Therapies in Autoimmune Peripheral Neuropathies beyond Intravenous Immunoglobulin, Plasma Exchange and Corticosteroids: An Analytical Review

Autoimmune neuropathies are often treatable. First-line immunotherapies include intravenous immunoglobulin (IVIG), plasma exchange and corticosteroids. However, nearly 15-30% of patients are either refractory, partially responsive or chronically dependent on these first-line agents. Lack of full response leads to increased disability in addition to adverse financial implications. Consequently, there is an unmet need for more effective treatments to manage this subset of patients. There has been a remarkable increase in the knowledge about immunopathogenesis, antigenic targets, clinical phenotype correlation, and novel therapeutic agents in the last two decades. These novel agents target specific components of the immune system (humoral, cellular immunity, and complement) and have the potential to improve the management of these disorders. Unfortunately, high-quality evidence from large, controlled studies is scarce considering the relative rarity of these refractory cases, heterogeneity of clinical presentations and ethical concerns limiting the use of a placebo arm. An adaptive clinical trial design in a homogenous cohort with standardized outcomes in multiple centers and the use of historical controls will likely provide valuable scientific evidence about the efficacy and safety of these therapies. In this review, we examine the status of the newer immunotherapies in the treatment of autoimmune neuropathies based on existing data.