scholarly journals Haploidentical BMT Using Fully Myeloablative Conditioning, T Cell Replete Grafts, and Post-Transplant Cyclophosphamide (PT/Cy) Has Limited Toxicity and Promising Efficacy in Pediatric Patients with High Risk Hematologic Malignanices

2013 ◽  
Vol 19 (2) ◽  
pp. S165-S166
Author(s):  
Heather Jill Symons ◽  
Allen Chen ◽  
Christopher Gamper ◽  
David Loeb ◽  
Richard J. Jones ◽  
...  
Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3224-3224 ◽  
Author(s):  
Laura Vann ◽  
Milcah Larks ◽  
Christopher Flowers ◽  
Sagar Lonial ◽  
Jonathan Kaufman ◽  
...  

Abstract Background: Successful reconstitution of cellular immunity following allogeneic HPCT reduces the risk of relapse and confers protection against opportunistic infections. We performed an IRB-approved retrospective analysis of patients who underwent allogeneic HPCT and in whom the content of immune cells were measured in the graft and in post-transplant blood samples. Methods: The study population consisted of 122 patients with hematologic disorders (71 acute leukemia; 14 chronic leukemia; 18 lymphoma, 12 MDS; 3 aplastic anemia; and 4 other) who underwent HPCT with a non-T cell depleted graft from an HLA matched related (73) or unrelated (49) donor. 47 patients had low risk disease (AA, ALL CR1, AML CR1, CML CP1), while 75 had high risk disease (all others). The conditioning regimen was non-myeloablative in 38 (31%), included ATG in 18 (15%), and included TBI in 54 (44%). Peripheral blood was drawn at a median of 101 days post-HPCT and analyzed for T-cell subsets, B-cells, NK cells, and dendritic cells. Subjects were divided into three strata based upon the maximal value for the content of each cell subset in the blood. Univariate and multi-variable stepwise logistic regression analyses were performed to test the association of pre-transplant clinical factors, the cells in the graft, and the numbers of immune cells in the blood post-transplant with overall survival. Results: The estimated three-year survival for all subjects was 53%, with death in 49/122 patients (40%) due to progressive disease (37%), infection (29%), GVHD (20%), and other causes (14%). Univariate factors associated with death included high risk, age, the use of reduced intensity conditioning regimen, the use of TBI, the use of ATG during conditioning and the measurement of lower numbers of total T-cells, CD4+ T-cells, CD8+ T-cells, γδ T-cells, DC1 and DC2 in the peripheral blood during the first 200 days post-transplant. A multi-variable Cox model identified non-myeloablative conditioning (HR 2.2, 95% CI 1.2–3.9), TBI (HR 1.9, 95% CI 1.1–3.3), transplant risk strata (HR 1.9, 95% CI 1.0–3.6), and a blood CD3+ T-cell count of less than 600 cells/mcL (HR 1.8, 95% CI 1.2–2.5) as independent risk factors for post-transplant death. The presence of acute GVHD (all grades) or graft constituents was not significantly associated with survival. Limiting the study population to those subjects who survived at least 100 days showed that blood CD3+ T-cells, non-myeloablative conditioning, the use of TBI remained significantly associated with survival. Conclusions: Higher CD3+ counts in the early post-transplant period predict better survival. Patients who fail to achieve a blood CD3+ T-cell count of >600/mcL in the first 200 days post-transplant may be appropriate subjects for adoptive cellular immunotherapy. Low Risk Patients Low Risk Patients High Risk Patients High Risk Patients


2016 ◽  
Vol 22 (3) ◽  
pp. S366-S367
Author(s):  
Evandro Bezerra ◽  
Roberto Luiz da Silva ◽  
Jayr Schmidt Filho ◽  
Marina Santos ◽  
Marina Nascimento ◽  
...  

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2107-2107
Author(s):  
Christopher R. D'Angelo ◽  
Aric C. Hall ◽  
Kyungmann Kim ◽  
Ryan J. Mattison ◽  
Walter L. Longo ◽  
...  

