Reconstitution of Lymphocyte Subsets and Outcomes After Matched and Mismatched Hematopoietic Stem-Cell Transplantation

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4485-4485
Author(s):  
Antonio Di Stasi ◽  
Michelle Poon ◽  
Amir Hamdi ◽  
Hila Shaim ◽  
Susan Xie ◽  
...  
Keyword(s):  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Lymphocyte Subsets ◽  
T Cell Subsets ◽  
Cell Recovery ◽  
Cd8 Cells ◽  
Post Transplant

Abstract Abstract 4485 Allogeneic stem-cell transplantation (ASCT) is curative for many malignant and nonmalignant hematological disorders. Limitations of expanding this form of treatment are related primarily to non-relapse mortality (NRM) associated with reconstituting the recipient's immune system. We aimed to study reconstitution of lymphocyte subsets after matched and mismatched transplantation. Lymphocyte subsets (absolute numbers of CD3, CD4, CD8, CD19, CD56, CD25, CD45RA, CD45RO) were evaluated by flow cytometry at 1,3,6 and 12 months (mo) post-ASCT. Lymphocyte recovery was determined using means at each time point and group differences were assessed using analysis of variance. Kaplan-Meier survival curves were used to estimate time-to-event outcome measures and the log-rank test was used to evaluate differences between groups. 100 patients (pts) were included in the study. 25 pts received a matched sibling donor transplant (MSD), 20 pts a 10/10 MUD, 18 pts a 9/10 MUD, 9 pts a T cell depleted haploidentical (TCD haplo), and 28 a T cell replete haploidentical donor (TCR haplo). 53 pts received bone marrow and 47 had peripheral blood stem cells. Most patients were treated for acute leukemia (AML 41, ALL 23), 16 MDS, 6 CML, 4 CLL, 5 lymphoma. Median age was 43 years (range: 20–71). The median follow-up was 13.6 mo. 60 pts were alive and disease-free at last follow-up and 28 pts died 75% due to relapse. Non-relapse mortality (NRM) was 6% for the entire cohort. Overall, alive pts (vs who died) had higher mean CD3 (615 vs 349, p=0.03 on day 90), CD8 (427 vs 187, p=0.03 on day 90), CD4 (391 vs 54, p=0.01, on day 365) cells, and lower mean CD56 cells (178 vs 300, p=0.01, on day 30) post ASCT. Pts who progressed (vs did not), had lower 1 year mean CD4 cells (123 vs 394, p=0.02), lower mean CD3 cells (359 vs 1147, p=0.06), with no differences in CD8, NK, and CD45RA. NRM was associated with higher mean NK numbers at 6 months (499 vs 188, p=0.01) and with lower mean CD3 at day 90 (184 vs 557, p=0.07). T-cell recovery occurred most rapidly in MSD transplants (Figure1C), and compared with 10/10 MUD had higher mean CD3 cells in the first mo (1085 vs 510, p=0.01), CD4 in the first 6 mo (310 vs 147, p<0.01 day 180) and CD4CD45RA in the first 6 mo (105 vs 31, p=0.02 on day 180). Interestingly, we have found that higher CD4CD25 cell numbers recovered early and most rapidly in the MSD transplants, which may partly explain a lower incidence of GVHD in this group. Overall, TCR haplos had a similar pattern of T-cell recovery and outcomes as 10/10 MUDs (Figure1C-E). There was a significant delay in CD3 recovery between MSD and TCR haplos in the first 3 mo (mean 779 vs 483, p=0.04 on day 90), CD4 (mean 270 vs 170, p=0.03 day 90) and in the first 6 months for CD45RA (mean 105 vs 28, p=0.01 on day 180), while these differences were significant only at day 30 for CD8 cells (mean 703 vs 88, p<0.01). No significant differences in T cell subsets were found between 10/10 MUD and TCR HaploSCT for CD3, CD4, CD8, CD45RA and CD4CD25 for any time points. Of all types of transplant, TCD haplos had most impaired T-cell reconstitution and worst outcomes (Figure 1A and 1B). As previously reported it was characterized by rapid early NK cell recovery and delayed CD3, CD4, CD8 reconstitution. Interestingly, pts surviving 6–9 months post-transplant recovered CD3, C4, CD8 cells; however, naïve T-cell recovery remained impaired for more than 1 year post-transplant, suggesting that T cell recovery comes predominantly from the memory T cell compartment. In conclusion, these results suggest that recovery of lymphocyte subsets may vary widely with the type of transplant, may correlate with outcomes, and it is important to be further explored in this setting. Disclosures: No relevant conflicts of interest to declare.

