Pongdee, Thanai

Objectives: To analyze variations in patient characteristics, treatment patterns, clinical manifestations, clinical outcomes (i.e., response, flares and flare-free survival in HES; remission, relapses and relapse-free survival in EGPA; and overall survival), and healthcare resource utilization (HCRU) in patients with hypereosinophilic syndrome (HES) and eosinophilic granulomatosis with polyangiitis (EGPA) across five European countries. Methods: In two parallel, retrospective, non-interventional, longitudinal chart review studies (GSK ID: 214661 [EGPA] and 214657 [HES]), physicians collected data of patients they treated in France, Germany, Italy, Spain, and the UK from January 2015 to December 2019, with follow-up until August 2021. Country-level results are presented for each study; HES and EGPA data were pooled in a post hoc exploratory analysis. Results: Per-country, 22–26 HES- and 38–45 EGPA-treating physicians collected data from 52–62 (total 280) patients with HES and 80–85 (total 407) with EGPA. Patient sex and age at diagnosis differed across countries. Pooled HES/EGPA data revealed high oral corticosteroid (OCS) use in all countries (94.9% of patients; median [IQR] duration 20.7 [9.0, 33.8] months); immunosuppressive treatments and biologics use varied between countries (43.7–61.5% and 25.6–59.8%, respectively). The most frequent clinical manifestations were constitutional (51.6–78.8%) and lung (43.5–55.8%) in HES, and lung (41.3–67.9) and ENT (43.8–61.2) in EGPA. Pooled HCRU data showed country-level variation; 70.7–91.2% of patients had disease-related outpatient visits and 36.1–52.6% had ER visits or hospitalizations. Conclusions: Results demonstrate substantial disease burden, including high HCRU and extensive OCS use among patients with HES and EGPA in five European countries. The findings highlight the need for improved treatment strategies such as optimizing use of biologics to mitigate the reliance on corticosteroids.

e18596 Background: The International Consensus (ICC), but not the 5 th edition of the WHO classification (WHO5), distinguishes mature from immature mast cell leukemia (MCL) and systemic mastocytosis (SM) associated with myeloid neoplasm (SM-AMN) from SM associated with myeloid or lymphoid neoplasm (SM-AHN). The objectives of the current study were i) to assess prognostic input from disease classification by ICC vs. WHO5, and ii) to compare the predictive performance of the Mayo Alliance Prognostic scoring (MAPS) with other prognostic models and its prognostic interaction with the ICC-based morphologic classification. Methods: Study patients met diagnostic criteria per ICC/WHO5. MAPS risk variables included i) age >60 years, ii) hemoglobin below sex-adjusted lower limit of normal, iii) platelets <150 × 10⁹/L, iv) alkaline phosphatase above upper limit of normal, and v) advanced, including MCL, SM-AMN, and aggressive (ASM) vs. indolent/smoldering (ISM/SSM) SM. ICC-defined MCL includes only MCL-immature whereas WHO-defined MCL includes both MCL-immature and MCL-mature. WHO-defined SM-AHN includes SM-AMN and SM associated with lymphoid neoplasm (SM-ALN). Results: 910 Mayo Clinic patients with SM were diagnosed between 1968 and 2024 (median age 56 years). ICC categories were ISM/SSM (N=552), ASM (N=115), SM-AMN (N=235), and MCL (N=8). At median follow-up of 4 years, 345 (38%) deaths and 35 (3.8%) leukemic transformations were documented. Overall survival (OS) predictive performance at 5 years was superior with ICC (AUC 0.85), compared to WHO5 (AUC 0.83); median survival was 24.3 years in ISM/SSM, 5.8 years for ASM, 2.0 years for SM-AMN, 2.3 years for SM-AHN, 1.8 years for MCL-mature and 0.08 years for MCL-immature; the difference in OS was significant between MCL-immature and SM-AMN (p<0.01) but not between MCL-mature and SM-AHN (p=0.3). Similarly, OS was similar between MCL-mature and ASM (p=0.8) and between SM-ALN and ASM (p=0.08) but different between MCL-immature and ASM (p<0.01), SM-AMN and ASM (p<0.01), and MCL-mature and MCL-immature (p<0.01). Predictive performance at 5 years was superior with MAPS (AUC 0.91) and MAPS-molecular (AUC 0.91), compared to the mutation-adjusted risk score (MARS; AUC 0.82). Median OS estimates were not reached, 24.2, 11.7, 5.7, 2.6, and 0.7 years, in the presence of 0, 1, 2, 3, 4, or 5 of the forementioned MAPS risk factors. Among informative cases, ASXL1 mutation was the only genetic risk factor with MAPS-independent prognostic relevance. Prognostic inter-independence between ICC and MAPS was confirmed by multivariable analysis. Conclusions: The current study confirms the superior performance of MAPS, in regard to survival prediction, with little additional contribution from mutations. SM sub-classification by the ICC is prognostically independent of MAPS and more valuable than classification by WHO5.

