ALBERT

Description: Background: In 1994 Severe Chronic Neutropenia International Registry (SCNIR) opened for enrollment of patients with at least 3 absolute neutrophil counts (ANC) less than 0.5 x 109/L during a three month period. At that time severe chronic neutropenia (SCN) was categorized as cyclic, congenital, autoimmune or idiopathic based largely on clinical criteria. A randomized trial had established effectiveness of treatment with granulocyte colony-stimulating factor (G-CSF), but long-term consequences of such treatment were unknown. Hypothesis: We began the SCNIR based on the hypothesis that underlying pathophysiology, natural history of patients with chronic neutropenia and benefits and risk of G-CSF therapy could only be accurately established through an international registry with long term follow-up of patients with these rare hematological disorders. Methods: SCNIR enrollment requires informed consent, ANC90%) of severe outcomes (e.g. MDS/AML, failure to respond to G-CSF, death from infections, need for stem cell transplant) often many years after SCNIR enrollment and beginning G-CSF therapy. GSD1 patients improve with G-CSF treatment, but experience splenomegaly and continued problems with infections or complications. The SCNIR through a SDS sub-registry is redefining Shwachman-Diamond syndrome; only about one-half of enrollees have “classic” presentation and a substantial number with “classic presentation” lack mutations in SBDS. The SCNIR is participating in an NIH trial of a CXCR4 antagonist for treatment of WHIM syndrome, as an example of molecularly targeted treatment for this rare disease. The SCNIR is also the key resource for discovery of genetic causes for congenital neutropenia, e.g., G6PC3, HAX1, and TCIRG1 and others, recognition of differences in frequency of autosomal dominant and recessive SCN in populations of Europe and North America and identifying congenital neutropenia cases of unknown cause. Genetic testing has also broadened the clinical spectrum of these disorders. Conclusions: Through the efforts of patients, families, physicians, nurses and investigators, and with support from the NIH, industry, and private philanthropy, chronic neutropenia is now far better understood at the genetic, molecular and cellular level than 20 years ago. Treatment responses to G-CSF are well characterized; novel therapies are emerging; and the prognosis for patients with SCN appears to be improving. The knowledge gained through the SCNIR and availability of G-CSF has redefined clinicians’ approach to chronic neutropenia. The SCNIR is a model of international research collaboration to understand rare diseases in hematology and other areas of medicine. Broad enrollment criteria, physician, patient and family participation, a dedicated staff, and continuing cooperation underlie success of the SCNIR and this model to understanding rare diseases. Disclosures Dale: Amgen: Consultancy, Honoraria, Research Funding. Boxer:Amgen: Equity Ownership. Morrow:Amgen: Employment.

Description: Background: Since 1994 the Severe Chronic Neutropenia International Registry (SCNIR) has enrolled children and adults with 〉 3 absolute neutrophil counts (ANCs) 〈 0.5 x 109/L during a 3 month period to understand the pathobiology, natural history and treatment responses for severe chronic neutropenia. We have previously reported on the frequency and risk of myelodysplasia (MDS) and acute myeloid leukemia (AML) in patients with congenital neutropenia. For this report we reviewed patterns of hematological complications and malignancies occurring in all patients enrolled through the North American office of the SCNIR. Methods: Enrollment required informed consent, and patients and their physicians provided demographic, clinical and laboratory data including bone marrow results. Genetic testing was not required. Patients were followed with annual reports on blood