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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.

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.

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.

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.

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.

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.

BackgroundThe molecular determinants of clinical responses to decitabine therapy in patients with acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS) are unclear. MethodsWe enrolled 84 adult patients with AML or MDS in a single-institution trial of decitabine to identify somatic mutations and their relationships to clinical responses. Decitabine was administered at a dose of 20 mg per square meter of body-surface area per day for 10 consecutive days in monthly cycles. We performed enhanced exome or gene-panel sequencing in 67 of these patients and serial sequencing at multiple time points to evaluate patterns of mutation clearance in 54 patients. An extension cohort included 32 additional patients who received decitabine in different protocols. ResultsOf the 116 patients, 53 (46%) had bone marrow blast clearance (

Late acute (LA) graft-versus-host disease (GVHD) is persistent, recurrent, or new-onset acute GVHD symptoms occurring >100 days after allogeneic hematopoietic cell transplantation (HCT). The aim of this analysis is to describe the onset, course, morbidity, and mortality of and examine angiogenic factors associated with LA GVHD. A prospective cohort of patients (n = 909) was enrolled as part of an observational study within the Chronic GVHD Consortium. Eighty-three patients (11%) developed LA GVHD at a median of 160 (interquartile range, 128-204) days after HCT. Although 51 out of 83 (61%) achieved complete or partial response to initial therapy by 28 days, median failure-free survival was only 7.1 months (95% confidence interval, 3.4-19.1 months), and estimated overall survival (OS) at 2 years was 56%. Given recently described alterations of circulating angiogenic factors in classic acute GVHD, we examined whether alterations in such factors could be identified in LA GVHD. We first tested cases (n = 55) and controls (n = 50) from the Chronic GVHD Consortium and then validated the findings in 37 cases from Mount Sinai Acute GVHD International Consortium. Plasma amphiregulin (AREG; an epidermal growth factor [EGF] receptor ligand) was elevated, and an AREG/EGF ratio at or above the median was associated with inferior OS and increased nonrelapse mortality in both cohorts. Elevation of AREG was detected in classic acute GVHD, but not chronic GVHD. These prospective data characterize the clinical course of LA GVHD and demonstrate alterations in angiogenic factors that make LA GVHD biologically distinct from chronic GVHD.

Rationale: The natural history of lung function in patients with bronchiolitis obliterans syndrome (BOS) after allogeneic hematopoietic cell transplant is poorly characterized. Understanding the trajectory of lung function is necessary for prompt clinical recognition and treatment and also for the rational design of prospective studies.Objectives: To describe the longitudinal trajectory of lung function parameters, including FEV1, in patients with BOS after hematopoietic cell transplant.Methods: Subjects with BOS defined by National Institutes of Health consensus guidelines criteria from a recent multicenter prospective trial of combination treatment with fluticasone, azithromycin and montelukast and a retrospective cohort from Fred Hutchinson Cancer Research Center were included. Longitudinal change in FEV1 for each patient was calculated on the basis of available pulmonary function tests in three periods: pre-BOS, from BOS diagnosis to 6 months, and 6–18 months after diagnosis. The effect of treatment o...

Donor lymphocyte infusion (DLI) without prophylactic immunosuppression has been used for relapsed AML after allogeneic stem cell transplant (allo-SCT). However DLI is associated with an increased incidence of acute Graft vs. Host Disease (aGVHD). In mice, administration of azacitidine (AzaC) on days 4, 6, 8, and 10 post DLI increases regulatory T cell (Treg) numbers and prevents GVHD without hindering Graft vs. Leukemia (GVL). Based on these findings, we conducted a phase 1 study of AzaC post DLI for AML relapse post allo-SCT. AzaC was administered on days 4, 6, 8 and 10 post-DLI. Dose escalation was done using a 3+3 design with three AzaC dose levels: 30mg/m(2) (level -1), 45mg/m(2) (level 1) and 75mg/m(2) (level 2). Three patients were treated in the 45mg/m(2) dose level and 5 patients were treated in the 75mg/m(2) dose level; no DLTs or grade 3-5 treatment related toxicities were observed. After a median follow-up of 5.2 months, no patients developed grade III-IV aGVHD and no patients died of aGVHD. Six out of 8 patients in the treatment group responded to treatment including two cytogenetic complete remissions, one hematologic complete remission, and three complete remissions with incomplete count recovery. In conclusion, administration of AzaC early post DLI is well tolerated and can potentially prevent GVHD after DLI. Further studies are required to evaluate the effect of azacitidine early post DLI on GVHD and GVL.

Conditioning-related gut toxicity can result in a protein-losing enteropathy manifesting as a decline in serum albumin in the peritransplant period. Inspired by the pathogenesis of acute graft-versus-host disease (aGVHD), we hypothesized that the magnitude of decline in serum albumin from the day of conditioning initiation until its nadir in the first 2 weeks after hematopoietic cell transplantation HCT (DeltaAlb) predicts the risk for subsequent severe aGVHD. We reviewed the medical records of all 88 patients with acute myeloid leukemia or myelodysplastic syndrome who underwent highly mucotoxic myeloablative (busulfan/cyclophosphamide or cyclophosphamide/total body irradiation) allogeneic HCT from a matched related donor (MRD) or matched unrelated donor (MUD) at our institution between January 1, 2012 and January 1, 2015. Severe aGVHD was associated with MUD (47% versus 14% with MRD; P = .001) and DeltaAlb, which was significantly greater among patients who developed versus did not develop severe aGVHD (1.2 ± .5 versus .8 ± .4 g/dL, respectively; P .001). In multivariate analysis DeltaAlb remained a significant predictor of severe aGVHD (odds ratio, 5.68; 95% CI, 1.65 to 19.64; P = .006; area under the ROC curve, .74; 95% CI, .63 to .86; P .001). The best cutoff for DeltaAlb to predict severe aGVHD was .9, with a sensitivity, specificity, and overall classification accuracy of 77%, 66%, and 69%, respectively. The model was validated using the bootstrap technique, with no significant change in its performance. These results were not generalizable to a cohort of 30 patients who received less mucotoxic myeloablative or reduced-intensity conditioning. In conclusion, with mucotoxic myeloablative HCT, each .1-g/dL increase in DeltaAlb was associated with an approximately 23% increase in the odds of developing severe aGVHD. As an early biomarker of gut damage, DeltaAlb can be incorporated in composite risk models for aGVHD prediction, with hopes for ultimately allowing for individualized GVHD prophylaxis and potential intervention according to the predicted risk.

Bronchiolitis obliterans syndrome (BOS) after allogeneic hematopoietic cell transplantation (HCT) is associated with high mortality. We hypothesized that inhaled fluticasone, azithromycin, and montelukast (FAM) with a brief steroid pulse could avert progression of new-onset BOS. We tested this in a phase II, single-arm, open-label, multicenter study (NCT01307462). Thirty-six patients were enrolled within 6 months of BOS diagnosis. The primary endpoint was treatment failure, defined as 10% or greater forced expiratory volume in 1 second decline at 3 months. At 3 months, 6% (2 of 36, 95% confidence interval, 1% to 19%) had treatment failure (versus 40% in historical controls, P.001). FAM was well tolerated. Steroid dose was reduced by 50% or more at 3 months in 48% of patients who could be evaluated (n = 27). Patient-reported outcomes at 3 months were statistically significantly improved for Short-Form 36 social functioning score and mental component score, Functional Assessment of Cancer Therapies emotional well-being, and Lee symptom scores in lung, skin, mouth, and the overall summary score compared to enrollment (n = 24). At 6 months, 36% had treatment failure (95% confidence interval, 21% to 54%, n = 13 of 36, with 6 documented failures, 7 missing pulmonary function tests). Overall survival was 97% (95% confidence interval, 84% to 100%) at 6 months. These data suggest that FAM was well tolerated and that treatment with FAM and steroid pulse may halt pulmonary decline in new-onset BOS in the majority of patients and permit reductions in systemic steroid exposure, which collectively may improve quality of life. However, additional treatments are needed for progressive BOS despite FAM.

