CD34 Cell Dose Research Articles

Autologous Stem Cell Transplantation Achieves Long-Term Survival in a Selected CNS Lymphoma Population

Despite recent advances in care, central nervous system (CNS) lymphoma remains a disease with very poor long-term outcomes. We reviewed outcomes at our centre following the adoption of autologous stem cell transplant (ASCT) for patients achieving remission.Records for 78 consecutive unselected patients diagnosed with cerebral diffuse large B-cell lymphoma (DLBCL) between 2003-2014 were analyzed. 62 of these patients did not undergo ASCT. The median age for the non-ASCT group was 60 years (range 26-80, 32 males, 30 females). Of these 50 had primary CNS lymphoma (PCNSL) and 12 cases had isolated CNS relapse after systemic lymphoma. 5 patients were HIV positive, and 4 patients had post-transplant lymphoproliferative disease. 30 patients received HD-MTX alone and 3 patients received whole brain radiotherapy (WBRT) alone. 10 patients received HD-MTX with salvage WBRT on relapse and 1 patient with CNS relapse post BEAM autograft for systemic disease received HD-MTX & WBRT. 14 patients received palliative treatment and 2 unknown.The remaining 16 DLBCL patients and an additional 3 with mantle cell (2) or ALK positive anaplastic lymphoma (median age 53, range 27-67, male: female 13:6) who were in remission (VGPR/CR) by MRI with adequate performance status (PS) underwent ASCT after HD-MTX-based induction therapy, conditioned with 400mg/m2 BCNU & 10mg/kg Thiotepa. 4 received WBRT post-ASCT as adjuvant therapy. Of the 19 ASCT patients 16 presented with PCNSL, 2 late relapses confined to the CNS following prior systemic DLBCL, 1 mantle cell showed evidence of low-level disease on bone marrow biopsy and all were HIV negative.Median CD34 cell dose was 4.48 x 106. Median times to neutrophil and platelet engraftment were 12 (range 10-57) and 15.5 (range 7-57) days respectively. No deaths occurred from transplant-related complications, including sepsis. 2 year PFS was 67% and OS was 73%. 4 patients relapsed post-transplant (21%), all within 4 months of transplant; 3 subsequently died. 1 patient developed systemic disease progression at time of ASCT and 1 had evidence of a mixed response on MRI pre-ASCT. No patients in CR pre-ASCT have relapsed and 1/11 PR patients has relapsed. The longest remission is now 64 months without use of WBRT, providing evidence for durable long-term response and possible cure in an unselected group of patients.For the non-ASCT patients, median OS post diagnosis was 2.5 months overall, and 7.5 months, excluding palliative patient. Of those receiving MTX therapy 7 achieved CR, 7 PR and 23 had PD. 3 patients failed to tolerate treatment. Of those who achieved CR/PR reasons for not proceeding to ASCT included inadequate PS or lack of willingness to receive further therapy. Outcomes for those who achieve CR are good, with median PFS & OS for patients achieving CR not reached at a median of 32 months follow-up. 5/7 remain in remission; 1 patient has died. Only 1 of these patients received WBRT. The median PFS & OS for patients achieving PR were 5.5 & 8 months respectively (p= 0.041 & 0.027 vs CR).When comparing the two groups, median OS for patients receiving ASCT was not reached vs 5 months for MTX alone (p<0.001) and 29 months for MTX & WBRT (p=0.013).Overall we conclude MTX therapy alone induces CR in only a small number of patients and outcomes for those not achieving CR are dismal. For patients who are able to proceed to ASCT long-term remissions can be obtained. New strategies are required to enable patients to achieve CR in order to receive ASCT and thus achieve a durable long-term survival from CNS lymphoma. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Allogeneic Hematopoietic Stem Transplantation in Patients with Transfusion Dependent Beta Thalassemia: A Single-Center Experience from India

Introduction:The thalassemias are the most common of the inherited abnormalities of hemoglobin, typically characterized by a quantitative defect in the synthesis of either the alpha or beta globin chain, resulting in reduced or absent synthesis of either of the globin chains followed by ineffective erythropoiesis with hemolysis. Beta thalassemia is prevalent in the populations of the Mediterranean region, the Middle East, India, Pakistan, and Southeast Asia.Patients are treated with red blood cell transfusions and iron chelation to prevent organ iron overload. Currently, the only cure for thalassemia is allogeneic bone marrow transplantation which corrects the genetic defect in the hematopoietic system by the use of allogeneic stem cells.Methods:We retrospectively and prospectively analyzed the outcomes in transfusion dependant beta Thalassemia patients, who underwent allogeneic HSCT between June 2004 and June 2014. The patients were classified into Class 1, 2 and 3 as per the Pesaro criteria.Results:Sixty seven patients (Males n=40; females n=27) with a median age of 7 years (range 2 to 22 years) underwent HSCT during this time. Fifty seven patients were classified as Class 2, 8 as Class 3 and 2 as Class 1. The conditioning regimens used consisted of Bu-Cy-ATG (n=30), Bu-Cy (n=2), Flu-Bu-Cy-ATG (n=23), Treo-Flu-Thio (n=8), Treo-Flu-Thio-ATG(n=3) and Flu-Bu-Cy-Thio-ATG(n=1) with cyclosporine and methotrexate as GVHD prophylaxis. Stem cell source was marrow, peripheral stem cells and cord in 50, 17 and 1 patients respectively. Sixty four patients had matched sibling transplant and three non-sibling donors (one unrelated cord, one matched unrelated and one haplo-identical ). One patient received both both marrow as well as peripheral stem cells. The median TC cell dose was 6.4x108/kg (range 3 to 16.3 x108/kg) and median CD34 cell dose of 2.4 x106/kg (range 0.6 to 19.6 x106/kg). Hematological recovery was seen in all patients except three patients, who died before engraftment. Neutrophil and platelet engraftment occurred at a median of 14 days (range, 10-22 days) and 22 days (range, 10-35 days), respectively. Twenty four patients developed veno-occlusive disease, 20 patients developed Gr II-IV acute graft-versus-host disease (GVHD), and 3 patients had chronic GVHD. At day +28, thirty five patients showed more than 90% donor chimersim and rest had mixed chimerism. Four patients experienced graft rejection. Treatment-related mortality (TRM) for the whole cohort was 10.4% at 100 days and 14.9% at 6 months post transplant. TRM was 12.28% and 37.5% for Class 2 and class 3 patients respectively. At a median follow up of 416 days, overall survival and thalassemia free survival are 82.1%, and 74.6% respectively.Conclusion: Similar outcomes have been reported from developed countries. Outcome of Class 3 patients still continues to be poor and VOD rates are high in this patient group. DisclosuresNo relevant conflicts of interest to declare.

