SUMMARY
Obesity-Induced Inflammatory Mediators Predict Lack of Response in Patients with Rheumatoid Arthritis
Starting Biological Therapies
There is an unmet need to identify predictive biomarkers in rheumatoid arthritis (RA) with respect to outcome
and response to therapy. Numerous efforts to identify patients who will respond well to specific biologic agents
have begun to yield profiles that might allow more personalized use of these agents, but much more work needs
to be done. Given the complexity and heterogeneity of RA, it seems doubtful that a single cytokine or biomarker
will be sufficient to inform the optimal choice of therapy. Instead, the inclusion of multiple biomarkers into
‘biomarker signatures’ may represent a more fruitful approach for the future of personalized therapeutic
approaches.
While clinical factors predicting disease outcomes are few, prior studies have highlighted strong associations
between body weight and RA outcomes, although the mechanisms behind these associations are not defined.
Obesity-induced inflammatory mediators include both proteins (such as adipokines) and lipids (such as fatty
acid–derived bioactive lipids). Both types of obesity-induced mediators have been hypothesized to predict clinical
responses in patients with RA, either by directly contributing to lack of response by promoting subclinical
inflammation and disease relapse, or by describing metabolic phenotypes that may have prognostic value. Prior
studies from our and other groups have described bioactive lipids disturbances in early stages of RA that are
linked to therapeutic response.
Additional preliminary results on samples from Comparative Effectiveness Registry to Study Therapies
for Arthritis and Inflammatory (CERTAIN) cohort, revealed that distinct bioactive lipid profile (including those in
the prostaglandin, leukotriene, resolvin, and eicosatrienoate pathways) was associated with response to different
biologic therapies (categorized by minimal clinically important difference (MCID) in Clinical Disease Activity Index
(CDAI) at 6 months after treatment initiation). Of interest, one of them, the 15-oxoEDE, which derives from
eicosadienoic acid, a n-6 polyunsaturated fatty acid (PUFA) that has been associated with obesity and diabetes,
was associated with both lack of response to anti-TNF therapy and obesity in the CERTAIN cohort. Taken
together, our work suggests that obesity-induced inflammatory mediators profiling has the potential to identify
metabolic phenotypes and effectively predict patient response to therapy prior to administration, and has also
the potential to identify metabolic pathways that relate to response to biological therapies with distinct
mechanisms of action.
