What are the first‑line treatment options for chronic inflammatory demyelinating polyneuropathy (CIDP) and how should they be administered?

First-Line Treatment for CIDP

For chronic inflammatory demyelinating polyneuropathy (CIDP), initiate treatment with either intravenous immunoglobulin (IVIg) or corticosteroids as first-line therapy, with plasma exchange reserved as an alternative if these prove ineffective. 1

Treatment Algorithm

Initial Treatment Selection

The 2021 European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) guideline provides strong recommendations for first-line therapy 1:

Preferred First-Line Options:

• IVIg: Standard dosing typically 2 g/kg divided over 2-5 days for induction 2, 3
• Corticosteroids: Either daily oral therapy or pulse dosing (both induction and maintenance) 3, 1

When to Choose IVIg Over Corticosteroids:

• Motor-predominant CIDP variants (Good Practice Point recommendation) 1
• Patients where corticosteroid side effects are particularly concerning
• Rapid onset of action needed

When to Choose Corticosteroids:

• Cost considerations (significantly less expensive than IVIg)
• Effective for both induction and maintenance phases 3
• Patient preference for oral medication

Second-Line Treatment

If IVIg and corticosteroids are ineffective, plasma exchange is strongly recommended 1. This represents escalation therapy rather than treatment failure, as approximately 40% of patients may not show initial improvement with standard first-line treatments 4.

Administration Protocols

IVIg Dosing

• Induction: 2 g/kg total dose divided over 2-5 consecutive days 2
• Maintenance: Repeat infusions at intervals determined by clinical response, typically every 3-4 weeks 1
• Subcutaneous immunoglobulin: Alternative maintenance option 1, 5

Corticosteroid Regimens

• Daily oral: Prednisone starting at 0.75-1 mg/kg/day
• Pulse therapy: High-dose intravenous methylprednisolone (e.g., 1000 mg for 3-5 days) 3
• Both approaches effective for induction and maintenance 3

Plasma Exchange

• Typically 5-6 exchanges over 2 weeks
• Reserved for refractory cases 1

Maintenance Strategy

After achieving clinical improvement:

1. Continue effective first-line agent (IVIg, subcutaneous immunoglobulin, or corticosteroids) 1

2. If high maintenance doses required, consider:

   • Combination of first-line treatments
   • Adding immunosuppressant/immunomodulatory drugs as steroid-sparing agents 1

3. Monitor for treatment response and adjust dosing intervals based on clinical stability 6

Critical Considerations

Treatment-Related Fluctuations (TRFs):

• Occur in 6-10% of patients within 2 months of initial improvement 4
• Repeat full course of IVIg or plasma exchange if TRFs occur 4
• Three or more TRFs or deterioration ≥8 weeks after onset suggests acute-onset CIDP requiring long-term maintenance 4

Variant-Specific Approaches:

• Motor CIDP: IVIg should be considered first-line 1
• Antibody-mediated subtypes (anti-CNTN1, NF155, Caspr1, NF186/140): These "autoimmune nodopathies" respond poorly to IVIg; rituximab is preferred 7
• Distal CIDP, multifocal CIDP: Same first-line options as typical CIDP 1, 5

Common Pitfalls:

• Misdiagnosis is common—reconsider diagnosis if no treatment response 6
• Don't assume treatment failure if progression continues in first 4 weeks; progression might have been worse without therapy 4
• Distinguish TRFs (requiring retreatment) from primary non-response (requiring treatment switch) 4

Emerging Therapies

Efgartigimod alfa (FcRn antagonist) is newly FDA-approved for refractory CIDP, showing 61% reduction in relapses in the ADHERE study 8, 9. This represents a targeted option for patients failing conventional first-line therapies.

Adjunctive Management:

• Neuropathic pain requires specific pharmacologic treatment and multidisciplinary management 1
• Non-pharmacological interventions including physiotherapy should be initiated early 2