The safety and efficacy of ferumoxytol therapy in anemic chronic kidney disease patients

The Story of Ferumoxytol: Synthesis Production, Current Clinical Applications, and Therapeutic Potential

Ferumoxytol, approved by the U.S. Food and Drug Administration in 2009, is one of the intravenous iron oxide nanoparticles authorized for the treatment of iron deficiency in chronic kidney disease and end-stage renal disease. With its exceptional magnetic properties, catalytic activity, and immune activity, as well as good biocompatibility and safety, ferumoxytol has gained significant recognition in various biomedical diagnoses and treatments. Unlike most existing reviews on this topic, this review primarily focuses on the recent clinical and preclinical advances of ferumoxytol in disease treatment, spanning anemia, cancer, infectious inflammatory diseases, regenerative medicine application, magnetic stimulation for neural modulation, etc. Additionally, the newly discovered mechanisms associated with the biological effects of ferumoxytol are discussed, including its magnetic, catalytic, and immunomodulatory properties. Finally, the summary and future prospects concerning the treatment and application of ferumoxytol-based nanotherapeutics are presented.

How to stop using gadolinium chelates for magnetic resonance imaging: clinical-translational experiences with ferumoxytol

Gadolinium chelates have been used as standard contrast agents for clinical MRI for several decades. However, several investigators recently reported that rare Earth metals such as gadolinium are deposited in the brain for months or years. This is particularly concerning for children, whose developing brain is more vulnerable to exogenous toxins compared to adults. Therefore, a search is under way for alternative MR imaging biomarkers. The United States Food and Drug Administration (FDA)-approved iron supplement ferumoxytol can solve this unmet clinical need: ferumoxytol consists of iron oxide nanoparticles that can be detected with MRI and provide significant T1- and T2-signal enhancement of vessels and soft tissues. Several investigators including our research group have started to use ferumoxytol off-label as a new contrast agent for MRI. This article reviews the existing literature on the biodistribution of ferumoxytol in children and compares the diagnostic accuracy of ferumoxytol- and gadolinium-chelate-enhanced MRI. Iron oxide nanoparticles represent a promising new class of contrast agents for pediatric MRI that can be metabolized and are not deposited in the brain.

Repurposing ferumoxytol: Diagnostic and therapeutic applications of an FDA-approved nanoparticle

Ferumoxytol is an intravenous iron oxide nanoparticle formulation that has been approved by the U.S. Food and Drug Administration (FDA) for treating anemia in patients with chronic kidney disease. In recent years, ferumoxytol has also been demonstrated to have potential for many additional biomedical applications due to its excellent inherent physical properties, such as superparamagnetism, biocatalytic activity, and immunomodulatory behavior. With good safety and clearance profiles, ferumoxytol has been extensively utilized in both preclinical and clinical studies. Here, we first introduce the medical needs and the value of current iron oxide nanoparticle formulations in the market. We then focus on ferumoxytol nanoparticles and their physicochemical, diagnostic, and therapeutic properties. We include examples describing their use in various biomedical applications, including magnetic resonance imaging (MRI), multimodality imaging, iron deficiency treatment, immunotherapy, microbial biofilm treatment and drug delivery. Finally, we provide a brief conclusion and offer our perspectives on the current limitations and emerging applications of ferumoxytol in biomedicine. Overall, this review provides a comprehensive summary of the developments of ferumoxytol as an agent with diagnostic, therapeutic, and theranostic functionalities.

Magnetic Nanoparticles in Medicine: Progress, Problems, and Advances

The review presents an analysis of the current state of research related to the design, development, and practical application of methods for biomedical radioelectronics and nanomedicine, including the use of magnetic nanoparticles. The important role of rational scientific physical approaches and experimental methods in the design of efficient and safe magnetic nanoparticle-based agents for therapy, controlled targeted drug delivery, and diagnostics, including spatial imaging, is emphasized. Examples of successful practical application of magnetic nanoparticles in medicine based on these methods are given, and an analysis of the main problems and prospects of this area of science is conducted.

Can the biomolecular corona induce an allergic reaction?-A proof-of-concept study

Ferumoxytol nanoparticles are being used clinically for the treatment of anemia and molecular imaging in patients. It is well documented that while most patients tolerate ferumoxytol well, a small percentage of patients (i.e., 0.01%) develop severe allergic reactions. The purpose of our proof-of-concept study was to determine whether patients with or without hypersensitivity reactions have specific protein corona profiles around ferumoxytol nanoparticles. In a retrospective, institutional review board approved pilot study, we enrolled 13 pediatric patients (5 girls, 8 boys, mean age 16.9 ± 8.2 years) who received a ferumoxytol-enhanced magnetic resonance imaging and who did (group 1, n = 5) or did not (group 2, n = 8) develop an allergic reaction. Blood samples of these patients were incubated with ferumoxytol, and the formation of a hard protein corona around ferumoxytol nanoparticles was measured by dynamic light scattering, zeta potential, and liquid chromatography-mass spectrometry. We also performed in vitro immune response analyses to randomly selected coronas from each group. Our results provide preliminary evidence that ex vivo analysis of the biomolecular corona may provide useful and predictive information on the possibility of severe allergic reactions to ferumoxytol nanoparticles. In the future, patients with predisposition of an allergic reaction to ferumoxytol may be diagnosed based on the proteomic patterns of the corona around ferumoxytol in their blood sample.

Ferumoxytol-Enhanced MR Lymphography for Detection of Metastatic Lymph Nodes in Genitourinary Malignancies: A Prospective Study

OBJECTIVE. The objective of our study was to evaluate the utility of ferumoxytol-enhanced MR lymphography (MRL) in detection of metastatic lymph nodes (LNs) in patients with prostate, bladder, and kidney cancer. SUBJECTS AND METHODS. This phase 2 single-institution study enrolled patients with confirmed prostate (arm 1), bladder (arm 2), and kidney (arm 3) cancer and evidence of suspected LN involvement. Participants underwent ferumoxytol-enhanced MRL 24 and 48 hours after IV injection of 7.5 mg Fe/kg of ferumoxytol. A retrospective quantitative analysis was performed to determine the optimal timing for ferumoxytol-enhanced MRL using percentage change in normalized signal intensity (SI) from baseline to 24 and 48 hours after injection, which were estimated using the linear mixed-effects model in which time (24 vs 48 hours), diseases status, and time and disease status interaction were the fixed-effects independent variables. Differences in normalized SI values between subgroups of lesions were estimated by forming fixed-effects contrasts and tested by the Wald test. RESULTS. Thirty-nine patients (n = 30, arm 1; n = 6, arm 2; n = 3, arm 3) (median age, 65 years) with 145 LNs (metastatic, n = 100; benign, n = 45) were included. LN-based sensitivity, specificity, positive predictive value, and negative predictive value of ferumoxytol-enhanced MRL was 98.0%, 64.4%, 86.0%, and 93.5%, respectively. Sensitivity and specificity of ferumoxytol-enhanced MRL did not vary by LN size. Metastatic LNs showed a significantly higher percentage decrease of normalized SI on MRL at 24 hours after ferumoxytol injection than at 48 hours after ferumoxytol injection (p = 0.023), whereas the normalized SI values for nonmetastatic LNs were similar at both imaging time points (p = 0.260). CONCLUSION. Ferumoxytol-enhanced MRL shows high sensitivity in the detection of metastatic LNs in genitourinary cancers independent of LN size. The SI difference between benign and malignant LNs on ferumoxytol-enhanced MRL appears similar 24 and 48 hours after ferumoxytol injection, suggesting that imaging can be performed safely within 1 or 2 days of injection. Although ferumoxytol-enhanced MRL can be useful in settings without an available targeted PET agent, issues of iron overload and repeatability of ferumoxytol-enhanced MRL remain concerns for this method.