Pre-Transplant Consolidation and Cost Effectiveness of RIC Allogeneic SCT in Patients of AML-CR1 in India

▪Management of acute myeloid leukemia (AML) in India remains a challenge. A major constraint is the cost of therapy. In a predominantly self paying system the majority of patients will not have the resources to manage a subsequent relapse. Hence, the choice of consolidation therapy has to be carefully considered to balance cost and efficacy. An allogeneic SCT (alloSCT) with a reduced intensity conditioning regimen (RIC) in first remission (CR1) is an attractive option to fulfill these requirements of relatively low cost without compromising efficacy. The need for consolidation chemotherapy prior to offering a RIC alloSCT for AML CR1 remains controversial. To evaluate these aspects we undertook a retrospective analysis of patients with AML CR1 who received a RIC alloSCT from multiple centers in India. Conventional criteria were used for definition of conditioning regimens to be considered RIC (CIBMTR).Data from 8 centers in India was collected between 2005 and 2013. A total of 138 patients fulfilled the criteria of AML CR1 having received an alloSCT with a RIC regimen. The median age was 34 years (range: 2 – 63) and 60% were males. The median time from diagnosis of AML to transplant was 99 days (range: 41 – 504). 123 (89%) were HLA matched related donors, 3 (2.1%) were MUD transplants and the rest were HLA mismatched related donors. The majority by cytogenetics (n=115) were intermediate risk (76%) followed by high risk (23%). 70 (51%) received chemotherapy consolidation prior to transplant, 61 (44%) did not and data was not available in 7 (5%). 68% of those that received consolidation received intermediate or low dose cytosine based regimens. 129 (94%) were CMV serology positive pre-transplant. Fludarabine with melphalan (140mg/m2) (128{93%}) was the most commonly used regimen and cyclosporine with short course low dose methotrexate (126{91%}) the most commonly used GVHD prophylaxis regime. All patients received a PBSC graft with a median CD34 cell dose of 9.1x106/kg (range: 1.3 – 43). With the exception of one, all patients engrafted. The median time to ANC >500/mm3 was 13 days (range: 7 – 22) and platelet count of >20,000/mm3 was 15 days (range: 0-33). Of those that engrafted, 97% achieved complete chimerism at one month post transplant (data not available in 4). Post transplant CMV reactivation was seen in 32% and a fungal infection (possible, probable or definitive) in 13%. Acute GVHD Grade 2-4 was seen in 29% and of patients evaluated 62% had chronic GVHD, the majority of these being limited (61%). The 100 day treatment related mortality (TRM) was 7.5% and the one year TRM was 25.6%. At a median follow up of 24 months the 5 year EFS and OS was 64.0±5.07 (Figure 1A) and 71.1±4.0 respectively. The 5 year cumulative incidence of relapse was 21.8% (Figure 1A). The baseline characteristics as mentioned above were not significantly different between the group that received consolidation and the group that did not. The use of consolidation therapy prior to alloSCT did not have a significant impact on EFS or OS (Figure 1B).On univariate analysis the factors that adversely impacted EFS were mismatched non sibling family donor (RR 8.1; P-value 0.001), CMV reactivation (RR 2.6; P-value 0.001), fungal infection post transplant (RR 6.8; P-value 0.000) and acute GVHD (RR 2.1; P-value 0.02). On a forward stepwise multivariate analysis adjusting for these and other conventional risk factors only CMV reactivation (RR 2.0; 95% CI 1.03-3.87; P-value 0.042) and fungal infection (RR 7.1; 95%CI 3.154-16.12; P-value 0.000) retained their adverse impact. There was no correlation between CMV reactivation and relapse of disease post transplant.The mean costs of induction chemotherapy for these patients was US$ 9239±3596 (n=74), for consolidation chemotherapy it was 5007±3490 (n=21) and for alloSCT it was 18138±13826 (n=118; costing up to 1 year post transplant). Induction chemotherapy followed by HLA matched RIC alloSCT is likely to be a cost effective and affordable treatment option for young adults with AML in CR1in an Indian context. With an average gross net income in India of US$3500/year (http://indiabudget.nic.in) the limitation still remains the cost of treatment and number of centers that can offer this therapy. [Display omitted] DisclosuresSrivastava:Octapharma: Consultancy, Other. Off Label Use: Bortezomib in the treatment of acute promyelocytic leukemia.

Improved Outcomes of Autologous Hematopoietic Cell Transplantation (AHCT) for Light Chain (AL) Amyloidosis: A Center for International Blood and Marrow Transplant Registry (CIBMTR) Study

Background: Light chain (AL) amyloidosis is a rare plasma cell neoplasm associated with systemic amyloid deposition leading to organ dysfunction and death without treatment. The use of AHCT in AL amyloidosis remains controversial as a prospective randomized control trial suggested inferior outcomes when compared with standard chemotherapy, driven primarily by high peri-transplant mortality (TRM) up to 24%. Improved patient selection criteria, supportive care and risk-adapted therapy have reduced TRM in recent single center studies. We analyzed trends and prognostic factors associated with AHCT outcomes in AL amyloidosis patients.Methods: We identified 1532 AL amyloidosis patients who underwent AHCT following high dose melphalan (MEL) within 24 months of diagnosis between 1995 and 2012 from the CIBMTR database. A subset of patients with more complete level of research data reported between 2001 and 2012 was analyzed for multivariate analysis (n=354). The primary endpoints were day30 and day100 mortality, hematologic progression free survival (PFS), hematologic relapse/progression and overall survival (OS). Data regarding cardiac, renal, hepatic and neurologic amyloid involvement was collected. Hematologic and organ response and progression were defined based on the 2004 uniform consensus criteria.Results: The median age at transplant was 57 years, with 61% males. AHCT was performed within 6 months of diagnosis in 66% patients. Karnofsky performance score (KPS) was <80 in 14%, HCT-CI was ≥ 3 in 20% and 69% had a lambda isotype. Organ involvement included renal, cardiac, hepatic and autonomic nervous system involvement in 74%, 38%, 16% and 11% respectively. Coexistent myeloma (>10% bone marrow plasma cells) was seen in 14%. Progressively higher numbers of patients received AHCT from 1995-2000 (n=140) to 2001-2006 (n=595) and 2007-2012 (n=800). The majority were untreated pre-transplant (77%) while 8% received melphalan, 6% thalidomide and 4% each received lenalidomide and bortezomib based pre-AHCT therapy. The median CD34 cell dose infused was 4.4 X 106/kg cells (IQR 3.3-6.2). MEL dose reduction was common (60% received < MEL 180 mg/m2 and 38% < MEL 140 mg/m2). The median length of hospital stay was 17 days (IQR 13-23). The median follow-up of patients from the time of transplant was 61 months (range 3-145). Day100 response included hematologic complete response, CR (12%), partial response, PR (26%), stable disease, SD (23%), and renal response (12%) with an ultimate best response of hematologic CR (33%), PR (28%), SD (19%) and renal response in 31%. Table 1 shows day30 and day100 mortality and OS at 1, 3 and 5 years showing steady declines in mortality rates and improvements in survival in successive time cohorts. Figure 1 shows the 5 year OS in each of the time cohorts. On multivariate analysis, albumin ≥ 3 g/dl at diagnosis, KPS ≥80, pre-transplant anti-plasma cell therapy and MEL ≥180 mg/m2 were associated with lower hematologic relapse/progression. KPS ≥80 and predominant renal involvement were associated with superior hematologic PFS while KPS ≥80 and < 2 organ involvement correlated with OS.Table 1Outcomes of AHCT in AL amyloidosis. Values are expressed as probabilities with 95% confidence intervals.1995-2000 N=1402001-2006 N=5952007-2012 N=800Day 30 mortality11 (7-17)5 (4-7)3 (2-4)Day 100 mortality20 (14-27)11 (8-13)5 (4-7)1 year survival75 (67-82)85 (81-87)90 (88-92)3 year survival64 (56-72)72 (68-75)83 (80-86)5 year survival55 (46-63)61 (57-65)77 (72-82)Conclusions: There has been a significant improvement in survival of AL patients after AHCT driven primarily by a reduction in early peri-transplant mortality. Limited organ involvement, higher KPS, use of pre-transplant therapy and higher dose melphalan conditioning contributed to superior outcomes. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

