Head-to-Head Comparison of Haploidentical HSCT Strategies for Hematologic Malignancies: Phase III Hatcy Study of T-Cell-Depleted HSCT with Adjunctive ATIR101 Versus T-Cell-Replete HSCT with Post‐Transplant Cyclophosphamide

Rationale: Haploidentical allogeneic hematopoietic stem cell transplantation (haplo HSCT) is increasingly used for the treatment of high-risk hematologic malignancies and overcomes limitations of finding a human leukocyte antigen (HLA)-matched donor in a timely manner. Although the most frequently used approach is a T-cell-replete stem cell source followed by in vivo depletion of alloreacting T cells using post-transplant chemotherapy with cyclophosphamide (PTCy), several other approaches have emerged, providing selected or manipulated donor-derived T cells to a T-cell-depleted or alpha/beta T-cell-CD19-depleted stem cell backbone. Here, we present the approach involving T-cell-depleted haplo HSCT complemented by ATIR101, an adjunctive infusion consisting of ex vivo selectively allodepleted, donor-derived, T-cell-enriched leukocytes. ATIR101 can facilitate early immune protection and provide anti-infectious and anti-leukemic activity while minimizing the risk of acute and chronic graft-versus-host disease (GVHD) without the need for post-transplant immunosuppression. ATIR101 is manufactured through the ex vivo use of TH9402 (a rhodamine derivative) and photodynamic treatment, selectively depleting the donor T cells that were activated by the recipient cells. The safety and efficacy of ATIR101 treatment following T-cell-depleted haplo HSCT have been investigated in Phase I and II studies in patients with hematologic malignancies (Roy DC et al. Br J Haematol 2019; ASH 2016, 2018). This strategy is currently being explored in a large, global, randomized Phase III study against a strategy of T-cell-replete HSCT with PTCy as the most commonly applied approach in haplo HSCT. Trial Overview: A randomized, multicenter, open-label Phase III trial (HATCY; CR‐AIR‐009; NCT02999854) is currently enrolling 250 patients with acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), or myelodysplastic syndrome (MDS) to undergo either T-cell-depleted haplo HSCT with adjunctive ATIR101 treatment or T-cell-replete haplo HSCT with PTCy. Trial Design and Methods: Inclusion and exclusion criteria are listed in Table 1. All patients undergo total body irradiation (TBI) or non-TBI myeloablative conditioning. Patients in the ATIR101 arm receive anti-thymocyte globulin (Sanofi, 2.5 mg/kg once daily for 4 days) prior to HSCT and an ATIR101 infusion at a dose of 2 × 106 viable T cells/kg between 28 and 32 days post HSCT. In this group, no post-HSCT immune suppression is administered. Patients in the PTCy arm receive cyclophosphamide (50 mg/kg) on Day 3 and 4 (or 5) post HSCT, with subsequent use of immune suppression for GVHD prophylaxis based on institutional guidelines. The primary endpoint of the study is GVHD- and relapse-free survival (GRFS), a composite endpoint defined as time from randomization until Grade III/IV acute GVHD, chronic GVHD requiring systemic immunosuppressive treatment, disease relapse, or death, whichever occurs first. GRFS was selected because it encompasses overall post-transplant health status, thereby closely reflecting a successful transplant outcome (Holtan SG, Blood 2015). Key secondary endpoints are overall survival, progression‐free survival, relapse‐related mortality, and transplant‐related mortality. A further objective of the study is to compare the effects of the two treatment strategies on quality of life. Approximately 50 sites are planned globally. The analysis is event driven: an interim analysis is planned at 105 GRFS events and the final analysis at 156 GRFS events. All patients will be followed up for at least 24 months post HSCT. Conclusion: This study will determine whether a strategy with a T-cell-depleted HSCT with adjunctive ex vivo selectively allodepleted, donor-derived, T-cell-enriched leukocytes (ATIR101) results in improved outcomes over a strategy with T-cell-replete HSCT with PTCy in patients undergoing haploidentical transplantation. The use of GRFS as a composite endpoint involving freedom of relapse and severe GVHD will allow a unique health-economic assessment and definition of value-based healthcare. Disclosures Roy: Kiadis Pharma: Other: Travel support; University of Montreal: Patents & Royalties: Author on patent; Hopital Maisonneuve-Rosemont: Patents & Royalties: Author on patent. Sanson:Kiadis Pharma: Employment. Hylton:Kiadis Pharma: Employment. Sandler:Kiadis Pharma: Employment. Mielke:Miltenyi: Consultancy, Honoraria, Other: Travel and speakers fee (via institution), Speakers Bureau; IACH: Other: Travel support; DGHO: Other: Travel support; Kiadis Pharma: Consultancy, Honoraria, Other: Travel support (via institution), Speakers Bureau; EBMT/EHA: Other: Travel support; Bellicum: Consultancy, Honoraria, Other: Travel (via institution); Celgene: Honoraria, Other: Travel support (via institution), Speakers Bureau; GILEAD: Consultancy, Honoraria, Other: travel (via institution), Speakers Bureau; ISCT: Other: Travel support; Jazz Pharma: Honoraria, Other: Travel support, Speakers Bureau.