Abstract Introduction: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only curative therapy for myelodysplastic syndrome (MDS) and high-risk acute myeloid leukemia (AML). Patients with high-risk disease have a markedly increased risk of relapse and death following transplant (Armand et al, Blood, 2014). Those who remain disease-free are at risk of severe morbidity from graft-versus- host-disease (GvHD). These issues highlight the importance of improved allo-HSCT platforms designed to reduce relapse rate without increasing risk of GvHD. Decitabine has minimal non-hematologic toxicity and proven efficacy in myeloid diseases (Blum et al, PNAS, 2010). Use of post-transplant cyclophosphamide has demonstrated improved rates of GvHD following allo-HSCT using haplo-identical donors (Bashey et al, JCO, 2013). No studies have reported on outcomes in patients undergoing decitabine immediately prior to transplantation followed by post-transplant cyclophosphamide (PTCy). We hypothesized that the combination of decitabine induction prior to transplant and PTCy would be safe and result in improved disease control with low rates of GVHD, translating into improved survival in a high-risk transplant cohort. Methods In this single-arm, single institution trial, eligible patients received 10 days of IV decitabine at 20mg/m2 no sooner than 24 days and no later than 17 days prior to conditioning. Myeloablative conditioning included fludarabine (50mg/m2 day-5-2), busulfan (IV 3.2mg/kg/day -5-2), and 4 Gy total body irradiation on day -1. Patients above age 65 received a 25% busulfan dose reduction. Patients received a fully or partially matched related bone marrow graft on day 0. GvHD prophylaxis included 50mg/kg of IV cyclophosphamide on day +3-4. Patients with fully matched donors received only PTCy while those with partially matched donors also received mycophenolate mofetil through day +35 and tacrolimus through day +180. Results We enrolled 20 patients, fifteen patients with AML and 5 with MDS. The cohort had a median age of 64 (29-73) and was predominantly male (14/20, 70%). Eight (40%) patients scored as high risk by the HSCT comorbidity index. Eighteen patients (90%) had a high or very high-risk score by the refined disease risk index. All patients received decitabine and 18/20 (90%) underwent transplantation; 2 patients did not receive a transplant due to infectious complications. The majority of patients received a haplo-identical graft (13/18, 72%), and the remaining 5 received a matched related graft. Outcomes are reported in table 2 and figure 1. There were no engraftment failures. Five patients, 3 MDS and 2 AML, are long-term survivors with median follow-up over 3 years. One patient developed donor derived MDS and required a second transplant. Most transplanted patients (13/18, 72%) survived to day 100 with a median post-transplant survival of 138 days. There were 15 deaths on study with the majority due to underlying disease. Six patients (6/20, 30%) died of infectious complications or did not receive a transplant due to infection. Incidence of grade 3-4 acute GvHD was low among those surviving at least 40 days from transplant (3/17, 17%). There were also low rates of chronic GvHD among the 12 patients alive without ongoing GvHD at day 100 (2/12, 17%). Conclusions Decitabine induction followed by myeloablative conditioning in this high-risk population resulted in a high treatment related mortality of 40%. Still, outcomes fell into an expected range for high-risk myeloid disease in an elderly and comorbid population. Based on expected outcomes for high-risk patients from the literature (Armand et al, Blood, 2014), decitabine did not markedly improve overall survival outcomes, recognizing that no direct comparisons are available in our limited study population. Decitabine may increase the risk of peri-transplant infections by contributing to a cumulative immunologic insult combined with disease-related immunosuppression and transplant-related toxicity, highlighting the importance of strict vigilance for infections within this setting. Diligent monitoring may improve infectious outcomes as shown in the second half of the cohort; only two out of the latter 10 patients on protocol died of treatment related complications. There were no cases of engraftment failure. Rates of acute and chronic GvHD using a PTCy platform were low and support other studies reporting this benefit. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 441-441
Author(s):  
Franco Aversa ◽  
Antonio Tabilio ◽  
Adelmo Terenzi ◽  
Stelvio Ballanti ◽  
Alessandra Carotti ◽  
...  

