Deeg, H. Joachim

Introduction: Myelodysplastic syndromes (MDS) are a heterogenous group of blood disorders defined by peripheral cytopenia(s), bone marrow failure, morphological dysplasia, and risk of progression. To understand the genetic, epigenetic and biological factors associated with the initiation and progression of MDS, NHLBI created the National MDS Study (NCT02775383). This is a prospective cohort study conducted at 92 community hospitals and 29 academic centers enrolling patients undergoing diagnostic work up for suspected MDS or MDS/myeloproliferative neoplasm (MPN) overlap syndrome. Eligible patients have yet to receive any therapy directed at their cytopenias. Previously untreated cytopenic participants underwent centralized histopathology and data review at the time of enrollment for assignment into distinct subcategories: MDS, MDS/MPN overlap, AML, and Other. Targeted exon sequencing of 96 genes was performed using marrow specimens from the first 300 consecutive individuals in the study. Here we report the genetic mutations for this cohort. Methods: NovaSeq 6000 was used for deep sequencing at a mean coverage of 1,286X and mean breadth (bases covered at ≥100X) of 99.8%. Reads were aligned against build GRCh38 using BWA-MEM, and VarScan2 was used to detect SNVs and INDELS. Variants were filtered for those with an allele base quality of >25 in combination with rule-based and manual review criteria. Subjects in the Other category without an identified malignancy were considered clonal cytopenias of undetermined significance (CCUS) when a mutation or a clonal cytogenetic change was present. Fisher's exact and Wilcoxon rank sum tests in combination with Bonferroni correction were applied to compare groups. Results : A total of 350 putative nonsynonymous pathogenic variants in 36 genes with an allele frequency of >.05 were identified across 150 patients (50%). At least one variant was noted in the following proportion of individuals: 61/72 (85%) with MDS, 13/13 (100%) with MDS/MPN, 15/17 (88%) with AML, and 61/198 (31%) in the Other category, of which 48 were CCUS and 13 were other cancers. Two CCUS patients only had a cytogenetic abnormality. Table 1 shows the distribution of variants in each subcategory of patients for the most commonly mutated genes in our cohort of 300 subjects. Mutations in these genes were enriched in specific groups: SF3B1, STAG2,TP53, and ASXL1 in MDS; TET2 in MDS/MPN; and IDH2 and TP53 in AML (one-sided p<0.0012). None were enriched in the Other group. Within the CCUS subset, 21 genes were mutated, with 37 of 50 (74%) patients having a mutation in TET2, ASXL1, SRSF2, SF3B1, or DNMT3A. The heatmap presented in Figure 1 summarizes variants by subject and allele frequency. Pair-wise comparisons of baseline characteristics of subjects between MDS, MDS/MPN, AML, or CCUS groups revealed no significant differences for age or sex. The CCUS group had significantly higher hemoglobins than the MDS group with median hemoglobin levels of 11.35 and 9.40 g/dL, respectively (p<0.0084). AML had significantly lower platelets compared to all other groups (median of 53 vs. > 110x109/L , respectively, p<0.0084). All groups significantly differed in their median ANC with AML having the lowest (0.8x109/L), followed by MDS (1.5x109/L), CCUS (2.45x109/L), and MDS/MPN overlap (5.95x109/L) (p<0.0084). There was no difference in the median number of variants per patient between groups or correlation with age (rs=0.11, p=0.18). The maximum variant allele frequency (maxVAF) per patient was highest in the MDS/MPN group (median = 0.42, range = 0.38-0.91) and lowest in the CCUS group (median = 0.37, range =0.06-0.98) with the MDS/MPN group having a significantly higher maxVAF compared to the MDS and the CCUS groups (p<0.0084). The proportions of subjects with mutations was similar for those who had abnormal (92% [34/37]) and normal (91% [80/88]) cytogenetics. Conclusions: Incorporation of gene-panel sequencing in the comprehensive evaluation of 300 adult cytopenic patients identified half of the cohort with potentially pathogenic variants. Ultimately, a diagnosis of CCUS was possible in 48 of 183 subjects (26%) not diagnosed with MDS, MDS/MPN overlap syndrome, AML, other cancers or clonal cytogenetics. This study continues to serially