Updated recommendations on the management of gastrointestinal disturbances during iron chelation therapy with Deferasirox in transfusion dependent patients with myelodysplastic syndrome - Emphasis on optimized dosing schedules and new formulations

Myelodysplastic syndromes: a review of therapeutic progress over the past 10 years

INTRODUCTION

Myelodysplastic syndromes (MDS) represent a range of bone marrow disorders, with patients affected by cytopenias and risk of progression to AML. There are limited therapeutic options available for patients, including hypomethylating agents (azacitidine/decitabine), growth factor support, lenalidomide, and allogeneic stem cell transplant.

AREAS COVERED

This review provides an overview of the progress made over the past decade for emerging therapies for lower- and higher-risk MDS (MDS-HR). We also cover advances in prognostication, supportive care, and use of allogeneic SCT in MDS.

EXPERT OPINION

While there have been no FDA-approved therapies for MDS in the past decade, we anticipate the approval of luspatercept based on results from the MEDALIST trial for patients with lower-risk MDS (MDS-LR) and ringed sideroblasts who have failed or are ineligible for erythropoiesis stimulating agents (ESAs). With growing knowledge of the biologic and molecular mechanisms underlying MDS, it is anticipated that new therapies will be approved in the coming years.

Iron Chelation in Transfusion-Dependent Patients With Low- to Intermediate-1-Risk Myelodysplastic Syndromes: A Randomized Trial

BACKGROUND

Iron chelation therapy (ICT) in patients with lower-risk myelodysplastic syndromes (MDS) has not been evaluated in randomized studies.

OBJECTIVE

To evaluate event-free survival (EFS) and safety of ICT in iron-overloaded patients with low- or intermediate-1-risk MDS.

DESIGN

Multicenter, randomized, double-blind, placebo-controlled trial (TELESTO). (ClinicalTrials.gov: NCT00940602).

SETTING

60 centers in 16 countries.

PARTICIPANTS

225 patients with serum ferritin levels greater than 2247 pmol/L; prior receipt of 15 to 75 packed red blood cell units; and no severe cardiac, liver, or renal abnormalities.

INTERVENTION

Deferasirox dispersible tablets (10 to 40 mg/kg per day) (n = 149) or matching placebo (n = 76).

MEASUREMENTS

The primary end point was EFS, defined as time from date of randomization to first documented nonfatal event (related to cardiac or liver dysfunction and transformation to acute myeloid leukemia) or death, whichever occurred first.

RESULTS

Median time on treatment was 1.6 years (interquartile range [IQR], 0.5 to 3.1 years) in the deferasirox group and 1.0 year (IQR, 0.6 to 2.0 years) in the placebo group. Median EFS was prolonged by approximately 1 year with deferasirox versus placebo (3.9 years [95% CI, 3.2 to 4.3 years] vs. 3.0 years [CI, 2.2 to 3.7 years], respectively; hazard ratio, 0.64 [CI, 0.42 to 0.96]). Adverse events occurred in 97.3% of deferasirox recipients and 90.8% of placebo recipients. Exposure-adjusted incidence rates of adverse events (≥15 events per 100 patient treatment-years) in deferasirox versus placebo recipients, respectively, were 24.7 versus 23.9 for diarrhea, 21.8 versus 18.7 for pyrexia, 16.7 versus 22.7 for upper respiratory tract infection, and 15.9 versus 0.9 for increased serum creatinine concentration.

LIMITATIONS

The protocol was amended from a phase 3 to a phase 2 study, with a reduced target sample size from 630 to 210 participants. There was differential follow-up between treatment groups.

CONCLUSION

The findings support ICT in iron-overloaded patients with low- to intermediate-1-risk MDS, with longer EFS compared with placebo and a clinically manageable safety profile. Therefore, ICT may be considered in these patients.

PRIMARY FUNDING SOURCE

Novartis Pharma AG.

