Fulminant Liver Failure in a Child With β-Thalassemia on Deferasirox: A Case Report

Drug Selection and Posology, Optimal Therapies and Risk/Benefit Assessment in Medicine: The Paradigm of Iron-Chelating Drugs

The design of clinical protocols and the selection of drugs with appropriate posology are critical parameters for therapeutic outcomes. Optimal therapeutic protocols could ideally be designed in all diseases including for millions of patients affected by excess iron deposition (EID) toxicity based on personalised medicine parameters, as well as many variations and limitations. EID is an adverse prognostic factor for all diseases and especially for millions of chronically red-blood-cell-transfused patients. Differences in iron chelation therapy posology cause disappointing results in neurodegenerative diseases at low doses, but lifesaving outcomes in thalassemia major (TM) when using higher doses. In particular, the transformation of TM from a fatal to a chronic disease has been achieved using effective doses of oral deferiprone (L1), which improved compliance and cleared excess toxic iron from the heart associated with increased mortality in TM. Furthermore, effective L1 and L1/deferoxamine combination posology resulted in the complete elimination of EID and the maintenance of normal iron store levels in TM. The selection of effective chelation protocols has been monitored by MRI T2* diagnosis for EID levels in different organs. Millions of other iron-loaded patients with sickle cell anemia, myelodysplasia and haemopoietic stem cell transplantation, or non-iron-loaded categories with EID in different organs could also benefit from such chelation therapy advances. Drawbacks of chelation therapy include drug toxicity in some patients and also the wide use of suboptimal chelation protocols, resulting in ineffective therapies. Drug metabolic effects, and interactions with other metals, drugs and dietary molecules also affected iron chelation therapy. Drug selection and the identification of effective or optimal dose protocols are essential for positive therapeutic outcomes in the use of chelating drugs in TM and other iron-loaded and non-iron-loaded conditions, as well as general iron toxicity.

What are the clues for an inherited metabolic disorder in Reye syndrome? A single Centre study of 58 children

OBJECTIVES

Reye Syndrome is an acute encephalopathy with increased liver enzymes and blood ammonia, without jaundice. The prevalence of an underlying inherited metabolic disorder (IMD) is unclear, nor the clinical or biological factors directing toward this diagnosis. Our aims were to define these clues in a large series of patients.

PATIENTS AND METHODS

We retrospectively studied all patients with Reye admitted in our institution from 1995. We defined 3 groups: Group 1 with a confirmed IMD, Group 2 considered as free of IMD, Group 3 unclassified. Statistical analysis compared patients in Groups 1 and 2, to find criteria for a diagnosis of IMD.

RESULTS

Fifty-eight children were included; 41 (71%) had a confirmed IMD, 12 (20%) were free of IMD, and 5 remained unclassified. IMDs included Urea Cycle Disorders (51%), Fatty-Acid Oxidation Disorders (24%), ketogenesis defects (5%), other mitochondrial energy metabolism defects (10%), NBAS mutation (7%), Glycosylation Disorders (2%). In Group 2, the trigger was a viral infection, or a drug, deferasirox in three children. Univariate analysis showed that onset before 2 years-old, recurrent Reye and the association with rhabdomyolysis were significantly associated with IMD. Blood ammonia was a poor discriminating marker. All children were admitted into the intensive care unit, 23% needed continuous venovenous hemodialysis and one died from brain oedema.

CONCLUSION

Metabolic tests should be performed early in all cases of Reye, regardless of triggers. As they can be inconclusive, we suggest to systematically go to Next-Generation Sequencing study. These children should be transferred early to a specialized unit.

The Impact of Iron Chelators on the Biology of Cancer Stem Cells

Neoplastic diseases are still a major medical challenge, requiring a constant search for new therapeutic options. A serious problem of many cancers is resistance to anticancer drugs and disease progression in metastases or local recurrence. These characteristics of cancer cells may be related to the specific properties of cancer stem cells (CSC). CSCs are involved in inhibiting cells’ maturation, which is essential for maintaining their self-renewal capacity and pluripotency. They show increased expression of transcription factor proteins, which were defined as stemness-related markers. This group of proteins includes OCT4, SOX2, KLF4, Nanog, and SALL4. It has been noticed that the metabolism of cancer cells is changed, and the demand for iron is significantly increased. Iron chelators have been proven to have antitumor activity and influence the expression of stemness-related markers, thus reducing chemoresistance and the risk of tumor cell progression. This prompts further investigation of these agents as promising anticancer novel drugs. The article presents the characteristics of stemness markers and their influence on the development and course of neoplastic disease. Available iron chelators were also described, and their effects on cancer cells and expression of stemness-related markers were analyzed.