Abstract RATIONALE: Hypereosinophilic syndrome (HES) is a group of rare diseases characterized by persistent hypereosinophilia causing organ damage/dysfunction. Idiopathic and lymphocytic HES (I-HES/L-HES) subgroups exclude clonal and reactive HES. We evaluated real-world clinical outcomes of patients with I-HES/L-HES. METHODS: This retrospective observational cohort study of patients with I-HES/L-HES collected data from the TriNetX Linked Network of de-identified Electronic Health Records plus Claims in the US. Patients had a HES diagnosis (ICD-10-CM: D72.11) between 10/01/2020–09/12/2023, with ≥12 months continuous enrollment before their first HES diagnosis record (index date [ID]). Patients with myeloproliferative/reactive HES, or a diagnosis of eosinophilic granulomatosis with polyangiitis after HES diagnosis, were excluded. Baseline was defined as 12 months prior to ID. Year 1 was defined as 12 months after ID. Patients were followed up until either 09/12/2023, disenrollment from insurance, death, or 24 months after ID, whichever came first. Clinical response was defined as ≥3 months without HES symptoms and a blood eosinophil (bEOS) count ≤750 cells/µL. Complete hematological remission was defined as a bEOS count ≤500 cells/µL. Partial remission was defined as a bEOS count &lt;50% of baseline value, but &gt;500 cells/µL. Kaplan-Meier curves estimated time to first HES flare and hematological remission. Analyses were descriptive. RESULTS: At ID, patients with I-HES/L-HES (N=110) had a mean (standard deviation [SD]) age of 43.8 (21.3) years; 66 (60.0%) were male, 58 (52.7%) were White and 30 (27.3%) were Black or African American. Mean (SD) follow-up was 15.1 (7.7) months. Median (95% confidence interval [CI]) time from ID to first flare (n=47) was 18.0 (11.0, not estimated) months (Table 1). Median (95% CI) time to first complete or partial hematological remission (n=52) was 15.3 (10.8, 21.6) months. The proportion of patients with a definite or probable HES flare was lower at Year 1 (10/69 [14.5%]) versus baseline (40/110 [36.4%]). Few patients achieved clinical response at baseline (10/110 [9.1%]) and Year 1 (5/69 [7.2%]). Among patients with bEOS data, mean (SD) bEOS count was 2235.3 (4351.7) cells/µL at baseline (n=51) and 833.6 (1396.0) cells/µL at Year 1 (n=11). The proportion of patients with a bEOS count &lt;500 cells/µL was 20/51 (39.2%) at baseline and 7/11 (63.6%) at Year 1. CONCLUSION: Despite a reduced proportion of patients experiencing flares within a year after diagnosis, many did not experience hematological remission or clinical response by Year 1; suggesting high disease burden with existing treatment and the need for novel therapies to better manage I-HES/L-HES.

Objectives/Goals: Community-based practices have limited research opportunities for providers. As a rural community-based health system, Mayo Clinic Health System (MCHS) sought to create intramural funding mechanisms to help early-stage researchers conduct pilot research so they are more competitive to compete for more robust extramural funding opportunities. Methods/Study Population: We created a Research Seed Grant Program infrastructure across our four MCHS regions (Southwest and Southeast Minnesota, Northwest and Southwest Wisconsin). This model program featured an initial research funding announcement call based on 6 prioritized programs (AI Validation & Stewardship, Cancer, Health Equity, Population Health, Rural Health, Learning Healthcare System [LHS]), with submissions uploaded to a central electronic repository. Proposal review and ranking was organized on a regional basis, with ranking of all proposals by at least 2 clinical scientist reviewers according to the NIH domain-specific framework (i.e., 1.0 best > 9.0 worst). Awards were competitively selected by conformity to prioritized research areas and through ranking of most competitive overall application scores. Results/Anticipated Results: For our inaugural RFA, we received 55 grant application submissions across the MCHS regions. Fifteen of the most highly ranked applications were selected for awards on a per region basis, providing direct funding as well as protected investigator research time of 10% for up to six months. The selected projects address several research priorities including improving access, reducing health disparities, improving behavioral health in our communities, increasing cancer screening and prevention, and community-based pragmatic trials and interventions. Outcomes from these now completed pilot projects remain pending at this time. Funding for this seed grant program was supported by philanthropy, Mayo Clinic Research Administration, Mayo Clinic Comprehensive Cancer Center, and the Mayo Clinic CCaTS Rural Core. Discussion/Significance of Impact: We present this framework for a LHS-focused Seed Grant program model for consideration of adoption by other national/international LHS. Future plans include tracking of outcome metrics (e.g., published peer review articles, extramural grant applications) of this initial cycle and future expansion of this program to support the goals of our LHS.