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Selective Allodepletion by TH9402-Mediated Photosensitization Results in Early Full Donor T Cell Reconstitution in the Absence of High-Grade, Acute GvHD and Is Associated with Favorable Outcome after HLA Matched Sibling SCT for Hematologic Malignancies

Blood ◽

10.1182/blood.v112.11.1168.1168 ◽

2008 ◽

Vol 112 (11) ◽

pp. 1168-1168

Author(s):

Stephan Mielke ◽

Aarthi Shenoy ◽

Vicki S. Fellowes ◽

Katayoun Rezvani ◽

Bipin N. Savani ◽

...

Keyword(s):

T Cells ◽

Stem Cell ◽

T Cell ◽

High Risk ◽

Ex Vivo ◽

Chronic Gvhd ◽

Hematologic Malignancies ◽

Infectious Complications ◽

High Risk Population ◽

Donor T Cells

Abstract Selective allodepletion (SD) is a strategy to eliminate host-reactive donor T-cells from allografts to prevent graft versus host disease (GvHD) while conserving useful donor immunity. We developed a semi-closed, GMP-quality, clinical scale SD process where donor-derived lymphocytes are stimulated with patient-derived T-cell antigen presenting cells in an ex vivo mixed lymphocyte reaction (MLR). Alloactivated donor T cells preferentially retain the photosensitizer 4,5-dibromorhodamine 123 (TH9402), rendering them susceptible to elimination by exposure to visible light in a photodepletion device (Kiadis Pharma Inc, The Netherlands). After Food and Drug Administration and Institutional Review Board approval we initiated a clinical trial where HLA-identical sibling recipients with hematological (non T-cell) malignancies received a CD34-cell selected transplant (Miltenyi, Germany) containing less then 1 × 104 T cells/kg together with 5 × 106/kg viable SD donor T cells on day 0, using an age-adapted, radiation-based preparative regimen (FluCyTBI). Low-dose cyclosporine was used as sole immunosuppression in the absence of GvHD. Eleven patients (median age 43 (28–68) years with ALL, MDS, CML, mantle cell lymphoma (MCL), or AML) were transplanted with a median follow-up of 240 (43–400) days. Nine patients were considered high risk. Patients received a stem cell product containing a median of 6.0 (3.9–9.5) ×106/kg CD34+ stem cells in addition to 5×106/kg SD T cells. Absolute lymphocyte recovery was rapid (median 834 (384–2486) cells/μL day 30 post transplant) [Fig A]. Early T cell chimerism was donor-dominated (median 66% (6–95) on day 14, and 97% (82–100) on day 30, and 100% (92–100) on day 45 [Fig B]. One patient received an unmanipulated DLI to treat a delayed fall in T cell chimerism. Three patients developed steroid-sensitive grade II aGvHD of skin (N=2) and gut (N=1) but no grade III–IV aGvHD occurred after transfusion of the photodepleted lymphocytes [Fig C]. Two patients developed limited chronic GvHD. Only one patient, transplanted for refractory MCL, relapsed 340 days after transplant. One patient died of infectious complications and GvHD 330 days after transplant after receiving an unmanipulated DLI in her home country for suspected, but subsequently unconfirmed relapse. Eight patients reactivated CMV but were successfully treated. These results demonstrate for the first time clinical feasibility of photodepletion-based SD stem cell allotransplants in matched siblings. Robust lymphocyte recovery and early donor chimerism with a low relapse incidence in a high-risk population suggest functionality of SD T cells in the absence of severe GvHD, which should allow further reduction of immunosuppression to optimize disease control in future studies.

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Distinct Biomarker Profiles in Ex-Vivo T Cell Depletion Graft Manipulation Strategies: CD34+ Selection Vs CD3/19 Depletion in Matched Sibling Allogeneic Peripheral Blood Stem Cell Transplantation

Blood ◽

10.1182/blood.v128.22.657.657 ◽

2016 ◽

Vol 128 (22) ◽

pp. 657-657

Author(s):

Caroline R. Cantilena ◽

Sawa Ito ◽

Xin Tian ◽

Prachi Jain ◽

Fariba Chinian ◽

...

