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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.

Supplemental figures S1-S11

Supplementary patient data, supplementary materials and methods

Supplemental patient tables (1-3) and mass cytometry reagent table (4)

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Purpose: Cutaneous sclerosis occurs in 20% of patients with chronic graft-versus-host disease (GVHD) and can compromise mobility and quality of life.Experimental design: We conducted a prospective, multicenter, randomized, two-arm phase II crossover trial of imatinib (200 mg daily) or rituximab (375 mg/m2 i.v. weekly × 4 doses, repeatable after 3 months) for treatment of cutaneous sclerosis diagnosed within 18 months (NCT01309997). The primary endpoint was significant clinical response (SCR) at 6 months, defined as quantitative improvement in skin sclerosis or joint range of motion. Treatment success was defined as SCR at 6 months without crossover, recurrent malignancy or death. Secondary endpoints included changes of B-cell profiles in blood (BAFF levels and cellular subsets), patient-reported outcomes, and histopathology between responders and nonresponders with each therapy.Results: SCR was observed in 9 of 35 [26%; 95% confidence interval (CI); 13%–43%] participants randomized to imatinib and 10 of 37 (27%; 95% CI, 14%–44%) randomized to rituximab. Six (17%; 95% CI, 7%–34%) patients in the imatinib arm and 5 (14%; 95% CI, 5%–29%) in the rituximab arm had treatment success. Higher percentages of activated B cells (CD27+) were seen at enrollment in rituximab-treated patients who had treatment success (P = 0.01), but not in imatinib-treated patients.Conclusions: These results support the need for more effective therapies for cutaneous sclerosis and suggest that activated B cells define a subgroup of patients with cutaneous sclerosis who are more likely to respond to rituximab. Clin Cancer Res; 22(2); 319–27. ©2015 AACR.

Supplemental Table. Grade 3-5 adverse events possibly, probably or definitely attributed to imatinib or rituximab Supplemental Figure 1. Vienna Skin Score (VSS) (1) Supplemental Figure 2. Photograph Range of Motion Scale - Modified from (2) Supplemental Figure 3. Total numbers of B cells (CD19+ CD3- lymphocytes) was calculated in patients analyzed in Figure 3 who had available absolute lymphocyte counts. Supplemental Figure 4. BAFF levels at enrollment across treatment groups. Plasma soluble BAFF levels were determined in patients who later either experienced treatment success or did not respond to imatinib or rituximab.

Natural killer (NK) cells are a promising alternative to T cells for cancer immunotherapy. Adoptive therapies with allogeneic, cytokine-activated NK cells are being investigated in clinical trials. However, the optimal cytokine support after adoptive transfer to promote NK cell expansion, and persistence remains unclear. Correlative studies from 2 independent clinical trial cohorts treated with major histocompatibility complex-haploidentical NK cell therapy for relapsed/refractory acute myeloid leukemia revealed that cytokine support by systemic interleukin-15 (IL-15; N-803) resulted in reduced clinical activity, compared with IL-2. We hypothesized that the mechanism responsible was IL-15/N-803 promoting recipient CD8 T-cell activation that in turn accelerated donor NK cell rejection. This idea was supported by increased proliferating CD8+ T-cell numbers in patients treated with IL-15/N-803, compared with IL-2. Moreover, mixed lymphocyte reactions showed that IL-15/N-803 enhanced responder CD8 T-cell activation and proliferation, compared with IL-2 alone. Additionally, IL-15/N-803 accelerated the ability of responding T cells to kill stimulator-derived memory-like NK cells, demonstrating that additional IL-15 can hasten donor NK cell elimination. Thus, systemic IL-15 used to support allogeneic cell therapy may paradoxically limit their therapeutic window of opportunity and clinical activity. This study indicates that stimulating patient CD8 T-cell allo-rejection responses may critically limit allogeneic cellular therapy supported with IL-15. This trial was registered at www.clinicaltrials.gov as #NCT03050216 and #NCT01898793.

The discipline of Cardio-Oncology has seen tremendous growth over the past decade. It is devoted to the cardiovascular (CV) care of the cancer patient, especially to the mitigation and management of CV complications or toxicities of cancer therapies, which can have profound implications on prognosis. To that effect, many studies have assessed CV toxicities in patients undergoing various types of cancer therapies; however, direct comparisons have proven difficult due to lack of uniformity in CV toxicity endpoints. Similarly, in clinical practice, there can be substantial differences in the understanding of what constitutes CV toxicity, which can lead to significant variation in patient management and outcomes. This document addresses these issues and provides consensus definitions for the most commonly reported CV toxicities, including cardiomyopathy/heart failure and myocarditis, vascular toxicity, and hypertension, as well as arrhythmias and QTc prolongation. The current document reflects a harmonizing review of the current landscape in CV toxicities and the definitions used to define these. This consensus effort aims to provide a structure for definitions of CV toxicity in the clinic and for future research. It will be important to link the definitions outlined herein to outcomes in clinical practice and CV endpoints in clinical trials. It should facilitate communication across various disciplines to improve clinical outcomes for cancer patients with CV diseases.

Key Points Variation in initial systemic therapy for chronic graft-versus-host disease includes varied prednisone dose and use of nonsteroid agents.Prospective trials are needed to verify efficacy of reduced-dose prednisone or prednisone-free initial therapy approaches., Visual Abstract, Prior clinical trials largely considered prednisone 1 mg/kg per day with or without calcineurin inhibitor as standard initial therapy for chronic graft-versus-host disease (cGVHD), but uncertainty remains regarding the extent of practice variation and whether this affects subsequent outcomes. We assembled a cohort of 745 patients with cGVHD treated with initial systemic immune suppressive (IS) therapy from 3 prior cGVHD Consortium observational studies. Initial therapy was defined as first IS therapy started for cGVHD or prednisone increased to ≥0.4 mg/kg per day from lower doses within 30 days before cGVHD diagnosis to any time afterward. Initial therapies were nonprednisone IS therapies (n = 137, 18%), prednisone alone (n = 411, 55%), or prednisone plus other IS therapy (n = 197, 26%). In multivariate analysis, initial therapy group was not associated with failure-free survival (FFS; a composite of death, relapse, and new IS therapy), overall survival (OS), or nonrelapse mortality (NRM). Among the prednisone-based approaches, steroid dose was 1.25 mg/kg per day (13%). Prednisone dose within the patients treated with steroids was not significantly associated with FFS, OS, or NRM. No significant interactions were detected between overall cGVHD severity and either initial therapy group or prednisone dose for the outcomes of FFS, OS, or NRM. These observational data document heterogeneity in more contemporary cGVHD initial treatment practices, including prednisone dose and use of nonsteroid approaches. This variation was not associated with FFS, OS, or NRM. Prospective trials are needed to verify efficacy of reduced-dose prednisone or prednisone-free initial therapy approaches.

PURPOSE Standard cytotoxic induction chemotherapy for acute myeloid leukemia (AML) results in prolonged neutropenia and risk of infection. Romyelocel-L is a universal, allogeneic myeloid progenitor cell product being studied to reduce infection during induction chemotherapy. PATIENTS AND METHODS One hundred sixty-three patients with de novo AML (age ≥ 55 years) receiving induction chemotherapy were randomly assigned on day 0 (d0), of whom 120 were evaluable. Subjects received either romyelocel-L infusion on d9 with granulocyte colony-stimulating factor (G-CSF) starting daily d14 (treatment group) or G-CSF daily alone on d14 (control) until absolute neutrophil count recovery to 500/µL. End points included days in febrile episode, microbiologically defined infections, clinically diagnosed infection, and days in hospital. RESULTS Mean days in febrile episode was shorter in the treatment arm from d15 through d28 (2.36 v 3.90; P = .02). Similarly, a trend toward decreased microbiologically defined infections and clinically diagnosed infection in the treatment arm was observed from d9 to d28 (35.6% v 47.5%; P = .09), reaching a statistically significant difference from d15 to d28 (6.8% v 27.9%; P = .002). Because of this, antibacterial or antifungal use for treatment of an infection was significantly less in the treatment group (d9-d28: 44.1% v 63.9%; P = .01). Significantly fewer patients in the treatment arm received empiric antifungals from d9 tod28 (42.4% v 63.9%; P = .02) and d15-d28 (42.4% v 62.3%; P = .02). Patients in the treatment arm also had 3.2 fewer hospital days compared with control (25.5 v 28.7; P = .001). Remission rates and days to absolute neutrophil count recovery were similar in the two groups. No patients in the romyelocel-L plus G-CSF group died because of infection compared with two patients in the control arm. No graft-versus-host disease was observed. CONCLUSION Subjects receiving romyelocel-L showed a decreased incidence of infections, antimicrobial use, and hospitalization, suggesting that romyelocel-L may provide a new option to reduce infections in patients with AML undergoing induction therapy.

