scholarly journals Clinical Outcomes after Allogeneic Hematopoietic Stem Cell Transplantation in Patients with Transfusion-Dependent β-Thalassemia Treated at the Bambino Gesù Children's Hospital, Rome, Italy

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 969-969
Author(s):  
Pietro Merli ◽  
Annalisa Ruggeri ◽  
Mattia Algeri ◽  
Giuseppina Li Pira ◽  
Giulia Ceglie ◽  
...  

β-thalassemia is one of the most common monogenic blood disorders worldwide, and is highly prevalent in Mediterranean countries. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has been the only curative treatment for transfusion-dependent β-thalassemia (TDT; the most severe disease form) for many years, but it is limited by donor availability and has a significant risk of morbidity and mortality. We conducted a chart review of patients with β-thalassemia who underwent allo-HSCT (N=80) at the Bambino Gesù Children's Hospital, Rome, Italy, between March 2011 and August 2018. Median (range) age at allo-HSCT was 5.5 (0.3-20.0) years [<12 years: n=70 (87.5%), ≥12-18 years: n=7 (8.8%), ≥18 years: n=3 (3.8%)] and all patients but one had TDT [n=79 (98.8%)]. Prior to allo-HSCT, patients received a median (range) of 17.4 (4-52) transfusions per year (n=64) and had a median (range) serum ferritin concentration of 1217 (135-9123) ng/mL and a median (interquartile range) hemoglobin level of 10.3 (9.3-11.4) g/dL. All patients had received regular iron chelation therapy prior to transplantation. In total, 18 (22.5%), 28 (35.0%), and 34 (42.5%) patients received allo-HSCT from human leukocyte antigen (HLA)-identical sibling donors, HLA-haploidentical donors, and unrelated donors (fully matched donor: n=28, donor with a single HLA disparity: n=6), respectively. Of these donors, 42 (52.5%) were carriers for thalassemia-associated mutations. In total, 53 (66.3%) donors and 35 (43.8%) recipients were cytomegalovirus-positive. Bone marrow was the stem cell source in 51 cases (63.8%), while 28 patients received an alphabeta T-cell depleted peripheral blood haploidentical HSCT (35.0%); the remaining child (1.3%) received both bone marrow and cord blood from the same related donor. All patients continued to receive transfusions immediately after allo-HSCT; however, only 7 (8.8%) received a transfusion in the 3 to 12-month post-transplantation period (2 due to underlying disease; 5 due to other reasons including GI bleeding). Median (range) time to reach transfusion-free status was 3.8 (1.1-47.8) weeks. Median (interquartile range) hemoglobin levels at 6 and 12 months after allo-HSCT were 10.9 (10.2-11.9) and 11.9 (10.6-13.0) g/dL, respectively. The cumulative incidences of primary and secondary graft failure were 10.0% and 12.5% at 24 months (HLA-identical donor: 0% and 11.1%, haploidentical donor: 17.9% and 3.6%, unrelated donor: 8.8% and 20.6%). Eleven out of 14 patients experiencing graft failure were successfully rescued with a second allograft, while 2 patients were not retransplanted due to parental decision and 1 patient died after the engraftment of the second allograft. Eight patients developed grade II-IV acute graft-versus-host disease (GVHD) and one patient developed moderate chronic GVHD. Cumulative incidence rates of grades II-IV and III-IV acute GVHD were 12.7% and 8.0% at 24 months (HLA-identical donor: 0% and 0%, haploidentical donor: 7.3% and 0%, unrelated donor: 23.8% and 18.8%). Three patients (3.8%) died of transplant-related causes (1 case each of hemophagocytic lymphohistiocytosis, sepsis, and multi-organ failure [the patient receiving the second allograft]) with a median (range) time from transplantation to death of 8.7 (3.7-11.0) months. Of these patients, all had been transplanted from an unrelated donor and 2 had reached sustained full-donor chimerism. The probability of overall and event-free (event defined as either death or primary/secondary graft failure) survival was 96.2% and 81.2% at 24 months (HLA-identical sibling donor: 100% and 88.9%, haploidentical donor: 100% and 78.6%, unrelated donor: 91.2% and 79.4%). The probability of thalassemia-free survival (event defined as either death or primary/secondary graft failure not rescued by a second allograft) was 93.7% at 24 months (HLA-identical sibling donor: 100%, haploidentical donor: 92.9%, unrelated donor: 91.2%). In this large single-center cohort of children with predominantly TDT, allo-HSCT led to beneficial outcomes for most patients, resulting in the discontinuation of transfusions with 93.7% of patients being thalassemia-free. Nevertheless, HSCT is still associated with GVHD, graft failure, and mortality, and only 22.5% of patients had an HLA-identical sibling donor, illustrating a key limitation of allo-HSCT. Emerging research is addressing such barriers to treatment. Disclosures Merli: Novartis: Honoraria; Sobi: Consultancy; Amgen: Honoraria; Bellicum: Consultancy. Algeri:Miltenyi: Honoraria; Atara Biotherapeutics: Consultancy, Honoraria; Bluebird bio: Consultancy, Honoraria. Gruppioni:Bluebird bio: Employment, Equity Ownership. Kommera:Bluebird bio: Employment, Equity Ownership. Maa:Bluebird bio: Employment, Equity Ownership. Locatelli:Bellicum: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; bluebird bio: Consultancy; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Miltenyi: Honoraria.

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3199-3199
Author(s):  
Ji Zha ◽  
Lori Kunselman ◽  
Hongbo Michael Xie ◽  
Brian Ennis ◽  
Jian-Meng Fan ◽  
...  

