Iron isomaltoside, with or without dopamine medicine, for restless legs syndrome

Who can take part

• RLS diagnosed according to the current IRLSSG criteria Essential diagnostic criteria (all must be met): a) An urge to move the legs usually but not always accompanied by, or felt to be caused by, uncomfortable and unpleasant sensation in the legs. b) The urge to move the legs and any accompanying unpleasant sensations begin or worsen during periods of rest or inactivity such as lying down or sitting c) The urge to move the legs and any accompanying unpleasant sensations are partially or totally relieved by movement, such as walking or stretching, at least as long as the activity continues. d) The urge to move the legs and any accompanying unpleasant sensations during rest or inactivity only occur or are worse in the evening or night than during the day. d) The occurence of the above features is not solely accounted for as symptoms primary to another medical or a behavioral condition (e.g. myalgia, venous stasis, leg edema, arthritis, leg cramps, positional discomfort, habitual foot tapping)
• Female and male participants aged ≥ 18 years
• Negative urine/serum pregnancy test in women of childbearing potential (WOCBP). WOCBP who are sexually active, agree to use highly effective means of contraception during the study and for at least 1 month post-study treatment. Allowed are accepted and effective hormonal/non-hormonal methods of contraception and sexual abstinence or vasectomised partners (> 3 months previously). Vasectomy has to be confirmed by two negative semen analyses
• IRLS score >=15
• For the DA group, DA dosage not exceeding the max recommended dosage for RLS (PMID 27448465): Pramipexole 0.75 mg/day, Ropinirole 4mg/day, Rotigotine 3 mg/day
• Written, signed and dated informed consent

Who cannot take part

• Iron substitution, erythropoietin therapy or blood transfusion in the previous 6 months
• Phosphate levels below the lower limit normal before study drug initiation
• Contraindications for performing a MRI (for example claustrophobia, pacemakers, metal implants)
• Malignancies
• Moderate or severe heart failure (NYHA III - IV)
• Ferritin > 300 mg/dL or Transferrin Saturation over 45%
• Known Hypersensitivity to the active substance or any of its excipients (Sodium hydroxide/Hydrochloric acid
• Dialysis-dependent renal failure (eGFR<20mL/min/1.73m² calculated by MDRD formula)
• Secondary RLS
• Pregnancy/brestfeeding
• Known thalassaemia minima/minor, hemochromatosis, polycythemia vera, hemolytic anemia
• Body weight < 50 kg
• Sporadic RLS