Dose-reduced Conditioning Research Articles

Comparable outcomes for TBI-based versus treosulfan based conditioning prior to allogeneic hematopoietic stem cell transplantation in AML and MDS patients

Allogeneic hematopoietic stem cell transplantation (allo-HCT) is a standard treatment for patients with AML and MDS. The combination of fractionated total body irradiation(8GyTBI/Flu) with fludarabine is an established conditioning regimen, but fludarabine/treosulfan(Flu/Treo) constitutes an alternative in older/comorbid patients. We conducted a retrospective analysis of 215 AML(in CR) and 96 MDS patients undergoing their first allo-HCT between 2011 and 2022, identifying 53 matched Flu/Treo and 8GyTBI/Flu patients through propensity score matching. Median follow-up of survivors was 3.3 years and 4.1 years. For the Flu/Treo group, 1-year non-relapse mortality (2% vs. 10%, p = 0.03) was lower, while 1-year relapse incidence (16% vs. 13%, p = 0.81) was similar. Three-year outcomes, including relapse-free survival and graft-versus-host disease incidence, were comparable (OS: 81% vs. 74%, p = 0.70; RFS: 78% vs. 66%, p = 0.28; chronic GvHD: 34% vs. 36%, p = 0.97; acute GvHD (100 days): 11% vs. 23%, p = 0.11). Multivariable analysis, considering age, ECOG, HCT-CI, and MRD status, revealed no associations with main outcomes. Dose-reduced conditioning with Flu/Treo or 8GyTBI/Flu demonstrated favorable and comparable survival rates exceeding 70% at 3 years with 1-year NRM rates below 10% and low relapse rates in the matched cohort. These data underline the need for further evaluation of TBI and Treo-based conditionings in prospective trials.

Comparable Survival for Fludarabine and Treosulfan Vs. Fludarabine and TBI As Conditioning Regimens in Patients with AML and MDS Undergoing Allogeneic Stem Cell Transplantation

Introduction Allogeneic stem cell transplantation (alloSCT) is a standard treatment option for patients (pts) with acute myeloid leukemia (AML) and myelodysplastic neoplasia (MDS) with relapse remaining the main cause of treatment failure. For AML pts transplanted in complete remission (CR) or MDS pts, the combination of fludarabin with fractionated total body irradiation (8 GyTBI, “FluTBI”) is an established conditioning regimen. Based on the favorable outcome data reported for fludarabine/treosulfan (“FluTreo”), especially for older and/or comorbid pts, this regimen has become a reliable dose reduced conditioning therapy prior to alloSCT and a valuable alternative to other TBI or chemotherapy-based regimens. Methods We conducted a retrospective analysis of 215 pts with AML in CR and 96 pts with MDS who underwent first alloSCT between 2010 and 2022 with a median follow-up (FU) of survivors of 34 months (range: 1 - 124 months). After conditioning therapy with FluTreo (150mg/m 2 fludarabin, 30g/m 2 treosulfan) or FluTBI (120mg/m 2 fludarabin, 4x2Gy TBI) pts were allografted from matched related (MRD; n=65), 10/10 human leukocyte antigen (HLA)-matched unrelated (MUD; n=200), or 9/10 HLA-matched unrelated donors (MMUD; n=46). For AML pts, any detectable molecular/cytogenetic alteration prior to alloSCT was classified as potentially measurable residual disease. Propensity score matching allowed us to identify 55 pair-matched FluTBI and FluTreo pts (nearest matching for age at alloSCT, sex, disease, HCT-CI score, ECOG, with a caliper distance of 0.5). Results Before matching, pts characteristics differed significantly between FluTreo and FluTBI in terms of age at alloSCT (median 64 vs. 47 yr), underlying disease (AML: 59% vs. 88%), ECOG (≥2 15% vs. 6%) and HCT-CI-Score (≥3 50% vs. 25%). In the AML subgroup, pts with measurable residual disease prior to alloSCT were significantly more frequent in the FluTreo group (68% vs. 48%, p<.001). GvHD prophylaxis consisted of calcineurin inhibitor and methotrexate/MMF in all pts. In addition, pts transplanted from unrelated donors received ATLG (Neovii). In the FluTreo group, more patients were transplanted from MRDs (24% vs. 14%, p.013). After matching, patient characteristics were well balanced with respect to age (median 57 vs. 55 yr, p.11), disease (AML/MDS) ( p .8), HCT-CI score ( p .24), sex ( p .85), donor types (MRD: 25.5% vs. 14.5%, MUD: 58.2% vs. 67.3%, MMUD: 16.4% vs. 18.2%, p .36) and measurable residual disease prior to alloSCT ( p .58). Risk groups for AML and MDS pts at diagnosis were comparable across both groups (ELN for AML and IPSS-R for MDS). Relapse incidences (RI) at 3 yrs were similar for FluTreo and FluTBI pts in the unmatched (25% vs. 25%, p.8) and matched cohorts (28% vs. 28% p .7). The non-relapse mortality (NRM) rate was <10% trending towards a lower NRM rate for the FluTBI group in the unmatched cohorts (at 1 yr: 8% vs. 5%, p .07) and a significant difference after matching (at 1 year 2% vs. 9% p .03). Overall survival (OS) for the whole cohort showed a trend towards an inferior outcome for FluTreo (3 yr: 71% vs. 79% p .06), after matching, no difference could be observed (3 yr: 80% vs. 71% p .54). Leukemia-free survival (LFS) was comparable across conditionings in the unmatched (59% vs. 66% p .42) and the matched cohorts (70% vs. 59% p .42). Irrespective of conditioning therapy, pts with measurable residual disease prior to alloSCT had comparable OS and LFS. However, for the matched cohort, pts with measurable disease treated with FluTreo showed a trend towards an inferior OS and LFS after 3 yr in contrast to FluTBI pts (OS: 66% vs. 80%, p .13; PFS: 58% vs. 67%, p .3). No significant differences could be observed in the incidence of acute onset graft versus host disease (GvHD) grade 2-4 at day 100 after alloSCT. Similarly, occurrence of chronic GvHD at 3 yr did not differ in the matched cohorts (32% vs. 43%, p .4). Conclusion With a meaningful median follow up of 34 months, our data for dose-reduced conditioning with either FluTreo or FluTBI highlight favorable and comparable survival rates of >70%. RI and NRM were low for both regimens. For pts with AML, who received FluTBI, measurable residual disease prior to alloSCT seemed to have no effect on outcome, while for the FluTreo cohort measurable residual disease prior to alloSCT showed a trend towards lower survival rates. This finding should be evaluated in a prospective trial comparing TBI and treosulfan based conditioning.