The primary two-dose SARS-CoV-2 mRNA vaccine series are strongly immunogenic in humans, but the emergence of highly infectious variants necessitated additional doses of these vaccines and the development of new variant-derived ones1–4. SARS-CoV-2 booster immunizations in humans primarily recruit pre-existing memory B cells (MBCs)5–9. It remains unclear, however, whether the additional doses induce germinal centre (GC) reactions where reengaged B cells can further mature and whether variant-derived vaccines can elicit responses to novel epitopes specific to such variants. Here, we show that boosting with the original SARS- CoV-2 spike vaccine (mRNA-1273) or a B.1.351/B.1.617.2 (Beta/Delta) bivalent vaccine (mRNA-1273.213) induces robust spike-specific GC B cell responses in humans. The GC response persisted for at least eight weeks, leading to significantly more mutated antigen-specific MBC and bone marrow plasma cell compartments. Interrogation of MBC-derived spike-binding monoclonal antibodies (mAbs) isolated from individuals boosted with either mRNA-1273, mRNA-1273.213, or a monovalent Omicron BA.1-based vaccine (mRNA-1273.529) revealed a striking imprinting effect by the primary vaccination series, with all mAbs (n=769) recognizing the original SARS-CoV-2 spike protein. Nonetheless, using a more targeted approach, we isolated mAbs that recognized the spike protein of the SARS-CoV-2 Omicron (BA.1) but not the original SARS-CoV-2 spike from the mRNA-1273.529 boosted individuals. The latter mAbs were less mutated and recognized novel epitopes within the spike protein, suggesting a naïve B cell origin. Thus, SARS-CoV-2 boosting in humans induce robust GC B cell responses, and immunization with an antigenically distant spike can overcome the antigenic imprinting by the primary vaccination series.

Introduction: Offering the optimal frontline treatment to a patient with acute myeloid leukemia (AML) requires trading off expected benefit and risk. Typical standard of care intensive induction chemotherapy (e.g., cytarabine plus idarubicin (7+3)) results in high clinical response rates. However, many patients receive a less intensive regimen (e.g., venetoclax plus decitabine (VenDec)) because their individual toxicity risk is high based on lack of medical fitness. Predicting an individual patient’s clinical response prior to treatment has the potential to increase the benefit/risk ratio (therapeutic index) for some patients and optimize their treatment selection. Here, we demonstrate the ability of an automated high-throughput, multi-color flow cytometry predictive precision medicine platform (PPMP) to predict response to 7+3 or VenDec. Methods: To assess correlation between PPMP-predicted and actual clinical response to 7+3 or VenDec in clinical trial NCT04263181, pre-induction blood samples were collected from 31 patients of which 18 received 7+3 (all newly diagnosed (ND) AML) and 13 VenDec (7 ND AML, 5 secondary AML, 1 MDS). We measured drug effects on leukemic blasts by applying a cutoff at the total blast count that optimizes separation between predicted responders and non-responders (“conventional approach”) or by a machine learning (ML) approach considering multiple cell populations. For the former approach, training sets represented 13 patients for 7+3 and 8 for VenDec. Both 7+3 and VenDec models were validated with 5 patients. For the ML approach, the model was trained on all 13 VenDec patients and monitored using leave-one-out cross-validation. Results: For the conventional approach, predicted and true clinical responses were highly correlated for 7+3 (AUC = 0.91) and VenDec (AUC = 0.81), with 100% precision (positive predictive values (PPV)) for both, i.e., all predicted responders were true clinical responders. Some true clinical responders were not identified (negative predictive value (NPV) = 67% for 7+3 and 57% for VenDec), resulting in an accuracy of 94% (7+3) and 77% (VenDec). To maximize NPV and accuracy for predicting VenDec clinical outcomes, we applied a novel ML-based algorithm to integrate the behavior of malignant and non-malignant cell populations, yielding a model with 100% accuracy (100% PPV and NPV). Additional outcome data, including overall survival, are under evaluation. Summary: Total blast-based predictions yielded accuracies of 94% for 7+3 and 77% for VenDec. An ML algorithm for VenDec considering additional cell populations increased the accuracy to 100%. Further studies will expand patient numbers. We plan to use this platform to inform our frontline decision making with the goal to maximize the therapeutic benefit/risk ratio and ensure that the most appropriate frontline therapy is used for each individual patient. Citation Format: Meagan A. Jacoby, John S. Welch, Peter Westervelt, Matthew Christopher, Geoffrey L. Uy, Ravi Vij, Keith E. Stockerl-Goldstein, Brad S. Kahl, Iskra Pusic, John F. DiPersio, Mark A. Schroeder, Miriam Y. Kim, Todd A. Fehniger, Armin Ghobadi, Christine J. Gu, Wade Anderson, Kathryn Vanderlaag, Kamran Ali, Camille Pataki, Markus D. Lacher. Predictive precision medicine platform accurately predicts individual patient response to AML treatments to maximize outcomes. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4342.

Natural killer (NK) cells are an emerging cancer cellular therapy and potent mediators of antitumor immunity. Cytokine-induced memory-like (ML) NK cellular therapy is safe and induces remissions in patients with acute myeloid leukemia (AML). However, the dynamic changes in phenotype that occur after NK-cell transfer that affect patient outcomes remain unclear. Here, we report comprehensive multidimensional correlates from ML NK cell–treated patients with AML using mass cytometry. These data identify a unique in vivo differentiated ML NK–cell phenotype distinct from conventional NK cells. Moreover, the inhibitory receptor NKG2A is a dominant, transcriptionally induced checkpoint important for ML, but not conventional NK-cell responses to cancer. The frequency of CD8α+ donor NK cells is negatively associated with AML patient outcomes after ML NK therapy. Thus, elucidating the multidimensional dynamics of donor ML NK cells in vivo revealed critical factors important for clinical response, and new avenues to enhance NK-cell therapeutics. Significance: Mass cytometry reveals an in vivo memory-like NK-cell phenotype, where NKG2A is a dominant checkpoint, and CD8α is associated with treatment failure after ML NK–cell therapy. These findings identify multiple avenues for optimizing ML NK–cell immunotherapy for cancer and define mechanisms important for ML NK–cell function. This article is highlighted in the In This Issue feature, p. 1775

Chronic myeloid leukemia (CML) is defined by the presence of Philadelphia chromosome (Ph) which results from a reciprocal translocation between chromosomes 9 and 22 [t(9;22] that gives rise to aBCR-ABL1fusion gene. CML occurs in 3 different phases (chronic, accelerated, and blast phase) and is usually diagnosed in the chronic phase. Tyrosine kinase inhibitor therapy is a highly effective first-line treatment option for all patients with newly diagnosed chronic phase CML. This manuscript discusses the recommendations outlined in the NCCN Guidelines for the diagnosis and management of patients with chronic phase CML.

