Correlation between Adalimumab concentration, anti-drug antibody and clinical efficacy in rheumatoid arthritis and...

To detect anti-drug antibody (ADA), Neutralizing Antibody (NAb) and Adalimumab (ADL) concentration in Rheumatoid arthritis (RA) and Ankylosing spondylitis (AS) and investigate correlations with clinical efficacy.

78 active RA patients, 59 active AS patients and 30 age, sex matched healthy individuals were recruited. The treatment course was 24 weeks with assessments every 12 weeks. ADL concentration, ADA and NAb were measured by enzyme-linked immunosorbent assay (ELISA). SPSS 26.0 was applied for statistical analysis.

The ADA incidence in AS group was higher than that in RA group after 24 weeks of treatment. The ADL concentration in AS/RA group with ADA was lower than that without ADA after 12/24 weeks of treatment. At 24 weeks of treatment: In RA group, the Remission-Low activity group's ADL concentration was higher than that of the Moderate-Severe activity group, and the ADA positive rate was lower (χ²=4.481, P = 0.034). In AS group, the Remission-Low activity group's ADL concentration was higher than that of the High-Extreme high activity group, and the ADA positive rate was lower (χ²=5.184, P = 0.023). Logistic regression analysis showed that ADA at 12/24 weeks and disease course were risk factors for Moderate-Severe activity status in RA group and High-Extreme high activity status in AS group. In contrast, log₁₀(ADL concentration) at 24 weeks was a protective factor in RA, and log₁₀(ADL concentration) at 12 and 24 weeks were protective factors in AS.

The total incidence of ADA, which is almost entirely NAb in RA and AS patients at 24 weeks after ADL treatment, is approximately 20%. AS patients show higher ADA incidence than RA patients. ADA correlates with lower ADL concentration and is closely related to disease activity.