Follow-up analysis of sex hormone levels and prognosis in women after hematopoietic stem cell transplantation

Objective: To investigate the levels of sex hormone and fertility in female patients after hematopoietic stem cell transplantation (HSCT), as well as their correlation with conditioning regimens, and analyse the effect of hormone replacement therapy (HRT) in young women after HSCT. Methods: Retrospective case series study. The clinical data of 147 women who underwent HSCT in the First Affiliated Hospital of Soochow University from January 2010 to January 2021 were retrospectively analyzed. The sex hormone levels were measured and followed-up, and the survival, menstrual fertility and the use of HRT of the patients were also followed-up. The sex hormone levels were measured after transplantation, and the ovarian function was evaluated. Independent sample t test and χ2 test were used for comparison between the two groups. Results: The median age of the 147 patients was 26 (range, 10-45) years. Of them, 135 patients received allogeneic HSCT and 12 patients received autologous HSCT. Furthermore, 129 patients received myeloablative conditioning, and 18 patients received reduced conditioning dose. The median follow-up time was 50 months (range, 18-134 months). Five patients died of disease recurrence during follow-up. Of the 54 patients with subcutaneous injection of zoladex, three recovered menstruation spontaneously after transplantation, and all of them were myeloablative conditioning patients, one patient gave birth to twins through assisted reproductive technology. Ninety-three patients did not use zoladex before conditioning, two patients with aplastic anemia with non-myeloablative transplantation resumed menstruation spontaneously, and conceived naturally. The level of follicle stimulating hormone after transplantation in patients receiving myeloablative conditioning regimen was significantly higher than that in patients receiving reduced-dose conditioning regimen [(95.28±3.94) U/L vs. (71.85±10.72) U/L, P=0.039]. Among 147 patients, 122 patients developed premature ovarian failure, 83 patients received sex hormone replacement therapy after transplantation, and 76 patients recovered menstruation and improved endocrine function. Conclusions: The incidence of premature ovarian failure is high in female patients after HSCT, and patients have a chance at natural conception. Reducing the dose of conditioning regimen and the application of zoladex before transplantation can reduce ovarian of conditioning drugs. HRT after transplantation can partially improve the endocrine function of patients.

Comparison of Haploidentical Related Donor with Post-Transplant Cyclophosphamide (PTCy) and Umbilical Cord Blood (UCB) Transplantation after Myeloablative Conditioning for Hematological Malignancy

<h3>Background</h3> In recent years, haploidentical related donor (haplo) transplantation has markedly increased, accounting for 17% of allogeneic transplantations in adults compared to 5% with UCB and 18% and 20% respectively, in children with hematological malignancy. As prior studies comparing these two hematopoietic stem cell (HSC) sources were largely limited to patients receiving reduced dose conditioning, the current analyses compared outcomes with these HSC sources after myeloablative conditioning. <h3>Patients</h3> Between 2012 and 2017, there were 375 transplants with haplo HSC (BM, n=126; PB, n=249), and 333 with UCB (188 matched at ≤5/8 HLA alleles and 145 matched at 6-8/8 HLA alleles). All haplo recipients had PTCy, calcineurin inhibitor (CNI) and mycophenylate mofetil (MMF) as GVHD prophylaxis and all UCB recipients were conditioned with TBI 1320 cGy, fludarabine and Cy and received CNI/MMF. The median infused total nucleated dose for ≤5/8 and 6-8/8 UCB transplants were 4.7 and 4.4 × 10⁷/kg, respectively. Recipients of 6-8/8 UCB transplants were younger (14 years vs. 21 and 29 years) and more likely to have lower co-morbidity scores (81% vs. 69% and 63%) compared to recipients of ≤5/8 UCB and haplo transplants. UCB recipients were more likely to have ALL and transplanted in second CR and haploidentical related donor transplants were more likely to have AML and transplanted in first CR. Cytogenetic risk did not differ between HSC groups. <h3>Results</h3> Compared to haplo transplants, relapse was lower in recipients of ≤5/8 UCB and similar to that in recipients of 6/8 UCB. Non-relapse mortality (NRM), however, was higher after UCB regardless of HLA match group (Table 1). While overall survival was higher 1-year after haploidentical transplant (81% vs 68% and 72% after ≤5/8 [p<0.001] and 6-8/8 UCBT [p=0.038], respectively), survival was similar at 2 and 3 years for HSC sources (figure 1). Similarly, leukemia-free survival (LFS) was lower at 1-year (61% vs. 71%, p=0.031) but not at 3-years (55% vs. 54%, p=0.82) after ≤5/8 UCB compared to haplo (Figure 1). LFS was similar after 6-8/8 UCB and haplo at 1-year (64% vs. 71%, p=0.16) and 3-years (52% vs. 54%, p=0.82) (figure 1). <h3>Conclusion</h3> Three-year LFS and overall survival were comparable in recipients of Haplo with PTCy and UCB. While greater HLA mismatch is associated with less relapse after UCB transplant, NRM counters this beneficial effect. Strategies that address the early mortality risk after UCB transplant could further enhance success with this HSC source.

