Effects of ferric carboxymaltose on markers of mineral and bone metabolism: A single-center prospective observational study of women with iron deficiency

Ferric Carboxymaltose (FCM)-Associated Hypophosphatemia (HPP): A Systematic Review

BACKGROUND

Since 2015, ferric carboxymaltose (FCM), an intravenous (IV) iron formulation used for treating iron deficiency anemia (IDA), has been associated with an increasing number of reported hypophosphatemia (HPP) cases. Information on HPP clinical manifestations and incidence has not been reviewed.

METHODS

We reviewed HPP-associated adverse events reported to the FDA, case reports, case series, observational databases, clinical trials, meta-analyses, and FDA-approved labels. Our analysis found that FCM-associated HPP is a clinically important adverse drug reaction (ADR). The most common clinical manifestations are general weakness, fatigue, bone pain, muscle pain, osteomalacia, and fractures. Information on rates of FCM-associated HPP was from a review of clinical trials, observational databases, systematic reviews, and meta-analyses.

RESULTS

Clinical trials comparing FCM with other IV iron preparations identified FCM-associated HPP rates between 50% and 92% versus 2% and 8% with other IV iron formulations. Meta-analyses and systematic reviews confirmed these numbers. FDA-approved FCM labels do not include details of available ADR information in case reports, case series, observational databases, randomized trials, and meta-analyses.

CONCLUSION

We conclude that although the FDA-approved FCM Prescribing Label was updated in 2023, more robust recommendations on FCM-associated HPP are needed to prevent negative outcomes including osteomalacia and fractures. For patient safety, FCM label should advise monitoring serum phosphate levels prior to initiating first doses and before subsequent doses for all patients. Given differences between the FDA-approved FCM label and data reviewed herein, clinicians must be educated about FCM-associated HPP, difficulties treating HPP cases, and should consider administering other IV iron formulations that have lower rates of HPP.

Diagnosis and treatment of iron deficiency in chronic heart failure : Position statement of the heart failure working group of the Austrian Society of Cardiology

Iron deficiency (ID) is a common comorbidity in heart failure (HF), affecting 55% of chronic and up to 80% of acute HF patients, regardless of ejection fraction (EF). An ID is associated with reduced quality of life, impaired exercise capacity (VO2 peak), higher hospitalization rate and lower survival rate. It is also an independent predictor of HF outcomes. This consensus statement critically reviews the diagnostic criteria for ID in HF and provides recommendations for their use. The efficacy and safety of intravenous iron supplements, including ferric carboxymaltose (FCM) and ferric derisomaltose (FDI), are analyzed highlighting the indications and potential adverse effects. Key clinical trials and guideline recommendations are summarized. In summary, the document addresses the diagnostics, treatment and monitoring of ID in HF.

Ferric carboxymaltose with or without phosphate substitution in iron deficiency or iron deficiency anemia before elective surgery - The DeFICIT trial

BACKGROUND

Iron deficiency anemia in the perioperative setting is treated predominantly with intravenous iron formulation, of which ferric carboxymaltose may induce hypophosphatemia by modulating fibroblast growth factor 23.

METHODS

In this single-center, prospective, randomized, double-blind trial, we consented 92 adult patients scheduled for elective major abdominal or thoracic surgery. These patients either had isolated iron deficiency (plasma ferritin <100 ng/mL or transferrin saturation < 20 %) or iron deficiency anemia (hemoglobin (Hb) 100-130 g/L with plasma ferritin <100 ng/mL or transferrin saturation < 20 %). Preoperatively, participants received a single preoperative intravenous dose of ferric carboxymaltose and were then randomly assigned to receive either phosphate or placebo, administered orally three times a day for 30 days corresponding to an 18 mmol dose of daily phosphate supplementation in the intervention group. The primary endpoint was the minimum serum phosphate concentration during follow-up visits. The key secondary efficacy endpoint was mean perioperative hemoglobin concentration of postoperative days 0, 2 and 4, assessing the non-inferiority of additional phosphate supplementation.

RESULTS

We randomly consented 46 patients in each group (mean ± SD age 56 ± 17 years, 57 % female). Minimal phosphate concentration was 0.49 ± 0.21 mmol/L in the treatment group and 0.42 ± 0.17 mmol/L in the placebo group (p = 0.12, two-sided p-value). Average mean hemoglobin was 110 ± 16 g/L in the treatment and 113 ± 13 g/L in the placebo group (p = 0.023, one-sided p-value for non-inferiority). Hypophosphatemia occurred in 32 patients (70 %) of the treatment group and in 39 patients (85 %) of the placebo group (odds ratio 0.15, 95 % CI from 0.02 to 0.77, p = 0.014). Secondary outcomes, such as rescue medication use, core muscle strength and MOCA test scores, did not differ between groups.

CONCLUSION

Co-administration of oral phosphate supplementation to ferric carboxymaltose cannot prevent hypophosphatemia. However, hypophosphatemia occurs in fewer patients. Phosphate co-administration did not impede the treatment of iron deficiency anemia with ferric carboxymaltose.

