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We evaluate the safety of bendamustine as a bridge to stem cell transplantation (SCT) in patients with relapsed/refractory lymphoma and residual disease after salvage therapy. Thirty-four subjects without complete responses (CR) received bendamustine 200 mg/m

Alternative donor transplantation with the haplo-cord platform allows the use of a lower-dose single umbilical cord blood unit (CBU) by co-infusion of third-party CD34+-selected cells from a haploidentical relative, which provides early transient engraftment while awaiting durable CBU engraftment. In our experience, ~15% of patients lack a suitable haploidentical donor. Here we report 26 patients who underwent haplo-cord transplant using CD34+-selected partially matched unrelated donor grafts. Twenty-four were conditioned with fludarabine/melphalan +/− low-dose TBI (n = 16). Twenty-five received ATG and all received posttransplant tacrolimus and mycophenolate mofetil. Median time to neutrophil and platelet recovery was 11 and 18 days. CBU engraftment, with CD33 and CD3 >5% cord chimerism in the myeloid/lymphoid compartment by day +60, occurred in 20 of 24 patients (83%). Incidence of grade 2–4 acute graft-versus-host disease (GVHD) was 27% at day +100, and chronic GVHD was 4% at 1 year. Overall survival at 1 year was 54%. For patients in need of an alternative transplant who lack a haploidentical donor, haplo-cord transplantation using CD34+-selected partially matched unrelated donor grafts results in rapid engraftment with no increased rate of cord graft failure or GVHD.

Haplo-identical transplant with posttransplant cyclophosphamide (haplo) and umbilical cord blood transplant supported by third-party CD34 cells (haplo-cord) are competing approaches to alternative donor transplant. We compared, in adults younger than age 60 years, the outcomes of 170 haplo at 1 institution with that of 137 haplo-cord at 2 other institutions. All received reduced intensity conditioning with fludarabine and melphalan ± total body irradiation. GVHD prophylaxis for haplo consisted of cyclophosphamide, tacrolimus, and mycophenolate, whereas haplo-cord received antithymocyte globulin, tacrolimus, and mycophenolate. Haplo transplant used mostly bone marrow, and peripheral blood stem cells were used in haplo-cord transplants. Haplo-cord were older and had more advanced disease. Haplo-cord hastened median time to neutrophil (11 vs 18 days, P = .001) and platelet recovery (22 vs 25 days, P = .03). At 4 years, overall survival (OS) was 50% for haplo-cord vs 49% for haplo. Progression-free survival (PFS) was 40% for haplo-cord vs 45% for haplo. In multivariate analysis, the disease risk index was significant for OS (hazard ratio, 1.8; 95% confidence interval, 1.48-2.17; P = .00) and PFS. Total body irradiation was associated with decreased recurrence and improved PFS, age >40 with increased nonrelapse mortality. The type of transplant had no effect on OS, PFS, relapse, or nonrelapse mortality. Cumulative incidence of grade 2-4 acute graft-versus-host disease (GVHD) by day 100 was 16% after haplo-cord vs 33% after haplo (P < .0001), but grade 3-4 GVHD was similar. Chronic GVHD at 1 year was 4% after haplo-cord vs 16% after haplo (P < .0001). Haplo or haplo-cord results in similar and encouraging outcomes. Haplo-cord is associated with more rapid neutrophil and platelet recovery and lower acute and chronic GVHD. Institutional review board authorization for this retrospective study was obtained at each institution. Some patients participated in trials registered at www.clinicaltrials.gov as #NCT01810588 and NCT 01050946.

High-dose melphalan (MEL200) followed by autologous stem cell transplantation (ASCT) remains a standard of care for multiple myeloma (MM). Bendamustine induces responses in MM resistant to other alkylators. Our prior Phase I trial adding bendamustine to MEL200 transplant conditioning resulted in no additional toxicity. We now report a single-arm, phase II study that evaluated the efficacy of bendamustine 225 mg/m2 with MEL200 conditioning for ASCT in 18 patients with newly diagnosed MM (NDMM) and 17 with relapsed or refractory MM (RRMM). The primary end point was the complete response (CR/sCR) rate at day+ 100. Sample size was determined according to Simon's two-stage design. At stage 1, sixteen patients entered the study. As there were eight patients with CR/sCR, enrollment increased to 28 patients. Sixteen out of the first 28 evaluable patients achieved CR/sCR, meeting the design criteria. Enrollment was then expanded to a total of 35 patients. 51% achieved a CR/sCR. After a median follow-up of 65 months, 21 patients progressed, including 7 deaths. The median PFS for NDMM and RRMM was 48 and 45 months, respectively. Bendamustine/MEL200 conditioning resulted in excellent overall and depth of response as well as PFS, particularly in the RRMM patients, and is worthy of further investigation (NCT00916058).

Epstein-Barr virus (EBV) reactivation and post-transplant lymphoproliferative disorders (PTLD) are common and potentially fatal complications after allogeneic transplantation with mismatched donors and T-cell depletion. Haplo-cord transplantation combines a mismatched UCB graft with third-party cells. Conditioning involves thymoglobulin. EBV reactivation and PTLD were common in initial patients. As of March 2017, we administered a prophylactic dose of rituximab 375 mg/m

6093 Background: ICAM-1 is a cell surface glycoprotein that is typically expressed on endothelial cells and immune cells and a ligand for LFA-1 integrin. It is also overexpressed in several malignancies, in particular anaplastic and advanced thyroid cancer. We designed an affinity tuned ICAM-1-directed CAR T cell (micromolar affinity) that preferentially binds overexpressed ICAM-1 on tumor cells and spares normal cells. The CAR T cells also express somatostatin receptor 2 (SSTR2), which allows tracking of CAR T cells in vivo via DOTATATE PET/CT scan. Murine studies showed excellent responses in ICAM-1 expressing thyroid cancer without significant toxicities. We are conducting a first-in-human phase 1 clinical trial to evaluate the feasibility, safety and preliminary efficacy of ICAM-1 in patients with relapsed/refractory thyroid cancer or anaplastic thyroid cancer who are BRAF wild-type, or BRAF mutated after failure of BRAF specific therapy (NCT04420754). Methods: This is a dose-escalation study with modified toxicity probability interval design and cohorts of 3 Patients. Patients receive a single dose of 1x 107 (Cohort 1), 1 x 108 (Cohort 2) or 5 x 108 (Cohort 3) ICAM-1 CAR T cells after FLU/CY lymphodepleting (LD) chemotherapy. Additional CAR T infusion is allowed if patients achieve partial response or stable disease. Whole-body Fluorodeoxyglucose (FDG) and DOTATATE PET/CT is used to stage tumor and track CAR T cells in vivo, respectively. Results: All ICAM-1 CAR T infusion products met target transduction efficiency. Two patients with progressive anaplastic thyroid cancer received ICAM-1 CAR T therapy at dose-level I. Evaluation of CAR T cellular kinetics demonstrated transient peripheral blood CAR T cell expansion. One patient developed grade 1 cytokine release syndrome (CRS) with fever. Several tumor lesions from this patient showed DOTATATE avidity, indicating CAR T homing to the tumor, concomitant with decrease in FDG avidity, suggesting biological activity at ̃2 weeks post CAR T infusion. DOTATATE avidity at 2 weeks post CAR T infusion also appeared to match that of CAR T abundance in the blood. Updated results on additional patients and cohorts will be presented. Conclusions: Adoptive cellular therapy with ICAM-1 directed CAR T is safe and feasible at dose level 1 in patients with anaplastic thyroid cancer. DOTATATE PET allows visualization of expansion and homing of SSTR2 expressing CAR T cells, while concomitant FDG PET permits correlation with biological activity. Clinical trial information: NCT04420754.

