ATG Fresenius Research Articles

ATG Brands and DSA

testing are under development (3,4). Fromthe clinical point of view, ATG treatment has been shownto lead to C4d deposition in the graft, and possibly toantibody-mediated graft damage in rare case reports (5,6).Knowing specificities in advance both makes shifting toanother brand possible and avoids unnecessary overtreat-ment because of a misdiagnosed antibody-mediatedrejection.From the data presented by Popow et al (1), anotherinteresting finding is the higher content of antibodiesagainst CD107a in ATG Fresenius

A Comprehensive and Quantitative Analysis of the Major Specificities in Rabbit Antithymocyte Globulin Preparations

Antithymocyte globulin (ATG) preparations are used for treatment and prevention of graft rejection episodes, graft versus host disease and aplastic anemia. The immunomodulatory and immuosuppressive properties of ATGs are mediated by their interaction with a large variety of antigens expressed on immune and nonimmune cell populations. We have conducted a comprehensive analysis on antibody specificities contained in rabbit ATGs in clinical use, ATG-Fresenius (ATG-F) and Thymoglobulin (THG). We have used retroviral expression cloning to identify novel ATG antigens and demonstrate that together with ATG antigens described earlier, these molecules account for the majority of ATG antibodies directed to human cells. Moreover, we have employed cell lines engineered to express antigens at high levels to quantify the antibodies directed to each ATG antigen. We have used cell lines expressing the T cell receptor complex, CD2 and CD28 to remove antibodies to these antigens from ATG preparations and demonstrate that this treatment abrogated the ability of ATGs to induce activation and forkhead box P3 expression in T cells. Comprehensive information and differences on the antigens targeted by ATG-F and THG as well as novel approaches to assess their functional properties are the basis for a better understanding of their immunomodulatory capacities and might eventually translate into improved ATG-based regimen.

Pharmacokinetics (PK) Study Of Antithymocyte Globulins Fresenius (ATG-F) Prior To Allogeneic Stem Cell Transplantation: Implications For Timing Of Graft and Early Adoptive Immunotherapy Infusions

Background Antithymocyte globulins Fresenius (ATG-F) are purified, concentrated preparations of polyclonal immunoglobulin G from hyperimmune serum of rabbits immunized with human thymus activated lymphocytes. These immunoglobulins induce immunosuppression through T-cell depletion and immune modulation. The polyclonal nature of ATG-F is responsible for its effects on the immune system: T-cell depletion in blood and peripheral lymphoid tissues through complement-dependent lysis and T-cell activation and apoptosis; modulation of molecules involved in leukocyte-endothelium interactions; induction of apoptosis in B-cell lineages; interference with dendritic cells. ATG-F administered before allogeneic hematopoietic stem cell transplantation (allo-HSCT) reduces the risks of graft rejection and graft-versus-host disease (GvHD), but the slow clearance of the xenoserum might delay immune reconstitution, increase the risk of disease relapse and impair the activity of a donor lymphocyte infusion (DLI) performed early after allo-HSCT. Methods We studied 24 patients with hematologic malignancies, who underwent allo-HSCT from familiar or unrelated donors, after a conditioning regimen based on myeloablative treosulfan and fludarabine. As graft rejection and GvHD prophylaxis, 17 patients received ATG Fresenius at the dose of 10 mg/kg over 16 hours at day -4,-3 and -2 before HSCT; 5 patients received in vivo T-cell depletion at the dose of 20 mg/kg at day -4,-3 and -2 before HSCT; 2 more patients received ATG Fresenius at the dose of 10 mg/kg much earlier before allo-HSCT (day -14, -13 and -12) since the treatment protocol included a donor DLI at day +3 after transplantation. We collected serum samples at different timepoints, from the first ATG dose to at least 3 weeks after HSCT. We used a flow cytometry-based assay to detect the concentration of free T-cell specific rabbit IgG (SRIgG) which corresponds to the serum biological activity against human T-lymphocytes, as opposed to the levels of unspecific rabbit IgG (RIgG) by ELISA, which lack anti-T-cell function. Results In our cohorts of patients we observed a concentration peak at 64 hours after the first ATG administration, corresponding to the end of the last immunoglobulin dose administration. Interestingly, patients who received the 20 mg/kg dose of serum reached four times higher levels of SRIgG, suggesting a non-linear correlation between the administered dose and the measured plasmatic peak concentrations. Moreover, the terminal elimination half life of SRIgG is significantly shorter than the one of RIgG: 14 vs 67 days (data not shown), indicating that, for the dose of 10 mg/kg, 10 days after HSCT, SRIgG titre has already reached sub-therapeutic levels. Conclusions Previous results indicated that in vivo specific activity of rabbit ATG Fresenius disappears from circulation around day +7 after their last administration (at the dose of 10 mg/kg, day -4, -3, 2). Based on our current data, we can suggest that residual specific anti-lymphocyte activity is dependent upon i. timing and ii. dosage of ATG administration, although this correlation might not be linear. According to these results, current policies of a fixed schedule for DLI infusion should be revisited and possibly adapted to each patient, based on specific conditioning protocols. Disclosures: Seitz: Fresenius Biotech GmbH: Employment. Martinius:Fresenius Biotech GmbH: Employment.

