Luspatercept stimulates erythropoiesis, increases iron utilization, and redistributes body iron in transfusion-dependent thalassemia

Long-Term Experience with Luspatercept in Relapsed/Refractory Myelodysplastic Neoplasms: A Chinese Real-World Study

INTRODUCTION

Luspatercept has been shown to be efficacious for patients with relapsed or refractory lower-risk myelodysplastic neoplasms (LR-MDS) in both clinical trials and real-world studies. Nevertheless, long-term follow-up data in real-world settings remain scarce, particularly in Asia.

METHODS

Data from patients diagnosed with relapsed or refractory LR-MDS who had been treated with luspatercept at our center between June 2022 and May 2024 were retrospectively collected.

RESULTS

In total, 60 patients were included in this study (63.4% males). The median duration of luspatercept exposure was 9 (range 3-25) months, and the median follow-up time was 15 (range 3-26) months. The hematologic improvement-erythroid (HI-E) rate was 46.7%, 51.0%, 48.6%, and 43.3% at the 3rd, 6th, and 12th months, and at the end of follow-up, respectively. Among patients who were transfusion-dependent prior to luspatercept, 48.3%, 38.7%, and 25.8% achieved transfusion independence for 8, 12, and 16 weeks or longer at the 6th month. Over time, patients treated with luspatercept had a significant increase in hemoglobin level compared with that of the baseline from the 1st month to the end of follow-up (all P < 0.05). At the end of follow-up, 5 of 32 (15.6%) patients who had response had experienced a relapse, 1 patient (1.7%) had progressed to higher-risk myelodysplastic neoplasms (MDS), and 2 patients (3.3%) had progressed to acute myeloid leukemia. Three patients (5.0%) died of pulmonary infection. Serum erythropoietin (EPO) ≤ 500 IU/l at baseline was the only independent predictive factor for HI-E at the 3rd month (P = 0.007).

CONCLUSION

Luspatercept is proved efficacious and well tolerated in relapsed/refractory LR-MDS and appears to be beneficial in reducing disease progression and prolonging survival.

Best Practices in Gene Therapy for Sickle Cell Disease and Transfusion-dependent β-Thalassemia

Sickle cell disease (SCD) and transfusion-dependent β-thalassemia (TDT) are inherited blood disorders caused by pathogenic variants of the β-globin gene. Historically, allogeneic hematopoietic stem cell transplantation (HSCT) from human leukocyte antigen (HLA)-matched donors has been the only curative option. However, as most patients with SCD or TDT lack HLA-matched donors, autologous or patient-derived HSCT can provide an alternative, transformative option. Gene therapy-based autologous HSCT for the treatment of SCD and TDT entails a complex patient journey and requires the careful implementation of numerous policies and procedures. As gene therapies for these diseases are now commercially available, there is great value in institutions with developed and implemented approaches sharing their best practices. Here, we describe standardized approaches and best practices for the optimized implementation of gene therapies based on our experience in administering this novel class of medicines.

Long-term efficacy and safety of luspatercept for the treatment of anaemia in patients with transfusion-dependent β-thalassaemia (BELIEVE): final results from a phase 3 randomised trial

BACKGROUND

Treatments to reduce red blood cell (RBC) transfusion burden among patients with transfusion-dependent β-thalassaemia remain limited. Here, we report long-term follow-up data from the phase 3 BELIEVE trial of luspatercept for transfusion-dependent β-thalassaemia.

METHODS

BELIEVE was a phase 3, randomised, double-blind, placebo-controlled study performed at 65 sites in 15 countries. The trial included adults with transfusion-dependent β-thalassaemia or haemoglobin E/β-thalassaemia and Eastern Cooperative Oncology Group score of 0-1. Patients were randomly assigned (2:1) using integrated response technology stratified by region to luspatercept (1·0-1·25 mg/kg) or placebo administered subcutaneously once every 21 days. After study unblinding, patients could receive luspatercept in the open-label extension phase (crossover allowed). The primary endpoint results (proportion of patients with reduction in transfusion burden of ≥33% and ≥2 RBC units during weeks 13-24) are described elsewhere; herein we present an update to the primary endpoint analysis consequent to late-reported transfusion events. We also report long-term efficacy (intention-to-treat population) and safety data (safety population) for patients followed up for approximately 3 years. This trial is registered on ClinicalTrials.gov (NCT02604433) and is completed.

