G-CSF For Stem Cell Mobilization Research Articles

Surface CD52, CD84, and PTGER2 mark mature PMN-MDSCs from cancer patients and G-CSF-treated donors

Precise molecular characterization of circulating polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) is hampered by their mixed composition of mature and immature cells and lack of specific markers. Here, we focus on mature CD66b+CD10+CD16+CD11b+ PMN-MDSCs (mPMN-MDSCs) from either cancer patients or healthy donors receiving G-CSF for stem cell mobilization (GDs). By RNA sequencing (RNA-seq) experiments, we report the identification of a distinct gene signature shared by the different mPMN-MDSC populations under investigation, also validated in mPMN-MDSCs from GDs and tumor-associated neutrophils (TANs) by single-cell RNA-seq (scRNA-seq) experiments. Analysis of such a gene signature uncovers a specific transcriptional program associated with mPMN-MDSC differentiation and allows us to identify that, in patients with either solid or hematologic tumors and in GDs, CD52, CD84, and prostaglandin E receptor 2 (PTGER2) represent potential mPMN-MDSC-associated markers. Altogether, our findings indicate that mature PMN-MDSCs distinctively undergo specific reprogramming during differentiation and lay the groundwork for selective immunomonitoring, and eventually targeting, of mature PMN-MDSCs.

Blast Clearance after High Dose-Melphalan Conditioning for Allogeneic Stem Cell Transplantation in Relapsed and Refractory Acute Myeloid Leukemia

Introduction: For patients (pts) with relapsed or refractory acute myeloid leukemia (r/r AML) allogeneic stem cell transplantation (ASCT) has become an established highly effective and potential curative treatment option. Even for pts with active disease, direct ASCT using sequential conditioning regimens has shown promising outcomes. In this retrospective study, we examined prognostic factors for long-term survival in r/r AML pts with active disease with special focus to the prognostic value of blast clearance during condition therapy. Patients and Methods: 186 r/r AML pts treated with sequential conditioning regimens at our center between 2014-2023 were included in our analysis. Patients underwent high-dose melphalan (100 - 140 mg/m 2, day -11 prior ASCT) followed by either fractionated total body irradiation with 8 Gy (TBI, n = 71) or non-TBI regimens (busulfan, n = 101, or treosulfan, n = 14) in combination with fludarabin (120 - 150 mg/m 2) from day -6 before ASCT. TBI-based conditioning was applied almost exclusively in patients aged < 60 years. Graft versus host-disease (GvHD) prophylaxis consisted of calcineurin inhibitors, mycophenolate and anti-T-lymphocyte globulin. In 180 out of 186 patients, blast clearance was assessed by cytologic and flow cytometric blast count via bone marrow (BM) aspirate in median 5 days after Melphalan and prior to continuation of the sequential conditioning therapy. Blast clearance was defined as cytologic BM blast count < 5% and < 0.1% BM cells with leukemia-associated immunophenotype in flow cytometry. Results: Median pts age was 67 years (range 45 - 76 years) in the non-TBI group and 51 years (range 19 - 71 years) in the TBI group, respectively. Median follow up of surviving patients was 46 months. As expected, comorbidities and disease-specific factors varied between these groups. HCTCI scores > 3 points were observed in 14% of TBI pts compared to 32% in non-TBI pts ( p .01) and 45% versus 54% harbored adverse risk genetics according to European Leukemia Net (ELN) 2017 classification ( p .41), respectively. In the non-TBI group, 38% of the pts had a secondary or therapy-related AML compared to 20% of pts in the TBI group ( p .03). HLA-mismatched (<10/10 matched) donor grafts were transplanted in 21% (TBI) vs. 20% (non-TBI) of the pts. 185 of 188 pts received GCS-F mobilized stem cell grafts; 3 pts received a bone marrow graft. Kaplan-Meier estimates for overall survival (OS) with and without blast clearance at 2 years were 69.6% (95% CI 60.1-80.6%) vs. 58% (95% CI 48.8-69.1%, p .33), for event free survival (EFS, event defined as death or overt relapse) 58.9% (95% CI 49-70.8%) vs. 46.1% (95% CI 36.7-58.1%, p .2), respectively. We included the re-occurrence / persistence of defined molecular and cytogenetic markers or decreasing CD34 + bone marrow chimerism (< 95%) after transplant as measures for impending relapse as a modified EFS. The EFS including impending relapse was 49.8% (95% CI 40-62%) vs. 36.4% (27.7-47.8%) after 2 years. A non-significant trend with reduced relapse risk for those patients who achieved blast clearance after Melphalan ( p .1, HR 0.73) was observed. Most patients with impending relapse showed similar survival as patients without evidence of relapse after ASCT. In multivariate cox regression, age, HCTCI scores > 3 points, adverse risk according to ELN 2017 definitions and donor mismatch < 10/10 resulted in adverse prognosis. Especially, patients with mismatched donors displayed highly significant inferior outcomes. Both leukemic burden prior to ASCT as well as blast clearance after melphalan showed no significant correlation with clinical outcome parameters. Conclusion: Sequential conditioning regimens followed by ASCT offer long-term survival for more than 50% of pts with active relapsed or refractory AML. Patients who did not achieve complete blast clearance during conditioning therapy showed a trend towards higher relapse risk after ASCT which did not result in inferior survival. This underscores the importance of close monitoring and early interventions such as accelerated immunosuppression tapering, preemptive donor lymphocyte infusions and targeted therapies in case of impending relapse after ASCT.

EE56 Cost-Effectiveness Analysis of Motixafortide on Top of G-CSF for Stem Cell Mobilization for Autologous Bone Marrow Transplantation in Patients with Multiple Myeloma

The GENESIS trial demonstrated that motixafortide (M) + G-CSF (G, growth factor) mobilized significantly more stem cells for autologous transplantation (ASCT) in patients with multiple myeloma (MM) versus G alone. This study analyzed resource use (HRU) alongside the GENESIS trial and used the findings to assess cost-effectiveness of M+G vs G.

Plerixafor combined with G-CSF for stem cell mobilization in children qualified for autologous transplantation- single center experience

Failure of autologous peripheral blood CD34+ stem cells collection can adversely affect the treatment modality for patients with hematological and nonhematological malignant diseases where high dose chemotherapy followed by hematopoietic stem cell transplantation has become part of their treatment. Plerixafor in conjunction with G-CSF is approved for clinical use as a mobilization agent. The clinical efficacy of Plerixafor in CD34+ cells collection was analyzed in our institution. A total of 13 patients aged 1–15,5 years received Plerixafor in combination with G-CSF: 7 with neuroblastoma, 2 with Ewing’s sarcoma and single patients with Hodgkin’s lymphoma, germ cell tumor, retinoblastoma and Wilms tumor. Twelve patients (923%) achieved CD34+ cell counts of ≥ 20 × 106/L after 1–7 doses of Plerixafor. The average 9,9 - fold increase in number of CD34+ cells were achieved following the first dose and 429 - fold after second dose of plerixafor. Among the 13 patients, 12 yielded the minimum required cell collection of 2 × 106/kg within an average of 2 doses of Plerixafor. The mean number of apheresis days was 1.75. The median total number of collected CD34+ cells was 982 × 106/kg. Plerixafor enables rapid and effective mobilization, and collection of sufficient number of CD34+ cells.