Chemotherapy-Only Preparative Regimen for T-Cell Depleted Hematopoietic Stem Cell Transplantation of Patients with Fanconi Anemia From Alternative Donors

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3471-3471
Author(s):  
Farid Boulad ◽  
Stella M. Davies ◽  
David A. Williams ◽  
David A Margolis ◽  
Elizabeth G Klein ◽  
...  
Keyword(s):  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Fanconi Anemia ◽  
Refractory Anemia ◽  
Secondary Malignancies ◽  
Post Transplant ◽  
Preparative Regimen

Abstract Abstract 3471 Fanconi anemia (FA) is associated with a high risk of secondary malignancies, more specifically solid tumors. In allogeneic stem cell transplantation of the “non-Fanconi anemia host”, two factors have been consistently associated with increased risk of secondary malignancies post transplant and include graft-versus-host disease (GvHD) and radiation. The goal of reducing the risk of GvHD post transplant, has been achieved successfully with T-cell depleted transplants, as previously reported. Our second aim was to reduce the risk of radiation toxicity post transplant. We therefore initiated a multi-center trial using the fludarabine (Flu)/cyclophosphamide (Cy)/ATG cytoreduction backbone, and substituting busulfan (Bu) instead of radiation. This was followed by a CD34+ T-cell depleted peripheral blood stem cell graft. From June 2009 to July 2012, 27 patients, including 13 males and 14 females aged 4.3 – 31.4 (median 8.1), enrolled on this phase II multicenter protocol in 4 institutions. Indications for transplant included severe single lineage cytopenia (N=3), aplastic anemia (N=18) and myelodysplastic syndrome (N=6) - including refractory anemia RA (N=3), RA with excess blasts 1 RAEB1 (N=2), RAEB-2 (N=1). Prior treatment included transfusions (N=27) and androgens (N=12). Ten patients had a history of prior infections. Donors were Related mismatched (N=6) or Unrelated matched (N=16) or mismatched (N=5). Preparative regimen was: Bu 0.8–1.0 mg/Kg/dose Q 12H × 4 doses (days -7, -6), Cy 10 mg/Kg/day × 4, Flu 35 mg/m2/day × 4 days and Rabbit ATG 2.5 mg/Kg/day × 4 days (days -4 to -2). Patients also received filgrastim and GvHD prophylaxis with cyclosporine. Busulfan doses were adjusted to keep the steady state concentration below 350 in most cases. All grafts were T-cell depleted using the CliniMacs CD34 columns (Miltenyi). Cell doses of the grafts were: 3.1–42.7 × 106̂ CD34 cells/Kg and 2.2–49.9 × 103̂ CD3 cells/Kg. All 27 evaluable patients engrafted; one patient suffered a secondary graft failure. Two patients developed grade 1 and only one patient developed grade 2 GvHD. Grade 2–4 toxicity included mucositis (N=10), pulmonary toxicity (N=6), hepatotoxicity (N=6) with one patient developing hepatic veno-occlusive disease, renal toxicity (N=5), and hypertension (N=7). Infections included: CMV viremia (N=4), EBV viremias (N=1), clostridium difficile (N=1), bacteremia (N=5) and clostridium botulinum (N=1). Cause of death for four patients was acute respiratory failure (N=1), multi-organ failure (N=1), severe pulmonary hypertension (N=1) and infection (N=1). With a median follow-up of 7.9 months (range 0.5–37.8 months) 19 of 23 evaluable patients are alive and well (4 pts too early for outcome analysis). Although the study is ongoing an includes a relatively small number of patients with modest follow-up, the results appear promising. Engraftment, GVHD, early toxicity, infection and outcome data appear similar to historical TBI-based protocols. Further enrollment and longer follow up will define the comparative toxicity profile and relative risk of second tumor. Disclosures: Williams: bluebird bio: Consultancy; Wyeth: ; Takara bio:.