Keyword(s):

T Cells ◽

Stem Cell ◽

T Cell ◽

Stem Cell Transplantation ◽

Cumulative Incidence ◽

Acute Gvhd ◽

Ex Vivo ◽

Post Transplant ◽

Matched Sibling ◽

Cd34 Selection

Abstract INTRODUCTION: Ex-vivo T cell depletion strategies have been widely used to reduce the incidence of graft versus host disease (GVHD) in allogeneic stem cell transplantation (allo-SCT). Although several options of ex-vivo graft manipulation strategy are available, direct comparison between strategies along with relevant biomarkers has been lacking. Here we evaluated cellular and plasma biomarkers in two separate graft manipulation strategies, CD3-CD19 depletion versus CD34+ selection using the Miltenyi CliniMACS and their association with clinical outcomes. METHODS: Forty two subjects with hematological malignancies underwent HLA matched sibling allo-SCT at a single center between 2012 and 2015 and received either an ex-vivo CD3-CD19 depleted, CD34+ negatively selected graft (CD3/19D, n=20) or an ex-vivo CD34+ cell positively selected graft (CD34S, n=22). Both cohorts were treated with the same conditioning regimen of cyclophosphamide, fludarabine, and total body irradiation (600-1200 cGy) and GVHD prophylaxis of low dose cyclosporine. Peripheral blood mononuclear cells and plasma samples were collected at days 14 or 30, 60, 100 post-transplant. Post-transplant cellular immune reconstitution was evaluated by multi-color flow cytometry immunophenotyping, characterizing the subsets of memory T cells, regulatory T cells (Tregs), natural killer (NK) cells, and B cells with various functional markers. The plasma levels of ST2, Reg3α, and sTNFR1 were measured using enzyme-linked immunosorbent assay (ELISA). RESULTS: The median age at transplant was 48 years (range 17-70) in CD3/19D and 45 years (11-73) in CD34S. At a median follow up of 37 months in CD3/19D and 22 months in CD34S, the major clinical outcomes were similar between two groups; the overall survival (70% and 86%), non-relapse mortality (5% and 4.5%), and cumulative incidence of relapse (35% and 39%) at 2 years, respectively. Two subjects in CD3/19D developed late engraftment failure before day 100 but all other subjects achieved primary neutrophil and platelet recovery. Unexpectedly, the cumulative incidence of grade II-IV acute GVHD was higher in CD3/19D (61%) in comparison to the incidence in CD34S (32%, P=0.07, Figure). The cumulative incidence of extensive chronic GVHD was 33% in CD3/19S and 24% in CD34S. The fraction of Helios negative Tregs post-transplant was significantly lower in CD3/19D (median [interquartile range]: 10.4% [7.1-16.4] at day 30; 4.9% [3.0-8.3] at day 60) compared to CD34S (23.8% [10.7-35.8], P=0.03 at day 30; 8.8% [6.8-18.4], P=0.01 at day 60, Figure). Plasma ST2 levels were significantly higher in CD3/19D (45ng/mL [27-67] at day 14; 33ng/mL [27-62] at day 28) in comparison to CD34S (29ng/mL [19-40], P=0.03 at day 14; 25ng/mL [14-33], P=0.03 at day 28, Figure). In addition, significantly higher CD4 naive T cells, lower effector memory and PD-1 bright CD4 T cells were observed in CD3/19D in comparison to CD34S. NK and B cell profiles were not significantly different between the two groups. CONCLUSION: Both methods of ex vivo TCD were associated with extremely low NRM rates (~5%).We observed a higher cumulative incidence of acute GVHD in the recipients of CD3/19 depleted grafts, accompanied with the distinct biomarker profiles of poor Treg reconstitution and high level of ST2. CD3/19 depletion may have disproportionately depleted Tregs in the graft, leading to uncontrolled tissue damage and GVHD evidenced by higher ST2 levels. Further validation is required to confirm the utility of monitoring Treg reconstitution and ST2 level as biomarkers to predict the outcomes of T cell depleted allo-SCT. Figure 1. Figure 1. Disclosures Battiwalla: NIH/NHLBI: Employment.

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UM171-Expanded Cord Blood Transplants Support Robust T-Cell Reconstitution with Low Rates of Severe Infections

Blood ◽

10.1182/blood-2020-139598 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 36-37

Author(s):

Maude Dumont-Lagacé ◽

Qi Li ◽

Mégane Tanguay ◽

Jalila Chagraoui ◽

Tibila Kientega ◽

...

Keyword(s):

