Clinical efficacy and safety of intravenous ferric carboxymaltose for treatment of restless legs syndrome: a multicenter, randomized, placebo-controlled clinical trial.

STUDY OBJECTIVES: Iron therapy is associated with improvements in restless legs syndrome (RLS). This multicenter, randomized, double-blind study evaluated the effect of intravenous ferric carboxymaltose (FCM) on RLS. METHODS: A total of 209 adult patients with a baseline International RLS (IRLS) score ≥ 15 were randomized (1:1) to FCM (750 mg/15 mL) or placebo on study days 0 and 5. Ongoing RLS medication was tapered starting on Day 5, with the goal of discontinuing treatment or achieving the lowest effective dose. Co-primary efficacy endpoints were changed from baseline in IRLS total score and the proportion of patients rated as much/very much improved on the Clinical Global Impression (CGI)-investigator (CGI-I) scale at day 42 in the "As-Treated" population. RESULTS: The "As-Treated" population comprised 107 FCM and 101 placebo recipients; 88 (82.2%) and 68 (67.3%), respectively, completed the day 42 assessment. The IRLS score reduction was significantly greater with FCM versus placebo: least-squares mean (95% confidence interval [CI]) -8.0 (-9.5, -6.4) versus -4.8 (-6.4, -3.1); p = .0036. No significant difference was observed in the proportion of FCM (35.5%) and placebo (28.7%) recipients with a CGI-I response (odds ratio 1.37 [95% CI: 0.76, 2.47]; p = .2987). Fewer patients treated with FCM (32.7%) than placebo (59.4%) received RLS interventions between day 5 and study end (p = .0002). FCM was well tolerated. CONCLUSIONS: The IRLS score improved with intravenous FCM versus placebo, although the combination of both co-primary endpoints was not met. Potential methodological problems in the study design are discussed.

Safety, pharmacokinetics, and pharmacodynamics of intravenous ferric carboxymaltose in children with iron deficiency anemia.

BACKGROUND: Iron deficiency is the primary cause of anemia in children. Intravenous (IV) iron formulations circumvent malabsorption and rapidly restore hemoglobin. METHODS: This Phase 2, non-randomized, multicenter study characterized the safety profile and determined appropriate dosing of ferric carboxymaltose (FCM) in children with iron deficiency anemia. Patients aged 1-17 years with hemoglobin <11 g/dL and transferrin saturation <20% received single IV doses of undiluted FCM 7.5 mg/kg (n = 16) or 15 mg/kg (n = 19). RESULTS: The most common drug-related treatment-emergent adverse event was urticaria (in three recipients of FCM 15 mg/kg). Systemic exposure to iron increased in a dose-proportional manner with approximate doubling of mean baseline-corrected maximum serum iron concentration (157 µg/mL with FCM 7.5 mg/kg; and 310 µg/mL with FCM 15 mg/kg) and area under the serum concentration-time curve (1901 and 4851 h·µg/mL, respectively). Baseline hemoglobin was 9.2 and 9.5 g/dL in the FCM 7.5 and 15 mg/kg groups, respectively, with mean maximum changes in hemoglobin of 2.2 and 3.0 g/dL, respectively. CONCLUSIONS: In conclusion, FCM was well tolerated by pediatric patients. Improvements in hemoglobin were greater with the higher dose, supporting use of the FCM 15 mg/kg dose in pediatric patients (Clinicaltrials.gov NCT02410213). IMPACT: This study provided information on the pharmacokinetics and safety of intravenous ferric carboxymaltose for treatment of iron deficiency anemia in children and adolescents. In children aged 1-17 years with iron deficiency anemia, single intravenous doses of ferric carboxymaltose 7.5 or 15 mg/kg increased systemic exposure to iron in a dose-proportional manner, with clinically meaningful increases in hemoglobin. The most common drug-related treatment-emergent adverse event was urticaria. The findings suggest that iron deficiency anemia in children can be corrected with a single intravenous dose of ferric carboxymaltose and support use of a 15 mg/kg dose.