Non-Transfusion-Dependent Thalassemia: An Update on Complications and Management

Patients with non-transfusion-dependent thalassemia (NTDT) experience many clinical complications despite their independence from frequent transfusions. Morbidities in NTDT stem from the interaction of multiple pathophysiological factors: ineffective erythropoiesis, iron overload (IOL), and hypercoagulability. Ineffective erythropoiesis and hemolysis are associated with chronic hypoxia and a hypercoagulable state. The latter are linked to a high prevalence of thromboembolic and cerebrovascular events, as well as leg ulcers and pulmonary hypertension. IOL in NTDT patients is a cumulative process that can lead to several iron-related morbidities in the liver (liver fibrosis), kidneys, endocrine glands (endocrinopathies), and vascular system (vascular disease). This review sheds light on the pathophysiology underlying morbidities associated with NTDT and summarizes the mainstays of treatment and some of the possible future therapeutic interventions

Does Race Play a Role in Complications and Outcomes of Philadelphia Chromosome-Negative Myeloproliferative Neoplasms?

BACKGROUND: Philadelphia chromosome-negative myeloproliferative neoplasms (MPN) are a group of hematologic malignancies with known vascular complications. The role race and ethnicity play in these complications is less defined. We aimed to further evaluate the role of race in patients without a history of previous thrombotic or hemorrhagic events. METHODS: In this retrospective study, 300 adult patients with MPN were included; 270 (90.0%) were White and 30 (10.0%) were non-White. The non-White group primarily consisted of African American or Black (26 patients), followed by others. Median age at diagnosis was 58 years for White patients and 61.5 years for non-White patients. The interaction between outcomes and vascular events with race was evaluated using multivariate logistical regression models. RESULTS: The incidence of thrombotic events was inversely correlated with age at diagnosis, with younger patients demonstrating a higher rate of thrombotic events over time (p < .001). The incidence of thrombotic or hemorrhagic events did not differ between White and non-White patients. A statistically significant difference in median survival was observed between White and non-White patients: 29 years (95% confidence interval [CI]: 21.8-not reached) versus 13 years (95% CI: 5.7-22.7), respectively (p = .016). CONCLUSION: This study did not find a significant difference in the rate of thrombotic or hemorrhagic events between White and non-White patients with MPN but suggested that non-White patients had significantly shorter median survival than White patients. Such observations may inform future studies to further characterize racial disparities in outcomes

Iron overload in thalassemia: different organs at different rates

Thalassemic disorders lie on a phenotypic spectrum of clinical severity that depends on the severity of the globin gene mutation and coinheritance of other genetic determinants. Iron overload is associated with increased morbidity in both patients with transfusion-dependent thalassemia (TDT) and non-transfusion-dependent thalassemia (NTDT). The predominant mechanisms driving the process of iron loading include increased iron burden secondary to transfusion therapy in TDT and enhanced intestinal absorption secondary to ineffective erythropoiesis and hepcidin suppression in NTDT. Different organs are affected differently by iron overload in TDT and NTDT owing to the underlying iron loading mechanism and rate of iron accumulation. Serum ferritin measurement and noninvasive imaging techniques are available to diagnose iron overload, quantify its extent in different organs, and monitor clinical response to therapy. This chapter discusses the general approach to iron chelation therapy based on organ involvement using the available iron chelators: deferoxamine, deferiprone, and deferasirox. Other novel experimental options for treatment and prevention of complications associated with iron overload in thalassemia are briefly discussed

Resistance to venetoclax and hypomethylating agents in acute myeloid leukemia

Despite the success of the combination of venetoclax with the hypomethylating agents (HMA) decitabine or azacitidine in inducing remission in older, previously untreated patients with acute myeloid leukemia (AML), resistance - primary or secondary - still constitutes a significant roadblock in the quest to prolong the duration of response. Here we review the proposed and proven mechanisms of resistance to venetoclax monotherapy, HMA monotherapy, and the doublet of venetoclax and HMA for the treatment of AML. We approach the mechanisms of resistance to HMAs and venetoclax in the light of the agents’ mechanisms of action. We briefly describe potential therapeutic strategies to circumvent resistance to this promising combination, including alternative scheduling or the addition of other agents to the HMA and venetoclax backbone. Understanding the mechanisms of action and evolving resistance in AML remains a priority in order to maximize the benefit from novel drugs and combinations, identify new therapeutic targets, define potential prognostic markers, and avoid treatment failure

Non-transfusion dependent thalassemia: translating evidence to guidelines

The thalassemias are a group of inherited disorders of hemoglobin synthesis characterized by various degrees of defective production of the α- or β-globin chains of adult hemoglobin A. Non-transfusion- dependent thalassemia (NTDT) includes a group of thalassemia patients who do not require regular RBC transfusions for survival, but may require occasional transfusions due to infection or pregnancy or may require more regular transfusions later in life due to splenomegaly or other complications. Due to the rising phenomenon of global migration, this previously well-localized entity is currently spreading more and more worldwide reaching Northern America and Northern Europe. The clinical picture of NTDT is governed by the severity of the ineffective erythropoiesis and the chronic hemolytic anemia, which, in turn, lead to iron overload, hypercoagulability, and an array of clinical complications involving almost every organ system. Patients with NTDT suffer from complications that are distinct from those encountered in patients with transfusion- dependent thalassemia (TDT) in addition to the complications shared by both TDT and NTDT. As a consequence, patients with NTDT deserve a care specifically tailored to their needs. In the care of patients with NTDT, aiming at a standardized yet personalized care is not an easy task especially that NTDT patients lie on a heterogeneous spectrum with a wide variability in their clinical presentation and response to therapy. Therefore, guidelines emerge as a necessity to answer the specific needs of NTDT patients and the clinicians caring for them. In this article, we summarize the complications most commonly associated with NTDT and the recommendations of the guidelines for the management of patients with NTDT, based on the best available evidence

PARP Inhibitors and Myeloid Neoplasms: A Double-Edged Sword

Despite recent discoveries and therapeutic advances in aggressive myeloid neoplasms, there remains a pressing need for improved therapies. For instance, in acute myeloid leukemia (AML), while most patients achieve a complete remission with conventional chemotherapy or the combination of a hypomethylating agent and venetoclax, de novo or acquired drug resistance often presents an insurmountable challenge, especially in older patients. Poly(ADP-ribose) polymerase (PARP) enzymes, PARP1 and PARP2, are involved in detecting DNA damage and repairing it through multiple pathways, including base excision repair, single-strand break repair, and double-strand break repair. In the context of AML, PARP inhibitors (PARPi) could potentially exploit the frequently dysfunctional DNA repair pathways that, similar to deficiencies in homologous recombination in BRCA-mutant disease, set the stage for cell killing. PARPi appear to be especially effective in AML with certain gene rearrangements and molecular characteristics (RUNX1-RUNX1T1 and PML-RARA fusions, FLT3- and IDH1-mutated). In addition, PARPi can enhance the efficacy of other agents, particularly alkylating agents, TOP1 poisons, and hypomethylating agents, that induce lesions ordinarily repaired via PARP1-dependent mechanisms. Conversely, emerging reports suggest that long-term treatment with PARPi for solid tumors is associated with an increased incidence of myelodysplastic syndrome (MDS) and AML. Here, we (i) review the pre-clinical and clinical data on the role of PARPi, specifically olaparib, talazoparib, and veliparib, in aggressive myeloid neoplasms and (ii) discuss the reported risk of MDS/AML with PARPi, especially as the indications for PARPi use expand to include patients with potentially curable cancer