New therapeutic approaches are needed to improve outcomes of patients with advanced chronic graft vs. host disease (GVHD). Pre-clinical and clinical data suggest proteasome inhibition may modulate GVHD. In a phase II, single-arm, multi-center trial conducted by the Chronic GVHD Consortium, we examined the efficacy of ixazomib in advanced chronic GVHD treatment. Ixazomib was given as a 4 mg oral dose weekly on days 1, 8, and 15 of a 28-day cycle for up to 6 total cycles. An amendment permitted additional cycles beyond 6 for those with responsive chronic GVHD. The primary endpoint was 6 month treatment failure, a composite endpoint including death, relapse, and requirement for an additional line of systemic immune suppressive (IS) therapy, compared with a historical 6 month treatment failure rate of 44% based on 312 patients treated with secondary therapy. Key eligibility criteria included age ≥ 18, NIH Consensus defined chronic GVHD, failure of at least one prior line of systemic IS therapy, and adequate hematologic parameters, hepatic, and renal function. A total of 50 subjects were enrolled at 6 institutions. Median age was 58 years. Median time from transplant to enrollment was 3.6 years (IQR 2.6-5.5), and from chronic GVHD onset to enrollment 2.8 years (IQR 1.5-4.3). Chronic GVHD was NIH moderate (16%) or severe (84%), predominantly classic (80% vs. overlap 20%), with 52% having 4 or more involved organs. Patients were heavily pretreated with 39 (78%) having 3 or more prior lines of systemic therapy for chronic GVHD. Of the 50 treated subjects, 26 completed all 6 months of planned therapy. Dose reductions most commonly occurred for thrombocytopenia, fatigue, diarrhea, and infection. SAEs occurred in 38% of subjects, and 5 deaths occurred in study participants (2 deemed possibly related to ixazomib). The 6 month treatment failure rate was significantly improved vs. the historical benchmark (28% vs. 44%, p=0.01), Figure 1. No patient, transplant, or chronic GVHD variables were significantly associated with 6 month treatment failure. NIH response rates at 3, 6, and 12 months are presented in Figure 2; the ORR was 34% (17/50) at 6 months. Overall survival at 6 and 12 months was 92% and 90%. No subjects completely discontinued IS by 12 months. Ixazomib met the primary endpoint of low treatment failure at 6 months in the setting of advanced chronic GVHD. At 6 months the ORR rate was 34% and 50% remained on ixazomib suggesting the low treatment failure rate was in part due to prevention of progressive disease that would have required additional treatment. Randomized studies are warranted.

Implementation of the 2014 National Institutes of Health (NIH) response algorithm for joint/fascia graft-versus-host disease (GVHD) has identified real-world limits to its application. To refine the 2014 NIH response algorithm, we analyzed multicenter prospective observational data from the Chronic GVHD Consortium. The training cohort included 209 patients and the replication cohort included 191 patients with joint/fascia involvement during their course of chronic GVHD. Linear mixed models with random patient effect were used to evaluate correlations between response categories and clinician- or patient-perceived changes in joint status as an anchor of response. Analysis of the training cohort showed that a 2-point change in total photographic range of motion (P-ROM) score was clinically meaningful. The results also suggested that a change from 0 to 1 on the NIH joint/fascia score should not be considered as worsening and suggested that both the NIH joint/fascia score and total P-ROM score, but not individual P-ROM scores, should be used for response assessment. On the basis of these results, we developed an evidence-based refined algorithm, the utility of which was examined in an independent replication cohort. Using the refined algorithm, ∼40% of responses were reclassified, largely mitigating most divergent responses among individual joints and changes from 0 to 1 on the NIH joint/fascia score. The refined algorithm showed robust point estimates and tighter 95% confidence intervals associated with clinician- or patient-perceived changes, compared with the 2014 NIH algorithm. The refined algorithm provides a superior, evidence-based method for measuring therapeutic response in joint/fascia chronic GVHD.

Introduction: Haploidentical peripheral blood allogeneic hematopoietic cell transplantation (PB haplo-HCT) can be complicated by graft-versus-host disease (GVHD) and cytokine release syndrome (CRS). Acute GVHD rates are higher with PB grafts compared with bone marrow, affecting 35-45% of patients and outcomes are poor in steroid refractory cases. Severe CRS occurs in 10-15% of patients receiving PB haplo-HCT and is associated with high non-relapse mortality and dismal one year overall survival between 25-30%. As interferon-γ and IL-6 are important mediators in both acute GVHD and CRS, we hypothesized that JAK1 inhibition with itacitinib could prevent these toxicities without impairing engraftment. Here we report the clinical outcomes from our pilot study of itacitinib with haplo-HCT (NCT03755414). Methods: Patients with AML, ALL, or NHL in remission undergoing PB haplo-HCT were treated with itacitinib 200 mg/day on days -3 through +100, followed by a taper. Myeloablative and reduced intensity conditioning were allowed. GVHD prophylaxis was tacrolimus, mycophenolate mofetil, and post-transplant cyclophosphamide. Primary outcomes were incidence of primary graft failure and incidence of grade III-IV acute GVHD. Secondary outcomes included incidence and severity of CRS (graded by Lee criteria). Peripheral blood and serum samples were banked prior to conditioning and on days -1, 1, 3, 7, 14, 28, 60, 100, end of treatment, and time of diagnosis of acute GVHD. Matched control samples were collected from patients undergoing haplo-HCT off clinical trials. Correlative studies include flow cytometry (FACS) with five 28-color panels for cellular subsets, mass cytometry (CyTOF) with 40-colors for intracellular signaling events, single cell RNA sequencing, and serum cytokine and chemokine measurements. Results: Twenty of a planned 20 patients completed enrollment and underwent haplo-HCT between 11/2019 and 3/2021. Median age at transplant was 49 (21-74). Diagnoses were AML (13), ALL (5) and NHL (2). Median follow up is 319 days, with 18/20 beyond 180 days. There were no cases of engraftment failure with short median times to neutrophil (14 days, range 12-20) and platelet (14 days, range 7-54) engraftment (historical 16 and 25 days, respectively). There were no cases of grade III-IV acute GVHD. The incidence of grade II acute GVHD on day 100 was 15%. Two patients developed grade I-II skin acute GVHD during itacitinib taper and responded to resumption of a higher dose. There were no cases of extensive chronic GVHD. There were no cases of severe CRS (historical rate 17%), with 90% of patients having grade 1 CRS and 10% having no CRS. Furthermore, no anti-IL6R or steroid therapy was used. Overall survival at day 180 was 90% (95% CI 75-100%) by Kaplan-Meier estimate. Incidence of relapse at 180 days was 5.5% (95% CI 0-15.6%). Refined GVHD and relapse-free survival at 180 days was 83% (95% CI 68-100%). All patients had full donor engraftment and >95% chimerism at day 100. FACS and CyTOF have been performed and analyzed for the day 28 time point from 14 patients and four controls. Flow cytometry revealed no difference in cell subset numbers between controls and patient samples. CyTOF revealed differences in intracellular signaling molecules between itacitinib and control patients - including higher Ki-67, pNF-κB, and Caspase3 in controls. Phospho-Stat1 and pStat3 were lower CD4 T subsets. FACS and CyTOF at remaining time points, single cell RNA sequencing, and serum cytokine and chemokine measurements are underway and will be presented at the ASH 2021 meeting. Conclusions: Itacitinib with PB haplo-HCT was safe with no engraftment failure and prompt engraftment. Rates of acute and chronic GVHD were low, without increased risk of relapse or transplant related mortality. Severe CRS was not seen in this trial, and no anti-IL6 or steroid therapy was used. Flow cytometry demonstrated comparable immune reconstitution in terms of cell lineage and number between treated patients and controls. Mass cytometry revealed lower Ki-67, pNF-κB, and caspase3 levels, among other markers, which suggest lower immune cell activity, proliferation, and apoptosis. An extension cohort of 20 additional patients is enrolling. Multi-platform correlative studies are underway, comparing samples from haplo-HCT patients treated with and without itacitinib. Figure 1 Figure 1. Disclosures Uy: Astellas: Honoraria, Speakers Bureau; Novartis: Consultancy; Agios: Consultancy; Jazz: Consultancy; Genentech: Consultancy; AbbVie: Consultancy; GlaxoSmithKline: Consultancy; Macrogenics: Research Funding. Ghobadi: Atara: Consultancy; Amgen: Consultancy, Research Funding; Wugen: Consultancy; Celgene: Consultancy; Kite, a Gilead Company: Consultancy, Honoraria, Research Funding. Jacoby: Abbvie: Research Funding; Jazz: Research Funding. Pusic: Syndax: Other: Advisory Board. Schroeder: Equillium Inc: Honoraria; Janssen: Honoraria; Sanofi Genzyme: Honoraria.

