Iron overload in myelodysplastic syndromes: A Canadian consensus guideline

Blood donation and heavy metal poisoning in developing nations: Any link?

Long term health effects of heavy metal exposure from both occupational and environmental settings involve multi-organ toxicities including but not limited to disturbances of neurological, cognitive, and metabolic processes, immune system dysregulation, carcinogenesis and sometimes permanent disabilities. Humans are exposed to toxic metals through various sources and routes of entry. The risk of heavy metal poisoning from donor blood has been the subject of many scientific investigations. In this review we highlight how the access to a safe and adequate blood transfusion with minimal risk of toxic metals to recipients is a public health challenge, especially in developing nations. For quality assurance purposes, blood donors are screened for various blood-borne pathogens, but screening for toxic metal levels is not routine. Evidence from scientific studies used in this review lends credence to the risk of heavy metal poisoning from donors with high blood concentrations of these heavy metals. The risk of toxicity is exceptionally high in vulnerable populations such as neonates and preterm infants, as well as in pregnant women and other individuals with conditions requiring multiple blood transfusions. This is worse in developing countries where some members of the population engage in illegal refining and artisanal mining activities. In order to reduce toxic metal exposure in vulnerable populations, blood meant for transfusion in vulnerable subjects, e.g. children, should be routinely screened for heavy metal concentrations. Patients receiving multiple blood transfusions should also be monitored for iron overload and its attendant toxicities.

Low risk of iron overload or anaphylaxis during treatment of restless legs syndrome with intravenous iron: a consecutive case series in a regular clinical setting

OBJECTIVE

To evaluate the incidence of iron overload and anaphylaxis following intravenous (IV) iron treatment of restless legs syndrome (RLS).

METHODS

A total of 58 consecutive RLS patients, meeting clinical requirements for IV iron treatment according to current IRLSSG guidelines were recruited. IV iron treatment consisted of two 500 mg infusions of ferric carboxymaltose (FCM) administered five days apart. During each of the three follow-up visits we obtained blood samples, substantia nigra echogenity index (SNEI) by means of transcranial sonography (TCS), and assessed the severity of RLS symptoms (IRLS scale). "Iron overload risk" was defined as transferrin saturation (TSAT) > 45% on two consecutive follow-up visits. In patients who had a reduction in systemic iron levels following treatment, an additional 500 mg of FCM was administered when feasible. In such cases an additional two follow-up visits were performed.

RESULTS

Among the total sample, only 2/58 participants met criteria for iron overload risk. They had no evidence of liver damage and did not require additional treatment. Among the 21 patients receiving an additional 500 mg infusion after, only one patient was diagnosed with iron overload risk. Among these three patients, only one was a hemochromatosis gene carrier. No anaphylaxis or other side-effects were reported.

CONCLUSIONS

In real-life clinical conditions, the risk of iron overload is low when IV FCM is administered according to the safety limits defined in the current RLS treatment guidelines. However, a close clinical follow-up with periodic blood sampling for iron status, is needed.

Lifetime Transfusion Burden and Transfusion-Related Iron Overload in Adult Survivors of Solid Malignancies

BACKGROUND

Limited data exist on transfusion burden and transfusion-related iron overload in adult survivors of solid malignancies.

METHODS

Hospital-specific cancer registry data of patients with solid tumor receiving systemic anticancer treatment between January 2008 and September 2009 at the Oncology Department of the Leiden University Medical Center (The Netherlands) were retrieved and cross-referenced with red blood cell (RBC) transfusion records. Individual lifetime transfusion burden was captured in April 2015. Multitransfused long-term survivors with serum ferritin >500 μg/L were subsequently screened for hepatic and cardiac iron overload using 1.5 Tesla magnetic resonance imaging.

RESULTS

The study population consisted of 775 adult patients with solid cancer (45.2% male; median age, 58 years; >75% chemotherapy-treated), 423 (54.6%) of whom were transfused with a median of 6.0 RBC units (range 1-67). Transfusion triggers were symptomatic anemia or hemoglobin <8.1-8.9 g/dL prior to each myelosuppressive chemotherapy cycle. We identified 123 (15.9%) patients across all tumor types with a lifetime transfusion burden of ≥10 RBC units. In the absence of a hemovigilance program, none of these multitransfused patients was screened for iron overload despite a median survival of 4.6 years. In 2015 at disclosure of transfusion burden, 26 multitransfused patients were alive. Six (23.1%) had hepatic iron overload: 3.9-11.2 mg Fe/g dry weight. No cardiac iron depositions were found.