We conducted a prospective evaluation of cord blood (CB)–derived adoptive cell therapy, after salvage chemotherapy, for patients with advanced myeloid malignancies and poor prognosis. Previously, we reported safety, feasibility, and preliminary efficacy of this approach. We present updated results in 31 patients who received intensive chemotherapy followed by CB infusion and identify predictors of response. To enhance the antileukemic effect, we selected CB units (CBU) with shared inherited paternal antigens and/or noninherited maternal antigens with the recipients. Twenty-eight patients with acute myeloid leukemia (AML), 2 with myelodysplastic syndrome, and 1 in chronic myeloid leukemia myeloid blast crisis were enrolled; 9 had relapsed after allogeneic transplant. Response was defined as

Alternative donor transplantation with the haplo-cord platform allows the use of a lower-dose single umbilical cord blood unit (CBU) by co-infusion of third-party CD34

Introduction: Acute myeloid leukemia (AML) is heterogenous disease with a range of cytogenetic and molecular changes. Several molecular mutations identified in AML patients at diagnosis have prognostic implications and play important roles in guiding induction and consolidative treatment decisions. The prognostic impact of mutations peri allogeneic stem cell transplant are less well characterized. In this study, we examine the significance of pre and by D100 Post-transplant mutation status in AML patients underwent Fludarabine/Melphalan conditioned reduced intensity allogeneic stem cell transplant (SCT). Methods: AML patients who are in morphologic complete remission (CR1 or greater) with available molecular mutation at diagnosis, within 6 weeks prior to allogeneic SCT, and by 100 days post-transplant were included. Variables analyzed included baseline demographics, clinical variables (CIBMTR disease risk index (DRI), type of transplant, ELN risk, performance status) and 23 recurring molecular mutations. Analysis was also performed by grouping mutations into six pre-defined gene groups based on gene function (Table 2). Multivariable cox regression analysis was adjusted for age, gender, DRI and molecular mutation. Backward selection method was used to select the best combination of genes that is associated with overall survival (OS) and relapse-free survival (RFS). Results : A total of 142 AML patients with molecular genetic data available from 2014 to June, 2020 at Weill Cornell Medicine/New York Presbyterian Hospital were analyzed. Clinical characteristics of the patients are summarized in Table 1. The median age was 58 years (range 20 -78). Total of 261 mutations were detectable at diagnosis (Table 3). Prior to allo SCT and by D100, the detectable mutations were 87 and 40 respectively, which represent 56 and 26 patients. High-dose chemotherapy was less effective on clearing DNMT3A, ASXL1, TET2 (DAT) or IDH mutations, resulting in over-representation of DAT and IDH mutations prior to transplant. With a median follow-up time of 25 months, the median overall survival for the group was 40.8 months. The presence of mutations in TP53 at diagnosis was associated with worse OS by both univariate (HR 3.67, p=0.0030, CI 1.56-8.68) and multivariate analysis (HR 4.75, p=0.0014, CI 1.82-12.39) with median OS reduced from 49.3 to 19.3 months (p=0.002). High CIBMTR DRI (HR 0.17, p=0.0018, CI 0.05-0.51) predicted reduced OS and RFS, and Age >60 at diagnosis was associated with worse OS (HR 1.7 CI 1.04-3, p 0.03). Presence of any molecular mutation prior to transplant did not impact OS or RFS. For patients with any persistent mutations by D100 post-transplant, both OS ( HR 2.04, p 0.027, CI 1.08-3.8) and RFS (HR 1.99, p 0.025, CI 1.09-3.6,) were reduced in the univariate analysis, but not on multivariate analysis (HR 1.88, p 0.5, CI 0.99-3.49). Analysis based on six mutational groups (table 2) did not show any difference in their OS or RFS. However, worse RFS was independently associated with persistent IDH1 (HR 3.8, p 0.004, CI 1.07-56,), TET2 (HR 3.9, P 0.04, CI 1.04-14.1), and FLT3-ITD (HR 4.5, p 0.01, CI 1.7-52). Worse OS was independently associated with persistent TET2 (HR 3.9, p 0.013, CI 1.04-14.1), with a trend towards worse OS for IDH1, FLT3-ITD, with a trend towards worsening OS and RFS for ASXL1 (OS HR 7.4, p 0.06, CI 0.86 -63; RFS HR 4.9, p 0.06, CI 0.9-26) and DNMT3A (OS HR 2.3, p 0.12, CI 0.86-6.9; RFS 2.9, p 0.08, CI 0.98-8). Association with worse clinical outcomes remained significant after multivariate analysis for TET2 (both OS HR 3.98 p 0.041, CI1.07- 32 and RFS HR 5.8, p 0.032, CI 1.1- 29), IDH1 (RFS HR 8.02, p 0.049, CI 1.02 - 65) and FLT3-ITD (RFS HR 11.4, p0.010, CI 2.2- 80). Conclusions: Presence of TP53 mutations was associated with worse OS. Presence of pre-transplant mutation did not impact RFS or OS. Persistent presence of mutations in TET2, IDH1 and FLT3-ITD after Fludarabine/melphalan conditioning regimen allogeneic SCT were associated with shorter RFS and OS (in the case of TET2) independent of CIBMTR DRI. This analysis supports association of adverse outcomes in AML patients with selected persistent mutations by D100 post-transplant in reduced intensity transplant setting. Post-transplant strategies that can further eliminate persistent mutations should be investigated in prospective studies. Figure 1 Figure 1. Disclosures Lee: Pin Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Innate: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees. Desai: Kura Oncology: Consultancy; Bristol Myers Squibb: Consultancy; Agios: Consultancy; Takeda: Consultancy; Janssen R&D: Research Funding; Astex: Research Funding. Ritchie: Protaganist: Consultancy, Honoraria; Incyte: Consultancy, Honoraria, Speakers Bureau; Celgene/BMS: Consultancy, Other: travel support, Speakers Bureau; Bristol Myers Squibb: Consultancy, Research Funding; ARIAD Pharmaceuticals: Ended employment in the past 24 months, Speakers Bureau; Novartis: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Takeda: Consultancy, Honoraria; Astellas: Consultancy, Research Funding; NS Pharma: Research Funding; Abbvie: Consultancy, Honoraria; Jazz: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding. Roboz: MEI Pharma - IDMC Chair: Consultancy; Daiichi Sankyo: Consultancy; Helsinn: Consultancy; Jazz: Consultancy; Bristol Myers Squibb: Consultancy; Glaxo SmithKline: Consultancy; Novartis: Consultancy; Janssen: Consultancy; Otsuka: Consultancy; Celgene: Consultancy; Mesoblast: Consultancy; Blueprint Medicines: Consultancy; Jasper Therapeutics: Consultancy; AbbVie: Consultancy; Actinium: Consultancy; Agios: Consultancy; Amgen: Consultancy; Astex: Consultancy; Astellas: Consultancy; AstraZeneca: Consultancy; Bayer: Consultancy; Janssen: Research Funding; Pfizer: Consultancy; Roche/Genentech: Consultancy.