Leukemia stem cells utilize cell adhesion molecules like CXCR4/CXCL12 to home to bone marrow stromal niches where they are maintained in a dormant, protected state. Dociparstat sodium (DSTAT, CX-01) is a low anticoagulant heparin with multiple mechanisms of action, including inhibition of the CXCR4/CXCL12 axis, blocking HMGB1, and binding platelet factor 4 (PF-4). We conducted a pilot study adding DSTAT to azacitidine for patients with AML or MDS unresponsive to or relapsed after prior hypomethylating agent therapy, hypothesizing that DSTAT may improve response rates. Twenty patients were enrolled, with a median of 2 prior lines of therapy and 6 cycles of prior hypomethylating agents. Among fifteen patients evaluable for response, there was 1 complete remission, and 3 marrow complete remissions, for a response rate of 27 % among evaluable patients (20 % overall). Hematologic improvement was observed in 5 additional patients. The median overall survival for all enrolled patients was 205 days (95 % CI 119–302). While cytopenias and infections were common, these were not out of proportion to what would be expected in this population of patients undergoing treatment with azacitidine alone. In summary, this trial demonstrated the feasibility of combining DSTAT with azacitidine, with several responses observed, suggesting this combination warrants further study.

Letermovir is approved by the Food and Drug Administration for cytomegalovirus (CMV) prophylaxis in CMV seropositive recipients of allogeneic stem cell transplantation (alloSCT) up to day 100. Letermovir use up to day 100 after alloSCT has demonstrated a significantly lower incidence of clinically significant CMV infection (csCMVi) at 24 weeks and an overall mortality benefit as far as 48 weeks after transplantation. We report data on csCMVi incidence beyond 24 weeks and overall survival (OS) beyond 48 weeks and outcomes for patients who had a prior alloSCT, are CMV seronegative with seropositive donor (D+/R-), or are high risk (defined as those receiving haploidentical transplants, mismatched transplants, T-cell-depleted grafts, umbilical cord blood transplants, prednisone ≥1 mg/kg or equivalent steroid use, or the use of 2 or more immunosuppressants). Additionally, risk factors for CMV-related mortality and possible extended duration of letermovir are reported. This is a single-center, retrospective cohort study of 333 alloSCTs with CMV seropositive donors or recipients performed at Siteman Cancer Center and Barnes-Jewish Hospital from January 2016 to June 2019. The primary endpoint of csCMVi at day 180 was 19.46% with letermovir and 39.13% without letermovir (P.0001). The secondary endpoints are as follows: day 100 csCMVi was 8.1% with letermovir and 34.8% without (P.0001), day 365 csCMVi was 24.8% with letermovir and 41.3% without (P = .001). Our multivariate analyses demonstrated that exposure to letermovir was associated with improved OS (hazard ratio [HR] 0.43; 95% confidence interval [CI] 0.25-0.77), nonrelapse mortality (HR 0.50; 95% CI 0.27-0.94) and CMV-related mortality (HR 0.40; 95% CI 0.16-0.95) during day 0 to day 99 but worse CMV-related mortality during day 180 to day 364 (HR 3.19; 95% CI 1.29-7.92). Patients with serum IgG levels400 mg/dL at day 100, high-risk transplants (P = .004), post-transplantation cyclophosphamide (PTCy; P = .001), and mismatched-unrelated donors (MMUD; P = .02) experienced increased CMV reactivation. The CMV D+/R- cohort demonstrated no difference in CMV reactivation overall (P = .19), but the subset receiving PTCy showed decreased reactivation with letermovir (P = .03). Discontinuation of letermovir at day 100 leads to increased incidence of late CMV reactivation and CMV-related mortality. Letermovir use in CMV recipient seropositive alloSCT may need to be extended. Serum IgG levels400 mg/dL at day 100 was associated with increased CMV reactivation. Patients with subclinical CMV viremia before transplantation, high-risk transplants, PTCy, or MMUD had decreased CMV reactivation with letermovir. Although there was no difference in CMV reactivation in the CMV D+/R- cohort, the subset treated with PTCy for acute graft-versus-host disease prophylaxis had decreased CMV reactivation with letermovir.

Introduction: Belumosudil (KD025) is a novel oral selective rho-associated coiled-coil kinase 2 (ROCK2) inhibitor specifically designed for the treatment of cGVHD, an immune-mediated inflammatory and fibrotic disorder. In a previous dose-finding study (KD025-208, N=54), two-thirds of patients, including those with fibrotic and inflammatory manifestations, achieved a partial or complete response with belumosudil. Herein, we report on the top-line results (6 months after the last patient in) from the pivotal phase 2 trial (ROCKstar [KD025-213], N=132). Methods: This phase 2, open-label, randomized, multicenter study evaluated belumosudil 200 mg QD (n=66) and BID (n=66) in patients with cGVHD who received 2 to 5 prior lines of therapy (LOT). Treatment continued until clinically significant progression of cGVHD. The primary end point was overall response rate (ORR), defined per the 2014 National Institutes of Health Consensus Criteria. Additional end points included duration of response (DOR), Lee Symptom Scale (LSS) score, failure-free survival (FFS), corticosteroid (CS) dose reductions and overall survival. The study was powered such that the lower bound of the 95% confidence interval (CI) excludes 30%, with appropriate multiplicity adjustment. Results: At enrollment, the median age was 56 years, the median time from cGVHD diagnosis to enrollment was 29 months, 67% of patients had severe cGVHD, 52% had ≥4 organs involved, 72% had received ≥3 prior LOT (including ibrutinib [n=46] or ruxolitinib [n=38]) and 73% were refractory to their last LOT. The baseline characteristics of both arms were well balanced. With a median follow-up of 8 months, the ORR (95% CI) with belumosudil 200 mg QD and BID was 73% (60%-83%) and 74% (62%-84%), respectively (Table 1). In patients who previously received ruxolitinib (29%), the ORR with belumosudil 200 mg QD and BID was 65% (41%-85%) and 72% (47%-90%), respectively. In patients who previously received ibrutinib (35%), the ORR with belumosudil 200 mg QD and BID was 73% (50%-89%) and 71% (49%-87%), respectively. High ORRs were seen in all patient subgroups, regardless of length of time from diagnosis to treatment, including those with severe cGVHD, involvement of ≥4 organs and a refractory response to prior LOT (Figure 1). The response rate was similar across all affected organs. The median time to response was 4 weeks. Of responders, 49% have maintained response for ≥20 weeks. The median DOR has not yet been reached. Clinically meaningful improvement (≥7-point reduction) in LSS score on consecutive assessments was observed in 39% and 33% of patients in the QD and BID groups, respectively. Both responders (43%) and nonresponders (17%) experienced a clinically meaningful improvement in LSS score. FFS was 77% (69%-84%) at 6 months. CS and calcineurin inhibitor discontinuations were seen in 18% and 13% of patients, respectively. Belumosudil was well tolerated, with >95% relative dose intensity in 83% of patients. Drug discontinuation occurred in 10% of patients due to possible drug-related adverse events (AEs), 3% due to progression of underlying disease and 12% due to progression of cGVHD. AEs were consistent with those expected in patients with cGVHD receiving CS and other immunosuppressants (Table 2). Common AEs included fatigue (32%), diarrhea (29%), nausea (26%), cough (24%), dyspnea (24%), upper respiratory tract infection (23%), peripheral edema (21%) and headache (20%). At least 1 serious AE occurred in 34% of patients. Twenty-three percent of patients had at least 1 liver-related investigation; the most common was increased gamma-glutamyltransferase (11%), and only 1 patient showed an increase in bilirubin. Eight patients died during the study; 5 due to AEs (1 possibly related to belumosudil) and 3 during long-term follow-up (>28 days after last dose). There were no reports of cytomegalovirus reactivation or infection. Conclusion: Treatment with belumosudil at both doses resulted in high ORRs across key subgroups, meeting the primary end point of this pivotal randomized trial in cGVHD. Responses were durable and clinically meaningful, irrespective of patient and cGVHD characteristics, and were seen in patients who previously received ruxolitinib and ibrutinib. Belumosudil was well tolerated, with limited and manageable AEs. Further studies will evaluate its use earlier in disease management. The 12-month data analysis will be presented at ASH 2020. Download : Download high-res image (508KB) Download : Download full-size image Disclosures Cutler: Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees; Kadmon: Consultancy, Membership on an entity's Board of Directors or advisory committees; Jazz: Consultancy, Membership on an entity's Board of Directors or advisory committees; Medsenic: Consultancy, Membership on an entity's Board of Directors or advisory committees; Generon: Consultancy, Membership on an entity's Board of Directors or advisory committees; Mesoblast: Consultancy, Membership on an entity's Board of Directors or advisory committees. Lee: Pfizer: Consultancy, Research Funding; Incyte: Consultancy, Research Funding; Amgen: Research Funding; Kadmon: Research Funding; AstraZeneca: Research Funding; Novartis: Research Funding; Takeda: Research Funding; Syndax: Research Funding. Rotta: Merck: Speakers Bureau; Jazz Pharma: Speakers Bureau. Ramakrishnan: Amgen: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Cigna: Honoraria. Eiznhamer: Kadmon Corporation, LLC: Current Employment, Current equity holder in publicly-traded company. Schueller: Kadmon Corporation, LLC: Current Employment, Current equity holder in publicly-traded company. Yang: Kadmon Corporation, LLC: Current Employment, Current equity holder in publicly-traded company. Green: Kadmon Corporation, LLC: Current Employment, Current equity holder in publicly-traded company. Aggarwal: Kadmon Corporation, LLC: Consultancy; Angiocrine Bioscience, Inc: Current Employment, Other: stock options. Blazar: BlueRock Therapeutics: Research Funding; BlueRock Therapeuetic: Consultancy; Fate Therapeutics Inc.: Research Funding; Magenta Therapeutics: Consultancy; Childrens' Cancer Research Fund: Research Funding; KidsFirst Fund: Research Funding; Tmunity: Other: Co-founder. Jagasia: Ocugen: Other; Mallinckrodt: Research Funding; Janssen: Research Funding.

