Intramuscular interferon beta-1a in chronic inflammatory demyelinating polyradiculoneuropathy.
OBJECTIVE
Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) shares immunologic features with multiple sclerosis (MS). Because IM interferon beta-1a (IM IFNbeta-1a) is an effective and safe treatment for MS, we conducted a dose-ranging efficacy study of IFNbeta-1a in patients with CIDP.


METHODS
Adults with IV immunoglobulin (IVIg)-dependent CIDP (n = 67) were enrolled in this 32-week double-blind trial and randomized to IM IFNbeta-1a. Patients received 30 microg once weekly plus placebo (n = 12), IM IFNbeta-1a 60 microg once weekly plus placebo (n = 11), IM IFNbeta-1a 30 microg twice weekly (n = 11), IM IFNbeta-1a 60 microg twice weekly (n = 11), or placebo twice weekly (n = 22). Participants were maintained on IVIg through week 16, when IVIg was discontinued. Patients who worsened were restarted on IVIg. The primary outcome was total IVIg dose (g/kg) administered from week 16 to 32.


RESULTS
There was no difference in total IVIg dose administered after week 16 for patients treated with IFNbeta-1a (1.20 g/kg) compared with placebo (1.34 g/kg; p = 0.75). However, exploratory analyses suggested IFNbeta-1a significantly reduced total dose of IVIg compared with placebo for participants who required either high-dose IVIg (>0.95 g/kg per month) or had greater weakness at baseline (Medical Research Council sum score <51). Adverse events included flu-like symptoms, headache, and fatigue in the IFNbeta-1a groups.


CONCLUSIONS
Interferon beta-1a (IFNbeta-1a) therapy did not provide significant benefit over IV immunoglobulin (IVIg) therapy alone for patients with chronic inflammatory demyelinating polyradiculoneuropathy. However, IFNbeta-1a might be beneficial for patients with more severe disability or those needing high doses of IVIg.


METHODS
This study was designed to provide Class I evidence for the safety and efficacy of IM IFNbeta-1a in the treatment of CIDP but has been subsequently classified as Class II due to a >20% patient dropout rate. Thus, this randomized, controlled clinical trial provides Class II evidence of no effect on primary and secondary endpoints of 4 dosage regimens of IM IFNbeta-1a added to IVIg in persons with CIDP.
Hughes
R A C
RA
Department of Neurology, St. Elizabeth's Medical Center, 736 Cambridge Street, Boston, MA 02135, USA.
Gorson
K C
KC
Cros
D
D
Griffin
J
J
Pollard
J
J
Vallat
J-M
JM
Maurer
S L
SL
Riester
K
K
Davar
G
G
Dawson
K
K
Sandrock
A
A
D000276:Adjuvants, Immunologic / Q000008:administration & dosage / Q000009:adverse effects; D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005221:Fatigue / Q000139:chemically induced; D005260:Female; D006261:Headache / Q000139:chemically induced; D006801:Humans; D007273:Injections, Intramuscular; D000068556:Interferon beta-1a; D016899:Interferon-beta / Q000008:administration & dosage* / Q000009:adverse effects*; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D020277:Polyradiculoneuropathy, Chronic Inflammatory Demyelinating / Q000188:drug therapy*; D016016:Proportional Hazards Models; D012044:Regression Analysis; D016896:Treatment Outcome
D000276:Adjuvants, Immunologic; D016899:Interferon-beta; D000068556:Interferon beta-1a