bank samples from patients with CCUS, in addition to MDS, MDS/MPN, and ICUS, with the goal to better understand the natural history of these diseases and their progression. Disclosures Lindsley: Jazz Pharmaceuticals: Research Funding; Takeda Pharmaceuticals: Consultancy; Medlmmune: Research Funding. Bejar:Celgene: Consultancy; Takeda Pharmaceuticals: Research Funding; AbbVie/Genentech: Consultancy, Honoraria; Astex/Otsuka: Consultancy; Modus Outcomes: Consultancy; Daiichi-Sankyo: Consultancy. Al Baghdadi:Celgene: Consultancy, Honoraria; Heron: Consultancy, Honoraria; Tracon: Equity Ownership; Epizyme: Equity Ownership; Bristol Myer Squibb: Consultancy, Honoraria; Sunesis: Equity Ownership; Portola: Equity Ownership; Heron therapeutics: Equity Ownership; Cardinal health: Consultancy, Honoraria; Bristol Myer Squibb: Equity Ownership; Celgene: Equity Ownership; Spectrum pharmaceutical: Equity Ownership; Astrazeneca: Equity Ownership; Seattle genetics: Equity Ownership; Roche: Consultancy, Honoraria. DeZern:Astex Pharmaceuticals, Inc.: Consultancy; Celgene: Consultancy. Foran:Agios: Honoraria, Research Funding. Gore:Celgene Corporation: Consultancy, Research Funding. Komrokji:DSI: Consultancy; Agios: Consultancy; Novartis: Speakers Bureau; JAZZ: Speakers Bureau; pfizer: Consultancy; celgene: Consultancy; Incyte: Consultancy; JAZZ: Consultancy. Maciejewski:Alexion: Consultancy; Novartis: Consultancy. Starczynowski:Kurome Therapeutics: Consultancy. Sekeres:Millenium: Membership on an entity's Board of Directors or advisory committees; Syros: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees.

Abstract Abstract 3009FN2 Objective: To determine toxicity and efficacy of adding fludarabine (FLU) to a regimen of total body irradiation (TBI), anti-thymocyte globulin (ATG) and cyclophosphamide (CY), with de-escalation of the CY dose. The goal is to minimize CY-related toxicities while preserving (or improving) engraftment and survival in patients with SAA receiving an unrelated donor marrow transplant. Patients and Methods: Since May 2006, the Blood and Marrow Transplant Clinical Trials Network (BMT CTN), sponsored by the NHLBI and NCI, has conducted a prospective Phase I/II clinical trial of unrelated donor marrow transplantation in SAA (BMT CTN 0301). Patients with SAA are eligible if they are < 65 years, have adequate organ function, and have an available unrelated marrow donor matched 7 of 8 HLA-A, B, C, DRB1 loci. Patients with Fanconi anemia and other marrow failure syndromes are excluded. All patients receive TBI 200 cGy, ATG (either thymoglobulin: 3 mg/kg IV or ATGAM 30 mg/kg IV daily × 3, days –4 to –2), FLU (30 mg/m2 IV daily × 4, days –5 to –2). The Phase I portion of the trial sequentially tested four CY dose levels: 150 mg/kg (administered days –4 to –2); 100 mg/kg (days –3 to –2); 50 mg/kg (day –2); and, 0 mg/kg, and allowed enrollment of up to six patients at each CY dose level unless toxicity or graft failure boundaries were crossed. In the Phase II portion of the trial, patients enroll onto the optimal CY dose level, which is chosen using adaptive Bayesian criteria to rank desirability of the CY doses. All patients are followed for two years after transplantation. Early stopping guidelines are used to monitor for graft failure and early transplant-related mortality through day 100. Results: Twenty-one patients accrued to the Phase I portion of the trial. CY dose level 0 mg/kg was closed after all three enrolled patients developed secondary graft failure. All received a second allograft. One patient remains alive at 23 months after the first transplantation. The other two died from adult respiratory distress syndrome (ARDS) at 114 days after the first transplant and idiopathic pneumonia at 200 days after the first transplant. Review of Phase I results for the other three dose levels suggested CY dose 150 mg/kg as the optimal dose level for Phase II testing. However, after an additional eight patients were treated at this dose, the level was closed to further accrual because of excess toxicity. Seven of the 14 patients receiving 150 mg/kg of CY (and 7 of the last 8 enrolled) died. Causes of death were cardiac/pulmonary/multi-organ failure (n=4), ARDS (n=2), and parainfluenza virus type 3 pneumonia (n=1). Bayesian evaluation of the