Several distinct graft-versus-host disease (GVHD)-related syndromes have been defined by the National Institutes of Health Consensus Conference. We enrolled a prospective cohort of 911 hematopoietic cell transplantation (HCT) recipients at 13 centers between March 2011 and May 2014 to evaluate 4 GVHD syndromes: late acute GVHD (aGVHD), chronic GVHD (cGVHD), bronchiolitis obliterans syndrome, and cutaneous sclerosis. The median age at HCT was 53.7 years. The majority of patients received a peripheral blood stem cell transplant (81%) following nonmyeloablative or reduced-intensity conditioning (55%). Pediatric age group and use of bone marrow and umbilical cord blood grafts were underrepresented in our cohort (≤11%). The cumulative incidence of late aGVHD (late onset and recurrent) was 10% at a median of 5.5 months post-HCT, that of cGVHD was 47% at a median of 7.4 months, that of bronchiolitis obliterans was 3% at a median of 12.2 months, and that of cutaneous sclerosis was 8% at a median onset of 14.0 months. Late aGVHD and bronchiolitis obliterans had particularly high nonrelapse mortality of 23% and 32%, respectively, by 2 years after diagnosis. The probability of late aGVHD- and cGVHD-free, relapse-free survival was 38% at 1 year post-HCT and 26% at 2 years post-HCT. This multicenter prospective study confirms the high rate of late aGVHD and cGVHD syndromes and supports the need for continuous close monitoring and development of more effective GVHD treatment strategies to improve HCT success.

Chronic graft-versus-host disease (GVHD) is a pleotropic syndrome that lacks validated methods of measuring response in clinical trials, although several end points have been proposed. To investigate the prognostic significance of these proposed end points, such as the 2005 National Institutes of Health (NIH) response measures, 2014 NIH response measures, clinician-reported response, and patient-reported response, we tested their ability to predict subsequent overall survival (OS), nonrelapse mortality (NRM), and failure-free survival (FFS). Patients (n = 575) were enrolled on a prospective chronic GVHD observational trial. At 6 months, clinician-reported response (P = .004) and 2014 NIH-calculated response (P = .001) correlated with subsequent FFS, and clinician-reported response predicted OS (P = .007). Multivariate models were used to identify changes in organ involvement, laboratory values, and patient-reported outcomes that were associated with long-term outcomes. At 6 months, a change in the 2005 NIH 0 to 3 clinician-reported skin score and 0 to 10 patient-reported itching score predicted subsequent FFS. Change in the Lee skin symptom score and Functional Assessment of Cancer Therapy-Bone Marrow Transplant score predicted subsequent OS. Change in the Lee skin symptom score predicted subsequent NRM. This study provides evidence that clinician-reported response and patient-reported outcomes are predictive of long-term survival. The trial was registered at www.clinicaltrials.gov as #NCT00637689.

BACKGROUND: Allogeneic hematopoietic stem-cell transplantation is the only curative treatment for patients with myelodysplastic syndrome (MDS). The molecular predictors of disease progression after transplantation are unclear. METHODS: We sequenced bone marrow and skin samples from 90 adults with MDS who underwent allogeneic hematopoietic stem-cell transplantation after a myeloablative or reduced-intensity conditioning regimen. We detected mutations before transplantation using enhanced exome sequencing, and we evaluated mutation clearance by using error-corrected sequencing to genotype mutations in bone marrow samples obtained 30 days after transplantation. In this exploratory study, we evaluated the association of a mutation detected after transplantation with disease progression and survival. RESULTS: Sequencing identified at least one validated somatic mutation before transplantation in 86 of 90 patients (96%); 32 of these patients (37%) had at least one mutation with a maximum variant allele frequency of at least 0.5% (equivalent to 1 heterozygous mutant cell in 100 cells) 30 days after transplantation. Patients with disease progression had mutations with a higher maximum variant allele frequency at 30 days than those who did not (median maximum variant allele frequency, 0.9% vs. 0%; P

Familial clustering of myelodysplastic syndromes (MDSs) and acute myeloid leukemia (AML) can be caused by inherited factors. We screened 59 individuals from 17 families with 2 or more biological relatives with MDS/AML for variants in 12 genes with established roles in predisposition to MDS/AML, and identified a pathogenic germ line variant in 5 families (29%). Extending the screen with a panel of 264 genes that are recurrently mutated in de novo AML, we identified rare, nonsynonymous germ line variants in 4 genes, each segregating with MDS/AML in 2 families. Somatic mutations are required for progression to MDS/AML in these familial cases. Using a combination of targeted and exome sequencing of tumor and matched normal samples from 26 familial MDS/AML cases and asymptomatic carriers, we identified recurrent frameshift mutations in the cohesin-associated factor PDS5B, co-occurrence of somatic ASXL1 mutations with germ line GATA2 mutations, and recurrent mutations in other known MDS/AML drivers. Mutations in genes that are recurrently mutated in de novo AML were underrepresented in the familial MDS/AML cases, although the total number of somatic mutations per exome was the same. Lastly, clonal skewing of hematopoiesis was detected in 67% of young, asymptomatic RUNX1 carriers, providing a potential biomarker that could be used for surveillance in these high-risk families.

Decitabine is a hypomethylating agent that irreversibly inhibits DNA methyltransferase I, inducing leukemic differentiation and re-expression of epigenetically silenced putative tumor antigens. We assessed safety and efficacy of decitabine maintenance after allogeneic transplantation for acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Decitabine maintenance may help eradicate minimal residual disease, decrease the incidence of graft-versus-host disease (GVHD), and facilitate a graft-versus-leukemia effect by enhancing the effect of T regulatory lymphocytes. Patients with AML/MDS in complete remission (CR) after allotransplantation started decitabine between day +50 and +100. We investigated 4 decitabine doses in cohorts of 4 patients: 5, 7.5, 10, and 15 mg/m2/day × 5 days every 6 weeks, for a maximum 8 cycles. The maximum tolerated dose (MTD) was defined as the maximum dose at which ≤ 25% of people experience dose-limiting toxicities during the first cycle of treatment. Twenty-four patients were enrolled and 22 were evaluable. All 4 dose levels were completed and no MTD was reached. Overall, decitabine maintenance was well tolerated. Grade 3 and 4 hematological toxicities were experienced by 75% of patients, including all patients treated at the highest dose level. Nine patients completed all 8 cycles and 8 of them remain in CR. Nine patients died from relapse (n = 4), infectious complications (n = 3), and GVHD (n = 2). Most occurrences of acute GVHD were mild and resolved without interruption of treatment; 1 patient died of acute gut GVHD. Decitabine maintenance did not clearly impact the rate of chronic GVHD. Although there was a trend of increased FOXP3 expression, results were not statistically significant. In conclusion, decitabine maintenance is associated with acceptable toxicities when given in the post-allotransplantation setting. Although the MTD was not reached, the dose of 10 mg/m2 for 5 days every 6 weeks appeared to be the optimal dose rather than 15 mg/m2, where most hematological toxicities occurred.