Comparison of ferumoxytol- and gadolinium chelate-enhanced MRI for assessment of sarcomas in children and adolescents

OBJECTIVES

We compared the value of ferumoxytol (FMX)- and gadolinium (Gd)-enhanced MRI for assessment of sarcomas in paediatric/adolescent patients and hypothesised that tumour size and morphological features can be equally well assessed with both protocols.

METHODS

We conducted a retrospective study of paediatric/adolescent patients with newly diagnosed bone or soft tissue sarcomas and both pre-treatment FMX- and Gd-MRI scans, which were maximal 4 weeks apart. Both protocols included T1- and T2-weighted sequences. One reader assessed tumour volumes, signal-to-noise ratios (SNR) of the primary tumour and adjacent tissues and contrast-to-noise ratios (CNR) of FMX- and Gd-MRI scans. Additionally, four readers scored FMX- and Gd-MRI scans according to 15 diagnostic parameters, using a Likert scale. The results were pooled across readers and compared between FMX- and Gd-MRI scans. Statistical methods included multivariate analyses with different models.

RESULTS

Twenty-two patients met inclusion criteria (16 males, 6 females; mean age 15.3 ± 5.0). Tumour volume was not significantly different on T1-LAVA (p = 0.721), T1-SE (p = 0.290) and T2-FSE (p = 0.609) sequences. Compared to Gd-MRI, FMX-MRI demonstrated significantly lower tumour SNR on T1-LAVA (p < 0.001), equal tumour SNR on T1-SE (p = 0.104) and T2-FSE (p = 0.305), significantly higher tumour-to-marrow CNR (p < 0.001) on T2-FSE as well as significantly higher tumour-to-liver (p = 0.021) and tumour-to-vessel (p = 0.003) CNR on T1-LAVA images. Peritumoural and marrow oedema enhanced significantly more on Gd-MRI compared to FMX-MRI (p < 0.001/p = 0.002, respectively). Tumour thrombi and neurovascular bundle involvement were assessed with a significantly higher confidence on FMX-MRI (both p < 0.001).

CONCLUSIONS

FMX-MRI provides equal assessment of the extent of bone and soft tissue sarcomas compared to Gd-MRI with improved tumour delineation and improved evaluation of neurovascular involvement and tumour thrombi. Therefore, FMX-MRI is a possible alternative to Gd-MRI for tumour staging in paediatric/adolescent sarcoma patients.

KEY POINTS

• Ferumoxytol can be used as an alterative to gadolinium chelates for MRI staging ofpaediatric sarcomas. • Ferumoxytol-enhanced MRI provides equal assessment of tumour size and other diagnostic parameters compared to gadolinium chelate-enhanced MRI. • Ferumoxytol-enhanced MRI provides improved delineation of sarcomas from bone marrow, liver and vessels compared to gadolinium chelate-enhanced MRI.

Nanopharmaceuticals and nanomedicines currently on the market: challenges and opportunities

There has been a revolution in nanotechnology and nanomedicine. Since 1980, there has been a remarkable increase in approved nano-based pharmaceutical products. These novel nano-based systems can either be therapeutic agents themselves, or else act as vehicles to carry different active pharmaceutical agents into specific parts of the body. Currently marketed nanostructures include nanocrystals, liposomes and lipid nanoparticles, PEGylated polymeric nanodrugs, other polymers, protein-based nanoparticles and metal-based nanoparticles. A range of issues must be addressed in the development of these nanostructures. Ethics, market size, possibility of market failure, costs and commercial development, are some topics which are on the table to be discussed. After passing all the ethical and biological assessments, and satisfying the investors as to future profitability, only a handful of these nanoformulations, successfully obtained marketing approval. We survey the range of nanomedicines that have received regulatory approval and are marketed. We discuss ethics, costs, commercial development and possible market failure. We estimate the global nanomedicine market size and future growth. Our goal is to summarize the different approved nanoformulations on the market, and briefly cover the challenges and future outlook.

Functional and Targeted Lymph Node Imaging in Prostate Cancer: Current Status and Future Challenges

Patients with prostate cancer who have regional lymph node (LN) metastases face an increased risk of death from disease and are therefore treated aggressively. Surgical LN dissection is the established method of staging regional nodes; however, this invasive technique carries substantial morbidities and a noninvasive imaging method is needed to reduce or eliminate the need for extended pelvic LN dissections (ePLND). Conventional computed tomography and magnetic resonance (MR) imaging have proven insensitive and nonspecific because both use nodal size criteria, which is notoriously inaccurate. Novel imaging techniques such as functional MR imaging by using diffusion-weighted MR imaging, MR lymphography with iron oxide particles, and targeted positron emission tomography imaging are currently under development and appear to improve LN staging of prostate cancer. Although progress is being made in staging nodes with imaging, it has not reached the point of replacing ePLND. In this review, the strengths and limitations of these new functional and targeted LN imaging techniques for prostate cancer are discussed. ^© RSNA, 2017.

One-Step Fast Synthesis of Nanoparticles for MRI: Coating Chemistry as the Key Variable Determining Positive or Negative Contrast

Iron oxide nanomaterial is a typical example of a magnetic resonance imaging probe for negative contrast. It has also been shown how this nanomaterial can be synthesized for positive contrast by modification of the composition and size of the core. However, the role of the organic coating in the relaxometric properties is largely unexplored. Here, maghemite nanoparticles with either excellent positive or very good negative contrast performance are obtained by modifying coating thickness while the core is kept unchanged. Different nanoparticles with tailored features as contrast agent according to the coating layer thickness have been obtained in a single-step microwave-driven synthesis by heating at different temperatures. A comprehensive analysis is conducted of how the composition and structure of the coating affects the final magnetic, relaxometric, and imaging performance. These results show how the organic coating plays a fundamental role in the intrinsic relaxometric parameters of iron oxide-based contrast media.

