Determination of deferasirox plasma concentrations: do gender, physical and genetic differences affect chelation efficacy?

Crosstalk between ferroptosis and chondrocytes in osteoarthritis: a systematic review of in vivo and in vitro studies

Purpose

Recent scientific reports have revealed a close association between ferroptosis and the occurrence and development of osteoarthritis (OA). Nevertheless, the precise mechanisms by which ferroptosis influences OA and how to hobble OA progression by inhibiting chondrocyte ferroptosis have not yet been fully elucidated. This study aims to conduct a comprehensive systematic review (SR) to address these gaps.

Methods

Following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020, we conducted a comprehensive search of the Embase, Ovid, ProQuest, PubMed, Scopus, the Cochrane Library, and Web of Science databases to identify relevant studies that investigate the association between ferroptosis and chondrocytes in OA. Our search included studies published from the inception of these databases until January 31st, 2023. Only studies that met the predetermined quality criteria were included in this SR.

Results

In this comprehensive SR, a total of 21 studies that met the specified criteria were considered suitable and included in the current updated synthesis. The mechanisms underlying chondrocyte ferroptosis and its association with OA progression involve various biological phenomena, including mitochondrial dysfunction, dysregulated iron metabolism, oxidative stress, and crucial signaling pathways.

Conclusion

Ferroptosis in chondrocytes has opened an entirely new chapter for the investigation of OA, and targeted regulation of it is springing up as an attractive and promising therapeutic tactic for OA.

Systematic review registration

https://inplasy.com/inplasy-2023-3-0044/, identifier INPLASY202330044.

Genetic polymorphisms influencing deferasirox pharmacokinetics, efficacy, and adverse drug reactions: a systematic review and meta-analysis

Objective: Deferasirox is an iron-chelating agent prescribed to patients with iron overload. Due to the interindividual variability of deferasirox responses reported in various populations, this study aims to determine the genetic polymorphisms that influence drug responses. Methods: A systematic search was performed from inception to March 2022 on electronic databases. All studies investigating genetic associations of deferasirox in humans were included, and the outcomes of interest included pharmacokinetics, efficacy, and adverse drug reactions. Fixed- and random-effects model meta-analyses using the ratio of means (ROM) were performed. Results: Seven studies involving 367 participants were included in a meta-analysis. The results showed that subjects carrying the A allele (AG/AA) of ABCC2 rs2273697 had a 1.23-fold increase in deferasirox C_max (ROM = 1.23; 95% confidence interval [CI]:1.06-1.43; p = 0.007) and a lower Vd (ROM = 0.48; 95% CI: 0.36-0.63; p < 0.00001), compared to those with GG. A significant attenuated area under the curve of deferasirox was observed in the subjects with UGT1A3 rs3806596 AG/GG by 1.28-fold (ROM = 0.78; 95% CI: 0.60-0.99; p = 0.04). In addition, two SNPs of CYP24A1 were also associated with the decreased C_trough: rs2248359 CC (ROM = 0.50; 95% CI: 0.29-0.87; p = 0.01) and rs2585428 GG (ROM = 0.47; 95% CI: 0.35-0.63; p < 0.00001). Only rs2248359 CC was associated with decreased C_min (ROM = 0.26; 95% CI: 0.08-0.93; p = 0.04), while rs2585428 GG was associated with a shorter half-life (ROM = 0.44; 95% CI: 0.23-0.83; p = 0.01). Conclusion: This research summarizes the current evidence supporting the influence of variations in genes involved with drug transporters, drug-metabolizing enzymes, and vitamin D metabolism on deferasirox responses.