T Cells ◽

Stem Cell ◽

T Cell ◽

Cord Blood ◽

Immune Reconstitution ◽

Post Transplant ◽

T Cell Reconstitution ◽

Significant Difference ◽

Severe Infections ◽

Related Mortality

Introduction Rapid T cell reconstitution following hematopoietic stem cell transplantation is essential for protection against infections and has been associated with lower incidence of chronic graft-vs-host disease (cGVHD), relapse and transplant-related mortality (TRM). While cord blood (CB) transplants are associated with lower rates of cGVHD and relapse, their low stem cell content results in slower immune reconstitution and higher risk of graft failure, severe infections and TRM. Recently, results of a Phase I/II trial revealed that single UM171-expanded CB transplant allowed the use of smaller CB units without compromising engraftment. We now report on T cell reconstitution and immune function in patients transplanted with UM171-expanded CB grafts. Methods We performed a retrospective analysis of 20 patients treated with UM171-expanded CB and compared it to a contemporary cohort of 12 patients treated in the same institution who received unmanipulated CB transplant with similar conditioning regimens. Of note, no patient received ATG as part of the conditioning in either cohort. We used flow cytometry and TCR sequencing to evaluate T cell reconstitution, and virus-specific ELISpot assays to evaluate T cell function in the first year post-transplantation. We also categorized infectious events as per definitions of infection severity in the BMT CTN Technical MOP Version 3.0 and report the mean cumulative count of infectious events for each cohort. Results While median T cell dose in graft was at least 2-3x lower for the cohort of patients treated with UM171-expanded CB due to the selection of smaller cords and to cell loss occurring during CD34 selection process, numbers and phenotype of T cells at 3, 6 and 12 months post-transplant were similar in patients treated with UM171-expanded or unmanipulated CB transplant. TCR sequencing analyses revealed that UM171 patients had greater T cell diversity and higher numbers of T cell clonotypes at 12 months post-transplant compared to patients who received unmanipulated CB. Younger UM171 patients (i.e. <40 years old) also showed a more pronounced increase in naïve T cells and recent thymic emigrants (RTE) between 3- and 12-months post-transplant compared to age-matched unmanipulated CB patients, suggesting that UM171-expansion improves thymopoiesis at least in the young patients. This also correlated with the demonstration that UM171 expands common lymphoid progenitors in vitro. ELISpot assays revealed that UM171 patients showed early virus-specific T cell reactivity, at 2- and 3-months post-transplant. Most importantly, UM171 patients had a 2-fold lower frequency of severe (i.e. grade 2-3) infections at 1 year post-transplant, even though time to engraftment of 500 neutrophils was similar between the two cohorts (17 and 20 days for the UM171-expanded and unmanipulated CB cohorts respectively, p=0.94). Conclusion Our data show that the relative T-cell paucity of the UM171 graft is rapidly compensated after transplant with no significant difference observed between the two cohorts in terms of numbers and phenotypes of T cells at 3, 6 or 12 months post-transplant. Although it is difficult to dissect the relative contribution of homeostatic expansion and de novo thymopoiesis, recipients of UM171 grafts had a greater TCR diversity at one year, which was more evident among patients younger than 40 years of age. The prompt immune reconstitution observed in UM171 patients translated into a low rate of severe (grade 2-3) infections and no infection-related mortality. These results support rapid and functional T cell reconstitution following UM171 expanded CB transplantation, which likely contributes to the absence of moderate/severe cGVHD, infection-related mortality and late TRM observed in this cohort. Figure legend: Mean cumulative counts of infectious events in patients transplanted with UM171-expanded (blue) or unmanipulated (red) CB. Mean cumulative counts are shown for all infectious events (A), bacterial (B) and viral (C) infections. Events were categorized by type and severity as per BMT CTN guidelines (Appendix 4A). Infectious events of grade 1-3 are shown in pale colors, while more severe events (grade 2-3) are shown in dark colors. Censored patients (including those who relapsed) are indicated with white circles. Figure 1 Disclosures Dumont-Lagacé: ExCellThera: Current Employment. Busque:Novartis: Honoraria; BMS: Honoraria; Pfizer: Honoraria. Sauvageau:ExCellThera: Current equity holder in private company, Other: CEO, Patents & Royalties. Cohen:ExCellThera: Consultancy, Other: principal investigator of an ongoing UM171 clinical trial.

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Phase I Clinical Study of Donor Lymphocyte Infusion Depleted of Alloreactive T Cells after Haplotype Mismatched Myeloablative Stem Cell Transplantation To Limit Infections and Malignant Relapse without Causing GVHD.

Blood ◽

10.1182/blood.v108.11.309.309 ◽

2006 ◽

Vol 108 (11) ◽

pp. 309-309 ◽

Cited By ~ 3

Author(s):

Denis-Claude Roy ◽

Sandra Cohen ◽

Lambert Busque ◽

Douglas Fish ◽

Thomas Kiss ◽

...

Keyword(s):