A Phase 2 Study of High-Dose Melphalan Plus Bortezomib (Mel/Vel) Conditioning Followed By Autologous Hematopoietic Cell Transplantation in Myeloma

Background:High-dose melphalan followed by autologous hematopoietic cell transplantation (HCT) remains the integral component of multiple myeloma (MM) therapy in the era of novel agents. We published our prior study with the use of high-dose melphalan + bortezomib (Mel/Vel) conditioning regimen for tandem transplants in refractory MM patients (Nishihori, et al. Br J Haematol 2012). We designed a phase 2 trial using MelVel conditioning followed by autologous HCT in patients with newly diagnosed chemosensitive MM (NCT 00948922).Methods:Sixty seven newly diagnosed MM patients who achieved ≥ partial response (PR) to induction therapy with ≤grade 1 peripheral neuropathy (PN) were enrolled from 12/2009 to 06/2014. Patients received high-dose melphalan at 100 mg/m2 IV for 2 days, immediately followed by 1 dose of bortezomib at 1.3 mg/m2 (Mel/Vel conditioning). Maintenance therapy was not prescribed by design. The protocol later was modified to include maintenance bortezomib subcutaneously (started at 3 months after HCT) at 1.3 mg/m2 weekly x4, every 8 weeks, for a total of 6 cycles. Progression-free and overall survival (PFS and OS) estimates were calculated using Kaplan-Meier method.Results:A total of 67 patients received autologous HCT. The median age was 58 (25 - 73) years with the following disease characteristics: Durie-Salmon stage, 3A (72%) and 3B (10%); IgG (55%), IgA (21%), IgD (1%), and light chain (22%). High-risk cytogenetics/FISH were seen in 28% of patients. The median beta-2 microglobulin was 3.3 (range, 1.3 – 34.8). Induction regimens were bortezomib-based in 39%, lenalidomide-based in 19% and, both bortezomib and lenalidomide in 42%. Median time from initiation of induction to HCT was 204 days (range, 101 - 664). Responses prior to HCT were stringent CR (sCR) 21%, CR 12%, very good partial response (VGPR) 34%, and PR 33%. Neutrophil engraftment was achieved after a median of 11 days (range, 10 – 14) and platelet engraftment occurred after a median of 15 days (range, 11 – 22). Median CD34 cell dose was 3.8 x 106/kg (range, 2 – 20.08). Responses at 3 months after HCT (in 64 evaluable patients) were sCR 47%, CR 14%, VGPR 20%, PR 16% and progressive disease 3%. Bortezomib maintenance was prescribed to 31 patients (46%). Prevalence of grade 1 PN before (n=67) and at 3 months (n=64) after HCT were 37% and 38%, respectively. Two patients withdrew consent to initiate maintenance and 1 patient was unable to initiate maintenance due to grade 1 PN (baseline PN of 0). At the time of review, a median number of maintenance delivered was 4 (range, 1-6) and only one patient required dose reduction. The 2-year PFS and OS estimates are 62% (95% CI 0.47 – 0.75) and 90% (95% CI 0.80 – 0.97) with a median follow-up of 21 months (range, 2 – 54). The 1-year PFS estimates were 85% (95% CI 0.65 – 0.97) for bortezomib maintenance vs. 81% (95% CI 0.66 – 0.92) for no maintenance (p=0.6). There were no significant differences in PFS or OS stratified by cytogenetic/FISH risk status. There was no transplant related mortality.Conclusions:The combination of bortezomib and high-dose melphalan (Mel/Vel) as conditioning regimen for autologous HCT is well tolerated and appears to improve responses after HCT. Weekly x4 post HCT bortezomib maintenance given every 8 weeks appears to be well tolerated and is a promising strategy for eligible patients. Longer follow up is required to assess the benefit of post HCT maintenance strategy. DisclosuresBaz:Millennium: Research Funding. Alsina:Millennium: Consultancy, Research Funding.

Microtransplantation: HLA-Mismatched Allogeneic Cellular Therapy of Acute Myeloid Leukemia (HMMACT)