Hypophosphatemia related to intravenous iron therapy with ferric carboxymaltose: A case series

OBJECTIVES

This case series would like to highlight hypophosphatemia related to ferric carboxymaltose and its adverse clinical consequences.

BACKGROUND

Intravenous iron supplementation is a good alternative to oral iron replacement in iron deficiency anaemia due to its ability to correct iron deficit with minimal infusions without incurring the gastrointestinal side effects of oral iron replacement. Ferric carboxymaltose is one common formula for intravenous iron supplementation. However, an increasingly recognised adverse side-effect of intravenous ferric carboxymaltose is hypophosphatemia. There has been increasing reports and studies highlighting hypophosphatemia related to intra-venous iron therapy. Though initially thought to be transient and asymptomatic, recent studies have shown that persistent hypophosphatemia in iron therapy can result in debilitating disease including myopathy, fractures and osteomalacia.

METHODS

A retrospective analysis of all patients who had ferric carboxymaltose was performed.

RESULTS

We highlight 3 cases where hyposphatemia affected the clinical outcomes.

CONCLUSION

With the increased use of IV iron it is important to be aware of the high potential for hypophosphatemia secondary to ferric carboxymaltose.

What is wrong in doing good?

Hypophosphataemia is a common side-effect in patients with iron deficiency anaemia treated with ferric carboxymaltose, which is not a class effect of all intravenous (IV) iron formulations. The report by Chu et al. shows that moderate and severe hypophosphataemia is common and can even require IV supplementation of phosphate with unknown long-term consequences. Commentary on: Chu et al. Incidence and predictors of hypophosphataemia after ferric carboxymaltose use-a 3-year experience from a single institution in Singapore. Br J Haematol 2023;202:1199-1204.

High-Dose Intravenous Iron with Either Ferric Carboxymaltose or Ferric Derisomaltose: A Benefit-Risk Assessment

The intravenous iron formulations ferric carboxymaltose (FCM) and ferric derisomaltose (FDI) offer the possibility of administering a large amount of iron in one infusion. This results in faster correction of anemia and the formulations being better tolerated than oral iron formulations. This triad of logistic advantages, improved patient convenience, and fast correction of anemia explains the fact that intravenous iron formulations nowadays are frequently prescribed worldwide in the treatment of iron deficiency anemia. However, these formulations may result in hypophosphatemia by inducing a strong increase in active fibroblast growth factor-23 (FGF-23), a hormone that stimulates renal phosphate excretion. This effect is much more pronounced with FCM than with FDI, and therefore the risk of developing hypophosphatemia is remarkably higher with FCM than with FDI. Repeated use of FCM may result in severe osteomalacia, which is characterized by bone pain, Looser zones (pseudofractures), and low-trauma fractures. Intravenous iron preparations are also associated with other adverse effects, of which hypersensitivity reactions are the most important and are usually the result of a non-allergic complement activation on nanoparticles of free labile iron-Complement Activation-Related Pseudo-Allergy (CARPA). The risk on these hypersensitivity reactions can be reduced by choosing a slow infusion rate. Severe hypersensitivity reactions were reported in < 1% of prospective trials and the incidence seems comparable between the two formulations. A practical guideline has been developed based on baseline serum phosphate concentrations and predisposing risk factors, derived from published cases and risk factor analyses from trials, in order to establish the safe use of these formulations.

Risk Factors for and Effects of Persistent and Severe Hypophosphatemia Following Ferric Carboxymaltose

CONTEXT

Hypophosphatemia, osteomalacia, and fractures are complications of certain intravenous iron formulations.

OBJECTIVE

This study investigated risk factors for incident, severe, and persistent hypophosphatemia, and associated alterations in bone and mineral biomarkers following intravenous iron treatment.

METHODS

We analyzed data from the PHOSPHARE-IDA randomized clinical trials, comprising 245 patients aged 18 years or older with iron deficiency anemia at 30 outpatient clinics in the United States who received intravenous ferric carboxymaltose (FCM) or ferric derisomaltose (FDI). Outcome measures included serum phosphate, intact fibroblast growth factor-23 (iFGF23), 1,25-dihydroxyvitamin D (1,25(OH)2D), ionized calcium, parathyroid hormone (PTH), and alkaline phosphatase.

RESULTS

FCM was the only consistent risk factor for incident hypophosphatemia (< 2.0 mg/dL; odds ratio vs FDI: 38.37; 95% CI: 16.62, 88.56; P < 0.001). Only FCM-treated patients developed severe hypophosphatemia (< 1.0 mg/dL; 11.3%; 13/115) or persistent hypophosphatemia (< 2.0 mg/dL at study end; 40.0%; 46/115). More severe hypophosphatemia associated with significantly greater increases in iFGF23, PTH, and alkaline phosphatase, and more severe decreases in 1,25(OH)2D and ionized calcium (all P < 0.05). Patients with persistent vs resolved hypophosphatemia demonstrated significantly greater changes in iFGF23, PTH, 1,25(OH)2D, and N-terminal procollagen-1 peptide levels (all P < 0.01), but alkaline phosphatase increased similarly in both groups.