Iron Chelators in Treatment of Iron Overload

Patients suffering from iron overload can experience serious complications. In such patients, various organs, such as endocrine glands and liver, can be damaged. Although iron is a crucial element for life, iron overload can be potentially toxic for human cells due to its role in generating free radicals. In the past few decades, there has been a major improvement in the survival of patients who suffer from iron overload due to the application of iron chelation therapy in clinical practice. In clinical use, deferoxamine, deferiprone, and deferasirox are the three United States Food and Drug Administration-approved iron chelators. Each of these iron chelators is well known for the treatment of iron overload in various clinical conditions. Based on several up-to-date studies, this study explained iron overload and its clinical symptoms, introduced each of the above-mentioned iron chelators, and evaluated their advantages and disadvantages with an emphasis on combination therapy, which in recent studies seems a promising approach. In numerous clinical conditions, due to the lack of accurate indicators, choosing a standard approach for iron chelation therapy can be difficult; therefore, further studies on the issue are still required. This study aimed to introduce each of these iron chelators, combination therapy, usage doses, specific clinical applications, and their advantages, toxicity, and side effects.

Effect of Aging on Deferasirox Therapy in Transfusion-dependent Patients. A Prospective- Retrospective, Cohort-study

BACKGROUND

Iron-chelation therapy is life-saving in patients on a chronic transfusion regimen as it reduces organ damage related to iron deposition in the tissues. Deferasirox, an iron-chelator, is characterized by pharmacokinetics variability, and some patients may discontinue the treatment due to toxicities.

OBJECTIVE

Understanding whether deferasirox plasma levels are related to patients' specific characteristics could help to optimize DFX dosage.

METHODS

We analyzed deferasirox plasma concentration in 57 transfusion-dependent anemic patients using the HPLC method in this prospective-retrospective cohort study. All outpatients (3 to 98 years) were treated with deferasirox (film-coated tablet) for at least one year (median dose, 16.5 mg/Kg once a day). Deferasirox plasma concentration was normalized for dose/Kg (C/dose) and corrected with a linear regression model that relates C/dose and the time of blood sampling (Cref/dose).

RESULTS

No significant differences in Cref/dose were found between males and females, either between different types of hemoglobinopathies or depending on the presence of the UGT1A1*28 polymorphism. Cref/dose has a positive and significant correlation with age, creatinine, and direct bilirubin. Cref/dose, instead, has a negative and significant correlation with Liver Iron Concentration (LIC), ferritin, and eGFR. Cref/dose was significantly different between three age categories <18yrs, 18-50yrs, and >50yrs, with Cref/dose median values of 1.0, 1.2, and 1.5, respectively.

CONCLUSION

The study evidenced that to ensure the efficacy of deferasirox in terms of control over LIC and, at the same time, a lesser influence on renal function, the dose of the drug to be administered to an elderly patient could be reduced.

Evaluation of Pharmacokinetics and Pharmacodynamics of Deferasirox in Pediatric Patients

Background: Deferasirox (DFX) is commonly used to reduce the chronic iron overload (IO) in pediatric patients. However, the drug is characterized by a large pharmacokinetic variability and approximately 10% of patients may discontinue the treatment due to toxicities. Therefore, the present retrospective study investigated possible correlations between DFX pharmacokinetics and drug-associated toxicities in 39 children (26 males), aged 2–17 years, who underwent an allogeneic hematopoietic stem cell transplantation. Methods: IO was diagnosed by an abdominal magnetic resonance imaging and DFX was started at a median dose of 500 mg/day. DFX plasma concentrations were measured by a high performance liquid chromatographic method with UV detection and they were analysed by nonlinear mixed-effects modeling. Results: The pharmacometric analysis demonstrated that DFX pharmacokinetics were significantly influenced by lean body mass (bioavailability and absorption constant), body weight (volume of distribution), alanine and aspartate transaminases, direct bilirubin, and serum creatinine (clearance). Predicted DFX minimum plasma concentrations (C_trough) accounted for 32.4 ± 23.2 mg/L (mean ± SD), and they were significantly correlated with hepatic/renal and hematological toxicities (p-value < 0.0001, T-test and Fisher’s exact tests) when C_trough threshold values of 7.0 and 11.5 mg/L were chosen, respectively. Conclusions: The population pharmacokinetic model described the interindividual variability and identified C_trough threshold values that were predictive of hepatic/renal and hematological toxicities associated with DFX.