Decitabine has been explored as a reduced‐intensity therapy for older or unfit patients with acute myeloid leukemia (AML). To better understand the risk of infections during decitabine treatment, we retrospectively examined the culture results from each infection‐related serious adverse event that occurred among 85 AML and myelodysplastic syndromes (MDS) patients treated in a prospective clinical study using 10‐day cycles of decitabine at Washington University School of Medicine. Culture results were available for 163 infection‐related complications that occurred in 70 patients: 90 (55.2%) events were culture‐negative, 32 (19.6%) were gram‐positive bacteria, 20 (12.3%) were gram‐negative bacteria, 12 (7.4%) were mixed, 6 (3.7%) were viral, 2 (1.2%) were fungal, and 1 (0.6%) was mycobacterial. Infection‐related mortality occurred in 3/24 (13%) of gram‐negative events, and 0/51 gram‐positive events. On average, nearly one third of patients experienced an infection‐related complication with each cycle, and the incidence did not decrease during later cycles. In summary, in patients receiving 10‐day decitabine, infectious complications are common and may occur during any cycle of therapy. Although febrile events are commonly culture‐negative, gram‐positive infections are the most frequent source of culture‐positive infections, but gram‐negative infections represent a significant risk of mortality in AML and MDS patients treated with decitabine.

Chronic graft-versus-host disease (cGVHD) is a serious complication of allogeneic stem cell transplantation with few effective options available after failure of corticosteroids. B and T cells play a role in the pathophysiology of cGVHD. Ibrutinib inhibits Bruton tyrosine kinase in B cells and interleukin-2–inducible T-cell kinase in T cells. In preclinical models, ibrutinib reduced severity of cGVHD. This multicenter, open-label study evaluated the safety and efficacy of ibrutinib in patients with active cGVHD with inadequate response to corticosteroid-containing therapies. Forty-two patients who had failed 1 to 3 prior treatments received ibrutinib (420 mg) daily until cGVHD progression. The primary efficacy end point was cGVHD response based on 2005 National Institutes of Health criteria. At a median follow-up of 13.9 months, best overall response was 67%; 71% of responders showed a sustained response for ≥20 weeks. Responses were observed across involved organs evaluated. Most patients with multiple cGVHD organ involvement had a multiorgan response. Median corticosteroid dose in responders decreased from 0.29 mg/kg per day at baseline to 0.12 mg/kg per day at week 49; 5 responders discontinued corticosteroids. The most common adverse events were fatigue, diarrhea, muscle spasms, nausea, and bruising. Plasma levels of soluble factors associated with inflammation, fibrosis, and cGVHD significantly decreased over time with ibrutinib. Ibrutinib resulted in clinically meaningful responses with acceptable safety in patients with ≥1 prior treatments for cGVHD. Based on these results, ibrutinib was approved in the United States for treatment of adult patients with cGVHD after failure of 1 or more lines of systemic therapy. This trial was registered at www.clinicaltrials.gov as #NCT02195869.

Hypomethylating agents (HMAs) are standard first line therapy for patients with high risk MDS and older patients with AML. Outcomes for patients who do not respond or progress on HMAs are poor, and there are no standard treatment options for these patients. The interaction between leukemic blasts and the bone marrow microenvironment is thought to play an important role in disease pathogenesis and possibly chemotherapy resistance, so we hypothesized that blocking the CXCL12/CXCR4 axis with CX-01 may improve response rates to azacitidine in patients who have failed HMA therapy. CX-01 is a low molecular weight heparin derivative with minimal anticoagulant activity that binds CXCL12 as well as neutralizes PF4, a negative regulator of megakaryopoiesis. We report updated study results of a single institution a pilot study (NCT02995655) that enrolled patients with HMA-refractory (received 4 or more cycles of HMA without response or disease progression on HMA therapy) AML or MDS (INT-1 or greater). Patients received 7 day continuous infusion of CX-01 (0.25 mg/kg/hr) and azacitidine 75 mg/m2 daily days 1-7, in 28 day cycles. The primary objective of this trial was to assess the overall response rate (ORR). 20 patients were enrolled between May 2017 and February 2018. The median age was 74 years (range 62-88 years) and 35% were female. Nine patients had MDS and 11 had AML, with 7 patients having antecedent MDS and 2 having therapy-related AML. Half of the patients had high risk cytogenetic abnormalities and 3 had TP53 mutations. Patients had a median of 2 prior lines of therapy (range 1-3) with median of 6 prior cycles of HMA therapy (range 4-20). Only 4 patients had a confirmed response to prior HMA therapy. Of the 20 patients that were enrolled, 15 were considered evaluable for response with a bone marrow biopsy after cycle 2. Of the 5 unevaluable patients, 3 were removed from the trial before completing C1 due to transaminitis, discovery of a second primary malignancy, and an elevated PTT on day 2. One patient had grade 5 sepsis during C1, and another withdrew for unrelated reasons. As expected with azacitidine therapy in this patient population, hematologic toxicity was common with 16 instances of grade 3/4 neutropenia/leukopenia, 5 instances of grade 3/4 anemia, and 10 instances of grade 3/4 thrombocytopenia. Other common grade 3/4 adverse events were various infections (20), febrile neutropenia (13), hypertension (10), electrolyte disturbance (9), and transaminitis (3). Mild prolongations in PTT (22) and INR (7) were common, and there was one instance of grade 3 PTT prolongation, two instances of grade 3 epistaxis, and one instance of grade 3 hematuria. The incidences of bleeding were not thought related to CX-01 infusion. The 15 evaluable patients received a median of 3 cycles of CX-01 and azacitidine (range 2-9). Of 15 evaluable patients, there was 1 CR and 3 bone marrow CRs (mCR, with incomplete blood count recovery), 9 stable disease, and 2 progressive disease for an ORR of 27%. Of the 3 patients with a mCR after cycle 2, two had hematologic improvement of their neutrophil and platelet counts, respectively, by the end of cycle 4. A patient with stable disease also had hematologic improvement in platelets. The median OS of evaluable patients was 221 days (95% CI 179 days-not reached) and median overall survival was not significantly different between AML patients at 221 days and MDS patients at 248 days (p = 0.8). In this pilot study we demonstrated the feasibility of treating HMA-refractory AML and MDS with CX-01 and azacitidine. While this study is limited by its small sample size, we observed higher than expected response rate and favorable OS compared to historical controls. Figure Disclosures Cashen: Celgene: Other: Speaker's Bureau; Seattle Genetics: Other: Speaker's Bureau; Novartis: Other: Speaker's Bureau. DiPersio:Incyte: Consultancy, Research Funding; WUGEN: Equity Ownership, Patents & Royalties, Research Funding; Magenta Therapeutics: Equity Ownership; Amphivena Therapeutics: Consultancy, Research Funding; Celgene: Consultancy; RiverVest Venture Partners Arch Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees; Cellworks Group, Inc.: Membership on an entity's Board of Directors or advisory committees; NeoImmune Tech: Research Funding; Macrogenics: Research Funding, Speakers Bureau; Bioline Rx: Research Funding, Speakers Bureau; Karyopharm Therapeutics: Consultancy. Jacoby:Celgene: Speakers Bureau; Novo Nordisk: Consultancy; Jazz Pharma: Membership on an entity's Board of Directors or advisory committees. Uy:Astellas: Consultancy; Pfizer: Consultancy; Curis: Consultancy; GlycoMimetics: Consultancy.

