New Biomarkers and Therapeutics Show Potential in Still's Disease Save

Adult-onset Still’s disease (AOSD) is a rare complex, sporadic, systemic autoinflammatory disease similar to systemic juvenile idiopathic arthritis (sJIA) characterized by sustained fever, salmon-colored rash, and arthritis. AOSD and sJIA are considered the same spectrum of disease with similar pathophysiology occurring in different age groups. Both are characterized by the classic triad of fevers, joint pain, and a distinctive salmon-colored rash. The 2023 American College of Rheumatology (ACR) convergence featured several abstracts spotlighting developments in understanding and managing this complex disease spectrum.

Abstract 0282 discusses a potential biomarker = DNA methylation levels that can be low in Still's disease and the authors have identified six differential methylated sites (DMSs) between AOSD and healthy controls/disease controls. In a disease that often has delayed diagnosis due to its heterogeneity and delayed referrals, biomarkers may become a game changer.  Further research is needed to see if these can be validated and used in mainstream clinical practice.

There were also some therapeutics discussed about clinical management of patients who develop complications of Still's disease such as macrophage activation syndrome (MAS). 

Abstract 0760 discusses MAS, a rare but potentially life-threatening complication of Still's disease. The hallmark of MAS is the overproduction of proinflammatory cytokines, such as interferon gamma (IFNγ). Since the availability of the drug Emapalumab which is an anti-IFNγ antibody many clinicians have been using it for the treatment of MAS. This abstract describes A retrospective medical chart review of patients who were given this treatment likely as an off-label therapy.  This review was conducted in 33 hospitals US wide to identify patients who at least got one dose of emapalumab. Of 105 pts who got this medication - 10 had Still’s disease (sJIA, n=9; AOSD, n=1) Overall survival and 12-month survival probability following emapalumab initiation was 90% (9/10) for patients with Still’s disease. One patient died due to uncontrolled viremia, which was deemed by the investigator to be unrelated to the clinical condition for which emapalumab was used. Thus, making emapalumab a potential game changer in a condition which is very difficult to treat clinically.

These revelations from the ACR 2023 convergence signify a significant stride forward in understanding and managing Still's disease, offering new avenues for diagnosis and targeted therapeutics in a condition notorious for its clinical intricacies. Further research will be crucial to validate and integrate these findings into routine clinical practice.