Improvement of hemoglobin levels after a switch from intravenous to subcutaneous administration of immunoglobulin in chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy

Subcutaneous immunoglobulins (SCIG) for chronic inflammatory demyelinating polyneuropathy (CIDP): A comprehensive systematic review of clinical studies and meta-analysis

BACKGROUND

Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) presents significant treatment challenges due to its chronic nature, varied clinical presentations, and rarity. Subcutaneous immunoglobulin (SCIG) has emerged as a maintenance therapy, offering potential advantages in administration and patient experience over the previously recognized intravenous immunoglobulin (IVIG).

METHODS

We included all clinical studies involving CIDP patients treated with SCIG from eleven databases up to March 2024.

RESULTS

50 clinical studies were included in the systematic review, with 22 involved in the meta-analysis. These studies offer clinical data on around 1400 CIDP patients. Almost all studies considered SCIG a maintenance therapy, with the majority of results suggesting it as a viable substitute that may offer comparable or enhanced advantages. Studies covered aspects such as efficacy, safety, quality of life, practicality, economic evaluation, and patient preference. Meta-analysis showed SCIG significantly improved muscle strength and sensory function, had fewer and milder side effects, reduced relapse rates, and received a strong preference.

CONCLUSIONS

Findings suggest that SCIG for CIDP maintenance not only provides a more feasible alternative, with economic evaluations showing considerable cost reductions over time, and patient preference for SCIG being pronounced, but may also deliver comparable or superior health outcomes. Ongoing research lines on formulations, techniques, and direct comparative studies are critical to further illuminate, enhance, and expand SCIG's role in treatment.

Subcutaneous immunoglobulin treatment for chronic inflammatory demyelinating polyneuropathy

Immunoglobulin G (IgG) therapy is an established long‐term treatment in chronic inflammatory demyelinating polyneuropathy (CIDP) that is commonly administered intravenously (IVIg). The subcutaneous immunoglobulin (SCIg) administration route is a safe and effective alternative option, approved by the United States Food and Drug Administration (FDA) in 2018, for maintenance treatment of adults with CIDP. Physicians and patients alike need to be aware of all their treatment options in order to make informed decisions and plan long‐term treatment strategies. In this review, we collate the evidence for SCIg in CIDP from all published studies and discuss their implications and translation to clinical practice. We also provide guidance on the practicalities of how and when to transition patients from IVIg to SCIg and ongoing patient support. Evidence suggests that IVIg and SCIg have comparable long‐term efficacy in CIDP. However, SCIg can provide additional benefits for some patients, including no requirement for venous access or premedication, and reduced frequency of systemic adverse events. Local‐site reactions are more common with SCIg than IVIg, but these are mostly well‐tolerated and abate with subsequent infusions. Data suggest that many patients prefer SCIg following transition from IVIg. SCIg preference may be a result of the independence and flexibility associated with self‐infusion, whereas IVIg preference may be a result of familiarity and reliance on a healthcare professional for infusions. In practice, individualizing maintenance dosing based on disease behavior and determining the minimally effective IgG dose for individuals are key considerations irrespective of the administration route chosen.

Long-term treatment with subcutaneous immunoglobulin in multifocal motor neuropathy

Multifocal motor neuropathy (MMN) is a rare disease with a prevalence of less than 1 per 100,000 people. Intravenous immunoglobulin (IVIG) therapy, performed for a long-term period, has been demonstrated able to improve the clinical picture of MMN patients, ameliorating motor symptoms and/or preventing disease progression. Treatment with subcutaneous immunoglobulin (SCIg) has been shown to be as effective as IVIG. However, previously published data showed that follow-up of MMN patients in treatment with SCIg lasted no more than 56 months. We report herein the results of a long-term SCIg treatment follow up (up to 96 months) in a group of 8 MMN patients (6 M; 2F), previously stabilized with IVIG therapy. Clinical follow-up included the administration of Medical Research Council (MRC) sum-score, the Overall Neuropathy Limitation Scale (ONLS) and the Life Quality Index questionnaire (LQI) at baseline and then every 6 months. Once converted to SCIg, patients’ responsiveness was quite good. Strength and motor functions remained stable or even improved during this long-term follow-up with benefits on walking capability, resistance to physical efforts and ability in hand fine movements.