CONCLUSION

Patients with solid malignancies are at risk for multitransfusion and iron overload even when adhering to restrictive RBC transfusion policies. With improved long-term cancer survivorship, increased awareness of iatrogenic side effects of supportive therapy and development of evidence-based guidelines are essential.

IMPLICATIONS FOR PRACTICE

In the presence of a restrictive transfusion policy, ∼30% of transfused adult patients with solid cancer are multitransfused and ∼50% become long-term survivors, underscoring the need for evidence-based guidelines for the detection and management of transfusion-related iron overload in this group of patients. In each institution, a hemovigilance program should be implemented that captures the lifetime cumulative transfusion burden in all patients with cancer, irrespective of tumor type. This instrument will allow timely assessment and treatment of iron overload in cancer survivors, thus preventing organ dysfunction and decreased quality of life.

Scaffold Based Search on the Desferithiocin Archetype

Iron overload disorder and diseases where iron mismanagement plays a crucial role require orally available iron chelators with favourable pharmacokinetic and toxicity profile. Desferrithiocin (DFT), a tridentate and orally available iron chelator has a favourable pharmacokinetic profile but its use has been clinically restricted due to its nephrotoxic potential. The chemical architecture of the DFT has been naturally well optimized for better iron chelation and iron clearance from human biological system. Equally they are also responsible for its toxicity. Hence, subsequent research has been devoted to develop a non-nephrotoxic analogue of DFT without losing its iron clearance ability. The review has been designed to classify the compounds reported till date and to discuss the structure activity relationship with reference to modifications attempted at different positions over pyridine and thiazoline ring of DFT. Compounds are clustered under two major classes: (i) Pyridine analogues and (ii) phenyl analogue and further each class has been further subdivided based on the presence or absence and the number of hydroxy functional groups present over pyridine or phenyl ring of the DFT analogues. Finally a summary and few insights into the development of newer analogues are provided.

Iron overload in myelodysplastic syndromes: Evidence based guidelines from the Canadian consortium on MDS

In 2008 the first evidence-based Canadian consensus guideline addressing the diagnosis, monitoring and management of transfusional iron overload in patients with myelodysplastic syndromes (MDS) was published. The Canadian Consortium on MDS, comprised of hematologists from across Canada with a clinical and academic interest in MDS, reconvened to update these guidelines. A literature search was updated in 2017; topics reviewed include mechanisms of iron overload induced cellular damage, evidence for clinical endpoints impacted by iron overload including organ dysfunction, infections, marrow failure, overall survival, acute myeloid leukemia progression, and endpoints around hematopoietic stem-cell transplant. Evidence for an impact of iron reduction on the same endpoints is discussed, guidelines are updated, and areas identified where evidence is suboptimal. The guidelines address common questions around the diagnosis, workup and management of iron overload in clinical practice, and take the approach of who, when, why and how to treat iron overload in MDS. Practical recommendations for treatment and monitoring are made. Evidence levels and grading of recommendations are provided for all clinical endpoints examined.

To chelate or not to chelate in MDS: That is the question!

Myelodysplastic syndromes (MDS) are a heterogeneous group of hemopathies that exhibit physical manifestations with clinical consequences of bone marrow failure and inherent risk of progression to acute myeloid leukemia. Iron overload (IO) is common in MDS due to chronic transfusion support and disease-related alterations in iron metabolism. IO has been conclusively associated with inferior outcomes among MDS patients. Despite lack of randomized trials showing a survival impact of iron chelation therapy (ICT), ICT is recommended by experts and guidelines for select MDS patients with IO and is often used. The availability of effective oral ICT agents has reignited the controversy regarding ICT use in patients with MDS and IO. Here we summarize the studies evaluating the value of ICT in MDS and suggest a practical approach for use of these therapies. We also highlight controversies regarding use of ICT in MDS and discuss some ongoing efforts to answer these questions.

Iron chelation therapy in lower IPSS risk myelodysplastic syndromes; which subtypes benefit?

BACKGROUND

Analyses suggest MDS patients with higher serum ferritin levels (SF) have inferior overall survival (OS), in one study across MDS subtypes. Multiple analyses suggest those with high SF receiving iron chelation therapy (ICT) have superior OS, but which MDS subtypes benefit from ICT remains undefined.

