early post-transplantation preemptive intervention.

Post-transplant immune reconstitution after unrelated allogeneic stem cell transplant in patients with acute myeloid leukemia.

We evaluated immune recovery in 67 patients with acute myeloid leukemia (AML) with a median age of 40 years (4-69) following allo-SCT after reduced (n = 35) or myeloablative (n = 32) conditioning. The following lymphocyte populations were determined on days +30, +90, +180, +270, and +365 by flow associated cell sorting: CD3+, CD3+CD4+, CD3+CD8+, CD3+CD4+/CD3+CD8+ ratio, CD3-CD56+, and CD19+ cells. Peripheral blast count >5% was related to lower number of CD3+CD4+ (day +30) and NK cells (day +180; p = 0.02). Intensity of conditioning did not have any significant impact on the kinetics of immune recovery. Patients with normal CD3+CD4+/CD3+CD8+ ratio (day +30) and NK cell count (day +90; p <0.05) experienced better survival than those with decreased parameters. Post-transplant sepsis/severe infections impaired CD3+CD8+ (day +90; p = 0.015) and CD19+ (day +90; p = 0.02) recovery. Relapse in patients following allo-SCT showed an association with decreased numbers of CD19+ (day +270) and NK cells (day +365). Acute GvHD (II-IV) was accompanied by reduced CD19+ and CD3+CD4+ cells. Thus, the evaluation of post-transplant immune reconstitution in patients with AML might improve risk stratification concerning either relapse or TRM and remains to be further explored.

Kinetics of G-CSF and CD34+ cell mobilization after once or twice daily stimulation with rHu granulocyte-stimulating factor (lenograstim) in healthy volunteers: an intraindividual crossover study.

BACKGROUND: G-CSF given as split dose increased the harvested number of CD34+ cells in comparison to a once daily schedule, but the mechanism is poorly understood. STUDY DESIGN AND METHODS: To investigate the schedule dependency of G-CSF in healthy volunteers with respect to CD34+ cell mobilization, the same dose of G-CSF was applied in four healthy volunteers in two different schedules (once daily vs. split doses twice daily) in a crossover design after a washout period of 3 months. CD34+ cell kinetics in serum were determined as well as G-CSF serum kinetics on Days 1 and 4 after stimulation. RESULTS: In all volunteers, the twice daily schedule led to a higher CD34+ cell count after 4 days of G-CSF stimulation (median, 94.5 vs. 47/ microL; p = 0.05). On Days 1 and 4, there was a higher peak serum concentration of G-CSF serum level after the once daily application (15,175 vs. 6,859 pg/mL and 7440 vs. 2388 pg/mL, respectively) than after the twice daily schedule. In contrast, after the once daily application the minimum serum level of G-CSF serum level was lower than after the twice daily schedule (663 vs. 1361 pg/mL and 246 vs. 441 pg/mL, respectively). No difference of area under the curve for G-CSF was observed on Days 1 and 4 after G-CSF stimulation. CONCLUSION: It is suggested that application of G-CSF twice daily leads to a higher CD34+ cell mobilization owing to a higher minimum serum level and therefore to a more continuous serum baseline level resulting in a more efficient CD34+ cell mobilization.

Influence of anti-thymocyte globulin as part of the conditioning regimen on immune reconstitution following matched related bone marrow transplantation.

The aim of this work was to analyze the influence of anti-thymocyte globulin (ATG) as part of the conditioning regimen on immune reconstitution following matched related bone marrow transplantation. The rate and pattern of the recovery of total lymphocytes, natural killer (NK) cells, and several T and B cell subsets were determined in 38 patients for more than 2 years following BMT. We compared two patient groups: the first comprised 19 patients after matched related BMT without ATG prevention for graft-versus-host disease (GVHD) and the second contained 19 patients after matched related BMT with ATG treatment for GVHD prophylaxis. We observed impaired immune reconstitution in the ATG group in comparison with the non-ATG group, indicating a significant influence of ATG on immune recovery for several months after BMT.