Axatilimab in Recurrent or Refractory Chronic Graft-versus-Host Disease.

BACKGROUND: Colony-stimulating factor 1 receptor (CSF1R)-dependent monocytes and macrophages are key mediators of chronic graft-versus-host disease (GVHD), a major long-term complication of allogeneic hematopoietic stem-cell transplantation. The CSF1R-blocking antibody axatilimab has shown promising clinical activity in chronic GVHD. METHODS: In this phase 2, multinational, pivotal, randomized study, we evaluated axatilimab at three different doses in patients with recurrent or refractory chronic GVHD. Patients were randomly assigned to receive axatilimab, administered intravenously, at a dose of 0.3 mg per kilogram of body weight every 2 weeks (0.3-mg dose group), at a dose of 1 mg per kilogram every 2 weeks (1-mg dose group), or at a dose of 3 mg per kilogram every 4 weeks (3-mg dose group). The primary end point was overall response (complete or partial response) in the first six cycles; the key secondary end point was a patient-reported decrease in chronic GVHD symptom burden, as assessed by a reduction of more than 5 points on the modified Lee Symptom Scale (range, 0 to 100, with higher scores indicating worse symptoms). The primary end point would be met if the lower bound of the 95% confidence interval exceeded 30%. RESULTS: A total of 241 patients were enrolled (80 patients in the 0.3-mg dose group, 81 in the 1-mg dose group, and 80 in the 3-mg dose group). The primary end point was met in all the groups; an overall response was observed in 74% (95% confidence interval [CI], 63 to 83) of the patients in the 0.3-mg dose group, 67% (95% CI, 55 to 77) of the patients in the 1-mg dose group, and 50% (95% CI, 39 to 61) of the patients in the 3-mg dose group. A reduction of more than 5 points on the modified Lee Symptom Scale was reported in 60%, 69%, and 41% of the patients in the three dose groups, respectively. The most common adverse events were dose-dependent transient laboratory abnormalities related to CSF1R blockade. Adverse events leading to discontinuation of axatilimab occurred in 6% of the patients in the 0.3-mg dose group, 22% in the 1-mg dose group, and 18% in the 3-mg dose group. CONCLUSIONS: Targeting CSF1R-dependent monocytes and macrophages with axatilimab resulted in a high incidence of response among patients with recurrent or refractory chronic GVHD. (Funded by Syndax Pharmaceuticals and Incyte; AGAVE-201 ClinicalTrials.gov number, NCT04710576.).

Axatilimab for Chronic Graft-Versus-Host Disease After Failure of at Least Two Prior Systemic Therapies: Results of a Phase I/II Study.

PURPOSE: Chronic graft-versus-host disease (cGVHD) remains the major cause of late morbidity after allogeneic hematopoietic cell transplantation. Colony-stimulating factor 1 receptor (CSF-1R)-dependent macrophages promote cGVHD fibrosis, and their elimination in preclinical studies ameliorated cGVHD. Axatilimab is a humanized monoclonal antibody that inhibits CSF-1R signaling and restrains macrophage development. PATIENTS AND METHODS: This phase I (phI)/phase II (phII) open-label study (ClinicalTrials.gov identifier: NCT03604692) evaluated safety, tolerability, and efficacy of axatilimab in patients age ≥ 6 years with active cGVHD after ≥ 2 prior systemic therapy lines. Primary objectives in phI were to identify the optimal biologic and recommended phII dose and in phII to evaluate the overall (complete and partial) response rate (ORR) at the start of treatment cycle 7. RESULTS: Forty enrolled patients (17 phI; 23 phII) received at least one axatilimab dose. In phI, a dose of 3 mg/kg given once every 4 weeks met the optimal biologic dose definition. Two dose-limiting toxicities occurred at the 3 mg/kg dose given once every 2 weeks. At least one treatment-related adverse event (TRAE) was observed in 30 patients with grade ≥ 3 TRAEs in eight patients, the majority known on-target effects of CSF-1R inhibition. No cytomegalovirus reactivations occurred. With the 50% ORR at cycle 7 day 1, the phII cohort met the primary efficacy end point. Furthermore, the ORR in the first six cycles, an end point supporting regulatory approvals, was 82%. Responses were seen in all affected organs regardless of prior therapy. Fifty-eight percent of patients reported significant improvement in cGVHD-related symptoms using the Lee Symptom Scale. On-target activity of axatilimab was suggested by the decrease in skin CSF-1R-expressing macrophages. CONCLUSION: Targeting profibrotic macrophages with axatilimab is a therapeutically promising novel strategy with a favorable safety profile for refractory cGVHD.