counts, infections, malignancies and hospitalizations. Results: From 1994 to 2018 the Seattle SCNIR office has enrolled 1672 patients in the following categories: congenital 637 (38%), cyclic 259 (15%), and idiopathic / autoimmune 776 (47%), and many have been followed now for more than 15 years. There are approximately 17,577 person years of the observational data in this Registry. The congenital category now includes patients with mutations in ELANE, SBDS, TAZ, COH1, CXCR4, SLC37A4, G6PC3, WAS, CSF3R, SRP54, GFI1, VPS45, JAGN1, HAX1 and also patients with severe neutropenia from an early date in childhood without a genetic diagnosis. Cyclic neutropenia patients have demonstrated oscillations in ANC. The idiopathic and autoimmune category includes children and adults including some with large granular lymphocytes (LGL) syndrome without recognized features of a lymphoproliferative disorder. Most patients in all categories have been treated with granulocyte colony-stimulating factor (G-CSF). Findings: MDS or AML has occurred in 70 of the 1672 patients; 99% have clinical diagnosis of a hereditary type of neutropenia: severe congenital neutropenia (55), glycogen storage disease 1b (3), congenital immunodeficiency (2), Shwachman-Diamond syndrome (SDS) (5), WHIM syndrome (1),Wiskott-Aldrich syndrome (2), cyclic neutropenia (1) and idiopathic neutropenia (1). The median age at diagnosis of AML/MDS was 15.3 years (mean 18.3, +/- 1.79 SEM [range 0.40 - 70.6]); 69 of 70 were treated with G-CSF, median dose = 7.1 mcg/kg/day (mean 7.3, +/- 1.3 SEM )(range 0.18 - 100). One Shwachman-Diamond patient never received G-CSF. Outcomes for AML/MDS patients receiving chemotherapy with HSCT before 2000 were poor with 3/17 (18%) survivors. Since 2000 there were 35/53 (66%) survivors. Five patients developed myelofibrosis (4 congenital and 1 idiopathic). Two of the congenital patients later developed AML (1 living after treatment with a HSCT, 1 deceased). The clinical diagnosis of cyclic neutropenia has a favorable prognosis with G-CSF treatment, with only one probable case in 3,833 person years of clinical observation. 1 Twelve patients developed T-cell lymphoproliferative disorder (1 autoimmune neutropenia, 3 congenital neutropenia, 8 idiopathic neutropenia (4 with LGL features)). Five of these patients are living, all in the idiopathic group, 3 of 5 living patients have features of the LGL syndrome. Ten patients have reported other hematological malignancies; CML in a congenital patient after treatment with HSCT (living), CLL in a cyclic patient (living), CMML in an idiopathic patient after treatment with a HSCT (deceased). Six of the 10 patients have developed lymphoma; cyclic neutropenia (1), idiopathic/autoimmune neutropenia (5). Only one SDS patient has developed aplastic anemia. Other cancers/non-hematological malignancies have occured mostly in older patients: breast cancer (15) colon cancer (6), dermatological malignancies (13), hepatoma (1), lung cancer (1), prostate cancer (1), thyroid cancer (1). Conclusions: The hematological consequences of severe chronic neutropenia depend on the underlying etiology. MDS and AML occur largely in patients with the congenital or hereditary neutropenias. The diagnosis of cyclic neutropenia and chronic idiopathic / autoimmune neutropenia portends a favorable prognosis, based on a total of 10482 person years of observation. Marrow failure and aplastic anemia are not expected consequences of severe chronic neutropenia. Disclosures Dale: Athelas, Inc.: Equity Ownership; Amgen: Consultancy, Research Funding; Sanofi-Aventi: Consultancy, Honoraria; Cellerant: Other: Scientific Advisory Board; Hospira: Consultancy; Prolong: Consultancy; Beheringer-Ingelheim: Consultancy; Coherus: Consultancy. Newburger:X4 Pharmaceutics: Consultancy, Honoraria; TransCytos LLC: Consultancy; Janssen Research & Development, LLC: Consultancy, Honoraria.

