Will treatment of rheumatoid arthritis with an IL-6R inhibitor help facilitate the ‘age of remission’?

Treatment of rheumatoid arthritis with traditional chinese medicine

Rheumatoid arthritis (RA) is a chronic inflammatory disease that will affect quality of life and, working efficiency, and produce negative thoughts for patients. Current therapy of RA is treated with disease-modifying antirheumatic drugs (DMARDs). Although most of these treatment methods are effective, most patients still have a pleasant experience either due to poor efficacy or side effects or both. Interleukin-6 receptor (IL6R) is important in the pathogenesis of RA. In this study, we would like to detect the potential candidates which inhibit IL6R against RA from traditional Chinese medicine (TCM). We use TCM compounds from the TCM Database@Taiwan for virtually screening the potential IL6R inhibitors. The TCM candidate compound, calycosin, has potent binding affinity with IL6R protein. The molecular dynamics simulation was employed to validate the stability of interaction in the protein complex with calycosin. The analysis indicates that protein complex with calycosin is more stable. In addition, calycosin is known to be one of the components of Angelica sinensis, which has been indicated to have an important role in the treatment of rheumatoid arthritis. Therefore, calycosin is a potential candidate as lead compounds for further study in drug development process with IL6R protein against rheumatoid arthritis.

Tocilizumab for the treatment of rheumatoid arthritis

Tocilizumab is a humanized anti-IL-6 receptor monoclonal antibody, which binds to circulating soluble IL-6 receptor and membrane-expressed IL-6 receptor, inhibiting IL-6 binding to both forms of IL-6 receptor. Several Phase III clinical trials demonstrate the clinical efficacy of tocilizumab as monotherapy or with disease-modifying anti-rheumatic drugs for adult patients with moderately to severely active rheumatoid arthritis. Tocilizumab in combination with methotrexate after 24 weeks of treatment could induce disease remission in 30% of patients with rheumatoid arthritis refractory to anti-TNF antagonist therapy. The most common adverse reactions reported in clinical studies are upper respiratory tract infection, nasopharyngitis, headache, hypertension and mild, reversible increases in alanine aminotransferase enzymes. Serious adverse reactions include infections, gastrointestinal perforations and hypersensitivity reactions, including anaphylaxis. The clinical efficacy and safety of tocilizumab has led to the approval of this innovative drug for the treatment of rheumatoid arthritis in more than 70 countries worldwide.

Clinical safety of tocilizumab in rheumatoid arthritis

IMPORTANCE OF THE FIELD

Tocilizumab is a new biologic disease-modifying antirheumatic drug directed against the activity of IL-6, a key pro-inflammatory cytokine in the pathogenesis of rheumatoid arthritis (RA). This drug has proved highly effective in RA patients, including those who had previously not responded to anti-TNFs. As side effects are a major cause for discontinuing biologic therapy, the present article focuses on the tolerability profile of tocilizumab.

AREAS COVERED IN THIS REVIEW

This review describes the adverse events (AEs) reported in RA patients treated with tocilizumab. Most data are derived from controlled clinical trials and their open-label extensions.

WHAT THE READER WILL GAIN

The reader will gain a comprehensive review of treatment-emergent AEs associated with tocilizumab therapy. These AEs include infections, including opportunistic infections, infusion and hyper-sensitivity reactions, gastrointestinal perforation, and laboratory test abnormalities, especially hepatic transaminase elevations, altered lipid profile and neutropenia.

TAKE HOME MESSAGE

Based on current data, tocilizumab appears to have an acceptable safety profile inasmuch as most AEs were manageable or controllable. However, results from large scale pharmacoepidemiological investigations and appropriate post-marketing surveillance are awaited to identify the full spectrum of AEs and define the true benefit:risk ratio of tocilizumab.

Risk of adverse events including serious infections in rheumatoid arthritis patients treated with tocilizumab: a systematic literature review and meta-analysis of randomized controlled trials

OBJECTIVE

To assess the risk of adverse events (AEs) in patients with RA treated with tocilizumab, an IL-6 receptor antibody, in published randomized controlled trials (RCTs).

METHODS

A systematic literature search was conducted using the Cochrane library, PUBMED and EMBASE for all RCTs (of the use of tocilizumab for RA) until September 2009. Fixed effect meta-analyses were conducted to compare the incidence of AEs after treatment with tocilizumab 8 and 4 mg/kg in combination with MTX, and 8 mg/kg tocilizumab monotherapy, with controls. Pooled summary odds ratios (ORs) were calculated using the Mantel-Haenszel method.

RESULTS

Six trials were analysed (four trials included 8 mg/kg tocilizumab and MTX combination therapy, three of which also assessed the 4 mg/kg dose). Three studies assessed tocilizumab monotherapy at 8 mg/kg. Pooled ORs revealed statistical significance for an increased risk of AEs in the 8 mg/kg combination group compared with controls (OR = 1.53; 95% CI 1.26, 1.86). The risk of infection was significantly higher in the 8 mg/kg combination group compared with controls (OR = 1.30; 95% CI 1.07, 1.58). No increased incidence of malignancy, tuberculosis reactivation or hepatitis was seen.

CONCLUSION

Tocilizumab in combination with MTX as a treatment for RA is associated with a small but significantly increased risk of AEs, which is comparable with that of other biologics. Vigilance for untoward effects is, therefore, imperative in any patient treated with these immuno-suppressive agents.