Infection or vaccination induces a population of long-lived bone marrow plasma cells (BMPCs) that are a persistent and essential source of protective antibodies1–5. Whether this population is induced in patients infected with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unknown. Recent reports have suggested that SARS-CoV-2 convalescent patients experience a rapid decay in their antigen-specific serum antibodies, raising concerns that humoral immunity against this virus may be short-lived6–8. Here we show that in patients who experienced mild infections (n=73), serum anti-SARS-CoV-2 spike (S) antibodies indeed decline rapidly in the first 3 to 4 months after infection. However, this is followed by a more stable phase between 4- and 8-months after infection with a slower serum anti-S antibody decay rate. The level of serum antibodies correlated with the frequency of S-specific long-lived BMPCs obtained from 18 SARS-CoV-2 convalescent patients 7 to 8 months after infection. S-specific BMPCs were not detected in aspirates from 11 healthy subjects with no history of SARS-CoV-2 infection. Comparable frequencies of BMPCs specific to contemporary influenza virus antigens or tetanus and diphtheria vaccine antigens were present in aspirates in both groups. Circulating memory B cells (MBCs) directed against the S protein were detected in the SARS-CoV-2 convalescent patients but not in uninfected controls, whereas both groups had MBCs against influenza virus hemagglutinin. Overall, we show that robust antigen specific long-lived BMPCs and MBCs are induced after mild SARS-CoV-2 infection of humans.

PURPOSE Physicians treating hematologic malignancies increasingly order targeted sequencing panels to interrogate recurrently mutated genes. The precise impact of these panels on clinical decision making is not well understood. METHODS Here, we report our institutional experience with a targeted 40-gene panel (MyeloSeq) that is used to generate a report for both genetic variants and variant allele frequencies for the treating physician (the limit of mutation detection is approximately one AML cell in 50). RESULTS In total, 346 sequencing reports were generated for 325 patients with suspected hematologic malignancies over an 8-month period (August 2018 to April 2019). To determine the influence of genomic data on clinical care for patients with acute myeloid leukemia (AML), we analyzed 122 consecutive reports from 109 patients diagnosed with AML and surveyed the treating physicians with a standardized questionnaire. The panel was ordered most commonly at diagnosis (61.5%), but was also used to assess response to therapy (22.9%) and to detect suspected relapse (15.6%). The panel was ordered at multiple timepoints during the disease course for 11% of patients. Physicians self-reported that 50 of 114 sequencing reports (44%) influenced clinical care decisions in 44 individual patients. Influences were often nuanced and extended beyond identifying actionable genetic variants with US Food and Drug Administration–approved drugs. CONCLUSION This study provides insights into how physicians are currently using multigene panels capable of detecting relatively rare AML cells. The most influential way to integrate these tools into clinical practice will be to perform prospective clinical trials that assess patient outcomes in response to genomically driven interventions.

Clonal hematopoiesis is associated with various age-related morbidities. Error-corrected sequencing (ECS) of human blood samples, with a limit of detection of ≥0.0001, has demonstrated that nearly every healthy individual >50 years old harbors rare hematopoietic clones below the detection limit of standard high-throughput sequencing. If these rare mutations confer survival or proliferation advantages, then the clone(s) could expand after a selective pressure such as chemotherapy, radiotherapy, or chronic immunosuppression. Given these observations and the lack of quantitative data regarding clonal hematopoiesis in adolescents and young adults, who are more likely to serve as unrelated hematopoietic stem cell donors, we completed this pilot study to determine whether younger adults harbored hematopoietic clones with pathogenic mutations, how often those clones were transferred to recipients, and what happened to these clones over time after transplantation. We performed ECS on 125 blood and marrow samples from 25 matched unrelated donors and recipients. Clonal mutations, with a median variant allele frequency of 0.00247, were found in 11 donors (44%; median, 36 years old). Of the mutated clones, 84.2% of mutations were predicted to be molecularly pathogenic and 100% engrafted in recipients. Recipients also demonstrated de novo clonal expansion within the first 100 days after hematopoietic stem cell transplant (HSCT). Given this pilot demonstration that rare, pathogenic clonal mutations are far more prevalent in younger adults than previously appreciated, and they engraft in recipients and persist over time, larger studies with longer follow-up are necessary to correlate clonal engraftment with post-HSCT morbidity.

Clinical- and biomarker-based tools may identify a lower-risk acute graft-versus-host disease (GVHD) population amenable to novel, reduced-intensity treatments. Previous data suggest sirolimus may rival standard of care prednisone. We conducted a National Heart, Lung, and Blood Institute/National Cancer Institute-funded Blood and Marrow Transplant Clinical Trials Network multicenter, open-label, randomized phase 2 trial to estimate the difference in day 28 complete response (CR)/partial response (PR) rates for sirolimus vs prednisone as initial treatment of patients with standard risk (SR) acute GVHD as defined by the Minnesota (MN) GVHD Risk Score and Ann Arbor (AA1/2) biomarker status. A total of 127 MN-SR patients were randomized (1:1), and 122 were AA1/2 (sirolimus, n = 58; prednisone, n = 64). Others were AA3 (n = 4), or AA status missing (n = 1). The day 28 CR/PR rates were similar for sirolimus 64.8% (90% confidence interval [CI], 54.1%-75.5%) vs 73% (90% CI, 63.8%-82.2%) for prednisone. The day 28 rate of CR/PR with prednisone ≤0.25 mg/kg/day was significantly higher for sirolimus than prednisone (66.7% vs 31.7%; P < .001). No differences were detected in steroid-refractory acute GVHD, disease-free survival, relapse, nonrelapse mortality, or overall survival. Sirolimus was associated with reduced steroid exposure and hyperglycemia, reduced grade 2 to 3 infections, improvement in immune suppression discontinuation and patient-reported quality of life, and increased risk for thrombotic microangiopathy. For patients with clinical- and biomarker-based SR acute GVHD, sirolimus demonstrates similar overall initial treatment efficacy as prednisone. In addition, sirolimus therapy spares steroid exposure and allied toxicity, does not compromise long-term survival outcomes, and is associated with improved patient-reported quality of life. This trial was registered at www.clinicaltrials.gov as #NCT02806947.

