Shared challenges in the management of difficult-to-treat chronic inflammatory diseases: expert perspectives

The concept of difficult-to-treat (D2T)/difficult-to-manage (DTM) disease was first defined in rheumatoid arthritis (RA). Recent definitions for axial spondyloarthritis (axSpA) and psoriatic arthritis (PsA) combine non-response to treatment including targeted and biologic treatment, inflammatory disease activity, and patient symptoms. This concept could apply to other chronic inflammatory diseases such as psoriasis (PsO) and inflammatory bowel disease (IBD). A consensus definition of D2T IBD is available but is yet to be fully articulated in PsO.

This article aims to provide an expert overview of the shared elements and potential differences between the definitions and concepts of D2T/D2M in these diseases.

D2T/D2M definitions should allow better evaluation of refractory diseases, accurate determination of disease severity, and effective treatment of the D2T areas or domains. Definitions should consider response to previous lines of treatment, control of inflammation, and global disease improvement, and consider the impact of D2T disease on patient status/quality of life. Proof-of-concept studies need to assess the current and future definitions of D2T/D2M populations in axSpA, PsA, PsO, and IBD, to accurately determine the prevalence of patients meeting each of those D2T criteria sets, and to identify risk factors, disease burden, and appropriate management strategies.