Intravenous Ferumoxytol in Pediatric Patients With Iron Deficiency Anemia

Background: Iron deficiency anemia (IDA) is common in children. Limited data exist on the efficacy and safety of ferumoxytol in children. Objective: To assess the efficacy of 10 mg/kg dose given over 15-60 minutes in correcting IDA and report any adverse drug reactions (ADRs). Methods: We conducted a retrospective review of all patients who received ferumoxytol infusions for the management of IDA by the Pediatric Blood Management Program between October 2010 and March 2015. Results: A total of 110 infusions were given to 54 patients. Compared with baseline preinfusion hemoglobin (Hb; 9.2 ± 1.9 g/dL), a significant rise was seen at 1 week and 4 weeks postinfusion (11.5 ± 1.5 and 11.8 ± 1.7 g/dL, respectively, P < 0.001). Also, a significant rise in serum ferritin at 1 week and 4 weeks postinfusion was seen (51 ± 71 vs 192 ± 148 and 89 ± 135 ng/mL, P < 0.001 and <0.035, respectively). Patients who concomitantly received erythropoietin had a significantly larger Hb rise from baseline than those who did not at 4 weeks (2.7 ± 2.2 vs 1.6 ± 1.1 g/dL, P < 0.017). ADRs included pruritus (n = 1), urticaria (n = 1), and multisymptom episodes (n = 3) that included shortness of breath, chest tightness, back pain, and epigastric cramping that responded to therapy with IV diphenhydramine and methylprednisolone. Conclusion: Ferumoxytol was effective in treating IDA in our small study. Slow infusion rate and close monitoring allowed early detection of the infrequent ADRs.

Detection of Stem Cell Transplant Rejection with Ferumoxytol MR Imaging: Correlation of MR Imaging Findings with Those at Intravital Microscopy

Purpose To determine whether endogenous labeling of macrophages with clinically applicable nanoparticles enables noninvasive detection of innate immune responses to stem cell transplants with magnetic resonance (MR) imaging. Materials and Methods Work with human stem cells was approved by the institutional review board and the stem cell research oversight committee, and animal experiments were approved by the administrative panel on laboratory animal care. Nine immunocompetent Sprague-Dawley rats received intravenous injection of ferumoxytol, and 18 Jax C57BL/6-Tg (Csf1r-EGFP-NGFR/FKBP1A/TNFRSF6) 2Bck/J mice received rhodamine-conjugated ferumoxytol. Then, 48 hours later, immune-matched or mismatched stem cells were implanted into osteochondral defects of the knee joints of experimental rats and calvarial defects of Jax mice. All animals underwent serial MR imaging and intravital microscopy (IVM) up to 4 weeks after surgery. Macrophages of Jax C57BL/6-Tg (Csf1r-EGFP-NGFR/FKBP1A/TNFRSF6) 2Bck/J mice express enhanced green fluorescent protein (GFP), which enables in vivo correlation of ferumoxytol enhancement at MR imaging with macrophage quantities at IVM. All quantitative data were compared between experimental groups by using a mixed linear model and t tests. Results Immune-mismatched stem cell implants demonstrated stronger ferumoxytol enhancement than did matched stem cell implants. At 4 weeks, T2 values of mismatched implants were significantly lower than those of matched implants in osteochondral defects of female rats (mean, 10.72 msec for human stem cells and 11.55 msec for male rat stem cells vs 15.45 msec for sex-matched rat stem cells; P = .02 and P = .04, respectively) and calvarial defects of recipient mice (mean, 21.7 msec vs 27.1 msec, respectively; P = .0444). This corresponded to increased recruitment of enhanced GFP- and rhodamine-ferumoxytol-positive macrophages into stem cell transplants, as visualized with IVM and histopathologic examination. Conclusion Endogenous labeling of macrophages with ferumoxytol enables noninvasive detection of innate immune responses to stem cell transplants with MR imaging. ^© RSNA, 2017 Online supplemental material is available for this article.

Imaging on nodal staging of prostate cancer

Prostate cancer is the second most common cancer in men and is the second highest cause of cancer death in men of all races. Accurate lymph node staging is essential to ensure adequate treatment of prostate cancer. Historically, conventional imaging methods have demonstrated limited sensitivity and specificity in the detection of lymph node metastases. There are many emerging PET tracers that have recently proven to be effective. In addition, the use of ultrasmall iron oxide nanoparticle-enhanced MRI has demonstrated promising results. This review outlines the strengths and limitations of each of the different imaging modalities as well as individual tracers used, including preclinical and clinical agents.

High-Density Lipoproteins: Nature's Multifunctional Nanoparticles

High-density lipoproteins (HDL) are endogenous nanoparticles involved in the transport and metabolism of cholesterol, phospholipids, and triglycerides. HDL is well-known as the "good" cholesterol because it not only removes excess cholesterol from atherosclerotic plaques but also has anti-inflammatory and antioxidative properties, which protect the cardiovascular system. Circulating HDL also transports endogenous proteins, vitamins, hormones, and microRNA to various organs. Compared with other synthetic nanocarriers, such as liposomes, micelles, and inorganic and polymeric nanoparticles, HDL has unique features that allow them to deliver cargo to specific targets more efficiently. These attributes include their ultrasmall size (8-12 nm in diameter), high tolerability in humans (up to 8 g of protein per infusion), long circulating half-life (12-24 h), and intrinsic targeting properties to different recipient cells. Various recombinant ApoA proteins and ApoA mimetic peptides have been recently developed for the preparation of reconstituted HDL that exhibits properties similar to those of endogenous HDL and has a potential for industrial scale-up. In this review, we will summarize (a) clinical pharmacokinetics and safety of reconstituted HDL products, (b) comparison of HDL with inorganic and other organic nanoparticles,

Nanoparticle-Based Therapies for Wound Biofilm Infection: Opportunities and Challenges

Clinical data from human chronic wounds implicates biofilm formation with the onset of wound chronicity. Despite the development of novel antimicrobial agents, the cost and complexity of treating chronic wound infections associated with biofilms remain a serious challenge, which necessitates the development of new and alternative approaches for effective anti-biofilm treatment. Recent advancement in nanotechnology for developing a new class of nanoparticles that exhibit unique chemical and physical properties holds promise for the treatment of biofilm infections. Over the last decade, nanoparticle-based approaches against wound biofilm infection have been directed toward developing nanoparticles with intrinsic antimicrobial properties, utilizing nanoparticles for controlled antimicrobials delivery, and applying nanoparticles for antibacterial hyperthermia therapy. In addition, a strategy to functionalize nanoparticles towards enhanced penetration through the biofilm matrix has been receiving considerable interest recently by means of achieving an efficient targeting to the bacterial cells within biofilm matrix. This review summarizes and highlights the recent development of these nanoparticle-based approaches as potential therapeutics for controlling wound biofilm infection, along with current challenges that need to be overcome for their successful clinical translation.

A Review of Clinical Translation of Inorganic Nanoparticles

Inorganic nanoparticles are widely used for therapeutic and diagnostic purposes as they offer unique features as compared with their organic and polymeric counterparts. As such, inorganic nanoparticles represent an exciting opportunity to develop drug delivery and imaging systems that are poised to tackle unique challenges which are currently unaddressed in clinical settings. Despite these clear advantages, very few inorganic nanoparticle systems have entered the clinic. Here, we review the current clinical landscape of inorganic nanoparticle systems and their opportunities and challenges, with particular emphasis on gold-, iron-oxide- and silica-based nanoparticle systems. Key examples of inorganic nanoparticles that are currently being investigated in the clinic (e.g., trials which are recruiting or currently active but not completed) are highlighted, along with the preclinical work that these examples have leveraged to transition from the lab to the clinic.