scholarly journals Letermovir Administration to Prevent Cytomegalovirus Reactivation Is the Potential Risk of Chronic Graft-Versus-Host Disease in Patients Who Received Haploidentical Stem-Cell Transplantation With Post-Transplant Cyclophosphamide

2021 ◽  
Vol 11 ◽  
Author(s):  
Toshiki Terao ◽  
Ken-ichi Matsuoka ◽  
Kentaro Narita ◽  
Takafumi Tsushima ◽  
Satoshi Yuyama ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Cell Recovery ◽  
Activated T Cells ◽  
Post Transplant ◽  
Hla Dr ◽  
Cmv Reactivation

The prevention of chronic graft-versus-host disease (cGVHD) is important for recipients of hematopoietic stem-cell transplantation (HSCT). As one of the etiologies, the relationship between early T-cell recovery and subsequent cGVHD development has been the focus of attention. Recently, letermovir (LTV) was approved for preventing cytomegalovirus (CMV) reactivation in the early transplantation phase. Although CMV affects the immune reconstitution after HSCT, the impacts of LTV to prevent CMV reactivation on early T-cell recovery and cGVHD have not been fully investigated. We aimed to identify early T-cell recovery under LTV at day 30 in 15 and 33 recipients from matched related donors (MRDs) and haploidentical donors with post-transplant cyclophosphamide (PTCy-haplo), respectively. Early increases in the levels of total lymphocytes and HLA-DR+ activated T-cells at day 30 were observed under CMV prophylaxis by LTV only in PTCy-haplo recipients and not in MRD recipients. Moreover, PTCy-haplo recipients with LTV showed a significantly higher incidence of cGVHD, but not acute GVHD. Our observations suggest that an early increase in the levels of HLA-DR+ activated T-cells may be implicated in the development of cGVHD in patients treated with PTCy who received LTV. Further studies are warranted to validate our results and elucidate the detailed mechanisms of our new insights.

New Developments in Allotransplant Immunology

Hematology ◽  
2003 ◽  
Vol 2003 (1) ◽  
pp. 350-371 ◽  
Author(s):  
A. John Barrett ◽  
Katayoun Rezvani ◽  
Scott Solomon ◽  
Anne M. Dickinson ◽  
Xiao N. Wang ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Immune Reconstitution ◽  
Cytokine Gene ◽  
Post Transplant ◽  
Cytokine Milieu ◽  
Cytokine Gene Polymorphisms

Abstract After allogeneic stem cell transplantation, the establishment of the donor’s immune system in an antigenically distinct recipient confers a therapeutic graft-versus-malignancy effect, but also causes graft-versus-host disease (GVHD) and protracted immune dysfunction. In the last decade, a molecular-level description of alloimmune interactions and the process of immune recovery leading to tolerance has emerged. Here, new developments in understanding alloresponses, genetic factors that modify them, and strategies to control immune reconstitution are described. In Section I, Dr. John Barrett and colleagues describe the cellular and molecular basis of the alloresponse and the mechanisms underlying the three major outcomes of engraftment, GVHD and the graft-versus-leukemia (GVL) effect. Increasing knowledge of leukemia-restricted antigens suggests ways to separate GVHD and GVL. Recent findings highlight a central role of hematopoietic-derived antigen-presenting cells in the initiation of GVHD and distinct properties of natural killer (NK) cell alloreactivity in engraftment and GVL that are of therapeutic importance. Finally, a detailed map of cellular immune recovery post-transplant is emerging which highlights the importance of post-thymic lymphocytes in determining outcome in the critical first few months following stem cell transplantation. Factors that modify immune reconstitution include immunosuppression, GVHD, the cytokine milieu and poorly-defined homeostatic mechanisms which encourage irregular T cell expansions driven by immunodominant T cell–antigen interactions. In Section II, Prof. Anne Dickinson and colleagues describe genetic polymorphisms outside the human leukocyte antigen (HLA) system that determine the nature of immune reconstitution after allogeneic stem cell transplantation (SCT) and thereby affect transplant outcomethrough GVHD, GVL, and transplant-related mortality. Polymorphisms in cytokine gene promotors and other less characterized genes affect the cytokine milieu of the recipient and the immune reactivity of the donor. Some cytokine gene polymorphisms are significantly associated with transplant outcome. Other non-HLA genes strongly affecting alloresponses code for minor histocompatibility antigens (mHA). Differences between donor and recipient mHA cause GVHD or GVL reactions or graft rejection. Both cytokine gene polymorphisms (CGP) and mHA differences resulting on donor-recipient incompatibilities can be jointly assessed in the skin explant assay as a functional way to select the most suitable donor or the best transplant approach for the recipient. In Section III, Dr. Nelson Chao describes non-pharmaceutical techniques to control immune reconstitution post-transplant. T cells stimulated by host alloantigens can be distinguished from resting T cells by the expression of a variety of activation markers (IL-2 receptor, FAS, CD69, CD71) and by an increased photosensitivity to rhodamine dyes. These differences form the basis for eliminating GVHD-reactive T cells in vitro while conserving GVL and anti-viral immunity. Other attempts to control immune reactions post-transplant include the insertion of suicide genes into the transplanted T cells for effective termination of GVHD reactions, the removal of CD62 ligand expressing cells, and the modulation of T cell reactivity by favoring Th2, Tc2 lymphocyte subset expansion. These technologies could eliminate GVHD while preserving T cell responses to leukemia and reactivating viruses.

