Objective: To test the safety and efficacy of interferon beta-1a (IFN-beta) in treatment-resistant chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).
Background: 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.
Methods: 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.
Results: 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.
Conclusion: This trial shows that IFN-beta is safe but not efficacious in treatment-resistant CIDP.