Follow-up nerve conductions studies in CIDP after treatment with IGIV-C: comparison of patients with and without subsequent relapse

Introduction: Electrodiagnostic studies (EDX) are not performed routinely before treatment suspension in CIDP, and no data exist regarding their value in predicting clinical relapse. Methods: Serial EDX (baseline and after IGIV-C therapy) were analyzed from subjects in the ICE clinical trial who responded to IGIV-C treatment and were subsequently re-randomized to placebo in an extension phase. Comparisons were made between subjects who relapsed and those who did not. Results: A total of 55% (6/11) of the Relapse group had an increase in total number of demyelinating findings (DF) versus 8% (1/13) in the No Relapse group (P = 0.023). In the Relapse group, 100% had >= 1 new DF and 73% (8/11) had >= 4 new DF versus 60% (8/13) and 8% (1/13), respectively, in the No Relapse group. Conclusions: An increased total number of DF or the occurrence of >= 4 new DF may indicate a higher risk of clinical relapse after treatment cessation in IGIV-C-responsive patients.