G-CSF Infusion for Stem Cell Mobilization Transiently Increases Serum Cell-Free DNA and Protease Concentrations.

G-CSF for stem cell mobilization increases circulating levels of myeloid cells at different stages of maturation. Polymorphonuclear cells (PMNs) are also mobilized in high numbers. It was previously reported that G-CSF primes PMNs toward the release of neutrophils extracellular traps (NETs). Since NETs are often involved in thrombotic events, we hypothesized that high G-CSF blood concentrations could enhance PMN priming toward NET formation in healthy hematopoietic stem cell donors, predisposing them to thrombotic events. However, we found that G-CSF does not prime PMNs toward NETs formation, but increases the serum concentration of cell-free DNA, proteases like neutrophils elastase and myeloperoxidase, and reactive oxygen species. This could possibly create an environment disposed to induce thrombotic events in the presence of additional predisposing factors.

Myeloma Patients Relapsing after First Line Treatment with Tandem Auto/Allo Transplant or Auto Transplant Only Have Similar Outcomes.

<h3>Background</h3> A better survival in patients with multiple myeloma (MM) progressing after tandem autologous (auto)/allogeneic (allo) hematopoietic stem cell transplantation (HSCT) has been previously reported (Htut M. et al. BBMT 2018), suggesting a persistent graft-versus-multiple myeloma (GvMM) effect even after relapse. We sought to confirm this observation in a homogeneous cohort of MM patients who relapsed after upfront tandem auto/allo HSCT in our institution. <h3>Methods</h3> 92 consecutive, newly diagnosed MM patients who received tandem auto/allo HSCT were paired with 81 patients who received auto HSCT only between 2001 and 2010. Patients pairing criteria were age ≤ 65 years at diagnosis, Durie-Salmon 1B, 2 or 3, a glomerular filtration rate ≥ 60 mL/min, only one line of induction treatment, absence of progression within 4 months of auto HSCT and cytogenetics (if available). After their 1^st auto HSCT with high dose melphalan, all allo transplant recipients received an outpatient nonmyeloablative conditioning of fludarabine 30 mg/m² and cyclophosphamide 300 mg/m² × 5 days followed by G-CSF mobilized stem cells from a matched sibling donor. <h3>Results</h3> Median age in the auto/allo group was 53 years, compared to 57 years in the auto group (p<0.001). Both groups were similar for sex, immunoglobulin isotype, Durie-Salmon and ISS stages. With a median follow-up of 13.1 and 10.2 years (p<0.001), respectively, median overall survival (OS) in the tandem group has not been reached, compared to 6.1 years in the auto group only (p<0.001, Fig. 1). OS and PFS at 10 years in tandem and auto groups were 61% vs 37% (p<0.001) and 49% vs 22% (p<0.001), respectively. Disease progression occurred in 46 of 92 tandem recipients and 63 of 81 auto recipients, with an estimated 10-year cumulative incidence of progression (CIP) significantly lower in the tandem group (50% vs 77%; p<0.001, Fig. 2). Median OS at 10 years after 1^st progression was 39% in the tandem group and 22% in the auto group (p=0.062, Fig. 3). In multivariate analysis of factors associated with CIP, the only significant variable was tandem transplant (hazard ratio 0.44; 95% CI: 0.24-0.80, p=0.008), independently from age, ISS stage, type of induction and response before 1^st auto HSCT. Main cause of death was MM in both groups. <h3>Conclusion</h3> Tandem auto/allotransplant enables long-term survival and offers a potentially curative option in selected newly diagnosed MM patients. At time of 1^st relapse, tandem auto/allo transplant does not confer a significant outcome advantage compared to auto HSCT only.

Combining Brentuximab Vedotin with DHAP as Salvage Treatment in Relapsed/Refractory Hodgkin Lymphoma: The Phase II HOVON/LLPC Transplant BRaVE study

