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Deferoxamine

Deferoxamine, also known as desferrioxamine B, is a naturally occurring and hexadentate iron-chelating agent derived from the bacterium pilosus, primarily used to treat chronic transfusional in patients with conditions such as thalassemia major and , as well as acute . It is included in the World Health Organization's List of Essential Medicines. It forms stable, water-soluble complexes with ferric iron and aluminum ions, facilitating their urinary and biliary excretion to reduce toxic metal accumulation in tissues. First approved by the U.S. in 1968 under the Desferal, deferoxamine mesylate is administered parenterally—typically via subcutaneous infusion for chronic therapy or intravenous/intramuscular routes for acute cases—and is available as a lyophilized for injection in 500 mg and 2 g vials. Chemically, deferoxamine has the molecular formula C25H48N6O8 and a molecular weight of 560.7 g/mol, functioning by binding free iron from labile pools, ferritin, and hemosiderin without affecting iron bound to transferrin, hemoglobin, or cytochromes. Its specificity for iron (and off-label for aluminum in chronic kidney disease) makes it an essential adjunct in managing transfusion-related hemosiderosis, where serum ferritin levels exceed 800–3000 ng/mL, though it is not a substitute for standard measures like phlebotomy in primary hemochromatosis. For chronic iron overload, dosing ranges from 20–60 mg/kg/day subcutaneously over 8–12 hours, while acute intoxication may require up to 15 mg/kg/hour intravenously, with careful monitoring to avoid exceeding daily limits of 6 g. Despite its efficacy, deferoxamine carries risks including auditory and ocular toxicities (e.g., and with prolonged use), growth suppression in children, and increased susceptibility to infections like or due to iron sequestration. It is contraindicated in severe renal impairment and anemic patients without , with precautions for rapid intravenous administration that can precipitate or . Recent has explored its off-label potential as a inhibitor and in radiation-induced tissue injury, highlighting its versatility beyond traditional .

Chemical and Physical Properties

Molecular Structure and Properties

Deferoxamine, also known as desferrioxamine B, has the C25H48N6O8 and a molecular weight of 560.7 g/mol. It features a linear trihydroxamic structure consisting of three hydroxamate groups (-N(OH)C(O)-) that enable metal , along with a terminal primary and repeating units of δ-N-acetyl-δ-N-hydroxy-L-ornithine connected via succinamide linkers. As a bacterial originally isolated from pilosus, deferoxamine exhibits a hexadentate for binding trivalent metal ions through its three bidentate hydroxamate moieties. Physically, it appears as a white to off-white crystalline powder with high in water (approximately 12 g/L at 20°C) and (about 21 g/L at 20°C), but it is practically insoluble in (less than 0.07 g/L). The hydroxamate groups have pKa values ranging from approximately 8.3 to 9.9, which affect its state, solubility, and efficiency at physiological pH. This structural arrangement confers a strong affinity for ferric iron, forming stable complexes essential for its therapeutic role.