Background Direct thaw and administration of previously cryopreserved peripheral blood stem cell products is a commonly used practice and should be performed rapidly to reduce cellular damage caused by dimethyl sulfoxide exposure. Cells are typically thawed at the bedside and infused by gravity through a high-flow-rate central venous catheter. An existing nontunneled catheter is occasionally used instead and often results in a slower infusion rate. To ensure expedient and consistent infusions, we validated and implemented the use of an infusion pump for thawed peripheral blood stem cells. Study design and methods Validation was performed in two phases: in vitro simulation and in vivo clinical assessment. Total nucleated cell recovery and viability plus progenitor cell viability and potency were compared in vitro between two cryopreserved peripheral blood stem cell units that were either passed through a preset infusion pump or drained by gravity. The infusion rate, adverse events, and engraftment times were retrospectively compared between patients who received infusions by infusion pump (n = 35) and by gravity (n = 38). Results No significant differences were observed in vitro between the infusion methods for all measured variables. Overall infusion rates were similar in vivo for both groups but were significantly lower for patients who had nontunneled catheters that delivered the infusion by gravity. The time to neutrophil and platelet engraftment was similar for both groups. Conclusion This is the first study to assess the use of an infusion pump for stem cell transplant. The use of an infusion pump for peripheral blood stem cell infusion is safe, provides a reliable and consistent infusion method, and can mitigate the effect of the type of venous access line used.

Background: Daratumumab (DARA) is a monoclonal antibody which targets CD38 on plasma cells and B cell progenitors. DARA has been effectively combined with other therapies in newly diagnosed and relapsed/refractory multiple myeloma (RRMM), while DARA-based induction regimens in transplant-eligible patients (pts) are increasingly being used in clinical practice. Given that hematopoietic stem cells also express CD38, DARA may potentially affect stem cell mobilization and hematopoietic reconstitution following autologous stem cell transplant (ASCT). Although no clinically significant impact of DARA on stem cell mobilization or hematopoietic recovery was described in large phase 3 trials of triplet induction regimens +/- DARA in newly diagnosed MM, stem cell yields were lower and plerixafor more commonly used in the DARA-containing arms [Moreau et al, Lancet 2019; Voorhees et al, Blood 2020]. Significantly longer time to neutrophil (PMN) engraftment was also reported in pts receiving DARA-based induction who underwent upfront ASCT [Al Saleh et al, Am J Hematol 2020]. In this study, we examine the impact of timing of DARA administration pre-mobilization on day 4 pre-harvest peripheral blood CD34 cell count, stem cell apheresis yield, and post-ASCT engraftment. Methods: Between 1/1/2016 and 12/31/2019, newly diagnosed and RRMM pts receiving DARA-based induction regimens with ≥1 dose of DARA administered within 1 month prior to stem cell mobilization were identified retrospectively and compared to matched controls receiving similar induction regimens without DARA. Granulocyte colony-stimulating factor (G-CSF) was administered per institutional standards and plerixafor added based on day 4 pre-harvest peripheral blood CD34 counts. PMN and platelet engraftment post-ASCT was defined as the first of 3 consecutive days with sustained PMN count >500 x 106/L and independence from platelet transfusion in the preceding 7 days with a count >20 x 109/L, respectively. Pre-harvest peripheral blood CD34 counts and stem cell apheresis yields were obtained from the Cellular Therapy Laboratory at NewYork-Presbyterian Hospital. The study was approved by the Weill Cornell Medicine IRB. Results: We identified 16 pts who received DARA-based induction with ≥1 dose of DARA administered within 1 month of apheresis (DARA group) and 16 non-DARA-containing regimen-matched controls (non-DARA group). Demographics of the DARA and non-DARA groups were well matched (Table 1). DARA pts received their last dose of DARA a mean of 17.3 days prior to the first day of apheresis, with 8 pts receiving their last dose within 2 weeks and the remaining 8 pts between 2 weeks and 1 month prior. Overall, mobilization outcomes were inferior in the DARA group (Table 2). DARA pts had significantly lower day 4 pre-harvest peripheral blood CD34 counts compared to non-DARA pts (17.2 vs 35.4 cells/µL; P=0.0146). Institutional algorithm required plerixafor to be given for day 4 CD34 count ≤40 cells/µL. Fifteen of the 16 DARA pts received plerixafor vs. 11 non-DARA pts (P=0.07). Additionally, DARA pts required significantly more apheresis days (2.4 vs 1.6 days; P=0.0279). Differences in stem cell yield were not significant (8 vs 10 x106cells/kg; P=0.1391). Hematopoietic recovery post-ASCT was not affected by DARA administered in the month preceding mobilization. Conclusions: In summary, we report lower day 4 pre-harvest peripheral blood CD34 count, increased requirement for plerixafor, and longer apheresis duration in newly diagnosed and RRMM pts receiving DARA within 1 month ofstem cell mobilization. These limitations are largely overcome by plerixafor usage which, combined with G-CSF, resulted in successful stem cell collection in all patients. Limitations in our study include small sample sizes, retrospective control selection, and fewer pts in the DARA group achieving ≥VGPR prior to mobilization. Nevertheless, our findings are consistent with inferior mobilization outcomes reported in the DARA-containing arms of phase 3 trials of triplet induction +/- DARA and highlight the nearly universal requirement for plerixafor usage when DARA is administered within a month prior to apheresis. Prospective study of day 4 pre-harvest peripheral blood CD34 counts and other predictors of stem cell yield should be incorporated into future clinical trials of CD38 monoclonal antibody-based induction regimens for transplant-eligible MM pts. Disclosures Rossi: Janssen: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees. Niesvizky:GSK: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Rosenbaum:Amgen: Research Funding; GlaxoSmithKline: Research Funding; Akcea: Honoraria; Celgene: Honoraria; Janssen: Research Funding.

High-dose melphalan (MEL200) followed by autologous stem cell transplantation (ASCT) remains a standard of care for multiple myeloma (MM). Bendamustine induces responses in MM resistant to other alkylators. Our prior Phase I trial adding bendamustine to MEL200 transplant conditioning resulted in no additional toxicity. We now report a single-arm, phase II study that evaluated the efficacy of bendamustine 225 mg/m

