Anticytokine therapy in non-rheumatoid arthritis indications in 2009

Emerging drugs for psoriatic arthritis

IMPORTANCE OF THE FIELD

The socioeconomic burden of psoriatic arthritis (PsA) is considerable and not different from that of rheumatoid arthritis. Current treatment options do not always allow reaching the therapeutic objectives consisting of the remission of symptoms and prevention of the appearance of damage in the early stage of PsA or the blocking of PsA progression in the established cases.

AREAS COVERED IN THIS REVIEW

After reviewing the current treatment choices, we examine the new drugs in clinical Phase II and III trials for PsA up to January 2010. Information was mainly obtained from the network of international clinical trial registries.

WHAT THE READER WILL GAIN

The current management of PsA includes NSAIDs, corticosteroids, disease-modifying antirheumatic drugs (DMARDs) and anti-TNF-alpha blocking agents. These last drugs are more effective than traditional DMARDs on symptoms/signs of inflammation, quality of life and function and can inhibit the progression of the structural joint damage. Recent advancement in the knowledge of the immunopathogenesis of PsA has permitted the development of novel drugs including new TNF-alpha blockers, IL-1, -6, -12, -23 and -17 inhibitors, co-stimulator modulation inhibitors, B-cell depleting agents, small molecules and receptor activator of NF-kappaB/receptor activator of NF-kappaB ligand inhibitors.

TAKE HOME MESSAGE

The currently available anti-TNF-alpha blocking agents have revolutionized the management of PsA. However, there is a need for more effective and safer drugs.

Recent advances in neutralizing the IL-6 pathway in arthritis

Recent advances in understanding the mechanism(s) of how IL-6 trans-signaling regulates immune cell function and promotes inflammation in autoimmune arthritis are critically reviewed. Serum and/or synovial fluid (SF) IL-6 is markedly elevated in adult and juvenile rheumatoid arthritis (RA), psoriatic arthritis (PsA), ankylosing spondylitis (AS) and osteoarthritis (OA). IL-6, in concert with IL-17, determines the fate of CD4⁺ lymphocytes and therefore TH₁₇ cell differentiation. IL-6 also plays a critical role in modulating B-lymphocyte activity. The recognition that IL-6 trans-signaling regulates inflammation resulted in the development of tocilizumab, a fully humanized monoclonal antibody that neutralizes the biological activity of the IL-6-receptor (IL-6R). Significant clinical benefit was demonstrated as well as reduced serum IL-6 levels with suppression of X-ray progression of disease in several clinical trials in which juvenile or adult RA patients were treated with tocilizumab monotherapy or tocilizumab plus methotrexate. However, levels of serum and/or SF IL-6 cytokine protein superfamily members, adiponectin, oncostatin M, pre-B-cell colony enhancing factor/visfatin and leukemia inhibitory factor are also elevated in RA. Additional studies will be required to determine if anti-IL-6 trans-signaling inhibition strategies with tocilizumab or recombinant soluble IL-6R reduce the level of these cytokines.