106-P: Interaction of HLA KIR matching/mismatching with natural killer cell recovery in T cell depleted HLA identical stem cell transplantation

2007 ◽  
Vol 68 (1) ◽  
pp. S68
Author(s):  
Bipin N. Savani ◽  
Stephen Mielke ◽  
Sharon Adams ◽  
Marcela Uribe ◽  
Katayoun Rezvani ◽  
...  
Keyword(s):  
Stem Cell ◽  
T Cell ◽  
Natural Killer Cell ◽  
Stem Cell Transplantation ◽  
Natural Killer ◽  
Cell Transplantation ◽  
Killer Cell ◽  
Cell Recovery

Reduced Intensity Conditioning Therapy Using Campath -1H Is Successful for Stem Cell Transplantation in Non-Malignant Disorders.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1823-1823 ◽  
Author(s):  
Aarati Rao ◽  
Robert Hayashi ◽  
William Grossman ◽  
David Wilson ◽  
Lolie Yu ◽  
...  
Keyword(s):  
Stem Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Immune Suppression ◽  
Viral Infections ◽  
Normal Pregnancy ◽  
Promising Alternative ◽  
Cd8 Cells ◽  
Post Transplant ◽  
Cell Sources

Abstract Stem cell transplantation (SCT), indicated for many non-malignant disorders, is limited by donor availability, graft rejection (GR), toxicities of conditioning, morbidity and mortality (TRM), and graft versus host disease (GVHD). To overcome these barriers, we tested a novel conditioning for SCT. It was designed to support engraftment by deleting host immune reactive lymphocytes and macrophages. Campath -1H (anti-CD52 mab) was given on days -21, -20, and -19 (total dose 48 mg), fludarabine (day -8 to -4) (total 150 mg/m2) and melphalan on day -3 (140 [n=15] or 70 [n=1] mg/m2). Stem cell sources were related/unrelated bone marrow (BM) (8), peripheral blood (PB) (5) and umbilical cord blood (UCB) (3). GVHD prophylaxis was cyclosporine (tapered after 3 months), methylprednisone (tapered after day +28) and methotrexate on days +1, +3, and +6. Methotrxate was not used in UCBT. End points of the study included engraftment and TRM. Sixteen patients (1.5–40 yrs) diagnosed with aplastic anemia (5), Hurler’s (2), sickle cell anemia, XLAAD, histiocytosis (3), thalassemia, adrenoleukodystrophy, Evan’s syndrome and dyserythropoietic anemia were transplanted. Median follow-up was 219 days (66–845). The regimen was well tolerated. All patients that survived >1 month engrafted. Neutrophils (ANC >500/dL) engrafted at a median of 12.5 (10–36) days and platelets (>50,000/dL) at a median of 21 (12 –63) days. Skin GVHD developed in 3 patients and resolved early. Four are tapering immune suppression; 8 are successfully off immune suppression. All survivors have either stable disease or are cured. One recipient had a normal pregnancy and delivered twins. Two patients died prior to engraftment from previously acquired Pseudomonas infection. A third patient died of CMV disease (day +112) and another recipient died of intracranial hemorrhage/refractory thrombocytopenia (day +43) after engraftment. Other complications were bacterial and viral infections occurring within the first 100 days post-transplant. All but 1 CMV+ recipient reactivated CMV as assessed by PCR. Profound lymphopenia was present in all recipients on day +30. NK cells recovered by day +100, CD8+ cells by day +180, CD4+ and B cells between days 180–270 after transplant. Immunoglobulin (Ig M and A) levels dropped post transplant and normalized by 9 months. Ig A recovered later than IgM. In summary, successful engraftment despite varied stem cell sources, was achieved without significant toxicity or GVHD. Lymphopenia resulted in a significant infection risk within the first 100 days post transplant, requiring close surveillance and early intervention. This transplant regimen is well tolerated and may preserve fertility, making it a promising alternative to conventional SCT.