Hematopoietic stem cell (HSC) transplantation (HSCT) is required for curative therapy for patients with high-risk hematologic malignancies, and a number of non-malignant disorders including inherited bone marrow failure syndromes (iBMFS). Strategies to enhance bone marrow (BM) niche capacity to engraft donor HSC have the potential to improve HSCT outcome by decreasing graft failure rates and enabling reduction in conditioning intensity and regimen-associated complications. Several studies in animal models of iBMFS have demonstrated that BM niche dysfunction contributes to both the pathogenesis of iBMFS, as well as impaired graft function after HSCT. We hypothesize that such iBMFS mouse models are useful tools for discovering targetable niche elements critical for donor engraftment after HSCT. Here, we report the development of a novel mouse model of Shwachman-Diamond Syndrome (SDS) driven by conditional Sbds deletion, which demonstrates profound impairment of healthy donor hematopoietic engraftment after HSCT due to pathway-specific dysfunctional signaling within SBDS-deficient recipient niches. We first attempted to delete Sbds specifically in mature osteoblasts by crossing Sbdsfl/flmice with Col1a1Cre+mice. However, the Col1a1CreSbdsExc progenies are embryonic lethal at E12-E15 stage due to developmental musculoskeletal abnormalities. Alternatively, we generated an inducible SDS mouse model by crossing Sbdsfl/flmice with Mx1Cre+ mice, and inducing Sbds deletion in Mx1-inducible BM hematopoietic and osteolineage niche cells by polyinosinic-polycytidilic acid (pIpC) administration. Compared with Sbdsfl/flcontrols, Mx1CreSbdsExc mice develop significantly decreased platelet counts, an inverted peripheral blood myeloid/lymphoid cell ratio, and reduced long-term HSC within BM, consistent with stress hematopoiesis seen in BMF and myelodysplastic syndromes. To assess whether inducible SBDS deficiency impacts niche function to engraft donor HSC, we transplanted GFP+ wildtype donor BM into pIpC-treated Mx1CreSbdsExc mice and Sbdsfl/flcontrols after 1100 cGy of total body irradiation (TBI). Following transplantation, Mx1CreSbdsExc recipient mice exhibit significantly higher mortality than controls (Figure 1). The decreased survival was related to primary graft failure, as Mx1CreSbdsExc mice exhibit persistent BM aplasia after HSCT and decreased GFP+ reconstitution in competitive secondary transplantation assays. We next sought to identify the molecular and cellular defects within BM niche cells that contribute to the engraftment deficits in SBDS-deficient mice. We performed RNA-seq analysis on the BM stromal cells from irradiated Mx1CreSbdsExc mice versus controls, and the results revealed that SBDS deficiency in BM niche cells caused disrupted gene expression within osteoclast differentiation, FcγR-mediated phagocytosis, and VEGF signaling pathways. Multiplex ELISA assays showed that the BM niche of irradiated Mx1CreSbdsExc mice expresses lower levels of CXCL12, P-selectin and IGF-1, along with higher levels of G-CSF, CCL3, osteopontin and CCL9 than controls. Together, these results suggest that poor donor HSC engraftment in SBDS-deficient mice is likely caused by alterations in niche-mediated donor HSC homing/retention, bone metabolism, host monocyte survival, signaling within IGF-1 and VEGF pathways, and an increased inflammatory state within BM niches. Moreover, flow cytometry analysis showed that compared to controls, the BM niche of irradiated Mx1CreSbdsExc mice contained far fewer megakaryocytes, a hematopoietic cell component of BM niches that we previously demonstrated to be critical in promoting osteoblastic niche expansion and donor HSC engraftment. Taken together, our data demonstrated that SBDS deficiency in BM niches results in reduced capacity to engraft donor HSC. We have identified multiple molecular and cellular defects in the SBDS-deficient niche contributing to this phenotype. Such niche signaling pathway-specific deficits implicate these pathways as critical for donor engraftment during HSCT, and suggest their potential role as targets of therapeutic approaches to enhance donor engraftment and improve HSCT outcome in any condition for which HSCT is required for cure. Disclosures Olson: Merck: Membership on an entity's Board of Directors or advisory committees; Bluebird Bio: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Miltenyi: Honoraria.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3273-3273
Author(s):  
Swati Naik ◽  
Olive S. Eckstein ◽  
Ghadir Sasa ◽  
Robert A. Krance ◽  
Carl E. Allen ◽  
...  

Introduction: Hematopoietic stem cell transplantation (HSCT) for patients with hemophagocytic lymphohistiocytosis (HLH) following myeloablative conditioning regimens (MAC) is associated with high rates of non-relapse mortality. A previously reported prospective, phase 2 multi-center trial (RICHI) using using RIC strategy of fludarabine, melphalan and alemtuzumab (day -14) for HLH and primary immune deficiency syndromes (PIDS) demonstrated improved mortality rates but fewer than half the patients with HLH (41%) successfully engrafted without secondary graft failure, need for donor lymphocyte infusion (DLI) or second transplant. Incorporation of thiotepa during conditioning has been to shown to be safe and improve engraftment. We report the results of a retrospective analysis of nine consecutive patient treated with the inclusion of thiotepa into the RICHI backbone (RICHI+TT). Methods: Patients received a single additional dose of thiotepa 10mg/kg on day -3 added to the fludarabine/melphalan/alemtuzumab backbone (RICHI+TT) with the same graft-versus-host disease prophylaxis of methyprednisolone through day +28 and cyclosporine through day 180. To determine sustained engraftment, we used the same parameters the RICHI study defined as > 5 % donor chimerism without any intervention and alive at 1 year post-transplant. Results: Our cohort consisted of 8 males and 1 female with a median age of 7 years (range 1-18 years). Seven patients had HLH with proven pathogenic genetic mutations (biallelic PRF1 - 2, UNC13D - 2, STXBP1- 1, RAB27A-1, STAT3 gain of function-1), while the other 2 patients had HLH without identified pathogenic mutations (1- chronic active EBV, 1- juvenile idiopathic arthritis with refractory macrophage activation syndrome).The majority of patients received a bone marrow product (n = 8), one patient received a peripheral blood stem cell product; 6 patients received a graft from a matched related donor , two from a mismatched unrelated donor, and one from a matched unrelated donor. All patients engrafted at a median of 15 days post-transplant (8 patients at 100% donor chimera; 1 patient at 99% donor chimera at initial engraftment). Six of the 9 patients were evaluable to assess donor chimerism at 1 year as per study definitions with a median follow up of 875 days (range: 366 -1000 days). All 6 patients had > 5% donor chimerism and were alive at 1 year. Five of the 6 evaluable patients met criteria for sustained donor engraftment without need for intervention and all maintained 100% donor chimerism at last follow-up (Table 1). Only one of the six patients had evidence of falling donor chimerism; this stabilized at 40% donor chimerism after DLI. No patients had primary or secondary graft failure. Three patients were not evaluable for long-term assessment due to death prior to 1 year. Six of the 9 patients described here are alive and disease-free with stable long-term engraftment. The incorporation of Thiotepa to the RICHI backbone improved on previously reported sustained donor engraftment (Table 2). Conclusions: The RICHI+TT approach had better long-term donor engraftment with a decreased need for DLI or second transplant without increased rates of non-relapse mortality. Prospective studies are needed to determine the optimal treatment strategies for patients with HLH who require HSCT for cure. Disclosures Heslop: Cell Medica: Research Funding; Tessa Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Marker Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Kiadis: Membership on an entity's Board of Directors or advisory committees; Allovir: Equity Ownership; Gilead Biosciences: Membership on an entity's Board of Directors or advisory committees.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2260-2260 ◽  
Author(s):  
Arnon Nagler ◽  
Avichai Shimoni ◽  
Irit Avivi ◽  
Jacob M. Rowe ◽  
Katia Beider ◽  
...  