Clinical Experience With Thymoglobulin and Antithymocyte Globulin-Fresenius as Induction Therapy in Renal Transplant Patients: A Retrospective Study

We describe our experiences with, and compare the outcomes of, 2 groups of renal transplant patients treated with thymoglobulin or antithymocyte globulin-Fresenius as induction therapy at transplant to reduce the incidence of acute rejection and prevent delayed allograft function. Twenty-four recipients of deceased-donor or living-donor kidney transplants received thymoglobulin, and 23 patients received antithymocyte globulin-Fresenius. Patient and graft survival and efficacy and safety were assessed at 3 months. The demographic characteristics of both groups were comparable, but the predominant donor type was significantly different. Incidence of complications, delayed graft function, and creatinine concentrations were comparable in both groups. At 3 months after the transplant, patient survival rate was 92% in the thymoglobulin group and 96% in the antithymocyte globulin-Fresenius group (P > .05), and death-censored graft survival rate for both groups was not significantly different. Average hematocrit and lymphocyte, neutrophil, and platelet counts were comparable in both groups at 3 months' follow-up. Average white blood count at 1 month was significantly different between the groups: at 5.62 ± 2.45 × 103 cells/mm³ in the thymoglobulin group and 7.85 ± 4.10 × 103 cells/mm³ in the ATG-F group (P < .05). Considering the study design limitations, we observed that our group of treated patients, safety, and efficacy of thymoglobulin and antithymocyte globulin-Fresenius were generally comparable.

Randomized Trial On GvHD Prophylaxis with or without Anti T Cell Globulin ATG Fresenius (ATG-F) in Allogeneic Hematopoietic Cell Transplantation From Matched Unrelated Donors: Updated Results and Evaluation of the European Group for Blood and Marrow Transplantation (EBMT) Risk Score.

AbstractAbstract 3090 Background:Previously, in 201 adult patients with allogeneic hematopoietic cell transplantation from matched unrelated donors, we demonstrated that addition of ATG-F to standard cyclosporine, methotrexate GvHD prophylaxis (control) significantly reduces acute and chronic GvHD without negatively affecting non-relapse mortality (NRM), relapse, disease-free survival (DFS) and overall survival (OS) [1,2]. Methods:Now, we present updated results of extended follow-up (median 5.5, Q1 5.0, Q3 6.5 years). Furthermore, we investigated whether the European Group for Blood and Marrow Transplantation (EBMT) risk score (0 to 7 points) based on the sum of points for patient age (20–40y: 1 point, >40y: 2 points), disease stage (intermediate: 1 point, late: 2 points), time interval from diagnosis to transplant (>12m: 1 point), donor type (unrelated: 1 point), and donor-patient sex combination (donor female, patient male: 1 point) [3] was able to predict outcome with respect to OS in our trial. The explained variation R2 of the risk score was calculated by setting the prediction error (Integrated Brier Score) of the score in relation to the prediction error of an overall estimate of OS without dividing the patients into different risk groups. Results:The incidence of extensive chronic GvHD after 5 years was 13.6% in the ATG-F group vs 48.9% in the control group (p<0.0001). The 5-year rates with respect to outcome were: DFS 44.3% vs 37.2% (p=0.67), relapse 35.2% vs 29.9% (p=0.46), relapse mortality 29.7% vs 27.7% (p=0.99), NRM 20.5% vs 32.9% (p=0.15), and OS 49.8% vs 39.1% (p=0.28), ATG-F vs control respectively. Patients’ distribution to the EBMT risk score was 1 point 2, 2 points 43, 3 points 59, 4 points 43, 5 points 32, 6 points19, 7 points 1, unknown 2.Table 1Prognostic effect of the EBMT risk score, 5-year OS rates in the different risk groups in comparison to the respective rates reported for the EBMT patients [3]ATG-F-trialEBMT patients [3]EBMT scorePatients/deathsHazard Ratio 95% CI5-year OS rate 95%-CIEBMT score5-year OS rate 95%-CI1-245/191.000.55 [0.39,0.69]10.63 [0.60,0.67]10.54 [0.51,0.58]359/321.42 [0.80,2.50]0.45 [0.32,0.57]30.44 [0.40,0.48]443/231.51 [0.82,2.78]0.48 [0.32,0.62]40.33 [0.29,0.36]5-752/352.19 [1.25,3.83]0.32 [0.20,0.45]50.24 [0.18,0.31]The trend test for increasing risk with increasing risk score resulted in p=0.006. The risk score is able to separate patients with regard to OS, but in univariate and multivariate analyses of the factors building the score (age, disease stage, time from diagnosis, patient/donor sex) only disease stage showed a significant and relevant effect on OS (hazard ratio: intermediate vs early 1.54 95%-CI [0.92,2.56], late vs early 1.98 [1.30,3.02], trend test p=0.001). Thus, the addition of points to the risk score for factors that do not have a prognostic effect results in a dilution of its prognostic ability. In fact, the explained variation of the factor disease stage alone was higher than that of the risk score (R2=3.8% vs R2=3.4%).The main prognostic factor in our trial besides disease stage was donor age [4]. We therefore analyse the effect of a new risk score based on the sum of points for these two factors: donor age (>40y: 1 point) and disease stage (intermediate: 1 point, late: 2 points).Table 2Prognostic effect of new risk score, and 5-year OS rates.ATG-F-trialNew scorePatients/deathsHazard Ratio 95% CI5-year OS rate 95%-CI061/221.000.62 [0.48,0.73]169/412.12 [1.26,3.57]0.41 [0.29,0.52]245/312.69 [1.56,4.66]0.30 [0.18,0.44]313/113.86 [1.87,7.97]0.15 [0.02,0.39]The trend test for increasing risk with increasing score resulted in p<0.0001, and the explained variation was R2=8.1%. Conclusion:After a long-term follow-up of 5.5 years, it could be confirmed that ATG-F GvHD prophylaxis provides a sustained protective effect without compromising relapse and survival. The EBMT risk score is able to separate patients with regard to OS, but in our trial another risk score based on disease stage and donor age can be defined leading to a better prediction of OS. As this score was derived in the same dataset, the assessment of its predictive ability is overoptimistic and it has to be validated in an independent study. Disclosures:Finke:Fresenius Biotech GmbH: Honoraria, Research Funding. Bethge:Fresenius Biotech GmbH: Lecture remuneration Other. Bertz:Fresenius Biotech GmbH: Lecture remuneration Other.