Amphiregulin (AREG) is an epidermal growth factor receptor ligand that can restore integrity to damaged intestinal mucosa in murine models of acute graft-versus-host disease (aGVHD). We previously reported that circulating AREG is elevated in late-onset aGVHD (occurring after 100 days posttransplant), but its clinical relevance in the context of aGVHD risk is unknown. We measured AREG in 251 aGVHD onset blood samples from Blood and Marrow Clinical Trials Network (BMT CTN) primary treatment trials and determined their association with GVHD severity, day 28 complete or partial response (CR/PR) to first-line therapy, overall survival (OS), and nonrelapse mortality (NRM). Every doubling of plasma AREG was associated with a 33% decrease in the odds of day 28 CR/PR (odds ratio [OR], 0.67; P < .01). An AREG threshold of 33 pg/mL or greater divided patients with Minnesota standard-risk (SR) aGVHD into a distinct group with a significantly lower likelihood of: day 28 CR/PR (72% vs 85%; P = .02); greater 2-year NRM (42% vs 15%; P < .01); and inferior OS (40% vs 66%; P < .01). High AREG ≥ 33 pg/mL also stratified patients with Minnesota high-risk (HR) aGVHD: day 28 CR/PR (54% vs 83%; P = .03) and 2-year NRM (53% vs 11%; P < .01), with a trend toward inferior 2-year OS (37% vs 60%; P = .09). High-circulating AREG (≥33 pg/mL) reclassifies patients into HR subgroups and thereby further refines the Minnesota aGVHD clinical risk score.

Inhibition of the Janus-associated kinases (JAK) with ruxolitinib (RUX) reduces graft-versus-host disease (GVHD) in preclinical and clinical models. In total 19 allograft recipients with moderate/severe steroid-dependent chronic GVHD received RUX as ≥2nd line salvage. RUX was well tolerated, and led to complete/partial resolution of oral (92/7%), cutaneous (82/0%), hepatic (71/28%), gastro-intestinal (75/17%), musculoskeletal (33/67%), pulmonary (0/80%), scleroderma (0/75%), vaginal (0/75%), and ocular (0/100%) chronic GVHD. Overall 18 achieved partial response and 1 complete response according to NIH Consensus Criteria. Responses occurred early and were sustained which enabled discontinuation (68%) or reduction of steroids to physiologic doses (21%). We conclude that RUX is an effective steroid-sparing agent in chronic GVHD.

The most transformative approach for controlling chronic Graft-versus-Host Disease (cGvHD) after allogeniec hematopoietic cell transplantation (alloHCT) would be the prevention of its most severe and irreversible clinical manifestations instead of treating already established disease. Belimumab is a monoclonal antibody, approved for treatment of systemic lupus erythematosus and active lupus nephritis, which inhibits binding of B-cell-activating factor (BAFF) to its receptors on B cells, thus inhibiting the survival of autoreactive B cells. Given the role of B cells in cGvHD pathophysiology and the now substantiated role of BAFF in promoting B Cell Receptor signaling in cGvHD (Jia W et al Blood 2021), belimumab might have a role in prevention of cGvHD. We hypothesized that targeting BAFF early after alloHCT would be well-tolerated and have a favorable effect on the incidence and severity of cGvHD. We are presenting data on the first 8/10 patients (Pts) enrolled in the single-center, investigator-initiated phase-1 trial. Belimumab was administered i.v. at 10 mg/kg every 2 weeks for 3 doses followed by 4 doses at monthly intervals, for a total of 7 doses, starting 50-80 days after alloHCT. All Pts were adults who received mobilized peripheral blood grafts from fully matched related or unrelated donors after myeloablative or non-myeloablative conditioning. GvHD prophylaxis was with tacrolimus and methotrexate; one Pt received post-transplant cyclophosphamide. All Pts were in complete remission on day +30 after alloHCT. Pts who received ≥1 dose of belimumab were evaluable for safety and ≥2 doses for efficacy assessment. cGvHD was diagnosed according to the NIH criteria. All analyses are descriptive. Specimens for correlative studies are cryopreserved until the study end. We found that Pts tolerated belimumab well, with no reported grade ≥3 treatment-related adverse events. There were no significant infections or myelosuppression. Seven out of eight Pts on the study received all 7 doses of belimumab, as planned. Of those 7 Pts, 5 Pts are without any evidence of cGvHD and completely off immunosuppression at the median of 18 months (mo) after completing belimumab (median of 24 mo after alloHCT). Seven mo after completing belimumab on study, 1 Pt developed cGvHD involving skin, eyes and liver, and died from complications of pneumonia and liver failure due to longstanding hemochromatosis, iron overload and possible liver GvHD. Another Pt relapsed with leukemia 1 mo after completing belimumab. He is now in remission after treatment with enasidenib and 2 donor lymphocyte infusions (DLI), 12 mo after completing belimumab (18 mo after alloHCT); he developed mild eye GvHD following DLI. One out of eight Pts on the study stopped treatment early, after receiving only 3 doses, due to thrombocytopenia (unrelated to belimumab) and insurance issues. He was found to have relapsed lymphoma 3 mo later, was treated with venetoclax and DLI, and remains in remission with no evidence of cGvHD 15 mo after stopping belimumab. Two additional patients are being enrolled. Immune reconstitution studies are showing that B-cell counts remain low 1 year out of transplant in all Pts (Figure 1). This preliminary data describes for the first time the use of belimumab for prophylaxis of cGvHD. Overall, belimumab was very well tolerated. Only 1 Pt on the study developed cGvHD. It is worth noting that his cGvHD developed 7 mo after completing belimumab suggesting that a longer duration of therapy should be tested in future studies. The 2 Pts with relapsed disease both had high risk malignancies. Risk stratification of high risk patients will be critical in future prospective studies. While more Pts are needed to further assess the impact of prophylactic belimumab on the incidence of cGVHD, these preliminary results are encouraging. Absence of severe infections is reassuring. B-cell reconstitution was delayed, as expected. Ongoing correlative studies will further evaluate BAFF levels and B-cell subset reconstitution after alloHCT. Figure 1 Figure 1. Disclosures Pusic: Syndax: Other: Advisory Board. Sarantopoulos: Rigel: Other: Advisory Board. Uy: Macrogenics: Research Funding; Jazz: Consultancy; Genentech: Consultancy; Astellas: Honoraria, Speakers Bureau; Novartis: Consultancy; AbbVie: Consultancy; GlaxoSmithKline: Consultancy; Agios: Consultancy. OffLabel Disclosure: Drug: Belimumab This study: Belimumab for prophylaxis of chronic GvHD. Approved indication: Belimumab is approved for treatment of systemic lupus erythematosus and active lupus nephritis.

