Abstract: Allogeneic stem cell transplantation would benefit from re-engineering care towards an integrated eHealth-facilitated care model. With this paper we aim to: ( 1) describe the development of an integrated care model (ICM) in allogeneic S te M -cell-transplantat I on faci L itated by e Health (SMILe) by combining implementation, behavioral, and computer science methods (e.g., contextual analysis, Behavior Change Wheel, and user-centered design combined with agile software development); and (2) describe that model’s characteristics and its application in clinical practice. Methods The SMILe intervention’s development consisted of four steps, with implementation science methods informing each: (1) planning its set-up within a theoretical foundation; (2) using behavioral science methods to develop the content; (3) choosing and developing its delivery method (human/technology) using behavioral and computer science methods; and (4) describing its characteristics and application in clinical practice. Results The SMILe intervention is embedded within the eHealth enhanced Chronic Care Model, entailing four self-management intervention modules, targeting monitoring and follow-up of important medical and symptom-related parameters, infection prevention, medication adherence, and physical activity. Interventions are delivered partly face-to-face by a care coordinator embedded within the transplant team, and partly via the SMILeApp that connects patients to the transplant team, who can monitor and rapidly respond to any relevant changes within 1 year post-transplant. Conclusion This paper provides stepwise guidance on how implementation, behavioral, and computer science methods can be used to develop interventions aiming to improve care for stem cell transplant patients in real-world clinical settings. This new care model is currently being tested in a hybrid I effectiveness-implementation trial.

Abstract: CD4+CD25+ Regulatory T cells (Treg) reduce the incidence and severity of acute graft-versus-host disease (GvHD) in murine models of allogeneic bone marrow transplantation (BMT) when given at the time of transplantation at a 1:1 ratio with donor effector T cells (Tcon). In our previous study with Treg trafficking, bioluminescene imaging (BLI) indicated a persistence of signal consistent with a prolonged survival of Treg in vivo following allogeneic BMT. In the current study, we evaluated the duration of Treg suppression and the impact of Treg on evolving and established GvHD. Lethally irradiated Balb/c (H2d) hosts received 5x106 T-cell depleted bone marrow (TCD-BM) cells from wild-type FVB mice (H2q) on day 0. On day 2, 3x106 splenocytes, or 1x106 purified CD4+/CD8+ T cells (Tcon) from luciferase+ transgenic mice (FVB) were infused to induce GvHD. Treg, purified from wt-FVB mice, in a 1:1 dose ratio with Tcon, were infused either on day 0, 2, 9, or 23 post-transplantation. Bioluminescence imaging was used to localize and quantitate the proliferation of Tcon in the absence or presence of Treg. Signal intensity, measured by photons/second/mouse, was significantly decreased in animals which received Treg at day 0, 2, or 9 (p-value & lt; 0.05). More importantly, the greatest reduction in signal intensity occurred when Treg were given prior to the induction of GvHD by Tcon. This reduction was associated with a significantly lower clinical score for GvHD. Studies in which Treg are given up to 10 days prior to the addition of Tcon show similar findings. At day 23, when clinical GvHD was fully established in mice which received Tcon, the addition of Treg did not alter the increasing BLI signal level or the clinical course such that all animals died of GvHD (p-value=0.38). Lymphoid reconstitution was not affected by the addition of Treg prior to the induction of GvHD. In dose titration studies whereby Treg are given two days prior to the induction of GvHD, a 10-fold dose reduction in Treg was sufficient to significantly reduce Tcon proliferation and suppress clinical GvHD. We next assessed the duration of Treg suppressive effect by inducing GvHD on day 7, 14, 19 with luc+ Tcon following the infusion of Treg on day 0 of allogeneic BMT. Treg provided protection from the Tcon challenge at all 3 time points, leading to improved survival (p-value & lt; 0.05). We conclude that Treg provide prolonged protection due to their ability to proliferate in vivo in an allogeneic setting. The capacity of Treg to proliferate in vivo permits a significant reduction in the number of Treg needed for adoptive transfer to induce a clinical response, a practical finding given the rarity of Treg. In addition, we conclude that Treg suppress the early proliferation of Tcon, allowing them to prevent and control evolving but not established GvHD.

