Some patients with rheumatoid arthritis (RA) who achieved low disease activity with tocilizumab plus methotrexate (MTX) combination therapy maintained disease control with minimal evidence of intra-articular inflammation upon discontinuing MTX, according to research published in Journal of Rheumatology.

Researchers used data from the COMP-ACT study (ClinicalTrials.gov identifier: NCT01855789), a randomized, multicenter, double-blind, parallel-group, 52-week study with an 8-week follow-up period, to conduct a substudy examining differences in active intra-articular inflammation and joint changes via magnetic resonance imaging (MRI).

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All participants had moderate-to-severe RA based on the revised 1987 American College of Rheumatology criteria. Participants from the COMP-ACT study who achieved low disease activity (Disease Activity Score 28 with erythrocyte sedimentation rate  ≤3.2 at week 24) were eligible to participate in the substudy.

Of the 296 patients who met the required Disease Activity Score 28 with erythrocyte sedimentation rate criteria, 79 were enrolled in the substudy and randomly assigned 1:1 to receive either tocilizumab monotherapy (n=38) or tocilizumab plus MTX combination therapy (n=41). MRI for both hands and wrists were available for analysis.

At week 24, MRI scores were similar between the 2 treatment groups. By week 40, both treatment groups demonstrated “minimal numerical changes” in bone erosion, synovitis, osteitis, and cartilage loss (between-group differences of 0.24, 0.06, 0.53, and -0.23, respectively); no clinically meaningful difference was noted between the groups.

Additionally, MRI results were consistent for bilateral hand and wrist images and for the dominant hand and wrist (mean difference 0.43, 0.11, 1.07, and -0.16 for bone erosion, synovitis, osteitis, and cartilage loss, respectively).

At week 40, a majority of patients in both groups did not have MRI evidence of progression in both bilateral and dominant hand and wrist images, with similar between-group differences (range tocilizumab monotherapy 87.9%-100%; range tocilizumab plus methotrexate 89.7%-97.4%).

Limitations included the small sample size and “small differences in the changes among MRI features examined,” the lack of gadolinium-based contrast use, which may have decreased both sensitivity and specificity, the lack of baseline MRI results before treatment with tocilizumab, and the short substudy period.

“In a subset of patients who achieved [low disease activity] with [tocilizumab plus MTX] and were included in this MRI pilot substudy, minimal further MRI-assessed changes were observed in those who discontinued [methotrexate] and those who continued MTX”, the researchers of the study concluded.

Disclosure: This study was funded by Genentech, Inc. Multiple authors report relationships with the pharmaceutical companies. For a complete list of disclosures, please see the full text of the study online.

Reference

Peterfy C, Kremer J, Rigby W, et al. MRI results following discontinuation of methotrexate in patients with rheumatoid arthritis treated with subcutaneous tocilizumab: the COMP-ACT MRI substudy [published online June 1, 2019]. J Rheumatol. doi:10.3899/jrheum.180953