Search

Chronic obstructive pulmonary disease (COPD) is associated with age and smoking, but other determinants of the disease are incompletely understood. Clonal hematopoiesis of indeterminate potential (CHIP) is a common, age-related state in which somatic mutations in clonal blood populations induce aberrant inflammatory responses. Patients with CHIP have an elevated risk for cardiovascular disease, but the association of CHIP with COPD remains unclear. We analyzed whole-genome sequencing and whole-exome sequencing data to detect CHIP in 48 835 patients, of whom 8444 had moderate to very severe COPD, from four separate cohorts with COPD phenotyping and smoking history. We measured emphysema in murine models in which Tet2 was deleted in hematopoietic cells. In the COPDGene cohort, individuals with CHIP had risks of moderate-to-severe, severe, or very severe COPD that were 1.6 (adjusted 95% confidence interval [CI], 1.1-2.2) and 2.2 (adjusted 95% CI, 1.5-3.2) times greater than those for noncarriers. These findings were consistently observed in three additional cohorts and meta-analyses of all patients. CHIP was also associated with decreased FEV1% predicted in the COPDGene cohort (mean between-group differences, −5.7%; adjusted 95% CI, −8.8% to −2.6%), a finding replicated in additional cohorts. Smoke exposure was associated with a small but significant increased risk of having CHIP (odds ratio, 1.03 per 10 pack-years; 95% CI, 1.01-1.05 per 10 pack-years) in the meta-analysis of all patients. Inactivation of Tet2 in mouse hematopoietic cells exacerbated the development of emphysema and inflammation in models of cigarette smoke exposure. Somatic mutations in blood cells are associated with the development and severity of COPD, independent of age and cumulative smoke exposure.

Background Hypercoagulability is a well-known mechanism of injury in patients with COVID-19 (Rico-Mesa et al Cardiology 2020). There are several clinical reports suggesting higher incidence of venous as well as arterial thromboembolism in the infected individuals. Patients with evidence of thromboembolism are at higher risk of poor outcomes as well (Bilaloglu et al JAMA 2020). The underlying mechanism is thought to be due to increased platelet aggregation and activation (Manne et al Blood 2020) along with inflammatory activation of the coagulation cascade that can lead to a hypercoagulable state (McGonagle et al Lancet Rheumatology 2020). There is a suggestion that anticoagulation is associated with reduction in mortality in COVID-19 infections (Paranjpe et al Cardiology 2020). However, the role of antiplatelet therapy has not been very well described or studied. In this study we investigated the outcomes for patients who were on antiplatelet therapy or full dose anticoagulation at baseline who developed COVID-19 infections. Methods This is a retrospective electronic chart review of patients admitted to New York-Presbyterian Brooklyn Methodist Hospital (NYP BMH), a Weill Cornell Medicine-affiliated hospital in Brooklyn, NY. Patients who were diagnosed and hospitalized for COVID-19 between March to April 2020 were included. Clinical data was extracted manually from electronic medical record (EMR). Patients were divided into 3 cohorts, considered "high risk" due to chronic comorbidities which required therapeutic anticoagulation and/or antiplatelet therapy. The first cohort included patients on single or dual antiplatelet therapy (Aspirin, Clopidogrel, Ticagrelor, Prasugrel, Aspirin-Dipyridamole or dual antiplatelet therapy) prior to admission and continued on admission (AP only). The second cohort included patients on anticoagulation (therapeutic Coumadin, Apixaban, Rivaroxaban, Enoxaparin) without antiplatelet therapy prior to admission, and continued on equivalent anticoagulation inpatient (AC only). The third included patients who were on both antiplatelet therapy and therapeutic anticoagulation (AP + AC). Additionally, we collected data on baseline characteristics, demographics, and outcomes. The primary outcome of the study was inpatient mortality. Secondary outcomes were median length of stay, ICU admission, Intubation requirement, bleeding, transfusions of blood products, development of venous thromboembolism and myocardial infarction. Chi-squared analyses were performed to determine statistical significance. Results We analysed 684 hospitalized patients who were diagnosed with COVID-19. Ages ranged from 18 to 101 years old, 52% were male, and 48% were black, with a median age of 70. There were 146 patients in the AP group, 34 patients in the AC group, 24 patients in the AP + AC group, and 480 patients were on neither. Our data was significant for mortality of 82% in the AC group, 36% in the AP group, and 38% in the AP + AC group (p value Conclusion We determined our patients to be those at high risk of thrombosis at baseline due to their requirement of antiplatelets or anticoagulation prior to hospitalization for COVID-19 infection. Our study suggests that mortality is higher for these patients who already required anticoagulation prior to COVID infection. Significantly, we demonstrated that patients on both therapeutic anticoagulation and antiplatelet therapy had less mortality than patients on anticoagulation alone, suggesting that antiplatelets in addition to anticoagulation might be protective against mortality in COVID-19 infection. Additionally, patients on antiplatelets and anticoagulation had less development of respiratory failure requiring intubation than either alone. This study provides proof of concept for prospective clinical trials for assessing the role of combination of antiplatelet therapy and therapeutic anticoagulation in high risk patients. Disclosures No relevant conflicts of interest to declare.

TO THE EDITOR: Vitamin B12 (VB12), or cobalamin, is a water-soluble vitamin. It serves as an enzyme cofactor in the 1-carbon metabolism pathway, which plays a key role in a wide range of biological processes, including red blood cell (RBC) formation, DNA synthesis, and myelination of the central

