Abstract
Purpose :
Adalimumab is an effective treatment for many autoimmune conditions, including non-infectious uveitis (NIU). While therapeutic drug levels have been established for conditions like inflammatory bowel disease, data regarding therapeutic levels in NIU is limited.
We conducted an observational cross-sectional cohort study to investigate whether a therapeutic drug level for adalimumab could be determined for patients with NIU.
Methods :
Consecutive adult patients receiving adalimumab for NIU were recruited at from the Royal Victorian Eye and Ear Hospital and Eye Surgery Associates in Melbourne, Australia from March 2023 to August 2023. All patients had a blood sample tested for serum trough adalimumab level. “Active” uveitis was defined as having at least one of: anterior chamber cell ≥1+, vitreous haze ≥1+, active retinal or choroidal lesions, need for increased systemic or local therapy for uveitis, or presence of macular oedema.
Results :
We recruited 70 patients (37 females) with median age 45 years (range 19, 87years). Most had bilateral uveitis (N=65). The most common diagnoses were idiopathic, (N=22), sarcoidosis (N=12) and Vogt-Koyanagi-Harada disease (N=6).
Adalimumab dosing at the time of blood draw ranged from 80mg weekly (N=1), 40mg weekly (N=4), 40mg adalimumab fortnightly (N=56), 40mg three-weekly (N=7) or 40mg four-weekly (N=2). Forty patients were concurrently treated with conventional immunosuppression (e.g. methotrexate). Uveitis was deemed to be “active” in 22 patients at the time of testing.
Median serum adalimumab concentration was 4.5 µg/mL (IQR 2.6, 7.8; range 0.0-21.1). Most patients (N=37, 53%) had drug levels that would be considered subtherapeutic (<5 µg/mL) for other conditions such as inflammatory bowel disease.
Lower drug levels were associated with the presence of anti-drug antibodies (Spearman correlation rho = -0.366, p = 0.0018).We found no relationship between drug levels and concurrent uveitis activity or visual acuity, with a receiver operating characteristic curve analysis (Figure) determining an area under the curve of only 0.417 (95% CICI 0.259, 0.575).
Conclusions :
Low (<5 µg/mL) adalimumab drug levels were a common finding in our cohort, with no relationship found between serum drug levels and concurrent uveitis activity.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.