Psoriatic arthritis (PsA) is a complex heterogeneous disease involving the peripheral joints, affecting between 7% and 26% of psoriasis patients. Among the popular treatment options for psoriasis are tumor necrosis factor (TNF) inhibitors. A significant portion of psoriatic arthritis patients, however, fail to respond to TNF inhibitors.  Janssen announced last month that Tremfya (guselkumab) fared…