Randomized trial of interferon beta-1a in chronic inflammatory demyelinating polyradiculoneuropathy

To test the safety and efficacy of interferon beta-1a (IFN-beta) in treatment-resistant chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

Current treatment regimens leave 4% to 30% of patients with CIDP with moderate or severe disability. IFN-beta has been reported as beneficial in one treatment-resistant patient.

Ten consecutive treatment-resistant patients were randomized in a double-blind, crossover design to receive placebo or IFN-beta (3 MIU for 2 weeks and then 6 MIU for 10 weeks) subcutaneously three times weekly, followed by 4 weeks without treatment, and then the opposite treatment for 12 weeks. The primary outcome measure was "clinically important" improvement by specified amounts in any three of eight clinical measures: timed 10-m walk, Ambulation Index, expanded Medical Research Council sum score, nine-hole peg test time, Functional Independence Measure, Hammersmith Motor Ability, a new Guy's Neurological Disability Scale, and the EuroQoL quality-of-life scale. These and motor median nerve conduction studies were measured before and after 12 weeks of each treatment.

Clinically important improvement was observed in one patient while taking IFN-beta and two patients while taking placebo. There was no significant difference between IFN-beta and placebo in the change in any of the individual clinical or neurophysiological measures between the beginning and end of treatment. There were no serious adverse events.

This trial shows that IFN-beta is safe but not efficacious in treatment-resistant CIDP.