Description: Severe congenital neutropenia (SCN) is an inborn disorder of granulopoiesis characterized by severe chronic neutropenia from birth, premature death secondary to infectious complications, and transformation to myeloid malignancy. Although many cases of SCN are associated with mutations in ELANE, encoding the neutrophil elastase, roughly one-third of cases do not have an identifiable genetic cause. In collaboration with the Severe Chronic Neutropenia International Registry (SCNIR), we performed exome sequencing on 90 cases of congenital neutropenia. Heterozygous missense mutations of CLPB were identified in six patients with SCN. None of these patients had mutations in other genes known to cause SCN. A total of 5 different mutations were identified that clustered within the ATPase domain. Of note, all of these mutations were predicted to be functionally deleterious and had a frequency of

Description: Shwachman-Diamond syndrome (SDS) is an inherited marrow failure syndrome associated with exocrine pancreatic dysfunction and an increased risk of myelodysplasia and leukemia. The majority of individuals with SDS carry biallelic SBDS gene mutations, however a subset of patients remain genetically undefined. The objective of this study was to compare the clinical characteristics of patients with and without SBDS mutations. To address these questions, we conducted a retrospective study of patients enrolled on the North American Shwachman-Diamond Syndrome Registry (SDSR). Clinical data from the SDSR were available for 55 individuals with biallelic SBDS mutations and 16 individuals who fulfilled clinical diagnostic criteria for SDS but lacked biallelic mutations in the SBDS gene. Study subject ages for SBDS mutation positive and negative cohorts span 2-52.4 and 2.8-21.4 years with median ages of 12.4 and 10.9 years respectively. Cytopenias were present for both SBDS mutation positive and negative cohorts, with neutropenia the most common event in 94% and 81% respectively. Bone marrow hypocellularity was reported in 91% of those with SBDS mutations and 69% of those without. Marrow dysplasia was reported in 65% of those with SBDS mutations and none of those without. Clonal abnormalities were present in 44% and 25% of those with and without SBDS mutations with median age of initial appearance at 9 years (0.8-45.1) and 7 years (1.2-14) respectively. Abnormalities included del7q and del20q in both groups as well as iso7q, trisomy 8 and others in the SBDS mutation positive group. Clonal abnormalities were all transient in the SBDS mutation negative cohort. One SBDS mutation positive individual developed AML. None of the SBDS mutation negative individuals developed malignancy or progressed to require HSCT thus far. Pancreatic dysfunction determined by low serum trypsinogen or pancreatic isoamylase was similar in both cohorts 79% vs 80%. However, only 27% (15/55) of SBDS mutation positive individuals reported requiring enzyme therapy with 33% (18/55) documenting failure to thrive, in contrast to 75% (12/16) of SBDS mutation negative individuals with 73% (11/15) having failure to thrive. A broad spectrum of congenital anomalies were reported in 55% and 56% of SBDS mutation positive and negative individuals respectively, with skeletal anomalies being the most common in both groups. Medical comorbidities commonly reported in both groups included eczema and endocrinopathies. Elevated liver transaminases were seen in 27% of SBDS mutation positive individuals but this was not seen in the SBDS mutation negative cohort. Conclusion: Patients with genetically undefined (SBDS mutation negative) SDS share clinical characteristics with SBDS mutation positive patients; however, the risk of leukemia in the genetically undefined patients remains unclear due to low patient numbers with short follow-up. Further studies of this young cohort are required to inform medical management and to advance our understanding of genetic etiology, mechanism, disease pathophysiology and treatment of these marrow failure disorders. Disclosures Dale: Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau.

Description: Background: Mutations in ELANE are the most common cause of both cyclic and severe congenital neutropenia. Congenital neutropenia is characterized by low neutrophil counts in peripheral blood and impaired survival and maturation of myeloid precursors in bone marrow. G-CSF and HSCT are currently the only effective treatment options. To date, more than 100 different ELANE mutations have been reported. We previously described that some mutations (e.g. G214R and C151Y) are associated with more severe outcomes, while others (e.g. P139L and R220Q) result in relatively mild clinical phenotypes. (Curr Op Hematol. 