Introduction Haplo-cord transplantation – the co-infusion of a single cord unit with CD34-selected cells from a haplo-identical donor, provides an alternate stem cell source for patients lacking HLA-matched donors. Anti-thymocyte globulin (ATG) is routinely used in haplo-cord preparative regimens to reduce graft failure, graft vs. host disease (GVHD) and graft vs. graft reactions. However, excessive depletion of cord lymphocytes may compromise immune reconstitution and graft vs. tumor (GVT) effects. Methods We reviewed lymphocyte recovery and outcome data for consecutive patients with hematologic malignancy who underwent haplo-cord transplantation at Weill Cornell Medicine between June 2012 and June 2019. All were conditioned using fludarabine and melphalan with or without total body irradiation (200-600cGy). All received rabbit ATG (Thymoglobulin), initially at a total dose of 6mg/kg (2012-2013) and later at a total dose of 4.5mg/kg (2013 onward). Data was collected as part of study 01810588 registered at clinicaltrials.gov. Probabilities of relapse and non-relapse mortality (NRM) were generated using cumulative incidence estimates to accommodate competing risks. Probabilities of overall survival (OS) and progression-free survival (PFS) were calculated using Kaplan-Meier estimates. Results Our study included 220 haplo-cord transplant recipients with a median age of 58 yrs (Range: 18 – 76 yrs). The majority had myeloid disease (AML – 54%, MDS/MPN – 19.5%, CML – 2%). Conditioning incorporated TBI for 120 patients (55%). ATG was dosed at 6mg/kg for 41 patients (19%). The median absolute lymphocyte count (ALC) at first ATG exposure was 0.4 × 10^9/L (IQR25-75: 0.2-0.7 × 10^9/L). The median patient weight was 75.5kg (IQR25-75: 65.4-89.9kg). Neutrophil and platelet engraftment occurred at a median of 12 days (IQR25-75: 10-16 days) and 22 days (IQR25-75: 17-35 days) respectively. Graft failure was observed in 16 patients (7%). Rapid early recovery of CD19+ lymphocytes, CD56+ natural killer cells and IgG levels was observed. T-cell recovery was delayed, with a gradual increase observed from Day 100 (Figure). Overall PFS and OS at 2 yrs were 30% (CI 24-37%) and 39% (CI 32-46%) respectively. The 2 yr cumulative incidence of NRM was 33% (+/- 3% SEM). The overall 2 yr incidence of relapse was 37% (+/- 3% SEM), however there was a significant difference in relapse incidence between patients treated with 6mg/kg ATG (54%) versus 4.5mg/kg (31.5%) (p=0.009). Conclusion Haplo-cord transplant facilitates early neutrophil engraftment with early normalization of B- and NK-lymphocytes. An observed delay in T-cell recovery may be due to the use of ATG in this platform and higher ATG doses result in a greater incidence of relapse. Our data supports the minimization or replacement of ATG in haplo-cord transplant. An analysis of GVHD incidence and viral reactivation events is ongoing and will be presented.

Direct thaw and administration of previously cryopreserved peripheral blood stem cell products is a commonly used practice and should be performed rapidly to reduce cellular damage caused by dimethyl sulfoxide exposure. Cells are typically thawed at the bedside and infused by gravity through a high-flow-rate central venous catheter. An existing nontunneled catheter is occasionally used instead and often results in a slower infusion rate. To ensure expedient and consistent infusions, we validated and implemented the use of an infusion pump for thawed peripheral blood stem cells.Validation was performed in two phases: in vitro simulation and in vivo clinical assessment. Total nucleated cell recovery and viability plus progenitor cell viability and potency were compared in vitro between two cryopreserved peripheral blood stem cell units that were either passed through a preset infusion pump or drained by gravity. The infusion rate, adverse events, and engraftment times were retrospectively compared between patients who received infusions by infusion pump (n = 35) and by gravity (n = 38).No significant differences were observed in vitro between the infusion methods for all measured variables. Overall infusion rates were similar in vivo for both groups but were significantly lower for patients who had nontunneled catheters that delivered the infusion by gravity. The time to neutrophil and platelet engraftment was similar for both groups.This is the first study to assess the use of an infusion pump for stem cell transplant. The use of an infusion pump for peripheral blood stem cell infusion is safe, provides a reliable and consistent infusion method, and can mitigate the effect of the type of venous access line used.

Background: Multiple myeloma (MM) remains incurable with eventual relapse and death occurring despite multiple lines of chemotherapy. Standard frontline therapy for MM has traditionally consisted of combinations of immunomodulatory drugs (IMiDs), proteasome inhibitors (PIs), and dexamethasone followed by consolidation with high-dose melphalan and autologous stem cell transplantation (ASCT). A randomized trial using IMiD and PI-based induction demonstrated significant progression-free survival (PFS) benefit with upfront ASCT in consolidation compared to ASCT in second-line at relapse, but no OS benefit (Attal et al, NEJM, 2017). Delay of ASCT to second-line or beyond may in part be due to the aforementioned lack of OS benefit shown with upfront ASCT and increase of sustained deep responses, including MRD negativity, to novel frontline 3 and 4-drug regimens and continuation of therapy in the frontline. We performed a chart review comparing PFS1, PFS2, and overall survival (OS) of patients who underwent upfront ASCT as consolidation to those who received ASCT in the second-line after one relapse ('delayed ASCT'). The study was approved by the Institutional Review Board at Weill Cornell Medical College. Methods: 124 MM patients who underwent ASCT either as consolidation in first-line or delayed ASCT after relapsing on one prior treatment between 2010-2016 were included. Demographics and clinical parameters were extracted from the electronic medical record. PFS1, PFS2, and OS were calculated from date of diagnosis to first relapse, second relapse, and death, respectively. Patients were censored if lost to follow-up prior to experiencing the relevant event. PFS1, PFS2, and OS of patients receiving upfront ASCT were compared to those of patients receiving delayed ASCT. Log-rank tests were used to statistically evaluate differences between Kaplan-Meier PFS/OS curves. Cox proportional hazards models were used to calculate hazard ratios (HR) using upfront ASCT as the reference treatment. Results: Among the 124 patients, 93 underwent upfront ASCT as consolidation and 31 underwent delayed ASCT after relapsing on one prior line of therapy (Table 1). Induction regimens and pre-transplant therapies received are detailed in Table 1. Of the delayed group patients, 6 underwent ASCT directly without second-line induction and 25 as consolidation after second-line therapy. Patients receiving upfront ASCT had significantly longer median PFS1 compared to patients who received delayed ASCT (6.45 vs 1.25 years; P Conclusions: In this cohort of 124 MM patients undergoing ASCT as consolidation in the upfront setting or delayed ASCT in second-line after relapse, upfront ASCT was associated with significantly improved PFS1 and PFS2, similar to findings by Attal et al. However, in that study, no difference in OS was seen between upfront and delayed groups, while our data, with longer follow-up, showed median OS trending towards significance. This has important implications as with use of novel induction regimens and maintenance therapy, ASCT is more commonly being delayed to early relapse in second-line or beyond. If transplant is intended to be used in the first few lines of therapy, our data show that delaying ASCT even to second-line has a significant negative impact on PFS. In addition, a shorter OS with delayed transplant was suggested although did not reach statistical significance, possibly due to small numbers or more patients with high-risk MM in the delayed group. It is also important to note the lack of daratumumab-based regimens which may have improved PFS/OS in either or both arms. Thus, our findings should be prospectively validated in a larger trial of ASCT as consolidation in first-line vs second-line or beyond using novel, monoclonal antibody-based regimens. Disclosures Rosenbaum: Janssen: Research Funding; Honoraria Akcea: Other: Accordant Health. Coleman:Gilead, Bayer, Celgene: Consultancy, Research Funding, Speakers Bureau; Kite Pharmaceuticals: Equity Ownership; Merck: Research Funding; Pharmacyclics: Speakers Bureau. Van Besien:Miltenyi Biotec: Research Funding. Niesvizky:Takeda, Amgen, BMS, Janssen, Celgene: Consultancy, Research Funding.