Abstract: CD4+CD25+ regulatory T (Treg) cells control immunologic tolerance and antitumor immune responses. Therefore, in vivo modification of Treg function by immunosuppressant drugs has broad implications for transplantation biology, autoimmunity, and vaccination strategies. In vivo bioluminescence imaging demonstrated reduced early proliferation of donor-derived luciferase-labeled conventional T cells in animals treated with Treg cells after major histocompatibility complex mismatch bone marrow transplantation. Combining Treg cells with cyclosporine A (CSA), but not rapamycin (RAPA) or mycophenolate mofetil (MMF), suppressed Treg function assessed by increased T-cell proliferation, graft-versus-host disease (GVHD) severity, and reduced survival. Expansion of Treg and FoxP3 expression within this population was lowest in conjunction with CSA, suggesting that calcineurin-dependent interleukin 2 (IL-2) production is critically required for Treg cells in vivo. The functional defect of Treg cells after CSA exposure could be reversed by exogenous IL-2. Further, the Treg plus RAPA combination preserved graft-versus-tumor (GVT) effector function against leukemia cells. Our data indicate that RAPA and MMF rather than CSA preserve function of Treg cells in pathologic immune responses such as GVHD without weakening the GVT effect. (Blood. 2006;108:390-399)

Abstract: CD4+CD25+ regulatory T cells (Tregs) suppress immune responses to alloantigens. The in vivo circulation and tissue localization of Tregs during an adaptive immune response remain unclear. We noninvasively tracked luciferase-expressing Tregs over time in an allogeneic bone marrow transplant model and demonstrated colocalization with effector T cells and initial expansion in secondary lymphoid organs before migration into inflamed tissues. Inflammation induced by irradiation and the allogeneic setting provided crucial stimuli for early Treg expansion and migration, leading to parallel reduction of effector T-cell proliferation in lymphoid organs and peripheral tissues. Treg transplants conferred long-term protection from systemic inflammatory challenge consistent with Treg in vivo survival. Suppression occurred during multiple phases of inflammation, but is optimal in the initial phase, providing protection from graft-versus-host disease while maintaining the graft-versus-tumor effect even at physiologic doses of Tregs due to their in vivo expansion, hence overcoming a major barrier to potential clinical applications of Tregs given their rarity.

Abstract: Relapse after allogeneic hematopoietic stem cell transplantation (HSCT) remains an unmet medical need. The ETCTN 9204 study evaluated in 71 study subjects if immune checkpoint blockade with anti-CTLA-4 (Ipilimumab (Ipi), n = 43) or anti-PD-1 (Nivolumab (Nivo), n = 28) antibodies could stimulate graft-versus-leukemia (GvL) responses in this setting. We focused mainly on patients (pts) with relapsed AML/MDS, which constituted the majority of pts (n = 38; 54%). Ipi induced both long-term complete remissions (CR; n = 3) and transient CRs (TR; n = 3), while Nivo did not generate any CRs, but 4 patients demonstrated partial remissions (PR). To define the molecular features associated with response to Ipi, we performed bulk transcriptomic analyses of formalin-fixed paraffin-embedded biopsies of sites of AML/MDS involvement (n = 35) collected before and after Ipi treatment from 13 pts. Our analysis of matched pre- and post-Ipi samples of patients with CRs identified 50 differentially expressed genes. By gene ontology analysis, these were enriched for signatures of 'lymphocyte activation' and 'antigen-receptor signaling'. Principal component analysis using these genes separated post-Ipi CR samples as a distinct cluster, transcriptionally apart from pre-Ipi CR samples and from non-responder (NR, n = 15) pre and post-Ipi samples. Of note, post-Ipi CR samples were similar to both pre- and post-Ipi TR samples as well as samples from GvHD/toxicity biopsies (n = 9). Consistent with these findings, we detected increased CD8+ T cell abundance post-Ipi in CR but not NR samples with CIBERSORTx (pre vs post, median score 0.043 vs. 0.56, p & lt; 0.01). Likewise, reconstruction of T cell receptor (TCR) CDR3 sequences using the tool TRUST showed an increase in TCR clonotypes per million reads post-Ipi in CR samples (pre vs post, median 0.33 vs. 1.65, p & lt; 0.05). In sum, response to CTLA-4 blockade is characterized by transcriptional evidence of T cell infiltration and activation within the tumor microenvironment, with similar gene programs observed in the setting of