Background Acute graft-versus-host-disease (aGVHD) is one of the leading causes of non-relapse morbidity and mortality following allogeneic hematopoietic cell transplant (allo-HCT). Ruxolitinib (RUX) may be a viable option for patients with steroid-refractory (SR)-aGVHD but limited data currently exists. Methods We performed retrospective chart review to identify patients treated with RUX for S-R-aGVHD 2015-2016 at our center. Primary aGVHD and overlap syndrome were included. Patients who received ≥14 days of RUX were considered evaluable for response assessment. A complete response (CR) was defined as the absence of any symptoms related to aGVHD. A partial response was defined as the improvement of at least one stage in the severity of aGVHD in one organ without deterioration in any other organ. Responses must have maintained for ≥21 days. Results Thirty-six patients were included in the analysis. None were treated on prospective trials of RUX. Demographics are described in Table 1. The median time from allo-HCT to start of RUX was 83 days (range 34-741). The median time from steroid initiation to RUX imitation was 16.5 days (range 2-280) and the median number of prior therapies for S-R-aGVHD was 2 (range 0-5). The majority of patients (72%) were initiated on 5mg BID RUX; 25% were initiated on 10mg BID; 1 patient was initiated on 5mg daily. The median duration of RUX treatment was 21.5 days (range 1-560); 67% received at least 14 days of treatment and were evaluable for response. The overall response rate was 58% with 25% obtaining a CR. RUX was well tolerated; hematologic toxicity was generally mild and not dose limiting and there were no cases of treatment-related mortality. The majority of patients discontinued due to treatment failure or clinical deterioration. Four patients discontinued for toxicity and six for issues in obtaining RUX. Overall, the estimated median overall survival (OS) was 4.9 months (95% CI 2.7-7.0). Of those who were evaluable for response, the median OS was 7.4 months (95% CI UTQ-15.9) for responders compared to 0.9 months (95% CI 0.7-1.1) for non-responders (p Conclusion In this population of high-risk, S-R-aGVHD, RUX is well tolerated and the ORR is 58% (95% CI 38%-78%) in patients receiving ≥14 days of treatment.

The outcome for adult patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) remains poor; new chemotherapy agents with activity against these leukemias are urgently need...

Purpose To identify diagnostic and prognostic markers of chronic graft-versus-host disease (cGVHD), the major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT). Patients and Methods Using a quantitative proteomics approach, we compared pooled plasma samples obtained at matched time points after HCT (median, 103 days) from 35 patients with cGVHD and 18 without cGVHD (data are available via ProteomeXchange with identifier PXD002762). Of 105 proteins showing at least a 1.25-fold difference in expression, 22 were selected on the basis of involvement in relevant pathways and enzyme-linked immunosorbent assay availability. Chemokine (C-X-C motif) ligand 9 (CXCL9) and suppression of tumorigenicity 2 (ST2) also were measured on the basis of previously determined associations with GVHD. Concentrations of the four lead biomarkers were measured at or after diagnosis in plasma from two independent verification cohorts (n = 391) to determine their association with cGVHD. Their prognostic ability when measured at approximately day +100 after HCT was evaluated in plasma of a second verification cohort (n = 172). Results Of 24 proteins measured in the first verification cohort, nine proteins were associated with cGVHD, and only four (ST2, CXCL9, matrix metalloproteinase 3, and osteopontin) were necessary to compose a four-biomarker panel with an area under the receiver operating characteristic curve (AUC) of 0.89 and significant correlation with cGVHD diagnosis, cGVHD severity, and nonrelapse mortality. In a second verification cohort, this panel distinguished patients with cGVHD (AUC, 0.75), and finally, the panel measured at day +100 could predict cGVHD occurring within the next 3 months with an AUC of 0.67 and 0.79 without and with known clinical risk factors, respectively. Conclusion We conclude that the biomarker panel measured at diagnosis or day +100 after HCT may allow patient stratification according to risk of cGVHD.

HLA disparity is not inconsequential in peripheral blood T-replete haploidentical hematopoietic stem cell transplantation

Background: Using error-corrected sequencing with a detection limit of 0.0001, Young et al. (2016) found that 95% of healthy individuals harbor somatic mutations in blood cells in genes associated with leukemia. In addition to increasing the risk of AML (Jaiswal et al. 2014), these clones have recently been associated with cardiac dysfunction (Fuster et al. 2017; Jaiswal et al. 2017). This prompted us to consider the impact of clonal hematopoiesis from healthy donors on outcomes in recipients of allogeneic hematopoietic stem cell transplantation (HSCT). Indeed, donor-derived hematological complications have been anecdotally documented where rare donor clones harboring pathogenic mutations expanded in the recipients following HSCT. As a result, hematopoietic progenitors harboring mutations conferring self-renewal or growth advantages that facilitate preferential engraftment could be unknowingly transferred from donor to recipient (Gibson et al. 2017). Several retrospective studies of secondary hematopoietic malignancies post-HSCT have shown that donor clones harboring mutations in JAK2 and DNMT3A with low variant frequency (VAF) have undergone clonal expansion in the recipients (Yasuda et al. 2014). To date, there has not been a systematic and quantitative study to assess how donor clonal hematopoiesis engrafts and potentially affects the clinical outcome of recipients. In this study, we aim to quantify the spectrum of donor clones that engraft the recipient by longitudinally tracking clonal dynamics in the recipients at three time points post-HSCT. We also aim to compare individual patient outcomes with clonal engraftment. Methods: Error-corrected sequencing (ECS) on 80 genes frequently mutated in AML was performed on 133 isolated peripheral blood leukocytes from 27 allogeneic HSCT recipients at Washington University and the Siteman Cancer Center. Five samples were obtained for each patient which include the matched donor sample from the CIBMTR (n=25) along with pre-transplant, day 30 post-HSCT (D30), day 100 post-HSCT (D100) and one year post-HSCT (D360) for all patients. Independent biological replicates were sequenced for each sample and only the somatic events found in both replicates will be considered true positives using published and validated computational pipelines and thresholds. Results and Conclusions: All D30 and D100 samples harbor clonal mutations (mean 5.67 variants in D30 samples; 5.52 variants in D100 samples) with VAFs ranging from 0.0005 - 0.11. A total of 126 variants are only observed in D30 samples while 122 variants are only observed in D100. Twelve patients have 27 filtered mutations observed in both time points with general increase in VAFs in the later time point. Interestingly, we found SRCAP to be most recurrently mutated in both D30 and D100 samples (48.1% and 33.3%, respectively). This gene has recently been implicated in therapy-related clonal hematopoiesis following cytotoxic treatment (Wong et al. 2018). SRCAP is not frequently observed in clonal hematopoiesis in individuals without preceding hematological disorders or cytotoxic treatments. Therefore, these observed SRCAP variants could either: 1) be present in donors in very low VAFs or 2) arise after transplantation. Analysis of donor sequencing data would provide insight into this. Overall, we find that ECS is a specific and sensitive method for quantitatively characterizing the dynamics of clonal engraftment and proliferation in allogeneic HSCT recipients. In addition, we have found that mutated SRCAP appears to promote clonal engraftment and expansion after conditioning therapy, similar to recent results post-chemotherapy. Future work: Computational analysis of donor and recipient pre-transplant samples along with D360 samples is underway and nearly complete. Correlating ECS results with clinical and demographic (e.g. age and gender of donor and recipient) data is also underway. Disclosures No relevant conflicts of interest to declare.

In 2005, the National Institutes of Health (NIH) Chronic Graft-versus-Host Disease (GVHD) Consensus Response Criteria Working Group recommended several measures to document serial evaluations of chronic GVHD organ involvement. Provisional definitions of complete response, partial response, and progression were proposed for each organ and for overall outcome. Based on publications over the last 9 years, the 2014 Working Group has updated its recommendations for measures and interpretation of organ and overall responses. Major changes include elimination of several clinical parameters from the determination of response, updates to or addition of new organ scales to assess response, and the recognition that progression excludes minimal, clinically insignificant worsening that does not usually warrant a change in therapy. The response definitions have been revised to reflect these changes and are expected to enhance reliability and practical utility of these measures in clinical trials. Clarification is provided about response assessment after the addition of topical or organ-targeted treatment. Ancillary measures are strongly encouraged in clinical trials. Areas suggested for additional research include criteria to identify irreversible organ damage and validation of the modified response criteria, including in the pediatric population.