Background: This clinical trial addressed feasibility and safety of microtransplantation by HLA-mismatched allogeneic cellular therapy (HMMACT) in poor risk acute myeloid leukemia patients. A secondary objective was to estimate complete response rate, infections, GVHD incidence, and induction mortality.Methods: Patients with high risk AML were enrolled: 4 were > 75 yo, 3 with MLL+ ((t(6;11), 11+ and t(10;11)), 3 complex/del7, one FLT3+. Patients received induction chemotherapy with mitoxantrone (10 mg/m2 IV for 3 days) and cytarabine (150 mg/m2 IV for 7 days) and received HLA-mismatched GCSF mobilized PBSCs on day 9 or 10. Family donors were concurrently HLA typed and best available donor underwent GCSF mobilization (5 mg/kg SQ BID x 4 days) and leukapheresis after medical evaluation and safety testing. HLA partial mismatch patients (4- 5/10 antigen) were chosen. Apheresis cells were counted and analyzed by flow cytometry for CD34+ cells; CD3+, CD4+CD25+ and CD8 + cells; and CD3-CD56+ NK cells. Target CD3 cell dose was 1 x 108/kg per cycle; cells cryopreserved as for standard stem cell donors. Family donor HLA-mismatched GCSF mobilized peripheral blood cells were infused fresh on day 9 or 10 (up to day 16), 36-50 hours after end of cytarabine. Bone marrow biopsy was evaluated on day 14 and 28 for AML remission status, and T/NK cell number. Patients achieving a complete response proceeded to consolidation with cytarabine 0.5 -1.0 gram/m2 x 6 doses with fresh or cryopreserved HMMACT cells from their donor for 2 courses a month apart. Patients: 10 patients age 31 – 80 yo consented: 8 received allo cells; 1 screen failure (no haplo family member identified); 1 patient too ill after initiating chemo to collect donor. Eight patients received at least one course of HMMACT; 1 withdrew early due to AML progression, a second for poor performance status. Three patients had de novo AML; 5 patients had secondary AML. Six Patients had2 or more cycles of HMMACT: four achieved CR: Pt 1 and 4 received 3 cycles, Pt 2 and 6 received 2 cycles of cell infusions and all achieved CR. Pt 9 received 2 inductions with cells, and sustained a partial clinical remission for 6 months. Two Patients had 1 cycle of HMMACT:Pt 3: received 1 cycle cells, but response not assessed; Pt 8: received 1 cycle cells, and achieved CR 3+mos but declined further therapy. Safety: Acute reactions to cell infusions were minimal. Delayed reactions attributed to cell infusions included fever grade 1-2, rash grade 1-2, diarrhea grade 1-2 resolving in 7-10 days. Patients with prior MDS or refractory leukemia requiring 2 inductions had a longer time to ANC and platelet recovery. Feasibility: Two patients had no donor; 2 donors only collected enough for 2 cell infusions. Response: 5/8 pts receiving cells had CR/CRi (62.5%) lasting 3 to 10+ months.Conclusions: Although there were the usual significant complications of treating leukemia and infections, the cellular therapy itself was well-tolerated. Patients often had fevers in first week after cell infusions, or experienced transient rash and diarrhea in the same time period, which were self resolving in all cases and may reflect elimination of allogeneic cells by the patient’s immune system. No patient developed GVHD. Feasibility of obtaining family donors was as expected for this diverse US population. Infectious complications were low by AML treatment standards. Complete remission rates are encouraging, but not as durable as hoped, likely reflecting the fact that all of our patients had high risk cytogenetics in contrast to the prior published studies by Chinese investigators. The majority were elderly who would not otherwise be offered intensive therapy. Family donors achieved expected cell targets and tolerated mobilization/collection procedures well. All but one patient receiving 2 to 3 cycles achieved complete remission. Two elderly patients who received one or two cell infusions during induction sustained prolonged survival of 6 months in spite of no further therapy, one achieving a CR and the other a sustained PR. Neutrophil and platelet recoveries tended to follow the pattern of the patient’s prior secondary leukemia or myelodysplastic disorder. Once patients achieved complete remission however, recovery of blood counts was relatively rapid on further cycles of consolidation. We are now assessing Treg, T and NK cell phenotype of patient and donor cells by flow cyAtometry as biological correlates. DisclosuresChaudhary:University of Southern California: Inventor on a patent application relevant to this work filed to US patent office (No. 62/031,053). Patents & Royalties.

Using algorithms to standardize peripheral stem cell mobilization and collection.

233 Background: Review of peripheral stem cell (PSC) collection data showed a significant practice variation in the number of collections, minimum and target dose of PSC collected, and the use of plerixafor for mobilization of PSC. In addition, the peripheral blood CD34 test was not used to determine the start of collections. At this institution, approximately 100 adult patients collect PSC per year with a mean of 3 (range 1-10) collections per patient. Cost per patient varied from $9,800 to $74,600. Methods: Patients planned to undergo an autologous PSC transplant, 18 years and older, were included. Three years of historical data was analyzed and pilot algorithms developed. Algorithms identified when to start and stop collecting, if and when to start plerixafor, and when to re-evaluate the mobilization method. The use of the peripheral blood CD34 test was implemented. The minimum CD34 cell dose was standardized and the target dose was lowered. The entire collection process was reviewed and additional efficiencies were identified. Results: Analysis of 42 patients’ collections January 2013 through July 2013 revealed that the majority of patients (86%, n=36) were able to achieve the target CD34 dose in 3 or fewer collections (mean = 1.5, range = 1-4). The algorithms were followed in 41/42 patients. The patients’ engraftment and length of stay were similar to historical data suggesting that the minimum and target CD34 dose is acceptable. Work flow changes associated with the use of the peripheral CD34 test didn’t produce any negative impact on the departments involved. The initial collection cost decreased by approximately $2,000 and each additional collection decreased by approximately $800. The average cost savings per patient was $9,500. The actual total cost savings over a six month period was $303,204. The mean total number of collections per patient decreased from 3 to 1.5. Conclusions: Standardization of practice can result in significant cost savings. Using an expensive drug (plerixafor) in well-defined situations makes good clinical and economic sense. Reviewing processes also identifies additional opportunities in which to make positive changes.

CD34(+) cell therapy is safe and effective in slowing the decline of hepatic reserve function in patients with decompensated liver cirrhosis.

Preclinical studies in rodent models of chronic liver fibrosis have shown that transplantation of peripheral blood (PB) CD34(+) cells leads to hepatic regeneration and a reduction of liver fibrosis by suppressing hepatic stellate cell activity and increasing matrix metalloproteinase activity. The aim of this study was to examine the safety and clinical efficacy of intrahepatic transplantation of autologous granulocyte colony-stimulating factor (G-CSF)-mobilized PB-CD34(+) cells in patients with decompensated liver cirrhosis. PB-CD34(+) cells were isolated from G-CSF-mobilized apheresis products. Ten patients were treated with G-CSF-mobilized PB-CD34(+) cells (treatment group) and seven patients were treated with standard medical therapy. For mobilization, patients in the treatment group received subcutaneous injections of 10 μg G-CSF/kg/day for 5 days. The cells were then injected at three different doses (5 × 10(5) , 1 × 10(6) and 2 × 10(6) cells/kg) through the hepatic artery. Thereafter, all patients were followed up for 24 months. G-CSF treatment and leukapheresis were well tolerated, and no serious adverse events were observed. Patients in the treatment group had a significant but transient splenomegaly. After 24 weeks, serum albumin was significantly increased in patients who had received middle or high doses of CD34(+) cells compared with baseline. Doppler ultrasound showed a significant increase in hepatic blood flow velocity and blood flow volume after CD34(+) cell therapy. The hepatic vein pressure gradient decreased in two patients who received high-dose CD34(+) cells at week 16. CD34(+) cell therapy is feasible, safe and effective in slowing the decline of hepatic reserve function.

