TOKYO, March 26, 2019  - Astellas Pharma Inc. (TSE: 4503, President and CEO: Kenji Yasukawa, Ph.D., “Astellas” ) today announced that Smyraf® 50 mg and 100 mg  Tablets (generic name: peficitinib hydrobromide), an oral Janus kinase (JAK) inhibitor, received manufacturing and marketing approval in Japan for the treatment of rheumatoid arthritis (including prevention of structural joint damage) in patients who have an inadequate response to conventional therapies.

Smyraf®, which was discovered by Astellas, suppresses activation and proliferation of inflammatory cells involved in synovial inflammation and joint destruction in rheumatoid arthritis patients by inhibiting various inflammatory cytokine signaling pathways.

The approval is based mainly on the results from two Phase 3 trials (RAJ3*1 and RAJ4*2) of peficitinib in rheumatoid arthritis patients who had an inadequate response to conventional therapy. Both trials demonstrated superiority over placebo and met the primary endpoints. The safety analysis of these trial appears consistent with the safety profile of peficitinib in previous clinical trials and no new safety signals were observed.

The number of rheumatoid arthritis patients in Japan is estimated to be approximately 0.6 to 1 million*3. By providing Smyraf®  as a new therapeutic option, Astellas will contribute to treatment of rheumatoid arthritis patients with an inadequate response to conventional therapy such as Methotrexate (MTX) and disease-modifying antirheumatic drugs (DMARDs)*4.