Ixekizumab Effective in TNF Failure Psoriatic Arthritis - SPIRIT-P2 Trial Save

Ixekizumab (Taltz) is currently approved for use in plaque psoriasis and is being developed for use in psoriatic arthritis (PsA). New results show IXE to be highly effective at skin and joint outcomes in PsA patients who have failed a TNF inhibitor (TNFi).

Previously, the SPIRT I trial demonstrated efficacy and safety of ixekizumab (IXE) in patients who were biologic DMARD-naive. In that 52-week study, 417 active PsA patients received either IXE 80 mg, IXE 40mg, adalumumab or placebo.  IXE patients showed significant improvement of arthritis, dactylitis and enthesitis along with impressive PASI 75 and PASI 90 results as well.

The current SPIRIT P2 trial assessed the efficacy of IXE in patient not responding to TNFi.  In this phase 3 trial, 363 adults with psoriatic arthritis were assigned (1:1:1) subcutaneous IXE 80 mg every 4 weeks or IXE every 2 weeks after a 160 mg starting dose or placebo. The primary endpoint was ACR-20 response at week 24.

At week 24, ACR-20 responses were higher with with IXE every 4 weeks (53%) and IXE every 2 weeks (48%) compared to placebo (20%).

Serious adverse events were low (3% IXE q4wk; 7% IXE q2wk; 3% placebo) and there were no deaths. Three (2%) serious infections, were seen in the IXE 2 weeks group.

Both the 2-week and 4-week ixekizumab dosing regimens improved the signs and symptoms of patients with active psoriatic arthritis and who had previously inadequate response to tumour necrosis factor inhibitors, with a safety profile consistent with previous studies investigating ixekizumab.