Production and Synthesis

, also known as desferrioxamine B, was first isolated in the as a from bacterial cultures of pilosus, a actinomycete, during on iron-chelating compounds conducted by Ciba (now ) in . The compound was derived from ferrioxamine B by chemical removal of the iron atom, revealing its potential as a high-affinity trivalent iron chelator suitable for clinical applications. This discovery marked the initial step in its development as a pharmaceutical agent, with early studies confirming its production under iron-limited conditions in bacterial fermentation. Naturally, deferoxamine is biosynthesized by Streptomyces pilosus through a non-ribosomal synthetase (NRPS)-like pathway, serving as a for iron acquisition. The process begins with the of L-lysine to by lysine decarboxylase (encoded by desA), followed by to N-hydroxycadaverine via cadaverine monooxygenase (desB). These intermediates are then acylated with or by hydroxycadaverine acyltransferase (desC) to form δ-N-hydroxyornithine units, specifically N-hydroxy-N-succinylcadaverine (HSC) and N-hydroxy-N-acetylcadaverine (). The final assembly involves oligomerization of two HSC and one units by a multidomain synthetase (desD), yielding the linear hexahydroxamate structure of deferoxamine, with upregulated under via derepression of the des . Chemical synthesis of deferoxamine has evolved from early total syntheses to more efficient modular approaches. The first was reported in 1962 by Prelog and Walser, achieving a 6% over 11 steps but relying on harsh conditions. Subsequent methods, such as Bergeron's 1988 approach, improved but still involved toxic reagents. A 2024 mild modular strategy enables in 10 linear steps with 17% overall (or 13% via assistance), starting from divergent of N-hydroxycadaverine to generate protected HSC and monomers, followed by sequential amide couplings of hydroxamic acid building blocks using a Fukuyama-Mitsunobu installation and deprotection. In 2025, a chemoenzymatic approach was reported for directing the assembly of deferoxamine B using enzymatic to enhance . Earlier solid-phase methods have also been adapted for isopeptide analogs, facilitating analog synthesis through resin-bound assembly. Industrial production of deferoxamine primarily relies on of Streptomyces pilosus in iron-poor media, such as those supplemented with corn steep liquor to enhance yields. Post-fermentation, the broth is filtered at 5-8, and deferoxamine B is adsorbed onto weakly acidic cation exchange resins like AMBERLITE IRC-50, followed by with dilute ammonia or at low temperatures. Purification involves multistage on resins such as Diaion SP 207 or Amberlite XAD 1180, adjustment to 8.6-10.5 for precipitation, and conversion to the salt by treatment with in mixed solvents, yielding high-purity deferoxamine mesylate (>99.5%) suitable for pharmaceutical use after lyophilization. This process achieves up to 94.7% recovery while minimizing polyhydroxamate impurities to below 2.5 mole%.

Pharmacology

Mechanism of Action

Deferoxamine exerts its primary therapeutic action by chelating ferric iron (Fe³⁺) with exceptionally high affinity, characterized by a stability constant of log β ≈ 31. This binding forms the stable, octahedral ferrioxamine complex, in which the iron is coordinated by six oxygen atoms from the ligand's hydroxamate groups, rendering the metal unavailable for catalytic participation in the Fenton reaction and thereby mitigating and generation. The molecule achieves this through hexadentate coordination, utilizing three bidentate hydroxamate moieties that each contribute a pair of oxygen donors (one from the hydroxamate oxygen and one from the carbonyl oxygen) to envelop the Fe³⁺ ion in a rigid, cage-like . Deferoxamine also binds trivalent aluminum (Al³⁺) with lower (log β ≈ 23.9), forming the water-soluble aluminoxamine that promotes aluminum mobilization from tissues. By sequestering non-transferrin-bound iron (NTBI)—the labile plasma iron pool that accumulates in overload states—deferoxamine acts both extracellularly in the vasculature and intracellularly within cells, preventing iron-mediated damage and facilitating the urinary excretion of the ferrioxamine complex. In conditions, it exhibits secondary effects by modulating inflammatory pathways, such as inhibiting activation to reduce pro-inflammatory production, though it does not directly influence ferroportin-mediated iron export or regulation. At therapeutic concentrations, deferoxamine demonstrates high specificity for Fe³⁺ and Al³⁺, with minimal of essential divalent metals like (Zn²⁺) or (Cu²⁺), preserving physiological metal .

Pharmacokinetics

Deferoxamine exhibits route-dependent absorption characteristics. It is rapidly absorbed following intramuscular (IM) or subcutaneous (SC) administration, with peak plasma concentrations typically achieved within 0.5 to 1 hour. Oral bioavailability is poor, less than 1%, primarily due to enzymatic hydrolysis in the gastrointestinal tract. Intravenous (IV) administration provides immediate systemic exposure without absorption limitations. The drug distributes primarily in the , with a (Vd) of approximately 0.6 to 1.3 L/kg, indicating limited tissue penetration. Protein binding is low, less than 10% to proteins. Deferoxamine has limited penetration into the and does not readily cross the intact blood-brain barrier. Metabolism occurs mainly through enzymatic in and to a lesser extent in the liver, producing active , the predominant of which (metabolite B) accounts for about 85% of the administered dose and retains partial iron-chelating activity. Other metabolites include oxidative products that also possess chelating properties. Elimination is predominantly renal, with unmetabolized deferoxamine and its iron complex (ferrioxamine) excreted in , while the remainder is eliminated via through biliary ; approximately 50% of the dose appears in . The elimination is biphasic: an initial rapid phase of about 1 hour and a terminal phase of 3 to 6 hours for deferoxamine, with the ferrioxamine complex having a shorter half-life of 1 to 3 hours. Clearance is prolonged in patients with renal impairment. During chronic SC infusion for iron overload management, steady-state plasma concentrations of deferoxamine typically range from 1 to 5 μM, varying with patient iron burden and infusion regimen.

