IL-6 and JAK Inhibitors Effective for Treatment of Rheumatoid Arthritis With Anemia

Treatment with interleukin-6 (IL-6) receptor inhibitors and Janus kinase (JAK) inhibitors in a real-world setting appears to be effective among patients with rheumatoid arthritis (RA) and anemia, according to study findings published in Rheumatology.

Investigators evaluated patients with RA and anemia treated with biological/targeted synthetic disease-modifying antirheumatic drugs (b/ts-DMARDs) and assessed changes in baseline hemoglobin (Hb) levels, drug retention rates, and disease activity scores.

A retrospective cohort study was conducted and included patients from a Japanese registry with RA who had data on Hb levels and clinical disease activity index (CDAI) scores, treated with bDMARDs or JAK inhibitors.

Block design was used to first stratify patients by sex, as women typically have lower Hb levels than men. Patients were then stratified by baseline Hb levels into 3 tertials: low Hb(classified as anemic), intermediate Hb, and high Hb (classified as non-anemic).

Primary outcomes included overall and 3-year drug retention rates of 3 bDMARD categories (TNF inhibitors, IL-6 receptor inhibitors, and immunoglobulin fused with cytotoxic T-lymphocyte antigen [CTLA-4-IG]) and JAK inhibitors.

A total of 2093 patients were included in the analysis; 359 were men and 1734 were women. The investigators noted TNF inhibitors were frequently used concomitantly with methotrexate, while JAK inhibitors were less often used in patients who were bio-naïve, and CTLA-4-Ig was often used in patients of more advanced age.

Among patients with RA in the low and intermediate Hb groups, Hb levels increased with TNF inhibitors and CTLA-4-Ig, while levels remained unchanged in the high Hb group.

Among all 3 Hb groups, IL-6 receptor inhibitors increased Hb levels from baseline to 12 months.

While JAK inhibitors were found to increase Hb levels among the low Hb group, levels were found to decrease in the high Hb group and remained unchanged in the intermediate Hb group.

In subgroup analysis of patients with RA aged at least 50 years (n=1301 women; n=303 men), results were the same as in the overall analysis for IL-6 receptor inhibitors (Hb levels increased in all Hb groups) and JAK inhibitors (Hb levels increased in the low Hb group, decreased in high Hb group, did not change in intermediate Hb group).

Investigators noted the highest overall adjusted 3-year drug retention rates in patients with RA and anemia occurred with JAK inhibitors (78.6%), IL-6 receptor inhibitors  (67.9%), CTLA-4-Ig (61.8%), and TNF inhibitors (50.8%). No differences were found in disease activity changes at 12 months among b/ts-DMARDs treatments.

Study limitations included the retrospective design, potential confounding variables, and unregulated/unmonitored b/ts-DMARD doses and frequencies.

The study authors concluded, [P]atients with anaemia and RA are at risk of joint damage and inadequate treatment outcomes. Hence, it is important to determine which b/ts-DMARDs are most appropriate for treating patients with anaemia and RA.”

Disclosure: One or more of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.