A Phase I Dosing Study of Ferumoxytol for MR Lymphography at 3 T in Patients With Prostate Cancer

OBJECTIVE

The objective of our study was to determine the optimal dose of ferumoxytol for performing MR lymphography (MRL) at 3 T in patients with prostate cancer.

SUBJECTS AND METHODS

This phase I trial enrolled patients undergoing radical prostatectomy (RP) with bilateral pelvic lymph node dissection (PLND). Three groups of five patients each (total of 15 patients) received IV ferumoxytol before RP with bilateral PLND at each of the following doses of iron: 4, 6, and 7.5 mg Fe/kg. Patients underwent abdominopelvic MRI at 3 T before and 24 hours after ferumoxytol injection using T2- and T2*-weighted sequences. Normalized signal intensity (SI) and normalized SD changes from baseline to 24 hours after injection within visible lymph nodes were calculated for each dose level. Linear mixed effects models were used to estimate the effects of dose on the percentage SI change and log-transformed SD change within visible lymph nodes to determine the optimal dose of ferumoxytol for achieving uniform low SI in normal nodes.

RESULTS

One patient who was excluded from the study group had a mild allergic reaction requiring treatment after approximately 2.5 mg Fe/kg ferumoxytol injection whereupon the injection was interrupted. The 15 study group patients tolerated ferumoxytol at all dose levels. The mean percentage SI change in 13 patients with no evidence of lymph metastasis was -36.4%, -45.4%, and -65.1% for 4, 6, and 7.5 mg Fe/kg doses, respectively (p = 0.041).

CONCLUSION

A dose level of 7.5 mg Fe/kg ferumoxytol was safe and effective in deenhancing benign lymph nodes. This dose therefore can be the starting point for future phase II studies regarding the efficacy of ferumoxytol for MRL.

A Review of Clinical Translation of Inorganic Nanoparticles

Inorganic nanoparticles are widely used for therapeutic and diagnostic purposes as they offer unique features as compared with their organic and polymeric counterparts. As such, inorganic nanoparticles represent an exciting opportunity to develop drug delivery and imaging systems that are poised to tackle unique challenges which are currently unaddressed in clinical settings. Despite these clear advantages, very few inorganic nanoparticle systems have entered the clinic. Here, we review the current clinical landscape of inorganic nanoparticle systems and their opportunities and challenges, with particular emphasis on gold-, iron-oxide- and silica-based nanoparticle systems. Key examples of inorganic nanoparticles that are currently being investigated in the clinic (e.g., trials which are recruiting or currently active but not completed) are highlighted, along with the preclinical work that these examples have leveraged to transition from the lab to the clinic.

Lymph node staging in prostate cancer

Nodal staging is important in prostate cancer treatment. While surgical lymph node dissection is the classic method of determining whether lymph nodes harbor malignancy, this is a very invasive technique. Current noninvasive approaches to identifying malignant lymph nodes are limited. Conventional imaging methods rely on size and morphology of lymph nodes and have notoriously low sensitivity for detecting malignant nodes. New imaging techniques such as targeted positron emission tomography (PET) imaging and magnetic resonance lymphography (MRL) with iron oxide particles are promising for nodal staging of prostate cancer. In this review, the strengths and limitations of imaging techniques for lymph node staging of prostate cancer are discussed.

Population pharmacokinetic meta-analysis to bridge ferumoxytol plasma pharmacokinetics across populations

BACKGROUND

Ferumoxytol is approved for the treatment of iron-deficiency anaemia (IDA) in adult patients with chronic kidney disease (CKD). Ferumoxytol has recently been investigated for use in all-cause IDA. This analysis was employed to bridge ferumoxytol pharmacokinetics (PK) across populations of healthy subjects and patients with CKD on haemodialysis, and to then make informed inferences regarding the PK behaviour of ferumoxytol in the all-cause IDA population.

METHODS

The data analysis was performed using NONMEM. Selected parameters were included for covariate testing. Investigations to determine if changes in volume of distribution during haemodialysis improved the model fit were also conducted. The final model was used to simulate PK in healthy volunteers (HVs) and CKD patients with and without haemodialysis.

RESULTS

The final model was a two-compartment model with non-linear elimination. During haemodialysis, the central volume V1 was estimated to be reduced by 0.198 L/h. A positive relationship was identified between initial V1 and observed weight loss during haemodialysis. V1 increased by 0.614 % per kilogram of body weight, and females had an 18.3 % lower V1 than males. Differences between simulated profiles for different populations were marginal: maximum concentration (Cmax) of 209 vs. 204 ng/mL and area under the curve from time zero to infinity (AUCinf) of 5,980 vs. 5,920 ng·h/mL in HVs and CKD non-haemodialysis patients, respectively, for a single dose of 510 mg.

CONCLUSIONS

The results indicate that ferumoxytol PK are comparable between HVs and CKD patients. Furthermore, the results are representative of the PK in other populations and can be used to bridge to subjects with general IDA.

Nanopharmaceuticals (part 2): products in the pipeline

In part I of this review we assessed nanoscience-related definitions as applied to pharmaceuticals and we discussed all 43 currently approved drug formulations, which are widely publicized as nanopharmaceuticals or nanomedicines. In continuation, here we review the currently ongoing clinical trials within the broad field of nanomedicine. Confining the definition of nanopharmaceuticals to therapeutic formulations, in which the unique physicochemical properties expressed in the nanosize range, when man-made, play the pivotal therapeutic role, we found an apparently low number of trials, which reflects neither the massive investments made in the field of nanomedicine nor the general hype associated with the term "nano." Moreover, after an extensive search for information through clinical trials, we found only two clinical trials with materials that show unique nano-based properties, ie, properties that are displayed neither on the atomic nor on the bulk material level.

Cancer nanotherapeutics in clinical trials

To be legally sold in the United States, all drugs must go through the FDA approval process. This chapter introduces the FDA approval process and describes the clinical trials required for a drug to gain approval. We then look at the different cancer nanotherapeutics and in vivo diagnostics that are currently in clinical trials or have already received approval. These nanotechnologies are catagorized and described based on the delivery vehicle: liposomes, polymer micelles, albumin-bound chemotherapeutics, polymer-bound chemotherapeutics, and inorganic particles.

Update on intravenous iron choices

PURPOSE OF REVIEW

Iron deficiency is a major factor in the prevalence and severity of anemia in patients with chronic kidney disease (CKD). We review the pathophysiology impairing normal intestinal iron absorption in CKD and compare the characteristics of newer intravenous (i.v.) iron agents to the longstanding i.v. iron products in the market.

RECENT FINDINGS

The newer iron products, ferumoxytol, ferric carboxymaltose, and iron isomaltoside, more avidly bind iron, minimizing the release of labile iron during infusions, thus permitting large dose infusions. These irons also have more complex carbohydrate shells than their predecessors, which may also diminish reactions. Newer agents can be routinely administered at higher single doses, in as little as 15 min, with an acceptable safety profile.