METHODS

We performed survival analyses of MDS subtypes by receipt of ICT.

RESULTS

182 MDS were lower IPSS risk and received red blood cell (RBC) transfusions; 63 received ICT. For the entire cohort, receiving ICT independently predicted superior OS in a multivariate analysis (hazard ratio for death 0.3, p=0.01). Features differing for ICT and non-ICT patients, respectively, were: age; IPSS risk group; number of RBC units transfused; and SF, p≤0.03 for all. At a median follow up of 76.5 and 28.4 months, 65.1% and 63.0% were alive. Median OS (months) for ICT and non-ICT patients was: RA, 140.9 and 36.3, p=0.0008; RARS/RARS-t, 133.4 and 73.3, p=0.02. For RCMD/RCMD-RS, p=NS, however, 3 (20%) had significant erythroid improvement with ICT; other subtypes had small numbers.

DISCUSSION

In this retrospective analysis, RA and RARS/RARS-t patients receiving ICT had superior OS to non-ICT patients. These findings should be verified and other MDS subtypes examined in larger prospective analyses.

Overall survival in lower IPSS risk MDS by receipt of iron chelation therapy, adjusting for patient-related factors and measuring from time of first red blood cell transfusion dependence: an MDS-CAN analysis

Analyses suggest iron overload in red blood cell (RBC) transfusion-dependent (TD) patients with myleodysplastic syndrome (MDS) portends inferior overall survival (OS) that is attenuated by iron chelation therapy (ICT) but may be biassed by unbalanced patient-related factors. The Canadian MDS Registry prospectively measures frailty, comorbidity and disability. We analysed OS by receipt of ICT, adjusting for these patient-related factors. TD International Prognostic Scoring System (IPSS) low and intermediate-1 risk MDS, at RBC TD, were included. Predictive factors for OS were determined. A matched pair analysis considering age, revised IPSS, TD severity, time from MDS diagnosis to TD, and receipt of disease-modifying agents was conducted. Of 239 patients, 83 received ICT; frailty, comorbidity and disability did not differ from non-ICT patients. Median OS from TD was superior in ICT patients (5·2 vs. 2·1 years; P < 0·0001). By multivariate analysis, not receiving ICT independently predicted inferior OS, (hazard ratio for death 2·0, P = 0·03). In matched pair analysis, OS remained superior for ICT patients (P = 0·02). In this prospective, non-randomized analysis, receiving ICT was associated with superior OS in lower IPSS risk MDS, adjusting for age, frailty, comorbidity, disability, revised IPSS, TD severity, time to TD and receiving disease-modifying agents. This provides additional evidence that ICT may confer clinical benefit.

Role of serum ferritin level on overall survival in patients with myelodysplastic syndromes: Results of a meta-analysis of observational studies

BACKGROUND

The role of serum ferritin (SF) as a prognostic factor has been analyzed in patients with myelodysplastic syndromes (MDS) who have undergone hematopoietic stem cell transplantation (HSCT), but the prognostic role of elevated SF levels is still controversial in lower risk MDS patients. Therefore, we performed a meta-analysis of all available published literature to evaluate whether elevated SF levels are associated with a worse overall survival (OS) among patients with low risk MDS.

MATERIAL AND METHODS

A systematic bibliographic search of relevant studies was undertaken in accordance with guidelines for meta-analysis of observational studies in epidemiology. Electronic databases were searched through July 2016 for studies examining the level of SF as a prognostic factor in the adults affected by MDS.

RESULTS

Six articles were included in the meta-analysis. A significant association between OS and SF was achieved for the threshold of SF≥1000 ng/mL, when the only study that used SF cut-off ≥2000 ng/mL was not included in the meta-analysis (RR = 1.33; 95% CI = 1.06-1.67). The estimated risk was 2.58 (95% CI = 1.41-4.74) when a SF cut-off≥500 ng/mL was considered.

CONCLUSIONS

Our findings underlined a worse survival in patients with MDS who had higher SF levels. The association was stronger and achieved statistical significance after stratification of analyses in which we excluded cut-offs of SF level considered as outliers. These results suggest that negative impact on OS already exist at SF level ≥500 ng/mL. Prospective studies, are needed to better understand this relationship and, above all, to clarify whether earlier iron chelation therapy could improve patients' OS.