Allogeneic Stem Cell Transplantation in Angioimmunoblastic T-Cell Lymphoma (AITL): A Retrospective Survey from the Lymphoma Working Party (LWP) of the European Group for Blood and Marrow Transplantation (EBMT).

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3042-3042
Author(s):  
Charalampia Kyriakou ◽  
C. Canals ◽  
G. Taghipour ◽  
J. Finke ◽  
H. Kolb ◽  
...  
Keyword(s):  
Overall Survival ◽  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Relapse Rate ◽  
Allogeneic Stem Cell Transplantation ◽  
Cell Lymphoma ◽  
T Cell Lymphoma

Abstract AITL is a rare peripheral T-cell lymphoma characterised by an aggressive behaviour, which primarily affects the elderly. Chemotherapy regimens fail to alter the high relapse rate and overall survival hardly exceeds 25% at 5 years. To date, there is no information on the potential role of allogeneic stem cell transplantation (allo-SCT) in the management of AITL. We report the outcome of 39 patients with a median age of 47 years (24–68), who underwent an allo-SCT between 1995 and 2004 for AITL, and were reported to the EBMT registry. The median time from diagnosis to transplant was 10 months (4–72). Thirty-four patients (87%) had previously received two or more treatment lines, and 16 patients (41%) a previous autologous SCT. Fifteen patients (38%) had a primary refractory disease, 13 (33%) were transplanted in partial remission and the remaining patients were in complete remission (CR) (mostly in 2nd and 3rd CR). Twenty-four patients were transplanted from an HLA-identical sibling and 15 from a matched unrelated donor. A myeloablative conditioning regimen (MAC) was used in 21 patients (cyclophosphamide + total body irradiation in 14), while 18 patients received fludarabine-based reduced intensity conditionings (RIC). Peripheral blood was the source of stem cells in 35 patients (90%). Three patients failed to engraft (one patient in the RIC group). Twenty-one patients (54%) developed acute graft versus host disease (grade I-II, n=16; grade III-IV, n=5). Twenty-eight patients (72%) achieved a CR after the allogeneic procedure. Nine patients died from transplant related mortality (TRM) and 5 patients from disease progression. The cumulative incidence of TRM at 12 months was 19% for the MAC and 26% for the RIC group. After a median follow-up for the surviving patients of 20 months (6–74), 25 patients are alive. Relapse rates at 1 and 3 years were estimated at 10% and 18% for the MAC and 16 and 20% for the RIC patients. Progression free survival rates at 3 years were 67% and 50% and the overall survival at the same time 71% and 56% for the MAC and RIC group of patients, respectively. Although follow up is rather short, these data suggest that allo-SCT results in good overall response and is associated with a low relapse rate in this group of poor risk heavily pre-treated and rather elderly group of AITL patients. Allo-SCT could be considered a therapeutic option for eligible high-risk AITL patients. Nevertheless, the impact of this approach should be further explored in prospective collaborative studies.

