PLASMA-EXCHANGE THERAPY IN CHRONIC INFLAMMATORY DEMYELINATING POLYNEUROPATHY - A DOUBLE-BLIND, SHAM-CONTROLLED, CROSS-OVER STUDY

Eighteen patients with definite, untreated chronic inflammatory demyel inating polyradiculoneuropathy (CIDP) of chronic progressive (nine pat ients) or relapsing course (nine patients) were randomized prospective ly, to receive 10 plasma-exchange (PE) or sham plasma-exchange (SPE) t reatments over 4 weeks in a double-blind trial. After a wash-out perio d of 5 weeks or when they returned to baseline scores, patients were c rossed over to the alternate treatments. Neurological function was ass essed serially using a quantitative neurological disability score (NDS ), a functional clinical grade (CG) and grip strength (GS) measurement s. Electrophysiological studies were done at the beginning and end of each treatment. A primary 'intention to treat' analysis showed signifi cant improvement with PE in all clinical outcome measures: NDS by 38 p oints, P < 0.001; CG by 1.6 points, P < 0.001; GS by +13 kg, P < 0.003 and in selected electrophysiological measurements, Sigma proximal CMA P, P < 0.01; Sigma motor conduction velocities, P < 0.006; Sigma dista l motor latencies, P < 0.01. Fifteen patients completed the trial and of those, 12 patients (80%) improved substantially with PE; i.e. Jive out of seven patients with chronic progressive course and seven out of eight patients with relapsing CIDP improved. There were three drop-ou ts: one patient lost venous access; one patient suffered a stroke and one patient left the trial to receive open treatment elsewhere. The im provement in motor functions correlated with the electrophysiological data, i.e. with improved motor conduction velocities and reversal of c onduction block. Eight of 12 PE responders (66%) relapsed within 7-14 days after stopping PE. All improved with subsequent open label PE; al l but two patients required long-term immunosuppressive drug therapy f or stabilisation. The PE non-responders improved with prednisone. We c onclude that PE is a very effective adjuvant therapy for CIDP of both chronic progressive and relapsing course; concurrent immunosuppressive drug treatment is required. Exchange treatments should be given two t o three times per week until improvement is established; the treatment frequency should then be tapered over several months.