Toxicity of iron overload and iron overload reduction in the setting of hematopoietic stem cell transplantation for hematologic malignancies

Iron is an essential element for key cellular metabolic processes. However, transfusional iron overload (IOL) may result in significant cellular toxicity. IOL occurs in transfusion dependent hematologic malignancies (HM), may lead to pathological clinical outcomes, and IOL reduction may improve outcomes. In hematopoietic stem cell transplantation (SCT) for HM, IOL may have clinical importance; endpoints examined regarding an impact of IOL and IOL reduction include transplant-related mortality, organ function, infection, relapse risk, and survival. Here we review the clinical consequences of IOL and effects of IOL reduction before, during and following SCT for HM. IOL pathophysiology is discussed as well as available tests for IOL quantification including transfusion history, serum ferritin level, transferrin saturation, hepcidin, labile plasma iron and other parameters of iron-catalyzed oxygen free radicals, and organ IOL by imaging. Data-based recommendations for IOL measurement, monitoring and reduction before, during and following SCT for HM are made.

Screening for hemosiderosis in patients receiving multiple red blood cell transfusions

BACKGROUND

The dramatic impact of hemosiderosis on survival in chronically transfused patients with hereditary anemia is well known. We evaluated whether patients receiving multiple red blood cell (RBC) transfusions are adequately screened for hemosiderosis.

METHODS

We retrospectively assessed hemosiderosis screening and prevalence in adult patients that received over twenty RBC units in the University Medical Centre Utrecht from 2010 till 2015. Hemosiderosis was defined as ferritin ≥1000 μg/L. Adequate screening for chronically transfused patients was defined as any ferritin determined up to 3 months before or any moment after the last transfusion, while for patients that received all transfusions within 3 months (bulk transfusion), ferritin had to be determined after at least twenty transfusions.

RESULTS

Of 471 patients, only 38.6% was adequately screened and hemosiderosis prevalence was 46.7%. Hemosiderosis prevalence was 47% in the chronic transfusion group and 12% in the bulk transfusion group. In patients transfused because of hematological malignancy or cardiothoracic surgery, respectively, 74% and 31% were adequately screened and hemosiderosis prevalence was 53% and 13%, respectively.

CONCLUSION

Hemosiderosis screening in our routine practice is suboptimal. Hemosiderosis is not an exclusive complication of multiple transfusions in the hematology ward. We recommend screening for hemosiderosis in all patients receiving multiple transfusions.

Management of iron overload in the Canadian hematology/oncology population: Implications for nursing practice

Red blood cell (RBC) transfusions are vital for many patients with chronic anemias associated with oncologic/hematologic disorders. However, repeated transfusions over time can lead to iron overload, which, if left untreated, can increase the risk of further malignancy and end-organ damage. Nurses and other health care professionals may not be aware of the significant implications of RBC transfusions and iron overload in patients with hematological/oncological disorders. This article was developed by a group of Canadian nurse practitioners and specialized oncology nurses to help improve health care professionals' understanding of iron overload in oncology patients and its associated risks, as well as provide a practical guide for the management of patients receiving treatment for this potentially serious condition.

New insights into transfusion-related iron toxicity: Implications for the oncologist

Iron overload is a potentially life-threatening consequence of multiple red-blood-cell transfusions. Here, we review factors affecting excess iron distribution and its damage to specific tissues, as well as mechanisms of oncogenesis by iron. Although consequences of transfusional iron overload are best described in thalassemia major and related inherited anemias, they are increasingly recognized in acquired conditions, such as myelodysplastic syndromes (MDS). Iron overload in MDS not only impacts on certain tissues, but may affect the clonal evolution of MDS through generation of reactive oxygen species. Iron overload may also influence hematopoietic-stem-cell-transplantation outcomes. Novel MRI methods for assessing body iron have impacted significantly on outcome in inherited anemias by allowing monitoring of iron burden and iron chelation therapy. This approach is increasingly being used in MDS and stem-cell-transplant procedures. Knowledge gained from managing transfusional iron overload in inherited anemias may be translated to general oncology, with potential for improved patient outcomes.

