Peficitinib

Abstract

Peficitinib is a Janus kinase（JAK）inhibitor, that was developed and approved for rheumatoid arthritis（RA）in Japan. Among five kinds of JAK inhibitors approved for RA in Japan, pefecitinib has a unique feature that demonstrates the inhibition of all kinds of JAK molecules. i.e JAK1, JAK2, JAK3 and Tyk2. Plasma concentration of peficitinib is similar between individuals with normal and impaired renal function, so dose adjustment based on renal function is not needed. To date, there are three phase 2b trials（RA21, RA22, RAJ1）and two phase 3 trials（RAJ3, RAJ4）conducted in global and Asia. In the phase 2b trials conducted in global, pefecitinib could not demonstrate the superiority due to high ACR20 response rate in the placebo group. In the phase 3 trials conducted in Asia, both the peficitinib 100 mg/day and 150 mg/day showed significant improvement in ACR20, 50, 70 response compared to the placebo group. In addition, RAJ4 trial showed the superiority on suppressing joint destruction. Regarding safety, the incidence of herpes zoster was comparable with other JAK inhibitors. The long-term safety for malignancy and major adverse cardiovascular events needs to be further investigated in the future.