Abstract Despite advances in chemotherapy for acute leukemia, survival is poor when patients have unfavourable prognostic features at diagnosis, when they do not achieve CR after the first induction cycle and when they are in second or later remission. In these circumstances an allogeneic HSCT is preferred. The chance of finding a matched unrelated donor depends on the HLA diversity and although molecular analysis achieves closer matches it reduces the probability of finding a donor. Furthermore, many patients relapse while waiting for transplant. Transplantation of HSCs from a one-haplotype mismatched family member offers an immediate source of HSCs to almost all leukemia patients who urgently need an allogeneic transplantation because of the high-risk of leukemia relapse and who do not have a matched, either related or unrelated, avaible donor. Over the past decade, our group has shown the two major obstacles to mismatched transplants, that is severe acute GVHD in T-cell-replete transplants and graft rejection in T-cell-depleted transplants, can be overcome by infusing a megadose of extensively T-cell-depleted HSCs after an immuno-myelo-ablative conditioning regimen. Since our first reports (Aversa et al. Blood 1994 and NEJM 1998), the main modifications to our original approach were: a) in October 1995, fludarabine was substituted for cyclophosphamide in our TBI-based conditioning regimen; b) peripheral blood cells were positively selected by using initially the Ceprate device and then, since January 1999, the Clinimacs instrument which ensures a 4.5 log T-cell depletion in a one-step procedure with no E-rosetting; c) in the 138 patients transplanted since January 1999 post-transplant G-CSF administration was stopped so as to improve immune recovery. The patient population included 90 AML and 48 ALL, median age 28 years (range 9–62), 40 (29%) in bad-risk CR I, 43 (31%) in second or later CR and 55 (40%) in relapse at transplant. Primary full-donor engraftment was achieved in 125/134 evaluable patients (93%); 8 patients engrafted after second transplants. Overall engraftment was achieved in 133 patients (96%). Without any post-transplant immunosuppressive prophylaxis, grade II-IV acute GvHD occurred in 7/133 evaluable patients and 5/106 developed chronic GvHD. Cumulative incidence (C.I. 95%) of non-leukemia mortality was 36% (19%–53%) and 40% (19%–66%) for patients who were respectively in CR or in relapse at transplant. 38/51 deaths were infection-related. Disease status was the major risk factor for relapse and EFS. Cumulative incidence of leukemia relapse was 27% (12%–45%) and 60% (30%–80%), p=0.006, for ALL patients in CR and relapse respectively; 17% (8%–29%) and 46% (29%–61%), p=0.0001, for AML in CR and relapse respectively. ALL and AML patients transplanted in relapse have, respectively, a 6% and 13% probability of surviving event-free. For those transplanted in remission, EFS is respectively 38% and 50% for ALL and AML patients in any CR at transplant. These results indicate the mismatched transplant should be offered to high-risk acute leukemia patients without a HLA-identical donor not as a last resort, but as a viable option in the early stages of the disease.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3726-3726
Author(s):  
Esther Bachar-Lustig ◽  
Dalit Tchorsh-Yutsis ◽  
Eran Ophir ◽  
Yael Zlotnikov Klionsky ◽  
Noga Or-Geva ◽  
...  

Abstract Abstract 3726 Induction of specific durable immune tolerance towards transplanted donor cells and tissues, without chronic administration of toxic immunosuppressive drugs, represents a most desirable goal in transplantation medicine. Two major approaches addressing this challenge have shown promise in rodent studies. The first is the use of co-stimulatory blockade to inhibit T cells with anti-donor specificity, and the second uses bone marrow (BM) transplantation to achieve a tolerizing chimeric state in which donor antigens are continuously presented in the host thymus. The exceptional clinical potential of the latter approach has been recently demonstrated in a pilot study of combined renal and bone-marrow transplantation from a single donor. However, the presence of alloreactive T cells in the BM graft imposes a significant risk for GVHD which is unacceptable in patients with non-malignant