Background: The symptom burden for patients (pts) with acute myeloid leukemia (AML) is substantial, and patient reported outcomes (PROs) in pts with newly diagnosed (ND) AML ineligible for intensive induction chemotherapy (IIC) are poor. Baseline health status and conditions (ie, fatigue and physical functioning) are independent prognostic factors for overall survival and pts may benefit from improved quality of life (QoL) while undergoing treatment. To fully evaluate the impact of AML and its treatments, assessing health-related QoL and PROs has become increasingly important. Gilteritinib (GIL), an FMS-like tyrosine kinase 3 gene (FLT3) inhibitor, demonstrated efficacy/safety in pts with FLT3mut+ relapsed/refractory AML. In the phase 3 LACEWING (NCT02752035) trial, GIL was evaluated in combination with azacitidine (AZA) in pts with ND AML with FLT3 mutations who were unable to receive IIC. Aim/Objective: To evaluate prespecified PROs in pts with ND FLT3mut+ AML ineligible for IIC receiving GIL+AZA or AZA in LACEWING. Methods: PROs were obtained from pts in a safety cohort receiving GIL plus AZA and pts randomized (2:1) to GIL (120 mg/day orally on Days 1-28) plus AZA (75 mg/m 2/day SC/IV on Days 1-7) or AZA alone (same regimen) during 28-day cycles. All pts receiving GIL plus AZA (safety cohort and randomized) were included in the 'GIL+AZA' group. Patient reported fatigue, assessed by the Brief Fatigue Inventory (BFI), was a secondary endpoint; other PROs, assessed by the Functional Assessment of Chronic Illness Therapy-Dyspnea Short Form (FACIT-Dys-SF), Functional Assessment of Cancer Therapy-Leukemia (FACT-Leu), dizziness and mouth sore symptoms, and EuroQol Group 5-Dimension 5-Level (EQ-5D-5L), were exploratory endpoints. The BFI was administered at Cycle 1 (Days 1, 8, and 15), Cycle 2 (Days 1 and 15), and subsequent cycles on Day 1; all other assessments were administered on Day 1 of each cycle. All assessments were evaluated using analysis of variance models. Results: A total of 15 pts in the safety cohort and 123 randomized pts (GIL+AZA, n=74; AZA, n=49) were included. Median age was 78 years with GIL+AZA and 76 years with AZA; ECOG PS ≥2 was 50.6% and 32.7%, respectively, and FLT3-ITD was the only FLT3 mutation present in 76.4% and 81.6% of pts, respectively. Questionnaire completion rates for the BFI were 73% and 85% for patients in the safety and randomized cohorts, respectively. Baseline scores on assessment scales were similar between groups. A difference in favor of GIL+AZA was seen at Cycle 1, Day 8 on the BFI (least squares mean [LSM] difference [95% CI] -1.0 [-1.9, -0.2]; P=.019); differences were not significant at other time points. On the FACIT-Dys-SF dyspnea subscale score, pts receiving AZA reported improvement in dyspnea compared with pts receiving GIL+AZA (LSM difference [95% CI] 7.7 [0.5, 14.8]; P=.037) at Cycle 3, Day 1. No significant differences were seen at other time points on the FACIT-Dys-SF dyspnea subscale score or at any time for the functional limitation subscale score. On the FACT-Leu at Cycle 2, Day 1, LSM differences in favor of GIL+AZA were observed for physical and emotional well-being but were in favor of AZA on social well-being; at most time points, well-being did not differ between groups. At Cycle 2, Day 1, LSM differences favored GIL+AZA (8.1 [95% CI 0.5, 15.7]; P=.038) on the FACT-Leu Trial Outcome Index. No differences were observed between groups on other measures of the FACT-Leu. At baseline, very little dizziness (mean scores: GIL+AZA, 0.49 vs AZA, 0.63) and mouth sores (mean scores: GIL+AZA, 0.47 vs AZA, 0.48) were reported; no significant differences were observed at any time point while on treatment. A small but significant difference was seen in favor of GIL+AZA at Cycle 2, Day 1 on the EQ-5D-5L utility index (LSM difference [95% CI] 0.1 [0.0, 0.2]; P=.049), but not at other time points. No differences were observed between groups on the EQ-5D-5L visual analog scale scores measuring self-rated health status. Conclusions: Results from analyses of PRO data indicate that the addition of GIL to AZA for the treatment of patients with ND FLT3mut+ AML ineligible for IIC does not result in clinically significant change or worsening of fatigue, leukemia-related symptoms (including dizziness and mouth sores), and QoL compared with AZA treatment alone. From the patient's perspective, combination therapy with GIL+AZA is a feasible and well tolerated treatment strategy. Disclosures Wang: Kura Oncology: Consultancy, Honoraria, Other: Advisory board, steering committee, Speakers Bureau; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Rafael Pharmaceuticals: Other: Data safety monitoring committee; Kite Pharmaceuticals: Consultancy, Honoraria, Other: Advisory Board; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Consultancy, Honoraria, Other: Advisory Board; Stemline Therapeutics: Consultancy, Honoraria, Other: Advisory board, Speakers Bureau; Takeda: Consultancy, Honoraria, Other: Advisory board; DAVA Oncology: Consultancy, Speakers Bureau; BMS/Celgene: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Consultancy, Honoraria, Other: Advisory Board; Novartis: Consultancy, Honoraria, Other: Advisory Board; Mana Therapeutics: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria, Other: Advisory Board, Speakers Bureau; Gilead: Consultancy, Honoraria, Other: Advisory board; Daiichi Sankyo: Consultancy, Honoraria, Other: Advisory board; PTC Therapeutics: Consultancy, Honoraria, Other: Advisory board; Genentech: Consultancy; MacroGenics: Consultancy. Heuser: Tolremo: Membership on an entity's Board of Directors or advisory committees; BergenBio: Research Funding; BMS/Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer Pharma AG: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: Research Funding; Astellas: Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Honoraria; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding. Montesinos: Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Stemline/Menarini: Consultancy; Glycomimetics: Consultancy; Tolero Pharmaceutical: Consultancy; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Teva: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Forma Therapeutics: Consultancy; Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Agios: Consultancy; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Astellas Pharma, Inc.: Consultancy, Honoraria, Other: Advisory board, Research Funding, Speakers Bureau. Rich: Astellas Pharma Global Development, Inc.: Current Employment. Wu: Astellas: Current Employment. Pandya: Astellas Pharma, Inc.: Current Employment. Shah: Astellas Pharma, Inc.: Current Employment; University of Michigan School of Public Health Department of Health Management and Policy Alumni Board: Other: Chair-Elect.

