The role of upadacitinib in the treatment of moderate-to-severe active rheumatoid arthritis.

Despite recent promising developments in the treatment of rheumatoid arthritis (RA), a substantial proportion of patients still cannot achieve the treatment targets: low disease activity and remission. Janus kinase (JAK) inhibitors have the potential to fill this important gap with their high efficiency, rapid onset of action, and acceptable safety profile. The fact that the previously approved two JAK inhibitors, tofacitinib and baricitinib, inhibit more than one JAK molecule raised the question whether a safer profile can be possible by inhibiting fewer JAK molecules. Upadacitinib, a JAK 1 selective molecule developed in this context has been evaluated in the SELECT phase-III study program and demonstrated a high and rapid efficacy in monotherapy as well as in combination with csDMARDs both in csDMARD-naive RA patients and in patients refractory to csDMARD and bDMARD treatments. Upadacitinib 15 mg once daily displayed a similar safety profile except for increased creatine phosphokinase (CPK) levels and herpes zoster (HZ) risk compared to its active comparators methotrexate (MTX) and adalimumab. Most of the CPK elevations were asymptomatic, and most of the HZ cases were not serious. Along with the randomized-controlled studies and meta-analysis results, upadacitinib 15 mg once daily has a favorable efficacy/safety profile. Long-term extensions of current studies and real-world data will be important to fully appreciate its potential in the treatment of RA.