Hypophosphatemia after High Dosage Iron Substitution with Ferric Carboxymaltose (FCM) and Iron Isomaltoside (IM) – the Randomised Controlled Home Afers 1 Trial

In iron deficiency anaemia patients, intravenous administration of either ferric carboxymaltose (FCM) or iron isomaltoside (IM) both allow high dosage iron substitution within a single outpatient visit. In contrast, other iron compounds require repetitive, low dosage infusions. Recently, FCM was reported to frequently induce acute, reversible hypophosphatemia. It remains enigmatic whether these hypophosphataemic effects of FCM are substance-specific, or whether they generally occur after high dosage iron substitution. A direct comparison of phosphorus regulation after high dosage iron substitution with either FCM or IM is clinically important, as hypophosphatemia after FCM has anecdotally been associated with osteomalacia and bone fractures. In the HOMe AFers 1 (HOMburg evaluations on application of Ferrum study 1) trial, we recruited normophosphatemic women with gynaecological bleeding and subsequent iron deficiency anaemia, in whom we assessed the longitudinal biochemical response over 28 days to a single intravenous injection of equivalent doses of randomly-assigned FCM and IM (1000 mg). The primary study hypothesis was that the incidence of hypophosphatemia - defined as plasma phosphorus At the time point of the interim analysis, 26 patients have been recruited. One patient withdrew her acceptance to participate after day 1, leaving 25 patients for our per protocol interim analysis. Baseline plasma phosphorus did not differ significantly between FMC (3.3 ± 0.4 mg/dl) and IM (3.6 ± 0.6 mg/dl; p = 0.135). Analysis on the primary endpoint demonstrated that significantly more women developed hypophosphatemia In conclusion, while both FCM and IM provide efficient iron substitution in iron deficiency anaemia, FCM induced a substantially higher incidence of hypophosphatemia. Disclosures Emrich: Pharmacosmos: Consultancy, Honoraria, Research Funding. Stilgenbauer: Mundipharma: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding; Pharmcyclics: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding; Sanofi: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding; Genentech: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding; Genzyme: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding; Boehringer-Ingelheim: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding; Hoffmann La-Roche: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding; GSK: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding. Brandenburg: Pharmacosmos: Consultancy, Honoraria, Research Funding; Vifor: Consultancy, Honoraria. Heine: Pharmacosmos: Consultancy, Honoraria, Research Funding.