Abstract Abstract 2260 Background: BKT140 is a high affinity CXCR4 inhibitor with an extended K off-rate. Pre-clinical studies in animal models with BKT140 showed a robust mobilization of white blood cells (WBC) and hematopoietic stem cells (HSC). Furthermore, BKT140 also showed a direct anti-tumor effect against human-derived multiple myeloma (MM), lymphoma and primary leukemia cells and cell lines in vitro and in vivo, causing significant apoptosis. Aims: To assess BKT140 toxicity (primary endpoints), the mobilization capacity of CD34+ hematopoietic progenitors and CD138 MM cells, and pharmacokinetic (PK) and pharmacodynamic (PD) (secondary endpoints). Methods: 16 MM patients in first CR/PR were included in a phase I/IIa study, in which escalating doses of BKT140 (30, 100,300,900 μg/kg) were administered together with a high-dose cyclophosphamide (Cy) (2 g/m2) and G-CSF (5 μg/Kg) for stem cell mobilization. G-CSF was started on day 5 post Cy and BKT140 was injected subcutaneously (SC) once on day 10. Toxicity, PK, and mobilization capacity (assessed by serial measurements of number of WBC and CD34+ and CD138+ cells) were measured pre- and post BKT140 administration. Results: BKT140 was well tolerated at all doses and none of the patients developed grade II-IV toxicity. BKT140 was rapidly absorbed with no observed lag time, with peak plasma concentrations occurring 0.5h after administration. Clearance was rapid, with a median terminal half-life of 0.69h. BKT140 administration resulted in a significant dose-dependent increase in the number of peripheral blood neutrophils, monocytes, lymphocytes, and CD34+ cells compared to the G-CSF/Cy individual patient baseline. The maximum increase in the number of WBC from baseline was observed within 8h following BKT140 injection, 2.5-, and 3.0-, 4.1- and 4.8-fold, for the 4 BKT140 doses, respectively. Furthermore, BKT140 administration resulted in a significant increase in the mean absolute PB CD34+ cells mobilized (6.6, 7.5, 11.2 and 20.6 ×106/kg) for the 4 BKT140 administered doses, respectively. Moreover, the number of aphaeresis was reduced from 2.25 procedures at the first two BKT140 doses to 1.25 and 1 aphaeresis at the highest BKT140 doses, respectively. An increase in the number of CD138+ cells was observed in 6 out of 6 pts that had CD138+ cells in their blood and were treated with lower doses of BKT140 (30 and 100 μg/kg). Interestingly, in pts that were treated with the highest doses of BKT140 (300 and 900 μg/kg) a reduced number of CD138+ cells was observed in 3 out of 7 pts that had CD138+ cells in their blood, whereas in 4 pts, an increase in the number of CD138+ cells was shown. Three pts who did not have CD138+ cells in their blood were not affected by BKT140. The BKT140 mobilized grafts were used for AutoSCT following 200 mg/m2 melphalan conditioning. Pts received an average of 5.3×106 CD34+ cells/kg. All transplanted pts rapidly engrafted (n=15). The median day for neutrophil (>500/mm3) and platelet (>20,000/mm3, >50,000/mm3,) was on day 11 (range, 0–13), day 11 (range, 0–14), and day 14 (range, 0–23), respectively. Conclusions: The current data suggests that BKT140 can safely be added to G-CSF-based harvesting regimens, can increase CD34+ cell mobilization and reduce the number of collection days. Furthermore, due to its ability to release MM cells from the bone marrow and stimulate their cell death, additional studies are warranted to further evaluate the effect of BKT140 as an anti-MM agent. Disclosures: Nagler: Biokine Therapeutics Ltd: Consultancy. Abraham: Biokine Therapeutics Ltd: Employment, Equity Ownership, Patents & Royalties. Wald: Biokine Therapeutics Ltd: Employment. Shaw: Biokine Therapeutics Ltd: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Eizenberg: Biokine Therapeutics Ltd: Employment, Equity Ownership, Patents & Royalties. Peled: Biokine Therapeutics Ltd: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 965-965 ◽  
Author(s):  
Anthony Stein ◽  
Max S. Topp ◽  
Nicola Goekbuget ◽  
Ralf C. Bargou ◽  
Hervé Dombret ◽  
...  