SUMMARY

Newer i.v. iron products permit the rapid, and sometimes complete, repletion of iron-deficient patients with a single dose. However, further studies examining the long-term risks and benefits of i.v. iron repletion are needed.

A Phase III, randomized, open-label trial of ferumoxytol compared with iron sucrose for the treatment of iron deficiency anemia in patients with a history of unsatisfactory oral iron therapy

Iron deficiency anemia (IDA) is the most common form of anemia worldwide. Although oral iron is used as first-line treatment, many patients are unresponsive to or cannot take oral iron. This Phase III, open-label, non-inferiority study compared the efficacy and safety of ferumoxytol, a rapid, injectable intravenous (IV) iron product with low immunological reactivity and minimal detectable free iron, with IV iron sucrose in adults with IDA of any cause. Patients (N = 605) were randomized 2:1 to receive ferumoxytol (n = 406, two doses of 510 mg 5 ± 3 days apart) or iron sucrose (n = 199, five doses of 200 mg on five nonconsecutive days over 14 days) and followed for 5 weeks. Ferumoxytol demonstrated noninferiority to iron sucrose at the primary endpoint, the proportion of patients achieving a hemoglobin increase of ≥2 g dL⁻¹ at any time from Baseline to Week 5 (ferumoxytol, 84.0% [n = 406] vs. iron sucrose, 81.4% [n = 199]), with a noninferiority margin of 15%. Ferumoxytol was superior to iron sucrose (2.7 g dL⁻¹ vs. 2.4 g dL⁻¹) in the mean change in hemoglobin from Baseline to Week 5 (the alternative preplanned primary endpoint) with P = 0.0124. Transferrin saturation, quality-of-life measures, and safety outcomes were similar between the two treatment groups. Overall, ferumoxytol demonstrated comparable safety and efficacy to iron sucrose, suggesting that ferumoxytol may be a useful treatment option for patients with IDA in whom oral iron was unsatisfactory or could not be used. Am. J. Hematol. 89:646–650, 2014. © 2014 Wiley Periodicals, Inc.

Efficacy and safety of IV ferumoxytol for adults with iron deficiency anemia previously unresponsive to or unable to tolerate oral iron

Although oral iron is the initial treatment approach for iron deficiency anemia (IDA), some patients fail to respond to or cannot tolerate oral iron. This double-blind safety and efficacy study of the intravenous (IV) iron, ferumoxytol, randomized patients with a history of unsatisfactory oral iron therapy, or in whom oral iron could not be used, to ferumoxytol (n = 609) or placebo (n = 203). The proportion of patients achieving the primary endpoint (hemoglobin increase ≥2.0 g/dL at Week 5) was 81.1% with ferumoxytol versus 5.5% with placebo (P < 0.0001). The mean increase in hemoglobin from Baseline to Week 5, a secondary endpoint (also the alternative preplanned primary efficacy endpoint for other health authorities), was 2.7 versus 0.1 g/dL (P < 0.0001). Achievement of a hemoglobin ≥12 g/dL, time to a hemoglobin increase ≥2.0 g/dL, and improvement in the Functional Assessment of Chronic Illness Therapy Fatigue score also significantly favored ferumoxytol over placebo at Week 5 (P < 0.0001). Ferumoxytol treatment-emergent adverse events were mainly mild to moderate. Ferumoxytol was effective and well tolerated in patients with IDA of any underlying cause in whom oral iron was ineffective or could not be used. This trial was registered at www.clinicaltrials.gov as #NCT01114139.

Iron administration before stem cell harvest enables MR imaging tracking after transplantation

PURPOSE

To determine whether intravenous ferumoxytol can be used to effectively label mesenchymal stem cells (MSCs) in vivo and can be used for tracking of stem cell transplants.

MATERIALS AND METHODS

This study was approved by the institutional animal care and use committee. Sprague-Dawley rats (6-8 weeks old) were injected with ferumoxytol 48 hours prior to extraction of MSCs from bone marrow. Ferumoxytol uptake by these MSCs was evaluated with fluorescence, confocal, and electron microscopy and compared with results of traditional ex vivo-labeling procedures. The in vivo-labeled cells were subsequently transplanted in osteochondral defects of 14 knees of seven athymic rats and were evaluated with magnetic resonance (MR) imaging up to 4 weeks after transplantation. T2 relaxation times of in vivo-labeled MSC transplants and unlabeled control transplants were compared by using t tests. MR data were correlated with histopathologic results.

RESULTS

In vivo-labeled MSCs demonstrated significantly higher ferumoxytol uptake compared with ex vivo-labeled cells. With electron microscopy, iron oxide nanoparticles were localized in secondary lysosomes. In vivo-labeled cells demonstrated significant T2 shortening effects in vitro and in vivo when they were compared with unlabeled control cells (T2 in vivo, 15.4 vs 24.4 msec; P < .05) and could be tracked in osteochondral defects for 4 weeks. Histologic examination confirmed the presence of iron in labeled transplants and defect remodeling.

CONCLUSION

Intravenous ferumoxytol can be used to effectively label MSCs in vivo and can be used for tracking of stem cell transplants with MR imaging. This method eliminates risks of contamination and biologic alteration of MSCs associated with ex vivo-labeling procedures.

Ferumoxytol: in iron deficiency anaemia in adults with chronic kidney disease

Ferumoxytol is an intravenously administered iron preparation indicated in the EU and the US for the treatment of iron deficiency anaemia in adult patients with chronic kidney disease (CKD). It consists of superparamagnetic iron oxide nanoparticles coated with a semi-synthetic carbohydrate shell in an isotonic, neutral pH solution that can be administered at relatively high dose by rapid intravenous injection. In phase III, randomized, controlled trials, two doses of ferumoxytol (510 mg iron/dose) given 2-8 days apart increased mean haemoglobin levels from baseline to week 5 significantly more than oral iron (200 mg/day for 21 days) in adult patients with iron deficiency anaemia and CKD stages 1-5. Ferumoxytol was more effective than oral iron both in patients with non-dialysis-dependent CKD and in those with haemodialysis-dependent CKD. Ferumoxytol was generally well tolerated in randomized controlled clinical trials. Most adverse events were mild or moderate in intensity; serious hypersensitivity or hypotensive reactions were uncommon. Local injection-site reactions were the most common system/organ-class adverse events in a pooled analysis of clinical studies and post-marketing experience.

Magnetic nanoparticle targeted hyperthermia of cutaneous Staphylococcus aureus infection

The incidence of wound infections that do not adequately respond to standard-of-care antimicrobial treatment has been increasing. To address this challenge, a novel antimicrobial magnetic thermotherapy platform has been developed in which a high-amplitude, high-frequency, alternating magnetic field is used to rapidly heat magnetic nanoparticles that are bound to Staphylococcus aureus (S. aureus). The antimicrobial efficacy of this platform was evaluated in the treatment of both an in vitro culture model of S. aureus biofilm and a mouse model of cutaneous S. aureus infection. We demonstrated that an antibody-targeted magnetic nanoparticle bound to S. aureus was effective at thermally inactivating S. aureus and achieving accelerated wound healing without causing tissue injury.