Single Doses of Antibody Drug Conjugates (ADCs) Targeted to CD117 or CD45 Have Potent In Vivo Anti-Leukemia Activity and Survival Benefit in Patient Derived AML Models

Single Doses of Antibody Drug Conjugates (ADCs) Targeted to CD117 or CD45 Have Potent In Vivo Anti-Leukemia Activity and Survival Benefit in Patient Derived AML Models

Single Doses of Antibody Drug Conjugates (ADCs) Targeted to CD117 or CD45 Have Potent In Vivo Anti-Leukemia Activity and Survival Benefit in Patient Derived AML Models

Allogeneic bone marrow transplant (BMT) is a potentially curative approach in patients with refractory or high-risk hematologic malignancies, like acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). Current regimens for patient preparation, or conditioning, prior to BMT limit the use of this procedure due to regimen-related mortality and morbidities. As a result, many eligible patients do not consider transplant and only 2/3 those transplanted are able to tolerate a reduced intensity conditioning regimen, which is associated with increased relapse (Scott, J Clin Onc 2017). Thus, safer and more effective conditioning agents with improved disease control are urgently needed. We developed two novel antibody drug conjugates (ADCs) conjugated to amanitin (AM) targeting CD117 (C-KIT, Pearse 2018), which is expressed on hematopoietic stem, progenitor, AML and MDS cells in >60% of patients (Ludwig, Haematologica 1997). CD45 (Palchaudhuri 2018) is expressed on all lympho-hematopoietic cells and hematologic malignancies except multiple myeloma. We aim to design ADC-based conditioning agents with the dual benefit of specifically depleting primary human hematopoietic stem progenitor cells (HSPCs) to enable BMT while reducing disease burden in leukemia models. ADCs were tested in xenograft murine models inoculated with human AML cells from immortalized cell lines (Kasumi-1, CD117 expressing leukemia; REH-Luc, CD45 expressing AML), and three AML patient-derived xenografts (PDX) expressing both CD117 and CD45 (2 of 3 are from patients that relapsed post allogeneic BMT). In the Kasumi model, a single dose of 0.3 mg/kg anti-CD117-AM on day 7 or 42 after inoculation markedly increased survival (median >240 days) compared to vehicle (median 76 days) or unconjugated anti-CD117 antibody (median 86.5 days) (n=6-8/group, p Anti-CD117-AM and anti-CD45-AM are potent anti-leukemia agents based on these data in humanized murine models with established AML. Together with prior reports on the potency of anti-CD117-AM and anti-CD45-AM as conditioning agents, these non-genotoxic ADCs may be useful in reducing disease burden in patients and in recipients of reduced-dose conditioning who are at high risk of disease relapse.

Single Doses of Antibody Drug Conjugates (ADCs) Targeted to CD117 or CD45 Have Potent In Vivo Anti-Leukemia Activity and Survival Benefit in Patient Derived AML Models

Background. Allogeneic bone marrow transplant (BMT) is a potentially curative approach in patients with refractory or high risk hematologic malignancies, such as acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). Prior to transplant, patients are prepared with non-specific, high dose chemotherapy alone or in combination with total body irradiation, which are associated with early and late morbidities, including organ toxicities, infertility, secondary malignancies, and substantial risk of mortality. As a result, many eligible patients do not consider transplant and of those transplanted, 2/3 can only tolerate reduced intensity conditioning, which is associated with increased relapse rates (Scott et al. Journal of Clinical Oncology 2017, 1154-1161). Thus, safer and more effective conditioning agents with improved disease control are urgently needed. To meet this need, we developed two novel antibody drug conjugates (ADCs) conjugated to amanitin (AM) targeting CD117 (C-KIT, Pearse 2018), which is expressed on hematopoietic stem and progenitor cells and AML and MDS cells in >60% of patients (Ludwig et al. Haematologica 1997, 617-621), and CD45 (Palchaudhuri 2018) which is expressed on all lympho-hematopoietic cells and nearly all hematologic malignancies except multiple myeloma. The aim of the project was to design an agent with the dual benefit of depleting primary human hematopoietic stem progenitor cells (HSPCs) while reducing disease burden in leukemia models.Methods. ADCs were tested in xenograft murine models inoculated with human AML cells from immortalized cell lines (Kasumi-1, a CD117 expressing leukemia cell line, and REH-Luc, a CD45 expressing AML cell line tagged with luciferase), and three patient-derived xenografts (PDX) developed from FLT-3+NPM1+ AML samples (J000106132 [prior treatment with Allogeneic BMT, Sorafenib, Hydroxyurea, and Decitabine], J000106565 [M4/5, prior treatment with Induction chemotherapy, Consolidation HiDAC, Allogeneic BMT], J000106134 [M4, no prior treatment reported]) with varying growth kinetics (median survival of vehicle treated groups was 43, 63, 82 days post inoculation) that express both CD117 and CD45 (Jackson Laboratories).Results. In the Kasumi model, a single injection of 0.3 mg/kg anti-CD117-AM administered on day 7 or 42 after AML inoculation resulted in a marked increase in survival (median >240 days) compared to vehicle treated controls (median 76 days) or unconjugated anti-CD117 antibody (median 86.5 days) (n=6-8 mice/group, p<0.0001). In the REH-Luc model, a single injection of 1 mg/kg anti-CD45-AM on day 5 after AML inoculation resulted in longer survival by a median of 15 days compared to vehicle treated controls or unconjugated anti-CD45 antibody (n=10 mice/group, p<0.0001). For the three PDX, a single intravenous dose of ADCs (anti-CD117-AM, anti-CD45-AM, isotype-AM (ISO-AM), unconjugated anti-CD117 antibody, or vehicle PBS) were administered to AML-PDX animals when 2-5% blasts were observed in the blood. With 4-5 mice/group/AML-PDX model, survival was significantly increased in recipients of 1 mg/kg anti-CD117-AM, and 1 mg/kg anti-CD45-AM as compared to vehicle controls (Figure 1 and Table 1).Conclusions. Anti-CD117-AM and anti-CD45-AM are potent anti-leukemia agents based on these data in humanized murine models with established AML. Together with prior reports on the potency of anti-CD117-AM and anti-CD45-AM as conditioning agents, these non-genotoxic ADCs may be useful to reduce disease burden in patients with active disease and in recipients of reduced dose conditioning who are at high risk of disease relapse. [Display omitted] DisclosuresProctor:Magenta Therapeutics: Employment, Equity Ownership. Hyzy:Magenta Therapeutics: Employment, Equity Ownership. Adams:Magenta Therapeutics: Employment, Equity Ownership. Brooks:Magenta Therapeutics: Employment, Equity Ownership. Gabros:Magenta Therapeutics: Employment, Equity Ownership. McDonough:Magenta Therapeutics: Employment, Equity Ownership. Kien:Magenta Therapeutics: Employment, Equity Ownership. Aslanian:Magenta Therapeutics: Employment, Equity Ownership. Pearse:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Palchaudhuri:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties; Harvard University: Patents & Royalties. Li:Magenta Therapeutics: Employment, Equity Ownership. Kallen:Magenta Therapeutics: Employment, Equity Ownership. Sarma:Magenta Therapeutics: Employment, Equity Ownership. McShea:Magenta Therapeutics: Employment, Equity Ownership. Ladwig:Magenta Therapeutics: Employment, Equity Ownership. Dushime:Magenta Therapeutics: Employment, Equity Ownership. Panwar:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. McDonagh:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Boitano:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Cooke:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties.