lips. He did not have diarrhea or pancytopenia. Biopsy of the rash showed lymphocytic interface dermatitis and formation of multiple necrotic keratinocytes with resultant separation at the dermal epidermal junction; findings consistent with GVHD of the skin. When the rash started, the patient was concomitantly on Sulfamethoxazole/ Trimethoprim for pneumocystis jirovecii prophylaxis and was on broad spectrum antibiotics for suspected sepsis; the rash however continued to progress despite stopping these antibiotics two days after the rash appeared. A repeat biopsy was performed to confirm that GVHD is more likely than a drug reaction and this again showed features of GVHD. Short tandem repeat testing to evaluate for chimerism failed to show that in the blood but showed 11% donor cells in the skin biopsy. A diagnosis of GVHD was made, IV steroids were starteddfive days after the rash developeddwith a methylprednisolone bolus followed by 1mg/kg; this achieved mild improvement. Etanercept was added after four days of steroids (25 mg subcutaneously twice weekly for 8 doses) with further improvement. Conclusions: GVHD post solid organ transplant as a diagnosis is often missed, because the presenting signs and symptoms are nonspecific and the condition is rare. Prognosis is in general poor and complications of pancytopenia usually lead to the high mortality associated with this disease. There are no guidelines as to how to treat this condition but careful intensification (or withdrawal) of immunosupression can potentially lead to successful control of this disease process. We treated this patient with parenteral steroids and added etanercept with a favorable outcome.

7044 Background: There is no standard treatment for patients with leukemia who relapse after allogeneic stem cell transplant (HCT). A second HCT (HCT2) may be the only possibly curable option; however, this is performed in few patients. We hypothesized that patient and transplant characteristics, such as donor source will affect outcomes. Methods: We retrospectively evaluated adult patients who received a HCT2 for relapsed leukemia or MDS at a single institution between 2000-2016. 85 patients underwent a HCT2 with an unmanipulated graft from a matched related (MRD, n = 21), matched unrelated (MUD, n = 40), or haploidentical (haplo, n = 24) donor, preceded by either a reduced intensity (RIC) or myeloablative conditioning (MAC) regimen. Results: The median age at HCT2 was 50 yrs and the median time between transplants was 448 days. Patients had relapsed AML (n = 62), ALL (n = 12), and MDS (n = 10). The median length of follow up for survivors was 22.3 months (range 3.9-131) with 20 patients alive in June 2016. 65 patients died; 32 from relapse, 21 from infection, 7 from GvHD, and 5 from organ failure. 1-year OS from HCT2 was 38.6%. For patients with MRD, MUD, haplo donors, 1 year OS was 52.3%, 33.3%, and 34.6% (p = 0.72). 1-year DFS in the entire cohort, MRD, MUD, and haplo groups was 26.4%, 14.3%, 34.8%, and 25.3% (p = 0.45). 1-year TRM was 36.2% and not different across these groups (p = 0.80). Univariate analyses of OS, DFS, and TRM based on patient, disease, and transplant characteristics showed an association with RIC and worse OS and DFS (HR 2.0, 95% CI 1.2-3.3; and HR 1.9, 1.2-3.1). Having > 1 year between transplants was associated with lower TRM (HR 0.38, 0.19-0.77). Traditional risk factors like age, presence of active disease at HCT2, shorter time between transplants, and using the same donor from the first HCT were not otherwise significantly associated with OS, DFS, or TRM. Conclusions: Outcomes after HCT2 did not differ based on donor source. MAC is associated with better OS relative to RIC (1yr OS 51% vs 23%, p < 0.01), DFS (1yr DFS 37% vs 12%, p < 0.01), with similar TRM (1yr TRM 30% vs 47%, p = 0.12). Based on these data, serious consideration is necessary before using RIC regimens for HCT2 in patients with relapsed leukemia.

Background: Chronic GVHD (cGVHD) is a serious complication of allogeneic stem cell transplantation. Effective therapy for patients (pts) with cGVHD who fail corticosteroids remains an unmet medical need. Both B and T cells play a role in the pathophysiology of cGVHD. In preclinical models, ibrutinib (ibr) reduced the severity of cGVHD through its inhibition of Bruton's tyrosine kinase (BTK) and interleukin-2-inducible T-cell kinase (ITK) (Dubovsky, J Clin Invest 2014). Ibr has recently been granted a breakthrough therapy designation (BTD) for cGVHD after failure of 1 or more lines of systemic therapy. The request for a BTD was supported by early data from a phase 2 study that evaluated the efficacy and safety of ibr in pts with cGVHD who are in need of additional therapy. The final results of this same study are presented here. Methods: Pts who had received ≤3 prior regimens for cGVHD and had either >25% body surface area erythematous rash or a National Institutes of Health (NIH) mouth score >4 were treated with daily ibr (420 mg) until cGVHD progression or unacceptable toxicity. The primary end point was cGVHD response based on the 2005 NIH consensus response criteria. Secondary end points included rate of sustained response, change in Lee cGVHD symptom scale, changes in corticosteroid requirement over time, and safety end points. The effects of ibr on lymphoid and myeloid cell signaling pathways, and phenotype along with plasma cytokines and chemokines were evaluated. Results: A recommended phase-2 dose of 420 mg was identified in phase 1b (n=6) with no dose-limiting toxicities reported. Of 42 pts treated with ibr, median age was 56 y (range, 19-74). Median duration of cGVHD before study entry was 13.7 mo (range, 1.1-63.2). Median number of prior regimens was 2 (range, 1-3). At a median follow-up of 13.9 mo, overall response rate (ORR) was 67% (28/42 pts; 9 [21%] CR, 19 [45%] PR), with 20/28 (71%) and 12/25 (48%) responders showing a sustained response of ≥20 and ≥32 weeks, respectively (Figure 1). Overall, 21 responders (75%) had corticosteroid doses 3 pts were pneumonia (n=6), fatigue (n=5), and diarrhea (n=4). Serious AEs (SAEs) occurred in 22 pts (52%); grade ≥3 SAEs reported in 17 pts (40%) included pneumonia (n=5), septic shock (n=2), and pyrexia (n=2). Two fatal events (multilobular pneumonia and bronchopulmonary aspergillosis) were reported. Five pts discontinued therapy for progressive cGVHD and 14 for AEs including fatigue (n=3) and pneumonia (n=2). Twelve pts (29%) continued ibr; their treatment duration ranges from 5.6-24.9 mo. Conclusions: With an ORR of 67% and a sustained response rate of ≥20 weeks of 71%, treatment with ibr resulted in clinically meaningful and durable responses in pts who failed at least 1 prior treatment for cGVHD. Most responders were able to reduce steroid dose to an acceptable minimal level. Biomarker changes support an effect of ibr on immune cell subsets in pts with cGVHD. Reported AEs are consistent with those for ibr in B-cell malignancies and pts with cGVHD. Observed response rates in this pretreated, high-risk population support further study of ibr for frontline treatment of cGVHD. Disclosures Miklos: Pharmacyclics, LLC, an AbbVie Company: Consultancy, Other: Travel, Accommodations, and Expenses, Research Funding; Kite Pharma: Research Funding; Roche: Research Funding; Novartis: Research Funding; Sanofi Oncology: Other: Travel, Accommodations, and Expenses. Cutler:Insys: Consultancy; Seattle Genetics: Consultancy; Regimmunie: Consultancy; Incyte: Consultancy. Arora:Takeda Oncology: Consultancy; Pharmacyclics, LLC, an AbbVie Company: Research Funding. Waller:Cerus: Equity Ownership; Chimerix: Equity Ownership; Cambium Medical Technologies: Equity Ownership, Other: Other relationship indicated, Patents & Royalties; Novartis: Consultancy, Honoraria, Research Funding; Helocyte: Consultancy. Jagasia:Theracos: Consultancy, Research Funding; Janssen: Consultancy, Research Funding. Flowers:Pharmacyclics, LLC, an AbbVie Company: Research Funding. Logan:Amgen: Consultancy; Jazz: Consultancy; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Research Funding; Astellas: Research Funding; Novartis: Research Funding. Nakamura:Seattle Genetics: Consultancy; Amgen: Consultancy. Blazar:Tobira Therapeutics: Consultancy; Vulcan CApital: Consultancy; Idera Pharma: Consultancy; Sidley Austin LLP: Consultancy; Merck Serono: Consultancy; Fate Therapeutics: Consultancy; Merck, Sharpe & Dohme Corp: Consultancy; Bristol-Myers Squibb: Consultancy; Kadmon Pharmaceuticals Inc: Consultancy, Research Funding; Kymab: Consultancy; Five Prime Therapeutics: Consultancy; Vitae Pharmaceuticals, Inc.: Consultancy; Flx Bio: Consultancy; No Company: Patents & Royalties: no company. Li:Pharmacyclics, LLC, an AbbVie Company: Employment; AbbVie: Equity Ownership. Lal:AbbVie: Equity Ownership; Pharmacyclics, LLC, an AbbVie Company: Employment; Infinity: Equity Ownership; Clovis: Equity Ownership; Reviva Pharmaceuticals: Equity Ownership; The Permanente Medical Group: Employment, Equity Ownership; Gilead Sciences: Employment, Equity Ownership. Dubovsky:Pharmacyclics, LLC, an AbbVie Company: Employment; AbbVie: Equity Ownership. James:Pharmacyclics, LLC, an AbbVie Company: Employment; AbbVie: Equity Ownership. Styles:Pharmacyclics, LLC, an AbbVie Company: Employment; AbbVie: Equity Ownership. Jaglowski:Pharmacyclics, LLC, an AbbVie Company: Consultancy, Research Funding.

