Etanercept in psoriatic arthritis

Psoriatic arthritis: review of potential biomarkers predicting response to TNF inhibitors

Psoriatic arthritis (PsA) is a chronic and painful inflammatory immune-mediated disease. It affects up to 40% of people with psoriasis and it is associated with several comorbidities such as obesity, diabetes, metabolic syndrome, and hypertension. PsA is difficult to diagnose because of its diverse symptoms, namely axial and peripheral arthritis, enthesitis, dactylitis, skin changes, and nail dystrophy. Different drugs exist to treat the inflammation and pain. When patients do not respond to conventional drugs, they are treated with biologic drugs. Tumour necrosis factor inhibitors (TNFi's) are commonly given as the first biologic drug; beside being expensive, they also lack efficacy in 50% of patients. A biomarker predicting individual patient's response to TNFi would help treating them earlier with an appropriate biologic drug. This study aimed to review the literature to identify potential biomarkers that should be investigated for their predictive ability. Several such biomarkers were identified, namely transmembrane TNFα (tmTNF), human serum albumin (HSA) and its half-life receptor, the neonatal Fc receptor (FcRn) which is also involved in IgG lifespan; calprotectin, high mobility group protein B1 (HMGB1) and advanced glycation end products (AGEs) whose overexpression lead to excessive production of pro-inflammatory cytokines; lymphotoxin α (LTα) which induces inflammation by binding to TNF receptor (TNFR); and T helper 17 (Th17) cells which induce inflammation by IL-17A secretion.

Clinical Pharmacokinetics of Etanercept: A Fully Humanized Soluble Recombinant Tumor Necrosis Factor Receptor Fusion Protein

Etanercept, a fully humanized soluble recombinant tumor necrosis factor receptor fusion protein, is an approved treatment for rheumatoid arthritis, juvenile rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and psoriasis. Etanercept is absorbed slowly from the site of subcutaneous injection, with time to peak concentration at approximately 48 to 60 hours, and is cleared slowly from the body with a t(1/2) of 70 to 100 hours. The absolute bioavailability of etanercept was 58% in healthy subjects following subcutaneous administration. The 25-mg twice-weekly dosage regimen generates systemic exposures comparable to 50 mg once weekly, as predicted by pharmacokinetic modeling and simulation and later confirmed by clinical studies. The pharmacokinetics of etanercept in patients with rheumatoid arthritis are comparable to those in healthy individuals and patients with ankylosing spondylitis, congestive heart failure, and psoriasis. In children with polyarticular-course juvenile rheumatoid arthritis, after subcutaneous doses of 0.4 mg/kg twice weekly, the clearance of etanercept may be slightly reduced in children aged 4 to 8 years. Pharmacokinetic simulation predicts that a dose of 0.8 mg/kg once weekly generates comparable systemic exposure as 0.4 mg/kg twice weekly. No requirement for etanercept dosage adjustment is needed when etanercept is coadministered with warfarin, digoxin, or methotrexate.

The diagnosis and treatment of early psoriatic arthritis

Psoriatic arthritis (PsA) is a chronic inflammatory musculoskeletal disorder associated with a heterogeneous disease presentation, varied disease expression and an unpredictable but often chronically destructive clinical course. Joint damage can occur early in the disease; indeed, several imaging modalities have demonstrated subclinical joint involvement in psoriasis patients without musculoskeletal signs or symptoms. Efforts are underway to validate questionnaires that will enable dermatologists to screen patients with psoriasis for the presence of musculoskeletal disease. To date, the use of therapies in patients with early PsA has not been reported in randomized controlled trials. Moreover, conventional agents are partially effective in established PsA but, in general, trials with DMARDS have not included validated outcome measures for the different manifestations of PsA. Tumor necrosis factor antagonists can alleviate the signs and symptoms of established psoriatic arthritis and inhibit radiographic progression, but the therapeutic impact of early intervention with these agents requires further study. The extent of disease and the presence of comorbidities should be used to guide treatment decisions and to minimize adverse events.