Revisiting conditioning dose in newly diagnosed light chain amyloidosis undergoing frontline autologous stem cell transplant: impact on response and survival.

Autologous stem cell transplantation (ASCT) is an important treatment modality in light chain (AL) amyloidosis. Use of reduced-dose melphalan conditioning is common, given the associated organ and functional decline. The impact of full-intensity melphalan conditioning (n=314) was compared to reduced-dose conditioning (n=143). Patients in the full-intensity group were younger, with better performance status, fewer involved organs, lower tumor burden and lower Mayo stage. Full-dose conditioning was associated with higher rate of very good partial response or better (79% vs 62%; P<0.001), complete response rate (53% vs 37%; P=0.003) and organ response rate (74% vs 59%; P=0.002) as compared to reduced-dose conditioning. PFS was superior in the full-intensity group compared to the reduced-dose group (4-year PFS 55% vs 31%; P<0.001) as well as a longer overall survival (OS) 4-year OS (86% vs 54%; P<0.001). In addition, the OS and PFS were significantly lower in the reduced-dose group compared to the full-intensity group in Mayo stage III/IV as well as stage I/II. A multivariate analysis confirmed an independent impact for conditioning dose on PFS/OS. This study calls for re-assessment of the use of reduced-dose conditioning in ASCT for AL amyloidosis.

Newly diagnosed and relapsed follicular lymphoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

Newly diagnosed and relapsed follicular lymphoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

Reduced-Dose Conditioning Comparable to Standard Dose Prior to ASCT in MDS

New data from the RICMAC trial showed similar rates of non-relapse mortality, incidence of relapse, and relapse-free survival in patients with myelodysplastic syndrome or secondary acute myeloid leukemia after conditioning with reduced-dose busulfan plus fludarabine vs standard-dose busulfan plus cyclophosphamide prior to allogeneic stem cell transplantation. Overall survival was higher with the reduced dose, but results were not statistically significant.

Allogeneic stem cell transplantation in patients above 55: suggestion for a further stratification of the HCT-CI.

Allogeneic stem cell transplantation (alloSCT) has become available for elderly patients or for patients with comorbidities by introduction of reduced-intense conditioning. Comorbidity-related prognosis after alloSCT can be estimated by the hematopoietic cell transplantation comorbidity index (HCT-CI). The charts from 85 patients who have undergone 90 alloSCTs between 1999 and 2011 were analysed. Most patients received a dose-reduced conditioning and a graft from an unrelated donor. Patients were stratified for age, HCT-CI, cGvHD versus no cGvHD, and a modified HCT-CI with a further split high-risk score. Age over 60 years did not affect the outcome. Manifestation of cGvHD improved the prognosis significantly. An additional stratification of the high-risk group of the HCT-CI revealed that even a fraction of these patients can have considerable benefit from an alloSCT. Furthermore, this high-risk collective could be clearly discriminated into two groups with different outcomes. The investigation confirms that age is no absolute risk factor for alloSCT and demonstrates the heterogeneity of the high-risk group of the HCT-CI. A comprehensive investigation of an additional stratification is suggested. Furthermore, the authors encourage early withdrawal of immunosuppression, even in elderly patients and patients with comorbidities to permit graft-versus-leukaemia/lymphoma, since cGvHD is associated with a significantly better prognosis.

The Kinetic Of Bone Marrow Fibrosis Regression Predicts Outcome In Myelofibrosis Patients After Allogeneic SCT