Human herpesvirus 6 reactivation before engraftment is strongly predictive of graft failure after double umbilical cord blood allogeneic stem cell transplantation in adults

Our main objective was to determine new factors associated with engraftment and single-unit predominance after double umbilical cord blood (UCB) allogeneic stem-cell transplantation. Engraftment occurred in 78% of cases in this retrospective study including 77 adult patients. Three-year overall survival, disease-free survival, relapse incidence, and nonrelapse mortality were 55 ± 6%, 44 ± 6%, 33 ± 5%, and 23 ± 4%, respectively. In multivariate analysis, Human herpesvirus 6 reactivation during aplasia (hazard ratio [HR] = 2.63; 95% confidence interval [CI]: 1.64-4.17; p < 0.001), younger recipient age (<53 years) (HR = 1.97; 95% CI: 1.16-3.35; p = 0.012), and lower human leukocyte antigen matching between the two units (3 of 6 or 4 of 6) (HR = 2.09; 95% confidence interval: 1.22-3.59; p = 0.013) were the three factors independently associated with graft failure. Also, factors independently predicting the losing UCB unit were younger age of the UCB unit (odds ratio [OR] = 1.01; 95% CI: 1-1.02; p = 0.035), lower CD34(+) cell dose contained in the UCB unit (≤ 0.8 × 10(5)/kg) (OR = 2.55; 95% CI: 1.05-6.16; p = 0.04), and presence of an ABO incompatibility between the UCB unit and the recipient (OR = 2.53; 95% CI: 1.15-5.53; p = 0.02). Thus, Human herpesvirus 6 reactivation during aplasia, lower unit-unit human leukocyte antigen matching, and younger UCB unit age, as new unfavorable predictive factors, may represent new parameters to take into account after double UCB allogeneic stem-cell transplantation in adults. These results need to be confirmed prospectively, as they may influence unit selections and patient outcomes.

Factors predicting haematopoietic recovery in patients undergoing autologous transplantation: 11-year experience from a single centre.

Engraftment outcomes following autologous transplantation correlate poorly to infused stem cell number. We evaluated 446 consecutive patients who underwent autologous transplantation at our centre between 2001 and 2012. The impact of pre-transplant and collection factors together with CD34(+) dosing ranges on engraftment, hospital length of stay (LOS) and survival endpoints were assessed in order to identify factors which might be optimized to improve outcomes for patients undergoing autologous transplantation using haemopoietic progenitor cells-apheresis (HPC-A). Infused CD34(+) cell dose correlated to platelet but not neutrophil recovery. Time to platelet engraftment was significantly delayed in those receiving low versus medium or high CD34(+) doses. Non-remission status was associated with slower neutrophil and platelet recovery. Increasing neutrophil contamination of HPC-A was strongly associated with slower neutrophil recovery with infused neutrophil dose/kg recipient body weight ≥3 × 10(8)/kg having a significant impact on time to neutrophil engraftment (p = 0.001). Higher neutrophil doses/kg in HPC-A were associated with days of granulocyte colony stimulation factor (G-CSF) use, HPC-A volumes >500 ml and higher NCC in HPC-A. High infused neutrophil dose/kg and age >65 years were associated with longer hospital LOS (p = 0.002 and 0.011 respectively). Only age, disease and disease status predicted disease-free survival (DFS) and overall survival (OS) in our cohort (p < 0.005). Non-relapse mortality was not affected by low dose of CD34(+) (<2 × 10(6)/kg). In conclusion, our study shows that CD34(+) remains a useful and convenient marker for assessing haemotopoietic stem cell content and overall engraftment capacity post-transplant. Neutrophil contamination of HPC-A appears to be a key factor delaying neutrophil recovery. Steps to minimize the degree of neutrophil contamination in HPC-A product may be associated with more rapid neutrophil engraftment and reduced hospital LOS.

Impact of uncontrolled freezing and long-term storage of peripheral blood stem cells at −80 °C on haematopoietic recovery after autologous transplantation. Report from two centres

Controlled-rate freezing and storage in vapour phase nitrogen are used by most transplantation teams for the cryopreservation and storage of peripheral blood haematopoietic stem cells (PBSC). In this study, we analysed 666 autologous PBSC transplants after uncontrolled freezing and storage of PBSC at -80 °C. Statistical analysis showed that neutrophil recovery was associated with both the infused CD34(+) cell dose (P=0.01) and the post transplantation use of growth factors (P<0.001) and that platelet recovery was associated with the infused CD34(+) cell dose (P<0.001) and with the diagnosis (P=0.02). We analysed three groups according to the duration of the cryopreservation period (less than 6 months, between 6 and 12 months or more than 1 year). Haematopoietic recovery was not found to be adversely affected by longer storage at -80 °C. The haematopoietic recoveries of 50 pairs of sequential transplantations from the same PBSC mobilization were analysed. Despite prolonged cryopreservation, there were no statistically significant differences in neutrophil (P=0.09) or platelet (P=0.22) recovery in the second compared with the first transplant. In conclusion, the long-term storage of PBSC at -80 °C after uncontrolled-rate freezing is an easy and comparatively inexpensive cryopreservation method that leads to successful haematopoietic recovery even after prolonged storage.

Pre infusion, post thaw CD34+ peripheral blood stem cell enumeration as a predictor of haematopoietic engraftment in autologous haematopoietic cell transplantation

By convention, peripheral blood stem cell products for autologous transplantation are evaluated for quality by CD34(+) cell dose at the time of harvesting. A CD34(+) cell dose in excess of 2.0 × 10(6)/kg of recipient body weight is considered adequate for haematopoietic engraftment. Viable CD34(+) cell numbers are enumerated in most laboratories using the ISHAGE single platform flow cytometric method which utilizes monoclonal antibodies to CD45, CD34 and 7 amino actinomycin D (7AAD) dye exclusion. One hundred and six consecutive autologous transplantation procedures underwent viable CD34(+) cell enumeration at the time of harvesting and post thaw prior to re-infusion. Neutrophil and platelet engraftment and markers of haematopoietic support were analyzed. Mean pre-cryopreservation viable CD34(+) numbers were 4.882 × 10(6)/kg. Mean post thaw viable CD34(+) numbers were 3.234 × 10(6)/kg. Mean loss of viable CD34(+) cells with processing and cryo-preservation was 1.648 × 10(6)/kg (33%). For neutrophil engraftment, there was no significant difference between high (⩾ 3.0 × 10(6)/kg) and low (<1.5 × 10(6)/kg) post thaw viable CD34(+) cell counts (p=0.545). For platelet engraftment, there was however a significant difference observed between the high and low pre infusion viable CD34(+) groups (p<0.001). Additionally, significant differences were seen between the post thaw viable CD34(+) cell count and the associated length of hospital admission, days of use of G-CSF post transplantation, use of antibiotics in the post transplantation period and transfusion support in the post transplantation period. A significant loss of viable CD34(+) cells occurs during processing, cryopreservation and thawing. Low numbers of viable CD34(+) cells infused post thaw will still result in adequate neutrophil engraftment however may delay platelet engraftment. Low viable CD34(+) cell numbers have significant effects on admission duration and use of haematopoietic supportive measures with consequent effects on healthcare resources.