Adoptive Immunotherapy with Tregs and Tcons Ensures Low TRM and a Low Incidence of Post Transplant Leukaemia Relapse After HLA Haploidentical Transplants for Acute Leukemia

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 154-154
Author(s):  
Mauro Di Ianni ◽  
Franca Falzetti ◽  
Alessandra Carotti ◽  
Adelmo Terenzi ◽  
Loredana Ruggeri ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
Adoptive Immunotherapy ◽  
Nk Cell ◽  
Haematological Toxicity ◽  
Post Transplant ◽  
Leukaemia Relapse

Abstract Abstract 154 In full haplotype mismatched (HLA-haploidentical) stem cell transplantation we showed adoptive transfer of freshly isolated donor CD4+CD25+ FoxP3+ T regulatory cells (Tregs) followed by donor T cells (Tcons) prevented acute and chronic GvHD without any post-transplant immunosuppression, promoted lymphoid reconstitution and improved immunity against opportunistic pathogens (Di Ianni et al., Blood 2011). The major drawback was the extra-haematological toxicity of the conditioning regimen which included TBI, thiotepa, fludarabine and cyclophosphamide. To reduce regimen related toxicity we replaced cyclophosphamide with alemtuzumab, given 22 days before the Treg infusion to prevent it from interfering with adoptive T cell immunotherapy (Fig 1). The graft consisted of immunoselected Tregs (median 2×106/kg; range 1.6–4.8; FoxP3+ cells 92% ± 8 SD;), CD34+ cells (median 9.1×106/kg; range 8.1–10.9) and Tcons (median 1×106/kg; range 0.5–3). No post-transplant prophylaxis against GvHD was given. Since May 2010 18 patients (median age 43 years, range 23–61) with high risk acute leukaemia (16 AML, 2 ALL) have been transplanted. All sustained full donor-type engraftment. Neutrophils reached 0.5×109/L at a median of 12 days (range 9–28 days). Platelets reached 20×109/L and 50×109/L at median of 12 and 15 days, respectively (range 10–36 days and 11–55 days). CD4+ and CD8+ peripheral blood counts reached, respectively, 50/μL medianly on days 36 (range 27 – 120 days) and 34 (range 15– 85); 100/μL medianly on days 55 (range 27 – 147 days) and 48 (range 27 – 114); 200/μL on days 62 (range 37 – 177 days) and 49 (range 28 – 147). We observed a rapid development of a wide T-cell repertoire with specific CD4+ and CD8+ T cells for opportunistic pathogen antigen such as Aspergillus, Candida, CMV, ADV, HSV, VZV, Toxoplasma. Treg immunotherapy did not compromise post-transplant generation of donor-vs-recipient alloreactive natural killer (NK) cell repertoires in patients who received transplants from NK alloreactive donors (Ruggeri et al., Science 2002). Three of 16 valuable patients developed acute GvHD. Two responded to a short course of immunosuppressive therapy and at present (288 and 360 days after transplant) are alive and well with very good immunological reconstitution. The 3rd patient died of infectious complications. Two other patients died of non-leukemic causes (1 fulminant hepatitis 17 days post-transplant, 1 pneumonia 14 days post-transplant). The incidence of TRM is 17% (3/18). As hoped, extra-haematological toxicity was mild. One AML patient, who received a transplant from a non-NK alloreactive donor, relapsed 77 days post-transplant. Fourteen of the 18 patients are alive and well at a minimum follow-up of 3 months. This study shows adoptive immunotherapy with freshly isolated, naturally occurring Tregs is a feasible option in HLA-haploidentical stem cell transplantation since alloantigen-specific Tregs were efficiently activated in vivo and controlled alloreactivity of at least 1×106/kg Tcons without clinically significant inhibition of general immunity. Moreover Treg infusion did not weaken the GvL effect. The incidence of post-transplant leukaemia relapse was surprisingly low as only 1 patient has relapsed to date and even in our previous series no patient who was transplanted in CR has relapsed at a median follow-up of 25 months. Infusion of high numbers of Tcons in the absence of post-transplant immunosuppression can be hypothesized to exert a GvL effect. In addition, in patients who were transplanted from NK alloreactive donors, preservation of alloreactive NK cell repertoires played a key role in reducing the incidence of relapse. Disclosures: No relevant conflicts of interest to declare.