Introduction: CAR T therapy has improved overall survival for patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL) who otherwise have poor outcomes with traditional chemoimmunotherapy. Cytokine release syndrome (CRS) and neurotoxicity are well known side effect from CAR T therapy. Cytopenia has been reported as well. However, to our knowledge, transfusion requirements during the first 30 days post-CAR T treatment have not been reported. Here we report the cytopenia characteristics and transfusion requirements in 15 patients who received commercial Axicabtagene ciloleucel (Yescarta) CAR-T cell therapy. Methods: We retrospectively reviewed all DLBCL patients who received Yescarta between July 2018 through May 2019 at Weill Cornell Medical Center. All patients received cyclophosphamide (500mg/m2) and fludarabine (30mg/m2) lymphodepleting regimen from days -5 to -3 before the CAR T cell infusion. Cytopenia, granulocyte-colony stimulating factor (G-CSF) use, packed red blood cell (RBC) and platelet transfusion requirements during 30 days after CAR T infusion were examined. Cytopenia was defined according to CTCAE criteria. Grade 3 cytopenia was white blood cell (WBC) Results: Median age was 68 years (range, 21-86yr) with 53% males (Table 1). Ten patients (67%) experienced cytokine release syndrome (CRS) with 8 patients receiving at least 1 dose of tocilizumab. Five patients (33%) experienced immune cell-associated neurologic syndrome (ICANS) and all received dexamethasone. Among patients with ICANS, one required ventilation support, one had a focal seizure and one had cerebellar ischemic stroke. Ten (70%) of the 14 evaluable patients had a D30 restaging PET/CT. Two patients had progressive disease and12 patients achieved partial response (PR). On admission, grade 3 or 4 leukopenia or neutropenia was observed in 0 patients, except 1 patient (WBC14.1, but ANC 0). There were 2 patients had grade 3 anemia, none of the patients had grade 4 anemia or grade 3/4 thrombocytopenia. Between D0 and D30, grade 3 or 4 leukopenia or neutropenia was observed in 12 patients (Figure 1). Grade 3 or 4 anemia was observed in 6 and 5 patients and grade 3 or 4 thrombocytopenia in 9 and 6 patients respectively. A total of 6 patients (43%) required G-CSF, 6 (43%) and 6 (43%) patients required red blood cell transfusion and/or platelet transfusion support. The median PRBC and platelet transfusion was 0 (range, 0-8) and 0 (range, 0-19). Three (20%) of the 15 patients accounted for the majority of the transfusion support. Conclusion: Cytopenia was common during the first 30 days after CAR-T cell therapy. Although nearly half of the patients required G-CSF and transfusion support, few patients had a significant burden. Disclosures Van Besien: Miltenyi Biotec: Research Funding.

Background: Autologous stem cell transplantation (ASCT) performed early in the disease course or at first relapse leads to improved progression-free and overall survival in transplant-eligible patients with multiple myeloma (MM). Filgrastim, a recombinant granulocyte colony-stimulating factor (G-CSF), when used after ASCT has been shown to accelerate time to neutrophil engraftment (TNE), and in some studies, it has been associated with reduced length of hospitalization, infectious complications, and antibiotic use. Strategies that reserve G-CSF administration to when neutrophil recovery is delayed, have attempted to show that there is no difference in infectious complications, length of hospitalization or TNE when compared to early administration of G-CSF on the day after stem cell infusion (DOT). However, the optimal timing for administering G-CSF has not yet been determined in patients with MM undergoing ASCT. Methods: This is a retrospective, single-center analysis of patients with MM undergoing ASCT from mobilized peripheral blood stem cells. Patients enrolled in a clinical trial of high-dose lenalidomide and melphalan as conditioning therapy which mandated the administration of filgrastim from day +1 after DOT (Lenalidomide Plus Melphalan as a Preparative Regimen for Autologous Stem Cell Transplantation in Relapsed Multiple Myeloma, NCT01054196) were assigned to the early strategy group (ES). Patients receiving filgrastim as per our institutional guideline (starting on day +12 if ANC < 1000 cells/uL, or at the physician's discretion) were included in the delayed strategy group (DS). Patients were excluded from the analysis if their conditioning regimen included a different agent other than melphalan or lenalidomide. DOT was defined as the day of stem cell infusion. Date of neutrophil engraftment was defined as the first of three consecutive days with an ANC ≥ 500 cells/uL. TNE was calculated as the time from DOT to the date neutrophil engraftment. Total duration of neutropenia was defined as the time from onset of neutropenia (ANC < 500 cells/uL) to date of neutrophil engraftment. Length of hospitalization was defined as the time from DOT to the day of discharge. Results: We identified 59 patients in the ES group and 39 patients in the DS group from 08-16-2010 to 05-22-2019, for a total of 98 included in this analysis. Median age was 60 and 65 years in the ES and DS groups, respectively. Patients received a comparable dose of CD34+ cells, 5.05x106/kg in the ES group vs 4.66x106/kg in the DS group (p = 0.48). The ES group started filgrastim administration earlier (day +1 vs +9, p < 0.001) and received a greater median number of doses (10 vs 4, p < 0.001) as compared to patients in the DS group. Median time to neutrophil engraftment was shorter in the ES group compared to the DS group (10 vs 12 days, p < 0.001), as was the total duration of neutropenia (5 vs 6 days, p < 0.001). Documented infections were just as likely in both groups, 37% in the ES group and 39% in the DS group (p = 1). Length of hospitalization was shorter in the ES group as compared to the DS group (15 vs 17 days, p = 0.01). Discussion: Filgrastim use guided by an ES decreased the time to neutrophil engraftment, the duration of neutropenia and the length of hospitalization compared to a DS. Further analyses to identify predictive factors associated with a reduction in infectious complications and length of stay are underway, with the aim of developing a risk-adapted strategy for the use of filgrastim in patients with MM undergoing ASCT. Disclosures Van Besien: Miltenyi Biotec: Research Funding. Coleman:Kite Pharmaceuticals: Equity Ownership; Merck: Research Funding; Pharmacyclics: Speakers Bureau; Gilead, Bayer, Celgene: Consultancy, Research Funding, Speakers Bureau. Rosenbaum:Janssen: Research Funding; Honoraria Akcea: Other: Accordant Health. Rossi:Janssen, Celgene, Amgen: Consultancy; BMS: Research Funding. Niesvizky:Takeda, Amgen, BMS, Janssen, Celgene: Consultancy, Research Funding.

