Ganz, Tomas

Abstract Approximately 17% of people aged 65 years and older are anemic, and 10% of death certificates report anemia as a secondary cause of death in the United States. Nonetheless, anemia remains unexplained in 30%-50% of older adults. This unexplained anemia of aging (UAA) is a diagnosis of exclusion. The mechanism, impact, and progression of UAA remain unknown. At older ages, anemia adds to pre-existing co-morbidities with significant adverse health consequences, representing a compelling unmet clinical concern. The National Institute on Aging held a workshop in 2024 to discuss current knowledge and research opportunities. Topics included the epidemiology of anemia at older age and its clinical implications; probable mechanism(s) underlying UAA, that is, low-grade inflammation’s effects on erythropoiesis; the role of microbiota in iron regulation in bone marrow; the importance of ruling out a diagnosis of leukemic clonal hematopoiesis (CH), which is more prevalent in older age; the role of senescence and aging governing hematopoiesis; and the effects of sex hormones on hematopoietic stem cell aging. Understanding the roles of these factors could reduce the proportion of the older anemic population whose anemia remains unexplained and offer insights into new potential diagnostic and intervention strategies. Speakers reviewed previous clinical trials in patients with UAA and CH. They discussed lessons learned and future research priorities, including efforts to develop new diagnostic algorithms and potential uses of machine learning.

Abstract We examined the bactericidal activity of two proteins that are abundant in the cytoplasmic granules of human eosinophils, major basic protein (MBP) and eosinophil cationic protein (ECP). Unlike the human neutrophil's peptide defensins, both MBP and ECP killed stationary phase Staphylococcus aureus 502A in a simple nutrient-free buffer solution. Although MBP also killed Escherichia coli ML-35 with considerable efficacy under these experimental conditions, the in vitro activity of ECP against E. coli was considerably enhanced if mid-logarithmic phase bacteria replaced stationary phase organisms or if the assay medium was enriched with trypticase soy broth. The antibacterial activity of both eosinophil proteins was modulated by incubation time, protein concentration, temperature and pH. A pBR322-transformed derivative of E. coli ML-35 was used to examine the effects of ECP and MBP on integrity of the bacterial inner membrane (IM) and outer membrane. Although both MBP and ECP caused outer and inner membrane permeabilization when nutrients were present, only MBP was effective under nutrient-free conditions. Two proton ionophores (DNP and carbonyl cyanide m-chlorophenyl hydrazone) protected E. coli from the bactericidal effects of ECP but not from MBP. These findings establish that MBP and ECP have bactericidal properties and suggest that these proteins kill E. coli by similar but nonidentical mechanisms marked by an attack on the target cell's membranes. In view of evidence that high concentrations of ECP and MBP exist in cytoplasmic granules whose contents are translocated to phagocytic vacuoles, we suggest that MBP and ECP contribute to the eosinophil's ability to kill ingested bacteria.

Abstract Momelotinib (MMB) is a JAK1/2 and ACVR1 inhibitor with demonstrated clinical activity in all 3 hallmarks of myelofibrosis (MF): anemia, constitutional symptoms, and splenomegaly. In this phase 2 open-label translational biology study (NCT02515630) of 41 transfusion-dependent patients with MF, we explored mechanisms underlying the favorable activity of MMB on MF-associated iron-restricted anemia, including its impact on serum hepcidin levels, and markers of iron storage and availability, erythropoiesis, and inflammation. A transfusion-independent response (TI-R), defined as red blood cell transfusion independence (TI) ≥12 weeks at any time on study, occurred in 17 patients (41%; 95% confidence interval [CI], 26%-58%), including 14 patients (34%; 95% CI, 20%-51%) who achieved TI-R by week 24. In addition, 78% of TI nonresponse (TI-NR) patients achieved a ≥50% decrease in transfusion requirement for ≥8 weeks. Adverse events (AEs) were consistent with previous studies of MMB in MF, with cough, diarrhea, and nausea as the most common. Twenty-one patients experienced grade ≥3 AEs, most commonly anemia and neutropenia. Consistent with preclinical data, daily MMB treatment led to an acute and persistent decrease in blood hepcidin associated with increased iron availability and markers of erythropoiesis. Baseline characteristics associated with TI-R were lower inflammation and hepcidin as well as increased markers of erythropoiesis and bone marrow function. Overall, the study demonstrates that MMB treatment decreases hepcidin in conjunction with improving iron metabolism and erythropoiesis, suggesting a mechanistic explanation for the reduced transfusion dependency observed in transfusion-dependent MF patients treated with MMB, thereby addressing the key unmet medical need in the MF population.