Abstract Introduction: Improvements in the therapeutic options available for adult relapsed/refractory (r/r) B-precursor ALL are required. Blinatumomab is an investigational bispecific T-cell engager (BiTE®) antibody construct that redirects cytotoxic T cells to lyse CD19-positive B cells. Based on encouraging clinical data from a small phase 2 study (Topp MS et al. J Clin Oncol. 2014;32(15s): abstract 7005), we conducted a large confirmatory open-label, single-arm, multicenter phase 2 study of blinatumomab in patients with r/r B-precursor ALL. The aim of the present analysis from this phase 2 study was to characterize those patients who proceeded to allogeneic hematopoietic stem cell transplantation (HSCT) after achieving complete remission (CR)/complete remission with partial hematologic recovery (CRh*) with blinatumomab treatment. Methods: Eligible patients (≥18 years) had Philadelphia chromosome-negative r/r B-precursor ALL with one of the following negative prognostic factors: primary refractory, 1st relapse within 12 months of 1st remission, relapse within 12 months of HSCT, or ≥2nd salvage. Blinatumomab was given by continuous IV infusion (4 weeks on/2 weeks off) for up to 5 cycles. The primary endpoint was CR/CRh* within the first 2 cycles. Secondary endpoints included overall survival (OS), relapse-free survival (RFS), HSCT realization rate, 100-day mortality following HSCT, and adverse events. Results: 189 patients with a median age (range) of 39 (18‒79) years were enrolled and received blinatumomab for a median (range) of 2 (1‒5) cycles. At enrollment, 74 (39%) patients had received ≥2 prior salvage therapies, 64 (34%) had received prior HSCT, and 105 (56%) had ≥75% bone marrow blasts. 43% (81/189) of patients achieved CR/CRh* within 2 cycles, with similar rates of remission observed in both the HSCT-naïve (42%; 52/125) and prior HSCT (45%; 29/64) groups. In total, 32/81 responders (CR, n=28 and CRh*, n=4) underwent HSCT during blinatumomab-induced remission, yielding a transplantation realization rate for blinatumomab responders of 40% (Table 1). 52% (27/52) of the HSCT-naïve patients and 17% (5/29) of patients who had received prior HSCT proceeded to on-study HSCT during blinatumomab-induced remission. These 32 transplants occurred after a median of 2 (1-5) cycles of therapy, with 11 (34%) patients receiving myeloablative conditioning pre-HSCT, 12 (38%) reduced intensity conditioning, and 9 (28%) unknown regimens. Twenty-two (69%) patients used unrelated donors (stem cells derived from blood, n=11; bone marrow, n=6; cord blood, n=5), 7 (22%) used related donors including 6 siblings (blood, n=5; bone marrow, n=1) and 1 haploidentical mother (blood), with 3 (9%) donor types and stem cell sources unknown. Six patients achieving CR/CRh* after 2 cycles of blinatumomab underwent HSCT but were not included in the transplantation realization rate of 40% due to receiving subsequent antineoplastic therapy before HSCT conditioning (Table 1). Among the 43 patients who achieved CR/CRh* within 2 cycles of blinatumomab treatment but never reached HSCT, 20 (47%) had undergone prior HSCT, 7 (16%) were ≥65 years, and 2 (5%) were ≥65 years and had received prior HSCT (Table 1). Figure 1 Figure 1. At the time of the primary analysis (data cut-off in October 2013), with median follow-up of 9.8 months, median (95% CI) OS for the 189 blinatumomab-treated patients was 6.1 (4.2‒7.5) months. When censoring for HSCT, median OS was 5.1 (4.1‒7.1) months; although the medians are slightly different, the curves with and without HSCT censoring largely overlap. Median RFS was 5.9 months with and without censoring for HSCT. Nine patients died at any time after HSCT, with 5 deaths due to infection, 3 due to disease progression, and 1 due to graft-versus-host disease (GvHD). Three of these deaths (2 infections and 1 GvHD) were within 100 days of HSCT. The 100-day post-HSCT mortality rate was 11%. Summary: This large phase 2 study demonstrated antileukemia activity of single-agent blinatumomab in heavily pretreated or aggressive r/r ALL, irrespective of prior HSCT. The data suggest that blinatumomab enables patients to reach HSCT, with 11% 100-day mortality post-HSCT. Two-thirds of patients who did not reach HSCT after responding to blinatumomab were either ≥65 years old or had received prior HSCT. Longer follow-up is required to assess the role of HSCT in patients achieving CR/CRh* after treatment with blinatumomab. Disclosures Stein: Amgen Inc.: Membership on an entity's Board of Directors or advisory committees. Off Label Use: This presentation will discuss the off-label use of blinatumomab, as this agent is not approved for use by the FDA, EMA or any other regulatory authorities.. Topp:Amgen Inc.: Honoraria, Membership on an entity's Board of Directors or advisory committees. Goekbuget:Amgen Inc.: Consultancy, Honoraria, Research Funding. Bargou:Amgen Inc.: Consultancy, Honoraria. Dombret:Amgen Inc.: Honoraria, Research Funding. Larson:Amgen Inc.: Consultancy, Research Funding. Rambaldi:Amgen Inc.: Consultancy. Zugmaier:Amgen Reseach (Munich) GmbH: Employment; Amgen Inc.: Equity Ownership. Jia:Amgen Inc.: Employment, Equity Ownership. Maniar:Amgen Inc.: Employment, Equity Ownership. Huber:Amgen Research (Munich) GmbH: Employment; Amgen Inc.: Equity Ownership. Nagorsen:Amgen Inc.: Employment, Equity Ownership, Related to blinatumomab Patents & Royalties. Kantarjian:Amgen Inc.: Research Funding; ARIAD: Research Funding; Pfizer: Research Funding.


Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. SCI-20-SCI-20
Author(s):  
Hiromitsu Nakauchi

Abstract Hematopoietic stem cells (HSCs) are maintained by a specialized bone marrow microenvironment (niche) and are largely quiescent during the steady-state conditions1. However, upon stimulation or transplantation, HSCs can expand and differentiate into any mature hematopoietic cell type. This ability of donor HSCs to reform a recipient's hematopoietic system is key to the success of HSC transplantation (HSCT). For donor HSCs to engraft, the recipient bone marrow niche must first be emptied via myeloablative irradiation or chemotherapy. However, myeloablative conditioning can cause severe complications and even mortality. As an alternative, we have recently developed a metabolic conditioning approach for HSCT. By screening the amino acid requirements of HSCs, we identified the essential amino acid valine as indispensable for the expansion and maintenance of HSCs2. Both mouse and human HSCs failed to expand when cultured in valine-restricted conditions. In mice fed a valine-restricted diet, HSC frequency fell dramatically within one week. Dietary valine restriction thereby emptied the mouse bone marrow niche and just a two-week diet afforded long-term donor-HSC engraftment without chemoirradiative myeloablation. We conclude that valine plays a critical role in HSC maintenance and suggest dietary valine restriction as a conditioning regimen that may reduce iatrogenic complications in HSCT. These findings, and recent efforts to optimize this metabolic conditioning approach through mechanistic understanding of the HSC valine dependency, will be presented. Sudo K, Ema H, Morita Y, Nakauchi H. Age-associated characteristics of murine hematopoietic stem cells. J Exp Med. 2000;192:1273-1280.Taya Y, Ota Y, Wilkinson AC, et al. Depleting dietary valine permits nonmyeloablative mouse hematopoietic stem cell transplantation. Science. 354:1152-1155. Disclosures Nakauchi: ReproCELL Inc: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Megakaryon Inc: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; iBUKI Corp: Equity Ownership; iCELL Inc: Equity Ownership; Advanced Immunothearpy Inc: Equity Ownership.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 863-863 ◽  
Author(s):  
Robert M. Rifkin ◽  
Jason M. Melear ◽  
Edward Faber ◽  
William I. Bensinger ◽  
John M Burke ◽  
...  