IntroductionAchieving a PET-negative metabolic (m)CR with salvage chemotherapy prior to autologous stem cell transplantation (ASCT) in relapsed/refractory Hodgkin lymphoma (R/R HL) is a strong predictive factor for long-term progression-free survival (PFS). In a phase I dose-escalation trial we have shown a favorable toxicity profile of 3 cycles of DHAP in combination with brentuximab vedotin (BV) with a high mCR rate (12/12 patients). A subsequent phase II study in 55 patients has been performed; the 6 patients treated at full dose of BV-DHAP in the phase I part were added to the current analysis.MethodsBV was given at a fixed dose of 1.8 mg/kg on day (d) 1 of 3 cycles of DHAP q 3 weeks (dexamethasone 40 mg iv d 1-4, cisplatin 100 mg/m² iv d1 and cytarabine 2x2 g/m² iv d2). Cycle 2 was used for stem cell mobilization; after the 1st and 3rd cycle patients received pegylated G-CSF to prevent prolonged neutropenia and dose delays. The primary endpoint of the study was the mCR rate after 3 cycles of BV-DHAP based on central PET-review. Patients with a partial or complete response proceeded to high dose chemotherapy (BEAM) and ASCT.ResultsTwenty-three of the 61 patients (29 males; median age 29 yrs, range 19-71) had not achieved a CR to 1st line treatment (37%), which consisted of ABVD (n=45), (escalated) BEACOPP (n=11) or other regimens (n=5). The median time from response to 1st line treatment to relapse was 6 months (range 0-160 months); 38 patients (62%) had either primary refractory disease or early relapse (<1 year).All patients received the 1st cycle of BV-DHAP, 90% completed all 3 cycles and 87% underwent ASCT. G-CSF mobilized stem cells were harvested successfully after the 2nd cycle with 1 apheresis in all patients (median yield: 6x106 CD34+/kg; range: 2-23). Based on intention to treat analysis 48 patients achieved a metabolic CR after 3x BV-DHAP (mCR rate 79% (n=48/61)), 5 patients had a metabolic PR (8%) and 4 had PD (6.5%). Four patients went off study before the first evaluation (1 PD after cycle 1, 1 liver function abnormalities after cycle 2, 2 withdrew because of emotional problems). After ASCT 4 out of 5 patients with mPR converted to an mCR. At a median follow-up of 20.9 months the 2-year PFS is 76% (95% CI 65-89), and the OS projected at 2 years is 92% (95% CI 84-100).Hematologic toxicity after BV-DHAP consisted of neutropenia grade 3/4 in up to 63% of patients and thrombocytopenia grade 3/4 in up to 81% of patients. Only 3 patients had a bleeding event (epistaxis (n=2) and menorrhagia (n=1), all recovered without sequelae after platelet transfusion). Febrile neutropenia or infections after BV-DHAP occurred in 18 patients (15 grade 3 and 3 grade 4). A total of 21 SAE's other than fever/infections were reported, with kidney dysfunction (n=4; most likely related to cisplatin), malaise (n=3), nausea/vomiting (n=3) and liver function abnormalities (n=3) occurring in 3 or more patients. 11 patients had peripheral neuropathy (PN) already at baseline (10 grade 1, 1 grade 2); worsening of PN was not observed in those patients. New onset PN was seen in 19 patients (15 grade 1, 4 grade 2); no grade 3/4 PN was observed.Three deaths occurred during the study period, 1 encephalitis (exact cause unknown), 1 veno-occlusive disease, both after BEAM/ASCT and 1 trauma capitis (unrelated). One patient who refused further treatment after cycle 1 and went off study died of progressive disease.ConclusionsSalvage immunochemotherapy with 3 cycles of BV-DHAP induces a high mCR rate of 79% in patients with R/R HL, which is an optimal starting point for consolidation with BEAM and ASCT and may contribute to a higher cure rate. The toxicity of combining BV and DHAP is acceptable and mainly consists of manageable hematologic toxicity and fever/infections. [Display omitted] DisclosuresHagenbeek:Millennium/Takeda: Consultancy, Honoraria, Research Funding. Morschhauser:Janssen: Other: Scientific Lectures; BMS: Membership on an entity's Board of Directors or advisory committees; Epizyme: Consultancy; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees. Lugtenburg:Millennium/Takeda: Consultancy, Research Funding; Servier: Consultancy, Research Funding; Roche: Consultancy; BMS: Consultancy; Sandoz: Consultancy; Genmab: Consultancy. Gastinne:Millennium/Takeda: Honoraria. Tonino:Takeda: Consultancy, Honoraria. Kersten:Millennium/Takeda: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Gilead: Honoraria; Kite Pharma: Honoraria; Novartis: Honoraria.

Clinical-grade generation of peptide-stimulated CMV/EBV-specific T cells from G-CSF mobilized stem cell grafts

BackgroundA major complication after allogeneic hematopoietic stem cell transplantation (aSCT) is the reactivation of herpesviruses such as cytomegalovirus (CMV) and Epstein–Barr virus (EBV). Both viruses cause significant mortality and compromise quality of life after aSCT. Preventive transfer of virus-specific T cells can suppress reactivation by re-establishing functional antiviral immune responses in immunocompromised hosts.MethodsWe have developed a good manufacturing practice protocol to generate CMV/EBV-peptide-stimulated T cells from leukapheresis products of G-CSF mobilized and non-mobilized donors. Our procedure selectively expands virus-specific CD8+ und CD4+ T cells over 9 days using a generic pool of 34 CMV and EBV peptides that represent well-defined dominant T-cell epitopes with various HLA restrictions. For HLA class I, this set of peptides covers at least 80% of the European population.ResultsCMV/EBV-specific T cells were successfully expanded from leukapheresis material of both G-CSF mobilized and non-mobilized donors. The protocol allows administration shortly after stem cell transplantation (d30+), storage over liquid nitrogen for iterated applications, and protection of the stem cell donor by avoiding a second leukapheresis.ConclusionOur protocol allows for rapid and cost-efficient production of T cells for early transfusion after aSCT as a preventive approach. It is currently evaluated in a phase I/IIa clinical trial.

A Pilot Study of Eltrombopag Plus G-CSF for Human CD34+ Cell Mobilization in Patients with Multiple Myeloma Undergoing Autologous Stem Cell Transplant

Background: Administration of recombinant human thrombopoietin (rhTPO) with G-CSF for stem cell mobilization is associated with high CD34+ stem cell yield, rapid neutrophil recovery following autologus transplantation (ASCT), and decreased red blood cell (rbc) and platelet (plt) transfusions (Solomo, G. et al. Blood 1999). However, clinical development of rhTPO was complicated by the formation of neutralizing anti-TPO antibodies (Li, J. et al. Blood 2001), prompting discontinuation of further clinical development of recombinant TPO. Eltrombopag (Elt) is an orally bioavailable small molecule thrombopoietin receptor (TPO-R) agonist approved by the FDA for treatment of chronic immune thrombocytopenic purpura (ITP). In vitro studies have demonstrated that Elt promotes megakaryocyte proliferation and differentiation of CD34+ bone marrow progenitor cells (Erickson-Miller CL Stem Cells 2009), suggesting that Elt might be a surrogate for rhTPO for stem cell mobilization. In this pilot trial, we evaluated the combination of Elt plus standard G-CSF and cyclophosphamide (C) for stem cell mobilization in patients (pts) with multiple myeloma (MM), a disease for which ASCT remains a standard of care (Blade et al. Blood 2010).Methods: Primary objectives included determination of the median number of CD34+ cells/kg mobilized and the maximum tolerated dose (MTD) of Elt. Pts had MM that was stable or responsive to at least two cycles of chemotherapy with plans for stem cell mobilization and ASCT. Four pts were to be enrolled in each of four dose escalation arms in which they received 0 (Arm D), 50 (Arm A), 100 (Arm B), or 150 mg (Arm C) of eltrombopag in combination with standard C + G-CSF. Adverse events (AEs) were graded by NCI-CTCAE v4.Results: 17 pts have been screened and enrolled to date. Two patients withdrew consent prior to receiving Elt and were excluded from statistical analysis. 15 patients have completed participation in the study to date and two patients remain to be enrolled in Arm C. The first subject in Arm A experienced delayed engraftment that was determined to be unrelated to ELT; rather, the event was attributed to administration of a one-time high dose of corticosteroid for management of a severe hypersensitivity reaction to DMSO that occurred during stem cell infusion. A second subject in Arm A had undergone mobilization with Elt prior to the previously described delayed engraftment event, and to ensure safety underwent a second mobilization with G-CSF and plerixafor. During ASCT, this patient received cells from the second mobilization procedure. While neither event met criteria for a dose-limiting toxicity, the protocol was amended such that three additional patients enrolled in Arm A underwent two rounds of mobilization - the first with Elt plus C and G-CSF and a second with G-CSF plus plerixafor - and received as part of ASCT cells mobilized with Elt. Each of these patients engrafted successfully. The median number of CD34+ cells/kg collected during the first collection day of apheresis in Arms D, A, B, and C was 8.0, 11.0, 15.3, and 26.4. The median total number of CD34+ stem cells collected following mobilization with Elt plus C and G-CSF in Arms D, A, B, and C was 13.2, 12.7, 15.4, and 26.4. The percentage of patients in Arms D, A, B, and C who achieved a target collection of 8 x 10^6 CD34+ stem cells in one collection day was 50, 60, 75, and 100%. There have been no severe adverse events related to Elt .Conclusions: Administration of Elt in combination with C plus G-CSF for stem cell mobilization in pts with MM undergoing ASCT was safe and well tolerated, with no DLTs or severe AEs attributable to Elt. The small size of this pilot study precludes formal statistical comparison of outcomes across treatment Arms, but there appears to be a trend toward increase in yield of CD34+ cells and decrease in apheresis procedures required with increasing doses of Elt. DisclosuresRichardson:Jazz Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Bortezomib Consolidation after Nonmyeloablative Allogeneic Stem Cell Transplantation Leads to a High Incidence of Immunophenotypic Complete Response in Young and/or High-Risk Multiple Myeloma Patients