Abstract Introduction: Patients develop anemia as a result of myelofibrosis (MF) or its treatment, including Janus kinase (JAK) inhibitors. However, momelotinib (MMB), a JAK1/2 and Activin A receptor type I (ACVR1) inhibitor with demonstrated clinical activity in MF, improved anemia in prior clinical trials. JAK1/2 and ACVR1 respond to inflammation and iron stores to control iron availability through hepcidin, the key regulator of the entry of iron into circulation. Like other inflammatory diseases, MF is characterized by high hepcidin. MMB inhibited ACVR1 to modulate hepcidin and ameliorate anemia in a rodent model (Asshoff, Blood 2017). The impact of MMB was investigated on blood hepcidin, along with markers of iron storage and availability, erythropoiesis, and inflammation to explore mechanisms of the favorable effects of MMB on MF-associated anemia. Methods: In a phase 2 open-label study, MMB 200 mg once daily was given for 24 weeks to transfusion-dependent (TD; ≥4 units red blood cells [RBC] transfusion in the 8 weeks prior to first dose of MMB) patients with primary or post-ET/PV MF (age ≥18 yrs, required MF therapy, CrCl ≥ 60 mL/min, platelets ≥50 K, and absence of Gr ≥2 peripheral neuropathy, baseline palpable spleen was not required, patients with prior splenectomy were excluded). Patients were evaluated for MMB efficacy and safety. Total symptom score (TSS) was based on a modified Myeloproliferative Neoplasm Symptom Assessment Form. Transfusion-independent response/non-response (TI-R/NR) was defined as RBC transfusion-independence ≥12 weeks at any time on study. Serial blood samples were analyzed for a panel of biomarkers and liver iron content (LIC) was measured by MRI. Blood hepcidin was evaluated at every study visit in the morning (8-10am) pre-dose and 6 hours post-dose using a mass spectrometry assay and, prior to first dose, the normal daily increase of blood hepcidin was observed in half the population. Results: 41 patients (mean age 70, 63% male, 88% white) received MMB. By week 24, 14 (34.1%, 90% CI: 22.0-48.1%) patients had a TI-R and 39.0% had no RBC transfusion for ≥8 weeks at any time (90% CI: 26.2-53.1%). Six patients (15.8%, 90% CI: 7.1-28.8%) had a ≥50% reduction from baseline to week 24 in TSS and 5 patients (12.2%, 90% CI: 4.9-23.9%) had a ≥35% reduction in spleen volume; in those patients with week 24 data, the TSS and splenic response rates were 28.6% and 19.2% respectively. TSS and spleen volume assessments were not available for 17 (44.5%) and 15 (36.6%) patients, respectively, and these patients were considered non-responders. Adverse events were consistent with previous studies of MMB in MF, with cough, diarrhea, nausea, and fatigue as the most common. AEs ≥Gr 3 were experienced by 21 patients, most commonly anemia and neutropenia. At every study visit, median blood hepcidin decreased 6 hours after dosing with MMB (Fig. 1). Daily inhibition of hepcidin did not lead to an increase in serum iron for the entire population. However, serum iron, transferrin, hemoglobin, reticulocytes, and hematocrit increased at week 2 in patients with TI-R. Following this peak, serum iron decreased while hemoglobin, hematocrit and platelet count increased through week 24. At baseline, TI-R was associated with lower hepcidin, LIC, serum iron, reduced inflammation (C-reactive protein and ferritin), and higher hematocrit, erythrocytes, reticulocytes, platelets, and hemoglobin than TI-NR (Fig. 2). In multivariable analysis, TI-R was strongly associated with baseline hemoglobin ≥8g/dL (p=0.036) and lower morning hepcidin (p=0.013), weakly associated with younger age (p=0.070) and lower DIPSS score (p=0.075), but not with gender, type of MF (primary vs post-ET/PV), spleen volume, TSS, or JAK2V617F mutation. Conclusion: Safety findings and rate of TI-R were similar to TD MF patients in other MMB trials. Consistent with preclinical data, daily MMB treatment led to a transient decrease in blood hepcidin. In patients with TI-R, hepcidin suppression was associated with increased iron availability and markers of erythropoiesis. At baseline, TI-R associated with reduced inflammation, lower hepcidin, and increased markers of erythropoiesis and bone marrow function. Overall, the study suggests that transient modulation of hepcidin by MMB is sufficient to boost erythropoiesis in those transfusion-independent MF patients with lower baseline inflammation and greater erythropoietic potential. Disclosures Oh: Takeda: Research Funding; Janssen: Research Funding; CTI Biopharma: Research Funding; Gilead: Research Funding; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Gerds:Celgene: Consultancy; Apexx Oncology: Consultancy; CTI Biopharma: Consultancy; Incyte: Consultancy. Gupta:Novartis: Consultancy, Honoraria, Research Funding; Incyte: Research Funding. Verstovsek:Italfarmaco: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Incyte: Consultancy; Celgene: Membership on an entity's Board of Directors or advisory committees. Mesa:Novartis: Consultancy; Celgene: Research Funding; NS Pharma: Research Funding; Genentech: Research Funding; Incyte Corporation: Research Funding; Promedior: Research Funding; Pfizer: Research Funding; CTI Biopharma: Research Funding; Gilead: Research Funding; UT Health San Antonio - Mays Cancer Center: Employment. Miller:Gilead Sciences, Inc.: Consultancy, Research Funding; Incyte: Consultancy, Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria, Research Funding, Speakers Bureau. Heaney:Decipheral: Research Funding; Novartis: Research Funding; Blueprint: Research Funding; Incyte: Research Funding; Roche: Consultancy, Research Funding. O'Connell:Incyte: Research Funding. Arcasoy:Gilead Sciences, Inc.: Research Funding; Incyte: Research Funding; CTI BioPharma: Research Funding; Samus Therapeutics: Research Funding. Zhang:Gilead Sciences, Inc.: Employment. Kawashima:Gilead Sciences, Inc.: Employment, Equity Ownership. Ganz:Intrinsic LifeScience: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Silarus Pharma: Consultancy, Equity Ownership; Keryx Pharma: Consultancy, Research Funding; Akebia: Consultancy, Research Funding; Vifor: Consultancy; Gilead: Consultancy; Ablynx: Consultancy; La Jolla Pharma: Consultancy, Patents & Royalties: Patent licensed to La Jolla Pharma by UCLA. Baker Brachmann:Gilead Sciences, Inc.: Employment, Equity Ownership.