On-demand treatment with the iron chelator deferasirox is ineffective in preventing blood-induced joint damage in haemophilic mice

INTRODUCTION

Early intervention in the devastating process of haemophilic arthropathy (HA) is highly desirable, but no disease-modifying therapy is currently available. Considering the pivotal role of iron in the development of HA, iron chelation is considered a promising therapeutic approach. A previous study in haemophilic mice demonstrated that treatment with the iron chelator deferasirox (DFX) 8 weeks before joint bleed induction, attenuated cartilage damage upon blood exposure. However, in haemophilia patients this approach is not opportune given the unpredictable occurrence of hemarthroses.

AIM

To evaluate the effectiveness of on-demand DFX treatment, initiated immediately after joint bleed induction.

METHODS

A joint bleed was induced in 66 factor VIII-deficient mice by infra-patellar needle puncture. Mice were randomly assigned to treatment with either placebo (drinking water) or DFX (dissolved in drinking water) throughout the study. Five weeks after joint bleed induction, inflammation and cartilage damage were assessed histologically. Joints of ten bleed naive haemophilic mice served as controls.

RESULTS

A joint bleed resulted in significant inflammation and cartilage damage in the blood-exposed joint compared with those of control animals, in both the placebo and DFX group (all p = <.05). No differences in tibiofemoral or patellar inflammation (p = .305 and p = .787, respectively) nor cartilage damage (p = .265 and p = .802, respectively) were found between the blood-exposed joints of both treatment groups.

CONCLUSION

On-demand treatment with DFX does not prevent joint damage following blood exposure in haemophilic mice. DFX seems unable to reach the joint in time to exert its effect before the irreversible harmful process is initiated.

Review of Chromatographic Methods Coupled with Modern Detection Techniques Applied in the Therapeutic Drugs Monitoring (TDM)

Therapeutic drug monitoring (TDM) is a tool used to integrate pharmacokinetic and pharmacodynamics knowledge to optimize and personalize various drug therapies. The optimization of drug dosing may improve treatment outcomes, reduce toxicity, and reduce the risk of developing drug resistance. To adequately implement TDM, accurate and precise analytical procedures are required. In clinical practice, blood is the most commonly used matrix for TDM; however, less invasive samples, such as dried blood spots or non-invasive saliva samples, are increasingly being used. The choice of sample preparation method, type of column packing, mobile phase composition, and detection method is important to ensure accurate drug measurement and to avoid interference from matrix effects and drug metabolites. Most of the reported procedures used liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) techniques due to its high selectivity and sensitivity. High-performance chromatography with ultraviolet detection (HPLC-UV) methods are also used when a simpler and more cost-effective methodology is desired for clinical monitoring. The application of high-performance chromatography with fluorescence detection (HPLC-FLD) with and without derivatization processes and high-performance chromatography with electrochemical detection (HPLC-ED) techniques for the analysis of various drugs in biological samples for TDM have been described less often. Before chromatographic analysis, samples were pretreated by various procedures-most often by protein precipitation, liquid-liquid extraction, and solid-phase extraction, rarely by microextraction by packed sorbent, dispersive liquid-liquid microextraction. The aim of this article is to review the recent literature (2010-2020) regarding the use of liquid chromatography with various detection techniques for TDM.