Background: DARA, a human IgGκ monoclonal antibody targeting CD38, is approved in combination with bortezomib, melphalan, and prednisone (VMP) and bortezomib and dexamethasone (Vd) for newly diagnosed MM (NDMM) and relapsed MM (RMM), respectively. CyBorD is a commonly used immunomodulatory drug-sparing regimen for MM. In the LYRA (NCT02951819) study, DARA plus CyBorD (DARA-CyBorD) demonstrated efficacy and a tolerable safety profile at the end of induction. Here, we present updated findings examining the effect of monthly DARA maintenance on the efficacy and safety of DARA-CyBorD in NDMM and RMM. Methods: LYRA is an ongoing, single-arm, open-label, phase 2 study conducted at US community oncology centers. Patients (pts) were aged ≥18 years with documented MM per IMWG criteria, an ECOG performance score (PS) of 0-2, and ≤1 prior line of therapy. Pts received 4-8 induction cycles of DARA-CyBorD (cyclophosphamide 300 mg/m2 PO on Days 1, 8, 15, and 22; bortezomib 1.5 mg/m2 SC on Days 1, 8, and 15; and dexamethasone 40 mg PO or IV weekly [qw]) every 28 days. DARA was given at 8 mg/kg IV on Days 1 and 2 of C1, 16 mg/kg qw from C1D8 through C2, 16 mg/kg q2w for C3-6, and 16 mg/kg q4w for C7-8. After induction, eligible pts could undergo autologous stem cell transplantation (ASCT). All pts received up to 12 maintenance cycles with DARA 16 mg/kg IV q4w. Results: A total of 101 (87 NDMM, 14 RMM) pts were enrolled; 100 (86 NDMM, 14 RMM) pts received ≥1 treatment dose. Median age was 63 years; most pts were white (81%), male (64%), had ECOG PS 0-1 (94%) and had IgG (57%) MM; 36% of pts had high cytogenetic risk, defined as a del(17p), t(4:14) or t(14;16) abnormality. NDMM and RMM pts received a median of 6 and 8 cycles, respectively, of induction therapy. Thirty-nine NDMM pts and 1 RMM pt underwent ASCT. Fifty percent of pts received plerixafor; median stem cell yield for NDMM pts was 6.2 x 106 (range 2-15 x 106) CD34+ cells/kg. A total of 85 (75 NDMM, 10 RMM) pts received ≥1 dose of maintenance treatment; 63 (56 NDMM, 7 RMM) pts have received all 12 maintenance cycles. In NDMM pts, ORR was 87%, with 64% ≥VGPR and 12% ≥CR, by the end of induction. By the end of maintenance, ORR, ≥VGPR and ≥CR rates were 97%, 82% and 51% in NDMM pts who underwent ASCT and 83%, 70% and 30% in NDMM pts who did not receive ASCT. In RMM pts, ORR, ≥VGPR and ≥CR rates were 79%, 71% and 29% by the end of induction and 86%, 71% and 64% by the end of maintenance. At a median follow up of 24.8 mo in NDMM pts and 26.6 mo in RMM pts, median duration of response was not reached (NR). Median PFS (Figure) was NR in NDMM pts, regardless of transplant status, and was 21.7 mo in RMM pts; median OS was NR in NDMM pts and was 30.1 mo in RMM pts. In NDMM pts the 24-mo PFS rate was 89% in pts who underwent ASCT and 72% in pts who did not receive ASCT. The 24-mo OS rate was 90% for NDMM pts. In RMM pts, the 24-mo PFS and OS rates were 48% and 64%, respectively. All treated pts had ≥1 TEAE. Common TEAEs (≥25%) included fatigue, nausea, cough, diarrhea, upper respiratory tract infection, back pain, vomiting, insomnia, dyspnea, constipation, and headache. Grade 3/4 TEAEs were reported in 62% of pts; the most common (≥10%) was neutropenia (14%). Serious TEAEs occurred in 33% of pts; the most common (>2%) were pneumonia, atrial fibrillation and pulmonary embolism. TEAEs led to permanent treatment discontinuation in 7% of pts, with 2% related to treatment. TEAEs resulted in death in 2 pts (nephrotic syndrome, sudden death); both unrelated to treatment. Infusion reactions (IRs) occurred in 56% of pts including grades 1-2 in 52% of pts, grade 3 in 3% of pts and grade 4 in 1% of pts. Most common (>5%) IRs were chills, cough, dyspnea, nausea, pruritus, flushing and nasal congestion. Conclusion: Maintenance with DARA monotherapy for 12 mo increased the >CR rate in NDMM and RMM pts, consistent with observations in prior studies that longer DARA treatment improves depth of response. Importantly, the increase in ≥CR rate was associated with durable PFS and OS. The 24-mo PFS rates in NDMM and RMM pts compare favorably with results for DARA-VMP and DARA-Vd in NDMM and RRMM, respectively. Safety profile was consistent with previous reports of DARA, with no new safety concerns observed with longer follow-up. These data indicate that DARA-CyBorD is a safe, effective MM treatment and that DARA maintenance increases depth of response and achieves durable remissions. Disclosures Rifkin: Amgen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees. Melear:Texas Oncology: Employment; DARA: Speakers Bureau. Faber:Cardinal Health: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Kite: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Bensinger:Amgen, Celgene: Other: Personal Fees, Research Funding, Speakers Bureau; Takeda, Janssen: Speakers Bureau; Sanofi, Seattle Genetics, Merck, Karyopharm: Other: Grant. Burke:Gilead: Consultancy; Celgene: Consultancy; Roche/Genentech: Consultancy. Narang:Celgene: Speakers Bureau. Stevens:Astellas: Consultancy. Gunawardena:Janssen: Employment, Equity Ownership. Lutska:Janssen: Employment. Qi:Janssen: Employment. Ukropec:Janssen: Employment, Equity Ownership. Qi:Janssen: Employment. Lin:Janssen: Employment, Equity Ownership. Yimer:Amgen: Consultancy; Clovis Oncology: Equity Ownership; Puma Biotechnology: Equity Ownership; Celgene: Honoraria; Seattle Genetics: Honoraria; Janssen: Speakers Bureau; AstraZeneca: Speakers Bureau.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4496-4496 ◽  
Author(s):  
Luke Eastburg ◽  
David A. Russler-Germain ◽  
Ramzi Abboud ◽  
Peter Westervelt ◽  
John F. DiPersio ◽  
...  

