Obesity Negatively Affects Treatment Response to JAK Inhibitors in RA

Patients treated with JAK inhibitors for rheumatoid arthritis may be less likely to have low disease activity if they are obese compared with those who are overweight.
The following article is part of conference coverage from the 2018 American College of Rheumatology and Association of Rheumatology Health Professionals (ACR/ARHP) Annual Meeting in Chicago, Illinois. Rheumatology Advisor’s staff will be reporting breaking news associated with research conducted by leading experts in rheumatology. Check back for the latest news from ACR/ARHP 2018 .

CHICAGO — Patients treated with Janus kinase (JAK) inhibitors for rheumatoid arthritis (RA) may be less likely to have low disease activity if they are obese compared with those who are overweight, according to a study presented at the 2018 ACR/ARHP Annual Meeting, held October 19-24, in Chicago, Illinois.

Using data from a German prospective longitudinal observational cohort, Rheumatoid Arthritis: Observation of Biologic Therapy (RABBIT), in which patients with RA are enrolled when initiating treatment with biologics, biosimilars, JAK inhibitors, or new conventional synthetic disease-modifying antirheumatic drugs, researchers examined the impact of body mass index (BMI) on achieving low disease activity in patients treated with JAK inhibitors. Low disease activity was defined as a score <3.2 on the 28-joint Disease Activity Score with erythrocyte sedimentation rate (DAS28-ESR).

A total of 539 patients who initiated tofacitinib (n=184; 34%) or baricitinib (n=355; 66%) between March 2017 and April 2018 were categorized into obese (BMI ≥30 mg/m2), overweight (BMI between 25 and 30 mg/m2), and normal weight (BMI <25 mg/m2). Time of JAK inhibitor treatment initiation was considered as baseline. Of the 217 patients for whom all information necessary for analysis was available, low disease activity was achieved within the first 6 months of JAK inhibitor therapy initiation by 19% of obese patients, 41% of overweight patients, and 42% of normal weight patients. Remission rates, defined as a DAS28 score <2.6, were 11% for obese patients, 24% for overweight patients, and 20% for normal weight patients. The regression model indicated a significant negative effect of obesity on low disease activity achievement compared with normal weight. The odds of achieving low disease activity were increased in individuals with no prior biologic treatment and better physical functioning at baseline. Neither the dosage of JAK inhibitors nor combination/mono-therapy had an effect on treatment response.

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Study investigators conclude that “obesity but not overweight had a negative impact on the achievement of [low disease activity] in [patients with RA] treated with JAK [inhibitors]. Further studies are needed to investigate factors that affect treatment response in obese patients.”

Numerous researchers claim affiliation with the pharmaceutical industry. Please see the source for a complete list of disclosures.

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Meißner Y, Baganz L, Schneider M, et al. Baricitinib and tofacitinib in real life – does obesity impact response to Janus kinase inhibitor therapy in rheumatoid arthritis? Presented at: 2018 ACR/ARHP Annual Meeting; October 19-24, 2018; Chicago, IL. Abstract 1518.

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