HLA Haploidentical Stem Cell Transplantation After Removal of αβ+ T Lymphocytes and B Lymphocytes Is an Effective Treatment for Children with Life-Threatening, Non-Malignant Disorders

AbstractAbstract 2018▪▪This icon denotes a clinically relevant abstract Introduction.Although HLA haploidentical hematopoietic stem cell transplantation (HSCT) has been largely employed in children with life-threatening non-malignant disorders, the survival of patients given this type of allograft has been reported to be inferior to that of patients transplanted from a compatible, unrelated volunteer (UV). We have recently developed a novel method of ex vivo T-cell depletion based on the selective elimination of αβ+ T cells through labeling with a biotinylated anti-TCR αβ antibody, followed by incubation with an anti-biotin antibody conjugated to paramagnetic beads (CliniMACS®, Miltenyi Biotec, Germany). We also remove B cells through an anti-CD19 monoclonal antibody, to prevent post-transplant EBV-associated lymphoproliferative disease (PTLD). Here, we report the results on 13 patients given this type of allograft. Patients and Methods.Seven patients were males and 6 females, median age at transplantation being 3 yr and 9 mo (range 0.3–28.7). Four patients had severe combined immune deficiency (SCID), three Fanconi anemia (FA), 2 severe aplastic anemia (SAA) and 1 each immune deficiency with polyendocrinopathy, enteropathy, X-linked (IPEX), congenital amegakaryocytic thrombocytopenia (CAMT), hemophagocytic lymphohistiocytosis (HLH) and thalassemia with autoimmune hemolytic anemia. All patients were transplanted from 1 parent (10 from the mother and 3 from the father), the median number of CD34+ cells, αβ CD3+ cells and B cells infused being 17.8×106/kg, 0.64×105/kg and 5.3×106/kg, respectively. Conditioning regimen consisted of treosulfan and fludarabine (FLU) in 7 children (4 SCID, 1 IPEX, 1 HLH and 1 CAMT), FLU and cyclophosphamide in 5 (3 FA and 2 SAA) and busulphan, FLU and thiotepa in 1 child (thalassemia). No patient received pharmacological prophylaxis for graft-versus-host disease (GVHD) after the allograft. All patients were given anti-thymocyte globulin (ATG Fresenius; 3 mg/kg/day) on days -5 through -3 before allografting and, to prevent PTLD, rituximab (200 mg/m2) on day -1. Results.All patients but 2 engrafted, the median time to reach neutrophil and platelet recovery being 13 days (range 8–19) and 11 days (range 7–40), respectively. The 2 patients (1 each with SAA and thalassemia) who had primary graft failure were successfully re-transplanted, the first one from the same parent and the second one from the other parent. No patient experienced secondary graft failure. Grade I/II skin acute GVHD occurred in 3 patients, while no patient had visceral acute GVHD. Limited skin chronic GVHD occurred in 1 of the 8 patients at risk. Two patients (1 with SAA and 1 with CAMT) died from respiratory failure secondary to cytomegalovirus and adenovirus infection at 60 and 80 days after transplantation. Two more patients had episodes of cytomegalovirus re-activation, which were successfully treated with ganciclovir. No patient had EBV-related PTLD. With a median follow-up of 209 days (range 37–543), 11 out of the 13 (84%) patients are alive and disease-free, the Karnofsky/Lansky score being 100. The median chimerism is 100% (range 85–100). Noteworthy, all patients with primary immune disorders and FA are alive and disease-free. T-cell recovery was initially sustained by gd T cells, while, after 45 days from the allograft, αβ T cells predominated. Conclusions.The infusion of B-cell and αβ+ T-cell-depleted hematopoietic progenitors from a HLA-haploidentical parent is an effective treatment option for children with life-threatening congenital or acquired non-malignant disorders. The engraftment rate was high and incidence of acute GVHD was low. The transplantation-related mortality of 15% observed in this cohort is comparable to that observed using a HLA-matched UV. If confirmed in a larger cohort of patients and with a longer follow-up, these results suggest that this transplant option be offered to any child lacking a HLA-identical sibling. Disclosures:No relevant conflicts of interest to declare.

Results of Immunosuppressive Switch in Polyoma Virus Nephropathy in Immunologically High Risk Kidney Transplant Recipients

Introduction: Polyoma virus nephropathy is one of the most dreadful complications after kidney transplantation and usually results in graft lost and jeopardizes the future possibility of re-transplantation. Here we present the results of five kidney transplant recipients (KTRs) who developed polyoma virus nephropathy (BKVN) within the first six months after living-related kidney transplantation (LRKT) and were switched to a new immunosuppressive regimen consisting of: low dose cyclosporin, low dose everolimus and reduced dose of antimetabolites. Methods: Four KTRs were men and one was a woman with an average age of 46 years. All were immunologically high risk KTRs with an average HLA mismatch of 4 and were transplanted their first grafts from living-related donors. All of them had received ATG (Fresenius S) and methylprednisolone (500 mg/day) as an induction therapy. The maintenance immunosuppressive treatment consisted of tacrolimus, mycophenolate mofetil (2 gm/day) and prednisolone (tapered from 40 mg/day to 5 mg/day within 6 weeks). Tacrolimus trough levels were monitored in all patients. All patients also received valganciclovir (900 mg/day) and TMP-SMX (400 mg/day) for prophylaxis. None of the recipients were diabetic but two of them developed NODAT and were receiving insulin treatment (HbA1C's %7.1 and 6.7). Results: Average time for BKVN after transplantation was 164 days. The initial presentation of the BKVN was an increase in serum creatinine levels (average increment from the baseline = 0.7 mg/dL) and CRP levels (average increment rate % 18). Mild proteinuria (< 500 mg/L) was detected in two patients. Average trough tacrolimus level was 9.8 mg/mL). The patients underwent graft biopsy and the biopsy samples were analyzed by a nephropathologist with light microscopy and immunofluorescent stainings. After receiving the initial pathology results, urine and plasma BKV PCRs were measured. Biopsies revealed BKVN with varying degrees of tubulointerstitial inflammation and all stained for SV40. Average plasma BKV copies were 800.000 copies/mL and urinary BKV copies were 160 million/mL. The average serum creatinine level was 1.8 mg/dL at the time of diagnosis. Tacrolimus was discontinued, MMF dose reduced to 1 gm/day and prednisolone dose was reduced to 5 mg/day immediately after diagnosis. Treatment with ciclosporin-A neoral 75 mg b.id. and everolimus 0.5 mg bid was initiated. Conclusion: Average follow-up period after this immunosupressive switch was 4 months. There was an initial increase in CRP and serum creatinine levels (average increase 0.3 mg/dL) after new regimen. The serum creatinine levels didn't return to baseline value but remained stable for four months for all of the patients. The average serum creatinine levels were 1.96 mg/dL at the end of four months. There was no graft loss and evidence of systemic polyoma virus infection. Although the follow-up period is brief and the number of patients in the study are insufficient, these preliminary findings suggest that low dose ciclosporin A and everolimus combination may prevent graft loss and rejection in immunologically high risk KTRs who develop BKVN in the early course after transplantation.

