INTRAVENOUS IMMUNOGLOBULIN TREATMENT IN CHRONIC INFLAMMATORY DEMYELINATING POLYNEUROPATHY - A DOUBLE-BLIND, PLACEBO-CONTROLLED, CROSS-OVER STUDY

Thirty patients with definite or probable chronic inflammatory demyeli nating polyradiculoneuropathy (CIDP) of chronic progressive (16 patien ts) or relapsing (14 patients) course were randomly assigned to receiv e intravenous immunoglobulin (IvIg) 0.4 g per kg body weight or a plac ebo treatment on 5 consecutive days in a double-blind, crossover trial . Neurological function was monitored by serial quantitative assessmen ts [neurological disability (NDS); clinical grade (CG) and grip streng th measurements] and by electrophysiological studies before and after each treatment period. Twenty-five patients completed both treatment p eriods. A comparison of the observed changes in clinical outcome measu res revealed statistically significant differences in favour of IvIg, with (mean+/-SD) improvements in NDS by 24.4+/-5.4 points (P < 0.002) in CG by 1+/-0.3 points (P < 0.001) in GS by +6.3+/-1.7 kg (P < 0.005) , whereas scores were unchanged or worse with placebo. A secondary two -group analysis of the first trial period included all 30 patients; 16 patients had been randomly assigned to IvIg and 14 to placebo treatme nts. Again significant differences in favour of IvIg were observed in all the clinical end-points: improvement in NDS was 35.6+/-25 points ( P < 0.0001), in CG it was 1.3+/-1.9 points (P < 0.002) and in GS +9.8/-7.7 kg (P < 0.001), whereas all scores worsened with placebo. Of the 30 patients, 19 (63%) improved with IvIg treatments; nine out of 16 p atients (56%) with chronic progressive CIDP, and 10 out of 14 patients (72%) with relapsing CIDP (differences were not statistically signifi cant). A placebo response was seen in five patients. Comparison of pai red electrophysiological measurements before and 4 weeks after IvIg tr eatments revealed statistically significant improvements in the summed motor conduction velocities (Sigma MCV; P < -0.0001) and in the summe d compound muscle action potentials (CMAP) evoked with proximal stimul ation (Sigma proximal CMAP, P < 0.03) of median, ulnar, peroneal and t ibial nerves. Eight of nine IvIg responders with chronic progressive C IDP improved gradually to normal function with a single 5 day course o f IvIg; in five of these, small doses of prednisone were prescribed du ring follow-up. In 10 IvIg responders with relapsing CIDP: improvement lasted a median 6 weeks (range 3-22 weeks) and was reproducible with open label treatments. All 10 patients have been maintained and stabil ized with IvIg pulse therapy of I g per kg body weight or less, given as a single infusion prior to the expected relapse: A beneficial respo nse to IvIg was found to be most likely in patients with acute relapse or with disease of one year or less. patients with predominantly sens ory signs did not improve.