Role of novel biological therapies in psoriatic arthritis - Effects on joints and skin

Psoriatic arthritis (PsA) is a partly debilitating disease that may affect small and large joints and the spine. Patients with PsA are divided into different subgroups according to joint involvement and their disease may be classified as part of the spectrum of spondyloarthritides or seronegative rheumatoid arthritis. Traditional treatment comprises nonsteroidal anti-inflammatory drugs, systemic and intra-articular corticosteroids and disease-modifying antirheumatic drugs such as sulfasalazine, methotrexate and cyclosporin. On the basis of the very recent studies performed in the US and Germany, patients with severe disease can be treated with anti-tumour necrosis factor (TNF) therapy. Biologicals such as etanercept and infliximab have been used successfully to treat PsA. While etanercept is a 75kD TNF receptor fusion protein that binds to TNFalpha and TNFbeta, infliximab is a chimeric monoclonal antibody that binds to TNFalpha both in its soluble form in the serum and on the cell membrane. Adalimumab is a fully humanised antibody recognising TNFalpha that has not been tested in PsA to date. Another biological agent, alefacept, is directed against the adhesion molecule lymphocyte function-associated antigen (LFA)-2, which is known to interfere with T-cell activation. Alefacept has been shown to be efficacious in a limited number of patients with PsA. Taken together, there has been definite recent progress in the treatment of PsA. Severely affected patients may especially have substantial benefit from therapy with biologicals directed against TNFalpha and other targets.