FINDINGS

Between May 2, 2016, and May 16, 2017, 336 patients were randomly assigned to luspatercept (n=224) or placebo (n=112). The median age of patients was 30 years (IQR 23-40); 195 (58%) were female and 141 (42%) male. As of Jan 5, 2021, the median duration of treatment in the luspatercept group was 153·6 weeks (IQR 81·0-171·0) and median study follow-up was 163·1 weeks (140·5-176·2). Due to the difference in treatment duration between the luspatercept and placebo groups, no comparative analyses between the two groups were performed after week 96. Patients in the luspatercept group showed a sustained reduction in RBC transfusion burden from baseline through week 192, with mean decreases of 6·2 RBC units (SD 5·7) during weeks 97-144 and 6·4 RBC units (4·3) during weeks 145-192. In the luspatercept group, a 33% or greater reduction in transfusion burden from baseline was observed in 173 (77%) patients over any 12-week interval and in 116 (52%) patients over any 24-week interval. The median total duration of 33% or greater transfusion burden reduction response during any period of at least 12 weeks was 586·0 days (IQR 264·0-1010·0). The most common grade 3 or worse treatment-emergent adverse events (TEAEs) among all patients who received luspatercept (n=315, including 92 patients who crossed over after study unblinding) were anaemia (nine [3%]), increased liver iron concentration (seven [2%]), and bone pain (seven [2%]); serious TEAEs occurred in 71 (23%) patients. No treatment-related deaths occurred in any group during the study.

INTERPRETATION

These long-term results affirm luspatercept's efficacy in addressing key unmet needs of patients with transfusion-dependent β-thalassaemia with a manageable safety profile.

FUNDING

Celgene and Acceleron Pharma.

Cardiac injury caused by iron overload in thalassemia

Cardiac iron overload affects approximately 25% of patients with β-thalassemia major, which is associated with increased morbidity and mortality. Two mechanisms are responsible for iron overload in β-thalassemia: increased iron absorption due to ineffective erythropoiesis and blood transfusions. This review examines the mechanisms of myocardial injury caused by cardiac iron overload and role of various clinical examination techniques in assessing cardiac iron burden and functional impairment. Early identification and intervention for cardiac injury and iron overload in β-thalassemia have the potential to prevent and reverse or delay its progression in the early stages, playing a crucial role in its prognosis.

Luspatercept: a treatment for ineffective erythropoiesis in thalassemia

Patients with β-thalassemia continue to have several unmet needs. In non-transfusion-dependent patients, untreated ineffective erythropoiesis and anemia have been associated with a variety of clinical sequelae, with no treatment currently available beyond supportive transfusions. In transfusion-dependent forms, lifelong transfusion and iron chelation therapy are associated with considerable clinical, psychological, and economic burden on the patient and health care system. Luspatercept is a novel disease-modifying agent targeting ineffective erythropoiesis that became recently available for patients with β-thalassemia. Data from randomized clinical trials confirmed its efficacy and safety in reducing transfusion burden in transfusion-dependent patients and increasing total hemoglobin level in non-transfusion-dependent patients. Secondary clinical benefits in patient-reported outcomes and iron overload were also observed on long-term therapy, and further data from real-world evidence studies are awaited.

Iron overload in acquired sideroblastic anemias and MDS: pathophysiology and role of chelation and luspatercept

Besides transfusion therapy, ineffective erythropoiesis contributes to systemic iron overload in myelodysplastic syndromes with ring sideroblasts (MDS-RS) via erythroferrone-induced suppression of hepcidin synthesis in the liver, leading to increased intestinal iron absorption. The underlying pathophysiology of MDS-RS, characterized by disturbed heme synthesis and mitochondrial iron accumulation, is less well understood. Several lines of evidence indicate that the mitochondrial transporter ABCB7 is critically involved. ABCB7 is misspliced and underexpressed in MDS-RS, due to somatic mutations in the splicing factor SF3B1. The pathogenetic significance of ABCB7 seems related to its role in stabilizing ferrochelatase, the enzyme incorporating iron into protoporphyrin IX to make heme. Although iron-related oxidative stress is toxic, many patients with MDS do not live long enough to develop clinical complications of iron overload. Furthermore, it is difficult to determine the extent to which iron overload contributes to morbidity and mortality in older patients with MDS, because iron-related complications overlap with age-related medical problems. Nevertheless, high-quality registry studies showed that transfusion dependency is associated with the presence of toxic iron species and inferior survival and confirmed a significant survival benefit of iron chelation therapy. The most widely used iron chelator in patients with MDS is deferasirox, owing to its effectiveness and convenient oral administration. Luspatercept, which can reduce SMAD2/SMAD3-dependent signaling implicated in suppression of erythropoiesis, may obviate the need for red blood cell transfusion in MDS-RS for more than a year, thereby diminishing further iron loading. However, luspatercept cannot be expected to substantially reduce the existing iron overload.