Expanding the Role of the Pharmacist: Immunoglobulin Therapy and Disease Management in Neuromuscular Disorders

Immunoglobulin G (IgG) is a commonly used treatment for chronic neuromuscular disorders (NMDs), such as chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy. IgG therapy has also shown promise in treating other NMDs including myasthenia gravis, polymyositis, and dermatomyositis. IgG is administered as either intravenous immunoglobulin (IVIg) or subcutaneous immunoglobulin (SCIg), with SCIg use becoming more popular due to the treatment burden associated with IVIg. IVIg requires regular venous access; long infusions (typically 4-6 hours); and can result in systemic adverse events (AEs) for some patients. In contrast, SCIg can be self-administered at home with shorter infusions (approximately 1 hour) and fewer systemic AEs. As patient care shifts toward home-based settings, the role of the pharmacist is paramount in providing a continuation of care and acting as the bridge between patient and clinic. Pharmacists with a good understanding of current recommendations, dosing strategies, and administration routes for IgG therapy are best placed to support patients. The aims of this review are to highlight the evidence supporting IgG therapy in the treatment of NMDs and provide practical information on patient management and IVIg/SCIg dosing in order to guide pharmacists on optimizing clinical outcomes and patient care.

IgPro20, the Polyneuropathy and Treatment with Hizentra® study (PATH), and the treatment of chronic inflammatory demyelinating polyradiculoneuropathy with subcutaneous IgG

Subcutaneous IgG (SCIG) administration may be preferred over the intravenous route (IVIG) in chronic inflammatory demyelinating polyneuropathy (CIDP) because it minimizes ‘end of cycle’ treatment-related fluctuations, reduces systemic adverse effects, improves convenience/quality of life and potentially lowers overall costs. Early reports of the use of highly concentrated SCIG preparations suggested they were effective and well-tolerated in chronic inflammatory demyelinating polyneuropathy. This was confirmed in the Polyneuropathy and Treatment with Hizentra® study of 172 subjects randomized to receive maintenance therapy with placebo or one of two doses of IgPro20 (20% IgG stabilized with L-Proline) for 6 months. Risk of relapse was reduced by SCIG in a dose-related manner as compared with placebo. A total of 88% of polyneuropathy and treatment with hizentra subjects felt the subcutaneous method was ‘easy to learn’. Local adverse events were mostly mild or moderate, and systemic adverse events were infrequent. Some patients may prefer maintenance therapy with SCIG over IVIG.

Subcutaneous immunoglobulin treatment in CIDP and MMN. Efficacy, treatment satisfaction and costs

Subcutaneous administration of immunoglobulin (SCIG) in chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN) has been reported in several case reports and in a few randomized trials during the last decade. In this review we present the studies on SCIG in CIDP and MMN with special focus on the clinical effects. Moreover, the effect on quality of life, side effects to SCIG and the health economic perspectives are reviewed. Nine case studies, three randomized trials and six long-term, follow-up studies were identified. Most of the studies are conducted in patients switched from regular IVIG to SCIG treatment; one study involves treatment-naïve patients. The review shows that none of the studies have been powered to demonstrate an effect on disability. SCIG can maintain muscle strength for a period of 1 to 2years and ability seems preserved for a similar period. Quality of life is generally unchanged or improved after switch to SCIG and generalized side-effects seem fewer, whereas local reactions at the injection site occur. Health economic analyses favour SCIG at the doses used in the reviewed studies.

Early platelet and leukocyte decline in patients with neuroinflammatory disorders after intravenous immunoglobulins

BACKGROUND AND PURPOSE

Intravenous immunoglobulins (IVIGs) are a common therapy in patients with neuroinflammatory disorders, especially chronic inflammatory demyelinating polyradiculoneuropathy or Guillain-Barré syndrome. Hematological toxicities upon IVIG infusion are a known side effect and still an important subject of investigation.

METHODS

Laboratory results and data for clinical efficacy and tolerability of 62 patients with neuroinflammatory disorders treated with IVIG (0.4 g/kg bodyweight per day over 5 days) at the Department of Neurology, University of Duisburg-Essen, Germany, were retrospectively analyzed. Blood samples were taken before and 1 day after IVIG administration.

RESULTS

In pre-treated and first-time treated patients, there was a significant decrease in white blood cell count (WBC) (8.10 ± 2.85/nl to 5.61 ± 2.50/nl, P < 0.001, n = 57) and platelets (255 ± 72/nl to 215 ± 66/nl, P < 0.001, n = 57). Mild hemolysis of red blood cells was found in patients who received IVIG for the first time (red blood cell count 4.61 ± 0.67/pl to 4.28 ± 0.52/pl, hemoglobin 13.7 ± 1.7 g/l to 13.0 ± 1.7 g/l, P < 0.001, n = 40). Hemolysis was associated with less tolerability of IVIG treatment and clinical efficacy was accompanied with a higher decline of WBC (not significant).

CONCLUSIONS

Next to mild hemolysis, a significant decrease in WBC and platelets can be detected early after high dose IVIGs in patients with neuroinflammatory disorders. Changes in blood counts may be possible markers for clinical efficacy and tolerability. Patients with low blood counts in advance should be particularly closely monitored whilst on IVIG treatment.