Sex Matching Plays a Role in Outcome of Kidney Transplant

The effect of sex matching between donors and recipients was studied in 135 kidney transplant operations performed in our center between December 1998 and December 2007. Patients were divided into 4 groups: group 1 (63 patients, male donor-male recipient), group 2 (25 patients, male donor-female recipient), group 3 (37 patients, female donor-male recipient), and group 4 (10 patients, female donor-female recipient). Except for donor age, recipient body mass index and donor-recipient HLA AB-DR matching, recipient, and donor demographics, and the immunosuppression were comparable in all groups. Acute rejection and the need for antithymocyte globulin Fresenius rescue therapy were comparable between the 4 donor-recipient combinations. Excellent 1-year actuarial patient and graft survival, comparable hospital stay, and incidence of delayed graft and slow graft function were comparable between the 4 groups. One death occurred, each, in groups 1 and 2; posttransplant complications being comparable. While 1-year graft survival (death censored and uncensored) were comparable, 1-year graft function (serum creatinine) showed that the worst graft function was seen in group 3 (female-to-male). Significant differences between the 4 patient groups also were seen in pretransplant and posttransplant hemoglobin levels as well as in posttransplant arterial hypertension and high-density lipoprotein cholesterol blood levels. Other metabolic indices were generally comparable between the 4 patient groups. These results revealed that sex mismatching (group 2, male donor to female recipient) had the best 1-year graft function but the same 1-year patient and graft survival.

Prognostic Factors Affecting Outcome after Allogeneic Transplantation for Hematological Malignancies from Unrelated Donors: Results from a Randomized Trial

Several prognostic factors for the outcome after allogeneic hematopoietic stem-cell transplant (HSCT) from matched unrelated donors have been postulated from registry data; however, data from randomized trials are lacking. We present analyses on the effects of patient-related, donor-related, and treatment-related prognostic factors on acute GVHD (aGVHD), chronic GVHD (cGVHD), relapse, nonrelapse mortality (NRM), disease-free survival (DFS), and overall survival (OS) in a randomized, multicenter, open-label, phase III trial comparing standard graft-versus-host-disease (GVHD) prophylaxis with and without pretransplantation ATG-Fresenius (ATG-F) in 201 adult patients receiving myeloablative conditioning before HSCT from HLA-A, HLA-B antigen, HLA-DRB1, HLA-DQB1 allele matched unrelated donors. High-resolution testing (allele) of HLA-A, HLA-B, and HLA-C were obtained after study closure, and the impact of an HLA 10/10 4-digit mismatch on outcome and on the treatment effect of ATG-F versus control investigated. Advanced disease was a negative factor for relapse, DFS, and OS. Donor age ≥40 adversely affected the risk of aGVHD III-IV, extensive cGVHD, and OS. Younger donors are to be preferred in unrelated donor transplantation. Advanced disease patients need special precautions to improve outcome. The degree of mismatch had no major influence on the positive effect of ATG-F on the reduction of aGVHD and cGVHD.

Lenalidomide Maintenance Therapy After Toxicity-Reduced Myeloablative Allograft As Salvage Therapy for Efractory/Relapsed Myeloma Patients