Introduction: Allogeneicstem cell transplantation (alloSCT) is the only curative modality for newly diagnosed multiple myeloma (NDMM) patients (pts). However, we have previously shown in a large cohort of 92 pts that relapse remains common (49%) and the incidence/severity of chronic GVHD is significant (79%) after tandem auto-allo SCT in NDMM pts (Ahmad et al. BMT 2016;51:529). We hypothesized that a tandem auto-nonmyeloablative (NMA) alloSCT followed by bortezomib (btz) consolidation might be safe, while decreasing both the severity/incidence of chronic GVHD and the risk of relapse in young and/or high-risk NDMM pts. In addition, we hypothesized that btz might further increase depth of responses after alloSCT.Methods: NDMM pts with either ISS stage III, plasma cell leukemia, abnormal cytogenetics defined as t(4;14) with ISS II or III, t(14;16), t(14;20), 17p-, 1p-, or 1q+ in ≥ 10% of purified plasma cells or age ≤ 50 years with a 6/6 sibling or 8/8 unrelated donor were prospectively enrolled in this phase II trial. After a btz-based induction with ≥ partial response and autologous (A) SCT, outpatient NMA alloSCT was performed with either a conditioning of fludarabine 30 mg/m2 x 5 days and cyclophosphamide 300 mg/m2 x 5 days (sibling donor) or fludarabine 30 mg/m2 x 3 days and TBI 2Gy (unrelated donor), followed by G-CSF mobilized stem cells infusion. Acute GVHD prophylaxis consisted of tacrolimus and mycophenolate mofetil. Btz 1.3 mg/m2 SC every 2 weeks was started on day +120 after alloSCT for 1 year. Bone marrow aspirates before alloSCT, before starting btz and every 3 months thereafter were prospectively collected for 2 years in order to assess the impact of btz on minimal residual disease (MRD) by a highly sensitive (≥10-5) multiparametric flow cytometry using the 8-color Euroflow protocol evaluating ≥ 10 x 106 cells/specimen. MRD negativity was defined as the detection of < 30 clonal aberrant plasma cells. Response evaluation is based on IMWG criteria including immunophenotypic complete response (iCR) defined as a stringent CR (sCR) plus a negative MRD. Immunophenotypic remission (iR) is defined as MRD negativity regardless of other disease status.Results: As of 06/30/2016, 20 MM pts have been enrolled and 18 allotransplanted (8 siblings; 10 unrelated); median age is 54.5 (range 35-63) years. Of these pts we report: age ≤ 50 (n=6), ISS stage III (n=10) or poor risk cytogenetics (n=7; 5 with 1q+, 2 with t(4;14)). Pts received initial induction with VTD (n=7) or CyBorD (n=11), followed by ASCT (melphalan 200 mg/m2; median CD34+/kg infused: 7.2 x 106). Median times from diagnosis to ASCT and from ASCT to alloSCT were 7.0 (range: 5.3-11) and 4.8 (range: 3.0-7.0) months, respectively. All pts allotransplanted (median CD34+/kg infused: 7.4 x 106) engrafted. With a median follow-up of 282 (range: 22-562) days after alloSCT, 15 pts have received 221 of 239 (92%) planned doses of btz. Observed grade ≥3 non-hematologic adverse events include btz-induced diarrhea (n=1), herpes mucositis despite adequate prophylaxis (n=1), viral hemorrhagic cystitis (n=3) and asymptomatic EBV reactivation (n=4) requiring rituximab. In contrast, CMV reactivation was infrequent. None of the pts developed or exacerbated pre-existing peripheral neuropathies. Fifteen pts were followed ≥ 7 months after alloSCT; acute GVHD occurred in 3 pts (1 grade II; 2 grade III) and chronic in 10 (67%; 3 mild; 7 moderate). Two pts died from grade III acute GVHD. Nine pts (60%) required hospitalization for a median of 13 days (8-184). Response rates after induction, ASCT, alloSCT and btz are shown in Table 1. Most notably, depth of response improved after btz, with 6 pts (40%; 2 with 1q21, 1 with t(4;14), 2 normal and 1 unknown) in iCR and 4 pts (27%; 1 with 1q21, 2 normal and 1 unknown) in sCR. An additional 20% of pts not in iCR or sCR were in iR with negative MRD. No patient developed extramedullary disease.Conclusions: Our major finding is a high sCR + iCR of 67% in young and/or high-risk NDMM pts following tandem auto-alloSCT and btz consolidation. Although our follow-up is still short, our results are encouraging for an eventual low relapse rate. Additionally, administration of btz 1.3 mg/m2 SC every 2 weeks starting on day +120 after alloSCT is safe and well tolerated. Finally, close monitoring of EBV should be performed prospectively in alloSCT recipients who receive a proteasome inhibitor in order to better assess the risk of viral reactivation. [Display omitted] DisclosuresSebag:Celgene: Honoraria; Novartis: Honoraria; Janssen: Honoraria.

Factors associated with bone marrow stem cell yield for pediatric allogeneic stem cell transplantation: The impact of donor characteristics.