CONCLUSION

Treatment with FCM was the only consistent risk factor for hypophosphatemia. Patients who developed severe or persistent hypophosphatemia after FCM treatment manifested more severe derangements in bone and mineral metabolism. Changes in bone biomarkers continued beyond resolution of hypophosphatemia, suggesting ongoing effects on bone that may help explain the association of FCM with osteomalacia and fractures.

Hypophosphatemia after intravenous iron therapy: Comprehensive review of clinical findings and recommendations for management

Contemporary intravenous iron formulations allow administration of high doses of elemental iron and enable correction of total iron deficit in one or two infusions. An important but underappreciated complication of certain formulations is hypophosphatemia caused by increased secretion of the phosphaturic hormone, fibroblast growth factor 23 (FGF23). The pathophysiology of FGF23-induced hypophosphatemia due to certain intravenous iron formulations has been recently investigated in prospective clinical trials. To reach the correct diagnosis, clinicians must recognize the typical clinical manifestations of intravenous iron-induced hypophosphatemia and identify a specific pattern of biochemical changes (hyperphosphaturic hypophosphatemia triggered by high FGF23 that causes low 1,25 (OH)₂ vitamin D, hypocalcemia and secondary hyperparathyroidism). Physicians and patients should be aware of hypophosphatemia as a common complication of intravenous iron therapy and monitor serum phosphate concentrations in patients receiving repeated doses of specific intravenous iron formulations. Symptoms of hypophosphatemia are associated with severity and duration. Persistent hypophosphatemia can occur with iron therapy and can cause debilitating diseases including myopathy, osteomalacia and fractures. This review summarizes the current understanding of the iron-phosphate axis as well as complications of intravenous iron-induced hypophosphatemia.

HO-1: A new potential therapeutic target to combat osteoporosis

Heme oxygenase-1 (HO-1) exerts a protective effect against cell damage and induces the activity of many enzymes involved in the treatment of many human diseases, including osteoporosis. The increasing prevalence of osteoporosis and the limitations of the current treatments available led to a continuous occurrence of bone loss and osteoporotic fractures, highlighting the need of a better understanding of the mechanism and function of HO-1. Many factors cause osteoporosis, including lack of estrogen, aging, and iron overload, and they either cause the increase in inflammatory factors or the increase in reactive oxygen species to break bone reconstruction balance. Therefore, regulating the production of inflammatory factors and reactive oxygen species may become a strategy for the treatment of osteoporosis. Solid evidence showed that the overexpression of HO-1 compensates high oxidation levels by increasing intracellular antioxidant levels and reduces inflammation by suppressing pro-inflammatory factors. Some extracts can target HO-1 and ameliorate osteoporosis. However, no systematic report is available on therapies targeting HO-1 to combat osteoporosis. Therefore, this review summarizes the biological characteristics of HO-1, and the relationship between inflammatory response and reactive oxygen species production regulated by HO-1 and osteoporosis. The understanding of the role of HO-1 in osteoporosis may provide ideas for a potential clinical treatment and new drugs targeting HO-1.

[Hypophosphatemia following the administration of intravenous iron formulations: A case report and literature review]

Iron deficiency and iron-deficiency anemia are common medical conditions. Management of the etiology and iron supplementation are both necessary to treat this condition. Use of intravenous iron preparations is increasing due to its advantages over oral iron. Indeed, the total dose required can be provided in a single infusion, and it is more effective and increases hemoglobin levels more quickly than oral iron. Hypophosphatemia, sometimes severe, following intravenous iron administration, has been described in literature these past years, in particular with ferric carboxymaltose. We report here a case of severe hypophosphatemia with ferric carboxymaltose and carry out a literature review to determine the incidence of hypophosphatemia and to precise its clinical presentation, its pathophysiological mechanisms and its treatment. We found that hypophosphatemia is frequent with ferric carboxymaltose. Most of the time, there are no clinical manifestations, but cases of symptomatic osteomalacia have been described. Duration of hypophosphatemia is variable, from a few weeks to several months in case of prolonged administration. Hypophosphatemia owing to renal phosphate wasting is caused by an increase in intact fibroblast growth factor 23 (FGF-23) levels. However, the mechanism of ferric carboxymaltose- induced increase in intact FGF-23 is still unknown.

Hypophosphataemia, fibroblast growth factor 23 and third-generation intravenous iron compounds: a narrative review

Third-generation intravenous (i.v.) iron preparations are safe and efficacious and are increasingly used in the treatment of iron-deficiency anaemia. Hypophosphataemia is emerging as an established side-effect following the administration of certain compounds. Symptoms of hypophosphataemia can be masked by their similarity to those of iron-deficiency anaemia and both acute and chronic hypophosphataemia can be detrimental. Hypophosphataemia appears to be linked to imbalances in the metabolism of the phosphatonin fibroblast growth factor 23. In this narrative review, we discuss the possible pathophysiology behind this phenomenon, the studies comparing third-generation i.v. iron compounds, and the potential implications of the changes in fibroblast growth factor 23 and hypophosphataemia. We also present an algorithm of how to approach such patients requiring i.v. iron in anticipation of hypophosphataemia and how the impact related to it can be minimized.