A case of transfusion independence in a patient with myelodysplastic syndrome using deferasirox, sustained for two years after stopping therapy

Patients with myelodysplastic syndrome (mds) experience clinical complications related to progressive marrow failure and have an increased risk of developing acute myeloid leukemia. Frequent red blood cell transfusion can lead to clinical iron overload and is associated with decreased survival in mds patients. Iron chelation therapy reduces markers of iron overload and prevents end-organ damage. Here, we present the case of a patient with low-risk mds with transfusional iron overload. He was treated for 2 years with an oral iron chelator, deferasirox, and after 12 months of treatment, he experienced a hemoglobin increase of more than 50 g/L, becoming transfusion-independent. He has remained transfusion-independent, with a normal hemoglobin level, for more than 2 years since stopping chelation therapy. Hematologic and erythroid responses have previously been reported in mds patients treated with iron chelation. The durability of our patient's response suggests that iron chelation might alter the natural history of mds in some patients.

Deferasirox in a refractory anemia after other treatment options: case report and literature review

Deferasirox, represents an effective iron chelator drug in lower risk myelodysplastic syndromes. Reduction in oxidative stress is responsible of the hematologic improvement but further explanation may impact on its benefit. Biological and clinical studies are necessary to better define mechanisms of action, assess toxicities, and predicting factors of response.

Toward resolving the unsettled role of iron chelation therapy in myelodysplastic syndromes

Transfusion dependent low risk myelodysplastic syndromes (MDS) patients, eventually develop iron overload. Iron toxicity, via oxidative stress, can damage cellular components and impact organ function. In thalassemia major patients, iron chelation therapy lowered iron levels with recovery of cardiac and liver functions and significant improvement in survival. Several noncontrolled studies show inferior survival in MDS patients with iron overload, including an increase in transplant-related mortality and infection risk while iron chelation appears to improve survival in both lower risk MDS patients and in stem cell transplant settings. Collated data are presented on the pathophysiological impact of iron overload; measuring techniques and chelating agents' therapy positive impact on hematological status and overall survival are discussed. Although suggested by retrospective analyses, the lack of clear prospective data of the beneficial effects of iron chelation on morbidity and survival, the role of iron chelation therapy in MDS patients remains controversial.

Clinical outcomes of transfusion-associated iron overload in patients with refractory chronic anemia

BACKGROUND

The purpose of this study was to evaluate the clinical outcomes of transfusion-associated iron overload in patients with chronic refractory anemia.

METHODS

Clinical manifestations, main organ function, results of computed tomography (CT), endocrine evaluation, and serum ferritin levels were analyzed retrospectively in 13 patients who were transfusion-dependent for more than 1 year (receiving >50 units of red blood cells) to determine the degree of iron overload and efficacy of iron-chelating therapy.

RESULTS

Serum ferritin levels increased to 1,830-5,740 ng/mL in all patients. Ten patients had abnormal liver function. The CT Hounsfield units in the liver increased significantly in eleven patients, and were proportional to their serum ferritin levels. Skin pigmentation, liver dysfunction, and endocrine dysfunction were observed in nine patients with serum ferritin >3,500 ng/mL, eight of whom have since died. Interestingly, serum ferritin levels did not decrease significantly in nine transfusion-dependent patients who had received 15-60 days of iron-chelating therapy.

CONCLUSION

Transfusion-dependent patients may progress to secondary iron overload with organ impairment, which may be fatal in those who are heavily iron-overloaded. The CT Hounsfield unit is a sensitive indicator of iron overload in the liver. Iron chelation therapy should be initiated when serum ferritin is >1,000 ng/mL and continued until it is <1,000 ng/mL in transfusional iron-overloaded patients.

Review of therapeutic options and the management of patients with myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a poorly understood group of disorders caused by one or more genetic aberrations in the bone marrow-derived cell line responsible for hematopoiesis. Recent advances in genetic medicine have offered new insights into the epigenesis as well as the prognosis of MDS, but have not resulted in new or improved curative treatment options. Bone marrow transplantation, introduced before the advent of genetic medicine, is still the only potential cure. Advances in other medical and pharmaceutical areas have broadened the scope of supportive care and disease-modifying therapies, and treating physicians now have a broad range of disease management options depending on a patient's likely prognosis. There is now clear evidence that appropriate supportive care and therapeutic intervention can improve progression-free and overall survival of MDS patients.

Iron chelation therapy in myelodysplastic syndromes: where do we stand?