Ferumoxytol: a silver lining in the treatment of anemia of chronic kidney disease or another dark cloud?

Intravenous iron therapy is pivotal in the treatment of anemia of chronic kidney disease to optimize the response of hemoglobin to erythropoiesis-stimulating agents. Intravenous iron use in patients with chronic kidney disease is on the rise. Recent clinical trial data prompting safety concerns regarding the use of erythropoiesis-stimulating agents has stimulated new US Food and Drug Administration label changes and restrictions for these agents, and has encouraged more aggressive use of intravenous iron. The currently available intravenous iron products differ with regard to the stability of the iron-carbohydrate complex and potential to induce hypersensitivity reactions. Ferumoxytol is a newer large molecular weight intravenous iron formulation that is a colloidal iron oxide nanoparticle suspension coated with polyglucose sorbitol carboxymethyl ether. Ferumoxytol has robust iron-carbohydrate complex stability with minimal dissociation or appearance of free iron in the serum, allowing the drug to be given in relatively large doses with a rapid rate of administration. Clinical trials have demonstrated the superior efficacy of ferumoxytol versus oral iron with minimal adverse effects. However, recent postmarketing data have demonstrated a risk of hypersensitivity that has prompted new changes to the product information mandated by the Food and Drug Administration. Additionally, the long-term safety of this agent has not been evaluated, and its place in the treatment of anemia of chronic kidney disease has not been fully elucidated.

USPIO-enhanced MR angiography of arteriovenous fistulas in patients with renal failure

PURPOSE

To determine the feasibility of using ferumoxytol-enhanced magnetic resonance (MR) angiography to depict the vasculature of hemodialysis fistulas and improve image quality compared with nonenhanced time-of-flight (TOF) MR angiography.

MATERIALS AND METHODS

The study was institutional review board approved and was in compliance with HIPAA regulations. All participants provided written informed consent. TOF and first-pass ferumoxytol-enhanced MR angiography were performed in 10 patients with upper extremity autogenous fistulas. Ferumoxytol was administered as a bolus solution containing 430 μmol of elemental iron. A qualitative comparison was performed on maximum intensity projection images. Lumen depiction was evaluated by using a five-point scale. The uniformity of intraluminal signal intensity was measured as the ratio between the mean signal intensity of the entirety of the imaged fistula and its standard deviation. The contrast-to-noise ratio (CNR) between intraluminal signal and adjacent tissue was evaluated as a function of image acquisition time. Lumen depiction scores, luminal signal heterogeneity, and CNR efficiency were compared between TOF and ferumoxytol-enhanced MR angiography by using a Wilcoxon-Mann-Whitney test.

RESULTS

Flow artifacts were greatly reduced by the use of ferumoxytol-enhanced MR angiography. Ferumoxytol-enhanced MR angiography had significantly better performance than TOF MR angiography as measured with the following: lumen depiction scores in all segments (mean, 4.7±0.1 [standard error of the mean]; vs 3.0±0.3 for arterial inflow, 4.1±0.3 vs 1.9±0.3 for arterial outflow, 3.7±0.3 vs 1.8±0.2 for anastomosis, and 4.5±0.2 vs 2.1±0.2 for venous outflow; P<.001), intraluminal signal homogeneity (0.3±0.02 vs 0.4±0.06, P=.005), and CNR efficiency in the venous outflow (5.1±0.6 vs 2.5±0.4, P=.01).

CONCLUSION

This study demonstrates the feasibility of using ferumoxytol-enhanced MR angiography in imaging hemodialysis fistulas with consistently superior image quality compared with nonenhanced TOF MR angiography.

Ferumoxytol for the treatment of iron deficiency

Intravenous iron is standard for dialysis-associated anemia and its use is rising dramatically in other settings. Except for the dextrans, full iron replacement requires multiple visits. Nonetheless, safety concerns abound. Ferumoxytol, a recently approved modified dextran with a carbohydrate core that tightly binds the iron moiety, decreasing free iron and ostensibly increasing safety, was approved by the US FDA, in June 2009, for the treatment of iron deficiency associated with chronic kidney disease and end-stage renal disease. This formulation, uniquely, can be administered in a large dose as a short intravenous injection of 1 min or less, markedly facilitating care. Recent post-marketing safety issues have been raised resulting in a change in the package insert. This article examines existing clinical data and posits reasons for the labeling change. Potential future use of this formulation is opined.

Accelerated total dose infusion of low molecular weight iron dextran is safe and efficacious in chronic kidney disease patients

BACKGROUND

Low molecular weight iron dextran (LMWID) is licensed for use as a total dose infusion (TDI) over 4-6 h. In order to improve patient convenience and cost-effectiveness of therapy, we investigated the safety and efficacy of adopting accelerated dosing regimens and compared this with a standard rate LMWID infusion.

METHODS

A retrospective study of patients undergoing accelerated and standard rate TDI of LMWID was conducted across three centres. A total of 1904 doses of LMWID were administered at an accelerated rate of 1 g over 1 h 40 min. This was compared with 395 patients who had standard rate infusion of 1 g LMWID over 3-4 h.

RESULTS

There were eight minor adverse events in patients receiving accelerated dose LMWID (8/1904, 0.42%) in comparison to one adverse event in patients receiving a standard regimen (1/395, 0.25%). No serious adverse events occurred. Serum haemoglobin and ferritin significantly improved in both groups.

CONCLUSION

TDI LMWID is a safe and efficacious method of iron replacement. Accelerated infusion regimen is safe and compares well with standard rate infusion regimen. Furthermore, accelerated TDI of LMWID enables greater numbers of patients to be treated and consequently there appear to be advantages for both patient and health resources.

Plasma pharmacokinetics of two consecutive doses of ferumoxytol in healthy subjects

Intravenous (IV) iron is used to treat iron-deficiency anemia in patients with chronic kidney disease (CKD). Ferumoxytol is a novel iron formulation administered rapidly as two IV boluses of 510 mg each. In this placebo-controlled, double-blind, parallel-group study, 58 healthy volunteers received ferumoxytol in two 510 mg doses administered 24 h apart. Population pharmacokinetics (PK) analysis was conducted, and a two-compartment open model with zero-order input and Michaelis-Menten elimination was found to best describe the data. The population mean estimates for volume of distribution of the central compartment (V(1)), maximal elimination rate (V(max)), and ferumoxytol concentration at which rate of metabolism would be one-half of V(max) (K(m)) were 2.71 l, 14.3 mg/h, and 77.5 mg/l, respectively. When the effect of body weight on V(1) was added in the analysis, interindividual variability was found to be reduced. A noncompartmental analysis of two simulated 510-mg ferumoxytol doses was also performed to provide clinically interpretable data on half life and exposure. Ferumoxytol given as two consecutive 510-mg doses was well tolerated.

