The use of peficitinib (ASP015K), a pan-Janus kinase inhibitor, improves efficacy and is well tolerated over 32 months on an average in rheumatoid arthritis (RA) patients, illustrated a long-term study of peficitinib issued in Rheumatology and Therapy journal.

The safety, tolerability, and effectiveness of peficitinib (ASP015K) in patients with RA was evaluated by Tsutomu Takeuchi et al. Patients who formerly accomplished the RAJ1, or RAJ3 and RAJ4 trial, peficitinib studies were included. They were given peficitinib oral 50 or 100 mg daily with a dose increase of 150 mg or decrease of 50 mg daily to be allowed. The American College of Rheumatology (ACR) response rates and 28-joint Disease Activity Score with C-reactive protein (DAS28-CRP) were considered as efficacy endpoints. Therapy related adverse events (TEAEs), and incidence rates (IRs) of adverse events of particular interest for each 100 patient years (PY) were regarded as safety endpoints.

On the whole, 843 patients received peficitinib for a mean 32.0 months. Many (64.4%) patients received peficitinib 100 mg daily as the maximum dose. The respective ACR20/50/70 response rates were sustained from baseline to end of therapy. Continuous progresses in ACR components and DAS28-CRP were detected from the starting of the earlier studies and through the long-term extension study under consideration.

About 94.4% patients had TEAEs (common ones- Nasopharyngitis (47.0%) and herpes zoster (17.3%)) ; mostly with a severity score 1/2. Drug-linked TEAEs causing permanent withdrawal arose in 16.6% of patients. One dealth occured due to diffuse large B cell lymphoma and second death due to pneumonia, most likely connected to peficitinib.

The study results sustained the interim analysis of the long-term extension study, and encourage the use of this pan-Janus kinase inhibitor for long-term RA management.