T Cells ◽

Stem Cell ◽

T Cell ◽

High Risk ◽

Phase I ◽

Acute Gvhd ◽

Hematologic Malignancies ◽

Infectious Complications ◽

Cell Transplant ◽

Post Transplant

Abstract Patients with very high risk hematologic malignancies who cannot find an HLA-matched related or unrelated donor can benefit from haplo-mismatched transplantation. The latter is, however, complicated by frequent and severe infectious complications and disease relapse due to delayed immune reconstitution. We have previously reported that photodynamic therapy (PDT) could selectively deplete donor alloreactive populations while preserving lymphocytes for immune responses. Indeed, the dibromorhodamine derivative TH9402 (Celmed BioSciences) has a propensity to accumulate in activated but not resting T cells. We present results of an ongoing Phase I clinical trial of haplo-mismatched allogeneic stem cell transplant (SCT) supplemented with donor lymphocyte infusions (DLIs) PDT depleted of host-reactive T cells. Nine high-risk patients with hematologic malignancies (5 AML relapsed or refractory, 2 MDS, 1 NHL relapsing after autologous SCT, 1 refractory CLL) entered the trial, 7 are evaluable for acute GVHD and reconstitution. Patients (4 M, 3 F) underwent transplantation with donor cells mismatched at 3 HLA Ags: 2 patients; 2Ags: 4 pts, and DR only: 1 pt). Donor mononuclear cells (MNCs) were incubated with recipient MNCs for 4 days, exposed to TH9402 PDT, stored frozen, and administered on day 30±3 after transplant at 3 graded DLI dose levels: 1×104 (1pt), 5×104 (3pts), and 1.3 x105 (3pts) CD3+ cells/kg. Anti-host cytotoxic T lymphocyte precursors (CTLp) were depleted from DLIs by approximately 1.5 logs, and flow cytometry showed greater than 90% elimination of activated T cells (CD4+CD25+ and CD8+CD25+) by TH9402 PDT. All stem cell grafts underwent in vitro immunomagnetic T cell depletion using CD34+ positive cell selection (Miltenyi). Median age at SCT was 57 years (range: 40–58). Five patients were in partial remission or had progressive disease, and 2 patients were in complete remission at the time of SCT. The myeloablative regimen consisted of TBI (1200 cGy), thiotepa (5 mg/kg) and fludarabine (40 mg/m2/day for 5 days) followed by infusion of CD3 depleted HSC grafts. A median of 9.2×106 CD34+ cells/kg were infused on day 0. No GVHD prophylaxis was administered. Evaluable patients showed durable hematologic engraftment: median time to >0.5×109 granulocytes/L was 10.5 days (8–20), and to >20×109 platelets/L without transfusion, 12 days (9–137) and achieved complete donor chimerism. No patient developed acute GVHD (grade II–IV), while 3 patients developed signs of chronic GVHD. Two patients died: one (cohort 1) of a post-transplant lymphoproliferative disease, and one (cohort 2), of relapsed AML. No other patient relapsed. Two pts (1 in cohort 2 and 1 in cohort 3) recovered greater than 0.3×109 CD3+ and CD4+ cells/L at 2 and 5 months post-DLI, and 4 pts had >0.2×109 CD3+ cells/L at 6 mo post-DLI. Although 4 patients developed infectious complications (HSV, CMV, Nocardia, Aspergillus), all resolved rapidly with appropriate therapy. The overall disease-free-survival and survival are 57% at 1 year (median follow-up: 9.4 mo). Our results indicate that the post-transplant infusion of a PDT treated DLI is feasible, does not induce acute GVHD, and may accelerate T cell reconstitution. This PDT strategy could represent an appealing alternative for patients in the higher age range who are at high risk for GVHD.

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Expansion of Lymphocytes for Cell-Based Therapeutics

Blood ◽

10.1182/blood.v116.21.sci-48.sci-48 ◽

2010 ◽

Vol 116 (21) ◽

pp. SCI-48-SCI-48

Author(s):

Helen E. Heslop

Keyword(s):

T Cells ◽

Stem Cell ◽

T Cell ◽

Adoptive Transfer ◽

Ex Vivo ◽

Nasopharyngeal Cancer ◽

Suicide Gene ◽

Phase Iii ◽

Hemopoietic Stem Cell ◽

Cell Transplant

Abstract Abstract SCI-48 Adoptive transfer of T cells can lead to targeted and long-lived anti-tumor or anti-infective activity and can also modulate alloreactivity. T cell therapies have been used in both autologous and allogeneic settings. Donor-derived cytotoxic specific T lymphocytes (CTLs) have already proved highly effective in preventing or treating viral infections and Epstein-Barr virus (EBV) lymphomas developing after allogeneic hemopoietic stem cell transplant while T cells expanded ex vivo with CD3/28 beads have enhanced immune reconstitution after autologous stem cell transplantation. Clinical responses have also been observed following T cell therapy in patients with melanoma, lymphoma or nasopharyngeal cancer. Although successes have been obtained, these studies have also provided insights into the requirements for more effective cellular immunotherapy, which may be obtained by genetic modification of T cells. Approaches under evaluation in the clinic include transfer of artificial T cell receptors to target tumor cells, transfer of genes to render T cells resistant to tumor evasion mechanisms and transfer of a suicide gene that can be activated should adverse effects occur to allow the cell to be destroyed on exposure to a specific signal. The suicide gene strategy using the herpes simplex viral thymidine kinase (Tk) gene allows ablation of infused donor T cells if they induce graft-versus-host disease after allogeneic HSCT and has reached phase III clinical trial. In all these adoptive T cell immunotherapy strategies, broader application is limited by suboptimal persistence of transferred T cells, and by the complexity of current manufacturing techniques. Current research focuses on defining the optimum type of cell for transfer and the ex vivo selection and expansion procedures that favor long term persistence, since broader applicability will require ex vivo expanded T cells to show clinical activity and to have robust manufacturing processes and a clinical distribution paradigm. Strategies for simplifying and accelerating manufacture of T cell products have included the use of artificial antigen presenting cells expressing co-stimulatory ligands to provide a rapid source of antigen and optimized costimulation; bioreactors to grow cells in a closed system; and cytokine combinations to optimize cell growth and survival. Integration of these multiple approaches will be required to determine the best cell type and culture conditions for generating T cells for subsequent adoptive transfer into a complex immune network. Disclosures: Off Label Use: T cell products in studies conducted under INDs.