Parenteral iron formulations differentially affect MCP-1, HO-1, and NGAL gene expression and renal responses to injury

Despite their prooxidant effects, ferric iron compounds are routinely administered to patients with renal disease to correct Fe deficiency. This study assessed relative degrees to which three clinically employed Fe formulations [Fe sucrose (FeS); Fe gluconate (FeG); ferumoxytol (FMX)] impact renal redox- sensitive signaling, cytotoxicity, and responses to superimposed stress [endotoxin; glycerol-induced acute renal failure (ARF)]. Cultured human proximal tubule (HK-2) cells, isolated proximal tubule segments (PTS), or mice were exposed to variable, but equal, amounts of FeS, FeG, or FMX. Oxidant-stimulated signaling was assessed by heme oxygenase-1 (HO-1) or monocyte chemoattractant protein (MCP)-1 mRNA induction. Cell injury was gauged by MTT assay (HK-2 cells), %LDH release (PTS), or renal cortical neutrophil gelatinase-associated lipoprotein (NGAL) protein/mRNA levels. Endotoxin sensitivity and ARF severity were assessed by TNF-alpha and blood urea nitrogen concentrations, respectively. FeS and FeG induced lethal cell injury (in HK-2 cells, PTS), increased HO-1 and MCP-1 mRNAs (HK-2 cells; in vivo), and markedly raised plasma ( approximately 10 times), and renal cortical ( approximately 3 times) NGAL protein levels. Both renal and extrarenal (e.g., hepatic) NGAL production likely contributed to these results, based on assessments of tissue and HK-2 cell NGAL mRNA. FeS pretreatment exacerbated endotoxemia. However, it conferred marked protection against the glycerol model of ARF (halving azotemia). FMX appeared to be "bioneutral," as it exerted none of the above noted FeS/FeG effects. We conclude that 1) parenteral iron formulations that stimulate redox signaling can evoke cyto/nephrotoxicity; 2) secondary adaptive responses to this injury (e.g., HO-1/NGAL induction) can initiate a renal tubular cytoresistant state; this suggests a potential new clinical application for intravenous Fe therapy; and 3) FMX is bioneutral regarding these responses. The clinical implication(s) of the latter, vis a vis the treatment of Fe deficiency in renal disease patients, remains to be defined.

Anaphylaxis with elevated serum tryptase after administration of intravenous ferumoxytol

Ferumoxytol is a newly approved preparation of intravenous iron with a modified dextran shell that is thought to confer upon it a low immunogenic potential. Serious adverse reactions have been very uncommon in clinical studies, but these studies excluded patients with prior adverse reactions to other preparations of intravenous iron. Furthermore, the reactions were classified clinically. We report on a patient with a history of hypersensitivity to iron dextran who experienced an anaphylactic reaction after receiving ferumoxytol. Laboratory testing revealed an elevated serum tryptase level, confirming mast cell activation. This is the first laboratory-proven case of anaphylaxis related to ferumoxytol.

Ferumoxytol: a new intravenous iron preparation for the treatment of iron deficiency anemia in patients with chronic kidney disease

Ferumoxytol is an intravenous iron preparation for treatment of the anemia of chronic kidney disease (CKD). It is a carbohydrate-coated, superparamagnetic iron oxide nanoparticle. Because little free iron is present in the preparation, doses of 510 mg have been administered safely in as little as 17 seconds. Two prospective, randomized studies compared two doses of ferumoxytol 510 mg given in 5 +/- 3 days with 3 weeks of oral iron 200 mg/day (as ferrous fumarate) in anemic patients with CKD. One study enrolled 304 patients with stages 1-5 CKD (predialysis), and the other study enrolled 230 patients with stage 5D CKD (undergoing hemodialysis). In both studies, a greater increase in hemoglobin level from baseline to end of study (day 35) was noted in patients who received ferumoxytol compared with those who received oral iron (mean +/- SD 0.82 +/- 1.24 vs 0.16 +/- 1.02 g/dl in patients with stages 1-5 CKD and 1.02 +/- 1.13 vs 0.46 +/- 1.06 g/dl in patients with stage 5D CKD, p<0.001). A greater proportion of both predialysis and hemodialysis patients who received ferumoxytol had hemoglobin level increases from baseline of 1 g/dl or more compared with those who received oral iron (p<0.001). In a prospective, double-blind, crossover study of more than 700 patients with CKD stages 1-5D that compared the safety of ferumoxytol with normal saline injection, the rates of treatment-related adverse events were 5.2% and 4.5%, respectively. Serious treatment-related adverse events were seen in one patient in each treatment group. The most common adverse events with ferumoxytol occurred at the injection site (bruising, pain, swelling, erythema). Dizziness, nausea, pruritus, headache, and fatigue occurred in less than 2% of patients receiving ferumoxytol, with a similar frequency noted after administration of normal saline. In short-term studies, intravenous ferumoxytol was safely and rapidly administered, and was more effective than oral iron therapy in increasing hemoglobin levels in anemic patients with CKD. Long-term clinical trials with clinical outcomes and studies comparing ferumoxytol with other parenteral iron agents will help define the role of ferumoxytol in treating the anemia of CKD.

Superparamagnetic iron oxide nanoparticles: diagnostic magnetic resonance imaging and potential therapeutic applications in neurooncology and central nervous system inflammatory pathologies, a review

Superparamagnetic iron oxide nanoparticles have diverse diagnostic and potential therapeutic applications in the central nervous system (CNS). They are useful as magnetic resonance imaging (MRI) contrast agents to evaluate: areas of blood-brain barrier (BBB) dysfunction related to tumors and other neuroinflammatory pathologies, the cerebrovasculature using perfusion-weighted MRI sequences, and in vivo cellular tracking in CNS disease or injury. Novel, targeted, nanoparticle synthesis strategies will allow for a rapidly expanding range of applications in patients with brain tumors, cerebral ischemia or stroke, carotid atherosclerosis, multiple sclerosis, traumatic brain injury, and epilepsy. These strategies may ultimately improve disease detection, therapeutic monitoring, and treatment efficacy especially in the context of antiangiogenic chemotherapy and antiinflammatory medications. The purpose of this review is to outline the current status of superparamagnetic iron oxide nanoparticles in the context of biomedical nanotechnology as they apply to diagnostic MRI and potential therapeutic applications in neurooncology and other CNS inflammatory conditions.

Ferumoxytol as an intravenous iron replacement therapy in hemodialysis patients

BACKGROUND AND OBJECTIVES

Intravenous iron is a key component of anemia management for chronic kidney disease (CKD). Ferumoxytol is a unique intravenous iron product that can be administered as a rapid injection in doses up to 510 mg.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a randomized, open-label, controlled, multicenter Phase 3 trial to evaluate the safety and efficacy of intravenous ferumoxytol compared with oral iron. Anemic patients with CKD stage 5D on hemodialysis and on a stable erythropoiesis-stimulating agent regimen received either two injections of 510 mg of ferumoxytol within 7 d (n = 114) or 200 mg elemental oral iron daily for 21 d (n = 116). The primary efficacy endpoint was the change in hemoglobin from baseline to day 35. Safety was closely monitored.