Clinical Applications

Indications

Deferoxamine is primarily indicated for the treatment of acute iron intoxication, where it serves as an adjunct to standard supportive measures to chelate and promote the excretion of free iron, thereby mitigating multi-organ failure from overdose. In cases of systemic toxicity, such as hemodynamic instability or with levels exceeding 500 mcg/dL, deferoxamine rapidly binds non-transferrin-bound iron to prevent cellular damage. For chronic iron overload associated with transfusion-dependent anemias, including β-thalassemia major and , deferoxamine is a standard therapy to reduce accumulated iron and avert complications like cardiac and hepatic . Regular use in these patients, initiated when serum exceeds 1000 ng/mL or liver iron concentration surpasses 3 mg Fe/g dry weight, promotes urinary and fecal iron excretion, slowing disease progression and improving cardiac function as measured by MRI T2* values. Long-term with deferoxamine has been associated with improved survival and reduced cardiac complications in patients, particularly by mitigating fatal . Randomized controlled trials demonstrate that chronic deferoxamine therapy achieves greater than 50% reduction in serum levels, establishing its efficacy in controlling iron burden. Deferoxamine is also used off-label for treating aluminum toxicity in patients with end-stage renal disease undergoing , where it chelates accumulated aluminum to alleviate , , and . This use targets serum aluminum levels above 20 mcg/L in chronic cases or over 200 mcg/L in , with post-infusion increases confirming tissue burden. In rare conditions like hemochromatosis and aceruloplasminemia, deferoxamine provides an alternative for iron removal when is contraindicated, though it is not first-line for primary hemochromatosis.

Administration and Dosage

Deferoxamine is administered via intramuscular (), intravenous (), or subcutaneous () routes, depending on the clinical scenario. IM administration is suitable for acute iron intoxication in patients not in shock, with doses not exceeding 2 g to avoid local reactions. IV infusion is preferred for severe acute poisoning or when rapid chelation is required, administered at a rate not exceeding 15 mg/kg/hour to prevent hypotension. For chronic iron overload, continuous SC infusion over 8-12 hours nightly using a portable pump is the standard approach, as deferoxamine exhibits poor oral absorption. For chronic iron overload due to transfusions, the recommended SC dose is 20–60 mg/kg/day, while IV dosing ranges from 40-50 mg/kg/day over 8-12 hours in adults, with a maximum daily dose of 6 g in adults and adjustments based on serum ferritin levels targeting below 1000 ng/mL to minimize toxicity. In acute iron poisoning, an initial IV dose of 15 mg/kg/hour is given until the urine turns red-brown (indicating ferrioxamine formation), followed by maintenance at 15 mg/kg/hour for up to 24 hours or until iron levels normalize, not exceeding 6 g in 24 hours. For aluminum toxicity in dialysis patients, a dose of 5 mg/kg/week is administered IV during the last hour of dialysis, with therapy guided by serum aluminum levels above 60 μg/L. Monitoring during deferoxamine therapy includes weekly serum ferritin assessments to guide dose adjustments and ensure therapeutic efficacy, alongside annual audiometry and ophthalmologic evaluations (including visual acuity, slit-lamp exams, and funduscopy) to detect potential sensory toxicities. Vitamin C supplementation, up to 200 mg/day in divided doses, should be avoided during the first month of therapy to prevent enhancing iron mobilization and cardiac risks, and introduced only after ferritin levels stabilize. In special populations, doses should be reduced in patients with renal impairment due to primary renal excretion of the deferoxamine-iron complex, with close monitoring of serum and urine output; deferoxamine is contraindicated in . There are limited human data on use during ; animal studies indicate potential for fetal harm. Use only if benefit justifies risk.

