Israel Medical Association Journal

Background: The parasympathetic system and its main neurotransmitter, acetylcholine, contributes to homeostasis of inflammation. Cholinergic dysregulation is thought to contribute to the pathogenesis of inflammatory rheumatic diseases. Cholinesterase activity in patients with psoriatic arthritis (PsA) has not been investigated.

Objectives: To compare the cholinesterase activity in patients with PsA and immunocompetent controls and to explore the correlation between cholinergic status (CS) and PsA disease activity.

Methods: Serum acetylcholinesterase (AChE) and total cholinesterase activity were measured in patients with PsA (n=88) and matched controls (n=84). Cholinergic activity before and 3–6 months after the initiation of a biologic treatment was evaluated in seven patients with PsA.

Results: The levels of AChE and CS were similar in both PsA patients and controls. PsA patients treated with biologics had significantly lower levels of AChE and CS compared to patients treated with non-biologics: 447.4 vs. 526 substrate hydrolyzed/min/ml, P = 0.005, and 1360.9 vs. 1536, P = 0.029, respectively. We found an association between C-reactive protein levels, AChE activity (r = 0.291, P = 0.008), and cholinergic status (r = 0.247, P = 0.026) in patients with PsA but not in controls. No correlation between AChE activity, cholinergic status, and the indices of PsA disease activity was found. After initiating or switching biologic treatment in 7 patients, AChE levels remained stable.

Conclusions: We demonstrated similar cholinesterase activity in patients with psoriatic arthritis and controls, highlighting a potential effect of biologic treatment on cholinergic activity in patients with PsA.

Background: Tocilizumab is an interleukin 6 (IL-6) receptor antagonist used treat moderate to severe active rheumatoid arthritis (RA). Both intravenous (IV) and subcutaneous (SC) routes are approved for the treatment of adults with RA.

Objectives: To evaluate SC tocilizumab in a real-life clinical setting.

Methods: Our study was a multi-center, open-label, single-arm study. Participants were adults with a diagnosis of active RA, previously treated with disease-modifying antirheumatic drugs (DMARDs), with or without biologic agents. Participants received a weekly SC injection of tocilizumab 162 mg as monotherapy or in combination with methotrexate or DMARDs for 24 weeks. Efficacy, safety, and immunogenicity were assessed.

Results: Treatment of 100 patients over 24 weeks resulted in improvement in all efficacy parameters assessed: Clinical Disease Activity Index, Disease Activity Score using 28 joint counts and erythrocyte sedimentation rate, American College of Rheumatology response scores, Simplified Disease Activity Index, tender and swollen joint counts, and patient-reported outcomes including fatigue, global assessment of disease activity, pain, and Health Assessment Quality of Life Disease Index. Improvement was achieved as early as the second week of treatment. There were 473 adverse events (AEs)/100 patient-years (PY) and 16.66 serious AEs/100 PY. The most common AEs were neutropenia (12%), leukopenia (11%), and increased hepatic enzymes (11%). Of a total of 42 PY, the rates of serious infections and AEs leading to discontinuation were 4.8, and 11.9 events/100 PY, respectively.

Conclusions: The safety, tolerability, and efficacy profile of tocilizumab SC were comparable to those reported in other studies evaluating the IV and SC routes of administration.