The aim of this study was to investigate the effects of donor characteristics on CD34+ cell yield in BM harvest. Between April 2010 and November 2013, consecutive donors who underwent BM harvesting in our BM transplantation unit were retrospectively investigated. Donors were classified into two groups: those who donated BM without mobilization (steady-state BM donors) and those who received G-CSF for stem cell mobilization (G-CSF-primed BM donors). Donor characteristics (age, gender, race, body weight, BMI, and laboratory factors including donor's leukocyte, platelet, and monocyte) and their relationship with total nuclear cell and CD34+ cell numbers has been evaluated. A total of 64 healthy related donors (29 males/35 females, median age 11.2years; 49 [76.6%] younger than 18 and 36 [56.3%] younger than 12years) were included in the study. The median CD34+ cell yield in the harvest was 0.12×106 /L (0.02-0.21) in SS-BM donors and 0.18×106 /L (0.09-0.67) in GP-BM donors (P=.03). Median of CD34+ cell count given to recipients was 2.6×106 /recipient body weight (1.3-19.3) in SS-BM yields and 3.8×106 /recipient body weight (1.1-10.2) in GP-BM yields, respectively. Multiple regression analysis showed that donor height and pre-G-CSF platelet were the most important parameters to obtain a sufficient BM harvest. Our data suggest that the shorter donors and the donors with higher thrombocyte counts may offer more hematopoietic stem cell. The height and thrombocyte count of the donors should be taken into consideration before planning the targeted CD34+ cell count especially for pediatric donors.

Increased efficacy of intermediate-dose cytarabine + G-CSF compared to DHAP + G-CSF for stem cell mobilization in patients with lymphoma: an analysis by the polish lymphoma research group.

Salvage regimens, like DHAP (dexamethasone, cytarabine, and cisplatin) are frequently used for stem cell mobilization in lymphoma. The aim of this study was to compare the efficacy of DHAP + G-CSF with intermediate-dose cytarabine (ID-AraC) + G-CSF, recently proposed as an alternative schedule. Consecutive patients with Hodgkin's or non-Hodgkin lymphoma who had received at least 2 lines of chemotherapy, mobilized with either DHAP (n = 51) or ID-AraC (n = 50) + G-CSF were included in the analysis. AraC was administered at the dose of 400mg/m [1] bid intravenously for 2days followed by filgrastim starting from day 5. In the AraC group, 96% of patients collected at least 2 × 10 [2] CD34(+) cells/kg compared to 71% in the DHAP group (p = 0.0006). The CD34(+) cell yield was 9.3 (0-30.3) × 10 [2]/kg vs. 5.6 (0-24.8) × 10 [2]/kg, respectively (p = 0.006). A single apheresis was sufficient to achieve the threshold number of CD34(+) cells in 82% of the cases after AraC compared to 45% after DHAP (p = 0.001). We conclude that stem cell mobilization using ID-AraC is associated with a significantly higher efficacy than DHAP, allowing for collection of the transplant material in almost all patients with lymphoma. Our observation suggests that ID-AraC + G-CSF may be a preferable mobilization regimen in this setting.

Clinical outcomes and graft characteristics in pediatric hematopoietic stem cell transplantation: Effect of granulocyte-colony stimulating factor priming

In this study, we aimed to determine the effect(s) of G-CSF priming on graft and transplantation parameters and compare these findings with those obtained without priming.A total of 64 pediatric patients transplanted from HLA-matched family donors were enrolled in the study. Twenty-nine patients received G-CSF primed marrow (G-BM group) and 35 patients received steady state bone marrow (S-BM group). Number of total nucleated cells (TNC) and CD34+ cells, CFU-GM colony number, neutrophil and platelet engraftment times, total length of stay in hospital, overall and disease free survival, and occasions of acute and chronic GvHD has been compared between these two groups.Granulocyte colony stimulating factor primed bone marrow (G-BM) yielded higher numbers of CD34+ cells, TNCs, and CFU-GM colony numbers compared to those obtained in S-BM. The neutrophil engraftment time, platelet engraftment time, length of stay in hospital, overall survival and disease free survival were not different between G-BM and S-BM groups. Also the cumulative incidence of grades II–IV acute and chronic GvHD were similar. It was observed that the use of G-CSF did not increase the risk of acute or chronic GvHD.We concluded that use of G-CSF for stem cell mobilization is an effective and safe method in children.

Efficacy and Risk Factors Analysis of Upfront Autologous Stem Cell Mobilization Using Plerixafor and Granulocyte-Colony Stimulating Factor (GCSF) in Patients with Multiple Myeloma

Background: G-CSF with or without cyclophosphamide has been commonly used in multiple myeloma (MM) for stem cell (SC) collection prior to autologous stem cell transplantation (ASCT). Several risk factors including age, prolonged exposure to lenalidomide, and low platelet count are associated with suboptimal stem cell harvest. Plerixafor selectively and reversibly binds to the chemokine receptor CXCR4 and blocks its interaction with stromal cell-derived factor-1α. This drug was approved by the FDA for stem cell mobilization in MM, based on phase III studies demonstrating the superiority of plerixafor and G-CSF over G-CSF alone in achieving a predetermined target yield of 6 × 106CD34+ cells/kg collected in < 2 phereses; however, this outcome is not clinically relevant. The purpose of this retrospective study is to examine the SC mobilization efficiency associated with plerixafor using a more clinically relevant outcome, and to identify risk factors associated with poor SC mobilization, including the potential impact of prior exposure to lenalidomide-containing regimens.Patients and methods: This retrospective study examined MM patients mobilized with plerixafor and G-CSF upfront as part of initial therapy at Memorial Sloan Kettering Cancer Center between 4/1/2009 and 8/1/2013. Baseline characteristics examined included age, race, gender, platelet count, WBC count, and marrow plasmacytosis prior to mobilization. Treatment characteristics examined included type of induction regimen (distinguishing regimens containing lenalidomide only, bortezomib only, or both), number of cycles received, time between last chemotherapy and SC mobilization, time between start of treatment and SC collection, and prior radiation. The primary endpoint was the rate of SC collection success, defined as the ability to collect at least 5 x 106CD34+ cells/kg during the first set of phereses, which would be sufficient for two ASCT. The secondary endpoint was SC collection efficiency, measured by the number of CD34+ cells yielded per pheresis performed during the first set of stem cell collection. Linear regression was used to examine the univariate effect of baseline and treatment variables on SC collection efficiency. Variables significant at the 0.05 level were entered into a multivariable model.Results: A total of 138 MM patients were mobilized with plerixafor and G-CSF before proceeding to stem cell collection. The rate of SC collection success was 92.8%. Due to this high success rate, we could not identify independent risk factors associated with poor SC mobilization. When considering SC efficiency as outcome, the average efficiency for the entire cohort was 7.25 x 10^6 CD34+ cells/kg/pheresis. Increased age (p=0.005), shorter time between treatment start and SC collection (p=0.05), higher number of cycles received during induction treatment (p=0.042), lower platelet count (p=0.009) and lower WBC prior to G-CSF (p=0.01), and exposure to lenalidomide only (p=0.011) were all identified as risk factors by univariate analysis. Only lower WBC prior to GCSF (p=0.009) maintained statistical significance after multivariate analysis.Conclusions: This retrospective study shows that plerixafor is a highly effective agent for SC mobilization and collection in MM patients, with only few patients failing to achieve the target collection regardless of baseline or treatment characteristics including prior lenalidomide exposure. However, we identified WBC prior to G-CSF administration as a predictor of SC collection efficiency. These results provide strong support to the upfront use of plerixafor and G-CSF for SC mobilization in MM patients. A cost analysis is currently in progress comparing this SC collection modality with other conventional means currently being employed in patients with MM. DisclosuresNo relevant conflicts of interest to declare.