The use of post-transplant cyclophosphamide (PTCy) in the context of haploidentical stem cell transplant (haplo-SCT) has led to drastically reduced rates of Graft-vs-Host (GvH) disease through selective depletion of highly allo-reactive donor T-cells. Early trials utilized a reduced-intensity Flu/Cy/TBI preparative regimen and bone marrow grafts; however, relapse rates remained relatively high (Luznik et al. BBMT. 2008). This led to the increased use of myeloablative (MA) regimens for haplo-SCT, which have been associated with decreased relapse rates (Bashey et al. J Clin Oncol. 2013). Most studies have used a MA total body irradiation (TBI) based regimen for haplo-SCT. Preparative regimens using fludarabine and melphalan (FluMel), with or without thiotepa, ATG, and/or low dose TBI have also been reported using bone marrow grafts. Reports on the safety and toxicity of FluMel in the haplo-SCT setting with PTCy and peripheral blood stem cell (PBSC) grafts are lacking. In this two-center retrospective analysis, the safety/toxicity of FluMel as conditioning for haplo-SCT was evaluated. We report increased early mortality and toxicity using standard FluMel conditioning and PBSC grafts for patients undergoing haplo-SCT with PTCy. 38 patients at the University of Rochester Medical Center and the Washington University School of Medicine underwent haplo-SCT with FluMel conditioning and PBSC grafts between 2015-2019. Outcomes were measured by retrospective chart review through July 2019. 34 patients (89.5%) received FluMel(140 mg/m2). Two patients received FluMel(100 mg/m2) and two patients received FluMel(140 mg/m2) + ATG. The median age at time of haplo-SCT was 60 years (range 21-73). 20 patients were transplanted for AML, eight for MDS, two for PMF, two for NHL, and five for other malignancies. The median Hematopoietic Cell Transplantation-specific Comorbidity Index (HCT-CI) score was 4 (≥3 indicates high risk). 11 patients had a history of prior stem cell transplant, and 16 patients had active disease prior to their haplo-SCT. Seven patients had sex mismatch with their stem cell donor. Median donor age was 42 (range 21-71). 20 patient deaths occurred by July 2019 with a median follow up of 244 days for surviving patients. Nine patients died before day +100 (D100, "early mortality"), with a D100 non-relapse mortality (NRM) rate of 24%. Median overall and relapse free survival (OS and RFS, respectively) were 197 days (95% CI 142-not reached) and 180 days (95% CI 141-not reached), respectively, for the entire cohort. The 1 year OS and NRM were 29% and 50%. The incidence of grades 2-4cytokine release syndrome (CRS) was 66%, and 52% of these patients were treated with tocilizumab. CRS was strongly associated with early mortality, with D100 NRM of 36% in patients with grade 2-4 CRS compared to 0% in those with grade 0-1. The incidence of acute kidney injury (AKI) was 64% in patients with grade 2-4 CRS, and 8% in those without (p < 0.001). 28% of patients with AKI required dialysis. Grade 2-4 CRS was seen in 54% of patients in remission prior to haplo-SCT and in 92% of those with active disease (p = 0.02). Of the 9 patients with early mortality, 89% had AKI, 44% needed dialysis, and 100% had grade 2-4 CRS, compared to 31%, 10%, and 55% in those without early mortality (p = 0.002, p = 0.02, p = 0.01). Early mortality was not significantly associated with age, HCT-CI score, second transplant, disease status at transplant, total dose of melphalan, volume overload/diuretic use, or post-transplant infection. In conclusion, we observed a very high rate of NRM with FluMel conditioning and PBSC grafts for haplo-SCT with PTCy. The pattern of toxicity was strongly associated with grade 2-4 CRS, AKI, and need for dialysis. These complications may be mediated by excessive inflammation in the context of allo-reactive donor T-cell over-activation. Consistent with this, multiple groups have shown that FluMel conditioning in haplo-SCT is safe when using bone marrow or T-cell depleted grafts. Based on our institutional experiences, we would discourage the use of FluMel as conditioning for haplo-SCT with PTCy with T-cell replete PBSC grafts. Alternative regimens or variations on melphalan-based regimens, such as fractionated melphalan dosing or inclusion of TBI may improve outcomes but further study and randomized controlled trials are needed. This study is limited in its retrospective design and sample size. Figure Disclosures DiPersio: WUGEN: Equity Ownership, Patents & Royalties, Research Funding; Karyopharm Therapeutics: Consultancy; Magenta Therapeutics: Equity Ownership; Celgene: Consultancy; Cellworks Group, Inc.: Membership on an entity's Board of Directors or advisory committees; NeoImmune Tech: Research Funding; Amphivena Therapeutics: Consultancy, Research Funding; Bioline Rx: Research Funding, Speakers Bureau; Macrogenics: Research Funding, Speakers Bureau; Incyte: Consultancy, Research Funding; RiverVest Venture Partners Arch Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees. Liesveld:Onconova: Other: Data safety monitoring board; Abbvie: Membership on an entity's Board of Directors or advisory committees.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1528-1528
Author(s):  
Sebastian Stasik ◽  
Jan Moritz Middeke ◽  
Michael Kramer ◽  
Christoph Rollig ◽  
Alwin Krämer ◽  
...  