Background: Axatilimab (Axa) is an IgG4 humanized monoclonal antibody with high affinity binding to CSF-1R. Axa blocks CSF1 and IL-34 binding and activation of CSF-1R signaling, a key pathway involved in the expansion and infiltration of donor-derived macrophages that mediate chronic graft-versus-host disease (cGVHD). We previously reported preliminary phase (Ph) 1 data demonstrating clinical activity and safety of Axa in patients with active cGVHD (Arora, ASH 2020). Here, we provide updated results, including Ph 2 clinical data, for doses chosen to move forward in a global, randomized pivotal study, AGAVE-201 (SNDX-6352-504). Methods: SNDX-6352-0503 is a Ph 1/2 study evaluating safety, tolerability, and efficacy of Axa in pts ≥6 years of age with active cGVHD despite ≥2 prior lines of systemic therapy. Ph 1 evaluated Axa at doses of 0.15mg/kg (n=1), 0.5mg/kg (n=1), 1mg/kg (n=3), and 3mg/kg (n=6) Q2W and 3mg/kg Q4W (n=6). The Ph 2 dose expansion evaluated Axa at 1mg/kg Q2W (n=23) with a primary objective of overall response rate (CR+PR) at 6 months. The data cutoff was 28 Jun 2021. Results: Forty pts (17 Ph 1 and 23 Ph 2) were enrolled and received at least 1 dose of axatilimab. Median age was 59 y (range, 16-73). Pts had received a median of 4 prior lines of treatment (range, 1-11), including ibrutinib (n=25), ruxolitinib (n=21), and belumosudil (n=8). Pts had a median of 4 involved organ systems at baseline (range, 1-9). At the time of the data cut, 22 pts (Ph 1, n=6; Ph 2, n=16) were continuing study treatment. Reasons for discontinuation included progression (n=5, 13%), physician decision (n=5, 13%), adverse events (AEs) (n=4, 10%; grade [Gr]) 3 periorbital edema, Gr 3 hypersensitivity reaction, Gr 4 CPK increased, Gr 5 fall (n=1 each), other (n=2, 5%), and withdrawal of consent (n=2, 5%). Thirty-eight pts were evaluable for response across Ph 1 & Ph 2. Overall response rate was 66% (n=25/38) and similar in pts previously treated with ibrutinib (n=16/24; 67%), ruxolitinib (n=13/20; 65%), and belumosudil (n=4/7; 57%). Response rates were similar for moderate severity cGVHD (60% [6/10]) vs severe cGVHD (70% [19/27]). A 7-point improvement in the normalized Lee Symptom score was seen in 54% (n=19/35) of pts (Fig 1). Focusing on the 32 pts treated at 2 of the doses selected to move forward (1mg/kg Q2W [n=26] and 3 mg/kg Q4W [n=6]), AEs related to Axa occurred in 66% (n=21/32) of pts with 13% (n=4/32) of pts experiencing grade ≥3 related-AEs. At the 1mg/kg Q2W dose, 62% (n=16/26) of pts experienced a related-AE with 8% (n=2/26) of pts experiencing grade ≥3 related-AEs (hypersensitivity, septic arthritis; both grade 3). Related-AEs, regardless of grade, in the 32 pts demonstrate a trend toward dose dependency (1mg/kg Q2W vs 3 mg/kg Q4W) with a higher proportion having elevations in AST (23% vs 50%), CPK (12% vs 67%), ALT (12% vs 33%), lipase (12% vs 50%), and incidence of periorbital edema (8% vs 50%) in the 3mg/kg Q4W cohort (Table 1). Transient elevated circulating enzyme levels have not been associated with hepatotoxicity or any other end-organ damage and are likely due to CSF-1R blockade on Kupffer cells, which are liver macrophages that mediate clearance of these enzymes. Importantly, the risk of infection was low, and no cases of viral reactivation were reported (cytomegalovirus, Epstein-Barr, and/or herpes simplex virus). Of the 32 pts treated at 1mg/1kg Q2W or 3mg/kg Q4W, 30 pts were considered evaluable for response (2 pts had not undergone a postbaseline assessment at the time of the data cut). A best overall response rate (CR+PR) of 70% (75% [18/24] 1mg/kg Q2W; 50% [3/6] 3mg/kg Q4W) as defined by the 2014 NIH cGVHD Consensus Criteria was observed. Responses were noted in difficult-to-treat organ manifestations, with 31% (n=4/13) experiencing a response in lung, 19% (n=5/27) in skin, and 57% (n=13/23) in joints and fascia. Median time to first response was 0.95 months (Fig 2). Conclusions: Axa is a novel agent targeting a pathway different than other cGVHD treatments. Data from this Ph 1/2 study demonstrate the safety and clinical activity of Axa in heavily pre-treated pts with active cGVHD, particularly those with fibrotic manifestations. A randomized pivotal study (AGAVE-201) has started enrolling a similar pt population, evaluating doses of 1 mg/kg Q2W and 3mg/kg Q4W, along with a lower dose of 0.3mg/kg Q2W. Figure 1 Figure 1. Disclosures Lee: Syndax: Research Funding; Takeda: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Research Funding; National Marrow Donor Program: Membership on an entity's Board of Directors or advisory committees; Kadmon: Research Funding; AstraZeneca: Research Funding; Incyte: Research Funding; Janssen: Other; Amgen: Research Funding. Arora: Syndax: Research Funding; Pharmacyclics: Research Funding; Kadmom: Research Funding. Defilipp: Incyte Corp.: Research Funding; Regimmune Corp.: Research Funding; Omeros, Corp.: Consultancy; Syndax Pharmaceuticals, Inc: Consultancy. Abu Zaid: Syndax: Consultancy, Research Funding; Pieris: Current equity holder in publicly-traded company; Pharamcyclic: Research Funding; Incyte: Research Funding. Di Stasi: Syndax Pharmaceutical: Honoraria, Membership on an entity's Board of Directors or advisory committees; University of Alabama at Birmingham: Current Employment. Radojcic: Syndax Pharmaceuticals: Research Funding; Regeneron Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Allakos: Membership on an entity's Board of Directors or advisory committees. Meyers: Nuvalent: Consultancy, Membership on an entity's Board of Directors or advisory committees; Syndax Pharmaceuticals, Inc: Current Employment, Current equity holder in publicly-traded company, Current holder of individual stocks in a privately-held company, Patents & Royalties. Qamoos: Syndax Pharmaceuticals: Current Employment. Ordentlich: Novartis: Current equity holder in publicly-traded company, Divested equity in a private or publicly-traded company in the past 24 months; Patrys Lmtd: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Syndax Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company, Divested equity in a private or publicly-traded company in the past 24 months, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Twenty-eight Seven Therapeutics: Consultancy; Cymabay Therapeutics: Current equity holder in publicly-traded company; Pfizer: Current equity holder in publicly-traded company; Viking Therapeutics: Current equity holder in publicly-traded company. Quaranto: Syndax Pharmaceuticals, LLC: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Schmitt: Syndax Pharmaceuticals, LLC: Current Employment, Current holder of stock options in a privately-held company; Fractyl Laboratories Inc. (Now Fractyl Health): Ended employment in the past 24 months. Gu: Syndax: Current Employment, Current equity holder in publicly-traded company; AstraZeneca: Ended employment in the past 24 months. Pusic: Syndax: Other: Advisory Board. Kitko: Horizon: Membership on an entity's Board of Directors or advisory committees; Co-investigator on two NIH grants as part of the cGVHD consortium: Research Funding; PER: Other: PER - CME educational talks about GVHD; Vanderbilt University Medical Center: Current Employment.

Bronchiolitis obliterans syndrome (BOS) is a highly morbid form of chronic graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation (HCT). Several plasma proteins have been identified as biomarkers for BOS after lung transplantation. The relevance of these biomarkers in BOS patients after allogeneic HCT has not been examined. We hypothesized that biomarkers associated with BOS after lung transplantation are also associated with BOS after allogeneic HCT. We tested plasma samples from 33 adult HCT patients who participated in a phase II multicenter study of fluticasone, azithromycin, and montelukast (FAM) treatment for new-onset BOS (NCT01307462), and matched control samples of HCT patients who had non-BOS chronic GVHD (n = 31) and those who never experienced chronic GVHD (n = 29) (NCT00637689 and NCT01902576). Candidate biomarkers included matrix metalloproteinase-9 (MMP-9), MMP-3, and chitinase-3-like-1 glycoprotein (YKL-40). MMP-9 concentrations were higher in the patients with BOS compared with those with non-BOS chronic GVHD (P = .04) or no chronic GVHD (P.001). MMP-3 concentrations were higher in patients with BOS (P.001) or non-BOS chronic GVHD (P.001) compared with those with no chronic GVHD. YKL-40 concentrations did not differ statistically among the 3 groups. MMP-9 concentrations before starting FAM therapy were higher in patients who experienced treatment failure within 6 months compared with those with treatment success (P = .006), whereas MMP-3 or YKL-40 concentrations did not differ statistically between these 2 groups. Patients with an MMP-9 concentration ≥200,000 pg/mL before starting FAM therapy had worse overall survival compared with those with lower MMP-9 concentrations. Our data suggest that plasma MMP-9 concentration could serve as a relevant biomarker at diagnosis of BOS after allogeneic HCT for prognostication of survival and for prediction of treatment response. Further validation is needed to confirm our findings.

Development of graft-versus-host disease (GvHD) is a rare complication after transfusions or solid organ transplantation. Patients typically present with a skin rash, diarrhea, liver failure, and bone marrow aplasia. A diagnosis of transfusion/transplantation associated-GvHD is made based on the clinical and histologic evidence, yet it is often delayed due to the nonspecific symptoms attributed to the patient's underlying illness. Several therapeutic approaches are being used including both increasing and withdrawing immunosuppression, and the use of cellular therapies. Unfortunately, the success rate of these approaches is low and the mortality of this complication is very high. New approaches are needed. We report on three cases of GvHD developing after solid organ transplantation treated with ruxolitinib.