Safety Profile

Adverse Effects

Deferoxamine therapy is associated with a range of adverse effects, varying by administration route, dose, and duration of use. Local reactions at the injection site are among the most frequent, particularly with chronic , manifesting as , swelling, induration, and sterile abscesses in up to 80% of patients. These reactions are often dose-concentration dependent, exacerbated by solutions exceeding 10% concentration. Common systemic adverse effects include gastrointestinal disturbances such as (1-10%), with less common effects like and (0.1-1%), along with fever, leg cramps, and allergic rashes. These typically occur early in treatment and may resolve with continued use or dose adjustment. Sensory toxicities represent a significant concern in long-term therapy, with ototoxicity causing high-frequency in 20-40% of chronic users, and visual disturbances including night blindness, color vision defects, cataracts, and , which are dose-dependent and more prevalent at daily doses exceeding 50-60 mg/kg. Risk factors for these sensory effects include higher cumulative doses and low levels. Serious adverse effects, though less common, include hypotension during rapid intravenous infusion, anaphylaxis in less than 1% of cases, pulmonary toxicity such as acute respiratory distress syndrome with high-dose intravenous administration, growth retardation in pediatric patients, and increased susceptibility to Yersinia infections due to iron depletion enhancing bacterial growth. Chronic risks encompass neurotoxicity, particularly in patients with aluminum overload, and renal dysfunction, with higher incidence at doses greater than 50 mg/kg/day, particularly in patients with pre-existing impairment. These effects are linked to deferoxamine's renal excretion pathway, where accumulation can contribute to toxicity. Many adverse effects, especially sensory toxicities like hearing and visual impairments, are reversible upon discontinuation or dose reduction, though some chronic changes such as may persist partially in children. Regular monitoring, including audiometric and ophthalmologic evaluations, is essential to mitigate risks in prolonged . Guidelines recommend annual audiometric testing and ophthalmologic evaluations every 6-12 months during long-term .

Contraindications and Drug Interactions

Deferoxamine is contraindicated in patients with known to the drug, as it carries a risk of and severe allergic reactions. It is also contraindicated in individuals with severe renal failure or , given that both the drug and its iron chelate are primarily excreted by the kidneys, leading to potential accumulation and . Additionally, should be avoided in patients with active infections, as deferoxamine's iron-withholding effect can promote bacterial growth and exacerbate the infection. Relative precautions are advised for patients with renal or hepatic impairment, where dose reduction and close monitoring of organ function are recommended to mitigate risks of . In (FDA Category C), deferoxamine should be used only if the potential benefit outweighs the risk, due to limited human data and evidence of fetal skeletal anomalies and delayed in animal studies, with potential concerns. is not recommended during treatment and for at least one week after discontinuation, owing to the possibility of serious adverse reactions in the . Elderly patients require caution due to heightened sensitivity to sensory disturbances, such as and hearing impairments. Major drug interactions include concurrent use with vitamin C (ascorbic acid), which enhances iron mobilization and can precipitate cardiac decompensation in patients with ; supplementation should be delayed until at least one month after starting deferoxamine and limited to low doses (up to 200 mg/day in adults). , a , may increase the risk of and when combined with deferoxamine. Hydroxychloroquine can potentiate ocular toxicity, necessitating avoidance or careful monitoring. Deferoxamine has 37 known drug interactions, of which 22 are major and 15 moderate; notable examples include niacinamide ascorbate, which heightens cardiovascular risk. Concurrent administration with blood transfusions should be avoided to prevent misinterpretation of serum levels and infusion-related reactions. For interaction monitoring, ECG evaluation is essential when coadministering deferoxamine with certain antimalarials like due to the risk of prolongation. In dialysis patients, dosing adjustments are required for aluminum to optimize efficacy while minimizing toxicity.