Effects of etanercept in patients with the metabolic syndrome

BACKGROUND

Adipose-derived cytokines, including tumor necrosis factor alpha, may contribute to the inflammation that occurs in the metabolic syndrome. We investigated the effects of inhibition of tumor necrosis factor alpha with etanercept in patients with the metabolic syndrome.

METHODS

Fifty-six subjects with the metabolic syndrome were randomized to administration of either etanercept or identical placebo, 50 mg subcutaneously once a week for 4 weeks. The C-reactive protein level was the primary end point. Effects on other inflammatory markers (including fibrinogen, interleukin 6, and adiponectin), insulin sensitivity, lipid levels, and body composition were also determined.

RESULTS

Baseline characteristics were similar between the groups. Two subjects dropped out of each group, and etanercept was well tolerated throughout the study. The C-reactive protein levels decreased significantly in the treated compared with the placebo group (-2.4 +/- 0.4 vs 0.5 +/- 0.7 mg/L; P<.001). Adiponectin levels rose significantly in the etanercept group compared with the placebo group (0.8 +/- 0.4 vs -0.3 +/- 0.3 microg/mL; P = .03). Fibrinogen levels decreased (-68 +/- 16 vs -2 +/- 31 mg/dL [-2.0 +/- 0.47 vs -0.06 +/- 0.91 micromol/L]; P = .04) and interleukin 6 levels tended to decrease (-1.2 +/- 0.8 vs 0.5 +/- 0.5 ng/L; P = .07) in the etanercept-treated subjects compared with placebo, respectively. No changes occurred in body composition parameters or insulin sensitivity, but high-density lipoprotein levels tended to decrease in the etanercept group (-1 +/- 1 vs 2 +/- 1 mg/dL [-0.03 +/- 0.03 vs 0.05 +/- 0.03 mmol/L]; P = .06) compared with the placebo group.

CONCLUSIONS

Etanercept reduces C-reactive protein levels and tends to improve other inflammatory cardiovascular risk indexes in patients with the metabolic syndrome. Etanercept may interrupt the inflammatory cascade that occurs with abdominal obesity. Further, longer-term studies are needed to determine the effects of tumor necrosis factor alpha inhibition on cardiovascular disease in patients with the metabolic syndrome.

Etanercept: a clinical review of current and emerging indications

The recent development of inhibitors of TNF-alpha has provided the opportunity for a more targeted and highly effective approach to the treatment of chronic inflammatory illnesses such as rheumatoid arthritis. Since the initial approval of etanercept as a treatment for rheumatoid arthritis, additional indications, including psoriatic arthritis, juvenile rheumatoid arthritis and ankylosing spondylitis, have also received FDA approval. More than 220,000 patients have been treated with etanercept so far. This review summarises the body of knowledge accumulated so far on etanercept (Enbrel) since it entered the market 5 years ago.

Psoriatic arthritis and psoriasis: Need for a multidisciplinary approach

Psoriatic arthritis is a progressive and often destructive form of seronegative inflammatory arthritis that is associated with psoriasis. It can be difficult to diagnose because it can present in a number of different ways, often indistinguishable from noninflammatory arthropathies such as osteoarthritis as well as inflammatory arthritis such as gout. Severe arthritis may be observed in the absence of psoriasis, or mild arthritis may be seen in the presence of moderate-to-severe psoriasis. A high index of suspicion, screening of psoriasis patients, and close follow-up and evaluation with rheumatology often is needed to make the diagnosis. Early recognition of the disorder and timely therapy can prevent long-term complications, such as permanent joint destruction and disability. With the advent of biologic agents, we are better equipped to manage psoriatic arthritis today. Because dermatologists are on the front-line of psoriasis management, we are perfectly poised to identify and help improve care for patients who suffer from both psoriasis and psoriatic arthritis.