Chronic graft-versus-host disease (cGvHD) is the leading cause of late non-relapse morbidity and mortality after allogeneic HCT. There is no standard therapy for steroid-refractory disease. Thalidomide, an immune-modulating drug, showed some activity in advanced sclerotic cGvHD but was difficult to tolerate at active doses. Pomalidomide (Pom) is related to thalidomide, but with higher potency and a more favorable toxicity profile. A pilot study suggested Pom was effective in cGvHD, however doses >2 mg/day were poorly tolerated (Pusic et al, BMT, 2016;51:612). In this randomized phase 2 trial we aimed to determine the optimal dose and to evaluate the efficacy of Pom (NCT01688466). Methods: Subjects were randomized to a low-(LD) 0.5 mg/d or a high-dose (HD) cohort with a starting dose 0.5 mg/d increasing to 2 mg/d over 6 w. Dose reductions for ≥Grade-3 non-hematologic or ≥Grade-4 hematologic adverse events (AEs) on HD-cohort were allowed. There was no crossover. Concomitant stable or tapering systemic therapy for cGvHD was permitted. Venous thrombo-embolism prophylaxis was ASA 325 mg/d. Response was assessed by 2005 NIH response criteria (Filipovich AH et al, 2005;11:945). Primary endpoint was overall response rate (ORR) at 6 mo. Responders could continue at their assigned dose for 6 more mo. Secondary endpoints were safety, PKs and immune studies. The cohort with the higher response rate would be chosen for further evaluation, or if a tie, the LD arm would be favored. Results: From 02/2013 to 05/2016, 32 subjects were randomized (LD, n=16; HD, n=16). Median age was 48 y (range, 20-73 y), 21 (66%) male, median time from transplant 4.1 y (1.5-9.7 y), median time from onset of cGvHD 3.2 y (0.6-8.5 y). Thirty subjects had Global Score Severe. The most severely affected tissues/organs were skin (n=30, 94%), eyes (n=6, 19%) and joints/fascia (n=11, 34%). Most had ≥ 20% body surface area deep sclerosis (n=24, 75%). Pts had received a median 5 (2-9) prior systemic therapies. Baseline characteristics were similar in the two cohorts. Peak/trough levels of Pom were measured at 0.5, 1, 1.5, 2 mg doses and CMax increased in a dose-proportional manner (r2=0.9997), suggesting linear PKs. The most frequent AEs were lymphopenia, infection and fatigue (Table). Six subjects in the HD cohort were dose reduced to 1.5 mg/d because of fatigue (n=3), elevated ALT/AST (n=1), bradycardia (n=1) and neutropenia (n=1), and 2 subjects reduced further to 1 mg/d. There was 1 death in the LD cohort from pneumonia. 9 subjects discontinued ≤ 6 mo because of AEs (n=5) or withdrawal (n=4). More subjects in the HD cohort discontinued early; (HD, n=7; LD, n=2). ORR at 6 mo in an intent-to-treat analysis was 47% (n=15, PR). ORR increased to 71% in 21 evaluable subjects. ORR in LD and HD were similar 50% (n=8/16) and 44% (n=7/16) respectively. 9 evaluable subjects (43%) had improvement in NIH joint/fascia scores (p=0.004) and median decrease of 10% body surface area involvement with cutaneous cGvHD (p=0.0027 by Wilcoxon signed rank test). Among the NIH response measures, the strongest association with response was the 11-point health care provider severity, median improvement 2 points (p=0.0055 by Jonckheere-Terpstra test), as well as improvements in restrictions in range of motion at elbow (p=0.023) and wrist (p=0.032). 67% (10/15) of the responders also reported clinically significant improvements in self-reported cGvHD symptom bother (Lee scale) and SF-36 physical component summary scores (p Median decreases in prednisone dose compared to baseline were 13% (0-67) at 6 mo and 63% (17-81) at 12 mo of Pom. More subjects completed the planned 12 mo of Pom in the LD- vs. HD- cohort (7 vs. 4). After 12 mo of Pom, 3 subjects in the LD arm had progressed cGvHD. Two of those subjects had SD after restarting Pom. A 3rd responded and continued Pom for an additional 12 mo. Conclusion: This phase 2, randomized trial demonstrates that Pom is an effective salvage therapy for persons with severe, corticosteroid-refractory cGvHD, including sclerotic skin disease. Response rates were similar with 0.5 and 2 mg/d but there were more early discontinuations with 2 mg/d. Organs with most improvement were skin and joints suggesting an anti-fibrotic effect. Pom is a promising new therapy for refractory cGvHD. As HD Pom was less well tolerated without a significant improvement in response, Pom 0.5 mg/d is recommended. Table. Table. Disclosures No relevant conflicts of interest to declare.

