Randomized, placebo-controlled trial of ferric carboxymaltose in restless legs syndrome patients with iron deficiency anemia

Objective: Intravenous ferric carboxymaltose (FCM) has been shown to be efficacious in treating restless legs syndrome (RLS) symptoms in non-anemic patients. The aim of this study was to evaluate the effectiveness of FCM in treating RLS symptoms in patients who also had an iron deficiency anemia (IDA). Methods: This is a randomized, double-blinded, placebo-controlled study. Subjects with RLS and IDA were enrolled. Subjects received an infusion of either 1500 mg FCM or placebo in Phase I. The primary outcomes were a change-from-baseline at week six on the International Restless Legs Syndrome Study Group scale (IRLS). Phase II of the study involved long-term (52 weeks) follow-up, for those who responded to treatment in the prior phase, with the potential for further treatment if symptoms returned. Results: We enrolled 29 RLS patients with IDA (15 FCM and 14 placebo). At week six post-infusion, FCM compared to placebo group showed significant improvement from baseline in IRLS score (−13.47 ± 7.38 vs. 1.36 ± 3.59). Among secondary outcome variables, quality of sleep showed significant improvement from baseline in the FCM group. 61% of subjects remained off RLS medications at the Phase II, week-52 endpoint. There were no serious adverse events observed in the study. Conclusion: The study showed significant efficacy and safety of FCM 1500 mg treatment both in the short term (6 weeks) and long term (52 weeks) in RLS patients with IDA.