Background Clinical efficacy of subcutaneous tocilizumab (SC-TCZ) has been demonstrated in rheumatoid arthritis (RA); however the effect of SC-TCZ on joint damage has not yet been assessed. AC-CUTE (NCT01951170) aimed to evaluate the effects of weekly SC-TCZ on structural change in patients (pts) with moderate-severe active RA, who were inadequate responders to MTX/MTX-intolerant or inadequate responders to a single anti-TNF.

Objectives To assess radiographic and MRI progression at week 24, in pts receiving SC-TCZ as monotherapy or in combination with MTX and/or conventional (c) DMARDs.

Methods An open-label, multi-centre, prospective, single-arm study. Pts received TCZ 162mg weekly, single fixed dose SC injection, monotherapy or in combination with MTX or other cDMARDs. Primary endpoint was absolute change in radiographic Genant-modified Sharp Score (mTSS) between screening and week-24. Secondary endpoints were absolute change from baseline in RAMRIS of MRI erosions, synovitis and osteitis, and MRI cartilage loss (CARLOS). Efficacy parameters included change from baseline (initiation of SC-TCZ) in mTSS, DAS28, CDAI, SDAI and ACR20/50/70. The full analysis set population included pts who received at least 1 dose SC-TCZ, and was used for reporting safety, tolerability and efficacy. Subgroup analyses were split into SC-TCZ monotherapy [SC-TCZM: SC-TCZ monotherapy or SC-TCZ+cDMARDs other than MTX] and SC-TCZ in combination [SC-TCZC: SC-TCZ+cDMARDs including all MTX regimens].

Results 52 pts enrolled from 10 Australian sites; majority females (79%), median age 59 yrs (min 28, max 79) and 5 yrs (min 0, max 31) median duration of RA. Pts in SC-TCZM had longer disease duration at baseline and higher mTSS score. 29 pts completed 24 weeks of treatment. Mean change from baseline for erosion/JSN/mTSS was 0.162/0.485/0.647 in SC-TCZM and 0.124/0.238/0.362 in SC-TCZC respectively; changes relative to baseline and between subgroups were not significant (p>0.05). Mean changes from baseline in MRI erosion/cartilage loss/synovitis/osteitis were 0.794/0.0882/-1.56/-2.88 for SC-TCZM and 0.955/0.1439/-1.68/-3.77 for SC-TCZC. Change from baseline for each MRI measure within SC-TCZC was significant (p<0.05); however no significant differences were observed between the 2 subgroups (p>0.1). At 24 weeks, decrease in DAS28 from baseline was significant for both subgroups (p=0.004 for SC-TCZC; p<0.0001 for SC-TCZM); however no significance was observed between subgroups (p=0.3). The proportion of pts achieving DAS28 remission (<2.6) over 24 weeks ranged from 65% for SC-TCZC to 89% for SC-TCZM. 3 pts reported serious adverse events, asthma, anaemia and Weber B Ankle Fracture; deemed unrelated to study medication.

Conclusions There was no significant radiographic progression during the study period across groups. Mean changes in MRI variables were not significant in SC-TZM. MRI changes in SC-TCZC were significant for joint damage progression, as well as regression of synovitis and osteitis.

Acknowledgement Sponsored by Roche Products, Pty. Ltd. Medical writing provided by Joseline Ojaimi from Roche.

Disclosure of Interest P. Bird: None declared, C. Peterfy Consultant for: Roche Products, Pty. Ltd, J. DiCarlo Consultant for: Roche Products, Pty. Ltd, F. Joshua: None declared, S. Hall: None declared, H. Griffiths: None declared, P. Youssef: None declared, R. Barrett Employee of: Roche Products, Pty. Ltd, P. Button Employee of: Roche Products, Pty. Ltd