Abstract Purpose: The enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase and key epigenetic regulator involved in transcriptional repression and embryonic development. Loss of EZH2 activity by inactivating mutations is associated with poor prognosis in myeloid malignancies such as MDS. More recently, EZH2 inactivation was shown to induce chemoresistance in acute myeloid leukemia (AML) (Göllner et al., 2017). Data on the frequency and prognostic role of EZH2-mutations in AML are rare and mostly confined to smaller cohorts. To investigate the prevalence and prognostic impact of this alteration in more detail, we analyzed a large cohort of AML patients (n = 1604) for EZH2 mutations. Patients and Methods: All patients analyzed had newly diagnosed AML, were registered in clinical protocols of the Study Alliance Leukemia (SAL) (AML96, AML2003 or AML60+, SORAML) and had available material at diagnosis. Screening for EZH2 mutations and associated alterations was done using Next-Generation Sequencing (NGS) (TruSight Myeloid Sequencing Panel, Illumina) on an Illumina MiSeq-system using bone marrow or peripheral blood. Detection was conducted with a defined cut-off of 5% variant allele frequency (VAF). All samples below the predefined threshold were classified as EZH2 wild type (wt). Patient clinical characteristics and co-mutations were analyzed according to the mutational status. Furthermore, multivariate analysis was used to identify the impact of EZH2 mutations on outcome. Results: EZH2-mutations were found in 63 of 1604 (4%) patients, with a median VAF of 44% (range 6-97%; median coverage 3077x). Mutations were detected within several exons (2-6; 8-12; 14-20) with highest frequencies in exons 17 and 18 (29%). The majority of detected mutations (71% missense and 29% nonsense/frameshift) were single nucleotide variants (SNVs) (87%), followed by small indel mutations. Descriptive statistics of clinical parameters and associated co-mutations revealed significant differences between EZH2-mut and -wt patients. At diagnosis, patients with EZH2 mutations were significantly older (median age 59 yrs) than EZH2-wt patients (median 56 yrs; p=0.044). In addition, significantly fewer EZH2-mut patients (71%) were diagnosed with de novo AML compared to EZH2-wt patients (84%; p=0.036). Accordingly, EZH2-mut patients had a higher rate of secondary acute myeloid leukemia (sAML) (21%), evolving from prior MDS or after prior chemotherapy (tAML) (8%; p=0.036). Also, bone marrow (and blood) blast counts differed between the two groups (EZH2-mut patients had significantly lower BM and PB blast counts; p=0.013). In contrast, no differences were observed for WBC counts, karyotype, ECOG performance status and ELN-2017 risk category compared to EZH2-wt patients. Based on cytogenetics according to the 2017 ELN criteria, 35% of EZH2-mut patients were categorized with favorable risk, 28% had intermediate and 37% adverse risk. No association was seen with -7/7q-. In the group of EZH2-mut AML patients, significantly higher rates of co-mutations were detected in RUNX1 (25%), ASXL1 (22%) and NRAS (25%) compared to EZH2-wt patients (with 10%; 8% and 15%, respectively). Vice versa, concomitant mutations in NPM1 were (non-significantly) more common in EZH2-wt patients (33%) vs EZH2-mut patients (21%). For other frequently mutated genes in AML there was no major difference between EZH2-mut and -wt patients, e.g. FLT3ITD (13%), FLT3TKD (10%) and CEBPA (24%), as well as genes encoding epigenetic modifiers, namely, DNMT3A (21%), IDH1/2 (11/14%), and TET2 (21%). The correlation of EZH2 mutational status with clinical outcomes showed no effect of EZH2 mutations on the rate of complete remission (CR), relapse free survival (RFS) and overall survival (OS) (with a median OS of 18.4 and 17.1 months for EZH2-mut and -wt patients, respectively) in the univariate analyses. Likewise, the multivariate analysis with clinical variable such as age, cytogenetics and WBC using Cox proportional hazard regression, revealed that EZH2 mutations were not an independent risk factor for OS or RFS. Conclusion EZH mutations are recurrent alterations in patients with AML. The association with certain clinical factors and typical mutations such as RUNX1 and ASXL1 points to the fact that these mutations are associated with secondary AML. Our data do not indicate that EZH2 mutations represent an independent prognostic factor. Disclosures Middeke: Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees. Rollig:Bayer: Research Funding; Janssen: Research Funding. Scholl:Jazz Pharma: Membership on an entity's Board of Directors or advisory committees; Abbivie: Other: Travel support; Alexion: Other: Travel support; MDS: Other: Travel support; Novartis: Other: Travel support; Deutsche Krebshilfe: Research Funding; Carreras Foundation: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees. Hochhaus:Pfizer: Research Funding; Incyte: Research Funding; Novartis: Research Funding; Bristol-Myers Squibb: Research Funding; Takeda: Research Funding. Brümmendorf:Janssen: Consultancy; Takeda: Consultancy; Novartis: Consultancy, Research Funding; Merck: Consultancy; Pfizer: Consultancy, Research Funding. Burchert:AOP Orphan: Honoraria, Research Funding; Bayer: Research Funding; Pfizer: Honoraria; Bristol Myers Squibb: Honoraria, Research Funding; Novartis: Research Funding. Krause:Novartis: Research Funding. Hänel:Amgen: Honoraria; Roche: Honoraria; Takeda: Honoraria; Novartis: Honoraria. Platzbecker:Celgene: Research Funding. Mayer:Eisai: Research Funding; Novartis: Research Funding; Roche: Research Funding; Johnson & Johnson: Research Funding; Affimed: Research Funding. Serve:Bayer: Research Funding. Ehninger:Cellex Gesellschaft fuer Zellgewinnung mbH: Employment, Equity Ownership; Bayer: Research Funding; GEMoaB Monoclonals GmbH: Employment, Equity Ownership. Thiede:AgenDix: Other: Ownership; Novartis: Honoraria, Research Funding.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3229-3229 ◽  
Author(s):  
Ivana N Micallef ◽  
Eric Jacobsen ◽  
Paul Shaughnessy ◽  
Sachin Marulkar ◽  
Purvi Mody ◽  
...  

Abstract Abstract 3229 Poster Board III-166 Introduction Low platelet count prior to mobilization is a significant predictive factor for mobilization failure in patients with non-Hodgkin's lymphoma (NHL) or Hodgkin's disease (HD) undergoing autologous hematopoietic stem cell (HSC) transplantation (auto-HSCT; Hosing C, et al, Am J Hematol. 2009). The purpose of this study is to assess the efficacy of HSC mobilization with plerixafor plus G-CSF in patients with concomitant thrombocytopenia undergoing auto-HSCT. Methods Patients who had failed successful HSC collection with any mobilization regimen were remobilized with plerixafor plus G-CSF as part of a compassionate use program (CUP). Mobilization failure was defined as the inability to collect 2 ×106 CD34+ cells/kg or inability to achieve a peripheral blood count of ≥10 CD34+ cells/μl without having undergone apheresis. As part of the CUP, G-CSF (10μg/kg) was administered subcutaneously (SC) every morning for 4 days. Plerixafor (0.24 mg/kg SC) was administered in the evening on Day 4, approximately 11 hours prior to the initiation of apheresis the following day. On Day 5, G-CSF was administered and apheresis was initiated. Plerixafor, G-CSF and apheresis were repeated daily until patients collected the minimum of 2 × 106 CD34+ cells/kg for auto-HSCT. Patients in the CUP with available data on pre-mobilization platelet counts were included in this analysis. While patients with a platelet count <85 × 109/L were excluded from the CUP, some patients received waivers and were included in this analysis. Efficacy of remobilization with plerixafor + G-CSF was evaluated in patients with platelet counts ≤ 100 × 109/L or ≤ 150 × 109/L. Results Of the 833 patients in the plerixafor CUP database, pre-mobilization platelet counts were available for 219 patients (NHL=115, MM=66, HD=20 and other=18.). Of these, 92 patients (NHL=49, MM=25, HD=8 and other=10) had pre-mobilization platelet counts ≤ 150 × 109/L; the median platelet count was 115 × 109/L (range, 50-150). The median age was 60 years (range 20-76) and 60.4% of the patients were male. Fifty-nine patients (64.1%) collected ≥2 × 109 CD34+ cells/kg and 13 patients (14.1%) achieved ≥5 × 106 CD34+ cells/kg. The median CD34+ cell yield was 2.56 × 106 CD34+ cells/kg. The proportion of patients proceeding to transplant was 68.5%. The median time to neutrophil and platelet engraftment was 12 days and 22 days, respectively. Similar results were obtained when efficacy of plerixafor + G-CSF was evaluated in 29 patients with platelet counts ≤ 100 × 109/L (NHL=12, MM=10, HD=3 and other=4). The median platelet count in these patients was 83 × 109/L (range, 50-100). The median age was 59 years (range 23-73) and 60.4% of the patients were male. The minimal and optimal cell dose was achieved in 19(65.5%) and 3(10.3%) patients, respectively. The median CD34+ cell yield was 2.92 × 106 CD34+ cells/kg. The proportion of patients proceeding to transplant was 62.1%. The median time to neutrophil and platelet engraftment was 12 days and 23 days, respectively. Conclusions For patients mobilized with G-CSF alone or chemotherapy ±G-CSF, a low platelet count prior to mobilization is a significant predictor of mobilization failure. These data demonstrate that in patients with thrombocytopenia who have failed prior mobilization attempts, remobilization with plerixafor plus G-CSF allows ∼65% of the patients to collect the minimal cell dose to proceed to transplantation. Thus, in patients predicted or proven to be poor mobilizers, addition of plerixafor may increase stem cell yields. Future studies should investigate the efficacy of plerixafor + G-CSF in front line mobilization in patients with low platelet counts prior to mobilization. Disclosures Micallef: Genzyme Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding. Jacobsen:Genzyme Corporation: Research Funding. Shaughnessy:Genzyme Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Marulkar:Genzyme Corporation: Employment, Equity Ownership. Mody:Genzyme Corporation: Employment, Equity Ownership. van Rhee:Genzyme Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3279-3279 ◽  
Author(s):  
Ann Janssens ◽  
Michael D. Tarantino ◽  
Robert Bird ◽  
Maria Gabriella Mazzucconi ◽  
Ralph Vincent V. Boccia ◽  
...  

