Appropriate Use of Immunoglobulin in Managing Chronic Inflammatory Demyelinating Polyneuropathy

Debilitating and degenerative, chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare disease affecting 1.6 per 100,000 Americans annually. It most closely resembles Guillain-Barré syndrome and causes extremity nerve damage that reduces functioning. If untreated, about 30% of patients become wheelchair dependent. However, 70% to 90% of afflicted individuals can find some improvement with immunotherapy. CIDP was a session topic at the 2019 NASP Annual Meeting and Expo.

Two speakers gave a comprehensive presentation. Luigi Brunetti, PharmD, MPH, associate professor of pharmacy at Rutgers, The State University of New Jersey, emphasized that patients with CIDP have unique physical needs. Therefore, health care providers who see these patients need an empathetic, informed, team-based approach to care management. Although a neurologist usually leads the care team, patients also need support in the form of financial resources, health plan involvement, and a broad array of medical care.

Immunoglobulin is the only steroid-sparing lifelong treatment available at this time. Dr Brunetti indicated that if improvements are observed after patients are treated with immunoglobulin, mainly that they stabilize, experts propose various ways of continuing therapy. One leading researcher indicates that 75% of patients prescribed a 2-g/kg induction dose of intravenous immunoglobulin (IVIG) followed by IVIG 1 g/kg every 3 weeks for a maintenance dose remained stable without relapse. Another found that subcutaneous (SC) administration has been as effective in maintaining stability. In addition, it is convenient for some patients, and they report fewer adverse effects, less travel time, an absence of venous access problems, fewer “wearing off” fluctuations, and less time missed from work.

Dr Brunetti discussed the specialty pharmacist’s responsibilities. For this indication, immunoglobulin dosages, administration schedules, and infusion flow rates are different from those administered to patients with other diseases. Key points were the necessity of close monitoring to ensure that patients use appropriate amounts, providing vial sizes that reduce waste, and establishing an administration schedule that maximizes benefit and reduces costs. He stressed that patients with thrombosis, renal insufficiency, or renal failure must be monitored closely when using immunoglobulin products. Many prescribers and pharmacists are accustomed to using immunoglobulin products for other indications, but they need to be cautious because CIDP requires unique dosing and administration rates.

Amy Clarke, RN IgCN, director of Clinical Program Services, Nursing at Diplomat Specialty Infusion, discussed the economic implications important to specialty pharmacy. Research has found only a small difference in cost between the IVIG and SC immunoglobulin (SCIG). Outpatient immunoglobulin treatment is covered in the pharmacy budget, adding an element of increased control when clinicians employ drug utilization management. IV administration in a health care setting often falls into the buy-and-bill method of paying under the medical budget; this allows providers to add a percentage of the product’s cost onto the reimbursement, in addition to charging fees for providing services incident to the product. Regardless of where patients receive treatment, specialty pharmacists need to heighten their vigilance at transitions of care.

Ms Clarke stressed that for IV administration, patients need adequate venous access and clinicians need to monitor for infections in the port as well as in immunocompromised patients. For SC administration, patients need to have adequate SC tissue and be able to manipulate the syringe. Clinicians should assess the likelihood that the patient will adhere to treatment.

In summary, Ms Clarke reviewed key points. She came back to the session’s primary message: Appropriate use and accurate dosing of IVIG and SCIG for the treatment of CIDP are complicated and require meticulous risk assessment. Comorbidities, age, and the patient’s previous experience are considerations, as are premedication needs. Product selection must consider sodium and sugar content, pH, osmolarity, and concentration. There are also various means of administration, ancillary supplies, and possible challenges. Home care models differ, too, as do inpatient policies. Specialty pharmacists need to be aware of differences in approaches to care, identify steps in processes that create risk, and ensure that everyone is on the same page.