Main contribution of UGT1A1 and CYP2C9 in the metabolism of UR-1102, a novel agent for the treatment of gout

UR-1102, a novel uricosuric agent for treating gout, has been confirmed to exhibit a pharmacological effect in patients. We clarified its metabolic pathway, estimated the contribution of each metabolic enzyme, and assessed the impact of genetic polymorphisms using human in vitro materials. Glucuronide, sulfate and oxidative metabolites of UR-1102 were detected in human hepatocytes. The intrinsic clearance by glucuronidation or oxidation in human liver microsomes was comparable, but sulfation in the cytosol was much lower, indicating that the rank order of contribution was glucuronidation ≥ oxidation > sulfation. Recombinant UGT1A1 and UGT1A3 showed high glucuronidation of UR-1102. We took advantage of a difference in the inhibitory sensitivity of atazanavir to the UGT isoforms and estimated the fraction metabolised (fm) with UGT1A1 to be 70%. Studies using recombinant CYPs and CYP isoform-specific inhibitors showed that oxidation was mediated exclusively by CYP2C9. The effect of UGT1A1 and CYP2C9 inhibitors on UR-1102 metabolism in hepatocytes did not differ markedly between the wild type and variants.

Recent insight on improving the iron chelation efficacy of deferasirox by adjuvant therapy in transfusion dependent beta thalassemia children with sluggish response

Background: Deferasirox is the first line of treatment in iron overload. In spite of the many studies concerning the efficacy of deferasirox, some patients remain unresponsive to deferasirox.Methods: One hundred and sixty patients were enrolled in stratified-randomized controlled study. Patients were randomly divided into four regimens, group I (n = 40) received 30 mg/kg deferasirox, group II (n = 40) received 20 mg omeprazole and 30 mg/kg deferasirox, group III (n = 40) received 400 mg vitamin E and 30 mg/kg deferasirox and group IV (n = 40) received 420 mg silymarin and 30 mg/kg deferasirox. Blood specimens were collected from each patient for up to 24 h, and then plasma deferasirox concentrations were inspected.Results: Silymarin, Vitamin E, and omeprazole significantly increased the peak plasma concentration of deferasirox (P < 0.001) by 27.9, 14.9 and 2.4 fold, respectively, as compared to deferasirox alone. The bioavailability of deferasirox was improved up to 3.03, 3.57, and 4.98-fold, respectively, following administration of omeprazole, vitamin E, and silymarin compared to deferasirox alone.Conclusion: Silymarin, vitamin E, and omeprazole represent promising adjuvant therapy to improve the chelation efficacy of deferasirox that might also be further applied to enhance the pharmacokinetics of deferasirox to overcome the lack of response.

What is known about deferasirox chelation therapy in pediatric HSCT recipients: two case reports of metabolic acidosis

To date, in pediatric field, various hematological malignancies are increasingly treated with allogeneic hematopoietic stem cell transplantation (allo-HSCT). Iron overload and systemic siderosis often occur in this particular cohort of patients and are associated with poor prognosis. We describe herein the case of two allo-HSCT patients, on treatment with deferasirox; they showed histopathological elements compatible with venoocclusive disease or vanishing bile duct syndrome in ductopenic evolution before deferasirox started. The first patient developed drug-induced liver damage with metabolic acidosis and the second one a liver impairment with Fanconi syndrome. After withdrawing deferasirox treatment, both patients showed improvement. Measurements of drug plasma concentrations were performed by HPLC assay. The reduction and consequent disappearance of symptoms after the suspension of deferasirox substantiate its role in inducing hepatic damage, probably enabling the diagnosis of drug-induced liver damage. But the difficulties in diagnosing drug-related toxicity must be underlined, especially in compromised subjects. For these reasons, in patients requiring iron-chelating therapy, close and careful drug therapeutic monitoring is strongly recommended.

Myelodysplastic syndrome from theoretical review to clinical application view

Myelodysplastic syndromes (MDS), called ineffective hematopoiesis is indicated by bone marrow failure and tendency to acute myeloid leukemia transformation. Since the disease is more common in elderly with non- hematology co-morbidities, the research for less toxic and curative novel agents is essential. More than 12 years without new Food and Drug Administration approved drugs in MDS management through the whole course, only 5 drugs. We summarized the basic data in diagnosis, treatment guidelines and future direction.