conditions. While T cell depleted BMT could prevent GVHD, the high rejection rate in the absence of aggressive conditioning treatment, represents a significant obstacle. More than a decade ago a co-stimulatory blockade based on anti CD40L was successfully used to induce chimerism following T depleted BMT. However, anti CD40L was later found to be thrombotic in humans, leading to a search for a safer protocol. In previous studies attempting embryonic pancreas xeno-transplantation (Tchorsh-Yutsis et al. Diabetes 2009), we were able to achieve optimal maintenance of the embryonic graft upon transient treatment with CTLA4-Ig and anti CD48, in conjunction with continuous immune suppression with FTY720. However, durable tolerance was not achieved and rejection ensued upon cessation of immune suppression. Therefore, in the present study we sought to investigate the potential of transient treatment with CTLA4-Ig, anti CD48 and FTY720, the equivalents of which are available for clinical use, combined with transplantation of ‘mega dose' T cell depleted BMT. If successful, such a protocol could achieve the desired durable tolerizing chimeric state. Considering the importance of providing empty niches for successful BM engraftment, we initially determined the minimal myeloablation with busulphan which can induce durable chimerism following infusion of congenic B6-SJL(Ly-5.1) TDBM (25×106) into B6 (Ly-5.2) mice. Testing doses ranging from 10mg/Kg to 100mg/Kg busulphan showed that donor type chimerism above 50% was attained at doses >50mg/Kg (40±26%, 66±7% and 75±2% chimerism at 50, 60 and 100 mg/Kg). Consequently, the sublethal dose of 60mg/Kg was selected for further use in all attempts to induce allogeneic chimerism, in conjunction with transient debulking of host lymphocytes by a single infusion of anti CD4 and anti CD8 depleting antibodies. The well tolerated combined sublethal conditioning presented a formidable barrier for engraftment of allogeneic ‘megadose' T cell depleted BM, and no chimerism was achieved. However, addition of transient post transplant treatment with CTLA4-Ig, anti CD48 and FTY720 (Fig 1A), led in two independent experiments to marked donor type chimerism with a median follow up of 116 days (range: 70 to 163 days) beyond cessation of immune suppression (Fig.1B). Thus, while no chimerism could be detected in mice treated post transplant with FTY720 alone (0/7), transient post transplant immune suppression with CTLA4-Ig, anti CD48 and FTY720 resulted in more than 80% donor type chimerism in 8 of 11 mice. As can be seen in Fig.1C, significant chimerism was attained in both the myeloid and lymphoid lineages. Since agents such as Belatacept (CTLA4-Ig) and Alefacept (blocking the interaction of CD48) are available for clinical use, our results suggest a potentially feasible co-stimulatory blockade approach for the induction of durable hematopoietic chimerism under non myeloablative conditioning, as a platform for cell therapy and organ transplantation. Fig. 1: Non myeloablative conditioning and co-stimulatory blockade for chimerism induction. (A) C3H/Hen recipient mice were conditioned with busulfan (2×30mg/Kg) and T cell debulking (TCD) with 300mg anti CD4 and anti CD8. Post transplant treatment included 200mg CTLA4 Ig, 250mg anti CD48, and 0.1mg FTY720 administered at the indicated time points. (B-C): Long term multilineage chimerism (A) Chimerism level 163 days after cessation of immune suppression. (B) Typical multilineage chimerism in the spleen of a chimeric mouse shown in B. Fig. 1:. Non myeloablative conditioning and co-stimulatory blockade for chimerism induction. (A) C3H/Hen recipient mice were conditioned with busulfan (2×30mg/Kg) and T cell debulking (TCD) with 300mg anti CD4 and anti CD8. Post transplant treatment included 200mg CTLA4 Ig, 250mg anti CD48, and 0.1mg FTY720 administered at the indicated time points. (B-C): Long term multilineage chimerism (A) Chimerism level 163 days after cessation of immune suppression. (B) Typical multilineage chimerism in the spleen of a chimeric mouse shown in B. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4389-4389
Author(s):  
Oscar Gonzalez-Llano ◽  
Elias Eugenio Gonzalez-Lopez ◽  
Ana Carolina Ramirez-Cazares ◽  
Edson Rene Marcos-Ramirez ◽  
Guillermo J. Ruiz-Arguelles ◽  
...  