Introduction: The introduction of reduced intensity conditioning (RIC) regimens, associated with less NRM, has significantly broadened transplant eligibility to older patients. However, graft-versus-host disease (GVHD) continues to be a major problem, even with RIC allo-HCTs. At our institution, we have been routinely adding mycophenolate mofetil (MMF) to the standard methotrexate (MTX) plus Tacrolimus combination in the majority of RIC allo-HCT recipients from unrelated donors. However, there is a paucity of data on whether this approach further decreases GVHD rates without increasing NRM and risk of relapse. To answer these questions, we retrospectively analyzed data from 177 patients who received MMF, MTX and Tacrolimus (MMF + Tac/MTX) as part of their GVHD prophylaxis and compared their outcomes to those of 117 patients who received MTX and Tacrolimus alone (Tac/MTX). Patients and methods: The study included a total of 294 consecutive patients who underwent RIC allo-HCT at Washington University Medical Center between January 2006 and December 2013. The data was analyzed for patients who received GVHD prophylaxis with either tacrolimus/methotrexate (Tac/MTX) or tacrolimus/mycophenolate mofetil/methotrexate (MMF+Tac/MTX). Cumulative incidence of relapse was estimated treating death in remission as competing risk event. Cumulative incidence of NRM was calculated considering death in relapse as competing risk event. Univariate analysis was performed to evaluate variables, and multivariate Cox models with a backward selection procedure were done to assess whether GVHD prophylaxis was an independent predictor after adjusting other factors significant in the univariate analysis. All analyses were two-sided, and significance was set at a p-value of 0.05. Statistical analyses were performed using library cmprsk in statistical package R for competing risk analysis and SAS 9.4 (SAS Institutes, Cary, NC) for all other analyses. Results: 177 patients (60.2%) received MMF+Tac/MTX whereas 117 patients (39.8%) received Tac/MTX. Median age was 61 years in the MMF+Tac/MTX group and 58 years in the Tac/MTX group, and the most common diagnosis was AML(31%) followed by NHL (26%) and MDS (19%) in the MMF+Tac/MTX group vs. AML (45%) followed by MDS (14%) and NHL (13%) in the Tac/MTX group. There were more transplants from unrelated and mismatched donors, higher intermediate ASMBT RFI risk group patients and more frequent use of conditioning with Flu/Bu/Thymo regimen in the MMF+Tac/MTX cohort. In particular 160 (90.4%) patients in MMF+Tac/MTX group received thymoglobulin as part of their conditioning, compared to 64 (54.7%) patients in the Tac/MTX group (p < 0.001). The cumulative incidence of grade 2-4 aGVHD at day 100 was 31.0% in the MMF+Tac/MTX group vs. 36.2% in the Tac/MTX group (p=0.191) while as grade 3-4 aGVHD at day 100 and 1 year were 16.8% and 25.9% in the Tac/MTX group compared to 8.0% and 12.4% in the MMF+Tac/MTX group, respectively (p=0.010). However, after adjusting for the thymoglobin use there was no significant difference in the incidence of grade 3-4 aGVHD in these two groups (p=0.129). To eliminate the confounding effect of thymoglobulin, we performed a subgroup analysis of patients without thymoglobulin. Given the small number of samples (n=17 in MMF+Tac/MTX and n=53 in Tac/MTX), propensity score matching was used and the results again showed no significant difference in severe aGVHD between two groups (p=0.219). The incidence of cGVHD at 1 year was 15.3% and 21.6% in MMF+Tac/MTX and Tac/MTX, respectively (p=0.645). Although patients in the MMF+Tac/MTX group had more unfavorable disease risk, the cumulative incidence of relapse at 3 years was not significantly different: 40.8% in the MMF+Tac/MTX group and 39.8% in the Tac/MTX group (p=0.941). 5-year OS was 33.7% in the MMF+Tac/MTX group, compared to 35.1% in the Tac/MTX group (p=0.769). Conclusion: Here we report transplant outcomes of RIC allo-HCT patients who received MMF in addition to Tac/MTX for GVHD prophylaxis. Interestingly we did not see any increase in NRM or relapse rates with additional immune-suppression from adding MMF in these patients. However, addition of MMF to the Tac/MTX regimen did not result in any significant improvement in acute or chronic GVHD outcomes in our patients. Based on these results we do not recommend adding MMF to Tac/MTX regimen for GVHD prophylaxis in RIC allo-HCT patients. Disclosures Uy: Novartis: Research Funding. Schroeder:Incyte: Consultancy; Celgene: Other: Azacitidine provided for this trial by Celgene. Abboud:Pfizer: Research Funding; Merck: Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Novartis: Research Funding; Teva Pharmaceuticals: Research Funding; Gerson Lehman Group: Consultancy. Cashen:Celgene: Speakers Bureau.

Background The negative impact of acute graft-versus-host disease (GvHD) on morbidity and mortality after allogeneic transplant is significant; thus, finding a means to harness the beneficial Graft versus tumor effect (GVT) while reducing or eliminating GvHD is a major goal of transplant trials. Alterations in immune subsets present after transplant can work to suppress allo-reactive T-cell responses by increasing regulatory T-cells and suppressing allo-reactive T-cell proliferation. Azacitidine (AZA) treatment in pre-clincal models resulted in an increase in regulatory T-cells, a decrease in allo-reactive T-cell proliferation and prevention of acute GvHD while preserving GVT effects. (Choi et al. Blood 2010). Based on these results a phase I/II study was designed to test the safety and efficacy of AZA administered shortly after transplant for the prevention/prophylaxis of acute GvHD and relapse in subjects receiving transplants from matched unrelated stem cell donors. We report the results for the Phase I portion of this trial. Methods Patients with hematologic malignancies in remission age 18 - 70 were eligible. Myeloablative or reduced intensity conditioning without antithymocyte globulin was used. All recipients were required to receive at least 2 x 106 CD34/kg and have at least 1 x 106 CD34/kg cryopreserved as back up in case of primary graft failure. AZA was administered intravenously on day +7 for five consecutive days and repeated every 28 days for a total of 4 cycles after allogeneic transplant from a 10/10 HLA matched unrelated donor. Standard GvHD prophylaxis with mini-methotrexate and tacrolimus was given. A Phase I, 3+3 dose escalation design of 4 cohorts (AZA dose levels 15, 30, 37.5, and 45 mg/m2) was used to determine toxicity and recommended phase II dose. The primary outcome for phase II is the rate of grade II - IV acute GvHD at day 180 after transplant. Results We have transplanted 16 subjects on trial, 15 have received study drug. Recipient characteristics include: median age 57, 67% male, and diagnoses of AML in CR (9), ALL in CR (2), or MDS (4). One DLT was observed in the final cohort of 6 subjects. The DLT experienced in the final cohort was primary graft failure. The subject had developed Clostridium difficile colitis during conditioning and fungemia shortly after transplant. A total CD34 dose of 2 x 106/kg was infused after myeloablative conditioning of Busulfan and Cytoxan. The subject received the cryopreserved back up donor leukocyte infusion at day +28 but died at day 29 of sepsis without evidence of neutrophil engraftment. Contributing causes to the DLT were thought to be the CD34 dose infused, sepsis, severe colitis and possibly AZA administration. For the remainder of subjects treated in phase I the median CD34 dose infused was 5 x 106/kg (range 2 - 5), median ANC engraftment was 14 days (range 10 - 22 days). Median platelet engraftment was 22 days (range 14 - 70). No grade III/IV acute GvHD has been observed. Grades 1 and 2 skin and gut GvHD have been observed, and all cases have responded to steroids except one case of steroid refractory GvHD in cohort 1 (15mg/m2 AZA). At the recommended phase 2 dose of 45mg/m2 AZA, 3 cases of skin GvHD were observed occurring just prior to or at the time of cycle 2 of treatment. All responded to steroids. With a median follow up of 233 days (range 29 - 784), only 2 subjects have relapsed and 11 (73%) remain alive. The most common non-hematologic grade 3 or 4 AEs were gastrointestinal toxicity (mucositis, nausea and diarrhea), electrolyte abnormalities, and infections. In conclusion, AZA can be given safely starting at day +7 after MUD transplant up to a dose of 45mg/m2 tested. Phase II is currently enrolling subjects. Because of the DLT experienced in phase I, the infused CD34 dose will be increased to a minimum of 4 x 106 CD34/kg with 1 x 106 CD34/kg cryopreserved in backup. Correlative studies from banked Phase I biospecimens evaluating dynamics of regulatory T-cells, T-cell subsets and methylation before and after treatment are being analyzed and will be reported. Disclosures Schroeder: Incyte: Consultancy; Celgene: Other: Azacitidine provided for this trial by Celgene. Off Label Use: Azacitidine for GVHD prophylaxis. Abboud:Gerson Lehman Group: Consultancy; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Novartis: Research Funding; Pfizer: Research Funding; Merck: Research Funding; Teva Pharmaceuticals: Research Funding. Vij:Onyx: Consultancy, Honoraria, Research Funding, Speakers Bureau; Millennium: Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; BMS: Consultancy; Takeda: Consultancy, Research Funding; Novartis: Consultancy; Sanofi: Consultancy; Janssen: Consultancy; Merck: Consultancy.