The Choice of Multiple Myeloma Induction Therapy Affects the Frequency and Severity of Oral Mucositis After Melphalan-Based Autologous Stem Cell Transplantation

Mucositis is a common complication of high-dose melphalan (HDM) used before autologous stem cell transplantation (ASCT) for multiple myeloma (MM). Mucositis rates are influenced by previous chemotherapy (CT) exposure. We examined the effect of induction therapy before ASCT on ASCT mucositis rates. Patients undergoing first 200 mg/m(2) HDM ASCT were assessed. Those receiving < 200 mg/m(2), or those with previous ASCT were excluded. Patients were evaluated depending on type of induction therapy (CT, immunomodulatory drug [IMiD], or proteasome inhibitor [PI]) before ASCT. A case record review was performed and data collected on response to induction, rates of Grade 3/4 mucositis, and days of total parenteral nutrition (TPN) or parenteral opiate analgesia. One hundred twenty-eight patients with ASCT were assessed. Induction therapy was CT- (n = 62), IMiD- (n = 51), or PI-based (n = 15) therapy. Patient characteristics were overall similar, including median age, MM stage, and CD34(+) cell dose. IMiD-based therapy patients had lower rates of mucositis (33% vs. 53%; P = .03) and less opiate requirements (10% vs. 31%; P = .02) compared with those treated with CT. Rates of mucositis and opiate use in the PI group were not different to the CT cohorts (33% vs. 53%; P = .6 and 13% vs. 31%; P = .13), likely due to concurrent anthracycline exposure. TPN usage was similar (CT, 42%; IMiD, 35%; and PI, 20%), as was neutropenia duration and antibiotic usage. Patients treated with IMiD-based regimens before HDM ASCT had significantly lower rates of mucositis than those treated with CT-based therapy. There were too few patients who received PI therapy to evaluate the effect.

High CD8 Cell Doses Correlate with Reduced Relapse Risk and Improved Survival after Allogeneic Peripheral Blood Stem-Cell Transplantation with Reduced-Intensity Conditioning

High CD8 Cell Doses Correlate with Reduced Relapse Risk and Improved Survival after Allogeneic Peripheral Blood Stem-Cell Transplantation with Reduced-Intensity Conditioning

Low CD34 Cell Dose Is Associated With Higher Non-Relapse and Overall Mortality After Reduced Intensity Conditioning Hematopoietic Cell Transplantation For Acute Myeloid Leukemia and Myelodysplastic Syndrome

In allogeneic hematopoetic cell transplantation (HCT) using myeloablative conditioning, the nucleated and CD34 cell doses were found to be of importance for several outcome parameters including survival, relapse and graft- versus- host disease (GVHD). Reduced intensity conditioning (RIC) HCT is increasingly used for older patients and for younger patients with co-morbidities. Peripheral blood progenitor cells (PBPC) is the predominant graft for RIC HCT. There is no large study of the effect of CD34 cell dose in the setting of RIC transplantation. Therefore, we studied the effect of CD34 dose on 1057 patients aged 45 – 75 years with acute myeloid leukemia (AML) or myelodysplasic syndrome (MDS) who received RIC regimen HCT between 2000 and 2011. Patients received grafts from HLA-matched siblings (n = 370) or from volunteer adult unrelated donors matched at the allele-level at HLA-A, -B, -C and –DRB1 (8/8; n = 522) or mismatched at 1 HLA-locus (7/8; n = 178). All patients received peripheral blood progenitor cells (PBPC), low dose TBI regimens (200 cGy) or alkylating agent plus fludarabine containing regimens. Separate analyses were conducted for HLA-matched and unrelated donor transplants. For HLA-matched sibling transplants (AML n=301; MDS n=69), exploratory analysis identified differences in survival for CD34 dose less than 4 x 106/kg. Multivariate modeling, adjusting for performance score, disease status, cytogenetic risk and transplant period, showed transplantation of PBPC with CD34 dose < 4 x 106/kg was associated with higher risks of overall mortality (HR 1.48, p=0.008) and non-relapse mortality (HR 2.03, p=0.004) compared to transplantation of PBPC with CD34 dose ≥ 4 x 106/kg. The effect of CD34 dose was independent of the other factors associated with mortality. The likelihood of neutrophil (HR 0.76, p=0.03) and platelet recovery (HR 0.76, p=0.03) was also lower with CD34 dose < 4 x 106/kg containing PBPC grafts. CD34 dose was not associated with acute or chronic GVHD or disease recurrence. In contrast, after unrelated donor transplantation (AML n=557; MDS n=130), the effect of CD34 cell dose on mortality was marginal. Exploratory analysis identified differences in survival for CD34 dose less than 6 x 106/kg. After adjusting for age, performance score, disease status, interval from diagnosis to HCT, and HLA-match, transplantation of PBPC with CD34 dose < 6 x 106/kg was associated with marginally higher risks for overall mortality (HR 1.20, p=0.05) and non-relapse mortality (HR 1.38, p=0.02) compared to transplantation of PBPC with CD34 dose ≥ 6 x 106/kg. There were no significant differences in hematopoietic recovery, acute or chronic GVHD and disease recurrence by CD34 dose. Further, we did not identify a CD34 dose for either donor source above which acute or chronic GVHD risks were higher. In conclusion, in the setting of RIC transplants for AML and MDS, the data support optimizing PBPC collections such that the CD34 dose delivered is in excess of 4 x 106/kg for HLA-matched sibling and CD34 dose in excess of 6 x 106/kg for unrelated donor transplants. Disclosures:No relevant conflicts of interest to declare.

CD34+ Selected Cells For The Treatment Of Poor Graft Function Following Allogeneic Stem Cell Transplantation

BackgroundWe have previously defined poor graft function (PGF) as 2 or 3 cytopenic lines (Hb<10 g/dl, neutrophil count <1,0 x 10^9/L, platelet count <30 x 10^9/L), lasting for at least 2 consecutive weeks post-transplant, beyond day +14, with transfusion requirement, associated with hypoplastic-aplastic bone marrow, in the presence of complete donor chimerism and in the absence of severe GVHD and relapse (Larocca 2006). We have also shown that PGF can be treated with the infusion of donor CD34+ cells, selected from mobilized peripheral blood. (Larocca 2006) . Aim of the StudyTo update the 2006 study in 41 patients. MethodsAll 43 patients received a boost of CD34+ selected peripheral blood stem cells (PBSC) without prior conditioning and without GvHD prophylaxis. The median age of patients was 37 years (18-60y). The median number of CD34+ PBSC infused was 3.45 x106/Kg at median days of 140 days from 1st HSCT.Complete response, or tri-lineage recovery was defined as achieving Hb >10 g/dl, ANC > 1000 x109/L, platelets > 100.000 x 109/L. A partial recovery was defined as transfusion independence, without a complete hematologic recovery. The median follow up was 1245 days. ResultsTri-lineage recovery was seen in 31/41 (76%) and 3/43 patients became transfusion independent, for an overall response of 83%). The median time for complete hematological recovery from CD34+ boost infusion was 183 days.There was no influence on tri-lineage recovery of the following factors : dose of CD34 cells (</> 3.3) (78% vs 72%), nor patient age (</>35 years) 75% vs 76%, nor donor type (HLA id sib 83%, UD 79%, family mm 68%). All the patients who achieved tri-lineage recovery are alive and disease free (28/41 patients). In this cohort 13 patients died due to relapse 9/14 (64%) or GVHD 2/14 (14%) or other causes 2/14 (14%). The overall actuarial survival is 63% with a median follow up of 1245 days (94-4151 days). Interpretations and ConclusionsWe confirm that infusion of CD34+ selected PBSC is associated with a high rates of tri-lineage recovery, with low risk of acute or chronic GVHD in patients who develop poor graft function following an HSCT. Tri-lineage recovery or achieving transfusion independency have an interesting impact either on disease free and overall survival.▪ Disclosures:No relevant conflicts of interest to declare.

