Review article: Novel therapies in inflammatory bowel disease - An update for clinicians.

BACKGROUND: Several new treatments including small molecules and biologics have been approved for the treatment of inflammatory bowel diseases in recent years. Clinicians and patients now have a wide variety of therapeutic options to choose from and these novel therapies provide several advantages including oral administration, lower immunogenicity, better selectivity and arguably better safety profiles. An increase in treatment options has increased the complexity of decision-making. Both patients and clinicians have had to become rapidly familiar with efficacy of new medications balanced against a range of pre-initiation requirements, dosing schedules and adverse event profiles. AIMS: To provide a simple guide to practising clinicians on recently approved and emerging therapies and address key challenges around treatment strategies such as optimal sequencing and timing of treatment. METHODS: We comprehensively searched the published literature and major conference abstracts to identify phase III placebo-controlled and active comparator trials for Crohn's disease and ulcerative colitis. RESULTS: Data for recently approved therapies including selective Janus kinase inhibitors, sphingosine-1 receptor modulators and p19 interleukin (IL)-23 inhibitors have demonstrated improved patient outcomes in both Crohn's disease and ulcerative colitis. Further comparative head-to-head studies have improved our understanding of when and how to optimally use newer therapies, specifically for IL-23 inhibitors. Data for emerging treatment options and novel treatment strategies such as early effective treatment, combinations of treatments and implications for sequencing are continuing to transform IBD care continually. CONCLUSIONS: Recently approved novel therapies have expanded the range of medical options available to treat IBD. However, further data from long-term extension studies, real-world studies and head-to-head trials are warranted to better inform the long-term safety and optimal sequencing of treatments for patients living with IBD.

Autoimmune Pathology in Myasthenia Gravis Disease Subtypes Is Governed by Divergent Mechanisms of Immunopathology.

Myasthenia gravis (MG) is a prototypical autoantibody mediated disease. The autoantibodies in MG target structures within the neuromuscular junction (NMJ), thus affecting neuromuscular transmission. The major disease subtypes of autoimmune MG are defined by their antigenic target. The most common target of pathogenic autoantibodies in MG is the nicotinic acetylcholine receptor (AChR), followed by muscle-specific kinase (MuSK) and lipoprotein receptor-related protein 4 (LRP4). MG patients present with similar symptoms independent of the underlying subtype of disease, while the immunopathology is remarkably distinct. Here we highlight these distinct immune mechanisms that describe both the B cell- and autoantibody-mediated pathogenesis by comparing AChR and MuSK MG subtypes. In our discussion of the AChR subtype, we focus on the role of long-lived plasma cells in the production of pathogenic autoantibodies, the IgG1 subclass mediated pathology, and contributions of complement. The similarities underlying the immunopathology of AChR MG and neuromyelitis optica (NMO) are highlighted. In contrast, MuSK MG is caused by autoantibody production by short-lived plasmablasts. MuSK MG autoantibodies are mainly of the IgG4 subclass which can undergo Fab-arm exchange (FAE), a process unique to this subclass. In FAE IgG4, molecules can dissociate into two halves and recombine with other half IgG4 molecules resulting in bispecific antibodies. Similarities between MuSK MG and other IgG4-mediated autoimmune diseases, including pemphigus vulgaris (PV) and chronic inflammatory demyelinating polyneuropathy (CIDP), are highlighted. Finally, the immunological distinctions are emphasized through presentation of biological therapeutics that provide clinical benefit depending on the MG disease subtype.