Background

Regular immunoglobulin treatment maintains strength and prevents disability in CIDP. Discrimination between active disease, with optimum symptom control on treatment, and disease in remission not requiring treatment is essential for therapeutic decision making and clinical trial design.

Aims

To compare treatment cessation versus gradual dose reduction in assessment of disease activity (immunoglobulin dependence) in a cohort of stable CIDP patients on maintenance immunoglobulin treatment. An approach to restabilisation of immunoglobulin dependent individuals is also described.

Methods

Retrospective review of IVIg cessation or gradual reduction in 33 patients with stable CIDP on maintenance IVIg. Demographic, clinical and treatment data were collected; clinical monitoring data was recorded prospectively as part of routine clinical practice.

Results

21/33 patients (62.6%) were immunoglobulin dependent, (gradual dose reduction:11, cessation:10). Mean change in I-RODS (-15, S.D. 16) and MRC-SS (-4, S.D 4) were clinically and statistically meaningful (>75% exceeded MCID). Mean time to deterioration was 5.0 (S.D 4.6) months; shorter in cessation group (3.5 months) than gradual reduction group (8.8 months). All patients were restabilised to previous baseline (mean: 2.3, S.D 4.3 months); half within one week of retreatment.

12 patients (37.4%) remained stable without treatment for ≥2 years (remission). 50% were identified rapidly by cessation and 50% by gradual dose reduction requiring mean 4.8 (S.D 2.8) years follow up and costing £113,623 per person Ig spend. No predictors of disease activity were identified.

Interpretation

A treatment cessation trial with close clinical monitoring is an efficient, cost-effective, and safe approach to assessing disease activity in CIDP.

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