History and Development

Discovery

Deferoxamine, known chemically as desferrioxamine B, was isolated in the late from cultures of the soil bacterium pilosus during a screening program for novel antibiotics at Ciba (now part of ) in , , conducted in collaboration with the Swiss Federal Institute of Technology in . The compound emerged serendipitously as researchers, led by Hans Bickel, investigated iron-containing metabolites like ferrimycins for their potential antibacterial activity, noting instead the strong iron-binding capabilities of a that functioned as a bacterial for iron acquisition and transport. This iron-free form, desferrioxamine B, was formally identified and described by Bickel and colleagues in , with its name derived from "des-ferri-oxamine," reflecting its role as an iron-depleted hydroxamate . By 1963, and team had elucidated its linear structure—a trihydroxamic acid chain—through chemical degradation and , confirming its hexadentate chelating potential for ferric iron. These efforts highlighted deferoxamine's specificity for Fe(III), distinguishing it from the antibiotic pursuits that initially uncovered it. Early preclinical investigations in the early 1960s demonstrated deferoxamine's efficacy in promoting iron excretion in animal models of overload, such as iron-loaded rabbits and dogs, where it safely increased urinary iron elimination without significant toxicity. These findings, building on the work of Bickel, Prelog, and associates like Ernst Gäumann and Wolfgang Keller-Schierlein, paved the way for initial human trials targeting transfusional iron overload in thalassemia patients by 1964.

Regulatory Approval and Milestones

Deferoxamine, marketed as Desferal by , received its initial approval from the (FDA) in 1968 for the treatment of acute iron intoxication and chronic due to transfusion-dependent anemias. It was first registered and marketed in in 1963. This marked the first regulatory endorsement of an iron chelator for clinical use in managing transfusional , particularly in conditions like thalassemia major. Early human trials demonstrating efficacy in iron-loaded patients began in the early , paving the way for this approval. The drug was first included on the World Health Organization's (WHO) Model List of Essential Medicines in 1979, specifically for treating transfusion-related , underscoring its global importance in resource-limited settings. In , deferoxamine gained marketing authorization in the 1970s through national agencies, prior to the establishment of the centralized procedure, enabling widespread adoption for . During the 1980s, its use expanded to include the management of aluminum toxicity in patients undergoing , although this remains an off-label indication in the United States; clinical guidelines and studies from that era supported its efficacy in reducing aluminum-related complications. Key milestones include the development of subcutaneous (SC) protocols using portable pumps in the , which significantly improved patient compliance by allowing home administration over 8-12 hours nightly, as recommended in contemporary management guidelines. In the , deferoxamine gained recognition for its potential cardioprotective role when used adjunctively with like , mitigating and through iron , though this application is supported by clinical studies rather than formal labeling expansions. The original patents for deferoxamine mesylate expired in the , leading to the availability of formulations, with the mesylate salt remaining the standard for injection; no major reformulations have been introduced by 2025. Globally, deferoxamine is produced by under the Desferal brand as well as various manufacturers, facilitating access primarily for patients with receiving lifelong .