Anemia leading to transfusion dependency (TD) and iron overload (IO) is commonly observed in patients with myelodysplastic syndromes (MDS). In MDS, TD and IO have been retrospectively associated with inferior survival and worse clinical outcomes, including cardiac, hepatic and endocrine dysfunction, and, in some analyses, with leukemic progression and infectious complications. Although suggested by retrospective analyses, clear prospective documentation of the beneficial effects of iron chelation therapy (ICT) on organ function and survival in MDS patients with TD and IO is currently lacking. Consequently, the role of ICT in MDS patients with TD and IO remains a very controversial aspect in the management of MDS. In this review, the authors summarize the current knowledge regarding IO in MDS and the role of ICT.

Hematologic responses to deferasirox therapy in transfusion-dependent patients with myelodysplastic syndromes

BACKGROUND

Reductions in transfusion requirements/improvements in hematologic parameters have been associated with iron chelation therapy in transfusion-dependent patients, including those with myelodysplastic syndromes; data on there reductions/improvements have been limited to case reports and small studies.

DESIGN AND METHODS

To explore this observation in a large population of patients, we report a post-hoc analysis evaluating hematologic response to deferasirox in a cohort of iron-overloaded patients with myelodysplastic syndromes enrolled in the Evaluation of Patients' Iron Chelation with Exjade(®) (EPIC) study using International Working Group 2006 criteria.

RESULTS

Two-hundred and forty-seven, 100 and 50 patients without concomitant medication for myelodysplastic syndromes were eligible for analysis of erythroid, platelet and neutrophil responses, respectively. Erythroid, platelet and neutrophil responses were observed in 21.5% (53/247), 13.0% (13/100) and 22.0% (11/50) of the patients after a median of 109, 169 and 226 days, respectively. Median serum ferritin reductions were greater in hematologic responders compared with non-responders at end of study, although these differences were not statistically significant. A reduction in labile plasma iron to less than 0.4 μmol/L was observed from week 12 onwards; this change did not differ between hematologic responders and non-responders.

CONCLUSIONS

This analysis suggests that deferasirox treatment for up to 1 year could lead to improvement in hematologic parameters in some patients with myelodysplastic syndromes.

Optimizing therapy for iron overload in the myelodysplastic syndromes: recent developments

The myelodysplastic syndromes (MDS) are characterized by cytopenias and risk of progression to acute myeloid leukaemia (AML). Most MDS patients eventually require transfusion of red blood cells for anaemia, placing them at risk of transfusional iron overload. In β-thalassaemia major, transfusional iron overload leads to organ dysfunction and death; however, with iron chelation therapy, organ function is improved, and survival improved to near normal and correlated with the degree of compliance with chelation. In lower-risk MDS, several nonrandomized studies suggest an adverse effect of iron overload on survival and that lowering iron with chelation may minimize this impact. Emerging data indicate that chelation may improve organ function, particularly hepatic function, and a minority of patients may have improvement in cell counts and decreased transfusion requirements. While guidelines for MDS generally recommend chelation in selected lower-risk patients, data from nonrandomized trials suggest iron overload may impact adversely on the outcome of higher-risk MDS and stem cell transplantation (SCT). This effect may be due to increased transplant-related mortality, infection and AML progression, and preliminary data suggest that lowering iron may be beneficial in this patient group. Other areas of active and future investigation include optimizing the monitoring of iron overload using imaging such as T2* MRI and measures of labile iron and oxidative stress; correlating new methods of measuring iron to clinical outcomes; clarifying the contribution of different cellular and extracellular iron pools to iron toxicity; optimizing chelation by using agents that access the appropriate iron pools to minimize the relevant clinical consequences in individual patients; and incorporating measures of quality of life and co-morbidities into clinical trials of chelation in MDS. It should be noted that chelation is costly and potentially toxic, and in MDS should be initiated after weighing potential risks and benefits for each patient until more definitive data are available. In this review, data on the impact of iron overload in MDS and SCT are discussed; for example, several noncontrolled studies show inferior survival in patients with iron overload in these clinical settings, including an increase in transplant-related mortality and infection risk. Possible mechanisms of iron toxicity include oxidative stress, which can damage cellular components, and the documented impact of lowering iron on organ function with measures such as iron chelation therapy includes an improvement in elevated liver transaminases. Lowering iron also appears to improve survival in both lower-risk MDS and SCT in nonrandomized studies. Selected aspects of iron metabolism, transport, storage and distribution that may be amenable to future intervention and improved removal of iron from important cellular sites are discussed, as are attempts to quantify quality of life and the importance of co-morbidities in measures to treat MDS, including chelation therapy.