Abstract 3024▪FN2▪This icon denotes a clinically relevant abstractReduced-intensity conditioning (RIC) regimen followed by allogeneic stem cell transplantation (SCT) has become a reasonable treatment option for patients with multiple myeloma who are refractory or have relapse to an autograft. However, in comparison to standard myeloablative conditioning RIC resulted in higher risk of relapse. Maintenance therapy after autologous transplantation has shown to improve survival while after allogeneic SCT data are lacking so far. We here report the results of myeloablative toxicity-reduced allograft consisting of intravenous busulfan (12.2 mg/kg) and cyclophosphamide (120 mg/kg) followed by lenalidomide maintenance in 33 patients with multiple myeloma who relapsed to an autograft. A total of 32 patients had received one (n=16), two (n=15), or even three (n=1) autografts, and 1 patient was refractory to 2 induction therapies and failed to collect autologous stem cells. The median duration of remission after the autograft was 12 months. The primary endpoint of the study was non-relapse mortality at 1 year and secondary objectives were evaluation of response, incidence of acute and chronic graft-versus-host disease as well as progression and overall survival. To prevent graft-versus-host disease antithymocyte globulin (ATG Fresenius®) was given at a median dose of 20 mg/kg on day -3, -2, and -1. Lenalidomide was started earliest at day 120 after transplantation if there were no signs of infection or graft-versus-host disease. The median time between last autograft and allogeneic transplantation was 20 months. 19 patients were treated with fully HLA-matched unrelated donor, 8 patients had a mismatch donor, and 6 patients were transplanted from an HLA-identical sibling.2 patients died of treatment-related complications resulting in a cumulative incidence of non-relapse mortality at 1 year of 6% (95% CI: 0–14%). After transplantation 27% developed grade II graft-versus-host disease, and severe grade III graft-versus-host disease was seen in 6% of the patients. Complete remission was noted in 46% of the patients, partial remission was seen in 48% and stable disease in 3%.The median interval between allogeneic transplant and start of lenalidomide was 168 days. The median starting dose was 5 mg (range 5–15 mg) without dexamethasone for 21 day followed by 1 week rest. 9 patients did not receive lenalidomide maintenance due to ongoing graft-versus-host disease, cytopenia or patient’s wish. The median number of lenalidomide cycles was 6 (range 1–30). During follow-up 13 patients discontinued lenalidomide treatment due to progressive disease (n=6), GvHD (n=3), thrombocytopenia (n=2), or fatigue (n=2). In 10 patients lenalidomide dose could be increased to 10 or 15 mg, respectively. The major toxicities of lenalidomide were acute graft-versus-host disease grade I – III (21%), viral reactivation (12%), thrombocytopenia grade III-IV (12%), neutropenia grade III-IV (6%), peripheral neuropathy grade I-II (12%), or other infectious complications (6%). During follow-up 9 patients experienced relapse resulting in a cumulative incidence of relapse at 3 years of 42% (95% CI: 18–66%). The 3 year estimated probability of progression-free and overall survival was 52 % (95% CI: 28–76%) and 79 % (95% CI: 63–95%), respectively. In the current trial neither the deletion 13q14 nor the use of mismatch donor nor the chemosensitivity prior allogeneic SCT could be identified as risk factor for survival. This study showed that toxicity-reduced myeloablative conditioning regimen is feasible and highly effective in relapsed patients with multiple myeloma resulting in an acceptable treatment-related mortality. Lenalidomide as maintenance therapy is feasible early after transplantation but toxicity especially the induction of graft-versus-host disease should be considered. Disclosures:Kröger:Celgene: Research Funding. Kropff:Janssen-Cilag: Consultancy, Honoraria; Celgene: Consultancy, Honoraria.

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.

Unmanipulated HLA-Haploidentical (2-3 antigen-mismatched) Stem Cell Transplantation Using Myeloablative or Reduced-Intensity Preconditioning Regimen,

Abstract 4117Related haploidentical donors, as cord blood, can be alternative donor sources in stem cell transplantation (SCT). Severe GVHD, however, has interfered the progress of haploidentical SCT (haploSCT). To deal with this strong GVHD, T cell depletion has usually been used in US and European countries. In order to pursue the controllable GVL effect by T cells, we have performed unmanipulated haploSCT using myeloablative or reduced intensity preconditioning regimen accompanied with intensified GVHD prophylaxis, including steroids. In this meeting, we will summarize our experience of haploSCT for more than ten years. From August 1998 to September 2010, we have performed 351 cases of haploSCT (all cases were HLA 2–3 antigen mismatched in GVH direction). Patients’ characteristics are sex: male 186, female 168, age: 16–65 years old (median 39), disease: AML/MDS 149, ALL 81, ML 67, others 54. Eighty-three percent of cases underwent SCT in non-complete remission (non-CR) status. Patients under 45 years old underwent myeloablative preconditioning regimen consisting of FLU/CA/CY/TBI 8Gy (haplo-full, n=100), and patients over 45 years old or with comorbidities or repetitive SCT (including second to fifth SCT) underwent reduced intensity preconditioning regimen consisting of FLU/(CA)/BU/ATG or FLU/(CA)/MEL/ATG (haplo-mini, n=251). High dose Ara-C (CA) was optional to reduce tumor burden. As ATG, ATG (Fresenius) 8mg/kg, or thymoglubulin (genzyme) 2–4mg/kg were integrated into conditioning treatments mainly for reduced-intensity transplantation. GVHD prophylaxis consisted of taclolimus (TAC), methylprednisolone (mPSL) 2mg/kg/day, short term MTX, and mycophenolate mofetil (MMF) 15mg/kg/day in haplo-full, and TAC, and mPSL 1mg/kg/day in haplo-mini, respectively. For elderly patients over 50 years old in haplo-mini, MMF was added. Hematopoietic engraftment in haploSCT was as rapid as that in HLA-identical SCT, except 10 cases of graft rejection. The median time to reach a neutrophil account of >0.5 × 109/l was 10 days for haplo-mini and 13 days for haplo-full. Platelet recovery was achieved in 66 % and 60% of patients undergoing haplo-mini and haplo-full, respectively. The median time to reach a nontransfused platelet count of 3 20 × 109/l was 22 days for haplo-mini and 33 days for haplo-full. Sixty percent of haplo-mini patients and 54 % of haplo-full patients did not develop acute GVHD. Acute GVHD (grade II-IV) was observed in 20% for haplo-mini and 36 % for haplo-full. Overall survival at five years was 30% for haplo-full and 40% for haplo-mini, respectively. If limited to CR cases, overall survival reached over 60% in haplo-mini. There is no difference in survival rate among patients’ diseases. In multivariate analysis on survival using variables, including disease status before transplantation, haplo-full vs haplo-mini, mismatches in GVH direction, mismatches in HVG direction, patients’ age, and the number of transplantation times, the disease status (CR) was found to be only a significantly favorable factor (P= 0.0026). Unmanipulated haploSCT is feasible and effective for refractory diseases. ATG dose used in haplo-mini is critical, and rather low compared with that of European cases reported so far. Although it should be too early to refer long term outcome, unmanipulated haploSCT could be considered as an option to control refractory diseases. Disclosures:No relevant conflicts of interest to declare.