Systematic review and meta-analysis of the effect of iron chelation therapy on overall survival and disease progression in patients with lower-risk myelodysplastic syndromes

The impact of iron chelation therapy (ICT) on overall survival (OS) and progression to acute myeloid leukemia (AML) in patients with iron overload and International Prognostic Scoring System low- or intermediate-risk myelodysplastic syndromes (MDS) is not well understood. We conducted a systematic review and meta-analysis of published studies of ICT in patients with MDS to better elucidate these relationships. We searched PubMed, EMBASE, Cochrane databases, and the World Health Organization Clinical Trial Registry for studies reporting the impact of ICT on OS in patients with low- or intermediate-risk MDS. Studies were examined for demographics, effect measures, and potential bias risk. Fixed and random-effects models were used to calculate adjusted OS and adjusted hazards ratio (aHR) estimates, respectively, among the different studies. Nine observational studies (four prospective and five retrospective) were identified. For patients with MDS, ICT was associated with an overall lower risk of mortality compared with no ICT (aHR 0.42; 95% confidence interval (CI) 0.28-0.62; P < 0.01); however, there was significant heterogeneity across the studies. In studies reporting progression to AML, ICT was not associated with decreased risk of progression (odds ratio 0.68; 95% CI 0.31-1.43; P < 0.030). This systematic review and meta-analysis of nine nonrandomized trials demonstrated significant reduction in risk of mortality in patients with iron overload and low- or intermediate-risk MDS treated with ICT; however, a causal relationship cannot be established. Randomized, controlled trials are needed to more definitively evaluate the relationship between ICT and survival in patients with iron overload and low- or intermediate-risk MDS.

Optimising management of deferasirox therapy for patients with transfusion-dependent thalassaemia and lower-risk myelodysplastic syndromes

Effective iron chelation therapy is an important part of treatment in patients with transfusion-dependent thalassaemia and lower-risk myelodysplastic syndromes (MDS). Key strategies for optimising iron chelation therapy include ensuring good adherence and preventing and managing adverse events (AEs). Good adherence to iron chelation therapy with deferoxamine and deferasirox has been linked to improved survival and/or reductions in complications related to iron overload; however, maintaining good adherence to iron chelators can be challenging. Patients with transfusion-dependent thalassaemia or lower-risk MDS showed better adherence to the deferasirox film-coated tablet (FCT) formulation than to the deferasirox dispersible tablet formulation in the ECLIPSE trial, reflecting in part the improved palatability and convenience of deferasirox FCT. As well as affecting adherence, AEs may lead to dose reduction, interruption or discontinuation, resulting in suboptimal iron chelation therapy. Preventing and successfully managing AEs may help limit their impact on adherence, and following dosage and administration recommendations for iron chelators such as deferasirox may help minimise AEs and optimise treatment in patients with transfusion-dependent thalassaemia and lower-risk MDS.

Clinical consequences of iron overload in patients with myelodysplastic syndromes: the case for iron chelation therapy

INTRODUCTION

Patients with myelodysplastic syndromes (MDS) are at increased risk of iron overload due to ineffective erythropoiesis and chronic transfusion therapy. The clinical consequences of iron overload include cardiac and/or hepatic failure, endocrinopathies, and infection risk. Areas covered: Iron chelation therapy (ICT) can help remove excess iron and ultimately reduce the clinical consequences of iron overload. The authors reviewed recent (last five years) English-language articles from PubMed on the topic of iron overload-related complications and the use of ICT (primarily deferasirox) to improve outcomes in patients with MDS. Expert commentary: While a benefit of ICT has been more firmly established in other transfusion-dependent conditions, such as thalassemia, its role in reducing iron overload in MDS remains controversial due to the lack of prospective controlled data demonstrating a survival benefit. Orally administered chelation agents (e.g. deferasirox) are now available, and observational and/or retrospective data support a survival benefit of using ICT in MDS. The placebo-controlled TELESTO trial (NCT00940602) is currently examining the use of deferasirox in MDS patients with iron overload, and is evaluating specifically whether use of ICT to alleviate iron overload can also reduce iron overload-related complications in MDS and improve survival.

Transitioning Patients With Iron Overload From Exjade to Jadenu

Iron overload is a concern for patients who require chronic transfusions as a result of inherited or acquired anemias, including sickle cell disease, thalassemia, and myelodysplastic syndromes. Iron chelation therapy (ICT) is the primary treatment for iron overload in these patients. The ICT deferasirox, which has been available as an oral dispersible tablet for liquid suspension, is now also available as a once-daily, film-coated tablet (FCT). Deferasirox FCT allows greater convenience and may be associated with fewer gastrointestinal side effects versus the original formulation. Dose adjustment increments, determined by titration monitoring, are lower for the FCT because of greater bioavailability.