IntroductionBone marrow fibrosis is a hallmark of primary or post ET/PV myelofibrosis. Recent studies have shown that allogeneic stem cell transplantation induces rapid bone marrow fibrosis regression suggesting that fibrosis is more a dynamic rather than a static process. So far, no data are reported if fibrosis regression influences outcome after transplantation. Methods and patientsWe studied 94 patients with myelofibrosis who received allogeneic stem cell transplantation at the University Medical Center Hamburg between 2002 and 2010. In 57 patients the complete bone marrow histology prior transplantation and/or on day+30 and +100 after transplantation were available. The median age was 57 years (r: 33–73) and patients were classified as IPSS low-risk (n = 1), intermediate-1 (n = 5), intermediate-2 (n = 18), and high-risk (n = 33). Donor source was unrelated (n = 46) or related (n = 11) and of these 38 were HLA-matched while 19 were HLA-mismatched. 41 had primary and 16 post ET or post PV myelofibrosis. The median number of blasts was 1% (r: 0–17%) and gender was male (n = 32) and female (n = 25). All patients received busulfan-based dose-reduced conditioning regimen. Bone marrow fibrosis was graded according to the European consensus and WHO (MF-0 – 3), respectively, and evaluated by experienced hematopathologists. ResultsBefore transplantation 41 patients (72%) had MF grade 3 and 16 (28%) MF grade 2. After engraftment on day+30 (± 10 days) (n = 48), 3 (6%) had complete regression (MF-0) and 7 (15%) near complete regression of bone marrow fibrosis while 17 (35%) had MF-2 and 21 (44%) had MF-3. On day+100 (± 20 days) complete regression (MF-0) was noted in 11 (25%) and near complete regression (MF-1) in 13 (29%) while 12 (27%) and 8 (18%) had still MF-2 or MF-3, respectively. Patients with complete and near complete regression (MF-0 and MF-1) on day +30 had a 5-year estimated overall survival of 100% and those with MF-2 and MF-3 of 75% (p = 0.09). Patients with complete or near complete regression on day+100 had a 5-year estimated survival of 95% in contrast to 60% for those with MF-2 or MF-3 (p = 0.04).If analyzed by regression by grade at day+100 7 (16%) had a reduction of 3 grades (e.g. MF-3 to MF-0), 12 (27%) of 2 grades, 16 (36%) of 1 grade, and 9 (21%) had no grade reduction at day+100.Reduction of 2 or 3 grades at day+100 resulted in 95% survival at 5 years while reduction of 1 or no grade had a survival of 70% however this difference did not reach statistical significance (p = 0.1). There was no difference of fibrosis regression at day+100 between high risk IPSS and low/intermediate risk patients. Furthermore, in those patients with JAK2V617F mutation and complete or near complete regression 42% still had detectable JAK2V617F mutation level in peripheral blood. In contrast, 81% had complete donor cell chimerism if bone marrow fibrosis was MF-0/MF-1 while only 31% had complete chimerism at day+100 if fibrosis was classified as MF-2 or MF-3. ConclusionThis data on fibrosis regression after allogeneic stem cell transplantation suggests that a more rapid regression - independently of IPSS risk score - resulted in a favorable survival and may be used as an early predictive factor for excellent survival. Disclosures:No relevant conflicts of interest to declare.

Clofarabine/Cyclophosphamide (ClofCy) for Debulking refractory Acute Leukemias Prior to Allogeneic Hematopoietic Stem Cell Transplantation

AbstractAbstract 4504Patients (pts) with acute leukemias i.e. acute myeloid leukemia (AML) and acute lymphocytic leukemia (ALL) suffering form primary refractory disease or refractory relapse have a very poor prognosis. Allogeneic hematopoietic stem cell transplantation (alloHSCT) is the only potential curative treatment option for such pts. However, disease-control prior to HSCT is essential for long term CR. In the present study we have retrospectively analyzed the outcome of pts who received clofarabine (10 mg/m2, d 1–4) and cyclophosphamide (200 mg/m2, d 1–4; ClofCy) to reduce the burden of leukemic cells prior to alloHSCT. A total number of 18 pts (females, n= 11; males, n= 7; median age; 37.5 years, range 21–64 years) with refractory leukaemias (AML, n=14; ALL, n=4) received ClofCy between December 2008 and January 2012 (1 cycle: 7 pts; 2 cycles: 3 pts; 3 cycles: 7 pts; 4 cycles: 1 patient). In all pts a marked decrease in leukemic cells was observed after a median of 2 cycles (range 1–4 cycles). Side effects included infections (n=7), moderate skin rush (n=4), transient increase in ALT and AST (n=2) and diarrhoea (n=1). AlloHSCT was performed in 13/18 pts. Five pts were not eligible for alloHSCT because of severe systemic fungal infections in 3 pts, clinical deterioration in 1 patient, or CNS relapse of leukemia in 1 patient. Myeloablative conditioning (cyclophosphamide/TBI) was administered in 9 pts, and dose-reduced conditioning (FLAMSA n=2; Fludarabin/Melphalan/Carmustin/ATG n=2) in 4 pts. Following stem cell infusion (median number of CD34+ cells/kg: 7.22×106) from a related (n=4) or unrelated (n=9) donor all pts showed rapid haematologic engraftment and full donor chimerism (median time to ANC > 0.5 G/l: 16 days; range: 12–25 days; median time to platelet >20G/l without substitution: 17 days; range: 13–32 days). As evidenced by bone marrow biopsy on day +28, all pts achieved CR following alloHSCT. After a median observation time of 262 days (range: 33–1496 days) 7 pts are alive. One patient died because of acute steroid-refractory graft-versus-host disease (day +48) and one from a systemic fungal infection (day +56). Four pts died after following reoccurrence of leukemia. Three pts had a hematologic relapse (days +383, +275, +141, respectively) and 1 patient developed a myelosarcoma on day +934. Of the 7 patients alive 5 are in continuous CR (691, 673, 555, 533 and 170 days post TX), two patients had a relapse and achieved a CR after DLI or a second HSCT, respectively. Together, we demonstrate that cytoreduction with ClofCy is a novel reasonable treatment approach for pts with refractory acute leukemias prior to alloHSCT. The regimen is relatively well-tolerated and resulted in a high response rate. Whether this novel debulking protocol will lead to improved long term outcome in pts with refractory leukemias remains to be determined in forthcoming studies with larger patient samples and longer observation periods. Disclosures:Valent:Phadia: Research Funding. Sperr:Genzyme: Speakers Bureau.