two remaining dose levels indicates very similar desirability scores and accrual continues at both the CY 100 mg/kg and 50 mg/kg levels. As of July 15, 2011, a total of 61 patients have been enrolled, 17 on the two closed levels, 33 on the 100 mg/kg level and 11 on the 50 mg/kg level. Conclusions: Early analysis of this trial, made necessary by these unexpected severe adverse events, revealed two important findings among patients receiving low-dose TBI, ATG, and FLU at the doses outlined: 1) CY dose 0 mg/kg is associated with higher than expected graft failure; and, 2) CY dose 150 mg/kg is associated with excess transplant-related toxicity. Neither CY dose level should be tested further in the context of the regimen used in this trial. To date, the two intermediate CY dose levels (100 mg/kg and 50 mg/kg) have not crossed the graft failure or fatality stopping boundaries and accrual is in progress. Disclosures: Pulsipher: Genzyme: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Abstract Systemic mastocytosis (SM) is a rare hematologic neoplasm characterized by abnormal growth and accumulation of tissue mast cells (MC) in various organ systems, including bone marrow (BM). Indolent and advanced forms of SM have been described. Whereas patients with ISM have a normal or near normal life-expectancy, patients with advanced SM, including those suffering from mast cell leukemia (MCL) have a poor prognosis. In these patients, neoplastic MC are usually resistant against conventional drugs and various targeted drugs. In rapidly progressive aggressive SM (ASM) and MCL, polychemotherapy followed by allogeneic hematopoietic stem cell transplantation (alloHCT) has been proposed. However, outcome of alloHCT in advanced SM is unknown, and it also remains uncertain whether clinically relevant graft-versus-SM (GVSM) effects may occur in these patients, as only sporadic case reports have been published. We performed a retrospective multi-center analysis to evaluate the outcome of alloHCT in patients with advanced SM. Fifty-four advanced SM patients receiving SCT in 32 transplantation centers in Europe and America were identified between 1990 and 2013. The median patient age was 45 years. Donors were: HLA identical siblings (31), unrelated donors (URD) (15), umbilical cord blood donors (UCB) (2), and haploidentical donors (1). In 5 patients, stem cell source was not defined (5). Thirty-four patients received myeloablative conditioning (MAC) and 18 received reduced intensity conditioning regimens (RIC). In 2 patients, conditioning regimen was not specified. Indications for alloHCT were SM with an associated clonal hematologic non-mast cell lineage disease (SM-AHNMD) (n=32), MCL (n=13, including one with MCL-AHNMD), 8 with ASM and 1 with myelomastocytic leukemia (MML). The most prevalent AHNMD was acute myeloid leukemia (AML, n=16). With follow-up of 35-6180 (median 365) days, SM responses (defined as ≥50% decrease in BM mast cells ± decrease in serum tryptase ± regression of other organ manifestations) were observed in 39 patients (72%), including complete responses (CR) documented in 12 patients (22%). Eleven patients had stable disease, whereas 4 patients (7%) progressed immediately after alloHCT (primary resistance). In addition, 10 patients progressed (5 of them within 100 days) after an initial response. Progression was most frequently seen in MCL patients (n=6, 50%). In the AHNMD group, only 8 patients relapsed/progressed (25%). The overall survival (OS) and SM progression-free survival (PFS) at 1 year were 63% and 50% for all patients, 77% and 68% for SM-AHNMD, 63% and 50% for ASM, and 25% and 17% for MCL, respectively. The strongest predictive variable associated with inferior survival was a diagnosis of MCL. Other factors associated with poor outcome were: Karnofsky performance status ≤70%, ≥2 SM regimens given before alloHCT (e.g., steroids, cladribine, chemotherapy, tyrosine kinase inhibitor), donor source (alternative donors-UCB and haploidentical compared to sibling or URD), SM progression within the first 100 days, normal cytogenetics (compared to t(8;21) (q22;q22), and RIC (compared to MAC). The following variables were not associated with poor outcome: patient and donor age, recipient-donor sex match status, graft source (BM vs. peripheral