Chronic graft-versus-host disease: long-term results from a randomized trial on graft-versus-host disease prophylaxis with or without anti–T-cell globulin ATG-Fresenius

AbstractPrevious randomized graft-versus-host disease (GVHD)-prophylaxis trials have failed to demonstrate reduced incidence and severity of chronic GVHD (cGVHD). Here we reanalyzed and updated a randomized phase 3 trial comparing standard GVHD prophylaxis with or without pretransplantation ATG-Fresenius (ATG-F) in 201 adult patients receiving myeloablative conditioning before transplantation from unrelated donors. The cumulative incidence of extensive cGVHD after 3 years was 12.2% in the ATG-F group versus 45.0% in the control group (P < .0001). The 3-year cumulative incidence of relapse and of nonrelapse mortality was 32.6% and 19.4% in the ATG-F group and 28.2% and 33.5% in the control group (hazard ratio [HR] = 1.21, P = .47, and HR = 0.68, P = .18), respectively. This nonsignificant reduction in nonrelapse mortality without increased relapse risk led to an overall survival rate after 3 years of 55.2% in the ATG-F group and 43.3% in the control group (HR = 0.84, P = .39, nonsignificant). The HR for receiving immunosuppressive therapy (IST) was 0.31 after ATG-F (P < .0001), and the 3-year probability of survival free of IST was 52.9% and 16.9% in the ATG-F versus control, respectively. The addition of ATG-F to standard cyclosporine, methotrexate GVHD prophylaxis lowers the incidence and severity of cGVHD, and the risk of receiving IST without raising the relapse rate. ATG-F prophylaxis reduces cGVHD morbidity.

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.

Prognostic Factors in Allogeneic Hematopoietic Cell Transplantation From Matched Unrelated Donors: Lessons From Extended Follow Up of a Randomized Trial on GVHD Prophylaxis With or Without Anti T-Cell Globulin ATG-Fresenius (ATG-F)

GvHD is a major problem in allogeneic hematopoietic cell transplantation (HCT) fom unrelated donors (UD). In our prospective randomized multicenter trial we could show the efficacy of additional ATG-F to standard GvHD prophylaxis with cyclosporine A and Mtx in reducing all grades of acute and chronic GvHD without negatively affecting NRM, relapse rate or DFS in 201 adult patients (median age 40 (range 18-60) years) with leukemia or MDS in early (n = 107) and advanced (n = 94) disease transplanted after myeloablative conditioning with marrow (n = 37) or blood (n = 134).

Factors impacting short and long-term kidney graft survival: Modification by single intra-operative ­high-dose induction with ATG-Fresenius

A majority of recipients benefited from the intra-operative single high-dose induction (HDI) with ATG-Fresenius (ATG-F) still leaving a group of recipients who did not profit from this kind of induction. Therefore the aim of this retrospective analysis was 1st to identify the risk factors impacting short and long-term graft survival, and 2nd to assess the efficacy of this type of induction in kidney graft recipients with or without these risk factors. A total of 606 recipients receiving two different immunosuppressive treatment regimens (1st: Triple drug therapy [TDT, n=196] consisting mainly of steroids, azathioprine and cyclosporine; 2nd: TDT + 9 mg/kg ATG-F intra-operatively [HDI, n=410]) were included in this analysis and grouped according to their kidney graft survival time (short GST: ≤1 yr, n=100 and long GST: >5 yrs, n=506). The main risk factors associated with a shortened graft survival were pre-transplant sensitization, re-transplantation, rejections (in particular vascular or mixed ones) and the necessity of a long-term anti-rejection therapy. Adding ATG-F single high dose induction to TDT was more efficient in prolonging kidney graft survival than TDT alone not only in recipients without any risk factors (p<0.005) but also in recipients with at least one risk factor (p<0.021). Only in 4.6% of recipients having two or more risk factors this effect could not be demonstrated. The intra-operative single high-dose induction with ATG-F significantly improves the kidney graft survival in recipients with or without risk factors and can therefore be recommended.

Long-term results of allogeneic hematopoietic stem cell transplantation after reduced-intensity conditioning with busulfan, fludarabine, and antithymocyte globulin

Reduced-intensity conditioning (RIC) is widely used for allogeneic stem cell transplantation (SCT). Here we present our long-term experience with RIC regimen consisting of fludarabine (30 mg/m2/day on days -10 to -5), busulfan (4mg/kg/day on days -6 and -5) and antithymocyte globulin (ATG Fresenius, 10 mg/kg/day on days -4 to -1) (Flu-Bu-ATG) in a cohort of 71 patients with various hematological malignancies including chronic myeloid leukemia (24 patients), acute myeloid leukemia (19 patients), lymphoma (20 patients), multiple myeloma (3 patients), myelodysplastic syndrome (3 patients), and myelofibrosis (2 patients). The median age was 50 years. The overall response rate was 87%, including 83% CR and 4% PR. The incidence of acute and chronic GVHD was 35% and 52% and the cumulative incidence of non-relapse mortality at 1 year and 4 years was 8% and 14%. With the median follow-up of 55.0 months, the 2- and 4-year event-free survival (EFS) was 49.0% and 40.3%, and the overall survival (OS) was 73.2% and 62.6%, respectively. Gender, age at SCT, type of donor, disease status at SCT, previous autologous transplantation, and complete chimerism by day +100 did not significantly influence EFS and OS. In a multivariate analysis, no presence of chronic GVHD (p=0.029, HR: 2.5),and diagnosis other than CML (p=0.018, HR: 4.6), and CD34+ dose < 5x106/kg (p=0.010, HR: 2.8) were significant predictors of poor OS. Flu-Bu-ATG protocol is a RIC regimen that combines effective disease control with low non-relapse mortality and acceptable toxicity profile. reduced-intensity conditioning, fludarabine, busulfan, antithymocyte globulin.

