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

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.

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.

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.

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.