Background: Gilteritinib (GIL), a FLT3 inhibitor, shows efficacy/safety in patients (pts) with FLT3mut+ relapsed/refractory (R/R) AML. For pts with newly diagnosed (ND) AML with FLT3 mutations unable to receive intensive induction chemotherapy (IIC), survival is limited, and therapy options are few. In preclinical studies, GIL plus azacitidine (AZA) impeded tumor growth and induced apoptosis/differentiation of FLT3-ITD AML cell lines. Antitumor effects appeared synergistic in xenografted mouse models (data on file). We investigated GIL+AZA vs AZA in adults with ND FLT3mut+ AML ineligible for IIC (NCT02752035). Aim/Objective: To compare efficacy and safety/tolerability of GIL+AZA and AZA in pts with ND FLT3mut+ AML ineligible for IIC. Methods: Pts were initially randomized (1:1:1) to GIL (120 mg/day orally on Days 1-28) plus AZA (75 mg/m 2/day SC/IV on Days 1-7), AZA (same regimen), or GIL (same regimen) during 28-day cycles. The GIL arm was removed due to preferred therapy changes. Pts were then randomized (2:1) to GIL+AZA or AZA alone. The primary endpoint was overall survival (OS) and key secondary endpoint was event-free survival (EFS). Treatment failure date was randomization date if complete remission (CR) was not achieved after 6 cycles. Subgroup/sensitivity analyses were prespecified. Response rates, safety/tolerability, and pharmacokinetic endpoints were analyzed. Data from long-term follow-up ≤3 yrs were obtained, including subsequent AML therapy. These results are from an interim analysis at 70 deaths (~50% of total deaths). Results: As of August 26, 2020, 123 pts were randomized to GIL+AZA (n=74) and AZA (n=49); 39 (52.7%) and 31 (63.3%) deaths, respectively, occurred. Median age was 78 yrs with GIL+AZA and 76 yrs with AZA; ECOG PS ≥2 was 47.3% and 32.7%, and FLT3-ITD alone was in 78.4% and 81.6% of pts, respectively (TKD alone 18.9% vs 14.3%; ITD with TKD 2.7% vs 4.1%). Median follow-up was 9.76 mo for GIL+AZA and 17.97 mo for AZA. Median exposure duration was 112 days for GIL in the GIL+AZA arm (n=73); AZA exposure was 98 and 99 days in the GIL+AZA and AZA (n=47) arms, respectively. Subsequent AML therapy was received by 20.3% pts on GIL+AZA and 44.9% pts on AZA; median time to first subsequent therapy was 8.2 and 4.5 mo, respectively. In the AZA arm, 22 pts received subsequent AML therapy, including 10 pts on GIL and 4 pts on other FLT3 inhibitors. Median OS was 9.82 mo for GIL+AZA and 8.87 mo for AZA (HR 0.916 [95% CI 0.529, 1.585]; P=.753). Patient subgroups with improved OS with GIL+AZA vs AZA included pts with ECOG PS 0-1 (HR 0.811 [95% CI 0.409, 1.608]) and high FLT3-ITD allelic ratio ≥0.5 (HR 0.580 [95% CI 0.285, 1.182]). Median EFS was 0.03 mo in both arms (HR 1.175 [95% CI 0.764, 1.807]; P=.459). In sensitivity analyses, median EFS with events based on composite CR (CRc; CR+CRi+CRp) was 5.03 mo for GIL+AZA and 3.29 mo for AZA (HR 0.924 [95% CI 0.576, 1.482]; P=.767). Although CR rates for both arms were similar (16.2% vs 14.3%), CRc rates were significantly higher for GIL+AZA vs AZA (58.1 vs 26.5%, difference 31.4% [95% CI 13.1, 49.7]; P No substantial differences in GIL trough concentrations at steady state (C trough) were seen between GIL+AZA and GIL alone (prior to arm removal). However, on Cycle 1 Day 15, median GIL C trough was 579 ng/mL (GIL+AZA and GIL arms) in contrast to C trough of 279 ng/mL observed with GIL monotherapy in the ADMIRAL trial in pts with R/R AML. Reasons for this difference are being evaluated. No apparent relationship was seen between C trough and response rates/grade of thrombocytopenia or neutropenia. Conclusions: In this trial of pts with ND FLT3mut+ AML ineligible for IIC, GIL+AZA led to significantly higher CRc rates but similar OS vs AZA alone. Pts with ECOG PS 0-1 and high FLT3-ITD allelic ratio appeared to have greater benefit with GIL+AZA. No new safety signals were seen. Curiously, C trough values in pts with ND FLT3mut+ AML ineligible for IIC were 2-fold greater than in pts with R/R FLT3mut+ AML. These results support the safety, tolerability, and activity of GIL+AZA vs AZA. Disclosures Wang: GlaxoSmithKline: Consultancy, Honoraria, Other: Advisory Board; Genentech: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Other: Advisory Board; Jazz Pharmaceuticals: Consultancy, Honoraria, Other: Advisory Board; Pfizer: Consultancy, Honoraria, Other: Advisory Board, Speakers Bureau; Takeda: Consultancy, Honoraria, Other: Advisory board; Mana Therapeutics: Consultancy, Honoraria; Kite Pharmaceuticals: Consultancy, Honoraria, Other: Advisory Board; Kura Oncology: Consultancy, Honoraria, Other: Advisory board, steering committee, Speakers Bureau; Stemline Therapeutics: Consultancy, Honoraria, Other: Advisory board, Speakers Bureau; BMS/Celgene: Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; DAVA Oncology: Consultancy, Speakers Bureau; Rafael Pharmaceuticals: Other: Data safety monitoring committee; Gilead: Consultancy, Honoraria, Other: Advisory board; Daiichi Sankyo: Consultancy, Honoraria, Other: Advisory board; PTC Therapeutics: Consultancy, Honoraria, Other: Advisory board; Genentech: Consultancy; MacroGenics: Consultancy. Montesinos: Stemline/Menarini: Consultancy; Sanofi: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Forma Therapeutics: Consultancy; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Glycomimetics: Consultancy; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Tolero Pharmaceutical: Consultancy; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding; Teva: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Agios: Consultancy; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Astellas Pharma, Inc.: Consultancy, Honoraria, Other: Advisory board, Research Funding, Speakers Bureau. Minden: Astellas: Consultancy. Lee: Korean Society of Hematology: Membership on an entity's Board of Directors or advisory committees; Astellas Pharma, Inc.: Consultancy, Honoraria, Other: Advisory board; AbbVie: Honoraria, Other: Advisory board. Heuser: Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees, Research Funding; BergenBio: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: Research Funding; Tolremo: Membership on an entity's Board of Directors or advisory committees; BMS/Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer Pharma AG: Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Honoraria; Jazz: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astellas: Research Funding. Naoe: Fuji Film: Other: Study funding for JAGSE; Astellas Pharma, Inc.: Consultancy, Other: Study funding for JAGSE; Bristol-Myers: Honoraria; Nippon Shinyaku: Honoraria; Daichi Sankyo: Other: Study funding for JAGSE; Otsuka Pharma: Honoraria. Chou: Abbvie: Honoraria, Other: Advisory Board, Research Funding; Celgene: Honoraria, Other: Advisory Board, Research Funding; IQVIA: Honoraria, Other: Advisory Board; Pfizer: Honoraria, Other: Advisory Board; Novartis: Honoraria, Other: Advisory Board; Bristol Myers Squibb: Honoraria, Research Funding; Kirin: Honoraria, Research Funding. Laribi: IQONE: Other: Personal Fees; Takeda: Other: Personal Fees, Research Funding; AstraZeneca: Other: Personal Fees; BeiGene: Other: Personal Fees; Astellas Phama, Inc.: Other: Personal Fees; Jansen: Research Funding; AbbVie: Other: Personal Fees, Research Funding; Le Mans Hospital: Research Funding; Novartis: Other: Personal Fees, Research Funding. Esteve: Jazz: Consultancy; Novartis: Research Funding; Bristol Myers Squibb/Celgene: Consultancy; Pfizer: Consultancy; Abbvie: Consultancy; Novartis: Consultancy, Research Funding; Astellas: Consultancy. Altman: ALZ Oncology: Research Funding; Amgen: Research Funding; Biosight: Consultancy, Other: Travel fees, Research Funding; Kartos: Research Funding; Boehringer Ingelheim: Research Funding; Daiichi Sankyo: Consultancy; Syros: Consultancy; BMS: Research Funding; GlycoMimetics: Other: Participation on an advisory board; Aprea: Research Funding; Kura: Research Funding; Kura Oncology: Consultancy; AbbVie: Consultancy, Other: Advisory Board, Research Funding; Theradex: Consultancy, Other: Advisory boards; Fujifilm: Research Funding; Astellas: Consultancy, Other: Advisory Board, Research Funding; Immunogen: Research Funding. Havelange: Astellas Pharma, Inc.: Consultancy; Novartis: Honoraria, Other: Travel fees, Participation on an advisory board; BMS: Other: Travel fees, Participation on an advisory board; Incyte: Other: Advisory board; Abbvie: Other: Advisory board. Watson: Astellas Pharma, Inc.: Consultancy; Roche, Amgen: Other: Travel support. Patkowska: Astellas Pharma, Inc.: Consultancy, Other: Travel fees; Pfizer: Other: Travel fees; Jazz Pharmaceuticals: Other: Travel fees; Angelini Pharma: Honoraria, Other: Travel fees; Novartis: Honoraria, Other: Travel fees; Bristol-Myers Squibb: Other: Travel fees; AMGEN: Honoraria; Servier: Honoraria, Other: Travel fees; KCR US, Inc.: Consultancy. Liu: Astellas Pharma, Inc.: Current Employment. Wu: Astellas: Current Employment. Philipose: Astellas Pharma Global Development: Current Employment. Hill: Astellas Pharma Global Development: Current Employment; Ligacept, LLC: Current holder of individual stocks in a privately-held company, Other: Stockholder. Gill: Astellas Pharma Global Development: Current Employment. Rich: Astellas Pharma Global Development, Inc.: Current Employment. Tiu: Astellas Pharma, Inc.: Current Employment.