stem cells), BM mast cell percentage at time of alloHCT, and CR status of AML or SM response at time of alloHCT. This largest multi-center analysis of results in advanced SM provides evidence for clinical efficacy of alloHCT, presumably because of a GVSM effect of alloHCT (achieving CR, and response to donor-lymphocyte infusions and RIC alloHCT). However, responses varied among different SM categories: while patients with SM-AHNMD enjoyed excellent outcomes, the OS for MCL patients in general, was poor. Nevertheless it is remarkable that 3 of 13 patients with MCL – an otherwise fatal disease with a median survival of &lt;12 months – became long-term survivors after alloHCT. In summary, our results support development of a prospective alloHCT study, with the aim to optimize therapy and to improve overall outcome in advanced SM. Based on our pilot study, alloHCT should also be considered in practice for eligible and fit patients with SM-AHNMD (if treatment of AHNMD component needs alloHCT or SM component is aggressive), rapidly progressing ASM, MCL and MML when a suitable HLA-matched sibling donor or URD is available. Disclosures: Vercellotti: Sangart Inc.: Research Funding; Seattle Genetics: Research Funding. Akin:Novartis: Consultancy. Valent:Novartis: Consultancy, Honoraria, Research Funding.

Abstract BACKGROUND: Both thalidomide (Br J Haematol2002;117:288) and lenalidomide (Blood2006;108:1158) are effective for alleviating anemia in approximately 20% of patients with myelofibrosis (MF). However, the value of these drugs is undermined by their respective potential for peripheral neuropathy and severe myelosuppression. In the current study, we evaluated the safety and efficacy of the new immunomodulatory drug, pomalidomide (POM) in MF. METHODS: This is a phase-2 randomized, multicenter, double-blind, active-control, parallel-group study to determine safety and select a “Best” dose of POM alone or combined with prednisone (PRED). Patients were equally randomized to 4 treatment groups: POM (2 mg/day) + placebo, PRED (30 mg/day) + placebo, POM (2 mg/day) + PRED (30 mg/day), and POM (0.5 mg/day) + PRED (30 mg/day). POM therapy was given for up to twelve 28-day treatment cycles. PRED therapy was given in a tapering dose schedule during the first three of these 12 treatment cycles. Protocol eligibility criteria included absolute neutrophil count of ≥ 1 × 109/L, platelet count of ≥ 50 × 109/L and hemoglobin level of < 10 g/dL including red blood cell (RBC) transfusion requirement. Patients with prior thalidomide or lenalidomide therapy and/or venous thrombosis were excluded from study participation. Response was assessed by the International Working Group for Myelofibrosis Research and Treatment (IWG-MRT) criteria (Blood.2006;108:1497) and by independent analysis of the component variables. RESULTS: A total of 104 patients with MF were assessed for eligibility; 85 were randomized and 84 received the assigned therapy. Blinded data for the first 82 patients are presented here; median age was 67 years and MF subtype was PMF in 70% of the patients and post-PV/ET MF in 30%. All patients belonged to either intermediate or high risk disease category (Blood1996;88:1013); 42 (51%) were RBC transfusion-dependent. Median duration of disease before randomization was 3 years (range 2–14). The number of patients assigned to each arm was relatively balanced: 21, 20, 19 and 22, respectively. After a median treatment duration of 3 months, 42 (51%) patients have discontinued protocol therapy because of lack of therapeutic effect (n=19), withdrawal of consent (n=11), adverse event (n=11) or death (n=2). Grade 3/4 adverse events (regardless of attribution) included anemia (10%), thrombocytopenia (9%), leukopenia (9%), fatigue (7%), dyspnea (5%), thrombosis (4%), diarrhea (4%) and hyperglycemia (4%). Combined response rate using IWG-MRT criteria was 25% (95% CI, 16–34%) and ranged between 11% and 42% among the four treatment arms. CONCLUSION: Pomalidomide, with or without concomitant prednisone therapy, is well tolerated in patients with MF, especially from the standpoint of myelosuppression. Response rates are high. Additional, unblinded, information regarding response details, remission duration and laboratory correlative studies will be presented at the meeting.

