Very High Dose Immunoglobulin Treatment for Chronic Inflammatory Demyelinating Polyneuropathy: A Multicentre UK Study

ABSTRACT Background Immunoglobulin dosing is individualised in chronic inflammatory demyelinating polyneuropathy (CIDP). Methods We retrospectively compared differences in presentation/outcomes/side effects in subjects on very high dose immunoglobulin defined as ≥ 2 g/kg every 3 weeks (‘Group A’) and subjects on ≤ 1 g/kg every 3 weeks (‘Group B’), from 2 UK centres. Results One‐hundred and eight subjects with CIDP received immunoglobulins. Group A consisted of 12 subjects (11.1%). Mean dose was 2.63 g/kg every 3 weeks (SD: 0.71). Six subjects (50%) had typical CIDP, 3 (25%) had motor CIDP, and 3 (25%) had multifocal CIDP. Group B consisted of 40 subjects (37%) on a mean dose of 0.47 g/kg every 3 weeks (SD: 0.16). Compared to subjects from Group B, subjects from Group A had greater pre‐treatment disability ( p = 0.029), more common associated autoimmune disease ( p = 0.034), worse post‐treatment outcome ( p = 0.005) and a longer time to maximal improvement ( p = 0.041). No differences were found between the two groups for age/gender/weight/acuteness of presentation/side‐effects. Occurrence of any side‐effect ( p = 0.005), and of thromboembolic complication ( p = 0.022), were associated with presence of another autoimmune disease. Conclusions Very high dose immunoglobulin may be partially effective in a minority of subjects with CIDP. Subjects treated with very high dose immunoglobulin may have greater pre‐treatment disability, be more likely to have another autoimmune disease, have worse post‐treatment outcomes, and take longer to reach maximal improvement, than subjects on lower doses. Concurrent autoimmune disease may increase immunoglobulin‐induced thromboembolic risk. Earlier consideration of alternative therapies may be more appropriate than immunoglobulin dose escalation in subjects with suboptimal immunoglobulin response.