Background: Efgartigimod, a human immunoglobulin (Ig)G1 antibody Fc fragment, blocks the neonatal Fc receptor, reducing IgGs involved in chronic inflammatory demyelinating polyneuropathy (CIDP), a rare, progressive, immune-mediated disease that can lead to irreversible disability. The multi-stage, double-blinded, placebo-controlled ADHERE (NCT04281472) trial assessed efgartigimod PH20 SC in participants with CIDP. Methods: Participants with active CIDP received open-label, weekly efgartigimod PH20 SC 1000 mg during ≤12-week run-in (stage-A). Responders were randomized (1:1) to weekly efgartigimod or placebo for ≤48 weeks (stage-B). This posthoc analysis evaluated changes from run-in baseline (study enrollment) to stage-B last assessment and items of the Inflammatory Rasch-built Overall Disability Scale (I-RODS). Results: Of 322 participants who entered stage-A, 221 were randomized and treated in stage-B, and 191/221 had data for run-in baseline and post–stage-B timepoints. Mean (SE) I-RODS change at stage-B last assessment vs run-in baseline was 5.7 (1.88) and -4.9 (1.82) in participants randomized to efgartigimod and placebo, respectively. 37/97 (38.1%) and 24/92 (26.1%) participants randomized to efgartigimod and placebo, respectively, experienced ≥4-point improvements in I-RODS score. Efgartigimod-treated participants improved ≥1 point in I-RODS items of clinical interest. Conclusions: Participants who received efgartigimod in stage-B experienced improvements in I-RODS score from study enrollment to stage-B last assessment.