Impact of met-haemoglobin and oxidative stress on endothelial function in patients with transfusion dependent β-thalassemia

Transfusion dependent β-thalassemia is a genetic blood disorder characterized by chronic anaemia. Blood transfusion is lifesaving but comes at a cost. Iron overload emerges as a prime culprit as a free radicals damage endothelial cells. Chronic anaemia further disrupts oxygen delivery, exacerbating the oxidative stress. Increased levels of met-haemoglobin and malondialdehyde compromise endothelial function. This research sheds light on the impact of met-haemoglobin and oxidative stress on endothelial function in 50 patients with transfusion dependent β-thalassemia major compared to 50 healthy individuals as control. Blood samples were collected & subjected to CBC, biochemical analysis including creatinine, ferritin, CRP, LDH, and HCV antibodies. Oxidative stress was assessed using met-haemoglobin & malondialdehyde. Endothelial dysfunction was evaluated by endothelial activation and stress index (EASIX). EASIX, met-haemoglobin and malondialdehyde were significantly increased in patients (1.44 ± 0.75, 2.07 ± 0.2, 4.8 ± 0.63; respectively) compared to the control (0.52 ± 0.24,0.88 ± 0.34,0.8 ± 0.34; respectively). Significant strong positive correlation was found between EASIX and met-haemoglobin, malondialdehyde, serum ferritin and CRP (P = 0.00, r = 0.904, P = 0.00, r = 0.948, P = 0.00, r = 0.772, P = 0.00, r = 0.971; respectively. Met-haemoglobin as well as EASIX should be routinely estimated to assess endothelial function especially before the decision of splenectomy. Antioxidant drugs should be supplemented.

Combination of a TGF-β ligand trap (RAP-GRL) and TMPRSS6-ASO is superior for correcting β-thalassemia

A recently approved drug that induces erythroid cell maturation (luspatercept) has been shown to improve anemia and reduce the need for blood transfusion in non-transfusion-dependent as well as transfusion-dependent β-thalassemia (BT) patients. Although these results were predominantly positive, not all the patients showed the expected increase in hemoglobin (Hb) levels or transfusion burden reduction. Additional studies indicated that administration of luspatercept in transfusion-dependent BT was associated with increased erythropoietic markers, decreased hepcidin levels, and increased liver iron content. Altogether, these studies suggest that luspatercept may necessitate additional drugs for improved erythroid and iron management. As luspatercept does not appear to directly affect iron metabolism, we hypothesized that TMPRSS6-ASO could improve iron parameters and iron overload when co-administered with luspatercept. We used an agent analogous to murine luspatercept (RAP-GRL) and another novel therapeutic, IONIS TMPRSS6-LRx (TMPRSS6-ASO), a hepcidin inducer, to treat non-transfusion-dependent BT-intermedia mice. Our study shows that RAP-GRL alone improved red blood cell (RBC) production, with no or limited effect on splenomegaly and iron parameters. In contrast, TMPRSS6-ASO improved RBC measurements, ameliorated splenomegaly, and improved iron overload most effectively. Our results provide pre-clinical support for combining TMPRSS6-ASO and luspatercept in treating BT, as these drugs together show potential for simultaneously improving both erythroid and iron parameters in BT patients.