Chronic Graft-Versus-Host Disease: Lessons From a Randomized Trial on GvHD Prophylaxis with or without Anti-T-Cell Globulin ATG-Fresenius (ATG-F) In Allogeneic Hematopoietic Cell Transplantation (HSCT) From Matched Unrelated Donors

AbstractAbstract 212 Background:Chronic GvHD (cGvHD) is the leading late complication after allogeneic HSCT. Most previous randomized studies in GvHD prophylaxis failed to demonstrate reduced incidence and severity of cGvHD, and shorter time to discontinuation of immunosuppressive therapy (IST). Aims:We previously reported that addition of ATG-F to standard cyclosporine, methotrexate GvHD prophylaxis (control group) significantly reduced severe acute and chronic GvHD (Finke et al., Lancet Oncology, 2009). Here we present final data and unpublished results on cGvHD with extended follow-up [median of 3 (25%-quartile 2.5, 75%-quartile 3.9) years] on 201 patients with median age of 40 (range 18–60) years, transplanted between 2003 and 2007, with AML (n=101), MDS (n=10), ALL (n=70), CML (n=17), OMF (n=3) in early (1st CR or MDS-RA, n=107), or advanced status of disease (all other, n=94). Results:With extended follow-up the cumulative incidence (CI) of extensive cGvHD after three years was 12.2% in the ATG-F group versus 45.0% in the control group (p<0.0001) (Figure1) [CI of limited + extensive was 30.0% and 60.0% in the ATG-F versus control, respectively, p<0.0001]. CIs were reduced in all main cGvHD target organs: skin [3-year CI, 5.6% to 27.0%; (hazard ratio (HR) =0.18, p=0.0006)], eyes [3-year CI, 2.2% to 20.7%; HR =0.10, p=0.0025)], mouth [3-year CI, 4.4% to 18.8%; HR =0.24, p=0.013)], lung [3-year CI, 3.3% to 16.3%; HR =0.17 p=0.006)], and liver [3-year CI, 16.7% to 33.8%; HR =0.43, p=0.009]. Chronic GvHD decreased relapse rate resulting in HR of 0.49 (p=0.037), 3-year CI of relapse was 32.6% in the ATG-F and 28.2% in the control group (HR=1.21, p=0.47). Extensive cGvHD increased non-relapse mortality (NRM) rate resulting in a HR of 2.1 (p=0.075), 3-year CI of NRM was 19.4% in the ATG-F and 33.5% in the control group (HR=0.68, p=0.47). The 3-year CI of late bacterial infection (post Day+100) was 26.3% and 39.9% in the ATG-F versus control, respectively (HR=0.65, p=0.12). Cox regression analyses on risk factors for developing extensive cGvHD adjusted for treatment arm and acute GvHD (time dependent) found two factors associated with increased extensive cGvHD risk: donor age more than 40 years (HR= 2.02, p=0.025) and disease type [HRs=3.90, 1.56 and 2.62 for patients with MDS, ALL and CML/OMF as compared to AML, respectively; p=0.04]. Overall survival after three years was 55.2% in the ATG-F and 43.3% in the control group (HR=0.84, p=0.39). The HR for receiving IST was 0.58, p<0.00001, and the HR for stopping IST was 1.37, p=0.006 (ATG-F versus control, respectively). At 3 years, the probability of being alive without IST was 46.9% and 18.1% and that of being alive with IST was 8.4% and 26.1 % in the ATG-F versus control, respectively. Conclusion:The addition of ATG-F to standard cyclosporine, methotrexate GvHD prophylaxis significantly reduces the incidence and severity of cGvHD, and the risk of receiving IST without increasing relapse rate. Although the 3-year CI of NRM (19.4% in the ATG-F and 33.5% in the control group, p=0.18) are still non-significantly different, these data demonstrate that ATG-F prophylaxis decreases cGvHD morbidity and may thus provide a long-term survival advantage. [Display omitted] Disclosures:Bethge:Fresenius Biothech GmbH: Lecture remuneration. Finke:Fresenius Biothech GmbH: Research Funding.

Randomized Trial on GvHD Prophylaxis with or without Anti-T-Cell Globulin ATG-Fresenius (ATG-F) In Allogeneic Hematopoietic Cell Transplantation From Matched Unrelated Donors: Final Results and Analysis of Prognostic Factors

AbstractAbstract 1249Previously, we could demonstrate that addition of ATG-F to standard cyclosporine, methotrexate GvHD prophylaxis (control group) significantly reduces severe acute and chronic GvHD, without negatively affecting non-relapse mortality (NRM), relapse rate (RR), disease-free survival (DFS) or overall survival (OS) (Finke et al., Lancet Oncol, 2009). Here we present final data of extended follow-up with a median of 3 (25%-quartile 2.5, 75%-quartile 3.9) years on 201 patients with median age of 40 (range 18–60) years, transplanted between 2003 and 2007, with AML (n=101), MDS (n=10), ALL (n=70), CML (n=17), OMF (n=3) in early (1st CR or MDS-RA, n=107), or advanced status of disease (all other, n=94). At Day +100, the primary efficacy endpoint - severe acute GvHD (aGvHD grade III-IV) or death was reached in 21.4% of patients in the ATG-F group versus 34.7% in the control group (p=0.098). Incidence of grade III-IV aGvHD was 11.7% in the ATG-F group and 25.5% in the control group (p=0.039). With extended follow-up the incidence of extensive chronic GvHD (cGvHD) after three years was 12.2% in the ATG-F group versus 45.0% in the control group (p<0.0001). DFS after three years was 48.0% in the ATG-F and 38.4% in the control group (p=0.71). Incidence of relapse after three years was 32.6% in the ATG-F and 28.2% in the control group (p=0.47). Incidence of NRM after three years was 19.4% in the ATG-F and 33.5% in the control group (p=0.18). OS after three years was 55.2% in the ATG-F and 43.3% in the control group (p=0.39).The effects of the prognostic factors patient age, donor age, patient/donor sex mismatch, patient/donor CMV status, HLA-C difference, type and status of disease, conditioning regimen, source of stem cells, cyclosporine trough levels during the first 30 days, on occurrence of aGvHD III-IV, extensive cGvHD, DFS, relapse, NRM, and OS were analyzed. Factors showing an effect with p<0.05 in univariate analyses were analyzed in multivariate analyses (both adjusted for treatment). Donor age above 40 years negatively affected the risk for aGvHD III-IV (hazard ratio (HR)=2.6, p=0.009), extensive cGvHD (HR=2.1, p=0.021) and OS (HR=1.7, p=0.016); patient age above 40 years negatively influenced NRM (HR=1.8. p=0.041), whereas advanced disease was a risk factor for aGvHD III-IV (HR=2.1, p=0.018), DFS (HR 1.7, p=0.004), relapse (HR=1.7, p=0.038), and OS (HR=1.9, p=0.002). Conclusion: ATG-F significantly reduces severe acute and chronic GvHD. Younger donors are to be preferred in unrelated donor transplantation. Older and advanced disease patients need special precautions to improve outcome. Disclosures:Finke:Fresenius Biothech GmbH: Research Funding. Bethge:Fresenius Biothech GmbH: Lecture remuneration.