Background: The presence of measurable residual disease (MRD) after achievement of remission with induction therapy is a prognostic marker of relapse risk in patients with acute myeloid leukemia (AML). Gilteritinib is an oral FLT3 inhibitor approved as a single agent for the treatment of patients with FLT3-mutated (FLT3mut+) relapsed or refractory AML. Evaluation of gilteritinib in the front-line setting is under way. We evaluated FLT3 internal tandem duplication (FLT3-ITD) mutation clearance using two different thresholds and correlated mutation clearance with survival outcomes in patients with newly diagnosed AML ineligible for intensive chemotherapy who were treated with front-line gilteritinib plus azacitidine (AZA) or either agent alone in the phase 2/3 LACEWING trial. Methods: Adult patients with newly diagnosed FLT3mut+ AML ineligible for intensive induction chemotherapy received 28-day cycles of once-daily gilteritinib plus AZA in the Safety Cohort (80 or 120 mg/day gilteritinib plus 75 mg/m 2 AZA, Days 1-7) and in Arm AC (120 mg/day gilteritinib plus 75 mg/m 2 AZA, Days 1-7), gilteritinib (120 mg/day) alone in Arm A, or AZA (75 mg/m 2, Days 1-7) alone in Arm C. A subset of patients who had a best overall response of composite complete remission (CRc; defined as the sum of patients who achieved complete remission with or without complete hematologic or platelet recovery) and who had bone marrow-derived DNA samples available at baseline and at least one additional post-baseline timepoint were assessed for FLT3-ITD mutation clearance using next-generation sequencing. An Illumina ® sequencing platform was used to quantify FLT3-ITD and total FLT3 alleles. The FLT3-ITD variant allelic frequency (VAF) was defined as the ratio of FLT3-ITD to total FLT3 frequency. Data were analyzed using two different mutation clearance thresholds, FLT3-ITD VAF Results: The median age of patients enrolled in LACEWING was 77 years (range, 59-90), with 73% of patients aged >75 years. Although baseline characteristics of the overall LACEWING population were generally well balanced across treatment arms, higher proportions of patients treated with gilteritinib plus AZA (47%) or gilteritinib alone (59%) had an Eastern Cooperative Oncology Group (ECOG) performance status of ≥2 compared with patients treated with AZA alone (33%). Overall, 40 patients who achieved CRc and had sufficient DNA samples from bone marrow aspirates obtained at baseline and at least one additional post-baseline timepoint were included in the analysis (Safety Cohort, n=8; Arm A, n=7; Arm AC, n=17; and Arm C, n=8). Across both thresholds, the proportions of patients with FLT3 mutation clearance did not markedly differ between patients treated with gilteritinib or AZA (Table). In patients who received gilteritinib, FLT3-ITD mutation clearance using either threshold was associated with a similar increase in median overall survival (OS) compared to patients who did not achieve mutation clearance (Figure). Conclusions: Regardless of MRD threshold, rates of MRD negativity were not substantially different between newly diagnosed FLT3mut+ AML patients ineligible for intensive induction chemotherapy who received gilteritinib alone, gilteritinib plus AZA, or AZA alone. Advanced age coupled with a worse baseline ECOG performance score at baseline may have compromised treatment response and achievement of FLT3 mutation clearance in patients treated with gilteritinib. The mutation clearance thresholds used in this analysis showed similar median OS in patients who received gilteritinib. Figure 1 Figure 1. Disclosures Wang: Pfizer: Consultancy, Honoraria, Other: Advisory Board, Speakers Bureau; Genentech: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Consultancy, Honoraria, Other: Advisory Board; Novartis: Consultancy, Honoraria, Other: Advisory Board; Kura Oncology: Consultancy, Honoraria, Other: Advisory board, steering committee, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Honoraria, Other: Advisory Board; Takeda: Consultancy, Honoraria, Other: Advisory board; Kite Pharmaceuticals: Consultancy, Honoraria, Other: Advisory Board; Stemline Therapeutics: Consultancy, Honoraria, Other: Advisory board, Speakers Bureau; Mana Therapeutics: Consultancy, Honoraria; BMS/Celgene: Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; DAVA Oncology: Consultancy, Speakers Bureau; Rafael Pharmaceuticals: Other: Data safety monitoring committee; Gilead: Consultancy, Honoraria, Other: Advisory board; Daiichi Sankyo: Consultancy, Honoraria, Other: Advisory board; PTC Therapeutics: Consultancy, Honoraria, Other: Advisory board; Genentech: Consultancy; MacroGenics: Consultancy. Altman: Kartos: Research Funding; Theradex: Consultancy, Other: Advisory boards; Biosight: Consultancy, Other: Travel fees, Research Funding; Daiichi Sankyo: Consultancy; AbbVie: Consultancy, Other: Advisory Board, Research Funding; BMS: Research Funding; Amgen: Research Funding; Astellas: Consultancy, Other: Advisory Board, Research Funding; Fujifilm: Research Funding; ALZ Oncology: Research Funding; Immunogen: Research Funding; GlycoMimetics: Other: Participation on an advisory board; Syros: Consultancy; Kura Oncology: Consultancy; Boehringer Ingelheim: Research Funding; Aprea: Research Funding; Kura: Research Funding. Minden: Astellas: Consultancy. Wu: Astellas: Current Employment. Rich: Astellas Pharma Global Development, Inc.: Current Employment. Hill: Ligacept, LLC: Current holder of individual stocks in a privately-held company, Other: Stockholder; Astellas Pharma Global Development: Current Employment.

