Intravenous immunoglobulin for chronic inflammatory demyelinating polyradiculoneuropathy.

BACKGROUND: Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) causes progressive or relapsing weakness and numbness of the limbs, developing over at least two months. Uncontrolled studies suggest that intravenous immunoglobulin (IVIg) helps. This review was first published in 2002 and has since been updated, most recently in 2013.
OBJECTIVES: To review systematically the evidence from randomised controlled trials (RCTs) concerning the efficacy and safety of IVIg in CIDP. SEARCH
METHODS: On 4 December 2012, we searched the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL (2012, issue 11 in the Cochrane Library), MEDLINE and EMBASE to December 2012 and ISI from January 1985 to May 2008. We searched for ongoing trials through two metaRegistries (World Health Organization International Clinical Trials Registry Platform Search Portal and Current Controlled Trials). SELECTION CRITERIA: We selected RCTs testing any dose of IVIg versus placebo, plasma exchange or corticosteroids in definite or probable CIDP. DATA COLLECTION AND ANALYSIS: Two authors reviewed literature searches to identify potentially relevant RCTs, scored their quality and extracted data independently. We contacted authors for additional information. MAIN
RESULTS: We considered eight RCTs, including 332 participants, to be eligible for inclusion in the review. These trials were homogeneous and the overall risk of bias low. Five studies, in a total of 235 participants compared IVIg against placebo. One trial with 20 participants compared IVIg with plasma exchange, one trial compared IVIg with prednisolone in 32 participants, and one trial, newly included at this update, compared IVIg with intravenous methylprednisolone in 46 participants.A significantly higher proportion of participants improved in disability within one month after IVIg treatment as compared with placebo (risk ratio (RR) 2.40, 95% confidence interval (CI) 1.72 to 3.36; number needed to treat for an additional beneficial outcome 3.03 (95% CI 2.33 to 4.55), high quality evidence). Whether all these improvements are equally clinically relevant cannot be deduced from this analysis because each trial used different disability scales and definitions of significant improvement. In three trials, including 84 participants, the disability score could be transformed to the modified Rankin score, on which improvement of one point after IVIg treatment compared to placebo was barely significant (RR 2.40, 95% CI 0.98 to 5.83) (moderate quality evidence). Only one placebo-controlled study included in this review had a long-term follow-up. The results of this study suggest that IVIg improves disability more than placebo over 24 and 48 weeks.The mean disability score revealed no significant difference between IVIg and plasma exchange at six weeks (moderate quality evidence). There was no significant difference in improvement in disability on prednisolone compared with IVIg after two or six weeks, or on methylprednisolone compared to IVIg after two weeks or six months (moderate quality evidence).There were no statistically significant differences in frequencies of side effects between the three types of treatment for which data were available (IVg versus placebo or steroids). (moderate or high quality evidence) Mild and transient adverse events were found in 49% of participants treated with IVIg, while serious adverse events were found in six per cent. AUTHORS'
CONCLUSIONS: The evidence from RCTs shows that IVIg improves disability for at least two to six weeks compared with placebo, with an NNTB of three. During this period it has similar efficacy to plasma exchange, oral prednisolone and intravenous methylprednisolone. In one large trial, the benefit of IVIg persisted for 24 and possibly 48 weeks. Further research is needed to compare the long-term benefits as well as side effects of IVIg with other treatments.