A European survey on the detection and management of iron overload in transfusion-dependent patients with MDS

To better understand the detection and management of iron overload in transfusion-dependent patients with myelodysplastic syndromes (MDS), a 15-min web- or paper-based survey was conducted among 338 European physicians from 27 countries. Respondents had a mean of 18 years of clinical experience. Forty-six percent and 27% of physicians noted that detecting and treating iron overload were either “very important” or “important,” respectively. The main reason for not actively exploring iron overload was related to poor patient prognosis, while the main reasons for not initiating iron chelation therapy were poor patient prognosis and older patient age. Thirty-seven percent and 31% of physicians believed that treating iron overload in these patients was “very important” or “important,” respectively. Ninety percent of physicians prescribed iron chelation therapy, and 38% of transfusion-dependent patients received iron chelation therapy. The key reasons for not initiating iron chelation therapy were related to poor patient prognosis (72%), patient age ≥85 years (50%), and comorbidities (34%). The views of these experienced MDS physicians reflect available international MDS treatment guidelines.

Iron overload in MDS-pathophysiology, diagnosis, and complications

Many patients with myelodysplastic syndromes (MDS) become dependent on blood transfusions and develop transfusional iron overload, which is exacerbated by increased absorption of dietary iron in response to ineffective erythropoiesis. However, it is uncertain whether there is an association among iron accumulation, clinical complications, and decreased likelihood of survival in MDS patients. Here, we discuss our current understanding of the effects of transfusion dependency and iron overload in MDS, indicate our knowledge gaps, and suggest that particular emphasis should be placed on further characterizing the role of redox-active forms of labile iron, which may be as important as the total iron burden.

Iron overload in patients undergoing hematopoietic stem cell transplantation

Recipients of hematopoietic stem cell transplantation (HSCT) frequently have iron overload resulting from chronic transfusion therapy for anemia. In some cases, for example, in patients with myelodysplastic syndromes and thalassemia, this can be further exacerbated by increased absorption of iron from the gut as a result of ineffective erythropoiesis. Accumulating evidence has established the negative impact of elevated pretransplantation serum ferritin, a surrogate marker of iron overload, on overall survival and nonrelapse mortality after HSCT. Complications of HSCT associated with iron overload include increased bacterial and fungal infections as well as sinusoidal obstruction syndrome and possibly other regimen-related toxicities. Based on current evidence, particular attention should be paid to prevention and management of iron overload in allogeneic HSCT candidates, especially in patients with thalassemia and myelodysplastic syndromes. The pathophysiology of iron overload in the HSCT patient and optimum strategies to deal with iron overload during and after HSCT require further study.

Iron chelation therapy in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a heterogeneous disorder of the hematopoietic stem cells, frequently characterized by anemia and transfusion dependency. In low-risk patients, transfusion dependency can be long lasting, leading to iron overload. Iron chelation therapy may be a therapeutic option for these patients, especially since the approval of oral iron chelators, which are easier to use and better accepted by the patients. The usefulness of iron chelation in MDS patients is still under debate, mainly because of the lack of solid prospective clinical trials that should take place in the future. This review aims to summarize what is currently known about the incidence and clinical consequences of iron overload in MDS patients and the state-of the-art of iron chelation therapy in this setting. We also give an overview of clinical guidelines for chelation in MDS published to date and some perspectives for the future.

Iron overload in myelodysplastic syndromes: diagnosis and management

Myelodysplastic syndrome (MDS) is composed of a diverse spectrum of hematopoietic stem cell malignancies characterized by ineffective blood cell production. Many MDS patients are dependent on red blood cell (RBC) transfusions for symptomatic management of refractory anemia. Iron overload ensues when the iron acquired from transfused RBCs exceeds body storage capacity, thereby raising the risk for end organ damage. This is of greatest concern in patients with lower-risk MDS whose expected survival is measured in years. Transfusion dependence is associated with shorter survival and an increased risk for progression to acute myeloid leukemia (AML) in transfusion-dependent patients. Application of recent advances in the treatment of MDS can reduce or eliminate the need for transfusions, thus minimizing the risk of iron overload. Case control studies, prospective surveys, and phase II studies indicate that iron chelation therapy reduces iron load as measured by changes in serum ferritin and may prolong overall survival. Iron chelation strategies include oral agents such as deferasirox (Exjade, Novartis Pharmaceuticals Corp, East Hanover, NJ), deferiprone (Ferriprox, Apotex Europe BV, Leiden, the Netherlands) and, for those patients who are intolerant of or for whom oral therapy is ineffective, parenteral administration of deferoxamine (Desferal, Novartis). This review presents the data related to iron overload in MDS, including its prevalence, diagnosis, clinical impact, and management.