Therapeutic Infusion of Partially HLA-Matched Third-Party Virus-Specific T Cells in HSCT Patients with Refractory Viral Infection

IntroductionAdoptive transfer of donor derived virus specific T cells (VST) can be effective therapy for infections in allogeneic HSCT recipients. However, this is not a practical strategy to treat acute infections due to the time required to prepare products and potential unavailability of transplant donors. To overcome this, treatment with cryopreserved partially HLA-matched T cells from third-party donors is being investigated. A recent report described disease resolution using cells matched at only one or two HLA alleles (Leen et al., (2013) Blood 121(26):5113-23). This less stringent requirement for matching would allow a small bank of cells to provide most patients with a therapeutic product. We describe the establishment of a virus specific T cell bank in Australia with centralized manufacturing by the Westmead Hospital BMT laboratory. The bank has been used to treat patients in multiple states in a Phase I clinical trial to treat patients who have failed antiviral pharmacotherapy.AimTo assess the safety and feasibility of treatment with partially HLA-matched VSTs derived from third-party donors for refractory cytomegalovirus (CMV), Epstein-Barr Virus (EBV), or adenoviral (AdV) infection in allogeneic HSCT patients.MethodsWe generated a bank of cryopreserved VSTs from peripheral blood or G-CSF mobilized stem cell product of healthy donors. Products were generated by co-culturing PBMC with dendritic cells loaded with overlapping peptides covering CMV pp65, AdV hexon or EBV BZLF1, LMP2A and EBNA1 proteins. Cultures were re-stimulated once with peptide loaded DC and cultured for 14 days with IL-2. Products were assessed for phenotype, sterility and specificity by MHC multimer staining where applicable or production of interferon-gamma in response to peptides by flow cytometry.Patients with persistent viral reactivation/infection after 2 weeks of standard therapy were eligible to receive up to 4 fortnightly infusions of 2x107 cells/m2partially HLA matched (minimum 1/6) CMV, EBV, or AdV specific T cells, and were followed for up to 12 months.ResultsT cell products were expanded from 25 donors to create a bank of 177 bags of VSTs (75 CMV, 47 AdV and 55 EBV). CMV specific products were predominantly T cells (mean 95.8±3%) with a higher proportion of CD8+ compared to CD4+ T cells (mean 66.6±23.9% versus 20.1±6.2%). Specificity was mapped by MHC multimer staining to epitopes restricted to common HLA types including HLA-A*0101, HLA-A*0201, HLA-A*2402, HLA-B*0702 and HLA-B*3501. AdV specific T cells had a higher proportion of CD4+ T cells (mean 64.6±23.8% versus 34.2±20.1% CD8 T cells). Specificity was mapped to CD8 epitopes restricted to HLA-A*0101 and HLA-A*2402 as well as 10 CD4 T cell epitopes restricted to three HLA-DRB1 alleles (DRB1*0301, DRB1*0701, DRB1*1501). EBV specific products contained a mix of CD8+ and CD4+T cells (mean 38.9%±18% AND 42.5±23.1% respectively). The antigen specificity of EBV products showed high variability between donors. Dominant responses to known MHC class I restricted epitopes were infrequent though responses were mapped to HLA-A*0201 and HLA-A*2402 restricted LMP2A epitopes, a HLA-B*0801 restricted BZLF1 epitope and a HLA-B*0702 restricted EBNA1 epitope. Based on HLA frequency analysis in the Australian recipient population we estimate 94%, 89% and 74% of patients would have access to a CMV, AdV and EBV specific product respectively with the current bank.To date nine patients have received VSTs, with median follow-up of 5.5 months (0-12 months). All patients had treatment resistant CMV after a median of 26 days (19-116 days) prior therapy. Six patients received a single infusion and 3 patients received 2, 3 and 4 infusions respectively. HLA matching ranged from 2-4/6 HLA match. There were no instances of 24hr infusion related toxicity. Follow-up data is available for 7 patients. One patient with chronic hepatitis C developed abnormal liver function tests 3 months post-infusion. One patient died from presumed progressive CMV disease 6 months post-enrolment. Five patients achieved a best response of CMV PCR negativity (2 with complete resolution of CMV-colitis). One patient has shown >50% reduction in CMV copy number over 3 weeks.ConclusionThe infusion of third party CMV specific T cells is a promising therapy that offers the advantage of rapid availability, centralized manufacturing and relatively low cost per dose when produced on a large scale. DisclosuresNo relevant conflicts of interest to declare.

Impaired Functionality of Antiviral T Cells in G-CSF Mobilized Stem Cell Donors: Implications for the Selection of CTL Donor

Adoptive transfer of antiviral T cells enhances immune reconstitution and decreases infectious complications after stem cell transplantation. Information on number and function of antiviral T cells in stem cell grafts is scarce. We investigated (1) immunomodulatory effects of G-CSF on antiviral T cells, (2) the influence of apheresis, and (3) the optimal time point to collect antiviral cells.CMV-, EBV- and ADV-specific T cells were enumerated in 170 G-CSF-mobilized stem cell and 24 non-mobilized platelet donors using 14 HLA-matched multimers. T-cell function was evaluated by IFN-γ ELISpot and granzyme B secretion. Immunophenotyping was performed by multicolor flow cytometry.G-CSF treatment did not significantly influence frequency of antiviral T cells nor their in vitro expansion rate upon antigen restimulation. However, T-cell function was significantly impaired, as expressed by a mean reduction in secretion of IFN-γ (75% in vivo, 40% in vitro) and granzyme B (32% target-independent, 76% target-dependent) as well as CD107a expression (27%). Clinical follow up data indicate that the first CMV-reactivation in patients and with it the need for T-cell transfer occurs while the donor is still under the influence of G-CSF.To overcome these limitations, T-cell banking before mobilization or recruitment of third party donors might be an option to optimize T-cell production.