In this review, we discuss the risks and adverse effects reported for the current Food and Drug Association (FDA)-approved biologics used in the management of asthma, including omalizumab, benralizumab, dupilumab, mepolizumab, reslizumab, and tezepelumab. Our review focuses on the risk of hypersensitivity reactions, infection, and malignancy. Where relevant, we have included information regarding the risk of cardiovascular disease and eosinophilia, and we have included specific information regarding vaccine use among patients receiving the above biologics. We also review currently available data regarding the use of biologics in the context of pregnancy. Our goal is to provide a comprehensive resource for providers utilizing these agents, so that they may adequately counsel patients about the risks of therapy and identify adverse events if they occur.

Introduction: Hypereosinophilic syndrome (HES) is a group of rare diseases characterized by persistent hypereosinophilia in the blood and/or tissues, causing organ damage and dysfunction. This retrospective observational cohort study described the real-world disease burden and clinical characteristics of patients with idiopathic HES (I-HES) or lymphocytic HES (L-HES). Methods: Records of patients with I-HES or L-HES were collected from the TriNetX Linked Electronic Health Records (EHR) plus Claims Network, a database of de-identified EHR-derived data linked to closed claims data from healthcare organizations throughout the United States. Included patients had a first diagnostic record of HES (ICD-10-CM D72.11) between January 1st 2022 and September 12th 2023 and had continuous 12-month enrollment prior to their first HES diagnosis (index date), with gaps of up to 45 days permitted. Patients were excluded if they had myeloprolifertive or secondary reactive variant of HES, or an eosinophilic granulomatosis with polyangiitis diagnosis after their HES diagnosis. Baseline was defined as the 12-month period prior to the index date, and Year 1 was defined as the 12-month period after the index date. Analyses were descriptive. Results: At the index date, patients with I-HES or L-HES (N=53) had a mean (standard deviation [SD]) age of 41.6 (21.4) years, with nine (17.0%) patients aged less than 18 years, 15 (28.3%) of Black or African American race, and 27 (50.9%) of White race. The proportion of males was 60.4% (n=32). Prior to receiving an I-HES or L-HES diagnosis, 47.2% of patients either had an asthma diagnosis or were receiving inhaled corticosteroids or short-acting β2-agonist treatment but without a diagnosis of chronic obstructive pulmonary disease. Other common morbidities prior to I-HES/L-HES diagnosis were dorsalgia (28.3%), gastroesophageal reflux disease (20.8%), and hypertensive disease (20.8%). Amongst eosinophilic conditions, unspecified eosinophilia was recorded in 35.8% of patients and eczema was recorded in 18.9% of patients. In patients at baseline (N=53) and during Year 1 (n=19), the mean (SD) number of organ systems with HES signs and/or symptoms was 3.2 (2.3) and 2.7 (1.8), respectively. At baseline, 15.1% and 37.7% of patients had 3 or ≥4 organ systems, respectively, with I-HES or L-HES signs and/or symptoms; during Year 1, the proportion of patients with 3 or ≥4 organ systems with I-HES or L-HES signs and/or symptoms was 31.6% each. At baseline, I-HES and L-HES signs, symptoms and morbidities were most prevalent in the pulmonary system (60.4%), followed by the ears, nose and throat (41.5%), cardiovascular (35.8%), gastrointestinal (34.0%), cardiac (30.2%), and cutaneous (30.2%) systems. Compared with baseline, the proportion of patients during Year 1 with I-HES or L-HES signs, symptoms and morbidities was slightly higher for the pulmonary (63.2%) and cutaneous (36.8%) systems, and lower in the ears, nose and throat (36.8%), cardiovascular (31.6%), gastrointestinal (21.1%), and cardiac (26.3%) systems. Common I-HES and L-HES signs, symptoms and morbidities at the index date included: runny nose (34.0%), chest pain (32.1%), cough (32.1%), asthma (30.2%), dyspnea (28.3%), abdominal pain (24.5%), arthralgia (22.6%), eczema (18.9%), and heart palpitations (18.9%). Conclusion: I-HES and L-HES were associated with multiple morbidities and organ system involvement, indicating a high disease burden at the time of diagnosis. While I-HES and L-HES are primarily hematological disorders of hypereosinophilia, many other clinical specialties may diagnose and manage patients with these disorders.

