Baricitinib Monotherapy May Improve Rheumatoid Arthritis Disease Activity

Baricitinib monotherapy may improve disease activity in rheumatoid arthritis (RA), resulting in acceptable disease control, according to research published in Arthritis Care and Research. Researchers also suggest that among patients who do not respond to this therapy, the addition of methotrexate (MTX) may improve clinical response.

Researchers conducted a post hoc analysis of patients from the RA-BEGIN trial (NCT01711359) who entered the RA-BEYOND extension study (NCT01885078) to examine the long-term safety and efficacy of baricitinib 4-mg monotherapy in patients with active RA.

The RA-BEYOND cohort included 423 patients. All patients were treated with once-daily baricitinib 4-mg monotherapy. Patients who were treated with MTX in RA-BEGIN were switched to baricitinib 4-mg monotherapy; those who were treated with baricitinib 4-mg plus MTX had MTX discontinued, and those who were treated with baricitinib monotherapy continued that treatment.

Within the cohort, 47% of patients maintained baricitinib monotherapy through week 24. The remaining patients (53%) were prescribed background MTX; these patients were proportionally divided across the original 3 treatment arms of RA-BEGIN.

Researchers assessed American College of Rheumatology (ACR) responses at weeks 0, 12, and 24 of the RA-BEYOND trial. Among patients who switched from MTX monotherapy to baricitinib monotherapy, ACR20 responses were maintained, and improvements in ACR50 and ACR70 responses were noted. Among patients who had MTX prescribed, improvements from baseline among all 3 measures were noted.

Patients treated with combination baricitinib plus MTX in RA-BEGIN who maintained baricitinib monotherapy in RA-BEYOND did experience a decrease in ACR20, ACR50, and ACR70 responses: However, patients in this group who had MTX prescribed during RA-BEYOND maintained these responses.

Throughout all treatment groups, patients who had MTX prescribed during RA-BEYOND had a higher least squares mean Clinical Disease Activity Index, Simplified Disease Activity Index, and Health Assessment Questionnaire-Disability Index scores at week 0 compared with those who did not receive MTX.

In terms of safety, 50% of patients reported a treatment-emergent adverse event, the most common of which were nasopharyngitis, upper respiratory tract infections, and urinary tract infections. A low number of adverse events leading to permanent study drug discontinuation were reported, with a similar frequency across treatment arms.

Limitations to the study include the open-label, nonrandomized evaluation of patients as well as the post hoc nature of the study; this data should be interpreted with caution, and generalizability is not possible.

“These data suggest that a patient who tolerates MTX but has continued unacceptable levels of disease activity may benefit from the addition of baricitinib to MTX,” the researchers of the study concluded. “In patients who achieve their treatment target, one can consider tapering or discontinuing MTX, with the readdition of MTX if the patient flares.”  

This study was sponsored by Eli Lilly and Company and Incyte Corporation. Drs Fleischmann, Takeuchi, Schiff, Schlichting, Xie, Issa, Stoykov, Lisse, Martinez-Osuna, Rooney, and Zerbini report relationships with the pharmaceutical industry. For a complete list of disclosures, please see the full text of the study online.

Reference
Fleischmann R, Takeuchi T, Schiff M, et al. Efficacy and safety of long term baricitinib with and without methotrexate for the treatment of rheumatoid arthritis: experience with baricitinib monotherapy continuation or after switching from methotrexate monotherapy or baricitinib plus methotrexate [published online June 24, 2019]. Arthritis Care Res. doi: 10.1002/acr.24007