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New Developments in Allotransplant Immunology

Hematology ◽

10.1182/asheducation-2003.1.350 ◽

2003 ◽

Vol 2003 (1) ◽

pp. 350-371 ◽

Cited By ~ 39

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.

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Generation of Regulatory T Cells through Intravenous Delivery of Autologous Apoptotic Cells.

Blood ◽

10.1182/blood.v104.11.2390.2390 ◽

2004 ◽

Vol 104 (11) ◽

pp. 2390-2390

Author(s):

David Peritt ◽

Kim Campbell ◽

Amy Krutsick ◽

Janine Huber ◽

Ulrich Thienel ◽

...

Keyword(s):

T Cells ◽

Dendritic Cells ◽

T Cell ◽

Regulatory T Cells ◽

Immune Responses ◽

Ex Vivo ◽

Contact Hypersensitivity ◽

Phase Iii ◽

Apoptotic Cells ◽

Phase Ii Trials

Abstract Extracorporeal photopheresis (ECP) is approved for the palliative treatment of skin manifestations associated with cutaneous T cell lymphoma. As reported in the literature, ECP has shown promise as a treatment for such immune-mediated inflammatory disorders as graft versus host disease, transplantation rejection, and autoimmune diseases. ECP involves the reinfusion of autologous, apoptotic peripheral blood leukocytes treated ex vivo with 8-methoxypsoralen (8-MOP) and UVA light. The biological mechanism of action of ECP, however, remains unresolved. We have evidence to suggest that delivery of ECP-treated apoptotic cells modulates immune responses, possibly through generation of regulatory T cells. When co-incubated with ECP-treated cells, activated dendritic cells produce reduced levels of proinflammatory cytokines, such as IL-12, while TGFβ levels were modestly increased. Activation of CD4+ T cells in the presence of allogeneic dendritic cells and ECP-treated cells promotes generation of a population of T cells that can suppress proliferation of, and IFNγ production by, naïve syngeneic T cells. To confirm these findings in vivo, we employed a murine contact hypersensitivity model. ECP-treated or control spleen and lymph node cells from mice sensitized with the hapten dinitrofluorobenzene (DNFB) were injected intravenously into naïve recipients. Compared to controls, mice that received ECP-treated cells demonstrated significantly less ear swelling following sensitization and challenge with DNFB. Suppression of ear swelling was specific for DNFB and cell-mediated, as demonstrated by the ability to transfer DNFB tolerance to naïve mice, which could appropriately respond to the unrelated hapten oxazalone. Transfer of this tolerance was abrogated by depletion of either CD4+ or CD25+ T cell populations. Collectively, these results suggest that delivery of ECP-treated cells promotes the generation of regulatory T cells that are capable of modulating immune responses. Therakos sponsored Phase II trials for the prevention and treatment of GvHD are concluding and an international blinded pivotal phase III study is planned for 2005.

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Haploidentical Stem Cell Transplantation with CD3 Depleted Mobilized Peripheral Blood Stem Cell Grafts for Children with Hematologic Malignancies.

Blood ◽

10.1182/blood.v106.11.2910.2910 ◽

2005 ◽

Vol 106 (11) ◽

pp. 2910-2910 ◽

Cited By ~ 9

Author(s):

Gregory A. Hale ◽

Kimberly A. Kasow ◽

Kwan Gan ◽

Edwin Horwitz ◽

Joseph P. Woodard ◽

...

Keyword(s):