Kidney Tubular Damage Secondary to Deferasirox: Systematic Literature Review

Deferasirox is a first-line therapy for iron overload that can sometimes cause kidney damage. To better define the pattern of tubular damage, a systematic literature review was conducted on the United States National Library of Medicine, Excerpta Medica, and Web of Science databases. Twenty-three reports describing 57 individual cases could be included. The majority (n = 35) of the 57 patients were ≤18 years of age and affected by thalassemia (n = 46). Abnormal urinary findings were noted in 54, electrolyte or acid–base abnormalities in 46, and acute kidney injury in 9 patients. Latent tubular damage was diagnosed in 11 (19%), overt kidney tubular damage in 37 (65%), and an acute kidney injury in the remaining nine (16%) patients. Out of the 117 acid–base and electrolyte disorders reported in 48 patients, normal-gap metabolic acidosis and hypophosphatemia were the most frequent. Further abnormalities were, in decreasing order of frequency, hypokalemia, hypouricemia, hypocalcemia, and hyponatremia. Out of the 81 abnormal urinary findings, renal glucosuria was the most frequent, followed by tubular proteinuria, total proteinuria, and aminoaciduria. In conclusion, a proximal tubulopathy pattern may be observed on treatment with deferasirox. Since deferasirox-associated kidney damage is dose-dependent, physicians should prescribe the lowest efficacious dose.

The Cross-Link between Ferroptosis and Kidney Diseases

Acute and chronic kidney injuries result from structural dysfunction and metabolic disorders of the kidney in various etiologies, which significantly affect human survival and social wealth. Nephropathies are often accompanied by various forms of cell death and complex microenvironments. In recent decades, the study of kidney diseases and the traditional forms of cell death have improved. Nontraditional forms of cell death, represented by ferroptosis and necroptosis, have been discovered in the field of kidney diseases, which have reshuffled the role of traditional cell death in nephropathies. Although interactions between ferroptosis and acute kidney injury (AKI) have been continuously explored, studies on ferroptosis and chronic kidney disease (CKD) remain limited. Here, we have reviewed the therapeutic significance of ferroptosis in AKI and anticipated the curative potential of ferroptosis for CKD in the hope of providing insights into ferroptosis and CKD.

Deferasirox-induced liver injury and Fanconi syndrome in a beta-thalassemia major male

A 33-year-old male presenting with subacute abdominal pain was found to have hyperbilirubinaemia, hypokalaemia and hyponatraemia. This was in the setting of transitioning between deferasirox iron chelator formulations, from dispersible tablets to film-coated tablets for ongoing treatment of chronic iron overload secondary to transfusion requirement for beta-thalassemia major. A liver biopsy demonstrated acute cholestasis with patchy confluent hepatocellular necrosis and mild to moderate microvesicular steatosis. Based on the histological, biochemical and clinical findings, the diagnosis of hepatotoxicity and Fanconi-like syndrome was made. The patient improved clinically and biochemically with cessation of the deferasirox film-coated tablets and supportive management. To our knowledge, this is the first case report of hepatotoxicity and Fanconi-like syndrome occurring due to deferasirox film-coated tablets with previous tolerance of dispersible deferasirox tablets. It is important to raise clinical awareness of this potentially severe complication.

The iron chelator Deferasirox causes severe mitochondrial swelling without depolarization due to a specific effect on inner membrane permeability

The iron chelator Deferasirox (DFX) causes severe toxicity in patients for reasons that were previously unexplained. Here, using the kidney as a clinically relevant in vivo model for toxicity together with a broad range of experimental techniques, including live cell imaging and in vitro biophysical models, we show that DFX causes partial uncoupling and dramatic swelling of mitochondria, but without depolarization or opening of the mitochondrial permeability transition pore. This effect is explained by an increase in inner mitochondrial membrane (IMM) permeability to protons, but not small molecules. The movement of water into mitochondria is prevented by altering intracellular osmotic gradients. Other clinically used iron chelators do not produce mitochondrial swelling. Thus, DFX causes organ toxicity due to an off-target effect on the IMM, which has major adverse consequences for mitochondrial volume regulation.

Measurement of the liver iron concentration in transfusional iron overload by MRI R2* and by high-transition-temperature superconducting magnetic susceptometry

PURPOSE

To compare measurement of the liver iron concentration in patients with transfusional iron overload by magnetic resonance imaging (MRI), using R2*, and by magnetic susceptometry, using a new high-transitiontemperature (high-Tc; operating at 77 K, cooled by liquid nitrogen) superconducting magnetic susceptometer.

METHODS

In 28 patients with transfusional iron overload, 43 measurements of the liver iron concentration were made by both R2* and high-Tc magnetic susceptometry.

RESULTS

Measurements of the liver iron concentration by R2* and high-Tc magnetic susceptometry were significantly correlated when comparing all patients (Pearson's r = 0.91, p < 0.0001) and those with results by susceptometry >7 mg Fe/g liver, dry weight (r = 0.93, p = 0.006). In lower ranges of liver iron, no significant correlations between the two methods were found (0 to <3.2 mg Fe/g liver, dry weight: r = 0.2, p = 0.37; 3.2 to 7 mg Fe/g liver, dry weight: r = 0.41; p = 0.14).