Introduction COVID-19 is an ongoing pandemic that has impacted millions of individuals throughout the world. The spectrum of clinical features of COVID-19 can vary from asymptomatic infection to severe multiorgan failure leading to death. There is no single biomarker available that can predict the trajectory of the infected patient. Few clinical reports suggest a correlation between the severity of COVID-19 and elevation of certain hematological and inflammatory markers. We used a novel COVID-19 Prognostic Score (CPS) which included lymphocyte count, elevated lactate dehydrogenase (LDH), C-reactive protein (CRP) and ferritin levels to predict the outcomes of COVID-19 patients. Methods We performed a retrospective chart review of COVID-19 patients admitted to New York Presbyterian Brooklyn Methodist Hospital between March and April of 2020. Clinical data was extracted manually from electronic medical records. Patients were divided into 2 cohorts. The first cohort included a combination of low lymphocyte count, elevated LDH, CRP and ferritin. The second cohort included normal lymphocyte count, low LDH, CRP and ferritin. Low lymphocyte count was defined as < 20% of white blood cell count (WBC), high LDH as ≥ 300 U/L, high CRP as ≥50mg/L and high ferritin as ≥600 ng/mL. Statistical analysis was performed by computing odds ratio using a p-value of < 0.05 as statistically significant. Results We analyzed 683 hospitalized patients who were diagnosed with COVID-19 confirmed via viral PCR resting. The median age was 66.5 years, males were 52.2% and blacks were 47.2%. 16.3% had coronary artery disease (CAD), 38.6% had Diabetes Mellitus (DM), 63.1% had hypertension and 21.6% had pulmonary disease. 181 patients (26.5%) were intubated and transferred to ICU. The median LDH was 438 U/L, the median CRP was 107 mg/L and the median ferritin was 687 ng/mL. 4.6% of patients developed a thromboembolic event. The overall inpatient mortality rate was 32.1%. There were 178 patients in the CPS-High cohort while there were 41 patients who qualified for the CPS-Low cohort. The median age of CPS-High was 65 years and the median age of CPS-Low was 58 years. The percentage of CAD, DM, hypertension, pulmonary disease in CPS-High and CPS-Low were 11.8%, 39.3%, 57.9%, 10.7% and 19.5%, 17.1%, 43.9%, 12.2% respectively. In the CPS-High cohort the overall inpatient mortality was 42% while the inpatient mortality rate for CPS-Low was 7.3%. In univariate analysis, patients who had CPS low had significantly reduced inpatient mortality (Odds ratio 0.108, 95% CI 0.03-0.36, p-value = 0.0003). Discussion Our study suggests that a combination of hematological characteristics and inflammatory markers can be used to assess the severity of illness with COVID-19. This study shows that there is a likelihood of 6-times higher mortality with COVID-19 if all the clinical characteristics are abnormal including lymphocyte count, LDH, CRP, and ferritin. This simple clinical prognostic score can be used at the time of hospital admission to efficiently triage patients, which may likely improve the outcomes of these patients. This prognostic tool needs to be validated in a larger dataset or prospective clinical study. Disclosures No relevant conflicts of interest to declare.

