About 20% of patients with psoriasis develop psoriatic arthritis as a result. This arthritis can be quite difficult to manage. In addition to the drugs already available, there are three new drugs for this, and the most effective of these is secukinumab, an antibody against IL-17.
It seems to be fairly safe and pretty effective against both the skin and the joint disease. The National Institute for Clinical Excellent (NICE) are considering approving it for the joints - their next guidance is due in February 2017