From the FDA Drug Label
Rheumatoid Arthritis and Psoriatic Arthritis: Patients in Studies RA-I, RA-II, and RA-III were tested at multiple time points for antibodies to adalimumab using the ELISA during the 6- to 12-month period
- The antibodies associated with Psoriatic Arthritis (PsA) are antibodies to adalimumab.
- The development of these antibodies may affect the efficacy of the treatment, as the ACR 20 response was lower among antibody-positive patients than among antibody-negative patients 1.
From the Research
Psoriatic arthritis is typically characterized by a seronegative status, meaning patients usually test negative for rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibodies, although some studies suggest that a small percentage of patients may be positive for these antibodies, particularly those with more severe disease or polyarticular involvement 2, 3. The presence of anti-CCP antibodies in psoriatic arthritis patients has been investigated in several studies, with varying results. A study published in 2020 found that anti-CCP antibodies were present in 17.1% of psoriatic arthritis patients, and were associated with older age, lung involvement, and higher RF and MMP-3 titers 2. Another study published in 2019 found that RF or anti-CCP antibody positive psoriatic arthritis patients were older and had more joint involvement, particularly in the metacarpophalangeal, elbow, and shoulder joints 3. Some studies have also investigated the presence of other antibodies in psoriatic arthritis patients, such as anti-carbamylated protein antibodies (anti-CarP) and antibodies against peptidyl arginine deiminase type 4 (PAD4) 4, 5. However, these antibodies are not currently used in routine clinical practice for diagnosing or managing psoriatic arthritis. Key points to consider when evaluating the antibody status of psoriatic arthritis patients include:
- The majority of psoriatic arthritis patients are seronegative, meaning they test negative for RF and anti-CCP antibodies
- A small percentage of patients may be positive for these antibodies, particularly those with more severe disease or polyarticular involvement
- The presence of anti-CCP antibodies may be associated with older age, lung involvement, and higher RF and MMP-3 titers
- Other antibodies, such as anti-CarP and anti-PAD4, are not currently used in routine clinical practice for diagnosing or managing psoriatic arthritis In clinical practice, diagnosis and treatment decisions for psoriatic arthritis should be based on a comprehensive evaluation of the patient's symptoms, medical history, and imaging findings, rather than relying solely on antibody testing 4, 5, 2, 6, 3.