Impact of ASXL1 Mutations On Outcome After Reduced Intensity Allograft in Patients with Myelofibrosis

AbstractAbstract 1740Mutations in the additional sex combs like 1 gene (ASXL1) have been described recently in patients with myelodysplastic and myeloproliferative syndromes. While in MDS ASXL1 is associated with worse prognosis, the role in MPN is not well defined. The aim of this study was to investigate the prognostic impact of ASXL1 mutations in 136 patients with primary myelofibrosis or post ET/PV myelofibrosis who underwent allogeneic stem cell transplantation after reduced intensity conditioning.Out of 136 patients sufficient genomic DNA prior transplantation was available for 103 patients. The median age of 48 female and 55 male patients was 59 years (range, 33–75y). After busulfan (n= 97) or treosulfan (n=6) based dose-reduced conditioning, patients received a stem cell graft from a related (n= 17) or unrelated donor (n=48). ASXL1 was sequenced by Sanger sequencing, and positive patients were confirmed by an independent sequence analysis.Mutations in ASXL1 were found in 27 patients (26%), of whom 24 had frameshift mutations (23%). ASXL1 mutated and non mutated patients were equally distributed between patients with unrelated (19% pos/81% neg) and related (21% pos/79% neg) donors. ASXL1 mutations were found at the same frequency in Lille low risk (15%), intermediate risk (24%) and high risk (20%) patients.After a median follow up of 41 months (range 26–62) the cumulative incidence of non- relapse mortality at 1 year and relapse at 5 years were 26% (95% CI 16–36) and 26% (95% CI 16–36), respectively, and the 5-year OS was 56% (95% CI 44–68).Patients with ASXL1 mutation did not differ significantly to those without mutation in non relapse mortality (35% vs. 22% p=0.4), relapse incidence (24% vs. 27%, p=0.9) and regarding overall survival. Overall survival for ASXL1 mutated and wildtype patients was not significantly different (47% vs. 59%, p= 0.5) in patients with any ASXL1 mutation and in the subgroup of ASXL1 frameshift mutated patients (48% vs. 59%, p= 0.6). The rates of acute grade II-IV GvHD and of chronic GvHD were similar in ASXL1 mutated and wildtype patients (44% vs. 36%, p=0.5 and 52% vs. 46%, p=0.7, respectively). In summary, ASXL1 is one of the most frequently mutated genes in PMF patients. Patients with ASXL1 mutations have a similar outcome after dose reduced allogeneic HSCT as patients with wildtype ASXL1. Disclosures:No relevant conflicts of interest to declare.

Replacement of hematopoietic system by allogeneic stem cell transplantation in myelofibrosis patients induces rapid regression of bone marrow fibrosis

Bone marrow fibrosis is a hallmark of primary and post ET/PV myelofibrosis. To investigated the impact of replacement of the hematopoietic system in myelofibrosis patients by allogeneic stem cell transplantation on bone marrow fibrosis, we studied bone marrow fibrosis on bone marrow samples from 24 patients with myelofibrosis before and after dose-reduced conditioning followed by allogeneic stem cell transplantation from related or unrelated donor. Using the European Consensus on Grading Bone Marrow Fibrosis, before allografting all patients had advanced fibrosis MF-2 (n = 13) or MF-3 (n = 11). After transplantation, a complete (MF-0) or nearly complete (MF-1) regression of bone marrow fibrosis was seen in 59 % at day +100, in 90 % at day +180, and in 100 % at day +360. No correlation between occurrence of acute graft-versus-host disease, and fibrosis regression on day +180 was seen. We conclude that dose-reduced conditioning, followed by allogeneic stem cell transplantation, resulted in a rapid resolution of bone-marrow fibrosis suggesting the bone marrow fibrogenesis is a highly dynamic rather than static process in patients with myelofibrosis.

Phase II Study of Azacitidine (Vidaza®, Aza) and Donor Lymphocyte Infusions (DLI) As First Salvage Therapy in Patients with Acute Myeloid Leukemia (AML) or Myelodysplastic Syndromes (MDS) Relapsing After Allogeneic Hematopoietic Stem Cell Transplantation (allo-SCT): Final Results From the AZARELA-Trial (NCT-00795548)

Abstract 656 Background:Relapse after allo-SCT is a major cause of treatment failure in patients (pts) with myeloid malignancies and is associated with a poor prognosis. As therapeutic options are limited, treatment of these pts is challenging. Indeed, there is a need for novel strategies which ideally target the leukemic clone and direct the immune system towards an enhanced GvL effect without aggravating GvHD. The hypomethylating agent Aza might provide these properties, and results from retrospective studies investigating Aza+/−DLI in pts with AML/MDS relapsing after allo-SCT were encouraging. Design/Methods:We here report the final results from a prospective single-arm EBMT multicenter phase II trial which aimed to investigate the efficacy and safety of a combination of Aza and DLI as 1st salvage therapy in pts with AML or MDS with hematological relapse after allo-SCT. Treatment schedule contained up to 8 cycles Aza (100 mg/m2/d d1-5, every 28 d) followed by DLI with increasing dosages (1-5×106–1-5×108cells/kg) after every 2ndAza cycle. Results:A total of 30 pts (19 f/11 m, median age 56 years, range 29–71) from 6 German transplant centres were included between January 2009 and May 2010. The majority of pts (n=28, 93%) suffered from AML, while 2 pts (8%) had MDS or MDS/MPN, respectively. At transplant, 16 pts (53%) had active disease (6 induction failure, 7 relapse I/II, 3 untreated) and 14 pts (47%) were in remission (12 CR1, 2 CR2). Following standard-dose (n=4, 13%) or dose-reduced conditioning (n=26, 87%), 10 pts (33%) received a graft from MSD and 20 pts (67%) from MUD. PBSC were used in 29 pts (97%), while 1 pt (3%) received BM. Acute GvHD occurred in 13 pts (46%) and 4 pts (13%) had chronic GvHD prior inclusion. None of the pts had active GvHD at the time of relapse, but 6 pts were still on immunosuppressive therapy. All pts had hematological relapse (median BM blasts: 34%, median chimerism: 67%) at a median time of 160 days (range 19–1699) following allo-SCT. A median of 3 courses Aza (range 1–8) were administered, and 22 of 30 pts (73%) received DLI (median: 1, range: 1–4, median CD3 dose 5×106/kg/DLI, range: 1–100×106). Overall response rate was 47%. Seven pts (23%) achieved CR or CRi, 2 pts (7%) PR, and 5 pts (17%) had stable disease (SD). Median time and median number of Aza cycles to best response were 79 days (range 28–299) and 3 cycles (range 1–8) respectively. Of the 7 pts who achieved a CR, 5 pts continue in CR for a median of 605 days (range 307–763) without any additional treatment, while 1 pt relapsed after 490 days and 1 pt died from GvHD. By July 2011 median follow-up of surviving pts is 645 days (range 564–857) and 5 of 30 pts (17%) are currently alive. Twelve pts have died due to progressive disease (PD), while 7 pts died during (n=3, 2 infection, 1 bleeding) or after the end of therapy (n= 4, 1 GvHD, 2 infection, 1 bleeding). All 5 pts who underwent 2nd allo-SCT died. Median overall survival (OS) of all pts is 117 days (95% CI 66–168 days). Patients with CR/CRi had a significant longer OS than pts not reaching CR/CRi (not reached vs. 83 days, p<.001). Eleven pts (37%) developed aGvHD, while cGvHD was observed in 5 pts (17%). Any type of GvHD was seen in 78% of pts with CR/PR as opposed to 33% in pts with SD/PD (p=.03). Cytopenias grade III/IV occurred in all pts, but were considered to be drug-related in only 11 pts (37%). The most common drug-related grade III/IV non-hematological toxicities were infection and bleeding. Conclusion:Aza and DLI as first salvage therapy is a safe and active approach for pts with AML or MDS who relapse after allo-SCT, and induces durable remissions in a subgroup of pts. Further research to better define target patient groups and combination partners for AZA+DLI is needed. Disclosures:Schroeder:Celgene: Financial travel support. Bug:Celgene: Lecture fees, Membership on an entity's Board of Directors or advisory committees. Luft:Celgene: Research Funding. Kobbe:Celgene: Financial travel support, Research Funding.