Successful Engraftment In Children With Severe Aplastic Anemia After Transplantation Of HLA-Identical Hematopoietic Donor Cells With Shorter Telomere Length

Telomere length measurement is recommended in donors of patients with severe aplastic anemia (SAA) to screen for silent inherited telomeropathy. This was based on prior reports of delayed engraftment and graft failure after hematopoietic stem cell transplantation (HSCT) when donors had short telomeres or were silent carriers of dyskeratosis congenita (DC)-causative mutations (Fogarty et al. Lancet 2003 and Awaya et al. Biol Blood Marrow Transplant. 2002). The challenging question is, in the absence of a known causative mutation, how short the donor's telomere length could be to be labeled as not suitable. Here, we summarize our patients with SAA who have been transplanted with HLA-matched related hematopoietic donor cells that were of variable telomere length. A total of eight patients were transplanted using the following conditioning in 6 patients (cases 2, 4, 5, 6 in table, and two with undetermined telomere length) that included fludarabine (35mg/m2) on day -6 to -2, cyclophosphamide (40mg/kg) on day -6 and -5, and rabbit antithymocyte globulin (thymoglobulin) (2.5mg/kg) on day -5 to -2. GVHD prophylaxis was mycophenolate mofetil and cyclosporine (CSA). Two patients (cases 1 and 3) had cyclophosphamide (50mg/kg) on day -5 to -2 and thymoglobulin (2.5mg/kg) on day -4 to -2 with CSA and methotrexate or steroids as GVHD prophylaxis.All eight patients (5 females and 3 males) with an average age of 7 (range 0.8-13.3 years) had bone marrow failure as a predominate feature and except for one patient (case 4) who had short stature, mental retardation and a brain MRI with bilateral encephalomalacia there were no abnormal physical findings, specifically no classical features of DC i.e. nail dystrophy, leukoplakia, and skin pigmentation. All donors had normal physical examination and normal CBC. History of consanguinity was reported in all patients except one. Patients had normal chromosomal fragility test, but the telomere length values for six of the patients and their donors were in the lower reference range of healthy Caucasian individuals (Table). Three patients had very short telomeres in practically all lymphocytes subsets (cases 3, 4, and 6) similar to the pattern observed in patients with DC. The telomere length results of the six donors were variable (table). One donor had very short telomeres (case 3) in all lymphocyte subsets. The telomere length result was not available for this donor prior to commencing conditioning, however, CD34 cell dose infused was adequate (9.29 X106/kg recipient weight). Genetic tests are ongoing to identify causative mutations. One patient with undetermined telomere length had a heterozygous mutation in the TINF2 gene that was not present in his donor.All eight patients engrafted successfully, median time to neutrophil engraftment was 22 (range, 11-29 days) and platelet engraftment 30 (range, 15-62 days). Median infused nucleated cell dose was 2.8 (range, 1.6-6.5 X108/kg) and CD34 cell dose was 5.8 (range, 1.1-11.2 X106/kg). Median donor chimerism was 100% for myeloid cells and 62% for T cells around 100 days post HSCT. None of our patients had acute GVHD and one patient had mild classic chronic GVHD of the skin. All patients are alive with median follow-up duration of 377 days (range, 152-907 days).In conclusion, fludarabine-based conditioning using reduced dose cyclophosphamide (80mg/kg) seems safe and feasible in our SAA patients with shorter telomeres. Hematopoietic stem cells obtained from related donors with shorter telomeres successfully rescued patients with SAA without signs of graft failure over a median follow-up of 377 days. It is not clear yet, whether these patients and donors have an inherited telomeropathy or whether the reference range of telomere lengths established from Caucasians is also applicable for Arabs or other ethnic groups as this could possibly exclude donors unnecessarily. These studies are ongoing and an update will be presented. Disclosures:No relevant conflicts of interest to declare.

Pre-transplant prognostic factors of long-term survival after allogeneic peripheral blood stem cell transplantation with matched related/unrelated donors

Mobilized peripheral blood has become the predominant stem cell source for allogeneic hematopoietic cell transplantation. In this retrospective single center study of 442 patients with hematologic malignancies, we analyzed prognostic factors for long-term survival after peripheral blood stem cell transplantation from HLA-matched related or unrelated donors. To account for disease/status heterogeneity, patients were risk-stratified according to the Disease Risk Index. Five-year overall survival was similar after transplants with matched related and unrelated donors (45% and 46%, respectively; P=0.49). Because donor age ≥60 years impacted outcome during model building, we further considered 3 groups of donors: matched unrelated (aged <60 years by definition), matched related aged <60 years and matched related aged ≥60 years. In multivariate analysis, the donor type/age group and the graft CD34(+) and CD3(+) cell doses impacted long-term survival. Compared with matched unrelated donor transplant, transplant from matched related donor <60 years resulted in similar long-term survival (P=0.67) while transplant from matched related donor ≥60 years was associated with higher risks for late mortality (hazard ratio (HR) 4.41; P=0.006) and treatment failure (HR: 6.33; P=0.009). Lower mortality risks were observed after transplant with CD34(+) cell dose more than 4.5×10(6)/kg (HR: 0.56; P=0.002) and CD3(+) cell dose more than 3×10(8)/kg (HR: 0.61; P=0.01). The Disease Risk Index failed to predict survival. We built an "adapted Disease Risk Index" by modifying risks for myeloproliferative neoplasms and multiple myeloma that improved stratification ability for progression-free survival (P=0.04) but not for overall survival (P=0.82).