Research and Future Directions

Ongoing Clinical Investigations

The DEFEAT-AKI trial (NCT04633889), a phase 2 randomized, double-blind, -controlled study, evaluated intravenous deferoxamine for preventing in patients undergoing by targeting iron-mediated . Completed by 2025, the trial involved prophylactic administration of deferoxamine and found it did not significantly reduce the incidence of compared to . Recent investigations into deferoxamine for , including a 2025 systematic review and of preclinical studies, demonstrate its potential to improve hindlimb motor function in animal models by mitigating secondary injury mechanisms such as . These preclinical efforts from 2024-2025 highlight the need for further clinical translation, though human trials remain limited, with early-phase explorations noting challenges in penetration for subcutaneous or intravenous dosing. Follow-up trials on deferoxamine for intracerebral hemorrhage, including a 2025 pilot double-blind randomized controlled study and an ongoing multicenter trial (NCT07162363) combining it with minimally invasive surgery, assess its role in improving neurological outcomes. In the pilot study, intravenous deferoxamine at 7.5 mg/kg per hour (maximum 6 g/day) for 3 days led to significant improvements in Glasgow Coma Scale scores within the first 4 days and reduced hematoma and edema volumes by approximately 20% on days 3 and 7 compared to placebo, alongside shorter hospital stays and lower mortality. The NCT07162363 trial, not yet recruiting as of late 2025, evaluates safety, feasibility, and efficacy of this combined approach in intracerebral hemorrhage patients. Studies on deferoxamine for sepsis-induced in 2025 primarily involve animal models, where it suppresses by reducing iron levels, , and markers like PTGS2 and ACSL4 while preserving and in cecal ligation and puncture models. Preclinical data confirm its potential to mitigate mitochondrial damage and in , with decreased (e.g., reduced IL-6 and TNF-α) and improved survival, though human phase I safety trials have not yet been reported in these contexts. A 2024-2025 of 73 patients with aluminum poisoning treated with weekly intramuscular deferoxamine at 5 / for 8 weeks demonstrated substantial aluminum reduction, with levels dropping below 60 /L in over 93% of cases from initial ranges of 60-200 /L, achieving more than 50% overall decrease and symptom resolution in most participants. A 2024 network meta-analysis of randomized controlled trials in transfusion-dependent anemias, including major, compared deferoxamine with and found similar efficacy in reducing liver iron concentration and levels. Oral deferasirox showed better patient compliance due to its administration route, while deferoxamine was associated with higher risks of sensory adverse effects, such as injection-site pain.

Emerging Therapeutic Applications

Recent preclinical studies have explored deferoxamine's potential in neuroprotection for Alzheimer's disease, focusing on its ability to chelate excess brain iron, which contributes to oxidative stress and protein aggregation. In mouse models of Alzheimer's, oral administration of deferoxamine from 2024 to 2025 reduced brain iron levels and downregulated iron signaling proteins, leading to decreased amyloid precursor protein processing and amyloid aggregation. These effects were accompanied by inhibition of iron-induced hippocampal tau phosphorylation, mitigating neurodegeneration and memory deficits in transgenic tau mice. Additionally, deferoxamine's limited blood-brain barrier penetration has prompted investigations into nanoparticle-based delivery systems, such as deferoxamine-conjugated liposomes, to enhance targeted chelation in the central nervous system while minimizing systemic exposure. In the realm of anti-aging research, network pharmacology analyses conducted in 2025 have highlighted deferoxamine's role in modulating key pathways within s. By chelating iron and reducing , deferoxamine activates the PI3K/AKT signaling pathway, promoting proliferation and attenuating markers like and β-. This mechanism enhances regenerative potential, suggesting applications in age-related tissue repair, with bioinformatics models predicting synergistic effects when combined with hypoxia-mimetic preconditioning to boost exosome secretion for paracrine anti-aging benefits. Preclinical data from 2025 indicate deferoxamine's utility in addressing iron dysregulation during , particularly in models. In rodent models of , deferoxamine restored iron homeostasis by suppressing , reducing and while preserving defenses, thereby mitigating liver damage and improving survival outcomes. The legacy of deferoxamine in research, stemming from post-2023 trials that showed no overall efficacy in moderately ill patients but tolerability in intensive care settings, continues to inform models of hyperinflammation driven by high levels. While randomized trials in 2024 confirmed neutral outcomes on viral clearance, theoretical insights suggest potential modulation by deferoxamine to reduce in diabetic subsets, providing insights into iron's role in persistent . As of November 2025, ongoing research explores deferoxamine's potential in sequelae, linking hyperferritinemia to persistent . Emerging links to models extend this, where deferoxamine's anti-ferroptotic effects in hyperferritinemic states alleviate multi-organ dysfunction, bridging sequelae to broader inflammatory syndromes. Innovations in deferoxamine delivery from 2022 to 2025 emphasize nanoparticle conjugation to overcome pharmacokinetic limitations, such as short and poor tissue targeting. Platelet membrane-coated s loaded with deferoxamine, developed in 2025, enable lesion-specific accumulation in ischemic or inflamed sites, significantly lowering required doses while enhancing iron efficiency and prolonging circulation. Carrier-free deferoxamine s and polymeric micelles further improve , reducing renal clearance and systemic toxicity, with preclinical showing up to threefold increases in area under the curve compared to free drug.