Hypophosphatemia events more frequent with ferric carboxymaltose vs ferric derisomaltose

Ferric carboxymaltose (FCM) is as good as ferric derisomaltose (FDI) in the treatment of iron-deficiency anaemia, although FCM leads to a higher frequency of hypophosphatemia, according to data from the PHOSPHARE-IBD study.

PHOSPHARE-IBD included 156 adult patients with inflammatory bowel disease (IBD) and iron deficiency anaemia from 20 outpatient hospital clinics across Europe (Austria, Denmark, Germany, Sweden, UK). They were randomized to receive FCM or FDI at baseline and at day 35 using identical haemoglobin- and weight-based dosing regimens.

The primary outcome was the incidence of hypophosphatemia (defined as serum phosphate <2.0 mg/dL) at any time from baseline to day 35 in the safety analysis set (all patients who received ≥1 dose of study drug). Researchers also measured the markers of mineral and bone homeostasis, as well as patient-reported fatigue scores.

Of the patients, 97 (mean age 42.1 years, 52.6 percent female) were treated and included in the analysis: 48 patients in the FDI group and 49 patients in the FCM group. The population had a higher percentage of patients with ulcerative colitis (UC) than Crohn’s disease (CD), and the proportion of UC was higher in the FDI group. Other patient characteristics were well balanced between the treatment groups. The mean Hb at baseline was 105 g/L.

Hypophosphatemia occurred with significantly greater frequency among FCM- than FDI-treated patients (51.0 percent vs 8.3 percent; adjusted risk difference, −42.8 percent, 95 percent confidence interval [CI], –57.1 to –24.6; p<0.0001). Both iron formulations led to the correction of iron-deficiency anaemia.

Moreover, while patient-reported fatigue scores improved in both treatment groups, the improvement occurred more slowly and to a lesser extent with FCM than with FDI. Slower improvement in fatigue was associated with a greater decrease in phosphate concentration.