Abstract Abstract 3279 Background: ITP is an autoimmune disorder characterized by increased platelet destruction and suboptimal platelet production. Romiplostim stimulates platelet production via the TPO-receptor, and is recommended for second- and third-line treatment of chronic ITP in adults. We report final data from a large prospective study of romiplostim in adults with ITP of varying duration and severity. Methods: Eligibility criteria were broad: patients ≥18 years of age, who had received prior ITP therapies (final protocol amendment: ≥1, previous amendments: ≥3), with low platelet counts (final amendment: ≤ 30 × 109/L, previous amendments: ≤ 10, ≤ 20 × 109/L) or experiencing uncontrolled bleeding. The only excluded comorbidities were: hematological malignancy, myeloproliferative neoplasms, MDS and bone marrow stem cell disorder. Romiplostim was initiated at 1 (final amendment) or 3 (previous amendments) μg/kg/week, with dose adjustments allowed to maintain platelet counts ≥50 × 109/L. Patients could continue on study until they had access to commercially available romiplostim. Rescue medications were allowed at any time; concurrent ITP therapies could be reduced when platelet counts were > 50 × 109/L. Primary endpoint was incidence of adverse events (AEs) and antibody formation. Secondary endpoint was platelet response, defined as either (1) doubling of baseline count and ≥ 50 × 109/L or (2) ≥20 × 109/L increase from baseline. Results: A total of 407 patients received romiplostim, 60% of whom were female. Median (Q1, Q3) time since ITP diagnosis was 4.25 (1.20, 11.40) years (maximum 57.1 years), with 51% of patients splenectomised and 39% receiving baseline concurrent ITP therapies. Seventy-one percent of patients completed the study, with requirement for alternative therapy and withdrawn consent the most common reasons for discontinuation (5% each). Median (Q1, Q3) on-study treatment duration was 44.29 (20.43, 65.86) weeks (maximum 201 weeks), with a total of 20,201 subject-weeks on study. Incidence and type of AEs were consistent with previous studies. The most common serious treatment-related AEs were cerebrovascular accident, headache, bone marrow reticulin fibrosis (with no evidence of positive trichrome staining for collagen and no evidence suggesting primary idiopathic myelofibrosis), nausea, deep vein thrombosis, hemorrhage and pulmonary embolism, with each reported in 2 of 407 (0.5%) patients. All other serious treatment-related AEs were each reported in one patient. Eighteen patients died; 3 deaths (hemolysis, intestinal ischaema, aplastic anemia) were considered treatment-related. No neutralizing antibodies to romiplostim or TPO were reported. Approximately 90% of patients achieved each of the platelet response definitions, regardless of splenectomy status. Overall, median (Q1, Q3) time to response was 2 (1, 4) weeks for response definition 1, and 1 (1, 3) week for response definition 2. Median (Q1, Q3) baseline platelet count was 14 (8, 21) × 109/L. After 1 week of treatment median (Q1, Q3) platelet count had increased to 42 (18, 101) × 109/L. From week 8 onwards, and excluding counts within 8 weeks of rescue medication use, median platelet counts were consistently above 100 × 109/L (range 101.0–269.5 × 109/L). Median (Q1, Q3) average weekly romiplostim dose was 3.62 (1.99, 6.08) μg/kg. Summary/conclusions: This is the largest prospective study in adult ITP reported to date. The data reported here are similar to those reported for previous romiplostim studies, with romiplostim able to safely induce a rapid platelet response in adult ITP patients with low platelet counts or bleeding symptoms. Romiplostim is an important, well-tolerated, treatment option for adult ITP patients, which significantly increases and maintains platelet counts. Adverse Event Subject Incidence Platelet Response Disclosures: Janssens: Amgen: Consultancy; Roche: Speakers Bureau; GSK: Membership on an entity's Board of Directors or advisory committees. Tarantino:Cangene corporation: Research Funding; Baxter: Research Funding; Talecris: Honoraria, Speakers Bureau; Up-to-date: Patents & Royalties; The Bleeding and Clotting Disorders Institute: Board Member. Bird:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; GSK: Membership on an entity's Board of Directors or advisory committees. Boccia:Amgen: Equity Ownership, Honoraria, Speakers Bureau. Lopez-Fernandez:Amgen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Kozak:Amgen: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Steurer:Amgen: Honoraria. Dillingham:Amgen Limited: Employment, Equity Ownership. Lizambri:Amgen: Employment, Equity Ownership.


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