Abstract Background: MDSs are clonal hematopoietic stem cell malignancies characterized by cytopenias resulting from ineffective hematopoiesis. A phase 2 study of lenalidomide (MDS-002) demonstrated hematological improvement in patients with MDS without an associated deletion 5q cytogenetic abnormality (List AF, et al. Haematologica2006;91[suppl1]:379[abst 1032]). We now report multicenter results after 〉2 yrs follow-up. Methods: A total of 214 pts with transfusion-dependent anemia were categorized into the following IPSS MDS risk groups after central review of bone marrow morphology, karyotype, and peripheral blood findings: Low/Int-1 (168 [78%]); Int-2/High (8 [4%]); and unclassified (38 [18%]). Patients were unclassified for missing or inadequate marrow studies for central review (morphology [29] or cytogenetic [7]) or other diagnoses (AML [1], atypical CML [1]). Patients were evaluated for frequency and duration of red blood cell transfusion independence (RBC-TI) (IWG criteria), hemoglobin (Hgb) response, and safety. The starting dose of lenalidomide was 10 mg (daily or daily × 3 wks q28d cycle). Results: Overall, 56 (26%) of 214 enrolled patients achieved RBC-TI. Median time to RBC-TI was 5 wks, median duration of RBC-TI response was 41.0 wks (range, 8.0–136.4), and median Hgb increase achieved during RBC-TI was 3.2 g/dL (range, 1.0–9.8). An additional 36 patients experienced a ≥ 50% reduction in RBC transfusions (overall hematological improvement in 92 [43%] patients). Overall, 47 (22%) patients had an abnormal karyotype at baseline and 9 (19%) patients achieved a cytogenetic response (4 complete). The most common drug-related grade 3/4 adverse events (AEs) were neutropenia and thrombocytopenia (25% and 20%, respectively). Deep vein thrombosis occurred in only 2 (1%) patients. The duration of RBC-TI was ≥ 52 weeks in 21 (38%) patients. Among these 21 patients, 14 (67%) did not require a lenalidomide dose reduction during the first 52 weeks of treatment. Analyses of response variables will be presented. Dose-limiting neutropenia/thrombocytopenia was not reported after 52 weeks. The most commonly reported AEs after 52 weeks were mild-moderate diarrhea and fatigue (38% and 29%, respectively). Conclusion: Lenalidomide is an active, well-tolerated treatment in MDS patients with transfusion-dependent anemia that is not associated with a deletion 5q abnormality. The rate of erythroid hematologic improvement and duration of RBC-TI is encouraging and offers a possible alternative to cytokine therapy.

PurposeAdvanced systemic mastocytosis (SM), a fatal hematopoietic malignancy characterized by drug resistance, has no standard therapy. The effectiveness of allogeneic hematopoietic stem-cell transplantation (alloHCT) in SM remains unknown.Patients and MethodsIn a global effort to define the value of HCT in SM, 57 patients with the following subtypes of SM were evaluated: SM associated with clonal hematologic non–mast cell disorders (SM-AHNMD; n = 38), mast cell leukemia (MCL; n = 12), and aggressive SM (ASM; n = 7). Median age of patients was 46 years (range, 11 to 67 years). Donors were HLA-identical (n = 34), unrelated (n = 17), umbilical cord blood (n = 2), HLA-haploidentical (n = 1), or unknown (n = 3). Thirty-six patients received myeloablative conditioning (MAC), and 21 patients received reduced-intensity conditioning (RIC).ResultsResponses in SM were observed in 40 patients (70%), with complete remission in 16 patients (28%). Twelve patients (21%) had stable disease, and five patients (9%) had primary refractory disease. Overall survival (OS) at 3 years was 57% for all patients, 74% for patients with SM-AHNMD, 43% for those with ASM, and 17% for those with MCL. The strongest risk factor for poor OS was MCL. Survival was also lower in patients receiving RIC compared with MAC and in patients having progression compared with patients having stable disease or response.ConclusionAlloHCT was associated with long-term survival in patients with advanced SM. Although alloHCT may be considered as a viable and potentially curative therapeutic option for advanced SM in the meantime, given that this is a retrospective analysis with no control group, the definitive role of alloHCT will need to be determined by a prospective trial.

