Long-term treatment with adalimumab in psoriatic arthritis: serum adalimumab concentration, immunogenicity and the link with clinical response.
OBJECTIVE
An observational study to evaluate the relationship between serum concentrations of adalimumab and disease activity in patients receiving long-term adalimumab treatment for psoriatic arthritis.


METHODS
Serum adalimumab and adalimumab antidrug antibodies were quantified by enzyme linked immunosorbent assay. Disease activity was assessed using Disease Activity Score (44 joint measures). Serum C-reactive protein was quantified using standard methods.


RESULTS
A total of 30 patients were recruited. There were significant inverse correlations between serum adalimumab concentration and serum C-reactive protein (CRP) concentration [r = -0.43], the number of tender joints (r = -0.4), and Disease Activity Score (DAS44)-CRP (r = -0.36). Mean serum adalimumab levels were significantly higher in patients with DAS44-CRP <1.6 than in patients with DAS44-CRP ≥1.6.


CONCLUSIONS
Serum adalimumab could be an important tool that may improve the management of psoriatic arthritis in patients responding to long-term treatment.
Rheumatology, Allergology and Clinical Immunology, Department of Systemic Medicine, University of Rome "Tor Vergata", Rome, Italy maria.sole.chimenti@uniroma2.it.
Maria Sole
MS
Chimenti
Rheumatology, Allergology and Clinical Immunology, Department of Systemic Medicine, University of Rome "Tor Vergata", Rome, Italy.
Paola
P
Triggianese
Dermatology, Department of Neurosciences, Mental Health, and Sensory (NESMOS), Sapienza - University of Rome, Rome, Italy.
Alessandra
A
Narcisi
Dermatology, Department of Systemic Medicine, University of Rome "Tor Vergata", Rome, Italy.
Barbara
B
Marinari
Dermatology, Department of Systemic Medicine, University of Rome "Tor Vergata", Rome, Italy.
Miriam
M
Teoli
Dermatology, Department of Systemic Medicine, University of Rome "Tor Vergata", Rome, Italy.
Sara
S
Faleri
Dermatology, Department of Neurosciences, Mental Health, and Sensory (NESMOS), Sapienza - University of Rome, Rome, Italy.
Annalisa
A
Arcese
Rheumatology, Allergology and Clinical Immunology, Department of Systemic Medicine, University of Rome "Tor Vergata", Rome, Italy.
Roberto
R
Perricone
Dermatology, Department of Neurosciences, Mental Health, and Sensory (NESMOS), Sapienza - University of Rome, Rome, Italy.
Antonio
A
Costanzo
Adalimumab; anti-drug antibodies; disease activity; immunogenicity; psoriatic arthritis; tumour necrosis factor-α
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