Introduction The outcomes related to different anticoagulation doses in Coronavirus disease 2019 (COVID-19) patients are not well established. COVID-19 is associated with increased thrombotic events and early coagulopathy as reported by a large New York City health system. Initial studies on patients in Wuhan, China showed anticoagulant therapy mainly with low molecular weight heparin was reported to be associated with better prognosis in severe COVID-19 patients meeting sepsis-induced coagulopathy criteria or with markedly elevated D-dimer. These studies fueled the need for anticoagulation protocols to be institutionalized broadly. Here we report the outcomes of patients on prophylactic compared to treatment dose anticoagulation early in the COVID-19 pandemic. This data reflects results before broad institutionalization of anticoagulation protocols for this novel disease in a Brooklyn, New York population. Methods This is a retrospective chart review of all laboratory confirmed COVID-19 patients who were admitted to New York-Presbyterian Brooklyn Methodist Hospital between March and April, 2020. Patient clinical characteristics were manually extracted from electronic medical records. Patients were divided into 2 groups: patients on treatment dose anticoagulation and patients on prophylactic dose anticoagulation. Primary outcome of this study was inpatient mortality among the two groups. Secondary outcomes were thromboembolisms (both arterial and venous), myocardial infarction (MI), major bleeding, ICU admission, ICU length of stay, invasive mechanical ventilation and initiation of dialysis. Odds ratio and p-values were obtained using univariate analysis. Results We analyzed 580 hospitalized patients with confirmed nasopharyngeal COVID19 infection. Of these, 82 patients were on treatment dose anticoagulation 498 patients were on prophylactic dose. Median age was 70 years in treatment dose group and 66 years in prophylactic dose group. Percentage of males were similar between both groups (53%). African American race(56% vs 46%) was the predominant race in both groups. Median BMI was 28.1 in both groups. Percentage of smokers was higher in the treatment dose group (34% compared to 21%). Patients in the treatment dose group had a higher rate of all the comorbidities. Median D-Dimer (630 vs 590) was higher in the treatment dose group. Rates of ICU admission in treatment dose group and prophylactic dose group was 44% and 22% respectively. Patients requiring intubation (43% vs 24%) and transfusion (24% and 7%) were higher in the treatment dose group. There was an increased incidence of thromboembolic events in the treatment dose group as compared to prophylactic dose group with DVT (15.6% vs 1.6%) PE (3.7% vs 0.2%), arterial thrombosis (1.2% vs 0%) and MI (6.1% vs 1.6%). Incidence of major bleeding was higher in the treatment group (10% vs3.5%) Discussion Our study found increased inpatient mortality with treatment dose anticoagulation and increased risk of bleeding when compared with prophylactic dose anticoagulation. These findings may be due to higher rates of comorbidities, smoking and older age when compared to the prophylactic anticoagulation group. Higher rates of bleeding raises concern for the safety of treatment dose anticoagulation in these populations. Some limitations of this study include: uneven sample size between the two groups and data was collected from patients before anticoagulation dose recommendations were standardized and officially implemented. Further randomized control trials are needed to evaluate the dose- dependent relationship between anticoagulation and mortality. Our study suggests that the treatment dose anticoagulation may adversely affect the outcomes in COVID-19 patients who are older and have multiple comorbidities. Therefore, the anticoagulation dose must be chosen carefully given the overall clinical picture. Disclosures No relevant conflicts of interest to declare.

Introduction: There is conflicting data on the association of blood type with COVID-19 infection. Recent studies have shown an association of blood type in acquisition of COVID-19 infection (Zhao et al., medRxiv 2020), but no association in terms of disease mortality (Latz, Ann Hematol 2020). Prior studies are limited due to lack of diversity. One of the largest studies conducted in China found blood type A conferred highest risk of acquiring COVID-19 infection (Zhao et al., medRxiv 2020). Similar results were found in which the odds of COVID-19 positive infection compared to negative test results were increased in blood group A and decreased in blood group O (Zietz et al., medRxiv 2020). There was no significant association between blood group and intubation or death. Neither of these studies addressed the association of blood groups with thromboembolism. This study aimed to evaluate the impact of blood types on outcomes of COVID-19 infection in a multiracial population. Methods: This is a retrospective electronic chart review of all patients admitted to New York-Presbyterian Brooklyn Methodist Hospital in Brooklyn, NY. All patients admitted from March 2020 to April 2020 who tested positive for SARS-CoV-2 nasopharyngeal swab were analyzed. Baseline patient characteristics and outcomes were entered manually by medical professionals via chart review using the electronic medical record (EMR). Baseline characteristics include blood group type, rhesus antigen status, age, gender, race, comorbid conditions, median initial and peak D-dimer. The primary endpoint was inpatient mortality. The secondary endpoints included thromboembolism (pulmonary embolism, deep venous thrombosis, arterial thrombosis), myocardial infarction, bleeding event, length of stay, intensive care unit admission, and intubation. Chi-square test for categorical variables was used to calculate statistical significance defined as p value ≤ .05 when comparing ABO blood group and rhesus antigen with mortality and development of thromboembolism. Results: Our study consisted of 249 patients that were COVID-19 positive with a documented blood group. Our population consisted of 51% of patients that identified as black, 35.7% that identified as white, and 17.7% that identified as Hispanic. Blood type B had the highest rate of patients that identified as black at 58.1% and blood type O had the highest rate that identified as Hispanic at 23.6%. When comparing blood groups A, AB, B and O to the rate of mortality the result was 46%, 44.4%, 41.9% and 50.9% respectively which was found to be not statistically significant (p=0.759). Rh positive patients had a 47.2% mortality rate while Rh negative patients had a 46.9% mortality rate however this was also found to be not statistically significant (p=0.954). Next, we compared development of thromboembolism during hospital stay in the A, AB, B, and O blood type groups and the rate was 8%, 11.1%, 9.3%, and 10.9% respectively with the results not being statistically significant when accounted for blood type (p=0.991). Rate of development of thromboembolism in Rh positive and negative patients was 9.3% and 9.4% respectively which was found to not be statistically significant as well (p=0.998). When looking at comorbidities, 70.2% of our patient population had hypertension and the second prevalent comorbidity was diabetes at 38.2% (Table 1). Discussion: In a diverse population, no association between ABO blood group, Rh status, and mortality was found which is similar to the conclusion found in prior studies done by Zhao et al. and Latz et al. in which the majority of the population was either Caucasian or Asian. Additionally, there is no association found between ABO blood group, Rh status and development of thromboembolism. Our patient population consisted mostly of minority groups. Prior studies have shown that blood type A has the highest risk of positive SARS-CoV-2 test whereas type O has the lowest risk of positive SARS-CoV-2 test. Our study further supplements this discovery by the conclusion that while blood type A conferred highest risk of acquiring COVID-19 infection, blood type had no significant association with mortality. Investigation on a larger scale is necessary to address the susceptibility of ABO blood group and COVID-19 infection severity in a multiracial population to address racial disparities. Disclosures No relevant conflicts of interest to declare.