Immune dysfunction signatures predict outcomes and define checkpoint blockade-unresponsive microenvironments in acute myeloid leukemia.

BackgroundImmune exhaustion and senescence are dominant dysfunctional states of effector T cells and major hurdles for the success of cancer immunotherapy. In the current study, we characterized how acute myeloid leukemia (AML) promotes the generation of senescent-like CD8+ T cells and whether they have prognostic relevance.METHODSWe analyzed NanoString, bulk RNA-Seq and single-cell RNA-Seq data from independent clinical cohorts comprising 1,896 patients treated with chemotherapy and/or immune checkpoint blockade (ICB).ResultsWe show that senescent-like bone marrow CD8+ T cells were impaired in killing autologous AML blasts and that their proportion negatively correlated with overall survival (OS). We defined what we believe to be new immune effector dysfunction (IED) signatures using 2 gene expression profiling platforms and reported that IED scores correlated with adverse-risk molecular lesions, stemness, and poor outcomes; these scores were a more powerful predictor of OS than 2017-ELN risk or leukemia stem cell (LSC17) scores. IED expression signatures also identified an ICB-unresponsive tumor microenvironment and predicted significantly shorter OS.ConclusionThe IED scores provided improved AML-risk stratification and could facilitate the delivery of personalized immunotherapies to patients who are most likely to benefit.TRIAL REGISTRATIONClinicalTrials.gov; NCT02845297.FUNDINGJohn and Lucille van Geest Foundation, Nottingham Trent University's Health & Wellbeing Strategic Research Theme, NIH/NCI P01CA225618, Genentech-imCORE ML40354, Qatar National Research Fund (NPRP8-2297-3-494).

Adoptive transfer of IL-4 reprogrammed Tc17 cells elicits anti-tumour immunity through functional plasticity.

Ability of IL-17-producing CD8+ T cells (Tc17) to transform into cytotoxic anti-tumour effectors makes them a promising candidate for immune effector cell (IEC) therapy. However, key factors regulating Tc17 reprogramming remain poorly defined, hindering translation of Tc17-based IEC use from bench to bedside. We probed the effects of multiple cytokines and underlying signalling pathways on Tc17 cells and identified pivotal role for IL-4 and PI3K/AKT in promoting Tc17 transformation into cytotoxic IFN-γ-producing IECs, an effect dependent on Eomes expression. IL-4 not only triggered Tc17 cytotoxicity, but also induced cell expansion, which significantly improved the antitumour potential of Tc17 cells compared to that of IFN-γ-producing CD8+ T cells (Tc1) in a murine model. Furthermore, IL-4/AKT signalling drove the upregulation of the T-cell receptor-associated transmembrane adaptor 1 (Trat1) in Tc17 cells to promote IL-4-induced T-cell receptor stabilization and Tc17 cytotoxicity. Finally, we proposed a possible procedure to expand human Tc17 from peripheral blood of cancer patients, and confirmed the function of IL-4 in Tc17 reprogramming. Collectively, these results document a novel IL-4/AKT/Eomes/Trat1 axis that promotes expansion and transformation of Tc17 cells into cytotoxic effectors with a therapeutic potential. IL-4 priming of Tc17 cells should be further explored as a cell therapy engineering strategy to generate IECs to augment anti-tumour responses.

Signatures of GVHD and relapse after posttransplant cyclophosphamide revealed by immune profiling and machine learning.

The key immunologic signatures associated with clinical outcomes after posttransplant cyclophosphamide (PTCy)-based HLA-haploidentical (haplo) and HLA-matched bone marrow transplantation (BMT) are largely unknown. To address this gap in knowledge, we used machine learning to decipher clinically relevant signatures from immunophenotypic, proteomic, and clinical data and then examined transcriptome changes in the lymphocyte subsets that predicted major posttransplant outcomes. Kinetics of immune subset reconstitution after day 28 were similar for 70 patients undergoing haplo and 75 patients undergoing HLA-matched BMT. Machine learning based on 35 candidate factors (10 clinical, 18 cellular, and 7 proteomic) revealed that combined elevations in effector CD4+ conventional T cells (Tconv) and CXCL9 at day 28 predicted acute graft-versus-host disease (aGVHD). Furthermore, higher NK cell counts predicted improved overall survival (OS) due to a reduction in both nonrelapse mortality and relapse. Transcriptional and flow-cytometric analyses of recovering lymphocytes in patients with aGVHD identified preserved hallmarks of functional CD4+ regulatory T cells (Tregs) while highlighting a Tconv-driven inflammatory and metabolic axis distinct from that seen with conventional GVHD prophylaxis. Patients developing early relapse displayed a loss of inflammatory gene signatures in NK cells and a transcriptional exhaustion phenotype in CD8+ T cells. Using a multimodality approach, we highlight the utility of systems biology in BMT biomarker discovery and offer a novel understanding of how PTCy influences alloimmune responses. Our work charts future directions for novel therapeutic interventions after these increasingly used GVHD prophylaxis platforms. Specimens collected on NCT0079656226 and NCT0080927627 https://clinicaltrials.gov/.