Achievement of Sustained Molecular Remission Induces Long-Term Freedom From Disease After Autologous-Allogeneic Tandem Transplantation in Patients with Multiple Myeloma

Abstract 148Multiple Myeloma (MM) is considered to be an incurable disease, but in some patient long-term survival can be achieved after high dose chemotherapy followed by autologous or allogeneic stem cell transplantation. Those patients, who achieved molecular remission, have a high probability of long-term disease-freedom and of cure. More recently the introduction of dose-reduced conditioning and the use of auto-allo tandem approach has broaden the use of allogeneic stem cell transplantation in MM, but the results of prospective trials are controversial. We here investigated within a prospective protocol the incidence and impact of molecular remission on long-term outcome obtained after auto-allo tandem approach in MM. (study registration NCT 00781170).From 4/2000 to 10/2008, 73 patients with a median age of 50 years (r 29–64) and advanced stage II/III MM were included. The conditioning regimen for autologous transplantation consisted of melphalan 200 mg/m2 given divided over 2 days. After an interval of 2–3 months, the patients received a dose-reduced conditioning consisting of melphalan 140 mg/m2, fludarabine 180 mg/m2 and ATG Fresenius® (Fresenius, Bad Homburg, Germany) at a dose of 10 mg/kg for related and 20 mg/kg for unrelated donors on day -3, -2, and -1 followed by allogeneic stem cell transplantation.Remission was defined according to modified EBMT criteria. In 46 patients with CR or nCR minimal residual disease could be monitored by myeloma-specific primers (allele specific oligonucleotides, ASO) targeting IgH gene rearrangements (n=20) or by highly sensitive plasma cell chimerism using real-time PCR after magnet-activated cell sorting of CD138+ cells (n=26). The sensitivity of plasma cell chimerism was 10−4 using real-time PCR and donor/patient specific polymorphisms and 10−5 in case of Y-PCR. Sensitivity for nested PCR with myeloma-specific primers was 10−5. In 5 patients only 1 MRD measurement was available and those patients were excluded from MRD sub-analysis. Molecular complete remission was defined as by least two negative PCR results with ASO primers or achievement of at least two times ≥99.9 % donor chimerism of plasma cells by real-time PCR from bone marrow samples. Sustained MRD negativity was defined by at least 4 negative molecular results either by ASO primer or plasma-cell chimerism. Mixed MRD was defined by negative molecular markers for at least two times, but intermittent positivity was defined by myeloma-specific primers or plasma cell chimerism.Overall 44 patients (60 %) achieved a CR according to EBMT criteria with negative immunofixation. 8 % achieved a VGPR and 18 % a partial remission. 3 % had progressive disease and 11 % were not evaluable for determination of remission. Molecular remission was observed in 30 patients, in 15 patients the molecular markers were sustained negative while in 15 patients molecular markers were only intermittent negative, resulting in an overall complete molecular remission rate of 46 % and a stable sustained complete molecular remission rate of 23 %.After a median follow-up at 7 years the 5 year progressive-free survival was 29 % (95% CI: 17–41%). Patients without del(13q14) had a significantly better PFS than those with del(13q14) (5 y: 56% vs. 17%, p=0.02). Patients who achieved CR after transplantation had improved PFS in comparison to non-CR patients (5 y: 41% vs. 28%, p=0.008). Patients with sustained negative molecular remission had a 5 year PFS of 85 % vs. 31 % for mixed molecular remission (p= 0.003).The 5 year overall survival was 52 % (95% CI: 40–64%). Patients without del(13q14) had significantly improved 5 year survival (75% vs. 40%. p=0.02). Patients who achieved a sustained molecular remission had a 5 year OS of 91 % while those with mixed molecular remission resulted in a 5 year OS of 87 % (p=0.06).The study underlines the importance of the depth of remission and shows that achieving molecular remission as determined by myeloma-specific IgH gene rearrangements and plasma cell chimerism is associated with long-term freedom from disease and potential cure of MM in an auto-/allo SCT approach. [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Haploidentical haematopoietic stem cell transplantation using CD3 or CD3/CD19 depletion and conditioning with fludarabine, cyclophosphamide and antithymocyte globulin for acquired severe aplastic anaemia

