The safety profile is consistent with previous studies of the ixekizumab.
Jordi Gratacos-Masmitja, MD, PhD
Ixekizumab may be beneficial in improving the signs and symptoms of psoriatic arthritis.
The findings come from research published as part of the European E-Congress of Rheumatology 2020 (EULAR 2020) meeting due to the cancellation of the in-person meeting. Investigators found in the SPIRIT-P2 trial, ixekizumab every 2 or 4 weeks was superior to placebo for patients with the condition.
Jordi Gratacos-Masmitja, MD, PhD, from University Hospital Parc Tauli Sabadell in Barcelona, Spain, and a team of investigators determined the efficacy and safety of ixekizumab treatment up to 3 years in patients with psoriatic arthritis. Patients included had prior inadequate response or intolerance to 1-2 tumor necrosis factor inhibitors.
Gratacos-Masmitja and the team included 310 patients in the extension period in which patients maintained their original dose of ixekizumab. Placebo patients received the drug every 2 or 4 weeks. Patients were discontinued if they failed to demonstrate >20% improvement in both tender and swollen joint counts at week 32 or any visit following. To measure efficacy, the investigators recorded ACR20/50/70 response, Psoriasis Area and Severity Index 75/90/100 response, Leeds Enthesitis Index, Leeds Dactylitis Index-Basic, Minimal Disease Activity, and Disease Activity in Psoriatic Arthritis.
Overall, 245 patients were initially randomized to ixekizumab at week 9 with intent-to-treat. Of those patients, 26.1% discontinued due to lack of efficacy and 9% of patients were excluded due to mandatory discontinuation criteria.
The patients included in the study who received ixekizumab every 4 and every 2 weeks for 156 weeks showed a sustained improvement in ACR responses and manifestations of psoriatic arthritis. Manifestations improved included enthesitis, dactylitis, and skin outcomes. Treat-to-target measures including Minimal Disease Activity and Disease Activity in Psoriatic Arthritis (low disease activity or remission) were reached by 30.8% and 47.7% of patients on ixekizumab every 4 weeks, and by 29.2% and 40.7% of patients on ixekizumab every 2 weeks.
The investigators analyzed the safety of the ixekizumab in patients who were exposed to at least 1 dose of it. There was 1 patient who reported serious adverse events of anal fistula and anal abscess during the double-blind treatment period (weeks 0-24). The serious adverse events were initially considered to be inflammatory bowel disease, but an external team reviewed the case and determined such events were not inflammatory bowel disease.
In total, the incidence rate per 100 patient-years of treatment-emergent adverse events was 48.5 for patients in the 2 weeks group and 40.9 in the ixekizumab every 4 weeks group. Most of the treatment-emergent adverse events were mild or moderate in severity. However, 5.9% of patients discontinued the treatment due to adverse events. The most common were infections (IR=33.1) and injection site reactions (IR=5.4). There were 3 deaths reported during the study.
Still, the investigators found patients who were treated with ixekizumab who had prior inadequate response or intolerance to 1 or 2 tumor necrosis factor inhibitors had improvements in the signs and symptoms of psoriatic arthritis persisting for up to 3 years. The team noted the safety profile was consistent with previous studies of the drug.
The study, “Efficacy and Safety of Ixekizumab in Patients With Psoriatic Arthritis and Inadequate Response to TNF Inhibitors: Three Year Results From a Phase 3 Study,” was published online on the EULAR 2020 website.