Nodular lymphocyte Hodgkin lymphoma (NLPHL) is a rare disease for which the optimal therapy is unknown. We hypothesized that rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) could decrease rates of relapse and transformation. We retrospectively reviewed patients with NLPHL diagnosed between 1995 and 2015 confirmed by central pathologic review. Fifty-nine had sufficient treatment and follow-up data for analysis. We described progression-free survival (PFS), overall survival (OS), and histologic transformation according to treatment strategy and explored prognostic factors for PFS and OS. The median age at diagnosis was 41 years; 75% were male, and 61% had a typical growth pattern. Twenty-seven patients were treated with R-CHOP with an overall response rate of 100% (complete responses 89%). The median follow-up was 6.7 years, and the estimated 5- and 10-year PFS rates for patients treated with R-CHOP were 88.5% (95% confidence interval [CI], 68.4% to 96.1%) and 59.3 (95% CI, 25.3% to 89.1%), respectively. Excluding patients with histologic transformation at diagnosis, the 5-year cumulative incidence of histologic transformation was 2% (95% CI, 87% to 100%). No patient treated with R-CHOP experienced transformation. A high-risk score from the German Hodgkin Study Group was adversely prognostic for OS (P = .036), whereas male sex and splenic involvement were adversely prognostic for PFS (P = .006 and .002, respectively) but not OS. Our data support a potential role for R-CHOP in patients with NLPHL. Larger prospective trials are needed to define the optimal chemotherapy regimen.

Despite a central role for B-cell receptor precursor (pre-BCR) pathway in precursor B-cell acute lymphoblastic leukemia (B-ALL), there is limited available data on therapies that aim to disrupt this pathway. Mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) is a para-caspase required for BCR-mediated NF-κB activation. We recently showed that targeting MALT1 with the small molecule inhibitor MI2 is effective in CLL, including drug-resistant clones (Saba Can Res 2017). We sought to examine the role of MALT1 in B-ALL and determine the biological consequences of inhibiting its activity. First, we tested MALT1 expression by immunoblot in B-ALL using 17 cell lines representing the disease spectrum (7 pro-B: REH, SEMK2, TOM1, RS4;11, NALM21, Z119, BV173; 8 pre-B: HB11;19, NALM6, RCH-ACV, SMS-SB, 697, KASUMI2, KOPN8, HPB-NULL; and 2 mature/Burkitt: 2F7, RAJI), and found that MALT1 was expressed in all cell lines at different levels. To determine sensitivity to MALT1 inhibition we used two molecules: Z-VRPR-fmk, a highly selective MALT1 blocking peptide, and MI2, a small molecule MALT1 inhibitor. Z-VRPR-fmk resulted in a dramatic cell growth inhibition in most of our B-ALL cell lines, with appropriate positive (TMD8) and negative (K562) controls, independent of the cell-of-origin (pro, pre, mature) or the presence of the Philadelphia chromosome. We did not observe a clear correlation between MALT1 level and degree of sensitivity to Z-VRPR-fmk. Interestingly, the two ibrutinib-resistant cell lines RS4;11 and 697, were amongst the top sensitive cell lines to MALT1 inhibition. A similar pattern of cell sensitivity was observed when these cell lines were treated with MI2, resulting in an IC50 at 48h of 0.2 µM in RS4;11 and < 0.5 µM in other sensitive cell lines, which is consistent with published data in sensitive DLBCL cell lines (IC50, 0.2-0.5 µM), and our data on the CLL cell line MEC1 (IC50, 0.2 µM). We then tested freshly collected PBMCs from patients with various blood cancers presenting with a leukemic phase against serial dilutions of MI2 for 48h (7 B-ALL, 24 CLL, and 4 CML). In addition, we included normal B-cells collected from five volunteers. Interestingly, B-ALL samples showed the highest sensitivity to MI2, followed by CLL, while the rest were resistant. The proteolytic activity of MALT1 can be studied by measuring its ability to cleave its targets such as A20, CYLD, BCL10, Roquin, Regnase and RelB. Surprisingly, with the exception of the Burkitt cell line 2F7, we did not detect cleavage of these targets at baseline, nor after proteasomal inhibition with MG-132 or following crosslinking of pre-BCR with anti-IgM in pre-B ALL, the latter successfully increased AKT phosphorylation. The constitutive activation of MALT1 in 2F7 was effectively inhibited by Z-VRPR-fmk as determined by a marked reduction in targets cleavage concomitant with an increase in full length proteins. We are expanding the mature B-ALL cell line cohort to include TANOUE, BALL-1, DAUDI, GA-10, and NC-37 cell lines to further explore to role of MALT1 in this disease subset. Collectively, these data highly suggest distinct roles for MALT1 in B-ALL: pro and pre-B-ALL vs. mature B-ALL. To explore the possibility of distinct role for MALT1 in B-ALL, arguably independent of BTK and of signaling through BCR, we used RNA sequencing to determine the changes in gene expression profiling following a 24h treatment with Z-VRPR-fmk in 3 highly sensitive B-ALL cell lines (RS4;11, HPB-NULL, and 697). Out of 39,514 tested genes, there were 160 genes whose expression changed ≥ 2-fold at P < 0.05 (84 down- and 76 up-regulated). Gene Set Enrichment Analysis (GSEA) identified 34 Hallmark and Oncogenic Signatures gene sets relevant to B-ALL that were all downregulated by Z-VRPR-fmk (FDR < 10%, and normalized enrichment score (NES) ≥ 1.50). Among those gene sets, mTOR-S6K and TANK-binding kinase 1 (TBK1)-dependent gene signatures stood out as the most affected. MALT1 was shown to be involved in the ribosomal protein S6 phosphorylation through activation of mTOR/AKT signaling. Indeed, treatment with MI2 and Z-VRPR resulted in a significant decrease in S6 phosphorylation in RS4;11 and SEMK2. In conclusion, MALT1 plays a critical role in B-ALL survival likely through a novel mechanism that involves mTOR-S6K pathway, independently from pre-BCR/BCR signaling. Supported by a grant from the Ladies Leukemia League, Inc., of the Gulf South Region. Disclosures Saba: Kyowa Kirin: Consultancy; AbbVie: Consultancy; Janssen: Consultancy, Speakers Bureau; Pharmacyclics: Consultancy, Speakers Bureau. Melnick:Epizyme: Consultancy; Janssen: Research Funding; Constellation: Consultancy. Wiestner:Merck: Research Funding; Nurix: Research Funding; Pharmayclics: Research Funding; Acerta: Research Funding. Burger:AstraZeneca: Honoraria; Aptose Biosciences, Inc: Research Funding; Gilead Sciences: Research Funding; Janssen Pharmaceuticals: Consultancy, Honoraria; Pharmacyclics, an AbbVie company: Research Funding; BeiGene: Research Funding. Safah:Celgene: Speakers Bureau; Incyte: Speakers Bureau; Verastem: Honoraria, Speakers Bureau; Jazz: Speakers Bureau; Amgen: Honoraria, Speakers Bureau.

