Intravenous immunoglobulin overtreatment in chronic inflammatory demyelinating polyneuropathy (CIDP)

INTERVENTION: Pharmaceutical Form: Solution for infusion Pharmaceutical form of the placebo: Solution for infusion Route of administration of the placebo: Intravenous use Trade Name: Sodium Chloride 0.9% Product Name: Sodium Chloride 0.9% Product Code: RVG 51680 Pharmaceutical Form: Solution for infusion Pharmaceutical Form: Solution for infusion CONDITION: Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) Therapeutic area: Diseases [C] ‐ Nervous System Diseases [C10] PRIMARY OUTCOME: Main Objective: The primary objective is to determine whether subjects with CIDP are overtreated with maintenance IVIg treatment and to reduce overtreatment‐associated subjects’ burden and health care costs. Primary end point(s): For the primary outcome we will use the Rasch‐Overall Disability Scale (R‐ODS), a patient self‐report linearly weighted scale that measures activity and social participation limitations. Secondary Objective: Secondary objective is to search for possible explanatory factors of ongoing need of IVIg treatment. Timepoint(s) of evaluation of this end point: At 24 weeks or at a predefined early end‐point. Participants will reach an early endpoint if they deteriorate on the R‐ODS by more than 0.652 logits during follow‐up. SECONDARY OUTCOME: Secondary end point(s): 1) The proportion of subjects remaining stable on their individual R‐ODS score and completing the follow‐period. An individual subject will be considered stable if the difference between his or her baseline and endpoint R‐ODS scores is less than 0.652 logits. ; 2) Muscle strength using the Medical Research Council (MRC) sum score of 12 predefined muscle groups (range 0 to 60, including shoulder abduction, elbow flexion, wrist extension, hip flexion, knee extension and foot dorsiflexion). ; 3) Grip strength, measured in kPa by a Martin‐Vigorimeter. ; 4) Sensory impairment using the modified INCAT Sensory Sum Score (INCAT–SS, range 0‐20). ; 5) Subject’s perception of clinical deterioration on a 5‐point Likert scale. ; 6) Disase‐non‐specific disability using the AMC Linear Disability Scale (ALDS, range 0 [dead] to 100 [fully able]). ; 7) Quality of life using Short Form‐36 (SF‐36). ; 8) Pain using the Pain‐Intensity Numerical Rating Scale (PI‐NRS, a 11‐point scale). ; 9) Fatigue using a 7‐item linear modified Rasch‐built fatigue scale. ; 10) Costs of health care use, costs of production loss, and out‐of‐pocket expenses. ; 11) Difference between serum IgG levels before and after last IVIg infusion prior to first study treatment. ; Timepoint(s) of evaluation of this end point: At 24 weeks or at a predefined early end‐point. Participants will reach an early endpoint if they deteriorate on the R‐ODS by more than 0.652 logits during follow‐up. INCLUSION CRITERIA: 1) Probable or definite CIDP according to the EFNS/PNS criteria 20103 2) Stable disease for 6 months (e.g. no progression of disease in last 6 months) 3) IVIg treatment for at least 6 months 4) IVIg infusion interval of 2 to 6 weeks. 5) Age > 18 years Are the trial subjects under 18? no Number of subjects for this age range: F.1.2 Adults (18‐64 years) yes F.1.2.1 Number of subjects for this age range 50 F.1.3 Elderly (>=65 years) yes F.1.3.1 Number of subjects for this age range 10