Background: Light chain (AL) amyloidosis is characterized by deposition of misfolded monoclonal immunoglobulin light chains leading to organ dysfunction. AL amyloidosis has traditionally been treated with agents used in multiple myeloma, primarily alkylators, proteasome inhibitors (PIs), immunomodulatory agents (IMiDs), and high-dose melphalan/autologous stem cell transplantation (ASCT). A retrospective study comparing patients with AL amyloidosis who underwent ASCT as frontline therapy ('upfront ASCT') to those undergoing ASCT following induction ('deferred ASCT') revealed that deferred ASCT was associated with prolonged overall survival (OS) compared to upfront ASCT (Afrough et al, Biol Blood Marrow Transplant, 2018). Given the number of effective new therapies for AL amyloidosis, the potential to delay ASCT after one or more lines of therapy ('salvage ASCT') is feasible. To our knowledge, transplant outcomes of AL amyloidosis patients undergoing deferred vs salvage ASCT following at least one relapse have not been reported. A retrospective chart review was conducted to compare AL amyloidosis patients receiving deferred vs salvage ASCT for progression-free survival (PFS) and overall survival (OS). The study was approved by the Institutional Review Board at Weill Cornell Medical College. Methods: Twenty-four patients with AL amyloidosis who underwent deferred or salvage ASCT between 2000-2018 were included in the analysis. Patients who underwent upfront ASCT without induction chemotherapy were excluded. Demographics and clinical parameters were extracted from the electronic medical record. PFS was calculated from date of ASCT to first relapse and OS was calculated both from date of diagnosis and date of ASCT to death. Patients were censored if lost to follow-up prior to experiencing the relevant event. PFS as well as OS of patients who underwent deferred vs salvage ASCT were compared. Log-rank tests were used to statistically evaluate differences between Kaplan-Meier PFS/OS curves. Cox proportional hazards models were used to calculate hazard ratios (HR) using deferred ASCT as the reference treatment. Results: Among the 24 patients included in this analysis, 13 underwent deferred ASCT with 1 prior line of chemotherapy (e.g., induction), and 11 underwent salvage ASCT with a median of 3 prior lines (Table 1). Ten patients had cardiac amyloidosis, 15 had renal amyloidosis, and 6 had multi-organ involvement. Induction regimens received in the deferred group are included in Table 1. Neither PFS nor OS was significantly different between patients receiving deferred vs salvage ASCT. After median follow-up of 2.9 years, median PFS in patients who received deferred ASCT was 6.5 years and not reached in those who received salvage ASCT (P=0.47), with a HR of 1.74 (95% CI, 0.38-7.85) (Figure 1A). Median OS from date of ASCT was not reached in either group after a median follow-up of 2.8 years (P=0.52), with a HR of 2.16 (95% CI, 0.19-24.04) (Figure 1B). Similarly, median OS calculated from date of diagnosis was not significantly different between deferred vs salvage ASCT (P=0.79) (Figure 1C). Conclusions: In this cohort of 24 AL amyloidosis patients, no significant differences in PFS or OS were seen between patients undergoing deferred ASCT following induction vs salvage ASCT following multiple lines of therapy. Unlike the superior OS seen with deferred vs upfront ASCT, our findings show that either deferred or salvage ASCT may be associated with comparable outcomes and suggest similar OS despite timing of transplant. However, it is important to note the small sample size and that none of our patients received daratumumab-based regimens which may have improved PFS/OS in either or both groups. There were also small differences between groups in use of maintenance (1 vs 3 patients in the deferred and salvage groups, respectively) and proportion of patients receiving higher doses of melphalan 200mg/m2 vs 140 mg/m2 (69% vs 55% in deferred and salvage groups, respectively). Nevertheless, the lack of difference seen in PFS and OS between the two groups suggests that eventual hematologic relapse and organ progression with death occur at similar time intervals despite timing of ASCT. This speaks to the point that in newly diagnosed AL amyloidosis as well as later in the disease, achieving deep responses to prevent organ progression and death regardless of timing of ASCT remains an important treatment goal. Disclosures Van Besien: Miltenyi Biotec: Research Funding. Coleman:Kite Pharmaceuticals: Equity Ownership; Pharmacyclics: Speakers Bureau; Merck: Research Funding; Gilead, Bayer, Celgene: Consultancy, Research Funding, Speakers Bureau. Niesvizky:Takeda, Amgen, BMS, Janssen, Celgene: Consultancy, Research Funding. Rosenbaum:Janssen: Research Funding; Honoraria Akcea: Other: Accordant Health.

Introduction: Predictors routinely used to assess long-term survival after allogeneic hematopoietic cell transplantation (alloHCT) have not been specifically validated for pre-transplant risk assessment of patients getting cord blood transplantation supported by Haplo-CD34+ Progenitor cells as a myeloid bridge (haplo-cord). Methods: All consecutive adult patients with hematological malignancies who received an alternative donor alloHCT with a haplo-cord at Weill Cornell Medicine were included. Data was collected from an ongoing haplo-cord protocol (clinicaltrials.gov identifier 01810588). Plasma cell disorders were excluded. Age, CIBMTR Disease Risk Index (DRI), Karnofsky performance score (KPS), and HCT comorbidity index (HCT-CI) (routinely calculated since 06/2014), were assessed before alloHCT. The Kaplan-Meier method was used to estimate OS probabilities. Comparisons of OS were evaluated by the log-rank test. Significant predictors were considered in a Cox proportional hazards regression model using forward stepwise selection. A cumulative incidence function (CI) for relapse was calculated using a competing risk model for non-relapse mortality (NRM). We further validated our findings in the subgroup of patients with AML. Results: Between 06/2012 and 12/2018, 217 patients underwent haplo-cord transplantation. Indications for alloHCT included: 66% leukemia, 19% MDS/MPN, 15% Lymphoma. Median age was 58 yr (22% ≤ 40yrs, 33% between 41-59yrs, and 45% ≥ 60 yrs). 43% of patients were women. KPS score was ≥ 90 in 56%. DRI was high/very-high in 43% and low/intermediate in 56%. HCT-CI for 154 patients was 0 in 14%, 1-2 in 21%, 3-5 in 45% and ≥ 6 in 20%. Conditioning regimens included fludarabine with melphalan 45%, plus TBI 51%, other 4%. Median follow-up was 30 months. 2yr OS was 38% (95%CI 31-44%). 2yr CI of NRM was 35% and relapse 36%. Age (p=0.001), DRI (p Conclusion: DRI and age are highly predictive of OS for patients undergoing haplo-cord transplantation. Our finding that HCT-CI is not predictive of OS when applied to haplo-cord alloHCT is supported by previous findings investigating the role of HCT-CI in cohorts with cord blood donors (Adachi Y et al BBMT 2018 and Majhail N et al BBMT 2008). To this end, our findings demonstrate that a high HCT-CI score should not preclude patients from evaluation for alternative donor transplantation using cord blood supported by Haplo-CD34+ progenitor cells. Other prognostic tools to assess specific comorbidities impacting this transplant platform are needed for accurate pre-transplant risk assessment in order to improve decision making and clinical trial assignments. Disclosures Van Besien: Miltenyi Biotec: Research Funding.

