P658 A pooled analysis of serum phosphate measurements and transient decreased phosphate levels in 45 interventional trials with ferric carboxymaltose

Abstract

Abstract Background ECCO guidelines acknowledge the limitations of oral iron for iron deficiency anaemia in IBD and recommend first-line IV iron in patients with active disease. Ferric carboxymaltose (FCM) is approved for iron deficiency when oral iron is ineffective/inappropriate. FCM has shown benefit in RCTs, and as with other IV irons, is known to cause a transient decrease in serum phosphate (PO4), which in most cases is asymptomatic. The aim of this pooled analysis was to characterise the frequency, duration, risk factors, and clinical signs of hypophosphataemia (HP) across 45 interventional trials with FCM. Methods 15,080 subjects were included (FCM n = 8,245; controls n = 6,835). 12,683 had post-baseline serum PO4 measurements (FCM n = 6,879), which were pooled by time-point, clinical characteristics, dose, and iron parameters. Serum PO4 thresholds were: 2.5–<4.5 mg/dl (normal), 2.0–<2.5 mg/dl (mild decrease), 1–<2.0 mg/dl (moderate), and <1 mg/dl (severe). Logistic regression analysis was used to identify predictors of HP. MedDRA terms were interrogated for reported and potential clinical signs of HP. Results 2,760 FCM subjects (40.1%) with normal PO4 at baseline developed HP (PO4 <2.5 mg/dl) on study. PO4 levels normalised in 1,705 subjects (61.8%); mean time to normalisation (±SD) was 40.7 days (±35.31). PO4 normalisation during follow-up did not occur in 177 subjects (0.06%). Independent risk factors for moderate/severe HP within 12 weeks of treatment included treatment setting (gastroenterology or neurology vs. women’s health), lower baseline ferritin level, maximum single-dose, advanced age, lower weight at baseline (all p < 0.0001), multiple doses vs. single dose (p = 0.0003), and higher cumulative dose (p = 0.0005). ‘Hypophosphataemia’ as a MedDRA term was approximately 10-fold more frequent with FCM than controls (2.2% vs. 0.2% with other IV irons). Potential clinical signs of HP were not more frequent with FCM vs. controls (Table) and were not associated with nadir levels of serum PO4. 4 of 49 FCM subjects (8.2%) who had nadir PO4 below 1 mg/dl had a potential clinical sign of HP, vs. 126/1,569 (8.0%) with 1–<2.0 mg/dl, 113/1,229 (9.2%) with 2.0–<2.5 mg/dl and 411/4,032 (10.2%) with ≥2.5 mg/dl. Among subjects with PO4 <2.5 mg/dl, serious cardiac disorders classified as potentially related to HP occurred in 14 FCM subjects (0.5%), 1 (0.7%) other IV iron, and 2 (4.4%) oral iron. Conclusion HP is recognised as a common adverse drug reaction with FCM as with several other IV iron preparations. This analysis shows that the transient decreases in PO4 levels were more frequent in patients receiving multiple and/or large doses of FCM but were not associated with an increased rate of potential signs/symptoms of HP.