Safety and tolerability of deferasirox in pediatric hematopoietic stem cell transplant recipients: one facility's five years' experience of chelation treatment

42 pediatric patients with iron overload, who underwent liver biopsy and DFX treatment after hematopoietic stem cell transplantation were included in the study group. The patients were divided into two groups diversified according to deferasirox trough plasma concentrations (DFX C_trough) with cut-off equal to10 mcg/mL. The average dose of DFX was 25.9 mg/kg in the DFX C_trough < 10 mcg/mL group versus 19.2 mg/kg in the DFX C_trough > 10 mcg/mL group (p=0,0003). The mean duration of DFX treatment was 135.7 days in the DFX C_trough < 10 mcg/mL group versus 41.8 days in the DFX C_trough > 10 mcg/mL group (p<0.0001). The mean tissue iron concentration in the DFX C_trough < 10 mcg/mL group was 261.9 μmol/g versus 133.4 μmol/g in the DFX C_trough > 10 mcg/mL group (p < 0.0001). 21 patients (100%) in the DFX C_trough > 10 mcg/mL group had ductopenia which was complete in 47.6% of them and severe in 52.4%. All patients with particularly high C_trough (> 25 mcg/mL) were found to have total ductopenia. 90.5% of all deferasirox-related adverse events and 100% of major adverse events occurred in the DFX C_trough > 10 mcg/mL group. In the DFX C_trough < 10 mcg/mL group only one patient interrupted chelation therapy versus 16 (84.2%) patients in the DFX C_trough > 10 mcg/mL group. We would recommend a close monitoring in pediatric hematopoietic transplant recipients subjected to deferasirox-based therapy because we have observed a high incidence of adverse events and discontinuation of chelation treatment.

Deferasirox pharmacokinetic and toxicity correlation in β-thalassaemia major treatment

OBJECTIVES

Deferasirox adverse effects include the following: gastrointestinal disturbance, mild elevations in serum creatinine levels and intermittent proteinuria; these events are dose-dependent and reversible with drug discontinuation, but this solution can lead to an inadequate iron chelation. For these reasons, interindividual variability of drug plasma concentration could help the clinical management of deferasirox dosage. We sought to describe deferasirox plasma exposure in a cohort of 60 adult patients.

METHODS

A fully validated chromatographic method was used to quantify deferasirox concentration in plasma collected from β-thalassaemia adult patients. Samples obtained before and after 2, 4, 6 and 24 h drug administration were evaluated. Associations between variables were tested using the Pearson test.

KEY FINDINGS

Concerning pharmacokinetic parameters, a higher interindividual variability was shown. A positive correlation was found between deferasirox area under the concentration curve over 24 h and serum creatinine (r = 0.314; P = 0.018) and between area and drug dose (r = 0.311; P = 0.016). Moreover, a negative correlation resulted among area under the concentration curve over 24 h and serum ferritin (r = -0.291; P = 0.026) and among drug half-life and its dose (r = -0.319; P = 0.013).

CONCLUSIONS

Treatment decision based on the individual characteristics could strongly contribute to minimize toxicity and increase efficacy of deferasirox therapy.

Role of pharmacogenetics on deferasirox AUC and efficacy

AIM

We evaluated deferasirox pharmacokinetic according to SNPs in genes involved in its metabolism and elimination. Moreover, we defined a plasma area under the curve cut-off value predicting therapy response.

PATIENTS & METHODS

Allelic discrimination was performed by real-time PCR. Drug plasma concentrations were measured by a high performance liquid chromatography system coupled with an ultraviolet method.

RESULTS

Pharmacokinetic parameters were significantly influenced by UGT1A1 rs887829C>T, UGT1A3 rs1983023C>T and rs3806596A>G SNPs. Area under the curve cut-off values of 360 μg/ml/h for efficacy were here defined and 250 μg/ml/h for nonresponse was reported. UGT1A3 rs3806596GG and ABCG2 rs13120400CC genotypes were factors able to predict efficacy, whereas UGT1A3 rs3806596GG was a nonresponse predictor.

CONCLUSION

These data show how screening patient's genetic profile may help clinicians to optimize iron chelation therapy with deferasirox.