Conventional versus reduced-intensity conditioning regimen for allogeneic stem cell transplantation in patients with hematological malignancies

BACKGROUND: Allogeneic hematopoietic stem cell transplantation (HSCT) from human leukocyte antigen (HLA)-compatible sibling donors is a potential curative treatment for hematological and non-hematological malignancies. Nevertheless, high mortality rates may be associated with this therapy, especially in older patients, those with other comorbidities or who receive a second HSCT. PATIENTS AND METHODS: We analyzed the factors associated with transplant-related mortality (TRM) and overall survival in 157 consecutive adult patients (104 males and 53 females) who received a HSCT [29 bone marrow (BM) transplantation and 128 peripheral blood (PB) transplantation] from a HLA-identical sibling between January 1995 and March 2002 in our institution. One hundred patients received a standard conditioning prior to HSCT (STAND) and 57 patients received a reduced-intensity conditioning (RIC) HSCT. Fifty-eight patients were in an early phase at transplant and 99 in a non-early phase. Median age was 46 yr (16-66), and 90 patients (57%) were >45 yr of age. RESULTS: Patients in the RIC group were older than those in the STAND group, and had a higher proportion of non-early disease phases including a prior autologous HSCT in 39%. Median follow-up for survivors was 28 and 15 months in the STAND and RIC groups (P < 0,001), respectively. Cumulative incidence of TRM at 2 yr was 30% [95% confidence interval (CI) 22-41%] for the STAND group and 22% (95% CI 13-37%) for the RIC group [non-significant (NS)]. Factors associated with a higher TRM in multivariate analysis were: STAND vs. RIC conditioning regimen [relative risk (RR) 5.4; 95% CI 2.3-12.8; P < 0.001]; age > or =45 yr vs. <45 yr (RR 5; 95% CI 2.4-10.8, P < 0.001); second vs. first HSCT (RR 2.8, 95% CI 1.3-6.3, P = 0.01) and non-T-cell-depleted vs. T-cell-depleted graft (RR 2.7, 95% CI 1.3-5.8, P = 0.009). Overall survival (OS) at 2 yr was 52.5 +/- 10.4% for STAND group and 59 +/- 16.8% in RIC group. Factors associated with poorer OS in multivariate analysis were: STAND vs. RIC conditioning regimen (RR 3.4, 95% CI 1.7-6.9, P = 0.001); age > or =45 vs <45 yr (RR 2.5, 95% CI 1.4-4.5, P = 0.002) and diagnosis [other than chronic myeloid leukemia (CML) vs. CML] (RR 2.6, 95% CI 1.2-5.7 P = 0.02). CONCLUSIONS: Our results indicate that the introduction of RIC allogeneic HSCT for patients at high risk for TRM (advanced age, prior HSCT and non-T-cell depletion) leads to a reduction in the TRM and improvement in the OS.     

Risk assessment and outcome of chronic graft-versus-host disease after allogeneic peripheral blood progenitor cell transplantation in pediatric patients

We retrospectively evaluated the incidence, risk factors for chronic graft-versus-host disease (cGvHD) and outcome in 80 pediatric patients (36 male) (median age 13 years) who underwent allogeneic peripheral blood progenitor cell transplantation. Patients were grafted from an HLA-identical sibling after myeloablative conditioning (total body irradiation (TBI) based 52; non-TBI 28). GvHD prophylaxis used were: cyclosporin A (CsA)+ short methotrexate (MTX) in 52 and CsA+/-prednisone in 28. The median number of CD34+ cells infused were 5.8 x 10(6)/kg (range: 1.4-32.8). The median follow-up was 24 months (range: 3-94). In all, 28 patients had cGvHD (confidence interval (CI): 54.2+/-10%). Factors that were significant on univariate analysis were diagnosis (P=0.03) and GvHD prophylaxis administered (P=0.04). On multivariate analysis, only GvHD prophylaxis used was associated with a significant risk of cGvHD (hazard ratio (HR): 3.94; 95% CI: 1.41-10.91, P=0.009). The CI of cGvHD for patients receiving CsA+MTX was 40.9+/-12 vs 76.5+/-18% for patients who did not (P=0.03). The probability of relapse was 36+/-6% for all patients (12.5+/-8% for patients with cGvHD vs 47.9+/-8% without cGvHD). The probability of disease-free survival was better for patients with cGvHD (69.9+/-10 vs 37.9+/-7%; HR: 3.59, 95% CI: 1.47-5.56; P=0.001). Our data suggest that the GvHD prophylaxis used is the most relevant predictor of cGvHD. Patients with cGvHD had a lower risk of relapse and a better survival.     