Iron overload in myelodysplastic syndromes (MDS)

Iron overload (IOL) starts to develop in MDS patients before they become transfusion-dependent because ineffective erythropoiesis suppresses hepcidin production in the liver and thus leads to unrestrained intestinal iron uptake. However, the most important cause of iron overload in MDS is chronic transfusion therapy. While transfusion dependency by itself is a negative prognostic factor reflecting poor bone marrow function, the ensuing transfusional iron overload has an additional dose-dependent negative impact on the survival of patients with lower risk MDS. Cardiac dysfunction appears to be important in this context, as a consequence of chronic anemia, age-related cardiac comorbidity, and iron overload. Another potential problem is iron-related endothelial dysfunction. There is some evidence that with increasing age, high circulating iron levels worsen the atherosclerotic phenotype. Transfusional IOL also appears to aggravate bone marrow failure in MDS, through unfavorable effects on mesenchymal stromal cells as well a hematopoietic cells, particularly erythroid precursors. Patient series and clinical trials have shown that the iron chelators deferoxamine and deferasirox can improve hematopoiesis in a minority of transfusion-dependent patients. Analyses of registry data suggest that iron chelation provides a survival benefit for patients with MDS, but data from a prospective randomized clinical trial are still lacking.

Overcoming barriers to treating iron overload in patients with lower-risk myelodysplastic syndrome

Myelodysplastic syndromes (MDS) constitute a group of heterogeneous hematopoietic neoplasms characterized by ineffective erythropoiesis, anemia, and/or cytopenias. Supportive care for patients with MDS involves frequent red blood cell transfusions, which places patients with ongoing transfusional dependence (TD) at risk for iron overload (IO). Development of IO and tissue iron deposition can increase the risk of cardiac, hepatic, and endocrine toxicities, infection, and progression to acute myeloid leukemia. Iron chelation therapy (ICT) is an option for lower-risk MDS patients to reduce their degree of IO and possibly improve survival; use of these agents in thalassemia patients with TD and IO has been associated with reduced IO-associated complications and better survival. At present, there are several barriers to the regular use of ICT, such as a lack of randomized trial evidence and consistent guidance on diagnosis of IO and when to implement ICT, as well as barriers in adherence to/tolerability of ICT.

Advances in iron chelation therapy: transitioning to a new oral formulation

Iron overload is a concern for patients who require repeated red-blood-cell transfusions due to conditions such as sickle cell disease, thalassemia, or myelodysplastic syndromes. The recommended treatment for removing excess iron in these patients is iron chelation therapy. Currently available iron chelators include deferoxamine, which is administered by injection, and deferasirox and deferiprone, both of which are administered orally. Adherence to iron chelator therapy is an important consideration and may be affected by side effects. A new formulation of deferasirox, a film-coated tablet (FCT), has the potential to improve adherence by offering greater flexibility in administration compared with the original formulation of deferasirox, a dispersible tablet (DT) for oral suspension. This review provides an overview of the currently available iron chelator formulations, with a focus on a comparison between deferasirox DT for oral suspension and deferasirox FCT. The new formulation may be associated with fewer side effects and has increased bioavailability. In addition, alternative strategies for iron chelation, such as combining two different iron chelators, will be discussed.

Evaluation of a new tablet formulation of deferasirox to reduce chronic iron overload after long-term blood transfusions

Transfusion-dependent anemia is a common feature in a wide array of hematological disorders, including thalassemia, sickle cell disease, aplastic anemia, myelofibrosis, and myelo-dysplastic syndromes. In the absence of a physiological mechanism to excrete excess iron, chronic transfusions ultimately cause iron overload. Without correction, iron overload can lead to end-organ damage, resulting in cardiac, hepatic, and endocrine dysfunction/failure. Iron chelating agents are utilized to reduce iron overload, as they form a complex with iron, leading to its clearance. Iron chelation has been proven to decrease organ dysfunction and improve survival in certain transfusion-dependent anemias, such as β-thalassemia. Several chelating agents have been approved by the United States Food and Drug Administration for the treatment of iron overload, including deferoxamine, deferiprone, and deferasirox. A variety of factors have to be considered when choosing an iron chelator, including dosing schedule, route of administration, tolerability, and side effect profile. Deferasirox is an orally administered iron chelator with proven efficacy and safety in multiple hematological disorders. There are two formulations of deferasirox, a tablet for suspension, and a new tablet form. This paper is intended to provide an overview of iron overload, with a focus on deferasirox, and its recently approved formulation Jadenu^® for the reduction of transfusional iron overload in hematological disorders.