Abstract Patients with high-risk hematological malignancies have a poor prognosis without a hematopoietic stem cell transplant. An HLA- haploidentical donor is available in 95% of the cases, and post-transplant cyclophosphamide permits the use of T-cell replete grafts in settings were ex-vivo manipulation is not available. The experience with HLA-haploidentical HSCT with PBSC and post-tranplant Cy in the pediatric and adolescent population is limited; we report the following experience. We retrospectively collected data on 25 patients (0 to 21 years old) with hematological malignancies, who underwent ambulatory haploidentical HSCT with post-transplant Cy from November 2011 to November 2014. The different conditioning regimens are described in Table 1. All patients received high-dose Cy(50mg/kg) on days +3 and +4. Cyclosporine A (CYA; 6mg/kg/d per os) and mycophenolate mofetil (MMF; 15mg/kg two times daily per os) were started on day +5. MMF was discontinued on day +35 and tapering of cyclosporin started day +90 in the absence of GVHD. All patients received anti-microbial prophylaxis for bacteria, fungal, herpes infection and Pneumocystis jiroveci according to institutional practices. First chimerism was performed at day +30, and second chimerism at day +100. Primary graft failure was defined when neutrophil counts did not exceed 0.5 x 109/L by day +30. Acute and chronic GVHD were graded according to NIH criteria. Patient, donor and stem-cell harvest characteristics are described in Table 1. All patients had high risk hematological malignancies. There were 5 patients who underwent their first transplant on 1st CR, 4 with ALL with high risk cytogenetics and 1 with AML. All other patients were defined as high risk because they were refractory/relapsed. Twenty-three patients (92%) had neutrophil engraftment after a median 17 (7-24) days. Platelet engraftment was observed in 20 (80%) patients after a median of 14.5 (11-23) days, 3 (12%) patients did not have platelet counts below 20,000/mcL. One patient was catalogued as a primary failure for not achieving neutrophil and platelet engraftment by day +30. One patient died before engraftment at day +10 of septic shock. Four patients (16%) died before day +30. The only patient that did not have a complete chimerism, had a diagnosis of AML and 30% of donor cells by day +30, by day +45 relapse of disease was documented. After a median follow-up of 157 days, 13 patients (52%) remain alive, with an estimated 1-year OS of 52% (95%CI: 30.4 - 65.6%).Nine patients (36%) died of complications (mainly infectious) not related to relapse at a median time of 66 days (10-579 days) from stem cell infusion. Nine patients (36%) relapsed in a median time of 105 days (45-288 days); three of those patients died at days +150, +113 and + 370 from transplant. Estimated 1 year event-free survival is 40.2% (95%CI: 41.3 - 75.8%) (Figures 1 and 2). Patients transplanted on 1st CR had a median follow-up of 664 days with an OS and EFS of 80% (4 patients), which was statistically different from the rest of the population (p=0.03) (Figure 3). Among those who engrafted (n=21), 9 cases (42.9%) had grade 2-4 acute GVHD and 4 cases (19%) of grade 3-4 acute GVHD. Three patients (14.3%) developed chronic GVHD, two had mild skin or liver cGVHD. One patient had severe (NIH stage 3) skin cGVHD, she was alive and with a grade 2 cGVHD until last follow up at day +893. Outpatient procedure, HLA-haploidentical HSCT including PBSC as a stem cell source, and post-transplant T-cell in vivo depletion using high-dose cyclophosphamide is feasible in children and adolescents, with acceptable rates of response and GVHD. Table 1. Patient, donor and harvest characteristics Variable N=25 Age, median(range in years) 10 (1-21) Gender, n(%) Male Female 17 (68%) 8 (32%) Diagnosis, n(%) ALL-B ALL-T AML CML 16 (64%) 2 (8%) 5 (20%) 2 (8%) Time from diagnosis to transplant (months) 17.2 (1.9-153.5) Conditioning regimen, n(%) Cy 1500mg/m2 + Flu 75mg/m2 + Bu 9.6mg/kg (IV) Cy 1050mg/m2 + Flu 75mg/m2 + Bu 12 mg/kg (oral) Cy/VP-16/RT Cy/Flu/Mel 16 (64%) 6 (24%) 2 (8%) 1 (4%) Donor, n(%) Mother Father Sister 20 (80%) 3 (12%) 2 (8%) Donor age, median(range in years) 38 (17-49) Infused CD34+ x 106/kg, median(range) 11 (3.2-20) Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1782-1782 ◽  
Author(s):  
Michael Roost Clausen ◽  
Sirpa Leppa ◽  
Peter de Nully Brown ◽  
Jette Soenderskov Goerloev ◽  
Michael Panny ◽  
...  

