Pilot Study: Randomized, Placebo-controlled Comparator Trial of IV vs Oral Iron Treatment of RLS With IDA. (IVOR-IDA)

The restless legs syndrome (RLS) (also known as Willis Ekbom Disease) occurs in about 1/3rd of patients with iron deficiency anemia (IDA). Treatment correcting the IDA is expected to also be effective for reducing or eliminating the RLS with IDA. Two accepted treatments for IDA (oral ferrous sulfate, intravenous ferumoxytol) will be compared for efficacy and speed to response for treatment of RLS occurring with IDA (RLS-IDA). In this study 70 RLS-IDA patients will be randomly assigned 35 each to oral or IV iron treatment using double-blind procedures. Primary outcome with be determined at 6 weeks of treatment with a follow-up at 12 months after treatment. Non-responders at 6 weeks after treatment may, if they qualify, have an open-label IV iron treatment and they will be followed with the same evaluations used after the first set of IV iron treatments.

Both oral and IV iron are considered standard treatments for IDA. These same treatments also reduce RLS symptoms. The treatment doses are those accepted for treatment of RLS and also appropriate for treatment for RLS-IDA. Choosing doses equivalent to those for the treatment of RLS without IDA will allow a comparison with that literature. The investigators will therefore use for oral iron ferrous sulfate 325mg taken twice a day matching the dose used in the study of oral iron treatment for RLS without anemia. For IV iron investigators will use ferumoxytol, provided by the sponsor, two doses of 510 mg spaced 2 to 7 days apart. This is the FDA approved dose for treatment of IDA with end stage renal disease.

The study is a randomized, comparative open label study to evaluate effect size and time course of treatment response for RLS-IDA over 6 weeks with a 46-week follow-up extension. Two medications and placebos will be used, as described above, with equal random assignment to both groups.