IMPORTANCE: Leukemia cutis (LC) is an important yet understudied extramedullary manifestation of leukemia. Previous reports have suggested poor prognosis for patients with LC, but these reports have largely consisted of descriptive studies with a limited number of patients. OBJECTIVES: To identify patient factors associated with LC and characterize the association of LC with the course of acute myeloid leukemia (AML). DESIGN, SETTING, AND PARTICIPANTS: This retrospective, matched-cohort study included 1683 patients with AML diagnosed from January 1, 2005, to April 1, 2017, with and without biopsy-proven LC seen at a single-center, tertiary care hospital in St Louis, Missouri. To specifically evaluate differences in survival, propensity scoring was used to match patients with AML with LC to patients with AML without LC off the logit of propensity score based on age, race/ethnicity, sex, and leukemia type. Kaplan-Meier methods were used to compare cumulative probability survival. Matched survival analysis was performed with extended Cox regression to determine factors associated with leukemia-specific and overall survival. MAIN OUTCOMES AND MEASURES: Leukemia-specific survival and overall survival. RESULTS: A total of 1683 patients were reviewed, including 78 patients with biopsy-proven LC of the AML type and 1605 patients with AML without LC. A total of 62 of the patients with AML and LC (mean [SD] age, 58.2 [11.7] years; 33 [53.2%] male) were matched in a 1:3 ratio to 186 patients with AML without LC (mean [SD] age, 58.2 [13.5] years; 103 [55.4%] male). The 5-year survival among the 62 patients with AML with LC was 8.6%, shorter than the 28.3% among the 186 matched patients with AML without LC. Matched survival analysis revealed that patients with AML and LC compared with those without LC had hazard ratios of 2.06 (95% CI, 1.26-3.38; P = .004) for leukemia-specific death and of 1.66 (95% CI, 1.06-2.60; P = .03) for all-cause death. In addition, matched patients with LC had greater odds of extramedullary organ burden (odds ratio, 3.48; 95% CI, 1.72-7.05; P

Chronic graft-versus-host disease (cGVHD) is a life-threatening complication of allogeneic stem cell transplantation. In a Phase 1b/2, open-label study (PCYC-1129; ClinicalTrials.gov identifier NCT02195869) involving 42 patients with active cGVHD who were steroid-dependent or -refractory, the activity and safety of ibrutinib, a once-daily inhibitor of Bruton's tyrosine kinase, was demonstrated. Here we report extended follow-up for patients in this study. After a median follow-up of 26 months (range, .53 to 36.7 months), best overall response rate in the all treated population was 69% (29 of 42), with 13 patients (31%) achieving a complete response and 16 patients (38%) achieving a partial response. Sustained responses of ≥20, ≥32, and ≥44 weeks were seen in 20 (69%), 18 (62%), and 16 (55%) of the 29 responders, respectively. Of 26 patients with ≥2 involved organs, 19 (73%) showed responses in ≥2 organs. Six of 10 patients (60%) with ≥3 involved organs showed responses in ≥3 organs. Eleven of 18 patients (61%) who had sclerosis at baseline showed a sclerotic response (39% with complete response, 22% with partial response). Twenty-seven of 42 patients (64%) reached a corticosteroid dose of.15 mg/kg/day during the study; 8 discontinued corticosteroid treatment and remained off corticosteroid at study closure. Safety findings for this updated analysis were consistent with the safety profile seen at the time of the original analysis. Common grade ≥3 adverse events (AEs) were pneumonia (n = 6), fatigue (n = 5), and diarrhea (n = 4). The onset of new grade ≥3 AEs decreased from 71% in the first year of treatment to 25% in the second year (n = 12). AEs leading to discontinuation occurred in 18 patients (43%). At a median follow-up of2 years, ibrutinib continued to produce durable responses in patients with cGVHD who had failed previous systemic therapy. In this pretreated, high-risk population, clinically meaningful benefit and an acceptable safety profile were observed with additional follow-up for ibrutinib. These results demonstrate a substantial advance in the therapeutic management of patients with cGVHD.

Summary Background Prevention of graft-versus-host disease (GvHD) without malignant relapse is the overall goal of allogeneic haemopoietic cell transplantation (HCT). We aimed to evaluate regimens using either maraviroc, bortezomib, or post-transplantation cyclophosphamide for GvHD prophylaxis compared with controls receiving the combination of tacrolimus and methotrexate using a novel composite primary endpoint to identify the most promising intervention to be further tested in a phase 3 trial. Methods In this prospective multicentre phase 2 trial, adult patients aged 18–75 years who received reduced-intensity conditioning HCT were randomly assigned (1:1:1) by random block sizes to tacrolimus, mycophenolate mofetil, and post-transplantation cyclophosphamide (cyclophosphamide 50 mg/kg on days 3 and 4, followed by tacrolimus starting on day 5 and mycophenolate mofetil starting on day 5 at 15 mg/kg three times daily not to exceed 1 g from day 5 to day 35); tacrolimus, methotrexate, and bortezomib (bortezomib 1·3 mg/m2 intravenously on days 1, 4, and 7 after HCT); or tacrolimus, methotrexate, and maraviroc (maraviroc 300 mg orally twice daily from day −3 to day 30 after HCT). Methotrexate was administered as a 15 mg/m2 intravenous bolus on day 1 and 10 mg/m2 intravenous bolus on days 3, 6, and 11 after HCT; tacrolimus was given intravenously at a dose of 0·05 mg/kg twice daily (or oral equivalent) starting on day −3 (except the post-transplantation cyclophosphamide, as indicated), with a target level of 5–15 ng/mL. Tacrolimus was continued at least until day 90 and was tapered off by day 180. Each study group was compared separately to a contemporary non-randomised prospective cohort of patients (control group) who fulfilled the same eligibility criteria as the trial, but who were treated with tacrolimus and methotrexate at centres not participating in the trial. The primary endpoint (GvHD-free, relapse-free survival [GRFS]) was defined as the time from HCT to onset of grade 3–4 acute GvHD, chronic GvHD requiring systemic immunosuppression, disease relapse, or death. The study was analysed by modified intention to treat. The study is closed to accrual and this is the planned analysis. This trial is registered with ClinicalTrials.gov , number NCT02208037 . Findings Between Nov 17, 2014, and May 18, 2016, 273 patients from 31 US centres were randomly assigned to the three study arms: 89 to tacrolimus, methotrexate, and bortezomib; 92 to tacrolimus, methotrexate, and maraviroc; 92 to tacrolimus, mycophenolate mofetil, and post-transplantation cyclophosphamide; and six were excluded. Between Aug 1, 2014, and Sept 14, 2016, 224 controls received tacrolimus and methotrexate. Controls were generally well matched except for more frequent comorbidities than the intervention groups and a different distribution of types of conditioning regimens used. Compared with controls, the hazard ratio for GRFS was 0·72 (90% CI 0·54–0·94; p=0·044) for tacrolimus, mycophenolate mofetil, and post-transplantation cyclophosphamide, 0·98 (0·76–1·27; p=0·92) for tacrolimus, methotrexate, and bortezomib, and 1·10 (0·86–1·41; p=0·49) for tacrolimus, methotrexate, and maraviroc. 238 patients experienced grade 3 or 4 toxicities: 12 (13%) had grade 3 and 67 (73%) grade 4 events with tacrolimus, mycophenolate mofetil, and post-transplantation cyclophosphamide; ten (11%) had grade 3 and 68 (76%) had grade 4 events with tacrolimus, methotrexate, and bortezomib; and 18 (20%) had grade 3 and 63 (68%) had grade 4 events with tacrolimus, methotrexate, and maraviroc. The most common toxicities were haematological (77 [84%] for tacrolimus, mycophenolate mofetil, and post-transplantation cyclophosphamide; 73 [82%] for tacrolimus, methotrexate, and bortezomib; and 78 [85%] for tacrolimus, methotrexate, and maraviroc) and cardiac (43 [47%], 44 [49%], and 43 [47%], respectively). Interpretation Tacrolimus, mycophenolate mofetil, and post-transplantation cyclophosphamide was the most promising intervention, yielding the best GRFS; this regimen is thus being prospectively compared with tacrolimus and methotrexate in a phase 3 randomised trial. Funding US National Health, Lung, and Blood Institute; National Cancer Institute; National Institute of Allergy and Infectious Disease; and Millennium Pharmaceuticals.