Abstract Background: Aggressive non-Hodgkin lymphoma (aNHL) relapsing after high-dose therapy or, in not transplant-eligible patients, after 1st-line chemotherapy represents an unmet clinical need. Therefore, we aimed at evaluating a salvage combination regimen based on pixantrone, an aza-anthracenadione recently approved in Europe for patients with multiply relapsed aNHL. Etoposide and bendamustine were chosen as companion compounds due to available feasibility data in combination with anthracenadions, and a well-documented efficacy in salvage regimens for relapsed aNHL. Rituximab was added, if the relapse tumor biopsy was CD20+. Aim: The aim of the present analysis was to summarize the preliminary clinical experience with the PREBEN/PEBEN regimen gathered, on a compassionate need basis, at different European sites and representing the platform for a currently ongoing Nordic phase 1/2 trial in relapsed aNHL. Methods: The adopted schedule consisted of pixantrone 50 mg/m2 i.v. day 1+8, etoposide 100 mg i.v. day 1, bendamustine 90 mg i.v. day 1 with or without the addition of rituximab 375 mg/m2 i.v. day 1 (PREBEN/PEBEN). If feasible, each cycle was given at 3-weekly intervals for a maximum of 6 cycles. All patients were assessed for chemosensitivity with PET/CT, already after cycle 1 or 2. G-CSF support was applied and administered according to local practice. Results: A total of 30 heavily pre-treated patients (19 males and 11 females, age range 49-81 yrs; mean N of previous regimens: 3, range 1-7) with aNHL were treated according to the PREBEN/PEBEN schedule. Seventeen had diffuse large B-cell (DLBCL), six transformed indolent (tIND), and seven peripheral T-cell lymphoma (PTCL). All patients had intermediate or high risk IPI prior to start of salvage therapy. Eight patients (27%) had a complete metabolic response (CMR) and seven (23%) a partial one (PMR), resulting in an overall response rate (ORR) of 50%. Among the histological subtypes, the patients with DLBCL, PTCL and tIND had an ORR of 53% (CMR 35%), 57% (CMR 14%), and 33% (CMR in one out of two responders), respectively. Most responses were achieved early (prior to course nr. 4). Response durations ranged between 2 and 23+ months. Among the 17 patients with DLBCL, nine were frail, non transplant-eligible with relapsed disease, six had primary refractory lymphoma progressing through anthracycline-containing 1st line and platinum-containing salvage therapies, and two had relapses occurring after a post-transplant remission period. While most of the relapsed patients with DLBCL responded , i.e. seven (five CMR and two PMR) of the nine (78%) frail relapsed patients and one of the two (50%) patients with post-transplant relapses, only one out six (17%) primary refractory patients exhibited some chemosensitivity. Interestingly, four out of seven PTCL patients achieved a PMR or CMR allowing them to undergo non-myeloablative allogeneic transplant with subsequent sustained response durations. The treatment schedule was feasible and most patients received it on an out-patient basis. The most common grade 3-4 toxicity was of hematological type (mainly neutropenia and thrombocytopenia), occurring in 52% of the patients. Grade 3-4 infections were observed at a frequency of 21%. No septic deaths were recorded. A previously anthracycline exposed, heavily pre-treated 60-year old female PTCL patient developed symptomatic congestive heart failure effectively reversed by angiotensin converting enzyme inhibitors with normalization of the myocardial ejection fraction. One previously ibritumomab tiuxetan exposed, heavily pretreated patient with tIND developed acute myeloid leukemia with therapy-related cytogenetic features. Conclusions: The PREBEN/PEBEN salvage regimen was feasible in a heavily pre-treated cohort of elderly patients with high-risk aNHL. In individual patients it elicited substantial and durable responses early in the course of therapy. In some younger patients, it proved useful as bridging strategy to a non-myeloablative allogeneic transplant. A phase 1/2 study in relapsed (non-refractory) aNHL was launched in June 2016 (ClinicalTrial.gov identifier: NCT02678299; EudraCT number: 2015-000758-39) and is currently accruing (N=5 pr. Aug 1st, 2016). Disclosures Clausen: Takeda: Research Funding; Novartis: Other: Travel expences; Abbvie: Other: Travel expences. Leppa:Mundipharma: Research Funding; Roche: Honoraria, Other: Travel expenses, Research Funding; Bayer: Research Funding; Janssen: Research Funding; Takeda: Honoraria, Other: Travel expenses; CTI Life Sciences: Honoraria; Amgen: Research Funding; Merck: Other: Travel expenses. Willenbacher:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; European Commision: Research Funding. d'Amore:Servier: Honoraria, Other: Advisory Boards; CTI LIfe Sciences: Honoraria, Other: Advisory Boards.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3255-3255
Author(s):  
Peter Lang ◽  
Michaela Döring ◽  
Anne-Marie Lang ◽  
Patrick Schlegel ◽  
Christian M. Seitz ◽  
...  