Stem Cell ◽

T Cell ◽

Stem Cell Transplantation ◽

Graft Rejection ◽

Peripheral Blood ◽

Acute Gvhd ◽

Ex Vivo ◽

Hematologic Malignancies ◽

Infectious Complications ◽

Persistent Disease

Abstract Allogeneic hematopoietic stem cell transplantation is the only curative therapy for patients with high-risk or recurrent hematologic malignancies. As only 25% of patients have matched siblings and not all have unrelated donors, haploidentical HSCT using mismatched related donors is the only option for many patients. However, historically the risks of GVHD, graft rejection, and prolonged immunocompromise have made this donor option rather limited. More recently, highly purified CD34+ hematopoietic cells have been used with decreased GVHD rates, but at the risk of graft rejection and prolonged immunodsuppression with infectious complications. In an attempt to obtain a PBSC graft with higher T-cell content to maintain acceptable GVHD rates while promoting more rapid immune reconstitution, we initiated a prospective clinical trial for patients with hematologic malignancies who lacked a matched related donor or unrelated donor using a novel method of graft processing. The conditioning regimen consisted of TBI (12 Gy in 8 fractions over 4 days), cyclophosphamide (60 mg/kg/day for 2 days), thiotepa (10 mg/kg/day for 1 day), and rabbit ATG (10 mg/kg/course over 4 days). GVHD prophylaxis consisted of cyclosporine initiated at day -2. G-CSF mobilized PBSC grafts from mismatched related donors were infused after ex vivo T-cell depletion using OKT3 on the CliniMACS device. Patients had weekly peripheral blood analysis for evidence of EBV, CMV, or adenovirus DNA by PCR. If positive, pre-emptive therapy was administered. Twenty patients were enrolled with a median age of 11.9 yrs (range, 2.7–22.1). Diagnoses included ALL (2-CR1, 5-CR2, 3-CR3), AML (2-CR1, 1-CR2, 1-persistent disease), MDS (1-CR1, 2-persistent disease), CML (2- first chronic phase) and NHL (1-CR2). Donors and recipients were matched at 3 (n=11), 4 (n=8) or 5 (n=1) of 6 HLA loci. Of the 19 evaluable patients (one patient died prior to engraftment), the median time to attain ANC > 500/mm3 was 13 days (range, 10–19) and the median time to attain a transfusion-independent platelet count of 50,000/mm3 was 18 days (range, 8–37) post-HSCT. Only 3 patients developed grade 1–2 acute GVHD and none developed grade 3–4 acute GVHD. One patient developed limited chronic GVHD. Complications included post-transplant lymphoproliferative disorder (PT-LPD, n=3), VOD (n=2), BOOP (n=1), CMV retinitis (n=1), and adenovirus reactivation (n=7). No patient died of infectious complications or PT-LPD. 6 patients have died of regimen-related toxicities (n=4), or disease recurrence (n=2) at a median of 160 days (range, 4–208) post-HSCT. Fourteen patients remain alive in remission at a median of 162 days (range, 49–947) post-HSCT. OKT3 depleted PBSC grafts from haploidentical donors depleted of T-celss ex vivo results in favorable outcomes and acceptably low rates of GVHD and infectious complications for children undergoing HSCT from parental donors.

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Impaired Alloantigen Presenting Activity of Cord Blood Nucleated Cells.

Blood ◽

10.1182/blood.v106.11.2203.2203 ◽

2005 ◽

Vol 106 (11) ◽

pp. 2203-2203

Author(s):

Sandeep Chunduri ◽

Dolores Mahmud ◽

Javaneh Abbasian ◽

Damiano Rondelli

Keyword(s):

T Cells ◽

Stem Cell ◽

T Cell ◽

Cord Blood ◽

Mononuclear Cells ◽

Ex Vivo ◽

Solid Organ Transplantation ◽

T Cell Response ◽

Solid Organ ◽

Cd34 Cells

Abstract Transplantation of HLA-mismatched cord blood (CB) nucleated cells has limited risk of severe acute graft-versus-host disease and graft rejection. This may depend on naïve T cells not yet exposed to many antigens and on immature antigen-presenting cells (APC) not delivering appropriate signals to allogeneic T cells. In order to test the APC activity of human circulating CB cells in-vitro, we initially used irradiated CB mononuclear cells (MNC) or immunomagnetically selected CD34+ cells, CD133+ cells, or CD14+ monocytes to stimulate the proliferative response of incompatible blood T cells in mixed leukocyte culture (MLC). CB MNC failed to induce allogeneic T cell proliferation, while CD34+ and CD133+ progenitors or CD14+ monocytes induced potent T cell alloresponses. Nevertheless, since allogeneic T cell response was not restored after depletion of CD3+ cells in the CB, nor the add-back of irradiated CB MNC to CD34+ or CD14+ stimulators inhibited allo-T cells, a direct suppressive effect of CB MNC was excluded. Allogeneic peripheral blood cytotoxic T-lymphocyte (CTL) responses were not induced after 7 days of stimulation with irradiated CB MNC, although after 4 weekly rechallenges with CB MNC, on average a 23% lysis of antigen-specific CB PHA-blasts was observed at the highest effector:target ratio (50:1). To test the tolerogenic potential of CB MNC, T cells initially exposed to CB MNC were rechallenged in secondary MLC with CB MNC, or CD34+ cells, or monocyte-derived dendritic cells (Mo-DC) generated in liquid culture with GM-CSF and IL-4. Allogeneic T cells were still unresponsive upon rechallenge with CB MNC, but proliferated upon 3 days of restimulation with CD34+ cells or Mo-DC from the same CB. Surprisingly, the supernatant of these latter MLCs did inhibit completely a 3rd party MLC. Instead, the supernatant of blood T cells that had been activated by CB CD34+ cells or Mo-DC both in primary and secondary MLC did not. These results show an impaired allo-APC activity of CB MNC but not CB CD34+ cells, and suggest that T cells releasing immunosuppressive cytokines may be activated by CB MNC and then expanded by a second more potent stimulation with professional APC. This hypothesis could explain the sustained engraftment of HLA-mismatched CB stem cell transplants in humans. Based on these results, the in-vivo or ex-vivo downregulation of T cell alloreactivity induced by CB MNC will be tested in experimental models of stem cell, as well as solid organ transplantation.