To determine how AML subclonal architecture changes during decitabine treatment, and whether specific mutations might correlate with sensitivity vs. resistance to decitabine, we performed exome sequencing at multiple time points during single agent decitabine therapy. We enrolled 69 patients with either AML (age ≥ 60, or with relapsed/refractory disease, N = 45) or MDS (N = 24) on a phase I clinical trial. All subjects were treated with decitabine 20 mg/m2 on days 1-10 of 28 day cycles. With a median follow-up of 13.7 months, the intention to treat clinical response (complete remission with or without complete count recovery: CR/CRi) is 40%, with survival correlating with response (median survival - CR/CRi: 583 days; partial response/stable disease (PR/SD): 260 days; progressive disease (PD) or failure to complete cycle 1: 36 days, p < 0.0001). We performed exome sequencing on unfractionated bone marrow cells at diagnosis (day 0), cycle 1 day 10, cycle 1 day 28, cycle 2 day 28, and, when possible, during remission and at clinical relapse/progression. We have completed sequencing analysis for the first 34 cases (outcomes: 5 CR, 15 CRi, 3 PR, 8 SD, and 3 PD). Several important themes have emerged, as follows: 1) We correlated mutation status at diagnosis with clinical response. All six patients with TP53 mutations obtained clinical CR or CRi, and exome analysis demonstrated near complete elimination of the TP53- associated founding clones by the end of cycle 2 (p < 0.03). Long-term outcomes were similar in these patients compared with other patients who achieved CR/CRi: four patients relapsed after 8, 9, 10, or 17 cycles; 1 patient is doing well post-transplant; and one patient died of an infectious complication after cycle 2. No other mutations were significantly associated with clinical response or with consistent mutation clearance. 2) We observed a reduction in blast counts, which preceded mutation elimination in fourteen cases with CR, CRi or PR. This suggests that decitabine may induce morphological blast differentiation in vivo prior to mutation elimination. 3) In eight of nine cases with a clinical response followed by relapse, clinical progression was associated with expansion of a pre-existing subclone. We have not yet observed any recurrent mutations that reliably predict whether a subclone will contribute to relapse. Intriguingly, in two of these cases, the relapse-associated subclone was detectable at diagnosis and was eliminated more slowly than the founding clone mutations, suggesting that this subclone harbored intrinsic decitabine-resistance. 4) Complete remission can occur with concomitant non-malignant, clonal hematopoiesis. In three cases with a CR, a new clonal population was selected for during the remission. In two of these cases, there were no shared mutations between the founding clone and the emergent, non-malignant, clonal hematopoiesis, suggesting that these clones were unrelated. 5) Mutational architecture is generally stable, but differential chemo-sensitivity can be detected even between subclones in the same patient. In ten cases with PR or SD, we observed minimal shifts within the mutational burden over the course of eight weeks, suggesting that "clonal drift" is a relatively slow process. However, in four cases with SD, what appeared clinically to be simple persistent disease was in fact a dynamic elimination of one subclone, and its replacement by a different subclone. Similarly, in three cases with CRi, we observed rapid clearance of a subclone with slower clearance of the founding clone, again suggesting differential chemo-sensitivity among subclones. 6) Finally, we correlated pharmacologic markers with clinical outcomes. We observed no correlation between steady-state plasma decitabine levels and clinical responses. Using Illumina 450k methylation arrays, we observed a correlation between response and the extent of decitabine-induced hypomethylation in total bone marrow cells that persisted on cycle 1 day 28 (p < 0.01), but not on cycle 1 day 10 (p < 0.1). In summary, these data reveal that response to decitabine is associated with morphologic blast clearance before mutations are eliminated, that relapse is associated with subclonal outgrowth that may be identified early in the treatment course, and that TP53 mutations may be predictive of rapid clinical responses, although, like most responses to decitabine, these are not necessarily durable. Disclosures Off Label Use: Decitabine treatment of AML.. Uy:Novartis: Research Funding. Oh:CTI Biopharma: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees. Abboud:Novartis: Research Funding; Gerson Lehman Group: Consultancy; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Pfizer: Research Funding; Merck: Research Funding; Teva Pharmaceuticals: Research Funding. Cashen:Celgene: Speakers Bureau. Schroeder:Celgene: Other: Azacitidine provided for this trial by Celgene; Incyte: Consultancy. Jacoby:Sunesis: Research Funding; Novo Nordisk: Consultancy.

Background: Over the past two decades, peripheral blood stem cells (PBSC) have surpassed bone marrow as the preferred graft source for adult allogeneic transplantation due to its more rapid engraftment and potentially better graft-vs-tumor effects, and because PBSC collection is much less invasive for the donor. The optimal CD34+ PBSC dose is ≥ 4.0x106cells/kg, but doses ≥ 8.0x106cells/kg are suggested by some for reduced-intensity conditioning and haploidentical transplants. There is no established minimum CD34+ PBSC dose, but doses below 2.0x106cells/kg have been associated with a higher risk of engraftment delay and failure. There is significant inter-donor variability in the ability to mobilize PBSCs. Several factors have been identified as predictors of PBSC mobilization in healthy donors including: gender, age, weight, body mass index (BMI), and blood counts before and after mobilization. The impact of the donor’s comorbidities on mobilization is currently unknown. Patients/Methods: We performed retrospective chart review of 488 consecutive adult patients who underwent apheresis for allogeneic stem cell donation at Washington University School of Medicine from 2006 through 2013. Patients who received any collection regimen other than 10mcg/kg of G-CSF daily with 20 liters (+/-10%) apheresis on Day 5 were excluded. Patients who had undergone a previous apheresis for stem cell donation were excluded. Univariate analysis was performed to identify predictors of CD34+ PBSC collection in a single apheresis. Variables analyzed were: gender; age; weight; BMI; donor-to-recipient weight ratio; pre and post-mobilization blood counts (white blood count [WBC], hematocrit, platelets, neutrophils, lymphocytes, and monocytes); pre-mobilization glucose and triglyceride levels; post-mobilization peripheral blood (PB) CD34+count; and medical history significant for hypertension, hyperlipidemia, or diabetes mellitus. Subsequently, a linear regression multivariate analysis was performed with all variables found to be significant in the univariate analysis. 2-tailed tests for significance were used throughout the analysis. Results: 304 patients met the eligibility criteria for analysis. The median age was 53 years (range 18-76), 90% were Caucasian, and 50% were male. The median number of CD34+ cells collected was 7.4 x106/kg (range 0.8-27.1). 97% (295) collected ≥ 2.0x106 CD34+cells/kg, 81% (247) collected ≥ 4.0x106 CD34+cells/kg, and 44% (134) collected ≥ 8.0x106 CD34+ cells/kg. Post-mobilization PB CD34+ count (r= 0.841, p Conclusion: After one apheresis, the majority (81%) of donors collected ≥ 4.0x106 CD34+ cells/kg, the optimal number of CD34+ cells for standard allogeneic transplant, but only 44% were able to collect ≥ 8.0x106, the suggested number of CD34+ cells for reduced-intensity or haploidentical transplants. As these reduced-intensity and haploidentical transplants increase in frequency, the need for more accurate predictors of CD34+cell collection will also increase. Donor-to-weight ratio could be a useful tool to stratify potential donors for reduced-intensity and haploidentical transplants. In this study, 63% of donors with a donor-to-recipient weight ratio > 1.0 collected ≥ 8.0x106 CD34+cells/kg, while only 20% of donors with a donor-to-recipient weight ratio ≤ 1.0 did. While gender, weight, and BMI have previously been reported as predictors for CD34+ collection, they potentially were just surrogates for donor-to-recipient weight ratio. Disclosures No relevant conflicts of interest to declare.