GvHD. To determine if the changes within tissue sites following Ipi are also observed in peripheral blood (PB), we analyzed the immunophenotype and TCR repertoire of T cells from serially collected PB samples from pts with AML/MDS (n = 14) or non-myeloid malignancy (n = 6). In responders and non-responders, exposure to Ipi was associated with decreased naïve, increased effector memory, and increased expression of HLA-DR on central memory T cells (p & lt; 0.05), consistent with T cell differentiation and activation. From 9 of 14 AML/MDS pts (CR = 4, NR = 5), bulk TCR sequencing before and after 1 cycle of Ipi yielded 572,017 PB TCR sequences. Only 776 clonotypes demonstrated significant change in frequency, and these TCRs were detected in greater proportion among responders (613/776 versus NR 163/776, p & lt; 0.01). Thus, Ipi alters the differentiation states of circulating T cells irrespective of response and leads to higher TCR repertoire turnover in CR patients. Of the AML patients achieving PR following Nivo, we also observed transcriptional evidence of CD8+ T cell infiltration in one patient. This signature, however, was not detected in a second such patient. In a separate instance, we had the opportunity to dissect the molecular features of a partial response in a patient with JAK2V617F+ secondary AML following Nivo through single-cell RNA and ATAC-sequencing (scRNA-seq and scATAC-seq, 10x Genomics) of PB mononuclear cells collected serially across 6 timepoints. In total, we analyzed the transcriptomes and chromatin accessibility data from of 27,777 and 28,713 individual cells, respectively. At time of response, non-exhausted CD4+ T cells expanded while both exhausted CD8+ T cells and a malignant subpopulation with increased expression of PD-L1 and features of megakaryocytic differentiation preferentially contracted. The subsequent expansion of a PD-L1- malignant population at progression suggests that decreased leukemic PD-L1 expression was associated with relapse. Altogether, these data highlight the molecular and cellular features of successful reinvigoration of GvL using CTLA-4 blockade, from increased local T cell infiltration and activation in the leukemic microenvironment to peripheral T cell turnover. In addition, the selection of therapy-resistant subclones after PD-1 blockade underscores the need for further high-resolution studies of GvL responses. Disclosures Zeiser: Novartis: Honoraria; Incyte: Honoraria; Malinckrodt: Honoraria. Ritz:Rheos Medicines: Consultancy; LifeVault Bio: Consultancy; Infinity Pharmaceuticals: Consultancy; Falcon Therapeutics: Consultancy; Avrobio: Consultancy; Kite Pharma: Research Funding; Talaris Therapeutics: Consultancy; Equillium: Research Funding; Amgen: Research Funding; TScan Therapeutics: Consultancy. Neuberg:Madrigak Pharmaceuticals: Current equity holder in publicly-traded company; Celgene: Research Funding; Pharmacyclics: Research Funding. Soiffer:alexion: Consultancy; Gilead: Consultancy; Be the Match/ National Marrow Donor Program: Membership on an entity's Board of Directors or advisory committees; Rheos Therapeutics: Consultancy; Juno: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy; Mana Therapeutics: Consultancy; Precision Bioscience: Consultancy; VOR Biopharma: Consultancy; Kiadis: Membership on an entity's Board of Directors or advisory committees; Cugene: Consultancy; Celgene: Membership on an entity's Board of Directors or advisory committees. Liu:GV20 Oncotherapy: Consultancy, Membership on an entity's Board of Directors or advisory committees; 3DMed Care: Consultancy; Sanofi: Research Funding; Takeda: Research Funding. Davids:AbbVie: Consultancy; Gilead Sciences: Consultancy; Sunesis: Consultancy; BeiGene: Consultancy; AstraZeneca: Consultancy, Research Funding; Syros Pharmaceuticals: Consultancy; Research to Practice: Honoraria; Pharmacyclics: Consultancy, Research Funding; TG Therapeutics: Consultancy, Research Funding; Verastem: Consultancy, Research Funding; Adaptive Biotechnologies: Consultancy; Janssen: Consultancy; Surface Oncology: Research Funding; Novartis: Consultancy, Research Funding; MEI Pharma: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Eli Lilly: Consultancy; Zentalis: Consultancy; Celgene: Consultancy; Bristol Myers Squibb: Research Funding; Merck: Consultancy; Ascentage Pharma: Consultancy, Research Funding. Wu:Pharmacyclics: Research Funding; BionTech: Current equity holder in publicly-traded company. OffLabel Disclosure: Ipilimumab and Nivolumab were tested in the setting of relapsed hematological malignancies after allogeneic stem cell transplantation.