Several rare European von Willebrand disease missense variants of VWF (including p.Arg2185Gln and p.His817Gln) were recently reported to be common in apparently healthy African Americans (AAs). Using data from the NHLBI Exome Sequencing Project, we assessed the association of these and other VWF coding variants with von Willebrand factor (VWF) and factor VIII (FVIII) levels in 4468 AAs. Of 30 nonsynonymous VWF variants, 6 were significantly and independently associated (P < .001) with levels of VWF and/or FVIII. Each additional copy of the common VWF variants encoding p.Thr789Ala or p.Asp1472His was associated with 6 to 8 IU/dL higher VWF levels. The VWF variant encoding p.Arg2185Gln was associated with 7 to 13 IU/dL lower VWF and FVIII levels. The type 2N-related VWF variant encoding p.His817Gln was associated with 17 IU/dL lower FVIII level but normal VWF level. A novel, rare missense VWF variant that predicts disruption of an O-glycosylation site (p.Ser1486Leu) and a rare variant encoding p.Arg2287Trp were each associated with 30 to 40 IU/dL lower VWF level (P < .001). In summary, several common and rare VWF missense variants contribute to phenotypic differences in VWF and FVIII among AAs.

Prolonged immunodeficiency after allogeneic bone marrow transplantation (BMT) causes significant morbidity and mortality from infection. This study examined in murine models the effects of interleukin-7 (IL-7) given to young and middle-aged (9-month-old) recipients of major histocompatibility complex (MHC)–matched or –mismatched allogeneic BMT. Although administration of IL-7 from day 0 to 14 after syngeneic BMT promoted lymphoid reconstitution, this regimen was ineffective after allogeneic BMT. However, IL-7 administration from day 14 (or 21) to 27 after allogeneic BMT accelerated restoration of the major lymphoid cell populations even in middle-aged recipients. This regimen significantly expanded donor-derived thymocytes and peripheral T cells, B-lineage cells in bone marrow and spleen, splenic natural killer (NK) cells, NK T cells, and monocytes and macrophages. Interestingly, although recipients treated with IL-7 had significant increases in CD4+ and CD8+ memory T-cell populations, increases in naive T cells were less profound. Most notable, however, were the observations that IL-7 treatment did not exacerbate graft-versus-host disease (GVHD) in recipients of an MHC-matched BMT, and would ameliorate GVHD in recipients of a MHC-mismatched BMT. Nonetheless, graft-versus-leukemia (GVL) activity (measured against 32Dp210 leukemia) remained intact. Although activated and memory CD4+ and CD8+ T cells normally express high levels of IL-7 receptor (IL-7R, CD127), activated and memory alloreactive donor-derived T cells from recipients of allogeneic BMT expressed little IL-7R. This might explain the failure of IL-7 administration to exacerbate GVHD. In conclusion, posttransplant IL-7 administration to recipients of an allogeneic BMT enhances lymphoid reconstitution without aggravating GVHD while preserving GVL.

The Na+/H+ exchanger isoform 1 (NHE1) is primarily responsible for the regulation of intracellular pH (pHi). It is a ubiquitous, amiloride-sensitive, growth factor–activatable exchanger whose role has been implicated in cell-cycle regulation, apoptosis, and neoplasia. Here we demonstrate that leukemic cell lines and peripheral blood from primary patient leukemic samples exhibit a constitutively and statistically higher pHi than normal hematopoietic tissue. We then show that a direct correlation exists between pHi and cell-cycle status of normal hematopoietic and leukemic cells. Advantage was taken of this relationship by treating leukemic cells with the Na+/H+ exchanger inhibitor, 5-(N, N-hexamethylene)-amiloride (HMA), which decreases the pHiand induces apoptosis. By incubating patient leukemic cells in vitro with pharmacologic doses of HMA for up to 5 hours, we show, using flow cytometry and fluorescent ratio imaging microscopy, that when the pHi decreases, apoptosis—measured by annexin-V and TUNEL methodologies—rapidly increases so that more than 90% of the leukemic cells are killed. The differential sensitivity exhibited between normal and leukemic cells allows consideration of NHE1 inhibitors as potential antileukemic agents.

Chronic granulomatous disease (CGD) is a rare inherited disorder of phagocytes in which defective production of microbicidal oxidants leads to severe recurrent infections. CGD is caused by mutations in any of 4 genes encoding components of nicotinamide adenine dinucleotide phosphate (reduced form; NADPH) oxidase, the multisubunit enzyme that produces the precursor of these oxidants, superoxide. Approximately 5% of CGD patients have an autosomal recessive form of disease caused by a severe deficiency of p67-phox, a 526-amino acid subunit of the oxidase that appears to regulate electron transport within the enzyme. Here we report the biochemical and molecular characterization of 6 unrelated kindreds with p67-phox deficiency. These studies show that, as in gp91-phox and p22-phox deficiencies, the p67-phox CGD patients show a high degree of heterogeneity in the genetic defects that underlie their disease. Five different mutant alleles were identified: (1) a nonsense mutation in exon 4 (C304 → T); (2) a 5-nucleotide (nt) deletion in exon 13 (nts 1169-1173); (3) a splice mutation in the first nucleotide of intron 4 (G → A); (4) a deletion of 1 nt in exon 9 (A728); and (5) a 9-nt in-frame deletion in exon 2 (nts 55-63). The splice mutation was seen in 3 unrelated kindreds, while the 5-nt deletion was seen in 2 apparently unrelated families (both of Palestinian origin). Homozygosity was present in 4 of the kindreds, 2 of which had consanguineous parentage. In the isolated neutrophils of each of the affected patients in the 6 kindreds, there was no measurable respiratory burst activity and no p67-phox protein detected by immunoblot analysis. The level of 67-phox mRNA was less than 10% of normal in the mononuclear leukocytes from 3 of the 4 patients analyzed by Northern blot studies. Thus, this heterogeneous group of mutations in p67-phox all lead to marked instability of mRNA or protein (or both) that results in the complete loss of NADPH oxidase activity.