Allogeneic stem cell transplantation with reduced-intensity conditioning is potentially feasible as an outpatient procedure

Allogeneic stem cell transplantation (allo-SCT) after a reduced-intensity conditioning (RIC) protocol is associated with decreased short-term toxicity. This suggests that the procedure could be performed on an outpatient basis. We analysed the incidence and risk factors of grade >or=2 conditioning-related toxicities (CRTs) as a hallmark for hospital admission, in 41 consecutive patients allografted from an HLA identical sibling after RIC. The RIC regimen consisted of fludarabine plus melphalan for lymphoid malignancies, and fludarabine plus busulphan for myeloid malignancies. In all, 11 patients (27%) did not experience any toxicity. The more frequent CRTs observed were neutropenic fever and gastrointestinal toxicity. The median duration of hospitalisation was 27 (range, 17-50) days. If allo-SCT had been planned as an outpatient procedure and admission indicated only in the case of >or=2 CRTs, the inpatient period would have decreased to 9 (range, 0-33) days (P<0.001). No risk factors for CRTs were identified. Allo-SCT after an RIC regimen is a well-tolerated procedure. Our results warrant a prospective pilot trial of nonmyeloablative allo-SCT performed in the outpatient setting.     

Increased gene transfer into human hematopoietic progenitor cells by extended in vitro exposure to a pseudotyped retroviral vector

Retroviral-mediated gene transfer is the most attractive modality for gene transfer into hematopoietic stem cells. However, transduction efficiency has been low using amphotropic Moloney murine leukemia virus (MoMLV) vectors. In this study, we investigated modifications of gene transfer using amphotropic MoMLV vectors in cell-free supernatant for their ability to increase the currently low transduction of both committed hematopoietic progenitors, granulocyte-macrophage colony- forming units (CFU-GMs), and their precursors, long-term culture- initiating cells (LTC-IC). First, based on the observation that bone marrow cells express more gibbon ape leukemia virus (GALV) receptor (Glvr-1) than amphotropic receptor (Ram-1), PG13/LN, which is a MoMLV vector pseudotyped with the GALV envelope, was compared with the analogous amphotropic envelope vector (PA317/LN). Second, progenitor cell transduction efficiency was compared between CD34 enriched and nonenriched progenitor populations. Third, the duration of transduction in vitro was extended to increase the proportion of progenitor cells that entered cell cycle and could thereby integrate vector cDNA. In 20 experiments, 1 x 10(6) marrow or peripheral blood mononuclear cells (PBMCs)/mL were exposed to identical titers of pseudotyped PG13/LN vector or PA317/LN vector in the presence of recombinant human interleukin-1 (IL-1), IL-3, IL-6, and stem cell factor (SCF; c-kit ligand) for 5 days. 50% of fresh vector supernatant was refed daily. Hematopoietic progenitor cells as measured by G418-resistant granulomonocytic colony (CFU-GM) formation were transduced more effectively with PG13/LN (19.35%) than with PA317/LN (11.5%, P = .012). In 11 further experiments, enrichment of CD34 antigen positive cells significantly improved gene transfer from 13.9% G418-resistant CFU-GM in nonenriched to 24.9% in CD34-enriched progenitor cells (P < .01). To analyze gene transfer after extended growth factor-supported long-term culture, 1 x 10(6) marrow cells/mL were cultured with IL-1, IL-3, IL-6, and SCF (50 ng/mL each) for 1, 2, and 3 weeks. Fifty percent of PG13/LN supernatant with growth factors was refed on 5 days per week. Five percent of marrow CFU-GM and 67% of LTC-IC were G418 resistant at 1 week (n = 4), 60% of CFU-GM and 100% of LTC-IC were resistant at 2 weeks (n = 2) and 74% of CFU-GM (n = 4) and 82% of LTC-IC (n = 2) were resistant at three weeks.(ABSTRACT TRUNCATED AT 400 WORDS)     

Error-prone mammalian female meiosis from silencing the spindle assembly checkpoint without normal interkinetochore tension

It is well established that chromosome segregation in female meiosis I (MI) is error-prone. The acentrosomal meiotic spindle poles do not have centrioles and are not anchored to the cortex via astral microtubules. By Cre recombinase-mediated removal in oocytes of the microtubule binding site of nuclear mitotic apparatus protein (NuMA), which is implicated in anchoring microtubules at poles, we determine that without functional NuMA, microtubules lose connection to MI spindle poles, resulting in highly disorganized early spindle assembly. Subsequently, very long spindles form with hyperfocused poles. The kinetochores of homologs make attachments to microtubules in these spindles but with reduced tension between them and accompanied by alignment defects. Despite this, the spindle assembly checkpoint is normally silenced and the advance to anaphase I and first polar body extrusion takes place without delay. Females without functional NuMA in oocytes are sterile, producing aneuploid eggs with altered chromosome number. These findings establish that in mammalian MI, the spindle assembly checkpoint is unable to sustain meiotic arrest in the presence of one or few misaligned and/or misattached kinetochores with reduced interkinetochore tension, thereby offering an explanation for why MI in mammals is so error-prone.