2015;22:3-11) To explain the biological effects of various ELANE mutants we have created CRISPR/Cas9 edited ELANE mutants using the commercially available human promyelocytic cell line HL60. Methods: We used CRISPR/Cas9 editing technology to create engineered HL60 cell lines with ELANE P139L and C151Y single point heterozygous mutations. Both ELANE mutant cell lines as well as wild-type HL60 cells were cultured for 7 days in complete RPMI supplemented with 2uM all-trans retinoic acid (ATRA) to trigger myeloid differentiation. Survival of these cell lines was investigated using Annexin V-PE staining and flow cytometric analysis. Granulocytic differentiation was evaluated using CD11b surface marker staining and flow cytometry and by performing manual differential cell counts. Unfolded protein response (UPR) was measured by western blotting using UPR specific antibodies. MK-0339 is a potent, cell permeable, orally absorbed inhibitor of neutrophil elastase (NE), previously investigated in preclinical and clinical studies by Merck/DuPont as a potential anti-inflammatory drug. We have recently reported that MK-0339 increases cell survival and myeloid differentiation in cellular models of ELANE associated neutropenia. (Makaryan, et al, J Leukoc Biol. 2017;102(4):1143-1151). We examined the effects of MK-0339 on these cell lines. Results: Annexin V staining showed more than 2-fold increase in apoptotic cells in both mutant cell lines compared to wild-type. Granulocytic differentiation measured by surface CD11b expression was significantly impaired in both mutant cell lines (p-values

Description: White blood cell counts (WBC) and absolute neutrophil counts (ANC) are well-established predictors of a patient's risk of fever and infections or febrile neutropenia (FN). Currently, patients at risk of FN due to cancer chemotherapy, idiosyncratic drug-reactions or congenital neutrophil disorders are monitored at hospital or clinic laboratories. For many patients, effective and frequent monitoring is difficult due to the time required and costs of repeated laboratory visits. We herein present the first results for a novel device called Athelas One, a miniature point-of-care hematology analyzer suitable for at home monitoring of WBC and ANC. Methods: Athelas One (A1) is a small cylindrical device with a built-in, single head, light microscope. To determine the WBC and ANC, a small drop of blood (~ 3.5 uL) from a finger stick or an anticoagulated blood sample is drawn by capillary action onto a specially designed microfluidic test strip which creates a stained, precisely dimensioned monolayer of blood cells. The slide is then inserted into the device which scans the test strip and reports the WBC and ANC based on an image analysis process (Computer Vision). We compared results for A1 with a standard laboratory counter [Sysmex XE5000 (SX)]. Results: Initially, A1's reproducibility was demonstrated using 43 blood samples with a wide range of known WBCs (i.e., samples with normal counts, leukocytosis, leukopenia, neutropenia, neutrophilia) run on 4 devices using a single lot of test strips. The A1 results were then compared to SX results using the Passing Bablok Regression with Bootstrap method. These results showed strong linearity and comparability between paired anti-coagulated venous blood samples and the blood samples compared to finger prick capillary blood samples collected almost simultaneously. The slope and intercept indicated a linear relationship, with a 95% confidence for interval slope and intercept containing 1 and 0 respectively. (Comparisons: A1 blood to SX blood: WBC, r=0.998, ANC, r=0.989; A1 capillary to SX blood: WBC, r=0.998, ANC, r=0.97). Table 1 and Figure 1 show a summary of the comparisons. In addition to these results, we have tested 18 samples with WBC 〈 1.0 x 109/L with closely comparable results for A1 and standard hospital counter. Summary: These initial results show that the WBC and ANC can be accurately determined with a finger stick drop of blood and this point-of-care hematology analyzer. Given its small size, ease of use and accuracy, the device is suitable for home monitoring. Disclosures Dale: Athelas, Inc.: Equity Ownership; Amgen: Consultancy, Research Funding; Sanofi-Aventi: Consultancy, Honoraria; Cellerant: Other: Scientific Advisory Board; Hospira: Consultancy; Prolong: Consultancy; Beheringer-Ingelheim: Consultancy; Coherus: Consultancy. Navarro-De La Vega:Athelas, Inc.: Employment. Parthasarathy:Athelas, Inc.: Employment, Equity Ownership. Bodapati:Athelas, Inc.: Employment, Equity Ownership, Patents & Royalties: patent owned by Athelas on the Athelas One device. Virey:Athelas, Inc.: Employment, Equity Ownership, Patents & Royalties: patent owned by Athelas on the Athelas One device. Moffatt:Athelas, Inc.: Employment, Equity Ownership, Patents & Royalties: patent owned by Athelas on the Athelas One device. Tandon:Athelas, Inc.: Employment, Equity Ownership, Patents & Royalties: patent owned by Athelas on the Athelas One device.