Iron chelation therapy in MDS: what have we learnt recently?

Patients with myelodysplastic syndromes (MDS) who receive chronic blood transfusions for anaemia are at risk of developing iron overload, which can negatively affect organ function and survival. Evidence suggests that iron chelation therapy can restore iron balance in these patients and may improve their chances of survival. Recently, several guidelines on the management of patients with MDS have been published that address iron overload and the use of iron chelation therapy. While these guidelines differ in some specific details, they generally agree that patients with lower-risk MDS are most likely to develop iron overload and therefore benefit from iron chelation therapy. The oral iron chelator, deferasirox, has been shown to reduce serum ferritin levels and labile plasma iron in patients with MDS, and has an acceptable safety profile. Unlike other iron chelators, deferasirox also appears to inhibit the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappaB) pathway in MDS blast cells, which may lead to additional beneficial effects.

Cost effectiveness of deferasirox compared to desferrioxamine in the treatment of iron overload in lower-risk, transfusion-dependent myelodysplastic syndrome patients

OBJECTIVE

The study evaluated the cost effectiveness of deferasirox (Exjade * ) compared to non-proprietary desferrioxamine (DFO) for the control of transfusional iron overload in lower risk myelodysplastic syndromes (MDS) patients. A UK National Health Service perspective was adopted.

METHODS

Recent clinical evidence has demonstrated the efficacy and safety of deferasirox in transfusion-dependent MDS patients with elevated serum ferritin levels. An economic model was used to extrapolate the clinical benefits of iron chelation therapy (ICT) in a cohort of lower risk MDS patients. Costs for drug acquisition, drug administration and monitoring, and quality of life (utility) outcomes associated with mode of drug administration were derived from a variety of sources. The incremental cost per QALY gained for deferasirox was estimated. Costs and outcomes were discounted at 3.5% in line with UK standards.

RESULTS

The base-case cost effectiveness of deferasirox versus DFO was estimated to be £20,822 per QALY gained, the key driver being the additional quality of life benefits associated with a simpler mode of administration for deferasirox. A mean survival benefit for both forms of ICT of 4.5 years was estimated. The results were sensitive to drug dose, days of DFO administration, and patient weight.

CONCLUSIONS

In the UK, a cost per QALY below £20,000-30,000 is considered cost effective. Hence, the results from this economic analysis suggest deferasirox is cost effective in lower risk, transfusion-dependent, MDS patients. Limitations with the analysis include a lack of comparative randomised controlled trial evidence, in particular to differentiate survival and clinical outcomes for deferasirox and DFO.

Deferasirox induces regression of iron overload in patients with myelodysplastic syndromes

BACKGROUND

Transfusion-related morbidity is an emerging problem in chronically transfused patients with myelodysplastic syndromes (MDS). Although several iron-chelating drugs are available, the optimal way of treatment of iron-overload remains uncertain. A major disadvantage of deferoxamine is that the drug has to be applied as continuous subcutaneous infusion. Therefore, novel oral agents have been developed. One of these drugs is deferasirox (Exjade).

MATERIALS AND METHODS

We report on 14 MDS patients who were treated with deferasirox (500-1500 mg daily) for up to 24 months. In these patients, treatment responses were recorded by determining serum ferritin levels before and during therapy and by applying recently established response criteria.

RESULTS

In all patients except one, ferritin levels decreased during therapy. Four patients showed a complete response, one a minor response and five a stable iron load. In the responding patients, initially elevated liver enzymes decreased substantially. No substantial change in transferrin saturation or transfusion frequency was recorded. Side effects were mild and tolerable in most patients. In one patient, treatment with deferasirox was stopped because of impaired kidney function.

CONCLUSION

Our data show that treatment with deferasirox is a reasonable approach to counteract iron overload in patients with MDS.

Recent Publications on Medications and Pharmacy

Hospital Pharmacy presents this feature to keep pharmacists abreast of new publications in the medical/pharmacy literature. Articles of interest regarding a broad scope of topics are abstracted monthly.