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Patients (Pts) Surviving Haploidentical Stem Cell Transplantation (SCT) after Ex Vivo Costimulatory Blockade To Induce Anergy Experience Few Long-Term Complications.

Blood ◽

10.1182/blood.v106.11.599.599 ◽

2005 ◽

Vol 106 (11) ◽

pp. 599-599 ◽

Cited By ~ 3

Author(s):

Eva C. Guinan ◽

John G. Gribben ◽

Lisa L. Brennan ◽

Lee M. Nadler

Keyword(s):

T Cells ◽

Stem Cell ◽

T Cell ◽

Ex Vivo ◽

Chronic Gvhd ◽

T Cell Response ◽

T Cell Repertoire ◽

Cell Repertoire ◽

Costimulatory Blockade ◽

Cell Counts

Abstract Poor and delayed immune reconstitution remains a major stumbling block to successful SCT especially when alternative donors are used. Strategies to selectively remove or inactivate alloreactive cells while leaving the other donor T cell repertoire intact might address this problem. A functional T cell response requires an antigen (Ag)-specific MHC-restricted signal (signal 1) to the T cell receptor (TCR) by an Ag presenting cell (APC) as well as a second, Ag independent costimulatory signal (signal 2) provided in large part by B7 family members on APC to CD28 on T cells. Without signal 2, T cells develop tolerance to the specific Ag. Costimulation can be blocked by either CTLA4-Ig, a fusion of Ig with human CTLA4 (the T cell high affinity B7 ligand) or a combination of humanized IgG2 isotype mutated monoclonal antibodies to the APC molecules B7-1 and B7-2. In 2 pilot studies of patients (pts) undergoing haploidentical SCT, donor T cell replete BM was incubated ex vivo with recipient irradiated peripheral blood mononuclear cells with CTLA4-Ig (pilot 1) or anti-B7-1+anti-B7-2 (pilot 2) to induce alloAg specific tolerance. 19 pts age 7 mos-50 yrs (median 15 yrs) were enrolled on pilot 1 and 5 aged 4–12 (median 6) on pilot 2. 3 pts had congenital BM failure. 21 pts with malignancy, ALL (11), AML(7), NHL(2), MDS(1), were >CR1and 14/21 had progressive disease (PD). Pts received TBI based ablative conditioning. Pts received a median of 3.3x106/kg CD34+ cells (0.5–12.3) containing a median of 2.8x 107/kg CD3+ (0.7–6.8), 1.6x 107/kg CD4+ (0.4–4.1), and 1x107/kg CD8+ (0.2–3.7) T cells. One pt got additional anergized cells for slow recovery and engrafted fully. One AML pt had autologous persistence and graft failure (GF). Evaluable pts engrafted at median 21 d (range, 13–29) with full donor chimerism. Of the 21 evaluable pts, 9 (43%) had findings consistent with acute GVHD graded B (n=4), C (n=4) and D (n=1) despite inconsistent pathology. GVHD symptoms were largely isolated to the GI tract and resolved with observation or moderate steroids. No death was attributable to GVHD. 11 pts died early of a combination of bacterial or fungal infection and/or regimen-related toxicity at a median of 35 d (8–159). Of the remaining 13 pts, the GF pt died after 2nd SCT elsewhere, 1 pt had sudden death d 176 at home and 2 pts with extramedullary AML died d 60 and 149 with PD. One T-ALL pt died of late PD d 1758. All BM failure and 3/14 transplanted with PD survive. All 8 survivors (8/19 < 23 yrs) have 100% performance status at a median of 2423 d (1580–2875). None take medications or have chronic GVHD. 3 pts became CMV Ag + by d 100, (1 was transplanted with CMV), and responded to anti-viral therapy. Unlike many reported approaches to haploidentical SCT, aside from several CVL associated bacteremias, there have been no admissions for opportunistic infection and no late viral infections. All pts have good T cell counts, respond to vaccines and specific Ags and have good immunoglobulin levels. Costimulatory blockade, a method of limiting alloreactivity which leaves the remaining T cell repertoire intact, holds out promise as a method of overcoming alloreactivity while better preserving donor immune function and preserving anti-tumor activity. A new study combining costimulatory blockade and megadose stem cell SCT has been initiated.

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