Fludarabine and Treosulfan Conditioning for Allogeneic Stem-Cell Transplantation; a Dose- Intense Regimen with Limited Toxicity.

AbstractAbstract 3473Allogeneic stem cell transplantation (SCT) is a potentially curative approach for patients (pts) with various hematological malignancies. However, standard myeloablative conditioning (MAC) is limited to younger, medically fit pts. Reduced-intensity conditioning (RIC) is feasible in pts not eligible for MAC, allowing engraftment and limiting organ toxicity, however, relapse rates are increased, especially in pts not in remission at the time of SCT. Novel approaches are in need to deliver dose intense conditioning, yet with RIC type toxicity, to these pts. Treosulfan is a bifunctional alkylating agent with cytotoxic and immunosuppressive effects. Prior studies demonstrated the feasibility of a fludarabine-treosulfan (FT) conditioning regimen, suggesting it is effective with limited toxicity. To better define the role of FT, we analyzed outcomes of a relatively large cohort of pts, treated in a single institution. Pts were eligible for FT only if considered not eligible for MAC, due to advanced age, comorbidities or extensive prior therapy (including a prior SCT). FT included fludarabine 30 mg/m2, on days -6 to -2, and treosulfan 10–12 gr/m2 on days -6 to -4. Pts with an unrelated donor or no prior chemotherapy were also given ATG (Fresenius, total dose 15 mg/kg). The study included 105 pts, median age 57 years (range, 20–76). Diagnoses included AML (n=56), MDS (n=33), CML (n=3), lymphoid malignancies (n=12) and myelofibrosis (n=1). The donor was an HLA-matched sibling (n=50) or matched unrelated [MUD, n=55; 10/10 match (n=43), 9/10 (n=7), 8/10 (n=5)]. Disease status was defined as early (n=17), intermediate (n=24) or advanced (n=64) by standard criteria. This was a relatively high-risk pt group as only 24 pts (23%) were in CR (first or later), 30 pts had a comorbidity score ≥3 and 22 pts had a Karnofsky score ≤80 at the time of SCT. Twenty-seven pts had a prior SCT; 13 autologous and 14 allogeneic (12 from a different donor). Ninety-five pts engrafted; 7 died prior to engraftment, 3 had early primary or secondary graft failure (MUD-1, mismatched MUD- 2 pts). The median time to neutrophil and platelet engraftment was 12 (range, 9–23) and 16 (range, 10–66) days, respectively. With a median follow-up of 16 months (range, 1–73), 57 pts are alive and 48 have died. The cumulative incidence of acute GVHD and grade III-IV acute GVHD was 26% and 11%, respectively. The cumulative incidence of chronic GVHD was 53%. In all, 8 pts died of complications of GVHD and 16 from other non-relapse causes, including multi-organ failure (n=4), CNS bleeding (n=2), infections (n=7), graft failure (n=2) and suicide (n=1). The cumulative incidence of non-relapse mortality 3-years after SCT was 25% (95%CI, 18–35). Twenty-four pts died of disease recurrence, cumulative incidence 30% (95%CI, 21–44) at 3 years. Considering that only 26% of the pts were in CR at the time of SCT, this rate seems promising. The median 3-year overall (OS) and progression-free survival were 45% (95%CI, 33–57) and 37% (95%CI, 26–49), respectively. The 2 most important factors predicting for OS in multivariate analysis were advanced disease and a low Karnofsky score at the time of SCT. Hazard ratios were 3.7 (p=0.03) and 4.2 (p=0.001), respectively. The 3-year OS was 71% (95%CI, 45–96), 33% (95%CI, 6–69) and 26% (95%CI, 6–46) for low, intermediate and advanced stage, respectively (p=0.03). Best results were obtained in pts with previously untreated MDS (n=33, including 28 pts with > 10% marrow blasts at SCT) and pts with high-risk AML in first CR (n=14), with 3-year OS rates of 61% (95%CI, 42–80) and 65% (95%CI, 38–93), respectively. Interestingly, a second SCT was not associated with a worse outcome. OS was 43% (42/78 alive), 46% (8/13 alive) and 40% (7/14 alive) in first SCT, a second SCT after a prior autologous SCT or a prior allogeneic SCT, respectively. In conclusion, treosulfan-based conditioning is a promising approach in pts with advanced hematological malignancies, not eligible for standard MAC. Favorable results were observed not only in pts with early stage disease, but also in previously untreated advanced MDS. Second SCT was also feasible with FT with a relatively favorable outcome. The low relapse risk suggests that this regimen can be considered a dose-intensive regimen, with a toxicity profile that resembles RIC regimens. The role of FT should be further defined in larger prospective studies. Disclosures:No relevant conflicts of interest to declare.