Introduction: There are currently two strategies to prevent Graft-versus-Host Diseases (GvHD) mainly applied in haploidentical transplantation. One is ex-vivo T-cell depletion of TcRa/b T-cells and the other is the T-replete approach, in which the donor T-cells remain in the graft and are tolerized in vivo by post-transplant cyclophosphamide (pCy). The ex-vivo depletion strategy does not require post-transplant immune suppression for GvHD prevention, whereas T-replete transplants require intensive immune suppression. A major obstacle for engraftment is the persistence of patients' T-cells despite intensive and myeloablative condition regimens, thus probably leading to rejection of the graft. We hypothesized that both methods could be combined in a setting of Reduced Conditioning setting (RIC). The ex-vivo T-cell depletion would allow to omit post-transplant immunosuppression and the pCy given at day +3 and +4 could induce in-vivo tolerance of the residual patients' T-cells not eliminated by RIC. Therefore, we applied this strategy in patients who were not eligible based on their poor clinical condition and who were considered to endure only a very reduced conditioning regimen. Results: We report on a cohort of 6 pediatric patients who were not eligible for myeloablative condition regimens due to preexisting organ dysfunctions (lungs, gut or liver) but were in urgent need of an SCT from matched unrelated (n=2) or haploidentical family donors (n=4). Diagnoses were: immune deficiencies (n =4; CARMIL 2, STAT 1, ICF 2, 1 not classified), relapsed metastatic ependymoma, refractory Burkitt´s lymphoma. All patients received a non-myeloablative conditioning regimen (ATG (Thymoglobin) 2mg/kg d-9 to d-7, fludarabine 30mg/m² d-6 to d-2, TBI 4Gy d-1, cyclophosphamide 50mg/kg d+3, d+4; adapted from Aversa, Reisner et al. Blood Adv. 2017). One patient additionally received thiotepa 2x5mg/kg on d-2. The CliniMACS® device was used for TCRab/CD19 depletion of peripheral stem cells; a median number of 14x10E6 CD34+ cells/kg bw with 6.4x10E3/kg bw residual TCRa/b T-cells was infused without any further posttransplant immune suppression. Four patients received a single add back of CD45 RA depleted donor T-cells at d+7. Dosages of 1x10E5/kg, 1x10E6/kg or 5x10E6/kg were administered. Two patients received an additional T-cell depleted stem cell boost after application of pCy Engraftment occurred in 4/6 patients; 2 patients rejected their haploidentical grafts and showed complete autologous reconstitution. Median time to reach ANC>500 was 19 days (range 15-23). Four patients had no signs of GvHD; 1 patient had grade I; the patient who had received the highest dose of CD45RA depleted DLI developed grade III but could be treated successfully. No cGvHD occurred. Immune recovery was rapid. Median numbers of CD3+ T-cells, CD3/CD4+ T-cells, CD19+ B cells and CD56+ NK cells at d30 and d100 were 120/µl, 9/µl, 0/µl, 140/µl and 205/µl, 60/µl, 67/µl and 206/µl, respectively. 3 patients are alive and well with a median follow up of 824 days (43-1100). Last observed donor chimerisms were 95-100%. Causes of death in 3 other patients were: MAS/sepsis (STAT 1 deficiency, d 264) and progression in both patients with malignancies (d282 and d73). The patient with relapsed ependymoma showed a transient tumor regression for 3 months posttransplant whereas the patient with refractory Burkitt´s lymphoma had only a short response for 4 weeks. Conclusions: The combination of TCRa/b depletion and pCy allowed to use a very reduced conditioning regimen which could be administered in pediatric patients even with preexisting significant organ dysfunctions without severe side effects. GvHD could be effectively prevented (except in one patient who received a high number of DLI) together with an acceptable engraftment rate provided by post cy. Thus, this method might offer the possibility to establish a donor-derived hematopoiesis without using pharmacological myeloablation and with minimal toxicity and might be the basis for future strategies to further reduce the conditioning regimen, especially for patients with non-malignant diseases. Disclosures No relevant conflicts of interest to declare.


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