Magnetic Resonance Imaging (MRI) Results Following Discontinuation of Methotrexate in Rheumatoid Arthritis Treated with Subcutaneous Tocilizumab: The COMP-ACT MRI Substudy.

OBJECTIVE

To assess differences in joint damage and inflammation using magnetic resonance imaging (MRI) between patients with rheumatoid arthritis (RA) who achieved low disease activity with tocilizumab (TCZ) + methotrexate (MTX) and subsequently continued or discontinued MTX.

METHODS

In the COMP-ACT trial, US patients with RA received subcutaneous TCZ 162 mg + MTX. Those who achieved 28-joint count Disease Activity Score calculated with erythrocyte sedimentation rate (DAS28-ESR) ≤ 3.2 at Week 24 were randomized 1:1 (double-blind) to discontinue MTX (TCZ monotherapy; mono) or continue TCZ + MTX until Week 52. In a subset of patients, 1.5-Tesla MRI was used to obtain images of bilateral hands and wrists at weeks 24 and 40. Outcomes included changes in MRI-assessed synovitis, osteitis, erosion, and cartilage loss from Week 24 to Week 40, and in the proportion of patients with progression of each score.

RESULTS

Of 296 patients who achieved DAS28-ESR ≤ 3.2 at Week 24, 79 were enrolled in the pilot MRI substudy and randomized to TCZ mono (n = 38) or TCZ + MTX (n = 41). Treatment with either TCZ mono or TCZ + MTX suppressed erosion progression, synovitis, osteitis, and cartilage loss. The proportion of patients with no progression in each outcome measure was similar between groups (range, TCZ mono: 84.8-97.0%; TCZ + MTX: 92.3-100%).

CONCLUSION

In a subset of patients who achieved low disease activity with TCZ + MTX, MRI changes were minimal in intraarticular inflammation and damage measures in patients who discontinued MTX versus those who continued TCZ + MTX.