Analysis Of 402 Cord Blood Units To Assess Factors Influencing Infused Viable CD34+ Cell Dose: The Critical Determinant Of Engraftment

IntroductionThe selection of CB units with a high engraftment potential is key to the success of single and double-unit CB transplantation (CBT). However, the best predictors of engraftment potential at the time of unit selection and prior to infusion are not established. MethodsWe analyzed determinants of engraftment in recipients of double-unit CBT at our transplant center (TC) who underwent myeloablative conditioning for hematological malignancies from 10/2005-5/2013. As infused viable CD34+ cell dose was critical to engraftment in this analysis, we then evaluated units thawed at our center for the two determinants of infused viable CD34+ cell dose: post-thaw CD34+ cell recovery and CD34+ cell viability. CD34+ cell recovery was calculated as TC CD34+ cell count/Bank CD34+ cell count. Post-thaw viability was evaluated by flow cytometry using modified ISHAGE gating and 7-AAD exclusion to assess the percentage of viable CD34+ cells (of total present). ResultsThe cumulative incidence of neutrophil engraftment in the 128 myeloablative double-unit CBT recipients was 96% (95%CI: 93-100%). Reported Bank total nucleated cell (TNC) dose, Bank CD34+ cell dose, TC infused TNC dose, TC infused total CD34+ cell dose, TC infused viable CD34+ cell dose, and TC CFU dose were all significantly associated with neutrophil engraftment on univariate analysis. However, only the infused viable CD34+ cell dose was significant on multivariate analysis [HR=1.95 (1.33-2.86), p = 0.001, Figure]. Platelet engraftment was also strongly associated with infused viable CD34 cell dose (data not shown). To evaluate the reliability of CD34+ cell counts and determinants of viability, 402 units (302 domestic and 100 international) from 43 Banks thawed at our TC between 10/2005-5/2013 were then analyzed. For 7 selected Banks accounting for 135 (33%) units, there was strong correlation between Bank and TC CD34+ cell counts (r2 = 0.8, p < 0.001) with a median 92% CD34+ cell recovery at the TC (range 44-189%). However, for the remainder, there was greater variation in CD34+ cell recovery (range 12-1480%, median 107%) with a weaker (but still significant) correlation between CD34+ cell counts (r2 = 0.5, p < 0.001). In 40 (10%) units the recovery was less than 66%. Finally, while the median post-thaw CD34+ cell viability was 92%, it ranged 34-99%, and 33 units (8%) had <75% viable CD34+ cells. Unit characteristics significantly associated with CD34+ cell viability are shown in the Table. Bank location (domestic vs. international), shipping distance (New York vs. Australia), processing method (manual vs. automated or semi-automated) and unit hematocrit did not correlate with viability. In multivariate analysis, Bank FACT accreditation, year of cryopreservation, and cryovolume were associated with viability. ConclusionInfused viable CD34+ cell dose was the critical determinant of neutrophil and platelet engraftment. Although correlation between Bank and TC CD34+ cell counts was excellent for some banks and post-thaw CD34+ cell viability was satisfactory for the majority of units, 17% of units had <66% CD34+ cell recovery and/or <75% CD34+ cell viability post-thaw. The variability in CD34+ cell recovery and viability was not random but linked to known differences in banking practice and at least one independent measure of Bank quality (FACT accreditation). These findings have significant implications to CB banking and transplantation. Although units can be selected based on CD34+ cell dose, TC must be able to react to lower than expected post-thaw CD34+ cell counts and/or low CD34+ cell viability. Thus, methods to measure the infused viable CD34+ cell dose on transplant day (or other rapidly available measures of potency) should be employed to ensure the delivery of a graft with optimal engraftment potential and a back-up strategy in case of a compromised unit. This is even more important in single-unit CBT in which, unlike double-unit CBT, engraftment is solely dependent on a single unit.▪ [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Long-Term Survival After Donor Lymphocyte Infusion For Hematological Malignancies After Allogeneic Hematopoietic Cell Transplantation

Relapse is the major cause of death after allogeneic hematopoietic cell transplantation (HCT) for hematological malignancies and can be treated with donor lymphocyte infusions (DLI). Initial low dose DLI followed by escalating DLI doses have been used to minimize the risk of graft-versus-host disease (GVHD) in patients with relapsed chronic myeloid leukemia (CML). The impact of initial CD3+ cell dose on outcome after DLI in patients treated for other hematological malignancies is limited. We retrospectively analyzed data of 75 patients who were treated with DLI after HCT at our institution over the last 20 years. The primary objective of this analysis was to determine the effect of the initial CD3+ cell dose in DLI on overall survival (OS).The median age of the cohort was 43 (range, 18 - 71) years, 60% were male. Patients received transplants from related (n=53) or unrelated (n=22) donors for treatment of CML (n=18), acute myeloid leukemia (n=29), myelodysplastic syndrome (n=3), acute lymphoblastic leukemia (n=9), multiple myeloma (n=8), lymphoma (n=7) and paroxysmal nocturnal hemoglobinuria (n=1). Thirty-three patients (44%) received reduced-intensity conditioning regimens. DLI were given for mixed chimerism (n=5), relapse/progression (n=58) or prophylactically in patients with high risk disease (n=12). The median time intervals from HCT to relapse/progression and HCT to DLI for mixed chimerism were 15 (range, 1-80) and 20 (range, 1-169) months, retrospectively. Prophylactic DLI were given between 1 and 25 months after HCT. Therapy prior to DLI consisted of cytoreductive chemo-/radiotherapy with or without tyrosine kinase inhibitors (TKI) in 33 (44%) patients, TKIs alone in 10 (13%) and immunomodulatory drugs in 3 (4%) patients. Twenty-nine (39%) patients received DLI alone. Initial DLI CD3+ cell dose/kg was <1x107 (n=28; Group A), >1.0 to <10x107 (n=28; Group B), and >10x107(n=16; Group C), in 3 patients the cell dose was not available. Of note, 24 patients received escalating doses of CD3+ cells.Response evaluation three months after DLI for evaluable patients with relapse/progression or mixed chimerism (n=60) revealed complete response (CR) in 30 (47%) and no response in 28 (44%) patients. Two patients developed aplasia and were rescued with second HCT. After prophylactic DLI 6/12 (50%) patients remained in CR whereas 6 (50%) experienced relapse between 3 and 21 months after DLI. Twenty-nine (39%) patients are currently alive including eight with malignant disease after a median follow-up of 69 months (range, 1-193). Seventeen (24%) patients developed acute or chronic GVHD after DLI. The risk for GVHD was significantly higher in patients receiving higher (Group B and C) compared to lower doses (Group A; p=0.04) of CD3+. Eight patients died due to severe GVHD. Higher CD3 cell doses did not result in lower relapse rates or better response (p=0.23). OS rates at 5 years were 50%, 45%, and 6% for Groups A, B, and C, respectively. Compared to lower doses initial DLI CD3+ cell dose of >10x107/kg was significantly associated with a reduced overall survival after DLI (p=0.003, Figure 1). Of note, conditioning regimen applied, donor type and reason for DLI administration had no significant influence on overall survival.Our results show that an initial DLI CD3+ cell dose of >10x107/kg is associated with reduced survival rates. These findings are clinically relevant, and support a recommendation to infuse <10x107 CD3+ cells/kg for treatment of hematological malignancies after HCT. Additionally, molecular monitoring of patients is warranted to allow the use of DLI early in the course of their disease. [Display omitted] Disclosures:No relevant conflicts of interest to declare.