RESULTS

Ferumoxytol resulted in a mean increase in hemoglobin of 1.02 +/- 1.13 g/dl at day 35 compared with 0.46 +/- 1.06 g/dl with oral iron (P = 0.0002). Twice as many ferumoxytol-treated patients than oral iron-treated patients achieved a > or =1 g/dl hemoglobin increase at day 35 (P = 0.0002). There was a greater mean increase in transferrin saturation (TSAT) with ferumoxytol compared with oral iron at day 35 (P < 0.0001). The larger hemoglobin increase after ferumoxytol compared with oral iron at day 35 persisted after adjustment for baseline hemoglobin, TSAT, and serum ferritin. Overall adverse event rates were comparable between groups.

CONCLUSIONS

In patients on hemodialysis, rapid intravenous injection of 510 mg of ferumoxytol led to significantly greater hemoglobin increases compared with oral iron, with comparable tolerability.

Challenges in the development of magnetic particles for therapeutic applications

Certain iron-based particle formulations have useful magnetic properties that, when combined with low toxicity and desirable pharmacokinetics, encourage their development for therapeutic applications. This mini-review begins with background information on magnetic particle use as MRI contrast agents and the influence of material size on pharmacokinetics and tissue penetration. Therapeutic investigations, including (1) the loading of bioactive materials, (2) the use of stationary, high-gradient (HG) magnetic fields to concentrate magnetic particles in tissues or to separate material bound to the particles from the body, and (3) the application of high power alternating magnetic fields (AMF) to generate heat in magnetic particles for hyperthermic therapeutic applications are then surveyed. Attention is directed mainly to cancer treatment, as selective distribution to tumors is well-suited to particulate approaches and has been a focus of most development efforts. While magnetic particles have been explored for several decades, their use in therapeutic products remains minimal; a discussion of future directions and potential ways to better leverage magnetic properties and to integrate their use into therapeutic regimens is discussed.

Serum Ferritin: Deceptively Simple or Simply Deceptive? Lessons Learned From Iron Therapy in Patients With Chronic Kidney Disease

Iron is an essential micronutrient that is indispensable for erythropoesis. Correct assessment of iron stores is needed both for the diagnosis of iron deficiency and to direct iron replacement therapies. Serum ferritin is a commonly employed measure to assess iron stores, yet there are caveats that influence its accuracy as a diagnostic tool. While low ferritin levels are specific for iron deficiency, high levels can be the result of inflammation, liver disease, or malignancies and could be independent of iron stores. Optimal anemia management involves administration of adequate amounts of iron. The right dose of iron that allows optimal erythropoesis yet avoids oxidative stress is a matter of ongoing debate, especially when using imperfect diagnostic tools such as serum ferritin to direct therapy. Data from hemodialysis patients are presented to illustrate the challenges one faces when trying to achieve the best possible therapeutic benefit from iron-replacement therapy.

Safety of ferumoxytol in patients with anemia and CKD

BACKGROUND

Iron deficiency anemia is a common complication in patients with chronic kidney disease (CKD). Currently available intravenous (IV) iron replacement therapies have either inconvenient regimens of administration or adverse event profiles that limit their utility in the outpatient setting. Ferumoxytol is a novel, semisynthetic, carbohydrate-coated, superparamagnetic iron oxide nanoparticle that is administered IV as an injection. The main objective of this study was to assess the safety of ferumoxytol for the treatment of patients with CKD stages 1 to 5 and 5D.

STUDY DESIGN

Phase 3, randomized, double-blind, placebo-controlled, crossover, multicenter study of a single 510-mg dose of ferumoxytol versus saline as placebo.

SETTING & PARTICIPANTS

750 patients with CKD stages 1 to 5 and 5D.

INTERVENTION

An IV injection of either 17 mL of ferumoxytol or saline placebo over 17 seconds on day 0 and the alternate agent on day 7.

OUTCOMES & MEASUREMENTS

Descriptive comparison of adverse events, laboratory tests, and vital signs.

RESULTS

Of 750 randomly assigned patients with CKD, 60% were not on dialysis therapy. 713 patients received ferumoxytol, and 711 received placebo. There were 420 adverse events reported; 242 in 152 patients (21.3%) with ferumoxytol and 178 in 119 patients (16.7%) with placebo. The incidence of related adverse events was 5.2% with ferumoxytol and 4.5% with placebo. The most common related adverse events after each treatment included symptoms related to the injection/infusion site, dizziness, pruritus, headache, fatigue, and nausea. Serious adverse events occurred in 21 patients (2.9%) after ferumoxytol and 13 patients (1.8%) after placebo. Serious related adverse events were observed in 1 patient (0.1%) after each treatment. There was no meaningful decrease in blood pressure after administration of ferumoxytol or placebo.

LIMITATIONS

Follow-up was 7 days after each study treatment.

CONCLUSIONS

Ferumoxytol is well tolerated and has a safety profile similar to placebo in anemic patients with CKD stages 1 to 5 and 5D.

Ferumoxytol for treating iron deficiency anemia in CKD

Iron deficiency is an important cause of anemia in patients with chronic kidney disease (CKD), but intravenous iron is infrequently used among patients who are not on dialysis. Ferumoxytol is a novel intravenous iron product that can be administered as a rapid injection. This Phase III trial randomly assigned 304 patients with CKD in a 3:1 ratio to two 510-mg doses of intravenous ferumoxytol within 5 +/- 3 d or 200 mg of elemental oral iron daily for 21 d. The increase in hemoglobin at day 35, the primary efficacy end point, was 0.82 +/- 1.24 g/dl with ferumoxytol and 0.16 +/- 1.02 g/dl with oral iron (P < 0.0001). Among patients who were not receiving erythropoiesis-stimulating agents, hemoglobin increased 0.62 +/- 1.02 g/dl with ferumoxytol and 0.13 +/- 0.93 g/dl with oral iron. Among patients who were receiving erythropoiesis-stimulating agents, hemoglobin increased 1.16 +/- 1.49 g/dl with ferumoxytol and 0.19 +/- 1.14 g/dl with oral iron. Treatment-related adverse events occurred in 10.6% of patients who were treated with ferumoxytol and 24.0% of those who were treated with oral iron; none was serious. In summary, a regimen of two doses of 510 mg of intravenous ferumoxytol administered rapidly within 5 +/- 3 d was well tolerated and had the intended therapeutic effect. This regimen may offer a new, efficient option to treat iron deficiency anemia in patients with CKD.

Oxidative Stress and Inflammation in Chronic Kidney Disease: Role of Intravenous Iron and Vitamin D

Cardiovascular disease (CVD) is the leading cause of death among chronic kidney disease patients (CKD). The etiology of CVD in CKD is multifactorial and increasing evidence points to the important contribution of “nontraditional” risk factors including oxidative stress and inflammation. CKD is associated with a chronic imbalance of prooxidant and antioxidant factors that results in a state of chronic inflammation. Intravenous iron supplementation has been shown to induce oxidative stress and has been associated with lipid peroxidation and DNA damage. Conversely, treatment with vitamin D analogs has been associated with improved mortality in hemodialysis patients in 2 recent large cohort studies. These data suggest that vitamin D analogs may exert effects beyond their pharmacologic role in parathyroid hormone suppression. This article addresses the current data regarding the relative contributions of intravenous iron supplementation and vitamin D analog therapy on oxidative stress and inflammation in CKD patients.