Background: Renal impairment is a frequent complication of multiple myeloma (MM) associated with poor prognosis and decreased overall survival; and can complicate drug dosing, limit treatment options and lead to a higher incidence of adverse events. Daratumumab is an anti-CD38 monoclonal antibody indicated for the treatment of patients with MM which does not require dose modification in the setting of renal impairment. Real-world data regarding its efficacy in patients with renal impairment and the rate of renal response are lacking. Methods: We performed a retrospective, single-center analysis of patients with relapsed/refractory MM treated with daratumumab as monotherapy or in combination with novel agents. Patients were grouped by renal function as calculated by their eGFR using the MDRD equation: =60 mL/min/1.73m2. Renal response was defined as an eGFR >= 60 in two consecutive visits for patients with baseline renal impairment. Results: We identified 91 patients who started treatment with daratumumab between 2015-06-11 and 2018-08-16. The median age was 69 years old (range 40-93) and 25% were over the age of 75; 49 patients (54%) were female. Six patients (9%) were Hispanic, 16 (20%) were African American and 57 (71%) were Caucasian. High-risk cytogenetics were present in 58% of patients; defined as the presence of a complex karyotype, 1q gain, t(4;14), t(14;16), t(14;20) or del17p. Patients underwent a median of 5 prior lines of therapy (range 1-13), 45% had received an autologous stem cell transplant, 91% had been exposed to an immunomodulatory agent, 96% to a proteasome inhibitor, and 89% to both. Upon initial treatment, 53 patients (58%) had an eGFR >=60 mL/min/1.73m2, while 27 (30%) and 11 (12%) patients had an eGFR of 30-59 and Discussion: The results of this analysis provide comparable efficacy - independent of the degree of baseline renal impairment - to the results seen in clinical trials of combination therapy with daratumumab. Furthermore, the high renal response rate (29%) seen, as compared to the one in the subgroup analysis of ENDEAVOR (15%), highlights the utility of daratumumab in reversing renal end-organ damage in patients with relapsed/refractory MM without an increase in adverse events compared to patients with preserved renal function. These results suggest that daratumumab may be able to abrogate the adverse prognostic factor that impaired baseline renal function portends. A limitation of this study is its retrospective nature, the confounding effect of concurrent myeloma therapy and the small number of patients included with renal impairment. Table Disclosures Coleman: Merck: Research Funding; Pharmacyclics: Speakers Bureau; Kite Pharmaceuticals: Equity Ownership; Gilead, Bayer, Celgene: Consultancy, Research Funding, Speakers Bureau. Niesvizky:Takeda, Amgen, BMS, Janssen, Celgene: Consultancy, Research Funding. Rossi:Janssen, Celgene, Amgen: Consultancy; BMS: Research Funding.

Introduction: Haplo-cord transplantation - the co-infusion of a single umbilical cord graft with CD34-selected cells from a haplo-identical donor, offers an alternative stem cell source for patients lacking HLA-matched donors. The T-cell depleted haplo-graft acts as a myeloid bridge until replaced by durable cord hematopoiesis. Anti-thymocyte globulin (ATG) is routinely used in haplo-cord preparative regimens to reduce graft failure, graft vs. host disease (GVHD) and graft vs. graft reactions. ATG depletes T-lymphocytes through Fas-mediated apoptosis, but also indirectly stimulates T-cell destruction through antibody-dependent cellular phagocytosis (ADCP) and antibody-dependent cellular cytotoxicity (ADCC) (de Koning, Blood Adv. 2018). Excessive depletion of cord lymphocytes may compromise immune reconstitution and graft vs. tumor effects. G-CSF administration early post-transplant may sensitize cord lymphocytes to the cytotoxic effects of residual ATG. G-CSF drives myeloid precursor proliferation and activates phagocytosis, facilitating increased ADCP and ADCC of ATG-coated cells (de Koning, Blood Adv, 2018). Prior to the publication of this data, our institutional practice was to administer G-CSF to haplo-cord transplant recipients from day +6 until neutrophil engraftment. In April 2018, we altered our practice - withholding routine G-CSF treatment. We here compare our transplant outcomes 1 year before and after this practice shift. Methods: We examined consecutive adult patients with hematologic malignancy that underwent haplo-cord transplantation conditioned with fludarabine and melphalan with or without total body irradiation (400 cGy) at Weill Cornell Medicine, between 04/2017 and 04/2019. All patients received rabbit ATG (Thymoglobulin) 1.5 mg/kg on days -5, -3 and -1 (total dose 4.5 mg/kg). Data was collected as part of study 01810588 registered at clinicaltrials.gov. Probabilities of relapse, relapse-related mortality (RRM) and non-relapse mortality (NRM) were generated using cumulative incidence (CI) estimates to accommodate competing risks. Probabilities of overall survival (OS) and progression-free survival (PFS) were calculated using Kaplan-Meier estimates and inter-group comparison performed by log-rank testing. Variables with potential survival impact were evaluated in a Cox proportional hazards regression model. Results: The study included 59 haplo-cord recipients - 30 who received G-CSF (GCSF group) and 29 who did not (NO GCSF group). Groups were well matched for age, weight, disease, DRI, baseline lymphocyte count, CMV recipient/donor status and TBI treatment (Table). Neutrophil engraftment occurred at a median of 10 days in the GCSF group vs. 14 days in the NO GCSF group (p=0.0002), and platelet recovery at a median of 20 and 22 days (p=-0.61). Primary graft failure occurred in 1 GCSF patient and 2 NO GCSF patients (p=0.53). The incidence of acute GVHD (grade II-IV) by day 100 was 10% in both groups (p=0.97). There was no significant difference between GCSF and NO GCSF in the CIs of relapse, RRM or NRM at 1yr. No difference was found in 1yr OS or PFS on univariate analysis (Table). After adjusting for patient age, weight, lymphocyte count prior to ATG, disease subtype, CIBMTR disease risk index (DRI), Karnofsky performance status (KPS), comorbidity score and TBI exposure, in multivariate analysis, no effect on OS or PFS was observed. CMV reactivation was observed in 40% (GCSF) vs. 21% (NO GCSF) (p=0.11). The trend towards lower reactivations in the NO GCSF may in part be due to the introduction of letermovir prophylaxis for CMV positive transplant recipients in 02/2018. Acknowledging the limited follow up of NO GCSF patients, we note a trend towards improved CD4 counts at 1yr in this group - median 271 cells/μL (n=6, IQR25-75 = 240-342) vs. 155 cells/μL in the GCSF group (n=16, IQR25-75 = 111-473) (p=0.17). Conclusion: Our data shows that G-CSF can safely be eliminated from haplo-cord transplant. We see a delay in neutrophil engraftment but no adverse effect on early morbidity or mortality outcomes. We continue to withhold early G-CSF while assessing long-term outcomes. Longer follow-up is needed in our cohort to enable a systematic analysis of immune reconstitution. Early CD4+ cell recovery after ATG treatment has been shown to improve OS, PFS, NRM and RRM (Admiraal, Lancet Hem 2015 & 2017). Disclosures Van Besien: Miltenyi Biotec: Research Funding.

Autologous stem cell transplantation (ASCT) conditioned with high-dose chemotherapy has long been established as the standard of care for eligible patients with newly diagnosed multiple myeloma. Despite recent therapeutic advances, high-dose melphalan (HDM) remains the chemotherapy regimen of choice in this setting. Lenalidomide (LEN) in combination with low-dose dexamethasone is recognized as a standard of care for patients with relapsed or refractory multiple myeloma (RRMM), and there is growing support for the administration of LEN as maintenance therapy post-ASCT. In view of the above, the present phase I clinical trial was designed to evaluate the safety and tolerability of high-dose LEN (HDLEN) in patients with RRMM, and to determine the maximum tolerated dose of HDLEN when added to HDM before ASCT. Despite administering HDLEN at doses of up to 350 mg/day, the maximum tolerated dose could not be determined, owing to an insufficient number of dose-limiting toxicities in the 21 patients enrolled in the trial. Conditioning with HDLEN plus HDM was associated with a favorable tolerability profile. Adverse events following ASCT were as expected with HDM. Median progression-free and overall survival were 10 months and 22 months, respectively, in this population of heavily pretreated patients. Our findings suggest that HDLEN in combination with HDM may offer significant potential as a conditioning regimen before ASCT in patients with RRMM. These preliminary findings are now being evaluated further in an ongoing phase II clinical trial.