Plerixafor and G-CSF For Autologous Stem Cell Mobilization In AL Amyloidosis: A Single Center Experience

Background Risk-adapted melphalan and stem cell transplant (SCT) is standard initial therapy for a minority of patients with systemic AL amyloidosis (Blood 2013;121: 5124; Blood 2011;118: 4298). Stem cell mobilization is often accomplished with high dose G-CSF (16μg/kg/d) (Blood 2011;118:4346). In the current era with effective new agents such as bortezomib, many AL patients are receiving initial therapy and achieving profound rapid cytoreduction with organ improvement (Blood 2012;119:4391; Blood 2011;118:86). But not all patients respond and in some cases the duration of response is limited. In addition, the use of SCT for consolidation after an initial response, although reasonable, has not been systematically evaluated. Whether SCT is employed as consolidation or as a second- or third-line option, the efficacy and tolerance of mobilization become important issues. Because AL patients have organ involvement limiting chemotherapy-based mobilization options, we decided to explore the option of Plerixafor and G-CSF for stem cell mobilization, based on the phase III experience in MM (Blood 2009;113:5720). We now report the first experience with this mobilization approach in AL. Patients and Methods Patients were evaluated and diagnosed by standard criteria including, in all cases, tissue biopsies showing amyloidosis. They were mobilized and collected between 4/16/12 and 6/19/13 with G-CSF 10μg/kg/d subcutaneously (SC) for 5 days (continued through collection process) and Plerixafor adjusted for renal function starting on day 4 and continuing until collection was completed. Results We report on 10 patients whose median age at mobilization was 58 years (range 46-72), 60% of whom were men. Median number of organs involved was 2 (range 1-3). Heart and kidneys were the most frequently involved organs (7 patients in each group). Median time from diagnosis to mobilization was 9 months (range 2-123). Eight patients had received prior bortezomib-based therapy. The median number of cycles was 3 (range 0-6). One had received a prior MEL 140 transplant 10 years prior and had relapsed, and 2 were treatment naïve, one of whom was 1 year status post orthotopic heart transplant. At the time of mobilization, 3 patients had non-responsive hematologic disease, 3 had achieved PR, 1 VGPR and 1 had achieved CR. Five patients had a creatinine ≥ 1.5 mg/dL including 2 patients on hemodialysis. The target cell dose was 10x106CD34/kg for all but one patient (with previous history of transplantation). The median number of collections was 2 (range 2-3). On day one, the median number of CD34+ cells collected per kg was 3.6 x106 (0.4-6x106) and on day two 6.4 x106 (2.7-19x106). The median total CD34+ cells collected per kg was 12.5x106 (5-18x106). Two patients had grade 1 bleeding from the catheter site during apheresis and one patient had dyspnea with suspected fluid overload which responded to a single dose of intravenous furosemide. There were no significant toxicities observed with Plerixafor in mobilization. All patients went on to receive high dose chemotherapy with melphalan followed by autologous stem cell transplant. The median length of hospital stay was 25 days (18-32). The median stem cell dose infused was 7.6x106CD34/kg and median days to ANC &gt; 500 was 11 (10-22), to platelets &gt; 20K untransfused 22 (15-44) and to lymphocytes &gt; 500/μl 14.5 (11-25). One patient who had VOD and persistent thrombocytopenia was given the remainder of his stem cells on day +31 with full recovery and normalization of the blood counts by day +65. Conclusions In the era of more effective initial therapies, an era in which AL patients are living longer, many with moderate organ damage, mobilization with Plerixafor and G-CSF was well tolerated and made it possible to collect ample numbers of CD34+ cells with limited leukaphereses in previously treated patients and in those with advanced renal failure. This approach not only allowed the collection of sufficient CD34+ cells for optimal immediate stem cell dosing but also permitted the cryopreservation of aliquots for post-SCT boost and potentially for future cell-based therapies. Disclosures: Comenzo: Millenium: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Prothena: Research Funding; Teva: Research Funding.

EPCR Limits Nitric Oxide Levels, Mediating Human and Murine Stem Cell Adhesion and Retention In The Bone Marrow, By Conjugating PAR1 and CXCR4 Signaling

Long term repopulating hematopoietic stem cells (LTR-HSC) in the murine bone marrow (BM) highly express endothelial protein C receptor (EPCR), yet the function of EPCR in HSC is incompletely defined. EPCR is expressed primarily on endothelial cells and has anti coagulation and anti inflammatory roles. While physiological stress due to injury or bleeding is a strong inducer of HSC mobilization and leukocyte production, a role for the coagulation protease thrombin, and its major receptor PAR1 in regulation of HSC has not yet been identified. We hypothesized that thrombin plays a role in HSC mobilization in the context of injury and that, conversely, signaling involving EPCR and its ligand activated protein C (aPC) play a regulatory role in HSC maintenance. Herein, we report that murine BM EPCRhigh stem cells display enhanced CXCL12 mediated adhesion and reduced migration capacitie, while motile circulating HSC in the murine blood and spleen lack high EPCR expression. Mechanistically, we found that EPCR is a negative regulator of nitric oxide (NO) levels. EPCRhigh stem cells display low intracellular NO levels, low motility, and increased adhesion to BM stroma. Furthermore, EPCRlow transgenic mouse cells displayed reduced stem cell adhesion to BM stroma and increased motility, manifested by reduced EPCRlow HSC in the BM and their corresponding increased levels in the blood. In vitro stimulation with the EPCR ligand, aPC, which we found to be physiologically expressed adjacent to small murine BM blood vessels, augmented EPCRhigh HSC adhesion and further limited their intracellular NO content by increasing eNOS phosphorylation at Thr495 in BM HSC, causing reduced production of NO. Conversely, administration of the pro-coagulant protease thrombin to mice induced PAR1 mediated EPCR shedding from BM HSC, followed by CXCR4 upregulation on HSC, and PAR1-mediated CXCL12 secretion by BM stromal cells. Together, these events lead to loss of retention and rapid stem cell mobilization to the blood. Interestingly, shedding of EPCR was found to be mediated by elevation of intracellular NO content, leading to EPCR co-localization with Caveolin. Correspondingly, thrombin failed to induce EPCR shedding and mobilization in eNOS and PAR1 deficient mice. Additionally, we found that BM LTR-HSC functionally express the metalloproteinase TACE (ADAM17) on the cell membrane, and that in- vitro inhibition of TACE activity by a newly developed selective inhibitor, reduces thrombin- mediated EPCR shedding, suggesting the involvement of TACE in EPCR shedding and HSC mobilization. Moreover, EPCR shedding was also CXCR4 dependent, revealing a crosstalk between EPCR, PAR1 and CXCR4. HSPC mobilized by thrombin possessed increased long-term repopulation capability following transplantation into lethally irradiated recipient mice and re-synthesis of EPCR by donor HSC in the engrafted host BM. In addition, EPCR expression was re-induced on circulating stem cells following in vitro treatment with eNOS inhibitor. Interestingly, bypassing eNOS by directly injecting NO donor, induced EPCR shedding, CXCR4 upregulation and rapid HSPC mobilization in both wild type and eNOS KO mice. Importantly, we found that similar to mice, EPCR was selectively and highly expressed by primitive human BM CD34+CD38- HSC, but not in the blood circulation of clinical G-CSF mobilized stem cells or in motile cord blood stem cells. Human BM CD34+/CD38- HSC are functionally EPCRhigh cells, maintaining low levels of intracellular NO which mediates their increased adhesion, while EPCR shedding was important for their migration and mobilization. In the functional pre-clinical NOD/SCID mouse model, G-CSF mobilization induced EPCR shedding, up-regulation of PAR1 and CXCR4 on human stem and progenitor cells, while NO signaling inhibition blocked G-CSF induced mobilization and increased both murine and human EPCRhigh stem cell accumulation in the murine BM.Our results define functional roles for EPCR, on both human and murine HSC, and suggest that regulation of EPCR expression is linked to NO, PAR1 and CXCR4 signaling as a pivotal mechanism determining HSC localization and function. Our study reveals that activation of coagulation in the context of cell injury controls stem cells retention and motility, and suggests that targeting this system may be useful in improving clinical stem cell mobilization and transplantation protocols. Disclosures:No relevant conflicts of interest to declare.