National Institutes of Health Consensus Development Project on Criteria for Clinical Trials in Chronic Graft-versus-Host Disease: IV. The 2020 Highly morbid forms report.

Chronic graft-versus-host disease (GVHD) can be associated with significant morbidity, in part because of nonreversible fibrosis, which impacts physical functioning (eye, skin, lung manifestations) and mortality (lung, gastrointestinal manifestations). Progress in preventing severe morbidity and mortality associated with chronic GVHD is limited by a complex and incompletely understood disease biology and a lack of prognostic biomarkers. Likewise, treatment advances for highly morbid manifestations remain hindered by the absence of effective organ-specific approaches targeting "irreversible" fibrotic sequelae and difficulties in conducting clinical trials in a heterogeneous disease with small patient numbers. The purpose of this document is to identify current gaps, to outline a roadmap of research goals for highly morbid forms of chronic GVHD including advanced skin sclerosis, fasciitis, lung, ocular and gastrointestinal involvement, and to propose strategies for effective trial design. The working group made the following recommendations: (1) Phenotype chronic GVHD clinically and biologically in future cohorts, to describe the incidence, prognostic factors, mechanisms of organ damage, and clinical evolution of highly morbid conditions including long-term effects in children; (2) Conduct longitudinal multicenter studies with common definitions and research sample collections; (3) Develop new approaches for early identification and treatment of highly morbid forms of chronic GVHD, especially biologically targeted treatments, with a special focus on fibrotic changes; and (4) Establish primary endpoints for clinical trials addressing each highly morbid manifestation in relationship to the time point of intervention (early versus late). Alternative endpoints, such as lack of progression and improvement in physical functioning or quality of life, may be suitable for clinical trials in patients with highly morbid manifestations. Finally, new approaches for objective response assessment and exploration of novel trial designs for small populations are required.

BAFF promotes heightened BCR responsiveness and manifestations of chronic GVHD after allogeneic stem cell transplantation.

Patients with chronic graft-versus-host disease (cGVHD) have increased B cell-activating factor (BAFF) levels, but whether BAFF promotes disease after allogeneic bone marrow transplantation (allo-BMT) remains unknown. In a major histocompatibility complex-mismatched model with cGVHD-like manifestations, we first examined B-lymphopenic µMT allo-BMT recipients and found that increased BAFF levels in cGVHD mice were not merely a reflection of B-cell number. Mice that later developed cGVHD had significantly increased numbers of recipient fibroblastic reticular cells with higher BAFF transcript levels. Increased BAFF production by donor cells also likely contributed to cGVHD, because BAFF transcript in CD4+ T cells from diseased mice and patients was increased. cGVHD manifestations in mice were associated with high BAFF/B-cell ratios and persistence of B-cell receptor (BCR)-activated B cells in peripheral blood and lesional tissue. By employing BAFF transgenic (Tg) mice donor cells, we addressed whether high BAFF contributed to BCR activation in cGVHD. BAFF increased NOTCH2 expression on B cells, augmenting BCR responsiveness to surrogate antigen and NOTCH ligand. BAFF Tg B cells had significantly increased protein levels of the proximal BCR signaling molecule SYK, and high SYK protein was maintained by BAFF after in vitro BCR activation or when alloantigen was present in vivo. Using T cell-depleted (BM only) BAFF Tg donors, we found that BAFF promoted cGVHD manifestations, circulating GL7+ B cells, and alloantibody production. We demonstrate that pathologic production of BAFF promotes an altered B-cell compartment and augments BCR responsiveness. Our findings compel studies of therapeutic targeting of BAFF and BCR pathways in patients with cGVHD.