Updated Long-Term Results of a Randomized Comparison of Prophylactic and Pre-Emptive Imatinib Following Allogeneic Stem Cell Transplantation for Philadelphia Chromosome Positive Acute Lymphoblastic Leukemia (Ph+ALL)

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 247-247 ◽  
Author(s):  
Heike Pfeifer ◽  
B. Wassmann ◽  
Wolfgang A. Bethge ◽  
Jolanta Dengler ◽  
Martin Bornhäuser ◽  
...  
Keyword(s):  
Stem Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Allogeneic Stem Cell Transplantation ◽  
Molecular Techniques ◽  
Long Term Results ◽  
Rt Pcr ◽  
Post Transplant

Abstract Abstract 247 Background: The presence of minimal residual disease (MRD) after allogeneic stem cell transplantation (SCT) for Ph+ ALL is highly predictive of eventual relapse. Imatinib (IM) has very limited efficacy in hematologic relapse of Ph+ALL, but may prevent leukemia recurrence if started when the leukemia burden is still very low and detectable only by molecular techniques. The optimal time for starting IM post transplant and the prognostic relevance of different bcr-abl transcript levels in relation to time after SCT have not been established. Aims: To determine the impact of post-transplant IM, given either prophylactically or after detection of bcr-abl transcripts (pre-emptively), on the overall incidence of MRD, remission duration, long-term treatment outcome and tolerability in pts. who underwent SCT for Ph+ALL in complete remission. Study Design: In a prospective, randomized multicenter trial, previously transplanted Ph+ ALL pts. (n=55) were assigned to receive imatinib prophylactically (n=26) or pre-emptively (n=29). SCT was performed in CR1 in 23 pts. and 27 pts. in the two groups, respectively. Five pts.were transplanted in CR2. Serial assessment of bcr-abl transcripts was performed by quantitative RT-PCR and additionally by nested-RT-PCR if the sensitivity of the qRT-PCR was below the quantitative range. Confirmatory testing of a second independent sample was not required, to reduce the risk of treatment delays. Samples were considered PCR negative only if the ABL copy number exceeded 104. Imatinib administration was scheduled for one year of continuous PCR negativity. Results: IM was started in 24/26 pts. allocated to prophylactic IM and in 14/29 pts. in the pre-emptive arm. The majority of pts. received IM 400 mg/d (26/38 pts.), the other 12 pts. 600 mg IM daily. IM was started a median of 48 d after SCT in the prophylactic arm and 70 d after SCT with pre-emptive therapy. After a median follow-up of 30 mos. and 32 mos., respectively, 82% and 78% of pts. are alive in ongoing CR, 4 pts. died in CR. Five pts. transplanted in CR1 and 2/5 pts. transplanted in CR2 have relapsed (median follow-up 9 mos. and 10.5 mos., respectively). The frequency of MRD positivity was significantly lower in pts. assigned to prophylactic imatinib (10/26; 40%) than those in the pre-emptive treatment arm (20/29; 69%) (p=0.046 by chi2 test). Only 9 of 29 pts. assigned to pre-emptive imatinib remained continuously PCR negative after SCT, with a median follow-up of 32 months (18–46 months) after SCT. The median duration of sustained, uninterrupted PCR negativity after SCT is 26.5 months with prophylactic and 6.8 months with pre-emptive administration of imatinib (p=0.065). The probability of remaing in CHR after SCT was significantly lower in partients who remained MRD negative after SCT (p=0.0002). Analysis of the kinetics of molecular relapse showed that detection of bcr-abl transcripts within 100 days of transplant, despite rapid initiation of IM, was associated with a significantly inferior EFS compared to first detection of MRD positivity more than 100 days after SCT. IM was discontinued prematurely in 54% pts. receiving imatinib prophylactically and in 64% of pts. receiving imatinib pre-emptively, mostly due to gastrointestinal toxicity. Accordingly, the time to IM discontinuation was 245 d and 191 d in the prophylactic and the pre-emptive treatment arms, respectively. Despite this early discontinuation rate, overall survival in the two treatment groups was 80% and 74.5% after 5 years, with no significant difference by log rank test (p=0.84). Conclusions: Prophylactic administration of imatinib significantly reduces the incidence of molecular relapse after SCT. Both interventional strategies are associated with a low rate of hematologic relapse, durable remissions and excellent long-term outcome in patients with Ph+ ALL. The presence of MRD both prior to and early after SCT identifies a small subset of patients with a poor prognosis despite post-transplant imatinib, and warrants testing of alternative approaches to prevent hematologic relapse. Disclosures: Schuld: Novartis: Employment. Goekbuget:Micromet: Consultancy. Ottmann:Novartis Corporation: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding.

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