Fitzgibbon, J., Iqbal, S., Davies, A., O’Shea, D.,Carlotti, E., Chaplin, T., Matthews, J., Raghavan,M., Norton, A., Lister, T.A. & Young, B.D.(2007) Genome-wide detection of recurring sitesof uniparental disomy in follicular and trans-formed follicular lymphoma. Leukemia, 21,1514–1520.Mao, Z., Quintanilla-Martinez, L., Raffeld, M.,Richter, M., Krugmann, J., Burek, C., Hartmann,E., Rudiger, T., Jaffe, E.S., Muller-Hermelink,H.K., Ott, G., Fend, F. & Rosenwald, A. (2007)IgVH mutational status and clonality analysis ofRichter’s transformation: diffuse large B-celllymphoma and Hodgkin lymphoma in associa-tion with B-cell chronic lymphocytic leukemia(B-CLL) represent 2 different pathways of diseaseevolution. American Journal of Surgical Pathology,31, 1605–1614.Rossi, D. & Gaidano, G. (2009) Richter syndrome:molecular insights and clinical perspectives.Hematologcal Oncology ,27, 1–10.Scandurra, M., Rossi, D., Deambrogi, C., Rancoita,P.M., Chigrinova, E., Mian, M., Cerri, M., Rasi,S., Sozzi, E., Forconi, F., Ponzoni, M., Moreno,S.M., Piris, M.A., Inghirami, G., Zucca, E., Gattei,V., Rinaldi, A., Kwee, I., Gaidano, G. & Bertoni,F. (2010) Genomic profiling of Richter’ssyndrome: recurrent lesions and differences withde novo diffuse large B-cell lymphomas. Hema-tologcal Oncology, 28, 62–67.Smit, L.A., van Maldegem, F., Langerak, A.W., vander Schoot, C.E., de Wit, M.J., Bea, S., Campo,E., Bende, R.J. & van Noesel, C.J. (2006) Anti-gen receptors and somatic hypermutation inB-cell chronic lymphocytic leukemia with Rich-ter’s transformation. Haematologica 91, 903–911.Timar, B., Fulop, Z., Csernus, B., Angster, C., Bog-nar, A., Szepesi, A., Kopper, L. & Matolcsy, A.(2004) Relationship between the mutational sta-tus of VH genes and pathogenesis of diffuse largeB-cell lymphoma in Richter’s syndrome. Leuke-mia, 18, 326–330.

Successful allogeneic peripheral blood stem cell transplantation with reduced intensity conditioning in a patient with severe aplastic anemia and active infection

Infection is the major cause of mortality in patients with severe aplastic anemia (SAA) and often results in postponement of immunotherapy or transplantation treatment. We report on a 23-year-old man with very SAA with almost no neutrophils who was primarily treated with peripheral blood stem cell transplantation from an HLA-identical sibling. He received reduced dose conditioning with cyclophosphamide and antithymocyte globulin during active infection with typhlitis and pneumonia. Cyclophosphamide 50 mg/kg/d was given on Day 4 and Day 3 before transplantation and antithymocyte globulin Fresenius 20 mg/kg/d was given on Day 3 and Day 2. Neutrophils and platelets were engrafted on Day +18 and Day +20 after transplantation. Symptoms and signs of acute or chronic graft versus host disease were not observed as of Day +545 after transplantation. Allogeneic hematopoietic stem cell transplantation with reduced intensity conditioning may be considered as the primary therapy for SAA complicated by severe infection.

Frequency analysis of TRBV subfamily sjTRECs to characterize T-cell reconstitution in acute leukemia patients after allogeneic hematopoietic stem cell transplantation

BackgroundAllogeneic hematopoietic stem cell transplantation (allo-HSCT) leads to a prolonged state of immunodeficiency and requires reconstitution of normal T-cell immunity. Signal joint T-cell receptor excision DNA circles (sjTRECs) are markers of developmental proximity to the thymus that have been used to evaluate thymic function related to T-cell immune reconstitution after HSCT. To assess the proliferative history in different T-cell receptor beta variable region (TRBV) subfamilies of T cells after HSCT, expansion of TRBV subfamily-naive T cells was determined by analysis of a series of TRBV-BD1 sjTRECs.MethodssjTRECs levels were detected by real-time quantitative polymerase chain reaction (PCR) in peripheral blood mononuclear cells (PBMCs) from 43 Chinese acute leukemia patients who underwent allo-HSCT. Twenty-three TRBV-BD1 sjTRECs were amplified by semi-nested PCR. Sixteen age-matched healthy volunteers served as normal controls.ResultssjTRECs levels were low or undetectable in the first 6 weeks after allo-HSCT and increased after 8 weeks post HSCT; however, sjTRECs levels at week 20 post-HSCT were still less than normal controls. Frequencies of TRBV subfamily sjTRECs in PBMCs from recipients at week 8 post-HSCT (29.17 ± 20.97%) or at week 16 post-HSCT (38.33 ± 9.03%) were significantly lower than those in donors (47.92 ± 13.82%) or recipients at pre-HSCT (45.83 ± 14.03%). However, frequencies of TRBV subfamily sjTRECs in recipients at week 30 post-HSCT (42.71 ± 21.62%) were similar to those in donors and recipients at pre-HSCT. sjTRECs levels in donors had a positive linear correlation with sjTRECs levels in recipients within 8-12 weeks post-HSCT. Patients with acute graft-versus-host disease (GVHD) or chronic GVHD had profoundly reduced TRECs levels during the first year post-HSCT. Frequencies of BV22-BD1 sjTRECs and BV23-BD1 sjTRECs in patients with GVHD were significantly lower than those in recipients at pre-HSCT, and the frequencies of BV22-BD1 sjTRECs in patients with GVHD were significantly lower than those in donors.ConclusionsReconstitution of thymic output function resulted in a period of immunodeficiency, with low or undetectable TRECs after transplantation, although fludarabine-based dose-reduced conditioning regimens were used. GVHD could affect reconstitution of thymic output function and reduce sjTRECs levels and frequencies of TRBV-BD1 sjTRECs. Low frequency of BV22-BD1 and BV23-BD1 sjTRECs might be associated with GVHD.