Purpose Thalidomide and lenalidomide can alleviate anemia in myelofibrosis. However, their value is undermined by their respective potential to cause peripheral neuropathy and myelosuppression. We therefore evaluated the safety and therapeutic activity of another immunomodulatory drug, pomalidomide. Methods In a phase II randomized, multicenter, double-blind, adaptive design study, four treatment arms were evaluated: pomalidomide (2 mg/d) plus placebo, pomalidomide (2 mg/d) plus prednisone, pomalidomide (0.5 mg/d) plus prednisone, and prednisone plus placebo. Pomalidomide was administered for up to 12 28-day treatment cycles. Prednisone (30 mg/d) was given in a tapering dose schedule during the first three cycles. Response was assessed by International Working Group criteria. Results Eighty-four patients with myelofibrosis-associated anemia were randomly assigned to the aforementioned treatment arms: 22, 19, 22, and 21, respectively. Response in anemia was documented in 20 patients, including 15 who became transfusion independent. Response rates in the four treatment arms were 23% (95% CI, 5% to 41%), 16% (95% CI, 0% to 33%), 36% (95% CI, 16% to 56%), and 19% (95% CI, 2% to 36%). The corresponding figures for patients receiving ≥ 3 cycles of treatment (n = 62) were 38%, 23%, 40%, and 25%. Response to pomalidomide with or without prednisone was durable (range, 3.2 to 16.9+ months) and significantly better in the absence of leukocytosis (37% v 8%; P = .01); JAK2V617F or cytogenetic status did not affect response. Grade ≥ 3 toxicities were infrequent and included (in each treatment arm) neutropenia (9%; 16%; 5%; 5%), thrombocytopenia (14%; 16%; 9%; 5%), and thrombosis (9%; 5%; 0%; 0%). Conclusion Pomalidomide therapy at 0.5 or 2 mg/d with or without an abbreviated course of prednisone is well tolerated in patients with myelofibrosis and active in the treatment of anemia.

Lenalidomide is approved for red blood cell (RBC) transfusion-dependent anemia due to low or intermediate-1 (int-1) risk myelodysplastic syndromes (MDSs) associated with a chromosome 5q deletion with or without additional cytogenetic abnormalities. We report results of a multicenter, phase 2 trial evaluating lenalidomide therapy for transfusion-dependent patients with low- or int-1–risk MDS without deletion 5q. Eligible patients had 50 000/mm3 or more platelets and required 2 U or more RBCs within the previous 8 weeks; 214 patients received 10 mg oral lenalidomide daily or 10 mg on days 1 to 21 of a 28-day cycle. The most common grade 3/4 adverse events were neutropenia (30%) and thrombocytopenia (25%). Using an intention-to-treat analysis, 56 (26%) patients achieved transfusion independence (TI) after a median of 4.8 weeks of treatment with a median duration of TI of 41.0 weeks. In patients who achieved TI, the median rise in hemoglobin was 32 g/L (3.2 g/dL; range, 10-98 g/L [1.0-9.8 g/dL]) from baseline. A 50% or greater reduction in transfusion requirement occurred in 37 additional patients, yielding a 43% overall rate of hematologic improvement (TI response +‖≥ 50% reduction in transfusion requirement). Lenalidomide has clinically meaningful activity in transfusion-dependent patients with low- or int-1–risk MDS who lack the deletion 5q karyotypic abnormality. This study is registered at www.clinicaltrials.gov as no. NCT00064974.