Molecular Pathways Governing the Termination of Liver Regeneration

The liver has the unique capacity to regenerate, and up to 70% of the liver can be removed without detrimental consequences to the organism. Liver regeneration is a complex process involving multiple signaling networks and organs. Liver regeneration proceeds through three phases: the initiation phase, the growth phase, and the termination phase. Termination of liver regeneration occurs when the liver reaches a liver-to-body weight that is required for homeostasis, the so-called "hepatostat." The initiation and growth phases have been the subject of many studies. The molecular pathways that govern the termination phase, however, remain to be fully elucidated. This review summarizes the pathways and molecules that signal the cessation of liver regrowth after partial hepatectomy and answers the question, "What factors drive the hepatostat?" SIGNIFICANCE STATEMENT: Unraveling the pathways underlying the cessation of liver regeneration enables the identification of druggable targets that will allow us to gain pharmacological control over liver regeneration. For these purposes, it would be useful to understand why the regenerative capacity of the liver is hampered under certain pathological circumstances so as to artificially modulate the regenerative processes (e.g., by blocking the cessation pathways) to improve clinical outcomes and safeguard the patient's life.

The Importance and Essentiality of Natural and Synthetic Chelators in Medicine: Increased Prospects for the Effective Treatment of Iron Overload and Iron Deficiency

The supply and control of iron is essential for all cells and vital for many physiological processes. All functions and activities of iron are expressed in conjunction with iron-binding molecules. For example, natural chelators such as transferrin and chelator-iron complexes such as haem play major roles in iron metabolism and human physiology. Similarly, the mainstay treatments of the most common diseases of iron metabolism, namely iron deficiency anaemia and iron overload, involve many iron-chelator complexes and the iron-chelating drugs deferiprone (L1), deferoxamine (DF) and deferasirox. Endogenous chelators such as citric acid and glutathione and exogenous chelators such as ascorbic acid also play important roles in iron metabolism and iron homeostasis. Recent advances in the treatment of iron deficiency anaemia with effective iron complexes such as the ferric iron tri-maltol complex (feraccru or accrufer) and the effective treatment of transfusional iron overload using L1 and L1/DF combinations have decreased associated mortality and morbidity and also improved the quality of life of millions of patients. Many other chelating drugs such as ciclopirox, dexrazoxane and EDTA are used daily by millions of patients in other diseases. Similarly, many other drugs or their metabolites with iron-chelation capacity such as hydroxyurea, tetracyclines, anthracyclines and aspirin, as well as dietary molecules such as gallic acid, caffeic acid, quercetin, ellagic acid, maltol and many other phytochelators, are known to interact with iron and affect iron metabolism and related diseases. Different interactions are also observed in the presence of essential, xenobiotic, diagnostic and theranostic metal ions competing with iron. Clinical trials using L1 in Parkinson's, Alzheimer's and other neurodegenerative diseases, as well as HIV and other infections, cancer, diabetic nephropathy and anaemia of inflammation, highlight the importance of chelation therapy in many other clinical conditions. The proposed use of iron chelators for modulating ferroptosis signifies a new era in the design of new therapeutic chelation strategies in many other diseases. The introduction of artificial intelligence guidance for optimal chelation therapeutic outcomes in personalised medicine is expected to increase further the impact of chelation in medicine, as well as the survival and quality of life of millions of patients with iron metabolic disorders and also other diseases.

Pollutants to pathogens: The role of heavy metals in modulating TGF-β signaling and lung cancer risk

Lung cancer is a malignant tumor that develops in the lungs due to the uncontrolled growth of aberrant cells. Heavy metals, such as arsenic, cadmium, mercury, and lead, are metallic elements characterized by their high atomic weights and densities. Anthropogenic activities, such as industrial operations and pollution, have the potential to discharge heavy metals into the environment, hence presenting hazards to ecosystems and human well-being. The TGF-β signalling pathways have a crucial function in controlling several cellular processes, with the ability to both prevent and promote tumor growth. TGF-β regulates cellular responses by interacting in both canonical and non-canonical signalling pathways. Research employing both in vitro and in vivo models has shown that heavy metals may trigger TGF-β signalling via complex molecular pathways. Experiments conducted in a controlled laboratory environment show that heavy metals like cadmium and arsenic may directly bind to TGF-β receptors, leading to alterations in their structure that enable the receptor to be phosphorylated. Activation of this route sets in motion subsequent signalling cascades, most notably the canonical Smad pathway. The development of lung cancer has been linked to heavy metals, which are ubiquitous environmental pollutants. To grasp the underlying processes, it is necessary to comprehend their molecular effect on TGF-β pathways. With a particular emphasis on its consequences for lung cancer, this abstract delves into the complex connection between exposure to heavy metals and the stimulation of TGF-β signalling.