CONCLUSION

The lack of linear correlation between R2* and magnetic susceptibility measurements of the liver iron concentration with minimal or modest iron overload may be due to the effects of fibrosis and other cellular pathology that interfere with R2* but do not appreciably alter magnetic susceptibility.

Effects of deferasirox dose and decreasing serum ferritin concentrations on kidney function in paediatric patients: an analysis of clinical laboratory data from pooled clinical studies

BACKGROUND

Serious and fatal deferasirox-induced kidney injury has been reported in paediatric patients. This study aimed to investigate the effects of deferasirox dose and serum ferritin concentrations on kidney function and the effect of impaired kidney function on dose-normalised deferasirox minimum plasma concentration (C_min).

METHODS

We did a case-control analysis using pooled data from ten clinical studies. We identified transfusion-dependent patients with thalassaemia, aged 2-15 years, who were receiving deferasirox and had available baseline and follow-up serum creatinine and ferritin measurements. Cases of acute kidney injury (AKI) were defined according to an estimated glomerular filtration rate (eGFR) threshold of 90 mL/min per 1·73 m² or less (if baseline eGFR was ≥100 mL/min per 1·73 m²), an eGFR of 60 mL/min per 1·73 m² or less (if baseline eGFR was <100 mL/min per 1·73 m²), or an eGFR decrease from baseline of at least 25%. Cases were matched to control visits (eGFR ≥120 mL/min per 1·73 m²) on age, sex, study site, and time since drug initiation. We calculated rate ratios for AKI using conditional logistic regression, and evaluated the effect of eGFR changes on C_min.

FINDINGS

Among 1213 deferasirox-treated paediatric patients, 162 cases of AKI and 621 matched control visits were identified. Patients with AKI had a mean 50·2% (SD 15·5) decrease in eGFR from baseline, compared with a 6·9% (29·8) decrease in controls. A significantly increased risk for AKI (rate ratio 1·26, 95% CI 1·08-1·48, p=0·00418) was observed per 5 mg/kg per day increase in deferasirox dispersible tablet dose (equivalent to a 3·5 mg/kg per day dose of film-coated tablets or granules), above the typical starting dose (20 mg/kg per day). An increased risk (1·25, 1·01-1·56, p=0·0400) for AKI was also observed per 250 μg/L decrease in serum ferritin, starting from 1250 μg/L. High-dose deferasirox (dispersible tablet dose >30 mg/kg per day) resulted in an increased risk (4·47, 1·25-15·95, p=0·0209) for AKI when serum ferritin was less than 1000 μg/L. Decreases in eGFR were associated with increased C_min.

INTERPRETATION

Deferasirox can cause AKI in a dose-dependent manner. The increased AKI risk with high-dose deferasirox and lower serum ferritin concentration is consistent with overchelation as a causative factor. Small decreases in eGFR correlate with increased deferasirox C_min, especially in younger patients. Physicians should closely monitor renal function and serum ferritin, use the lowest effective dose to maintain acceptable body iron burden, and interrupt deferasirox treatment when AKI or volume depletion are suspected.

FUNDING

None.

Life-Threatening Drug-Induced Liver Injury in a Patient with β-Thalassemia Major and Severe Iron Overload on Polypharmacy

A 20-year-old male affected by transfusion-dependent β-thalassemia (β-thal), was prescribed intensive chelation therapy with deferoxamine (DFO) and deferiprone (DFP) because of severe hepatic and cardiac iron overload and β-blocker and warfarin to manage a previous event of atrial fibrillation (AFib) and heart failure. After a few months, he developed critical liver failure, renal tubulopathy and severe electrolyte imbalance. Laboratory and instrumental evaluations were performed to carry out differential diagnosis of acute liver failure and an exclusion diagnosis of drug induced liver injury (DILI) was made. The cholestatic pattern suggested warfarin as the main causative agent and polypharmacy, liver iron overload and heart failure as aggravating factors. Warfarin is a drug commonly prescribed in thalassemia patients who often need polypharmacy for the management of anemia- and iron-related complications. Strict monitoring and multidisciplinary approaches are mandatory to avoid preventable mortality in this fragile population.

Significant Hyperbilirubinemia and Acute Hepatocellular Jaundice in a Pediatric Patient Receiving Deferasirox: A Case Report

Despite a boxed warning, postmarketing reports of deferasirox-associated hepatic injury in patients with chronic transfusions are not well described. Hepatic impairment, including failure, has been reported to occur more frequently in patients older than 55 years and in those with significant comorbidities, including liver cirrhosis and multiorgan failure. In this case report, we describe significant hyperbilirubinemia and acute hepatocellular jaundice related to deferasirox in a 7-year-old female being treated for iron overload secondary to chronic transfusions. This report outlines a unique case without preexisting risk factors in which other causes of liver injury are excluded as defined by the Roussel Uclaf Causality Assessment Method, which indicates a probable score of deferasirox causing the injury.