Introduction: Umbilical cord blood (UCB) transplant supported by third party CD34-selected cells results in rapid count recovery, UCB mediated GVL effects and low rates of chronic GvHD. For patients lacking haplo-identical relatives, other sources of CD34 progenitors are needed. Methods: We identified partially matched unrelated donors for patients lacking suitable haplo-identical donors -including second-degree relatives - and who otherwise were candidates for haplo-cord transplant. Most were treated on prospective studies (clinicaltrials.gov 00943800 and 01810588). For 5 patients, UCB were obtained through NCT01351545. Results: Between 12/2014 to 7/2018 of 126 candidates for haplo-cord transplant, 26 (21%) had no suitable related donor. Most common reasons were: no first or second degree partially matched donors, ill or unavailable relative, high titers of HLA-antibodies against all relatives, or evidence of hematological familial hereditary syndrome. Diagnoses were: 16 AML/MDS, 5 ALL, 2 MPN, 1 NHL, 1 plasma cell leukemia and 1 SAA. Median age was 57 (24-75). 50% were women. 42% non-Hispanic white (NHW), 19% non-Hispanic blacks (NHB), 19% Hispanic, 8% other minorities. CIBMTR Disease Risk Index (DRI): 46% intermediate, 38% high and 8% very high. Median HCT-CI was 3.5 (25%-75% IQR 2-6). Conditioning: 16 Flu/Mel/TBI (94% 400cGray), 8 Flu/Mel,1 Flu/Cy, 1 Etoposide/TBI. All except 1 received ATG 4.5 mg/kg and all received post-transplant Tacrolimus and MMF. UCB matching was 4/8, 5/8, 6/8 or 7/8 HLA in 12%, 27%, 23%, and 38%, respectively. HLA matching for unrelated haplos was 5-6/12, 7-8/12, >9/ 12 HLA in 15%, 54% and 19%, respectively. For UCB, median cells collected were 2.1 (range1.1-4.0) ×107 TNC/kg. CD34 cell dose of unrelated donor graft was 3-5 ×106 CD34/kg. Median time to ANC engraftment was 11 days (range 9-35) and platelet engraftment was 18 days (range11-124). Chimerism on day 56 are shown in figure 1. There were three patients with graft failures: Pt #5 with complete graft rejection, autologous reconstitution, but ongoing clinical remission that persists to date (Day+ 1223); Pt #13 with graft failure and subsequent relapse, rescued with second UCB HSCT but died of progression of disease; and pt #18 who died from infectious complications after graft failure. Acute GvHD occurred in 35% of patients (4 Grade I-II, 4 Grade III, and 1 Grade IV). cGvHD was rare: One patient with mild severity and a second with severe lung involvement. After a median follow up of 209 days, 6 months cumulative incidence of relapse (CIR) was 16% and non-relapse mortality (NRM) was 20%. Median OS was 14 months (95%CI 7-27). Conclusion: 20% of adults without matched related or unrelated donors, also lack suitable first or second degree haplo-identical donors. UCB transplant with partially matched unrelated donor accessory cells provides an alternative for transplantation. Engraftment is rapid, rates of acute GVHD are acceptable and incidence of chronic GVHD is very low. Prolonged survival is encouraging in this patient cohort with adverse characteristics and who would not be candidate for haplo-identical HSCT. Disclosures No relevant conflicts of interest to declare.

Background: Increased baseline white blood cell count (WBC) has been associated with vaso-occlusive complications in sickle cell disease (SCD), raising concern for the use of mobilizing agents that increase WBC count for hematopoietic progenitor cell (HPC) collection for gene therapy. Indeed, G-CSF, which predominantly increases neutrophil counts, when administered to SCD patients can precipitate life-threatening vaso-occlusion. Such vaso-occlusion, however, does not always correlate with degree of white blood cell count elevation (Fitzhugh C et al, Cytotherapy 2009) and G-CSF is associated with increases in neutrophil activation and adhesion. This raises the question whether WBC might be a surrogate for other proposed contributors to vaso-occlusion, such as activation of white cells, platelets, and coagulation. We examined this issue in the context of a clinical study of HPC mobilization with a single dose of plerixafor alone in clinically stable SCD patients. Materials and Methods: 14 patients (13 SS, 1 SB0, median age 31 with range 21-46) have completed the study so far (6 patients at 80 ug/kg, 3 patients at 160 ug/kg, and 5 patients at 240 ug/kg). 10 patients were on hydroxyurea (HU) at a median dose of 25 mg/kg (range 16-28 mg/kg) with a mean HbF of 17% versus 7% for the non-HU treated patients. Only one patient (non-HU treated) had received recent red cell transfusion (for leg ulcers) and had HbA (54%) present. Whole blood was collected at means of 4 hr pre-dose and 12 hr post-dose for activation marker studies by flow cytometry (cell studies) or ELISA (coagulation studies) as listed in Table 1. Results: Increases in absolute total white cell, neutrophil, monocyte, and lymphocyte concentrations in whole blood with plerixafor treatment were all highly significant (Table 2, p < 0.002), without significant differences between HU- and non-HU treated patients or between dose levels. Twelve of 14 patients, however, did not experience any significant adverse events from plerixafor administration. Absolute neutrophil counts (ANC) were strongly correlated with absolute concentrations (but not percentages) of activated β2 integrin neutrophils (r= 1.0) and activated Mac-1 neutrophils (r= 0.8) but no other activation markers. We observed significant plerixafor-associated increases in activation markers (Figure 1) only for ANC subsets positive for activated β2 integrin (1.7± 0.44 fold, mean ± SD, p=0.002) and activated Mac-1 (1.7 ± 1.2 fold, p=0.05), which the correlations with ANC partly explain. The activated Mac-1 significance, however, disappeared with Bonferroni correction. There were no significant differences in activation markers between dose levels or between HU- and non-HU treated patients. There were moderate correlations between activated β2 integrin or activated Mac-1 and absolute reticulocyte count (r= 0.6 for both) and HbF (r= -0.5 for both) but not between these activation markers and LDH. Two patients had pain crises starting at 48 hr (80 ug/kg dose) and 81 hr (240 ug/kg dose) post-plerixafor administration; their pre and post-dose (12 hr) white counts are shown in Table 3. The fold-increase in activation markers for these 2 patients is summarized in Figure 2 (for each activation marker, color-coded arrows point to the two patients) Conclusion: As with G-CSF, elevation of WBC or their subsets with plerixafor is not necessarily associated with vaso-occlusion, as manifested by pain crises. In our study, however, ANC elevation correlated with absolute concentrations of neutrophils positive for activated β2 integrin and activated Mac-1, which were the only activation markers significantly increased with plerixafor. These activation markers in turn correlated with reticulocyte count and HbF, which influence SCD vaso-occlusive severity. Vaso-occlusion as manifested by pain crises, however, was not consistently associated with the highest fold increases in ANC or activation markers. Therefore it remains unclear which bioassays correlate with vaso-occlusion associated with plerixafor mobilization. Disclosures No relevant conflicts of interest to declare.

number of patients and longer follow-up are needed to confirm these results and to evaluate the long-term outcome.