Background. Some patients who present with clinical features consistent with idiopathic hypereosinophilic syndrome (HES; absolute eosinophil count (AEC) ≥1.5 x 10 9/L with related end organ damage) are ultimately diagnosed with a myeloid neoplasm. Although FIP1L1::PDGFRA is the most common molecular abnormality in this setting, many other fusion genes, point mutations and cytogenetic abnormalities have been implicated in driving primary (neoplastic) eosinophilia. Given the poor prognosis of these disorders in the absence of treatment and the availability of targeted therapies for many of the driver mutations, it is becoming increasingly important to rapidly identify the underlying genetic alteration. In this regard, the expense and variable sensitivity of molecular diagnostic tests remains problematic. Although clinical features have been reported to distinguish between PDGFRA-associated myeloid neoplasms and D816V KIT-positive systemic mastocytosis with hypereosinophilia, little is known about the clinical phenotypes of other subsets of patients. This multicenter retrospective study aimed to assemble a large cohort of patients with HES secondary to a myeloid neoplasm to explore the utility of clinical and laboratory features in predicting the underlying molecular abnormality. Methods. Retrospective, de-identified data from 16 centers were collected via an online Research Electronic Data Capture repository. Patients and associated data were obtained from in-house research databases and/or electronic medical record searches at each site. Clinical and laboratory data were entered in accordance with local Institutional Review Boards. Inclusion criteria were peripheral blood hypereosinophilia (AEC &gt;1.5 x 10 9/L) on at least two occasions and one of the following: ≥1 confirmed genetic abnormality recurrently associated with primary myeloid neoplasms, other evidence of clonal eosinophilia, or increased blasts (≥2% in the blood or &gt;5% but &lt;20% in the marrow). Patients with acute myeloid leukemia were excluded. Results. A total of 277 patients followed between 1990 and 2022 were included in the analysis. Median length of follow up was 31 months (range &lt;1-356), and 217/277 (78%) were alive at last follow up. The most common genetic abnormality was FIP1L1::PDGFRA (n=131) followed by D816V KIT mutations (n=39) and alterations involving JAK2 (n=22) (Figure 1). Five patients had genetic abnormalities involving two distinct genes recurrently associated with eosinophilic myeloid neoplasms. The overall median age at diagnosis was 55 years (range 12-89) and 79% of the patients were male. When patients with abnormalities involving PDGFRA and PDGFRB were excluded from the analysis, the male predominance was significantly lower at 62% (p&lt;0.001, Fisher's exact test as compared to the data set as a whole). The overall pattern of organ system involvement was similar irrespective of the underlying genetic abnormality with a few notable exceptions. Cardiac involvement was most common in patients with FIP1L1:: PDGFRA, abnormalities involving JAK2 or without pathologic alterations identified (reported in 22%, 32% and 30%, respectively); whereas skin and gastrointestinal involvement, lymphadenopathy and splenomegaly were most frequent in patients with KIT D816V. Laboratory abnormalities also differed between groups. Whereas anemia was the most common blood abnormality (reported in &gt;50% of patients), erythrocytosis was noted primarily in patients with abnormalities involving JAK2. In contrast, circulating blasts were identified in 70% of patient with BCR::ABL1 and 29% of patients with chromosomal abnormalities or KIT D816V, but in &lt;15% of patients in any of the other groups. Whereas peak AEC alone did not discriminate between the different patient groups, the AEC/tryptase ratio was increased in patients with PDGFRA-associated myeloid neoplasms, molecular abnormalities involving JAK2, or chromosomal abnormalities as compared to those with KIT mutations (Figure 2). Conclusions. Despite the limitations of retrospective data analysis, the data from this large multicenter cohort of patients with HES due to a chronic myeloid neoplasm suggest that routine demographic, clinical and laboratory features vary depending on the underlying molecular abnormality. This approach could ultimately help guide empiric therapy when molecular studies are negative or unavailable.

