Many Clinically Stable CIDP Patients Can Safely Stop IVIG Maintenance Treatment

While intravenous immune globulin (IVIG) therapy is efficacious for patients with chronic inflammatory demyelinating polyneuropathy (CIDP), the lack of biomarkers for disease activity makes the need for ongoing treatment difficult to assess.

To determine whether IVIG withdrawal is noninferior to continuing IVIG treatment, a team of Dutch investigators performed a randomized, double-blind, IVIG-controlled noninferiority trial in 60 clinically stable adults with CIDP on IVIG maintenance therapy for at least six months. Patients either continued on IVIG treatment or received IVIG withdrawal as investigational treatment. The primary outcome measure was the mean change in logit scores from baseline to week 24 follow-up on the patient-reported Inflammatory Rasch-Overall Disability Scale (iRODS). The noninferiority margin was predefined as between-group difference in mean change scores of -0.65. Patients who deteriorated could reach a relapse endpoint according to predefined criteria; those in the IVIG withdrawal group entered a restabilization phase. All those in the withdrawal group who remained stable were included in a 52-week open-label extension phase.

The between-group difference in mean change iRODS scores was -0.47, with a 95 percent confidence interval from -1.24 to 0.31; noninferiority of IVIG withdrawal therefore could not be established. However, 41 percent of patients randomized to IVIG withdrawal remained stable for 24 weeks, compared to 58 percent in the IVIG continuation group. Of those in the IVIG withdrawal group, 28 percent remained stable at the end of the extension phase. Of those who relapsed and entered the restabilization phase, 94 percent restabilized within 12 weeks.

While acknowledging that it remains inconclusive whether IVIG withdrawal is noninferior compared to continuing treatment, the investigators noted that “a considerable proportion of patients could stop treatment, and almost all patients who relapsed were restabilized quickly.” They concluded that these findings “suggest that withdrawal attempts are safe and should be performed regularly in clinically stable patients.” In addition, they noted that an unexpectedly high proportion of IVIG-treated patients experienced a relapse endpoint, emphasizing the need for more objective measures for disease activity in future trials.