Kontoghiorghe Christina N, Kontoghiorghes George J
Postgraduate Research Institute of Science, Technology, Environment and Medicine, Limassol, Cyprus.
Drug Des Devel Ther. 2016 Jan 29;10:465-81. doi: 10.2147/DDDT.S79458. eCollection 2016.
The prevalence rate of thalassemia, which is endemic in Southeast Asia, the Middle East, and the Mediterranean, exceeds 100,000 live births per year. There are many genetic variants in thalassemia with different pathological severity, ranging from a mild and asymptomatic anemia to life-threatening clinical effects, requiring lifelong treatment, such as regular transfusions in thalassemia major (TM). Some of the thalassemias are non-transfusion-dependent, including many thalassemia intermedia (TI) variants, where iron overload is caused by chronic increase in iron absorption due to ineffective erythropoiesis. Many TI patients receive occasional transfusions. The rate of iron overloading in TI is much slower in comparison to TM patients. Iron toxicity in TI is usually manifested by the age of 30-40 years, and in TM by the age of 10 years. Subcutaneous deferoxamine (DFO), oral deferiprone (L1), and DFO-L1 combinations have been effectively used for more than 20 years for the treatment of iron overload in TM and TI patients, causing a significant reduction in morbidity and mortality. Selected protocols using DFO, L1, and their combination can be designed for personalized chelation therapy in TI, which can effectively and safely remove all the excess toxic iron and prevent cardiac, liver, and other organ damage. Both L1 and DF could also prevent iron absorption. The new oral chelator deferasirox (DFX) increases iron excretion and decreases liver iron in TM and TI. There are drawbacks in the use of DFX in TI, such as limitations related to dose, toxicity, and cost, iron load of the patients, and ineffective removal of excess iron from the heart. Furthermore, DFX appears to increase iron and other toxic metal absorption. Future treatments of TI and related iron-loading conditions could involve the use of the iron-chelating drugs and other drug combinations not only for increasing iron excretion but also for preventing iron absorption.
地中海贫血在东南亚、中东和地中海地区呈地方性流行，其每年的患病率超过10万例活产儿。地中海贫血存在许多具有不同病理严重程度的基因变异，从轻度无症状贫血到危及生命的临床影响不等，需要终身治疗，如重型地中海贫血（TM）需定期输血。部分地中海贫血类型无需依赖输血，包括许多中间型地中海贫血（TI）变异型，其铁过载是由于无效造血导致铁吸收慢性增加所致。许多TI患者偶尔接受输血。与TM患者相比，TI患者的铁过载速度要慢得多。TI患者的铁毒性通常在30 - 40岁时显现，而TM患者则在10岁时显现。皮下注射去铁胺（DFO）、口服地拉罗司（L1）以及DFO - L1联合用药已有效用于治疗TM和TI患者的铁过载20多年，显著降低了发病率和死亡率。可以设计使用DFO、L1及其联合用药的特定方案用于TI患者个性化螯合治疗，能有效且安全地清除所有过量的毒性铁，并预防心脏、肝脏和其他器官损伤。L1和DF都还能预防铁吸收。新型口服螯合剂地拉罗司（DFX）可增加TM和TI患者的铁排泄并降低肝脏铁含量。在TI患者中使用DFX存在一些缺点，如剂量、毒性和成本相关的限制、患者的铁负荷以及无法有效清除心脏中的过量铁。此外，DFX似乎会增加铁和其他有毒金属的吸收。未来TI及相关铁负荷病症的治疗可能不仅涉及使用铁螯合药物和其他药物组合来增加铁排泄，还涉及预防铁吸收。