Introduction Indolent systemic mastocytosis (ISM) is a rare clonal mast cell disease driven by the KIT D816V mutation in nearly all patients. Patients with ISM can present with debilitating acute and chronic cutaneous, gastrointestinal, neurocognitive, and systemic symptoms caused by the release of inflammatory mediators from abnormal mast cells. In some patients, symptoms are not adequately controlled with best supportive care (BSC) medications. Elenestinib (BLU-263) is a novel, investigational, oral, next-generation tyrosine kinase inhibitor that potently and selectively inhibits KIT D816V with limited central nervous system penetration and pharmacokinetics (PK) that support once daily dosing. HARBOR (NCT04910685) is a randomized, double-blind, placebo-controlled, phase 2/3 study assessing efficacy and safety of elenestinib in patients with ISM. Methods Eligible adult patients with ISM, confirmed following central review of bone marrow (BM) pathology, clinical, and laboratory findings per World Health Organization criteria and a moderate-to-severe symptom score based on minimum mean total symptom score (TSS) of the ISM-Symptom Assessment Form (ISM-SAF©2018), were stratified by baseline serum tryptase (&lt;20 ng/mL vs ≥20 ng/mL) and randomly assigned 3:1 to elenestinib 25 mg, 50 mg, or 100 mg once daily + BSC (“elenestinib”) or placebo + BSC (“placebo”). The primary objective of Part 1 was to determine the recommended dose based on safety, PK, and pharmacodynamics. Secondary endpoints included changes in biomarkers of disease burden (serum tryptase, KIT D816V variant allele fraction [VAF], and BM mast cells) and ISM-SAF TSS. Three additional open-label PK groups enrolled patients at 50 mg, 75 mg, and 100 mg to further characterize PK and safety. Results As of data cutoff on July 3, 2023, a total of 122 patients with ISM have received their assigned treatment in Part 1 of the study; 39 were blinded and randomized to elenestinib or placebo, and 83 were treated with open-label elenestinib in the PK groups (21 patients at 50 mg, 34 patients at 75 mg, and 28 patients at 100 mg). Baseline demographics were similar to those reported for the general ISM population. After 12 weeks of therapy, symptom improvement was observed for all dose cohorts, and symptom reduction by TSS was greater for patients on elenestinib versus placebo in the blinded portion of Part 1. Patients receiving elenestinib at 25 mg, 50 mg, and 100 mg doses showed reduction (mean percent) from baseline for tryptase (-15.4%, -50.9%, and -68.4% vs 3.3%, respectively) and KIT D816VVAF (-37.5%, -70.3%, and -77.0% vs -2.5%, respectively) as compared to placebo. Similar reductions in TSS and disease-related biomarkers were observed in the open-label PK cohorts. After a median treatment duration of 35.3 weeks, elenestinib was well-tolerated at all dose levels. There were no treatment-related serious adverse events and no treatment-related adverse events that led to drug discontinuation. Conclusion Elenestinib at all tested doses demonstrated beneficial effects on disease-related symptoms and biomarkers of mast cell burden in this large and maturing cohort of patients with ISM with a moderate-to-severe symptom burden. Elenestinib was well tolerated across all dose levels with a promising early benefit-risk profile in ISM. These preliminary findings will inform dosing for the planned Part 2 of HARBOR, which will examine elenestinib versus placebo in a randomized, blinded, placebo-controlled setting.

AbstractBackgroundHypereosinophilic syndrome (HES) encompasses a group of diseases with blood hypereosinophilia and eosinophil‐mediated organ dysfunction. HES‐associated skin abnormalities, termed cutaneous HES (cHES) here, may influence diagnosis of HES. We sought to better define clinical and histopathological features of cHES.MethodsWe retrospectively reviewed clinical records and cutaneous histopathology of adult patients with HES evaluated at our institution from 2007 to 2018.ResultsForty‐one percent (61/150) patients with HES had cHES. The most common clinical morphologies were urticarial (30%) and eczematous (26%). Skin specimens most often showed a spongiotic pattern (31%) with abundant inflammation (50%) including eosinophils (85%). Two specimens (8%) showed interstitial granulomatous dermatitis, and two specimens showed eosinophilic fasciitis (8%). Vasculitis was not identified in any specimen. Eighty‐four percent of patients with cHES had ≥1 other organ system involved: pulmonary 41%, ENT 26%, and nervous 23%. Sixty percent (53/89) of non‐cHES patients had at least two organ systems involved. Cardiac or gastrointestinal involvement was more common in non‐cHES than cHES (p < 0.05).ConclusionOur review confirms that there are no specific clinical or histopathological cHES patterns, but HES should be considered in patients who have eczematous or urticarial reactions of unknown etiology and persistent peripheral hypereosinophilia.