High Progression-Free Survival At 10 Years After Tandem Autologous/Nonmyeloablative Allogeneic Transplants For Multiple Myeloma In a Cohort Of 93 Patients: Impact Of Disease Remission Status At Transplant and Chronic Graft-Versus-Host Disease

IntroductionDespite improved survival with new molecules, allogeneic hematopoietic stem cell transplantation (alloHSCT) remains the only curative option for multiple myeloma (MM). Myeloablation with autologous HSCT (autoHSCT) followed by nonmyeloablative (NMA) alloHSCT has reduced the high nonrelapse mortality (NRM) rates associated with myeloablative alloHSCT, but randomized trials comparing NMA alloHSCT with standard therapy have yielded conflicting results. Factors affecting long-term outcomes have not been clearly defined. We sought to identify factors associated with outcomes in a large single-center cohort of 93 tandem transplant recipients. MethodsWe conducted a prospective phase II trial in Durie-Salmon (DS) stage II/III newly diagnosed MM patients <65 years with a 6/6 sibling donor, characterized by outpatient alloHSCT and complete immunosuppression withdrawal by day +100. Following induction therapy, patients received autoHSCT followed 3 months later by an outpatient NMA alloHSCT. Conditioning regimen consisted of fludarabine (30 mg/m2 x 5 days) and cyclophosphamide (300 mg/m2 x 5 days), followed by donor G-CSF mobilized stem cells (target dose: ≥4 x 10^6 CD34+/kg). GVHD prophylaxis included tacrolimus (day -10 to +50, taper by +100) and mycophenolate mofetil 1000 mg BID (day +1 to +50). Probabilities of overall and progression-free survival (OS and PFS), relapse, NRM and graft-versus-host disease (GVHD) incidences were estimated taking competing risks into account when appropriate. Regression analysis using Cox and Fine & Gray models were used to determine factors influencing outcomes. Severity of chronic GVHD was assessed by the proportion of alive patients on systemic immunosuppression. ResultsFrom 2001 to 2010, 93 patients received tandem HSCT from a matched sibling donor; median age was 52 years (range 39-64) and DS stage III present in 76%. All but 6 patients received a single line of induction therapy. Median time from diagnosis to autoHSCT and from auto- to alloHSCT were 7 (range 3-57) and 4 (range 2-13) months, respectively. At least partial remission (PR) status was obtained in 84% patients before tandem HSCT. After a median follow-up of 7 years, cumulative incidences of grade II-IV acute and extensive chronic GVHD were 9% (95%CI: 4-15) and 85% (75-91) respectively. Cumulative incidences of NRM and progression were 10% (95%CI: 3-22) and 47% (37-58; Fig. 1). Probability of 10-year OS and PFS were 64% (50-74; Fig. 2) and 44% (31-56; Fig. 1) respectively. In multivariate analysis, at least stable disease (SD) status before alloHSCT was a significant protective factor for progression incidence and PFS (respectively, HR 0.18, CI: 0.05-0.64, and HR 0.12, CI: 0.04-0.36). Extensive chronic GVHD as time-dependent variable was also protective for PFS (HR 0.39, CI: 0.19-0.80). The most significant protective factor for OS was at least SD status before alloHSCT (HR 0.15, CI: 0.04-0.56). The association between chronic GVHD and OS did not reach statistical significance. In survivors, the probability of being on systemic immunosuppressive treatment for GVHD was 39% (CI: 27-52) at 5 years and 15% (CI: 4-42) at 10 years. [Display omitted] [Display omitted] ConclusionsWe report a very high PFS of 44% at 10 years in a large cohort of 93 NMA alloHSCT recipients. Despite the high incidence of chronic GVHD, we observed a low NRM of 10% and an acceptable prevalence of immunosuppressive therapy of 15% at 10 years. Chronic extensive GVHD and achievement of disease control before HSCT were both associated with better PFS. Patients with progressive disease do not seem to benefit from NMA alloHSCT and efforts to reduce chronic Disclosures:No relevant conflicts of interest to declare.

Intermediate-dose Ara-C plus G-CSF for stem cell mobilization in patients with lymphoid malignancies, including predicted poor mobilizers

The optimal protocol for mobilization of hematopoietic stem cells in patients with lymphoid malignancies has not been determined so far. We retrospectively analyzed the efficacy and safety of Ara-C at a dose of 1.6 g/m(2) compared with CY at a dose of 4.0 g/m(2), both combined with filgrastim. Seventy and forty-five patients, respectively, were included, among whom 60% were defined as 'predicted poor mobilizers'. The use of Ara-C was associated with significantly higher peak number of circulating CD34(+) cells compared with CY (P<0.0001). In the Ara-C group, 95% of patients with multiple myeloma (MM) collected at least 5 × 10(6) CD34(+) cells/kg required for tandem transplantation, and 97% of lymphoma patients collected at least 2 × 10(6) CD34(+) cells/kg, needed for a single autologous hematopoietic SCT (autoHSCT), which was achieved with a single leukapheresis in 91% of cases. Results for the CY group were significantly inferior (P<0.0001). No patient mobilized with Ara-C experienced febrile neutropenia, whereas 35% required platelet transfusions. Among patients who proceeded to autoHSCT, the time of both neutrophil and platelet recovery was significantly shorter for those mobilized with Ara-C than CY. We conclude that intermediate-dose Ara-C+filgrastim is a very effective and relatively safe mobilization protocol for patients with lymphoid malignancies.